HK1114130A - High pressure gas jet impingement heat treatment system - Google Patents

Description

High-pressure gas jet impact heat treatment system

Technical Field

The present invention relates generally to the field of casting processes, and more particularly to heat treatment of metal castings.

Background

In the field of metal processing, it is known that heat treatment of metal workpieces often requires a significant amount of time to achieve suitable formation characteristics. Accordingly, methods for reducing the time required to heat treat a workpiece are always desirable.

Drawings

Various objects, features and advantages of the present invention will become apparent upon reading the specification in conjunction with the drawings. The dimensions shown in the figures are only intended to represent an example of an embodiment of the present invention. The sections denoted by "Z" (e.g., Z1, Z2, etc.) represent the various zones of a multi-zone furnace.

FIG. 1 is a perspective view of an exemplary casting that may be heat treated in accordance with the present invention;

FIG. 2 is a top view of an exemplary system of the present invention;

FIG. 3 is a cross-sectional view of the exemplary heat treatment furnace shown in FIG. 2 along line A-A;

FIG. 4 is a cross-sectional view of the exemplary aging oven shown in FIG. 2 taken along line B-B;

FIG. 5 is a cross-sectional view of the exemplary aging oven of FIG. 2 taken along line C-C;

FIG. 6 is a top view of another exemplary system of the present invention;

FIG. 7 is a cross-sectional view of the exemplary furnace shown in FIG. 6;

FIG. 8 is a cross-sectional view of the exemplary aging oven and cooler shown in FIG. 6;

FIG. 9 is a cross-sectional view of the "heating" region of the furnace of FIG. 6 taken along line D-D;

FIG. 10 is a cross-sectional view of the "keep warm" area of the furnace of FIG. 6 taken along line E-E;

FIG. 11 is a top view of an exemplary spin casting post-treatment system that may be used in accordance with the present invention;

FIG. 12 is a cross-sectional view of an exemplary heating zone of the heat treatment or aging furnace of FIG. 11;

FIG. 13 is a cross-sectional view of an exemplary heat-insulated region of the heat treatment furnace or aging furnace of FIG. 11;

FIG. 14a is a top view of another exemplary spin casting post-treatment system that may be used in accordance with the present invention;

FIG. 14b is a cross-sectional view of the furnace of FIG. 14a taken along line F-F;

FIG. 14c is an enlarged view of an exemplary heating zone of FIGS. 14a and 14 b;

FIG. 15 is a schematic illustration of an exemplary sand reclamation process used in aspects of the present invention;

FIG. 16 is a schematic view of an integrated example coring and sand reclamation system, wherein the coring unit includes a furnace;

FIG. 17 is a cross-sectional view of the furnace shown in FIG. 16;

FIG. 18 is another cross-sectional view of a portion of the furnace shown in FIG. 16; and

fig. 19 is a cross-sectional view of the furnace of fig. 18 taken along line 19-19.

Detailed Description

Briefly, the present invention is directed to a system for processing one or more metal workpieces. The workpiece may be a metal casting, a forged metal blank, or any other metal workpiece that requires or benefits from heat treatment. The system may be used to heat treat a workpiece formed using a sand mold or metal mold (optionally formed with one or more sand cores), or may be formed without using a sand mold, core or metal mold, and the sand mold, core and/or mold would be removed from the workpiece prior to heat treatment. The inventive system includes a heat treatment furnace having at least one "heating" zone. The system may include a mechanism for rotating and flipping the workpiece during heat treatment and/or removal of the mold and core.

U.S. patent application No.60/623716 (filed as 10/29/2004) and U.S. patent application No.60/667230 (filed as 4/1/2005) are both incorporated herein by reference in their entirety.

Formation of a workpiece

Methods for forming metal workpieces, such as vehicle wheels or cylinder heads or engine blocks for automobiles, are well known to those skilled in the art and are therefore only generally described herein.

For example, a typical forging process involves applying mechanical force to a preformed metal blank in order to cause the metal to assume a suitable shape. Cavity die (or "closed die") forging typically involves pressing metal between two dies with appropriate part profiles. Cold forging typically involves the application of mechanical force to deform the metal at about ambient temperature or above. Open die forging typically involves the use of a flat, non-profiled die. Seamless roll ring forging typically involves punching holes in a thicker round piece of metal, followed by rolling and extrusion to produce a thin ring.

As yet another example, a typical die casting process (also referred to as "solution metal forging") includes pouring molten metal into the lower half of a two-part preheated die. When the metal begins to solidify, the upper half of the mold closes and pressure is applied to the metal being pulled up. Thus, more complex parts can be manufactured with little pressure.

As yet another example, typical metal casting methods generally include pouring a molten metal or metal alloy into a mold or die to form a casting. The molten metal may be injected into the mold at high or low pressure, such as by gravity feed. The external features of a suitable casting to be formed are disposed on the inner surface of the mold or die. The castings were subjected to various combinations of the following process steps: removing the mold, coring (when used), heat treating, reclaiming the sand from the sand core (when used), and (sometimes) aging.

Various types of molds or dies may be used in the metal casting process, including but not limited to: wet sand molds, precision sand molds, semi-permanent molds, permanent metal molds, and investment molds.

In one aspect, the die or mold is a permanent die or mold, which may be formed of a metal such as cast iron, steel, or other material. In this aspect, the mold or die may have a clam shell design to facilitate removal of the casting therefrom. In another aspect, the mold is a precision sand mold that is generally formed from a mixture of particulate material (e.g., silica, zircon, other sand, or any combination thereof) and a binder (e.g., a phenolic resin or other suitable organic or inorganic binder material). In another aspect, the mold is a semi-permanent sand mold, formed from sand and a binder, or formed from a metal (e.g., steel) or a combination thereof.

In this and another aspect of the invention, one or more cores (not shown) may be used with the mold or die to create hollow cavities and/or casting details in the casting. The core is typically formed of a sand material and a suitable binder (e.g., phenolic resin, phenolic urethane "cold box" binder, or other suitable organic or inorganic binder material) as desired.

In yet another aspect, the mold is an investment mold. The investment casting process involves the use of a primary pattern, which is typically made by injecting wax or plastic into a metal mold. The mold is then coated by pouring or dipping with a refractory slurry (i.e., an aqueous slurry of silica and binder) that cures at ambient temperature to produce a mold or shell. After hardening, the mold is turned over and the primary pattern (wax or plastic) is melted out of the mold. To complete the refractory mold, one or more ceramic cores may be inserted. Investment castings can be made of virtually any castable metal or alloy.

As shown in fig. 1, each die or mold 115 generally includes a plurality of side walls 135, a top wall or wall 140, and a bottom wall or bottom 145 that define an interior cavity 150 into which molten metal is poured 150. The internal cavity 150 is formed with a male and female pattern for forming internal features of the casting 125. A pouring opening 155 is disposed in each mold's side wall 135, upper wall 140 or bottom wall 145 and communicates with the interior cavity 150 to enable molten metal to be poured or otherwise introduced into the mold. The resulting casting 125 features an internal cavity 150 of the mold 115, where one or more sand cores are used, and additional core holes or access openings 160 formed therein where one or more sand cores are used.

In addition, the mold may be provided with one or more riser holes (not shown) to serve as a reservoir for the molten metal. These reservoirs provide additional metal to fill voids formed due to shrinkage as the metal cools and changes from a liquid to a solid. The solidified metal in the risers remains attached to the casting as bumps or "risers" (not shown) when the cast product is removed from the mold. These risers are not used and will be removed later, usually by mechanical means.

A heat source or element (e.g., a hot air blower or other suitable gas fired heater mechanism, an electric heater mechanism, a fluidized bed, or any combination thereof) may be disposed near the pouring station for preheating the molds. Typically, the mold is preheated to a suitable temperature depending on the metal or alloy used to form the casting. For example, for aluminum, the mold may be preheated to a temperature of from about 400 ℃ to about 600 ℃. The different preheating temperatures required to preheat the various metal alloys and other metals used to form the castings are well known to those skilled in the art and can include a wide temperature range from about 400 c to above and below about 600 c. In addition, some mold types require lower processing temperatures in order to prevent damage to the mold during casting and curing. In this case and when the metal treatment temperature should be higher, a suitable metal temperature control method, such as induction heating, may be employed.

Alternatively, the mould may be provided with an internal heat source or elements for heating the mould. For example, the castings are formed in permanent type metal molds that include one or more cavities or passages formed adjacent the castings, and a heating medium, such as hot oil, is received by and/or flowed through the molds for heating the molds. Hot oil or other suitable medium may then be introduced or flowed through the mold with the oil at a reduced temperature (e.g., from about 250℃. to about 300℃.) to cool and solidify the castings. Hot oil at a higher temperature (e.g., heated to 500 c to about 550 c) can be introduced and/or flowed through the mold to inhibit cooling and to bring the temperature of the castings back up to the holding temperature for heat treatment. Preheating the mold and/or introducing a heating medium into the mold may be used to initially heat treat the casting. Moreover, preheating helps to maintain the metal of the castings at or near the heat treatment temperature to reduce heat loss as the molten metal is poured into the molds, solidified, and transferred to subsequent treatment stations for heat treatment. If desired, the castings may be conveyed through the radiant tunnel to prevent or minimize cooling of the castings.

Treatment of workpieces

It should be appreciated that the various aspects of the invention described herein may be used to process a variety of workpieces formed using any method.

FIGS. 2-10 illustrate exemplary processing systems in accordance with aspects of the present invention. The system may be used to treat a workpiece (fig. 2-5) formed in a sand mold (optionally with one or more sand cores). Alternatively, the system may be used to process workpieces formed without the use of sand molds or cores (FIGS. 6-10). Alternatively, the system may be used to treat a workpiece from which the sand molds and cores have been removed prior to heat treatment (fig. 6-10).

FIG. 2 shows an exemplary processing system 200 that includes a heat treatment furnace 210 (also referred to as a "solution furnace"), a quench 211, an aging furnace 212, and a cooling unit 213. The movement in and out of the furnace 210, the ageing furnace 212 and the cooling unit 213 and between them is performed by means of a robotic device or transport system 214 for continuous operation of the system 200. Workpiece 215 is shown as an automobile wheel, but it should be understood that other workpieces are also contemplated. If desired, a multi-tier "shelving" or "stacking" system (e.g., as shown in FIGS. 3-5) may also be used to increase the capacity of the furnace 210, furnace 212, and/or cooling unit 213. The mechanism for conveying the components through the furnace and the oven may include a basket system, such as those known to those skilled in the art. Alternatively, a direct contact transfer mechanism (e.g., chain 216, rollers, walking beams, or other suitable mechanism may be used.

Generally, during transfer of the workpiece from the forming station to the heat treatment station or furnace, the workpiece may be exposed to the environment outside of the casting plant or metal processing equipment, particularly when the workpiece can be left for any suitable time. Thus, the workpiece will be rapidly cooled from a molten or semi-molten temperature. While some cooling is required to solidify the workpiece, it has been found that when the metal of the workpiece is cooled, it is brought to a temperature or temperature range hereinafter referred to as the "process control temperature" or "process critical temperature", and below which the time required to raise the temperature of the workpiece to the heat treatment temperature and perform the heat treatment is significantly increased. In one aspect, it has been found that for certain types of metals, a reduction in the temperature of the workpiece below its process control temperature requires an additional heat treatment time of several minutes for each one minute to obtain suitable formation characteristics. For example, ten minutes to lower the metal temperature of the workpiece to the low pressure process control temperature would likely require tens of minutes of additional heat treatment time. For example, it has been found that for certain types of metals, lowering the temperature of the workpiece below its process control temperature requires at least about 2 minutes of additional heat treatment time for every one minute to achieve suitable results. As another example, it has been found that for certain types of metals, lowering the temperature of the workpiece below its process control temperature requires at least about 3 minutes of additional heat treatment time for every one minute to achieve suitable results. As a further example, it was found that for certain types of metals, an additional heat treatment time of at least about 4 minutes is required to achieve suitable results for every one minute of duration for the workpiece temperature to drop below its process control temperature. In this example, ten minutes of lowering the workpiece metal temperature below the process control temperature would likely require an additional heat treatment time in excess of 40 minutes to achieve the appropriate physical properties. Typically, many workpieces must be heat treated for 2 to 6 hours to achieve a suitable heat treatment effect, in some cases for longer periods of time. This results in the use of more energy and therefore more costly heat treatments.

One skilled in the art will appreciate that the process control temperature of a workpiece processed by the present invention will vary depending on the particular metal and/or metal alloy used for the workpiece, the size and shape of the workpiece, and a variety of other factors.

In one aspect, the process control temperature may be about 400 ℃ for some alloys or metals. In another aspect, the process control temperature can be about 400 ℃ to about 600 ℃. In another aspect, the process control temperature can be about 600 ℃ to about 800 ℃. In yet another aspect, the process control temperature can be from about 800 ℃ to about 1100 ℃. In yet another aspect, the process control temperature may be from about 1000 ℃ to about 1300 ℃ for certain alloys or metals (e.g., iron). In one particular embodiment, the aluminum/copper alloy may have a process control temperature of from about 400 ℃ to about 470 ℃. In this example, the process control temperature is below the solution heat treatment temperature of most copper alloys (which is typically from 475 ℃ to about 495 ℃). Although specific examples are provided herein, it should be appreciated that the process control temperature may be any temperature depending on the particular metal and/or metal alloy used for the workpiece, the size and shape of the workpiece, and a variety of other factors.

When the metal of the workpiece is within the appropriate process control temperature range, the workpiece will typically be cooled sufficiently to solidify as desired. However, while the metal of the workpiece is capable of cooling below its process control temperature, it has been found that cooling the metal of the workpiece below the process control temperature for a few additional minutes per minute may require the workpiece to be heated to a suitable heat treatment temperature, such as from about 475 ℃ to about 495 ℃ for an aluminum/copper alloy and from about 510 ℃ to about 570 ℃ for an aluminum/magnesium alloy. Thus, the time required to properly and completely heat treat the workpieces may also increase substantially when the workpieces are cooled below their process control temperature for even a short period of time. In addition, it should be appreciated that in a batch processing system, where multiple workpieces are processed in a batch by a thermal processing station, the thermal processing time for an entire batch of workpieces is generally dependent upon the thermal processing time required for the lowest temperature workpiece in the batch. Thus, when one workpiece of a batch to be processed is cooled to a temperature below its process control temperature, for example, for about 10 minutes, the entire batch of workpieces typically requires heat treatment, for example, for at least an additional 40 minutes, in order to ensure that all of the workpieces are properly and completely heat treated.

Thus, a different aspect of the invention relates to a system designed to move and/or convey workpieces (in their molds or separate from the molds) from a pouring station to a heat treatment station or furnace while cooling the molten metal to or above the process control temperature of the metal, but below or equal to its suitable heat treatment temperature, so as to allow the workpieces to solidify. Accordingly, various aspects of the present invention include a system for monitoring the temperature of a workpiece to ensure that the workpiece is maintained substantially at or above a process control temperature. For example, thermocouples or other similar temperature sensing devices or systems may be disposed on or near the workpiece or at spaced locations along the path of travel of the workpiece from the casting station to the heat treatment furnace for substantially continuous monitoring. Alternatively, periodic interval monitoring (determined to be sufficient frequency) may be employed. The device may be in communication with a heat source such that the temperature measuring or sensing device and the heat source may cooperate to maintain the temperature of the workpiece substantially at or above a process control temperature of the metal of the workpiece. It should be appreciated that the temperature of the workpiece may be measured at a particular location on the workpiece, may be an average temperature calculated by measuring the temperature at multiple locations on the workpiece, or may be measured in any other manner as desired for a particular application. Thus, for example, the workpiece temperature may be measured in a plurality of locations on the workpiece, and an overall temperature value may be calculated, or the lowest detected temperature, the highest detected temperature, an intermediate detected temperature, an average detected temperature, or any combination or variation thereof, determined.

Additionally, prior to entering the furnace, the workpieces may pass through the entire entry or exit region where the temperature of each workpiece is monitored to determine if the workpiece has cooled to a point where excess energy is required to raise the temperature to the heat treatment temperature. The inlet zone may be contained in the process control temperature station or may be a separate zone, as shown in the various figures. The temperature of the workpiece may be monitored by suitable temperature sensing or measuring devices, such as thermocouples, to determine whether the temperature of the workpiece has reached or dropped below a predetermined or predetermined exclusion temperature. In one aspect, the predetermined exclusion temperature may be a temperature (e.g., from about 10 ℃ to about 20 ℃) that is below the process control temperature of the workpiece metal. In another aspect, the predetermined exclusion temperature may be a temperature that is less than the heat treatment temperature of the heat treatment furnace or furnaces (e.g., from about 10 ℃ to about 20 ℃). When the workpiece is cooled to a temperature equal to or lower than a predetermined temperature, the control system sends a removal signal to the transfer or removal mechanism. Upon detection of the fault condition or signal, the target workpiece may be evaluated for further evaluation or may be removed from the conveyor line. The workpiece may be removed by any suitable mechanism or device, including but not limited to a robotic arm or other automated device, or the workpiece may be manually removed by an operator.

Thus, it should be appreciated that the temperature of the workpiece may be measured at a particular location on the workpiece, may be an average temperature calculated by measuring the temperature at a plurality of locations on the workpiece, or may be measured in any other manner as desired for a particular application. Thus, for example, the temperature of the workpiece may be measured in multiple locations on the workpiece, and the overall value may calculate or determine a lowest detected temperature, a highest detected temperature, an intermediate detected temperature, an average detected temperature, or any combination or variation thereof.

When a mold is used, the mold may be preheated to help maintain the metal temperature at or above the predetermined process control temperature. Additionally or alternatively, the casting or forming station may be located near the heat treatment furnace to limit temperature loss of the mold and/or workpiece as the mold moves from the casting station to the furnace. Also, a temperature-maintaining chamber, radiant tunnel, or other device or system may be used at or near the entrance to the furnace to maintain the temperature of the metal at or above the process control temperature. The advantages of maintaining the temperature of the workpiece at or above the process control temperature are further described in U.S. patent application No.10/051666, which is incorporated herein in its entirety by reference. However, in some processes, the workpiece may enter the thermal treatment furnace below a predetermined process control temperature.

If desired, the entire outer sand mould or a part of the sand mould may be removed before entering the furnace. Various techniques for removing sand molds are provided in U.S. patent No.6622775, which is incorporated herein in its entirety. Additional techniques for removing the mold are provided in U.S. patent application No.10/616750, which is incorporated herein in its entirety. Other mechanical techniques known in the industry (chiseling, vibrating, etc.) are also contemplated. The removed sand molds may be transferred to a sand reclamation facility where the sand is cleaned for reuse or deposited in a furnace for reclamation as described further below.

Referring to fig. 2, the furnace 210 and the aging furnace 212 may each include one or more high pressure heating zones ("heating" zones) 218a, 218b, 218c, 218d, 218e that provide a locally directed high pressure fluid flow to each workpiece 215 rather than (or in addition to) a common bulk air flow. Autoclaving can provide a number of advantages depending on the type of workpiece used.

For example, when a mold or core is not used (or it has been removed), the system of the present invention may exhibit a reduction in heat treatment time of almost 20%. In addition, high pressure impingement of the fluid at the workpiece may be shown to reduce the demold and/or decoring time and the overall heat treatment time. When the mold/core is formed using a combustible formulation, the fluid medium also enhances removal of the mold/core by adding oxygen to promote binder combustion. When the mold/core is formed of inorganic or organic, water-soluble components, the pressurized fluid medium assists in removal by direct contact (jet) reaction of the pressurized fluid with the mold/core. Moreover, the actual "harsh" force of the medium can assist in removing the die and/or core components by causing the die and/or core components to move away from the workpiece. For example, by placing one or more nozzles within 2 inches of the workpiece, the sand retained around the workpiece may be reduced by almost 50%. It will be appreciated that the heat treatment time can be further reduced by the specific binder composition.

FIGS. 3 and 4 illustrate exemplary heating zones 218a, 218e in the heat treatment furnace 210 and the aging furnace 212, respectively, of FIG. 2. The heating zones 218a, 218e include fluid channel conduit systems 219, 219' for directing the flow of fluid at the workpiece 215. The system includes a supply of air or other fluid that may be heated by one or more burners 220, 220'. The channel conduit system 219, 219 'directs air toward the workpiece through one or more holes, slots, nozzles, impingement tubes, or any other fluid flow device or system known in the art (collectively "impingement devices") (denoted as elements 221, 221'). The channel conduit system may include a plurality of zones or stations sequentially positioned through the heating zones and having one or more apertures, slots, nozzles or impingement tubes oriented in a predetermined configuration corresponding to known locations of the workpiece. The stations may be remotely controlled by an electronic control system.

The location and design of the nozzles, slots, etc. will depend on the size of the type of workpiece, including but not limited to: the actual distance the fluid medium needs to travel to impact the workpiece, the flow pattern design of the fluid medium, and other flow parameters.

In accordance with one aspect of the invention, at least one nozzle or other impingement device may have an opening with a diameter width of from about 1/8 inches to about 6 inches. In one aspect, at least one of the impingement devices has an opening approximately 1/8 inches wide. In another aspect, at least one of the impingement devices has an opening approximately 1/4 inches wide. In another aspect, at least one of the impingement devices has an opening approximately 3/8 inches wide. In yet another aspect, at least one of the impingement devices has an opening approximately 1/2 inches wide. In yet another aspect, at least one of the impingement devices has an opening approximately 5/8 inches wide. In yet another aspect, at least one of the impingement devices has an opening approximately 3/4 inches wide. In another aspect, at least one of the impingement devices has an opening approximately 7/8 inches wide. Other widths of the impingement device openings are also contemplated.

In yet another aspect, at least one of the impingement devices has an opening with a diameter width of less than about 1 inch. In another aspect, at least one of the impingement devices has an opening having a width of less than about 2 inches. In yet another aspect, at least one of the impingement devices has an opening having a width of less than about 3 inches. In yet another aspect, at least one of the impingement devices has an opening having a width of less than about 4 inches. In yet another aspect, at least one of the impingement devices has an opening having a width of less than about 5 inches. In another aspect, at least one of the impingement devices has an opening having a width of less than about 6 inches. Although specific impactor opening widths and width ranges are set forth herein, it should be appreciated that any suitable impactor diameter may be used to achieve suitable results in accordance with the invention. Accordingly, other opening diameters are also contemplated.

In accordance with another aspect of the invention, at least one nozzle or other impingement device may be positioned from about 0.5 inches to about 10 inches from the workpiece to impinge or blow fluid on and around the die, workpiece, and/or core. In one aspect, the at least one impacting device is from about 1 to about 8 inches from the workpiece. In another aspect, the at least one impacting device is from about 2 to about 6 inches from the workpiece. In yet another aspect, the at least one impacting device is from about 1.5 to about 3 inches from the workpiece. In yet another aspect, the at least one impacting device is from about 3 to about 7 inches from the workpiece. In another aspect, the at least one impacting device is from about 4 to about 9 inches from the workpiece. In yet another aspect, the at least one impacting device is from about 1 to about 4 inches from the workpiece. In yet another aspect, the at least one impacting device is from about 2 to about 5 inches from the workpiece. In yet another aspect, the at least one impacting device is from about 0.5 to about 6 inches from the workpiece. In yet another aspect, the at least one impacting device is from about 1 to about 4 inches from the workpiece.

For example, in one aspect, the at least one impacting device is about 10 inches from the workpiece. In another aspect, the at least one impacting device is about 9 inches from the workpiece. In yet another aspect, the at least one impacting device is about 8 inches from the workpiece. In yet another aspect, the at least one impacting device is about 7 inches from the workpiece. In another aspect, the at least one impacting device is about 6 inches from the workpiece. In yet another aspect, the at least one impacting device is about 5 inches from the workpiece. In yet another aspect, the at least one impacting device is about 4 inches from the workpiece. In another aspect, the at least one impacting device is about 3 inches from the workpiece. In yet another aspect, the at least one impacting device is about 2 inches from the workpiece. In yet another aspect, the at least one impacting device is about 1 inch from the workpiece.

In yet another aspect, the at least one impacting device is less than about 10 inches from the workpiece. In another aspect, the at least one impacting device is less than about 9 inches from the workpiece. In yet another aspect, the at least one impacting device is less than about 8 inches from the workpiece. In yet another aspect, the at least one impacting device is less than about 7 inches from the workpiece. In another aspect, the at least one impacting device is less than about 6 inches from the workpiece. In yet another aspect, the at least one impacting device is less than about 5 inches from the workpiece. In yet another aspect, the at least one impacting device is less than about 4 inches from the workpiece. In another aspect, the at least one impacting device is less than about 3 inches from the workpiece. In yet another aspect, the at least one impacting device is less than about 2 inches from the workpiece. In yet another aspect, the at least one impacting device is less than about 1 inch from the workpiece. Although various distances and distance ranges are provided herein, it should be appreciated that the impingement devices may be positioned as desired to achieve suitable results. Thus, a variety of other possible locations are also contemplated.

The fluid medium may be typically delivered to the workpiece at a discharge rate of from about 4000 to 40000 feet per minute (ft/min). In one aspect, the fluid medium is discharged from the impingement device at a velocity of from about 4000 to about 20000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of from about 8000 to about 25000 ft/min. In yet another aspect, the fluidic medium is discharged from the impingement device at a velocity of from about 6000 to about 15000 ft/min. In yet another aspect, the fluidic medium is discharged from the impingement device at a velocity of from about 15000 to about 30000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of from about 5000 to about 12000 ft/min. In a particular aspect, the fluid medium is discharged from the impingement device at a velocity of about 10000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of from about 7000 to about 13000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of from about 18000 to about 22000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of from about 9000 to about 14000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of from about 5000 to about 17000 ft/min.

In one aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 4000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 5000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 6000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 7000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 8000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 10000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 11000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 12000 ft/min. In another aspect, the fluidic medium is discharged from the impingement device at a velocity of at least about 13000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 14000 ft/min. In another aspect, the fluidic medium is discharged from the impingement device at a velocity of at least about 15000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 16000 ft/min. In yet another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 17000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 18000 ft/min. In yet another aspect, the fluidic medium is discharged from the impingement device at a velocity of at least about 19000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 20000 ft/min. In yet another aspect, the fluidic medium is discharged from the impingement device at a velocity of at least about 25000 ft/min. In another aspect, the fluid medium is discharged from the impingement device at a velocity of at least about 30000 ft/min. In yet another aspect, the fluidic medium is discharged from the impingement device at a velocity of at least about 35000 ft/min. It should be appreciated that although various speeds and speed ranges are provided herein, other speeds may be used to achieve suitable results in accordance with the present invention. Accordingly, a variety of other speeds and speed ranges are also contemplated.

The fluid medium may be delivered to the workpiece at a flow rate of typically about 50 to about 500 standard cubic feet per minute per foot of nozzle or other impingement device (scfm/ft). In one aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 50 to about 100 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 100 to about 150 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 150 to about 200 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 200 to about 250 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 250 to about 300 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 300 to about 350 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 350 to about 400 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 400 to about 450 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of from about 450 to about 500 scfm/ft. In one particular aspect, the fluid medium is delivered to the workpiece at a flow rate of about 250 scfm/ft.

In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 25 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 50 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 75 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 100 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 125 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 150 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 175 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 200 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 225 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 250 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 275 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 300 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 325 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 350 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 375 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 400 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 425 scfm/ft. In yet another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 450 scfm/ft. In another aspect, the fluid medium is delivered to the workpiece at a flow rate of at least about 475 scfm/ft. It should be appreciated that although various flow rates and flow rate ranges are provided herein, other flow rates may be used to achieve suitable results in accordance with the present invention. Accordingly, a variety of other flow rates and flow rate ranges are also contemplated.

The fluid medium may be delivered to the workpiece at a pressure of from about 3 to about 20 inches of water (in.wc). In one aspect, the fluid medium is supplied to the workpiece at a pressure of from about 5 to about 12in. In another aspect, the fluid medium is supplied to the workpiece at a pressure of from about 5 to about 8in. In another aspect, the fluid medium is supplied to the workpiece at a pressure of from about 9 to about 12in. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of from about 3 to about 6 in.wc.

In another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 3in. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 4in. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 5 in.wc. In another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 6 in.wc. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 7in. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 8 in.wc. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 9 in.wc. In another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 10 in.wc. In yet another aspect, the fluid medium is supplied to the workpiece at a pressure of at least about 11 in.wc. It should be appreciated that although various pressures and pressure ranges are provided herein, other pressures may be used to achieve suitable results in accordance with the present invention. Accordingly, a variety of other pressures and pressure ranges are also contemplated.

If desired, the fluid may be directed to a particular portion of the workpiece in order to position the fluid flow at a desired location. Additionally, the fluid may be directed to one or more faces of the workpiece as needed to improve the efficiency of impinging the fluid.

The workpiece or the impacting device, or both, may be vibrated, rotated, or otherwise moved randomly or at predetermined intervals to achieve additional fluid medium impacts, thereby increasing processing efficiency. The workpiece or the impact device may typically be moved at a rate or speed of up to about 40 ft/min. In one aspect, the workpiece or the impact device may vibrate, rotate, or otherwise move at a speed of from about 0.5 to about 5 ft/min. In yet another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 5 to about 10 ft/min. In yet another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 10 to about 15 ft/min. In another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 15 to about 20 ft/min. In yet another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 20 to about 25 ft/min. In yet another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 25 to about 30 ft/min. In another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 30 to about 35 ft/min. In yet another aspect, the workpiece or the impact device may be vibrated, rotated, or otherwise moved at a speed of from about 35 to about 40 ft/min. It should be appreciated that although various rates and ranges of motion are provided herein, other rates of motion may be used to achieve suitable results in accordance with the present invention. Accordingly, a variety of other rates and rate ranges are also contemplated.

The workpiece or the impacting device can be displaced a distance of, for example, from about 3 to about 36 inches in each direction of its travel when the workpiece and the impacting device are vibrated. In one aspect, the workpiece or impacting device is displaced a distance of from about 3 to about 5 inches in each direction of its travel. In another aspect, the workpiece or the impacting device is displaced a distance of from about 7 to about 10 inches in each direction of its travel. In yet another aspect, the workpiece or impacting device is displaced a distance of from about 10 to about 15 inches in each direction of its travel. In another aspect, the workpiece or the impacting device is displaced a distance of from about 15 to about 20 inches in each direction of its travel. In yet another aspect, the workpiece or impacting device is displaced a distance of from about 20 to about 25 inches in each direction of its travel. In yet another aspect, the workpiece or impacting device is displaced a distance of from about 25 to about 30 inches in each direction of its travel. In another aspect, the workpiece or the impacting device is displaced a distance of from about 30 to about 36 inches in each direction of its travel. Although various displacement distances are provided herein, it should be appreciated that the workpiece or impacting device may be moved any desired distance to achieve a suitable result, such as a distance substantially equal to the size of the workpiece. Accordingly, a variety of other displacement distances are also contemplated.

The time required for completing the shaking cycle can typically be from about 2 seconds to about 10 minutes. In one aspect, the shaking cycle is from about 5 seconds to about 1 minute. In another aspect, the shaking cycle is from about 2 to about 20 seconds. In yet another aspect, the shaking cycle is from about 20 to about 40 seconds. In yet another aspect, the shaking cycle is from about 40 seconds to about 1 minute. In another aspect, the shaking cycle is from about 1 to about 3 minutes. In yet another aspect, the shaking cycle is from about 3 to about 6 minutes. In yet another aspect, the shaking cycle is from about 6 to about 10 minutes. Although various vibration cycle times are provided herein, it will be appreciated that other vibration cycles may be used as desired to achieve suitable results. Accordingly, a variety of other vibration cycle times are also contemplated.

The temperature of the fluid medium used according to the invention may generally be from about 400 ℃ to about 600 ℃. In one aspect, the temperature of the fluid medium is from about 450 ℃ to about 550 ℃. In another aspect, the temperature of the fluid medium is from about 490 ℃ to about 540 ℃. In yet another aspect, the temperature of the fluid medium is from about 425 ℃ to about 600 ℃. In yet another aspect, the temperature of the fluid medium is from about 475 ℃ to about 575 ℃. In another aspect, the temperature of the fluid medium is from about 450 ℃ to about 500 ℃. In yet another aspect, the temperature of the fluid medium is from about 500 ℃ to about 550 ℃. Although specific temperatures are provided herein, it will be appreciated that other temperatures may be used as desired to achieve suitable results. Accordingly, a variety of other temperatures are also contemplated.

As shown in fig. 3, wherein the workpiece is formed in a sand mold with or without a core, a portion of the mold and/or core is released and dropped from the workpiece, for example, in a hopper 222 for subsequent recovery and reuse, as described above.

Referring to fig. 2, furnace 210 and/or aging furnace 212 may also include one or more "soak zones" 224a, 224b, 224c that utilize conventional air recirculation systems. For example, the furnace may include one or more heating zones followed by one or more soak zones. Fig. 5 shows an example of a "keep warm zone" with a conventional mass flow system having a baffle 226 and recirculation fan 228 system that can be used behind the heating zone.

Fig. 6-10 illustrate an alternative example of a casting post-treatment system 300 according to the present invention. The system of fig. 6 includes components according to the structure and function described in fig. 2-5, such as a plurality of furnaces 310, an aging furnace 312, and a cooler 313. However, the layout of the individual components is different from that in fig. 2.

The example system of FIG. 6 is shown with heating zones 314 and soak zones 316a, 316b, 316c, 316d, 316e in the heat treatment furnace 310 and heating zones 314a ', 314 b' in the aging furnace 312. The systems shown in fig. 6-10 may be used, for example, where the workpiece is formed without the use of sand molds, or the molds and cores are removed prior to entering the heat treatment furnace. When a sand mold collection hopper (such as element 222 shown in fig. 3) is not required, the system may include a hopper capable of receiving a workpiece formed from a sand mold.

It will be appreciated by those skilled in the art that although the invention has been shown and described in connection with a linear (straight line) flow furnace, other furnaces and ovens may be used. For example, as shown in FIGS. 11-14, the present invention may be used with a "rotating" processing system. As shown in fig. 11, the rotary furnace system 400 generally includes a heat treatment furnace 410 and an aging furnace 412, each of which includes a rotatable hearth 414, 414' for supporting and moving a workpiece 416. The furnace 410 generally comprises: an inlet opening 418, the inlet opening 418 in the peripheral wall 420 to enable the workpiece 416 to be placed into the furnace 410; and an outlet opening 422 in an inner peripheral wall 424. If desired, the inlet opening 418 may be adjacent a pouring station (not shown) to reduce heat loss during transfer to the furnace 410. Each rotary furnace and furnace may be connected to other rotary furnaces, or other processing stations by robotic means or other transport systems. In one aspect, a robotic device or transport system places components in set and/or aligned positions in each rotary furnace or furnace.

The workpieces are moved in the rotary heat treatment furnace 410 and the ageing furnace 412 by rotating the hearths 414a, 414b in the annular chamber. The hearth may rotate continuously or through indexing positions or may stop to receive or eject a component. Moreover, the hearth can be stopped to vibrate the workpiece (or nozzle) for a sufficient duration to enable the fluid medium to traverse the workpiece surface and to help make the process efficient.

To facilitate movement, the hearth is supported, for example, on wheels that run on circular rails below the hearth. The hearth is moved, for example, by a gear drive actuator that pushes or pulls along a planetary gear (ratchet mechanism) to the hearth. The drive mechanism may include a speed controller to regulate hearth movement to acceleration, normal operating speed and deceleration and may be used to vibrate the hearth to obtain additional fluid medium impingement on the component from the furnace and the furnace's internal nozzles. Seals may be disposed along the moving hearth and the inner and outer walls of the furnace to prevent heat or fluid leakage.

As shown in fig. 12 and 13, the movable hearth may include, for example, a rack or shelf system 426, 426' to enable multiple tiers of workpieces to be loaded and processed through the system. Once the workpieces are loaded into the shelving system, they are transported through the furnace on the shelving system in an angular (circular) motion (0 degrees up to 360 degrees) on a path concentric with the periphery of the furnace or ageing furnace. One or more pushers, actuators or drives may be used to move the rotary hearth.

The heat treatment furnace 410 and/or the aging furnace 412 may include one or more heating zones 428 and one or more soak zones 430. The heating and hold-warm regions may have a similar configuration to that described above, or may be constructed in any other suitable manner that allows the fluid to impinge directly on the respective workpiece. FIG. 12 illustrates a plurality of workpieces 432 in an exemplary heating zone 428 of the heat treatment or aging furnace 412 of FIG. 11. Air nozzles 434 are disposed in close proximity to the workpiece 432 to direct air or other fluid against the workpiece. FIG. 13 illustrates a plurality of workpieces in an example soak zone 430 of the heat treatment furnace 410 or the aging furnace 412 of FIG. 11.

Fig. 14a-14c illustrate another exemplary rotary heat treatment furnace that may be used in accordance with the present invention. The furnace 510 includes: an opening 512 through which a workpiece 514 enters and exits through the opening 512; and a rotatable hearth 516 for supporting the workpiece 514 and passing the workpiece 514 through the various zones until heat treatment is complete and the workpiece is removed. The furnace 510 shown in FIG. 14a includes a plurality of heating zones 518a, 518b, 518c, 518d, 518e, 518f, 518 g. As shown in FIG. 14b, each zone is similarly configured and includes a source of fluid (e.g., air) that is directed through a conduit 520 and impinges a portion of the workpiece 514, similar to the heating zones described above. However, one or more of the zones (e.g., zones 518a, 518b) may be operated at higher temperatures as needed to achieve suitable heat treatment results. As best shown in fig. 14c, the workpiece 514 may be arranged in a shelving system 522, such as the illustrated shelving system, wherein vertical 524 and/or horizontal supports 526 for the workpiece 514 are formed of a permeable material, such as a grid or mesh. In use, as fragments of the sand mould and/or core fall from the workpiece, the air flow sweeps these particles into the static fluidised bed for further combustion. Heat from the fluidized bed 528 is absorbed by the air system and used to impact the workpiece surface.

Optionally, the furnace and/or aging furnace includes features that enable the workpiece to be rotated and/or inverted so that each face or surface of the workpiece is closer to the conduit or nozzle. In addition, by inverting the workpiece, any loose sand and binder material (when used) can fall out of the workpiece.

In one aspect, the shelving or stacking system includes a rotating mechanism at least partially within the oven that includes clips or other mechanisms (not shown) mounted to the workpieces. The clip may be mounted on the post as required to prevent damage to the workpiece. The clamps may be mounted on a mechanism that causes the workpiece to be raised and inverted on the saddle. In this way, any loose sand from the core can fall off the workpiece. The workpiece may be rotated at certain times or at predetermined intervals to facilitate heat treatment and/or to remove cores from the workpiece.

In another aspect, the furnace includes at least one jaw or other grasping device for processing the workpiece. The jaws may include a plurality of mechanical "fingers" that contact and apply sufficient pressure to the workpiece to raise and manipulate the workpiece to position the workpiece in the furnace. Additionally, the jaws may include features that can grip and invert the workpiece to enable loose sand from the core to fall off the workpiece. The jaws may be used to grip the entire workpiece, or may be used to grip the workpiece through, for example, a vertical post. In use, the jaws may be provided with a feature to automatically grip onto the workpiece when the adhesive is burning and the die and core are dropped from the workpiece. The jaws may be robotic and may be programmed to move the workpieces one at a time for a suitable heat treatment time or temperature. Also or alternatively, the jaws may be manually operated by electronic controls so that an operator can manually manipulate a particular workpiece as desired.

In yet another aspect, the workpiece is placed in a saddle prior to entering the furnace. The saddle may generally be a basket or carrier formed of a metallic material having a bottom and a series of side walls defining a chamber or container into which the workpiece is loaded and in which the core hole or access opening is exposed. The saddle may include means for securing the workpiece so that the workpiece within the saddle can be rotated and inverted to allow loose core material to fall from the workpiece. The means for securing the workpiece may be any suitable means, such as a bracket, a clip, a tie, a strap, or any combination thereof. Other means for securing the workpiece in the saddle are also contemplated.

Optionally, in any of the aspects described or contemplated herein, a vibrating or vibrating mechanism may be provided to assist in further removing loose core material from the workpiece. In one variation, a vibration or vibration mechanism is disposed on the vertical post and above the workpiece to reduce or prevent damage to the workpiece.

Referring to fig. 11, when the workpiece 416 is ready to be removed, another robotic device or transport system may be used to transport the workpiece to a quenching station or cell 417, which quenching station or cell 417 may be located in a central open area 418 surrounded by the furnace 410 and proximate to the exit opening 422. In one aspect, the quench medium can be air delivered to the workpiece, for example at a velocity of from about 10 to about 500 feet per second (ft/s), such as about 200 ft/s. In another aspect, the quench medium can be water delivered to the workpiece, for example, at a velocity of up to about 50ft/s, such as about 10 ft/s. In yet another aspect, the quench media may still be water (at a velocity of 0 ft/s). In yet another aspect, a combination of quench media may be used. Other quench media and velocities are also contemplated.

After the quenching process is completed, another (or the same) robotic device 424 or conveyor system may be used to dispose the workpiece 416 in the rotary aging furnace 412, which rotary aging furnace 412 may also be located in a central open area surrounded by the furnace 410. The rotary ageing furnace 412 is similar to the rotary heat treatment furnace 410 except that the inlet and outlet openings 426, 428 may be on the same periphery (inner or outer wall). In addition, the diameter of the ageing furnace is generally smaller than the diameter of the furnace. However, the relative sizes of the rotary heat treatment furnace and the rotary ageing furnace may vary for a given application. For example, to accommodate an aging time that is longer than the heat treatment time (e.g., 30 to 60 minutes for heat treatment and 3 hours for aging), the perimeter of the rotary aging furnace may be longer than the rotary heat treatment furnace.

Another robotic device or transport system 430 may be used to remove the workpieces 416 from the aging oven 412 and place them into a cooling unit 432 in order to end the heat treatment process. The cooling unit blows around the work piece, for example with circulating air, as it moves through the chamber on a roller hearth or belt conveyor. Cooling continues until the temperature of the workpiece is sufficiently reduced for processing by factory personnel. In one aspect shown in fig. 11, the cooling unit 432 is open near the aging furnace 412 and can move along a spiral path outside the rotary heat treatment furnace such that the outlet 434 is outside the circumferential wall of the rotary heat treatment furnace 410. The direction of travel of the cooling unit may be spiraled downward (downward) or upward (upward) from the rotary heat treatment furnace, as desired. For example, the cooling unit is shown as defining a curved downwardly spiraling path from the interior of the furnace to the exterior.

Optional sand reclamation feature

As previously mentioned, when sand molds and/or cores are used, the sand may be removed and recovered at various points throughout the process. Sand washers may also be used to remove ash particles or other foreign particles from the sand prior to reuse. Examples of Sand reclamation systems are provided in U.S. patent nos. 5350160, 5565046, 5738162 and 5829509 and U.S. patent application No.11/084321 (entitled "system for Heat Treating Castings and Reclaiming Sand," 3/18/2005), each of which is incorporated herein by reference in its entirety. Examples of other systems for heat treating castings, removing sand cores, and reclaiming sand are provided in U.S. patent nos. 5294094, 5354038, 5423370, 5829509, 6336809, and 6547556, each of which is incorporated herein in its entirety by reference.

A particular example of a sand reclamation system is described in detail below. However, any recovered sand recovery and/or sand wash system may be used in various aspects of the present invention. Moreover, the method and system for recovering refined sand may be implemented independently, or may be integrated into other metal processing components, such as heat treatment furnaces, coring units, and the like.

FIG. 15 illustrates one example of a system and method for reclaiming sand that may be used in various aspects of the present invention. In one example, the sand reclamation chamber or unit may include a heated fluidized bed having a plurality of baffles and/or weirs defining a passageway through which the spent sand travels. As the waste sand travels along the path, the binder burns and the sand refines. The number and length of baffles, flow rate through the fluidized bed, temperature, and other system variables may be determined to allow the sand to be refined to a suitable degree.

The system 600 includes a chamber 610 having an inlet 612 and an outlet 614. Waste sand W is supplied to the chamber through the inlet. The spent sand may be charged directly from another processing unit or step or may be collected and stored prior to reclamation. For example, the waste sand W may be stored in a sand reservoir 616, which sand reservoir 616 is designed to receive and store dry, mostly granulated, waste sand from the sand system of the plant. The reservoirs may have various specifications and characteristics. For example, the waste sand storage tank may be a cylindrical box about 10 feet in diameter and having straight sides about 18 feet long, which is capable of storing about 45 tons of sand. The reservoir may be designed with an anti-segregation feature (not shown), such as a chamber or baffle, that reduces or eliminates the segregation and drainage of non-uniform grit distribution. The reservoir may include a top guardrail, an access port, a sand receiving flange, a discharge flange, an internal safety ladder, a top inlet, and a sand level indicator (not shown). The means 618 for draining from the reservoir 616 may include a maintenance slide gate and a double flap valve metering device (not shown). The waste sand may be metered from the waste sand storage tank at a suitable rate, for example, equal to about 20 tons per hour.

The chamber 610 has a heating element to burn the binder material contained in the waste sand. Any heating element (e.g., a radiating element) may be used to provide heat to the system. Typically, the temperature of the fluidizing medium is maintained at or above the combustion temperature of the binder, typically from 250 ℃ to about 900 ℃. Thus, in this and other aspects, the temperature of the fluidizing medium can be from about 490 ℃ to about 600 ℃. The binder is combusted and the sand is refined as the fluidized spent sand particles move along a circulation path defined by a plurality of baffles and (optional) weirs. The circulation path may be of any length as required to achieve suitable results. For example, in this and other aspects, the length of the passageway can be from about 5 meters to about 15 meters, such as about 10 meters. A fluidizing air distributor (not shown) may be used to improve the uniformity of the fluidizing medium flow. Also, the particles may be utilized, for example, at about 2300Nm³A fluidizing blower (not shown) operating at a flow rate/h is passed through the shell. The spent sand has a residence time in the chamber that is substantially sufficient for refining, cleaning, and other recovery of the sand before it exits the chamber through the outlet. For example, in this and other aspects, the residence time in the chamber can be from about 30 minutes to about 60 minutes. The substantially refined sand R may be collected or stored in any manner known to those skilled in the art. In this and other aspects, the system mayFrom about 10 tons/h to about 20 tons/h of refined sand, for example about 15 tons/h of refined sand, are manufactured.

As another example, an integrated core extraction and reclamation system may be provided. The system includes a coring unit including at least one chamber through which the castings are moved for recovering the sand cores from the castings. Any method of scoring, breaking, chiseling, shredding, etching, sandblasting or removing (collectively "taking out") the core may be suitably used, for example, the methods described in U.S. patent nos. 5565046, 5957188 and 5354038, each of which is incorporated herein in its entirety.

When the core is removed from the casting, the waste sand fragments are gravity fed or otherwise directed to a sand reclamation chamber. The sand reclamation chamber includes: a fluidized bed in fluid communication with the coring unit; and a plurality of baffles defining a circulation path through the fluidized bed. The fluidised bed is heated to or above the combustion temperature of the binder. As the sand moves along the circulation path, the binder burns and the sand refines. The refined sand may be collected and stored in any manner known to those skilled in the art.

Alternatively, waste sand from the sand reservoir may also be provided to the recovery system for disposal simultaneously with waste sand produced by coring.

FIG. 16 illustrates an example integrated coring and sand reclamation system wherein the coring unit includes a furnace. Optionally, the system 620 includes a waste sand reservoir 616, the waste sand reservoir 616 being in fluid communication with an inlet 622 of a furnace 624. The furnace 624 defines at least one heating chamber through which castings (not shown), such as engine blocks and cylinder heads, are passed for heat treatment, sand core material removal and sand reclamation. The waste sand W charged to the furnace 624 from the waste sand storage tank 616 can be cleaned, reclaimed, and otherwise refined in the chamber and directed through the outlet 626 for storage or further processing. In addition, when the waste sand is produced by a coring process, it may also be processed through a sand reclamation system. Alternatively, some or all of the waste sand produced by the coring process may be collected and stored for later disposal.

The system 620 may include a calciner 628 in fluid communication with the chamber of the furnace 624. The system 620 may further include: a heat exchanger 630, the heat exchanger 630 being in fluid communication with the calciner 628; a pressurized air source 632; and the chamber of furnace 624. The heat from the calciner 628 may be used to heat the pressurized air and/or to heat the chamber interior of the furnace 624.

Referring to fig. 17-19, the furnace 624 may include supplemental pressurized air distributors 634 and/or heating elements such as radiant tube heaters 636. The radiant tube heaters 636 are located below the roller hearth 638 on which the castings 640 are conveyed through the furnace 624. One or more weirs and baffles 642 are disposed in a bottom portion of the furnace 624 and within the fluidized bed 644 region. The deflector 642 defines a circulation path through which the spent sand must travel in order to exit through the sand outlet 626. The spent sand is retained in the furnace 624 for a time sufficient to refine, clean, and otherwise recover the spent sand before it exits the furnace 624. In One aspect, the furnace 624 is a Number One or Number Two Sand Red ion ® bottom furnace module available from consistent Engineering Corporation of Kennesaw, Georgia. However, it should be appreciated that any other suitable furnace may be used in accordance with the present invention.

The fluidized heating system disposed in the furnace 624 includes one or more heating elements 646, which are represented in fig. 17-19 as radiant heating tubes. The heating elements 646 supplement heat into the heating zones of the furnace 624 and at least partially compensate for heat loss during the opening of the furnace door and the addition of the cooler castings 640. The fluidized heating system may also radiate heat directly to the bottom casting 640. In general, the fluidization temperature may be the same as the furnace heating temperature. The fluidization system can also include a fluidization blower (not shown) to provide pressurized air to the fluidization distributor 634.

The furnace exhaust air calciner 628 (fig. 16) may be any suitable calciner, as known to those skilled in the art. For example,the calciner may be operated at about 825 c for a residence time of about 1.0 second in order to burn the carbon monoxide and volatile organic compounds to acceptable levels for venting to the atmosphere. In one aspect, the calciner 628 has about 6800Nm³The capacity of H. In another aspect, the calciner 628 comprises a sidewall insulation of 1260 ° ceramic fibers approximately 200mm thick. In another aspect, the calciner 628 comprises: a top mounted burner having a gas train and a controller; an observation door; as well as other features known to those skilled in the art. Internal mixing baffles, inlet type plates, or combinations thereof may be used to obtain sufficient velocity and turbulence in the calciner.

Likewise, heat exchanger 630 can be any suitable heat exchanger, as known to those skilled in the art. The heat exchanger 630 may utilize heat from the calciner 628 to at least partially heat the air to be used in the fluidization system. Hot dust laden gas is generally fed from the calciner connection duct 648 to the heat exchanger 630 and is discharged through a discharge duct. In one aspect, the heat exchanger 630 is a U-shaped heat exchanger with overall dimensions of about 4000mm by 2100mm in height. In another aspect, the housing of the heat exchanger is a steel plate with structural steel supports, as well as other suitable materials. In another aspect, the insulation of the heat exchanger is castable MC25 with 75mm mineral wool, while the top insulation is a ceramic fiber module. In yet another aspect, the front row of heat exchanger tubes is formed of Incoloy 800HT and the remaining rows SA-249-304L are formed of stainless steel. The tube may be 35mm OD with an average wall thickness of 2.1 mm. The process air tube bundle top manifold may be a 6mm thick combination of 304 stainless steel and carbon steel.

The recovered sand R is discharged from the outlet 626 to the hot sand inclined conveyor 650. The system 620 can produce from about 3 to about 10 tons/h of sand, e.g., 5 tons/h, from the sand core material removed from the castings being processed in the furnace 624 and from about 5 to about 15 tons/h of waste sand, e.g., about 10 tons/h, from the waste sand from the storage 616, so that the overall production rate is from about 10 to about 20 tons/h of refined sand, e.g., about 15 tons/h.

The recovered sand may be combined with other sand in a downstream processing unit where the sand is pre-screened, fine screened, and cooled. The various post-recovery steps may have a total capacity of from about 10 to about 20 tons/h, for example 15 tons/h.

Example 1

The time required for the various furnaces to reach the predetermined temperature was evaluated. The results are shown in tables 1 and 2

TABLE 1

Operation of	System for controlling a power supply	Description of the invention	Approximate time to 932F
				1	Sand Lion ® furnace (Dock Module)	Single-hearth roller hearth Sand Lion ® furnace with a 38 inch vertical axis CEC axial fan mounted on the top, airflow through the load and up the sides, vertical radiant tubes mounted on the top in the return air, and a tilted floor with hot air fluidizer	75min
2	DFP (Small test DFB)	Sand bed of about 3 cubic feet with hot air fluidizer	60min
				3	HP furnace	A single-tier roller hearth, Sand Lion ® furnace, top-mounted 40 inch vertical axis radial flow fans, air flow directed through side plenums to nozzles above and below the load, with a nozzle discharge velocity of approximately 10000 feet per minute, two side-mounted direct fired burners discharging to the fan inlet,	40min

		inclined floor with hot air fluidizer
				4	Experimental furnace-approximately closed Heat treatment (CPHT) furnace	The individual casting unit has one nozzle above and below the casting, a 26 inch long slot nozzle located about 2 inches from the casting, a nozzle discharge velocity of about 10000ft/min, the casting capable of vibrating below the nozzle, the casting arranged with a downward plate and upward vertical posts, an external heater box for heating the nozzle air to a desired temperature, and a unit internal dimension of about 3 cubic feet	35min

TABLE 2

Operation of	System for controlling a power supply	Approximate time to 1000 ° F
			5	HP furnace	60min
6	Experimental CPHT furnace	40min

Example 2

The effect of various parameters on the time required for coring was evaluated, manufacturer A2 valve 1-4 cylinder head castings (with the mold intact). The CPHT furnace described in example 1 was used at a set point of 1000F. The results are shown in tables 3 to 5.

TABLE 3 influence of nozzle air flow Rate

Operation of	Air velocity (scfm)	Core taking time (min)
			7	620	35
8	300	100
			9	450	45

TABLE 4 influence of nozzle vibration

Operation of	Vibration	Core taking time (min)
			10	The casting was vibrated at about 14 feet per minute in a direction perpendicular to the length of the nozzle for about 12 inches	35
11	Without vibration	60

TABLE 5 influence of nozzle number and position

Operation of	Nozzle structure	Core taking time (min)
			12	Two nozzles-each nozzle having an opening of 1/3 inches in diameter, approximately 620scfm	35
13	Only the upper nozzle, 1/3 inch diameter opening, was approximately 469scfm	80
			14	Alternate upper and bottom plates every 5 minutes-each with 1/3 inch diameter openings, approximately 469scfm	45

Example 3

The effect of temperature on the time required to core various workpieces was evaluated using the CPHT furnace described in example 1. The results are shown in Table 6

TABLE 6

Operation of	Cylinder head	Furnace temperature set point (F.)	Core taking time (min)
				15	Manufacturer A2 valve I-4	914	60
16	Manufacturer B4 valve V-6	914	110
				17	Manufacturer A4 valve I-4	914	135
18	Manufacturer A2 valve I-4	932	60
				19	Manufacturer C diesel 4 valve	932	200
20	Manufacturer A2 valve I-4	1000	35
				21	Manufacturer B4 valve V-6	1000	60
22	Manufacturer A4 valve I-4	1000	80
				23	Manufacturer C diesel 4 valve	1000	160

Example 4

Various process conditions were evaluated using the CHPT furnace described above. First, the sample cylinder heads (including cores) were weighed and two different types of cylinder heads were evaluated. Type R is a 4-valve I-4 diesel cylinder head from manufacturer D. Type S is manufacturer D4.6L 4 valve cylinder head. The thermocouples are mounted on each workpiece. A plurality of holes having a diameter of 1/4 inches (25mm) were drilled to facilitate coring. Each workpiece was preheated in the CPHT unit to a temperature of approximately 662F (except for operation 30, which operation 30 was not preheated).

Then, each workpiece was heat-treated (raised) for 40 minutes (except for operation 28, it was heat-treated for 60 minutes). The furnace set point was about 923F (495℃.).

The workpiece is then quenched to 176 ° f (80 ℃) in about 12 minutes (or less), removed from the quenching unit, and operated to remove any remaining loose sand. Loose sand was collected, weighed and evaluated for appearance. The casting is then repeatedly slammed (bumped) with a hammer to dislodge and remove any core sand that may remain in a plurality of bonded states. Again, the removed sand was collected, weighed and evaluated for appearance. The results are shown in Table 7.

Table 8 shows additional data for operations 26-30. When viewing table 7, it was found that workpieces having a greater percentage of clean openings according to the present invention were able to achieve greater core removal (table 7).

Additionally, for some runs, the hardness of each workpiece is imparted to the material at one or more locations on each cylinder head. The results are shown in Table 9.

TABLE 7

Operation of	Workpiece	Initial weight wt (lb) (kg)	Loose sand wt (Ib) (kg)	Appearance of the product	Knock sand wt (lb) (kg)	Appearance of the product	Final work wt (Ib) (kg)	Nozzle distance (in.) (upper) (lower)	Core wt (lb) (kg)	Residual core (%)	Core taken out (%)
												24	R	83.6037.90	0.220.10	99% clean 3 glue block	0.620.28	90% black soft block	61.9528.11	3.132.63	21.659.79	2.86％2.86％	97.14％97.14％
25	R	85.6038.84	0.360.17	95% clean rubber block	2.000.91	100% black soft and hard block	62.3528.29	3.132.63	23.2510.55	8.60％8.63％	91.40％91.37％
												26	S	91.9041.68	0.300.14	96% clean	0.080.03	100% black small quantity intermediate hard block	61.4527.88	3.132.63	30.4513.80	0.26％0.22％	99.74％99.78％
27	S	91.7041.60	0.320.14	86% clean	0.160.08	100% black few very soft and hard blocks	61.7028.00	3.132.00	30.0013.60	0.53％0.59％	99.47％99.41％
												28	S	91.9541.70	0.460.21	98% clean	0.160.07	55% black few very soft and hard blocks	61.2527.80	3.132.00	30.7013.90	0.52％0.50％	99.48％99.50％
29	S	90.3040.96	2.20	85% clean	0.000.00		60.7527.56	3.132.00	29.5513.40	0.00％0.00％	100％100％
												30	R	93.0042.18	0.040.01	80% clean	3.70	60% black	60.8027.60	3.132.00	32.2014.58	0.01％0.03％	99.99％99.97％
31	R	83.9038.06	0.380.17	90% clean	1.920.87	100% black soft and hard block	62.1028.18	3.132.00	21.809.88	8.81％8.81％	91.19％91.19％
												32	R	86.0539.04	0.200.09	95% clean	1.800.82	100% black soft block	61.6027.96	3.132.00	24.4511.08	7.36％7.40％	92.64％92.60％
33	S	91.4541.48	0.300.13	80% clean	0.860.39	98% black soft and hard block	61.2027.77	3.132.63	30.2513.71	2.84％2.84％	97.16％97.16％

TABLE 8

Operation of	Intake valve (% open) (% closed)	Exhaust valve (% open) (% closed)	Inner water jacket (6) (% open) (% closed)	Exterior partWater jacket (10) (% open) (% closed)	Total average (% open) (% closed)	Mean valve open (% open) (% closed)	Mean water jacket (% open) (% closed)
								26	1000	1090	1684	8515	5347	5545	5150
27	1000	3862	1783	1000	6436	6931	5942
								28	6337	2575	3367	5050	4357	4456	4259
29	1000	1000	1000	1000	1000	1000	1000
								30	1000	1000	1000	1000	1000	1000	1000

TABLE 9 hardness (HBW 10/50 (Brinell 10mm ball 500kg load))

Operation of	Position 1	Position 2	Position 3	Position 4	Position 5	Position 6
							24	92.6	-	-	-	-	-
25	87.0	85.7	-	-	-	-
							26	79.6	96.3	91.1	89.0	92.6	89.0
27	96.3	96.3	96.3	96.3	96.3	96.3
							28	92.6	96.3	96.3	96.3	100	98.6
29	85.7	92.6	96.3	100	100	96.3
							30	89.0	100	92.6	89.0	92.6	92.6
31	85.7	-	-	-	-	-
							32	85.7	-	-	-	-	-

Thus, it will be appreciated by those skilled in the art that, in view of the foregoing detailed description of the invention, the invention is susceptible to broad use and utilization and that various modifications, changes, and equivalent arrangements, which differ from those described herein, may be apparent, without departing from the spirit or scope of the invention.

Although the present invention has been described in detail with respect to particular aspects, it should be understood that the detailed description is merely exemplary of the present invention and is provided for purposes of illustration only and description. The detailed description set forth herein is not intended to limit the invention or otherwise exclude other such embodiments, adaptations, variations, modifications and equivalent arrangements of the present invention, which is limited only by the claims appended hereto and the equivalents thereof.

Claims (17)

1. A furnace for heat treating a workpiece, comprising:

at least one high pressure heating zone comprising at least one fluid impingement device capable of directing a heated fluid medium toward a workpiece in a furnace, wherein the fluid impingement device is less than about 6 inches from the workpiece.

2. The furnace of claim 1, wherein: the fluid impingement device is less than about 4 inches from the workpiece.

3. The furnace of claim 1, wherein: the fluid impingement device is about 2 inches from the workpiece.

4. The furnace of claim 1, wherein: at least one of the fluid impacting device and the workpiece is capable of vibrating at predetermined intervals.

5. The furnace of claim 1, wherein: the fluid impingement device is capable of directing the heated fluid medium toward the workpiece at a velocity of about 4000 feet per minute.

6. The furnace of claim 1, further comprising: at least one of a rotation mechanism for rotating the workpiece and a gripping mechanism for inverting the workpiece.

7. The furnace of claim 1, further comprising: at least one hold-warm zone comprising an air recirculation system downstream of the high pressure heating zone.

8. A furnace for heating a workpiece, comprising:

at least one high pressure heating zone comprising at least one fluid impingement device capable of supplying a heated fluid medium at a rate of from about 4000 to about 40000 feet per minute; and

at least one insulated zone, the at least one insulated zone including an air recirculation system.

9. The furnace of claim 8, wherein: the fluid impingement device may be capable of supplying the heated fluid medium at a rate of about 8000 to about 12000 feet per minute.

10. The furnace of claim 8, wherein: at least one of the fluid impacting device and the workpiece is capable of vibrating at predetermined intervals.

11. The furnace of claim 8, wherein: the impingement unit is a nozzle fed through a system of channel ducts.

12. The furnace of claim 8, further comprising: at least one of a rotation mechanism for rotating the workpiece and a gripping mechanism for inverting the workpiece.

13. A system for processing a metal workpiece, comprising:

a heat treatment station comprising a furnace comprising at least one high pressure heating zone comprising at least one fluid impingement device capable of directing a heated fluid medium toward a workpiece in the furnace; and

a quench station located downstream of the heat treatment station.

14. The system of claim 13, further comprising: a process control temperature station located upstream of the heat treatment station, the process control temperature station comprising a temperature sensing device in communication with a heat source, wherein the temperature sensing device and the heat source are in communication to maintain the temperature of the workpiece at or above a process control temperature of the metal of the workpiece.

15. The system of claim 14, wherein: the process control temperature is a temperature at which, for each minute of time, the temperature of the workpiece is reduced below the temperature, an additional heat treatment of more than one minute is required to obtain the desired characteristics of the workpiece.

16. The system of claim 13, the furnace comprising: an inlet region for a workpiece;

a temperature measuring device in the inlet region; and

a transport mechanism in communication with the temperature measurement device;

wherein the transport mechanism removes the workpiece before the workpiece enters the furnace when the temperature measuring device detects the removal temperature.

17. The system of claim 13, further comprising a sand reclamation system comprising:

a chamber comprising an inlet, an outlet, and a plurality of baffles defining a circulation path therebetween for sand;

a heating element for providing heat to the chamber; and

a fluidizing air distributor for forcing the sand through the chamber.