US2683938A - Device for cooling casting sand - Google Patents

Description

y 1954 K. A. G. GUSTAVSSON 2,683,938

DEVICE FOR COOLING CASTING SAND Filed Dec. 26, 1952 2 Sheets-Sheet 1 July 20, 1954 K. A. cs. GUSTAVSSON DEVICE FOR COOLING CASTING SAND Filed Dec, 26, 1952 2 Sheets-Sheet 2 Gwr/n/ssom MMM HM ,QrraR/vEY P otented July 20, 1954 UNITED th s? FFIQE DEVICE FOR GOOLING CASTING SAND Application December 26, 1952, Serial No. 328,029

Claims priority, application Sweden September 9, 1952 11 Claims.

The present invention relates to a device for cooling casting sand, as is used in foundries, by a flow of a gaseous cooling fluid such as air.

The problem cooling the casting sand which is used for melding of cores is an important one in foundries which frequently use very large quantities of casting sand, sometimes many tons per hours.

Accordingly, it is the principal object of the present invention to provide a device for rapidly and effectively cooling the sand. As will be evident, a rapid and eifective cooling of the casting sand has the advantage of substantially reducing the quantity of sand which must be kept in a foundry for carrying out the casting operations. A reduction of the total quantity of sand in turn entails other advantages such as reduced requirements of space and transportation, etc.

A new preferred embodiment of a device for cooling casting sand by means of a flow of a gaseous cooling fluid comprises guide means for imparting to a. fluid current directed through the guide means an inwardly spiraling rotation in a substantially horizontal plane, the said guide means including fluid inlet means disposed at the periphery of said guide means and fluid outlet means disposed at the center of said guide means. The device further comprises feeding means for feeding sand to be cooled into a fluid current inwardly spiraling through said guide means, the said feeding means bein disposed intermediate to the periphery and the center of the guide means preferably closer to the center thereof, thereby to the comparatively heavy particles of end an outwardly spiraling rotation tow periphery of the guide means, and downwardly open discharge means at the periphery of the guide neans for discharging by the force of gravity particles of sand reaching the periphery of the guide means. Consequently, the particles of sand moving through the fluid current in counters rrent thereto are effectively cooled when they reach the discharge means.

C ther objects, features and advantages of the invention will he pointed out hereinafter and set forth in the appended claims forming part of the application.

In the accompanying drawing a now preferred embodiment of the invention is shown by way of illustration not by way of limitation.

In the drawing:

lg. l is an elevational sectional view of a sand cooling device according to the invention, and

Jig. 2 is a top view of- Fig. 1.

Referring now to the figures in detail, the exemplified cooling device comprises a vertically disposed housing composed of an upper substantially cylindrical part l and a lower substantially conical or funnel-shaped part 2. The lower end of housing part 2 forms the discharge end of the housing and is extended by a discharge conduit 3. Housing part I is substantially closed by a top wall 4. Below this wall and parallel thereto, a horizontal plate 5 is mounted. As will be apparent, plate 5 divides the housing in an upper compartment i9 ab vs the plate and a lower compartment below the plate. The plate is formed with a central opening which communicates with a conduit pipe 5 which should be visualized as connected to the suction side of a pump (not shown). As a result, the opening in plate 5 constitutes a suction mouth in which is fitted a mouthpiece i so rounded that a current of a cooling fluid such as air does not experience an abrupt change in direction when sucked through conduit 6.

The sand to be cooled is fed into the upper compartment it of the housing by feeding means disposed above the top wall t of the housing. These feeding means are shown as comprising a funnel-shaped hopper 3 below the discharge end of which a rotary horizontal distribution disc IE! is mounted. This disc may be rotated by any suitable means such as a motor Si and is spaced from the discharge end of hopper by a space i l the volume of which is so se ected that a suitable quantity of sand is fed upon disc it. The sand accumulating upon disc it is thrown outwardly by the centrifugal force acting upon the sand when disc it is rotated. The feeding means further coin rise a plurality of inlet members It shown as funnels communicating with the upper compartment is of the housing through openings Hi. The funnels it and their inlet openings i i are circumferentially spaced about the periphcry of disc it and situated on a circle intermediate to the central opening of plate 5 and the periphery of the plate, preferably closer to the center of the plate. To facilitate the distribution of sand accumulating on the outer part of disc is a plurality of wipers it are preferably provided which serve to wipe the sand on disc it into funnels !3.

The fluid inlet means for imparting to the gas current an inwardly spiraling rotation are disposed above the top wall t of the housing encompassing the hereinbefore described feeding means. The inlet means are shown as compris. ing guide means including a channel in form of a single winding following the peripheral outline of housing part I as can best be seen on Fig. 2. The cross-section of this channel decreases from its intalie mouth l6 toward its outlet end H for instance by reducing the height of the channel above wall member 2- from a maximum height at the intake end [6 to a minimum height at the outlet end ll; the height at that latter end may be practically zero. Channel [5 communicates with the upper compartment i9 of the housing through a peripheral annular slot 18 in wall 4.

The upper compartment 153 communicates with the lower compartment of the housing and hence the discharge conduit 3 by an annular slot 23.

The device further comprises a rotary horizontal disc 2i disposed below the discharg end of conduit 3 and rotatable by any suitable means such as a motor 22. Sand accumulating upon disc 2| is preferably wiped off by means of a wiper 23 and swept into a chute 24.

The device for cooling of foundry sand, as hereinbefore described, operates as follows:

Let it be assumed that a current of air is suciied through conduit 6. The air enters the device at the intake opening iii and experiences a rapid acceleration by the decrease in height of the channel it and is also forced to follow a substantially circular orbit owing to the configuration of channel it. When the air current now enters compartment l9 through slot IE it retains its rotary motion by reason of its inertia. It further performs an inwardly spiraling motion within compartment l9 by reason of the centrically located discharge opening in plate 5.

The sand to be cooled is fed into hopper 8 out of which it falls upon disc H and is swept by wipers i2 into the distribution funnels !3. As soon as the particles of sand enter the compartment it they are subjected to the influence of the air current inwardly spiraling therein. When now a suitable relation, easily ascertainable by trial and calculation, between the rotational velocity of the air current and the quantity and size of the particles of sand is maintained, the particles of sand are carried along by the spiraling air current. However, by reason of the high specific weight of the sand particles relative to the specific weight of the air and the strong influence of the centrifugal force the particles will not spiral toward the center of rotation of the air current but outwardly that is toward the periphery of compartment l9 or plate 5. As soon as they reach this periphery, they will fall by the force of gravity which now overcomes the centrifugal force through slot 29 into the lower compartment of the housing formed substantially by housing part 2. Finally, the particles of sand are discharged through conduit 3 and swept by wiper 23 into chute 24.

It will be apparent from the previous description that the radial component of movement of the particles of sand is opposite to the radial component of movement of the air current, In other Words, the particles of sand pass through compartment it in countercurrent to the airflow. Consequently, the sand is eil'ectively and rapidly cooled during its passage through compartment l9. At the same time any moisture adhering to the particles of sand is dissipated.

While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A device for cooling casting sand comprising in combination, a housing, guide means for imparting to a gaseous flow of a cooling fluid directed through said guide means a centripetally spiralling rotation in a horizontal plane, the said means including a circular guide plate horizontally mounted within the housing spaced therefrom by a peripheral slot and dividing the housing in an upper and a lower compartment, fluid inlet means communicating with the upper compartment and disposed at the periphery of said guide plate and fluid outlet means communicating with the upper compartment and disposed at the center of said guide plate for producing said centripetally spiralling fluid flow within the upper compartment, feeding means for feeding sand to be cooled into the fluid flow centripetally spirally through said upper compartment, the said feeding means being disposed intermediate to the periphery and the center of the guide plate thereby imparting to the particles of sand, by the centrifugal force actuating upon said particles, a centrifugally spiralling rotation toward the periphery of the uide plate, the said peripheral slot connecting the upper compartment with the lower compartment for exhausting from the upper compartment, by the force of gravity, particles of sand reaching the periphery of the guide plate into the lower compartment, the said particles of sand being cooled by outwardly moving through the upper compartrnent in countercurrent to the centripetally spiralling fluid fiow.

2. A device for cooling casting sand comprising in combination a housing closed by a top wall, a circular guide plate horizontally mounted within the housingso as to divide the housing in an upper and a lower compartment and formed with a central opening and a discharge opening radially spaced from said central opening, a conduit communicating with said central opening and adapted to be connected with suction pump means, inlet means for admitting a gaseous cooling fluid into the upper compartment of said housing, the said inlet means communicating with said upper compartment through an open ing in the top Wall of the housing near the periphery thereof and including fluid guide means having an open intake end and shaped so as to impart to a gaseous fluid sucked through said guide means and into the upper compartment of the housing a rotational motion inwardly spiraling toward the central opening of said plate, and feedingmeans for feeding sand into the upper compartment of said housing, the said feeding means communicating with said upper compartment at a point intermediate to the center opening of said plate and the periphery of the plate whereby an outwardly spiraling motion is imparted to particles of sand fed into said upper compartment, the said particles being discharged into the lower compartment of the housing through said discharge opening after being cooled by movingin a countercurrent to said fluid current.

3. A device according to claim 2, wherein the said fluid guide means of the inlet means comprise a casing defining a channel in form of a winding disposed above said housing and decreasing in cross-section from said open intake end toward the end of said winding, the said channel communicating substantially along its entire peripheral length with said upper compartment by an annular peripheral slot in said top wall of the housing.

4. A device according to claim 2, wherein the said feeding means comprise a rotary distribution disc, and a plurality of sand inlet members leading into said upper compartment and disposed in a spatial relationship relative to said disc in which sand fed upon said disc is directed toward said inlet members upon a rotation of said disc.

5. A device according to claim 4, wherein wiper means are mounted above said disc in coaction with the same for wiping off sand accumulating upon said disc.

6. A device according to claim 5, wherein a feed hopper is disposed above said disc for feeding sand upon the same.

7. A device according to claim 6, wherein the said inlet members are in form of funnels circumferentially spaced about said disc.

8. A device according to claim 2, according to claim 4, wherein the lower compartment of said housing is substantially funnel-shaped in downward direction, said upper compartment communicating with said lower compartment by an annular slot formed between the periphery of said plate and the outline of said housing, the said slot forming the discharge opening of said horizontal plate.

9. A device according to claim 2, wherein a discharge conduit is connected with said lower compartment of the housing.

10. A device according to claim 9, wherein a rotary sand distribution disc is disposed below the outlet end of said discharge conduit.

11. A device according to claim 10, in combination with Wiper means coactingwith said disribution disc for wiping off cooled sand accumulating upon said disc.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,157,935 Gray Oct. 26, 1915 1,989,406 Doolittle Jan. 29, 1935 2,028,413 Sackett Jan. 21, 1936 2,287,795 Hall June 30, 1942 2,602,242 Dok July 8, 1952 FOREIGN PATENTS Number Country Date 114,810 Sweden Sept. 11, 1945

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