CN1062056C - Box type screw compressor - Google Patents

Abstract

The compressor, accelerator, and main motor are all mounted on the base, while the intercooler, aftercooler, lubricating oil cooler, and coolant cooler are all installed perpendicular to the motor's axis, aligning their installation orientation with the direction of extraction of the gas cooler tube bundle. The control panel with the operator interface is mounted on a front panel consisting of two sections, which are mounted so that they can rotate about opposing or displaced sides. Sections requiring daily inspection are located near the front panel and on a side panel adjacent to it.

Description

Box type screw compressor

The present invention relates to a box-type complete screw compressor, which is equipped with a compressor body, a motor and auxiliary equipment, and these components are installed in its box. The above-mentioned type of compressor is used, for example, as an oil-free air source for general industrial equipment . Furthermore, the invention relates to the coating of screw rotors of dry screw compressors. The gas compressed by the compressor may be air or a gas other than air.

The traditional small packaged screw compressor is made into a box-shaped structure, which is equipped with a noise-proof cover to cover all the equipment to avoid noise. This type of compressor is published, for example, in "Energy Saving Clean Air System-Application of New Type Oil Free Screw Compressor" (Hitachi Review Vol. 65, No. 6 (1983) P. 19-24). As shown in Figure 15, the compressor 200 of the above-mentioned type is configured such that all the components required for the operation of the compressor 200 are mounted on a common base 201 and covered with a noise insulation cover 209: the main motor 202; Low-pressure and high-pressure stage screw compressor main bodies 204 and 205, which are driven by the motor 202 through the accelerator 203; cooling intercooler 206 for low-pressure compressed air from the low-pressure stage compressor body 204 and supplied to the high-pressure stage compressor body 205; cooling An aftercooler 207 of high-pressure compressed air discharged from the high-pressure stage compressor body 205 ; and an oil supply device 208 supplying lubrication of bearings of the compressor bodies 205 , 206 and gears of the accelerator 203 and the like. In addition, a control board including a microcomputer is installed on the noise insulation cover 209, and the operation of the compressor 200 is controlled through the control board.

Although the screw compressor constitutes a box-like structure as described above, which has the advantages of improved appearance and reduced noise, there arises a problem that inspection of internal parts is inconvenient and requires a large maintenance work space.

On the other hand, users wish to reduce labor costs by making maintenance work more convenient.

The dry screw compressor is designed in such a way that the convex rotor and the concave rotor are meshed in a non-contact manner, and a small gap is maintained through the synchronous gear to compress the air in the compression chamber in the compressor shell. Therefore, this dry screw compressor has a small gap between the two rotors and between the rotor and the casing, and there is no oil in its compression chamber. If the compressor is not working, the surface of the rotor is rusted due to the condensation of water vapor in the air, and the rust spots cause the tooth surfaces of the convex and concave rotors to stick to each other, or the rotor and the wall of the compression chamber to stick to each other. The result is a phenomenon in which the rotor is blocked, preventing the rotor from turning.

So far, as a method of improving the anti-corrosion performance of the rotor surface, solid lubricating materials are firmly added to the rotor surface to form a coating, such as molybdenum disulfide (hereinafter referred to as "MoS ₂ ") or granular powder such as tetrafluoroethylene ( hereinafter referred to as "PTFE") and the like.

For example, MoS ₂ thin films have hitherto been fabricated by the process shown in FIG. 19 . That is, firstly, the screw rotor is processed into a shape with a predetermined size, then, the process 118 cleans and degreases the tooth surface of the rotor, and the process 120 is manganese phosphate treatment (dipping). Then there is a screw rotor drying process 122, a coating process 124 of a paint mainly composed of MoS ₂ , and then baking processes 126 and 127. If necessary, the steps 124 to 128 shown in Fig. 19 are repeated to obtain the desired film thickness and improve the corrosion resistance of the rotor. As a result, clogging of the rotor due to corrosion is avoided.

However, due to the heat resistance of the binder used in the MoS ₂ coating - the heat resistance of the manganese phosphate film is about 200°C, when the compressor works for a long time and the compressor discharge temperature exceeds 200°C, the resistance is reduced. The ability to corrode and thus cause the rotor to rust due to moisture in the air, thereby causing the rotor to be braked.

Therefore, preventive measures must be taken, such as adding an operating system, which includes a "long-term non-operation" switch installed on the compressor control board, and is designed to enter the operation when the switch is turned on, and shut down under no load The intake valve, the screw compressor takes about 20 minutes to remove the moisture in the compression chamber through evaporation, and then automatically stops working.

A rotor with a coating of _MoS2 particles bonded together with an epoxy resin binder was also proposed (Japanese Patent Laid-Open (Unexamined Publication) No. 2-201072).

As this type of technology for making the coating film on the rotor base surface, a rotor is disclosed. The matrix of this rotor is a synthetic resin, the surface layer is an ethylene-tetrafluoroethylene copolymer, and it is directly or indirectly reinforced with carbon fibers (see Japan Patent Laid-Open No.2-75789 and No.1-301977). In addition, a rotor is disclosed which consists of a base body of the rotor, an anti-corrosion coating on the base body and a solid lubricant surface layer (see Japanese Patent Laid-Open No. 2-301694). Also provided is another kind of rotor, and it is made up of ductile iron, electroless nickel plating layer, polyphenylene sulfide resin layer and organic resin such as epoxy resin surface layer (seeing Japanese patent Laid-Open No.3-290086). In addition, a rotor has been proposed, which is based on aluminum alloy or magnesium alloy, etc., and a thermosetting resin layer is added on this basis (Japanese Patent Laid-Open No. 3-271586).

For example, Japanese Patent Laid-Open No. 61-190184 proposes the thickness of the coating on the screw rotor substrate.

The purpose of the present invention is to facilitate the daily inspection and maintenance work required for the box-type complete set of screw compressors, and to reduce the space required for maintenance and equipment installation.

Another object of the present invention is to prevent the discharge air from flowing into the passage through which the cooling air of the motor flows when the compressor is running at no load.

Yet another object of the invention is to prevent rust formation on the screw rotor and thus prevent the rotor from being braked in the gas compression chamber due to rust formation.

In order to achieve the above-mentioned objects, the present invention provides that those parts of the compressor which are subject to daily inspection are mounted near the front panel and at a side panel adjacent to the front panel.

According to a technical solution of the present invention, a box-type complete screw compressor is provided, which includes:

Parts having: at least one compressor body; at least one gas cooler for cooling gas discharged from the compressor body; a coolant cooler for cooling a coolant used to cool the compressor body's shell; a an air inlet pipe for introducing uncompressed gas into the air inlet of the compressor body; and a control panel for regulating and displaying the operating conditions of the compressor body; and

A box comprising a box-like frame and a plurality of panels, each panel having a front panel covering at least a portion of the front of the frame and side panels covering at least a portion of the sides adjacent to the front, the box containing substantially the above-mentioned components;

It is characterized in that: the compressor includes one of the front panel and the side panel, and the control panel is installed on the front panel; There is an oil level gauge to display the level of lubricating oil in the oil tank. The oil tank stores lubricating oil, which is used to lubricate the bearing of the compressor body; the lubricating oil is supplied to the oil supply port of the oil tank; a filter for lubricating oil supplied to the bearings of the compressor body; an oil cooler for cooling said lubricating oil; and a condensate check valve mounted on a branch pipe from a condensate drain pipe for draining Condensed water separated from compressed gas cooled by a gas cooler.

The front panel consists of two door panels, one of which may have a maintenance time screen or display on its fabric, indicating the time at which maintenance work should be performed. The door panels are openable about their mutually remote or opposite side ends. The two panels can be joined together on a central frame between the two panels, which can be removed when the panels are opened.

The intercooler (more specifically the compressor body intercooler) and the aftercooler (more specifically the compressor body aftercooler) are suitably fitted with tube bundles which can be inserted into or removed from the shell Take it out. The intercooler and aftercooler can be installed in the same direction as the tube bundle was removed. The tube bundle can be withdrawn towards the front or rear plate.

Movable casters are fitted under the gas coolers (intercooler and aftercooler) to allow them to move on rails housed in the box.

The end caps of the gas cooler, ie the intercooler and the aftercooler, are designed to pivot about hinges on the housing.

The installation direction of the coolant cooler and the lubricating oil cooler, that is, the removal direction of the coolant cooler and the lubricating oil cooler, can be the same as that of the intercooler and aftercooler tube bundles.

The intake duct can be designed so that it slides in a direction towards one of the side panels when it is removed. A slidable beam may be mounted to extend in the direction of one of the side panels.

The compressor intake pipe and air inlet can be connected by a rubber elbow for easy disassembly.

The mounting support supporting the maintenance crane column can be made in the box. The mounting support can be located at any one of the four corners of the box on the base. A rod crane, or a part thereof, may be pre-mounted on one or more mounting brackets.

The air discharge pipe used for the exhaust of the compressor body when it is running without load can be installed in the discharge pipe of the motor cooling air, so that the motor cooling air flows around the air discharge pipe, so the exhaust and motor cooling air are discharged into the atmosphere separately.

The preferred embodiment of the present invention stipulates that the bodies of low-pressure and high-pressure screw compressors and the main motor are respectively cantilevered on the accelerator casing, and the shaft of the compressor body and the motor shaft are connected through the speed-up gear. The axis of the screw or motor extends parallel to the front plate. The intercooler is installed in the space below the compressor body, and the aftercooler is installed above the accelerator. The lubricating oil cooler and the coolant cooler are installed under the motor. The longitudinal direction of each cooler is perpendicular to the axis of the motor or compressor body. The intake pipe is installed above the compressor body between the aftercooler and a side panel, and the control panel is installed on a part of the front door panel opposite to the main motor. In addition, the condensed water discharge port of the gas (air) cooler is provided on one side of the side plate.

Front panel and one side panel adjacent to the front panel, selected or designed as those sides from which daily inspections are to be carried out, where the oil level dipstick, lubricating oil supply port, lubricating oil filter and condensate check valve And preferably there is also a motor grease port, which is installed on the side near the daily inspection. As a result, the personnel who carry out the daily inspection can complete the inspection work in the vicinity of the above-mentioned side where the daily inspection is carried out. Therefore, inspection work can be easily performed, and the time required to complete the work can be shortened.

Since the parts to be inspected daily are concentrated on two sides, a space for inspection work is required in front of the above two sides. Therefore, even if the installation space is limited or even if the installation direction is limited, maintenance work can be easily performed.

In the case where the front panel is composed of two door panels (front panel parts) and can be rotated around the side ends away from or opposed to each other to open, the front panel part can be opened. Therefore, maintenance and inspection work can be easily performed. When the center plate can be removed, inspection work can be facilitated, and the work of dismantling or taking out the internal components can be easily performed.

Since the tube bundle of the air cooler is drawn out in the longitudinal direction of the cooler, a space corresponding to the length of the tube bundle is required in the longitudinal direction of the cooler to completely dismantle the tube bundle. When the intercooler and aftercooler are removed in this same direction, the total maintenance space can be reduced because the tube bundle moving space can be concentrated only in front of one plate. If the pipes are moved into the space in front of the front panel, the inspection space and the maintenance and repair space can be shared. Therefore, the space required for installing the compressor can be reduced. If necessary, the inspection space in front of the front panel can be reduced by means of the installation space, the space opposite it or in front of the rear panel part can be used as maintenance space, and the cooler tube bundle can be moved in the direction of the rear panel.

When the casters are installed under the gas cooler and the whole gas cooler can be taken out along the longitudinal direction of the cooler, the gas cooler can be maintained while avoiding cooling water to pollute the inside of the box.

Also doubles as air cooler end cap for condensate separator; is opened when removing tubes or inspecting cooler tubes. While the end cap can be opened/closed about the hinges that secure the cover to the outer cover, the end cap can be opened or closed by removing the screws and piping that secure the cover to the housing. Therefore, there is no need to lift the cover separately with a crane, obviously, maintenance and inspection work of the cooler can be easily performed.

Space required for disassembly and maintenance of the coolant cooler and lubricating oil cooler when the coolant cooler and lubricating oil cooler are also mounted so that their longitudinal direction is the same as the direction in which the tube bundles of the intercooler and aftercooler move when they are removed , which can be shared with the space required for servicing the air cooler. Therefore, the space required for installing the compressor can be reduced.

Since the intake pipe in the box is installed above the compressor body, it should be disassembled when performing maintenance and inspection work. When the intake duct is formed in a separate box shape and installed so as to slide toward the side panel portion within the noise insulating cover, the intake duct can be easily disassembled without lifting it from the upper position. Therefore, maintenance work is easy to carry out.

The air intake pipe and air inlet of the compressor are connected to each other through rubber elbows, which makes assembly and disassembly work easy.

While inspection and maintenance work requires equipment such as cranes to move or remove some components, equipment such as cranes and "I" beams are sometimes not located where the compressor will be used. However, if the installation support for supporting the column is prefabricated in the compressor casing to fix the maintenance crane, it is no longer necessary to install the crane in addition. A mobile crane that can be broken down is sufficient to perform repair work satisfactorily. Thus, the outlay in building workshops or structures is reduced. If the compressor is suitable for use with a pole crane having a column mounted on one of the mounting brackets, the components inside the box can be removed for maintenance work by simply removing a part of the noise insulating cover. The above-mentioned maintenance work is, for example, repairing the accessories of the compressor body. Therefore, the time required to complete the maintenance work is shortened.

There is no need to worry about hot exhaust air flowing to the motor when the air discharged from the compressor running at no load is discharged separately from the air that cools the motor. Adopting the structure that the cooling air of the motor flows around the exhaust pipe, it can cool the hot exhaust pipe, and can avoid the noise generated when passing through the side of the exhaust pipe when the state between no-load operation and load operation is switched on. The air discharge port after cooling the motor surrounds the structure of the discharge port of the compressor body, which can reduce the temperature of the hot air discharged from the discharge port of the compressor body.

In the case that the main motor and the compressor body are respectively fixed on the accelerator casing in a cantilever manner, the maximum (longitudinal) length in the box is the total length of the main parts composed of the main motor, accelerator and compressor body. Therefore, this main part preferably extends parallel to the front plate, and an intercooler, which doubles as a connecting pipe between the low-pressure stage compressor and the high-pressure stage compressor, is housed in the space below the compressor body. At this time, as long as the height of the main part is properly designed, the tube bundle of the intercooler can be taken out without being blocked by the frame (such as the frame at the bottom of the noise insulation cover). The coolant cooler and lubricating oil cooler are preferably installed in the space below the main motor, while the aftercooler is installed above the accelerator. Since the exhaust port of the high-pressure stage compressor opens upwards, the aftercooler also acts as a part of the exhaust pipe. Therefore, the exhaust port of the box body can be made on the top of the side plate, reducing the length of the exhaust pipe in the box body. It is better to install the intake pipe in the upper space of the compressor body, so as to maintain the layout of the aftercooler above the accelerator. In addition, the control board is preferably mounted on one of the front panel doors, adjacent to the motor, so that the temperature of the motor and thus this door panel is relatively low. In the case where the condensed water discharge port of the air cooler is formed, for example, at the lower end or upper end of one side or part of a side plate, the pipes of the water supply system and the air supply system may be concentrated on one side plate portion. Cooling water pipes and air pipes are connected to this side plate. Therefore, the layout in the cabinet is easy to design. If these components are arranged as described above, the space inside the box can be effectively used, and thus the size of the box can be reduced.

In order to achieve the above still another object, the present invention provides that a primer layer is applied to each lobe of a screw rotor which has been machined to have a predetermined tooth shape, followed by drying and baking. Then, a paint composed of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter referred to as "PFA") is uniformly deposited or coated, followed by drying and baking to form PFA on the surface of the rotor lobe. Film or coating, thus avoiding the rotor from rusting.

It is best to form a PFA coating film through the following procedures: apply a low-level coating solution mixed and diffused by PFA particles, binders, pigments and water on the surface of the rotor substrate, followed by drying and baking; coating PFA particles, bonding The PFA coating solution prepared by dispersing the agent and pigment in water is then dried and baked to a temperature where the PFA particles melt on the rotor substrate to form a continuous coating film.

If the PFA coating is added to cover the rotor base with a uniform film, the melted PFA particles in the film form a continuous layer, which will not easily form pores. Therefore, even if the thickness of the PFA film is small (50 microns or less), a significant antirust effect can be achieved. Since the molten PFA particles solidify to form a uniform overall layer, there is no need to worry about damaging the coating layer due to falling granular powder.

Due to the non-adhesive nature of PFA, impurities, such as dust in the air, that intrude into the small gap between the male and female rotors or between the rotor and the housing can be easily discharged. Thus, the problem of rotor clogging due to accumulated impurities is avoided.

As mentioned above, the PFA coating on the dry screw compressor rotor can minimize the rusting of the rotor. Thus, clogging due to rust in the small gap between the rotors or between the rotor and the housing can be avoided. As a result, rotor braking due to rust is avoided.

Other and further objects, features and advantages of the present invention will be fully understood from the following description.

Fig. 1 represents the perspective view of the inner part arrangement of the box-type complete set of screw compressors according to an embodiment of the present invention;

Figure 2A shows a plan view of the arrangement of internal components of the compressor shown in Figure 1;

The back view of the structure shown in Fig. 2B Fig. 2A;

Figure 3 shows a block diagram of the working relationship of the components of the compressor shown in Figure 1;

Fig. 4 shows the front view of the appearance of the compressor casing shown in Fig. 1;

Figure 4A shows an explanatory view of the structure supporting the air cooler on casters;

Figure 4B shows an annotative view of an example of a detachable central frame structure fixed on the outer frame;

Fig. 5 shows a plan view of the opening/closing of the door panel of the compressor shown in Fig. 1;

Fig. 6 shows a plan view of the part of the compressor shown in Fig. 1 to be subjected to routine inspection;

Fig. 7 shows a side view of the direction in which the tube bundle of the compressor air cooler shown in Fig. 1 is taken out;

Fig. 8 shows a side view of the intercooler of the compressor shown in Fig. 1 slidably drawn out;

Fig. 9 shows a plan view of the condition that the air cooler end cover of the compressor shown in Fig. 1 is opened/closed;

Fig. 10 shows the assembled situation of the crane for overhauling the compressor shown in Fig. 1;

Fig. 11 represents the perspective view of the compressor intake pipe shown in Fig. 1 taking out the way;

12A and 12B are respectively a cut-away end view and a partially broken rear view of the combined structure of the compressor exhaust pipe and the motor exhaust pipe shown in FIG. 1;

Figure 13 represents an illustrative diagram of various pressure reference levels;

13A to 13D are process flow charts for adjusting compressor production capacity and setting and controlling the pressure level for automatic activation when pipeline pressure drops;

Figure 14 shows an annotative view of the switches and displays mounted on the control board for carrying out the controls shown in Figures 13A to 13D;

Fig. 15 shows the perspective view of the arrangement of internal components in a conventional box-type packaged screw compressor;

Figure 16 shows a perspective view of the engagement between the male rotor and the female rotor of the screw compressor;

Figure 17 represents the enlarged view of the coating according to an embodiment of the present invention, showing the essential part of the relationship between the screw rotor base body and the coating in an enlarged and cross-sectional manner;

Fig. 18 carries out the technological process of PFA coating according to the embodiment of the present invention;

Figure 19 is the process flow of conventional _MoS2 coating;

Fig. 20 The effect of the screw compressor with PFA coating on the screw rotor lobes to prevent the rotor from clogging due to rust is compared with the effect obtained by the screw compressor with MoS ₂ coating on the screw rotor lobes Comparative graphs simulating the phenomenon of clogging in tests carried out to assess clogging;

Figure 21 represents the process of forming the PFA coating layer;

Figure 22 represents the process of forming a conventional PTFE coating layer; and

Figure 23 shows the process of forming a conventional _MoS2 coating layer.

Referring to Figs. 1, 2A, 2B and 3, a box-type screw compressor according to a preferred embodiment of the present invention will be outlined.

The accelerator 3 is installed on the base 21 of the complete set of compressors, and a vibration-isolating rubber 3a is inserted between them. The low-pressure compressor (body) 1 and the high-pressure compressor (body) 2 are fixed on the accelerator 3 in a cantilevered manner. The main motor 4 is a flange type motor, which is fixed on the accelerator 3 through the flange portion of its housing. The upper parts 1 - 4 are arranged such that the centerline A of their rotation axis coincides with the longitudinal direction X of the base 21 . In the lower space of the low-pressure stage compressor 1 and the high-pressure stage compressor 2, there is an intercooler 5 (more specifically, a compressor (body) intercooler), which cools the low-pressure compressor discharged from the low-pressure stage compressor 1. Compresses the air and acts as a connecting pipe connecting the two compressors 1 and 2. There are casters 25 that can roll on the track 26 at the support portion of the intercooler 5, and the track 26 is mounted on the base 21. Therefore, the intercooler 5 can be taken out by sliding or moved along the Y direction when doing maintenance work. The intercooler 5 is usually fixed on the base 21 by brackets 27 and vibration-isolating rubber 27a, which make the casters 25 and the rails 26 in a non-contact state (the state shown by the solid line in FIG. 4A ). If the nut 27b is loosened, the intercooler 5 can move down, and the bracket 27 also moves down to the position shown by the dashed line in FIG. 4A , so that the caster 25 can be placed on the track 26 . The aftercooler 6 (more specifically, the compressor (main body) aftercooler) for cooling the high-pressure compressed air discharged from the high-pressure stage compressor 2 is fixed above the accelerator 3 by vibration-isolating rubber. As will be described later with the help of Fig. 9, the intercooler 5 and the aftercooler 6 are shell-and-tube condensers, and they are designed as an integral tube bundle structure 35c installed in the shell 35, and the tube bundle structure 35c consists of a partition Plate 35a and cooling pipe 35b. The tube plate (end plate) 33 mounted on one side is a plate movable within a certain range, thus forming a structure that allows the tube bundle 35c to be drawn out or moved in the Y direction during cleaning. Since two coolers 5 and 6 are provided, both the tube bundle 35c of the intercooler 5 and the tube bundle 35c of the aftercooler 6 are moved or drawn out in the same direction Y. A lubricating oil cooler 7 for cooling lubricating oil is installed under the main motor 4, and the lubricating oil is used to lubricate the bearings of the compressors 1 and 2 and the gears of the accelerator 3; the coolant cooler 8 is used to cool the coolant, and the coolant is used for cooling The antifreeze of the shells 1a and 2a of the compressor bodies 1 and 2 is composed. The lubricating oil cooler 7 and the coolant cooler 8 are installed such that their longitudinal directions are perpendicular to the direction X of the output shaft of the main motor 4 . The oil pump 9 for supplying lubricating oil is located above the lubricating oil cooler 7 and the coolant cooler 8, so the removal or movement of the lubricating oil cooler 7 and the coolant cooler is not affected. The lubricating oil filter 13 provided in the lubricating oil flow path cooled by the lubricating oil cooler 7 is adjacent to the low-pressure stage compressor 2 . The coolant cooler 10 is installed below the aftercooler 6 and on one side of the accelerator 3 .

All the aforementioned parts are covered with a box-shaped noise insulation cover 22 . The noise insulation cover 22 is fixed on a plurality of outer frames 51 , and the outer frames 51 are directly or indirectly fixed on the base 21 , and they constitute the frame of the box 50 . The cover 22 is also connected to the starter control panel 12 which is mounted on the base 21 and forms part of the front of the box 50 . One or more (detachable) front plates 52, rear plates 53, side plates 54 and top 30 and a motor suction pipe 24 are all fixed on the noise insulation cover 22. Although the noise insulating cover 22 is of the plate type, it differs from the plates 52 , 53 and 54 in that the noise insulating plate 22 is not detachable with respect to the frame 51 . The control panel 11 is connected to one of the detachable panels 52a, 52b constituting the front panel 52, so the control panel 11 is fixed to the door panel 52a. The door panels 52a, 52b, 53a, and 53b constituting the front panel 52 and the rear panel 53 are hingedly mounted at side ends that are far apart from each other. The front plate 52 and the rear plate 53 are opposed to each other.

The intake pipe 18 that air is sucked into the low-pressure stage compressor (body) 1 is contained between the aftercooler 6 and the side plate 54, above the compressor body 1 and 2, and will be described in detail below by means of Fig. 11 . The air intake pipe 18 is installed on a part of the frame of the noise insulation cover 22, and is installed so that the air intake pipe 18 can slide along the X direction so as to be pulled out through the side plate 54. The intake filter 19 is installed in the intake pipe 18, and the intake filter 19 is connected with the suction port 16 of the low-pressure stage compressor 1 through a rubber elbow 20. The exhaust pipe 15 of motor is contained in the top of an exhaust port, and this exhaust port is used for releasing the air that is cooled by built-in fan (not shown) for cooling main motor 4. The exhaust pipe 15 is fixed on the partial frame 51 of the noise insulation cover 22. There is an upper surface of the exhaust pipe 15 covered by the top plate 30 having the exhaust holes 46. See FIGS. 12A and 12B, which will be described in detail below. An exhaust cavity or pipe 16 is contained in the motor exhaust pipe 15, and an exhaust muffler 17 is built in, and the muffler is used to exhaust air from the compressors 1 and 2 when the compressor bodies 1 and 2 are running without load, so, from The air discharged by the motor 4 and the exhaust air from the compressor are all discharged outside the case, but they are not connected with each other.

Formed on the base 21 upper surface is the bearing 28 that the crane of maintenance work uses. The support 28 located at the intersection of one end of the front plate 52 and one end of the side plate 54 is also used as a support for the fixed rod crane 36 for inspection and maintenance work, which will be described in detail later with the help of FIG. 10 .

The air that enters from the suction port of the top plate 30 passes through the intake pipe 18, the intake filter 19 and the rubber elbow 20, and then, before the air is sucked into the low-pressure stage compressor 1, flows through a flow regulating valve not shown in the figure . The air compressed by the low-pressure stage compressor 1 is cooled in the intercooler 5 and compressed by the high-pressure stage compressor to a prescribed pressure level. Then, the compressed air is discharged from the exhaust pipe 6a after being cooled by the aftercooler 6 . When the compressors 1 and 2 are running without load, the air discharged by the compressors 1 and 2 flows through the exhaust muffler 17, enters the exhaust pipe 16, and then is discharged out of the box through the vent hole 45 of the top plate 30 (see Figure 12A). . Condensed water generated in the air coolers 5 and 6 is discharged through the drain port 14 of the drain pipe 14 a provided in the base 21 below the side plate 54 . The branch pipe 14b is connected to the drain pipe 14a, and the branch pipe is provided with a condensed water check valve 14c to check whether there is condensed water flowing through the drain pipe 14a.

As shown in FIG. 3 , the main motor 4 drives the low-pressure compressor 1 and the high-pressure compressor 2 through the accelerator 3 . A fan (not shown) is housed in the main motor 4, and it sucks cooling air from the outside of the complete set of equipment, that is, the casing of the label 50, through the motor intake pipe (not shown). The hot air after cooling the motor 4 is discharged outside the box 50 from the vent hole 46 (see FIG. 12A ) of the top plate 30 through the motor exhaust pipe 15 . All are provided with sound-absorbing device 47 (seeing Fig. 12A and 12B) on the inner surface of motor intake pipe and motor exhaust pipe 15, so the leakage of noise from box 50 can be reduced to the minimum.

The lower part of the accelerator 3 is an oil tank 3b. The lubricating oil sucked out by the oil pump 9 from the oil tank 3b is cooled by the lubricating oil cooler 7 before being supplied to parts such as bearings of the compressor bodies 1 and 2 and gears of the accelerator 3 through the oil filter 13 . The lubricating oil filter 13 of the aforementioned parts in the lubricating system should be checked every day. It is installed adjacent to the side plate, and the maintenance and inspection frequency of the lubricating oil cooler 7 is slightly lower, so the platform installed on the base 21 on the rack 21a so as to be pulled out or moved individually slidingly on the stand 21a.

The coolant cooling the shells 1 a and 2 a of the compressor bodies 1 and 2 is circulated by means of a coolant pump 10 , and it is cooled by cooling water in a coolant cooler 8 .

The cooling water supplied from the outside of the box 50 is supplied to the intercooler 5, the aftercooler 6, the lubricating oil cooler 7 and the coolant cooler 8 respectively through the main water supply pipe 29 installed on the base 21. The cooling water after absorbing heat in each of the coolers 5 to 8 is collected in the main drain pipe 29 a and then discharged out of the tank 50 . The lubricating oil cooler 8 can be cooled by the coolant cooled by the coolant device 7 . In this case, cleaning of the lubricating oil cooler 8 can be almost dispensed with, thereby reducing maintenance costs.

When constituting this box-type screw compressor (assembly or equipment) 55 as described above, the space in the complete set or box 50 can be fully utilized to reduce the size of the box 50, so the volume required for placement is reduced to lowest. In addition, inspection and maintenance work has been improved.

As can be seen from Figures 4 and 5, the front panel and the rear panel are made up of double door panels 52 (52a and 52b) and 53 (53a and 53b) respectively, and two door panels 52a and 52b (53a and 53b), as shown in dotted lines in Figure 5 , be mounted on the frame 51 of the noise insulation cover 22 with hinges, and the hinges are respectively at the side ends away from each other. When the door panels 52a, 52b, 53a, 53b are closed, they are fixed to the central frame 31 which is configured similarly to the outer frame 51 . As shown, for example, in FIG. 4B, the central frame 31 is formed as a "U"-shaped upright having one end wall 31a. The end wall 31a is detachably fixed on the adjacent outer frame 51 (the bottom outer frame in the illustrated case) by screws 31b. When the door panels 52 and 53 are opened, the center frame 31 can be easily removed. Therefore, it provides convenience for inspection and maintenance work.

The control panel 11 is fixed on the front side of one (52a) of the door panels 52a and 52b. The outer surface of the control board 11 becomes a part of the outer surface of the case 50 . The fact that the components are basically housed in the case 50 shows that the control board 11 and the like function as part of the case 50 . The control board 11 has the following functions, for example, the function of starting and stopping the compressor and equipment; the function of digital display or representation of temperature, pressure, current, running time, number of starts and no-load work times; display or indication of fatal failure and Fatal failure functions; and, protection functions such as emergency stop. In addition, the control panel 11 also has the operation adjustment function, for example, by automatically determining the flow rate to adjust the pressure to achieve energy-saving operation; automatic stop when the no-load continuous working time is too long; automatic stop when the pipeline pressure is too low; and, run according to the program . In addition, it also has the following preventive and safety functions: After analyzing and comparing the cooling water temperature used for cooling equipment (such as air coolers 5 and 6 and lubricating oil cooler 7) with the temperature of the cooled liquid, display or indicate The function of whether the cooler needs to be cleaned; the function of displaying or indicating the pollution situation and cleaning according to the pressure loss and pressure level in the air filter 19 and the lubricating oil filter 13; and, displaying or indicating the moment when the motor 4 should be supplied with grease function. Moreover, it also has the following functions: displaying the time when the auxiliary equipment of the compressor body 1 and 2 should be inspected, the time when the body 1 and 2 should be inspected, and displaying the time when the inspection should be performed. The control of the inspection time is based on the working hours of the compressor bodies 1 and 2 and the elapsed time after the equipment is installed. This function is provided to display or indicate that the time for inspection has arrived when a specified number of hours has been worked or a specified number of years have elapsed since the equipment was installed. If it is automatically stopped due to a failure, the operating parameters, such as the instantaneous temperature of each part immediately before the automatic stop, are stored, so even if the compressors 1 and 2 have stopped working, they can be displayed or indicated on the control panel. Instantaneous running parameters before automatic stop. Some of the above-mentioned control functions of the control board 11 are disclosed in EP-A1-0482592 and EP-A1-0460578.

The pressure value set for adjusting the flow rate can be arbitrarily selected in the control panel 11. The design scheme stipulates that the set pressure cannot be higher than a certain pressure value, so as to avoid the pressure exceeding the upper limit of the allowable pressure of the compressor. If one of the specified values is changed, the upper limit pressure level shall be prevented from falling below the lower limit value. When the pressure difference between them decreases below a certain value, the other set value is automatically changed to maintain the minimum allowable pressure difference. If the set value is automatically changed, this change is displayed by the flash.

An example of adjusting the production capacity of the compressor (equipment) 55 and adjusting the prescribed pressure value for automatic start-up when the pipeline pressure drops is explained with reference to FIGS. 13 , 13A to 13D and 14 .

As shown in Figure 13, assuming that the limit pressure of the compressor is P _max , the upper limit of the discharge pressure is P _U , the lower limit of the discharge pressure is _PL , the automatic start pressure of the compressor is P _A , and the minimum level of the automatic start pressure is P _Amin , And the rated or working pressure is P.

Compressor 55 works automatically according to the following steps (i) to (iv):

(i) When the discharge pressure P is increased to _PU , the compressors 1 and 2 are operated under no load (no-load operation).

(ii) When the discharge pressure P is low to _PL , the compressors 1 and 2 are operated under load to discharge air (operating under load).

(iii) Repeat steps (i) and (ii) above.

(iv) When the compressors 1 and 2 stop, if the pressure in the pipeline is lower than P _A , the compressors 1 and 2 will start automatically.

Perform the above adjustments under the following conditions:

(a) Used to regulate the operation of compressors 1 and 2 with and without load.

(b) The following relationships must be maintained: P _U > P _L > P _A and P _max ≥ P _U .

This is because, if _PU and _PL are reversed ( _PL ≥ _PU ), the compressors 1 and 2 cannot be controlled. If P _A >P _L , an undesired automatic start signal is always issued during operation of the compressors 1 and 2, causing malfunctions of various components.

(c) If △P=P _U -P _L is too small, a short-term repeated oscillation phenomenon occurs between load and no-load operation, resulting in damage to the production capacity control part. Therefore, ΔP _1min should be determined while maintaining the relationship ΔP ₁ ≥ ΔP _1min .

(d) As for △P=P _{L -PA} , when determining △P _2min , the detection error and pressure change of the pressure detection equipment (not shown in the figure) should be considered, and the relational formula △P≥P _2min should be maintained.

The above-mentioned adjustment and control are carried out according to the process flow charts in Figs. 13A to 13D.

First, at step 60, the operating mode changeover switch 59a of some related switches on the control panel 11 shown in FIG. 14 is pressed down, thereby selecting the pressure regulation mode.

Then, press the pressure selection switch 59j to select the state of adjusting the upper limit of the discharge pressure, then, the flow chart moves to step 61, at this time, the current upper limit value _PU is displayed on the digital display or screen 59b. In the next step 62, the light emitting diode (LED) 59c turns on, indicating that the upper limit of the exhaust pressure has been reached. If the selected upper limit P _U is raised, depressing the selected value increment switch 59d moves the flow chart from step 63 to step 64. When the upper limit value P _U < P _max , the value of P _U is increased in step 65, and the value displayed on the screen 59b is also changed. If P _U <P _max , repeat steps 63 to 65 and increase the upper limit P _U . On the other hand, it is not allowed to select _PU to maintain the relationship _PU ≥ P _max , since this would make the above condition (b) not satisfied. Therefore, the process loops back. At this moment, an alarm signal is issued.

If the selected upper limit _PU is lowered, the selected value down switch 59e is depressed, so the flow moves from step 66 to step 67. In step 67, the _PU value is decreased and the value displayed on the screen 59b is also changed. In a next step 68, ΔP ₁ =P _U -P _L is compared with ΔP _1min . If ΔP ₁ ≥ ΔP _1max , repeat steps 66 and 67, and decrease the upper limit P _U . On the other hand, if it is determined in step 68 that ΔP ₁ ≥ ΔP _1max , then in step 69 the lower limit value _PL is changed so as to maintain the relationship ΔP ₁ ≥ ΔP _1max . In step 70, the character LED 59f "LOWER LIMIT OF DISCHARGEPRESSURE" is turned on and off (blinking) to notify the change of the lower limit value _PL . In step 71, ΔP ₂ =P _{L -PA} is compared with ΔP _2min when _PL has changed as described above. If ΔP ₂ ≥ P _2min , steps 66 to 71 are repeated, so that the upper limit _PU and the lower limit _PL are decreased. If it is judged that △P ₂ <△P _2min , change the automatic starting pressure _PA in step 72 to maintain the relational expression △P ₂ =△P _2min , in step 73, the character LED59g "automatic starting pressure"("AUTOMATIC STARTING PRESSURE") is turned on and off (flashing) to notify the change of the automatic starting pressure _PA . If the upper limit value _PA is further lowered, steps 67 to 73 are repeated.

If it is confirmed that the upper limit _PU can be made into a predetermined value by increasing or lowering the upper limit _PU , then the adjustment main switch 59h is pressed, so that the process skips step 63 or 66, through step 74 to step 75, in step 75, The character display 59c "upper limit of exhaust pressure"("Up-PER LIMIT OF DISCHARGEPRESSURE") stops blinking. In step 76, the values _PU , _PL and _PA determined in the preceding steps are adopted as currently selected values, and in step 77 the pressure regulation state is terminated.

When the mode switch 59a is pressed to select the pressure changing mode, and the pressure selection switch 59j is pressed to select the lower limit _PL of the discharge pressure, the flow goes to step 78, at which time the current value of the lower _PL is displayed on the screen 59b. In the next step 79, the LED 59f indicating the lower limit of the discharge pressure is turned on.

If the lower limit value _PL is increased, the increase switch 59d is pressed, and the flow moves from step 80 to step 81 . A comparison is made between ΔP ₁ =P _U -P _L and ΔP _1min . If ΔP ₁ >ΔP _min , increase the value _{of PL} in step 82, and repeat steps 80 to 82, so the lower limit value _PL increases. If it is judged that ΔP ₁ ≤ ΔP _min , condition (c) is not satisfied. Therefore, incrementing _PL is not allowed and the process returns. An alarm signal is issued at this moment.

If the lower limit value _PL is to be decreased, depressing the decrease switch 59e moves the flow from step 83 to step 84 where the value of _PL is decreased. In steps 85 to 87, similarly to steps 71 to 73, _PL is lowered to a predetermined value and, if necessary, the value of _PA is also lowered.

If it is judged in steps 80 to 87 that the drop value _PL can be increased or decreased to a predetermined value, then similar to the previous situation, the adjustment master switch 59h is pressed, and the flow process moves to steps 74 to 76 from step 80 or step 83, So the determined values _PL and _PA apply as currently selected values. The pressure regulation mode then ends in step 77 .

Similarly, when the pressure adjustment mode is selected using the mode switch 59a, and the mode for adjusting the auto-actuating pressure _PA is selected using the pressure selection switch 59j, the flow goes to step 88 where the current value of the auto-actuating pressure _PA is determined by displayed on the screen 59b. In the next step 89, the LED 59h indicating the autostart pressure is turned on.

When increasing the autostart pressure _PA , depress the increment switch 59d, so that the flow from step 90 to step 91. In step 91, ΔP ₂ =P _{L -PA} is compared with ΔP _2min . If ΔP ₂ ≤ P _2min , increase _PA in step 92, and repeat steps 90 to 92, so the autostart pressure _PA rises. If it is judged in step 91 that ΔP ₂ ≤ P _2min , condition (d) is not satisfied. Therefore, incrementing _PA is not allowed and the process returns. At this moment, the alarm signal is turned on.

When lowering the autostart pressure _PA , depressing the decrement switch 59e makes the flow go from step 93 to step 94. If the pressure is higher than the minimum autostart pressure P _Amin , in a repetition of steps 93 to 95 , in step 95 _PA is reduced again.

When P _A reaches the predetermined value, the main switch 59h is depressed, so that the automatic starting pressure P _A is selected as the current value in steps 74 to 77 .

The pressure adjustment system shown in Figures 13, 13A to 13D and 14 ensures that problems due to misadjustment are avoided and misadjustment is essentially avoided.

The above-mentioned adjustment is accomplished by the regulator 97 shown in Fig. 3, which includes a microprocessor which contains a program according to the flow shown in Figs. 13A to 13D.

Fig. 6 is a plan view showing the parts of the complete plant that are subject to daily maintenance or routine inspection. Near the front panel 52 where the control panel 11 is housed, there is a hole 56 for adding grease, a lubricating oil level gauge 57 and a lubricating oil supply port 58 to be checked. In addition, adjacent to the adjacent side plate 54 are lubricating oil filter 13 and air cooler condensed water discharge port 14 . Front panels 52 and side panels 54 are added to the sides or directions D and E where routine inspection is performed. Therefore, the operator does not need to move around the compressor 55 for daily inspection. In addition, the space required to install the tank 50 is reduced and/or the space required to accommodate the compressor device 55 and the maintenance space can be reduced.

FIG. 7 shows the direction Y1 of moving or withdrawing the tube bundle of the intercooler 5 and the tube bundle of the aftercooler 6 . After the front panel 52 is opened, the intercooler 5 and the aftercooler 6 can be moved in the direction Y1 through the opened front panel 52 .

FIG. 8 is a side view showing how the intercooler 5 is slidably drawn out. For example, after opening the front panel 52 and the side panel 54, the high pressure stage suction pipe 32 is removed. The nut 27b in Fig. 4A is loosened, and the bracket 27, which was fixed before this, moves down. When the casters 25 are placed on the rails 26, the intercooler can be moved in the direction Y1. Since the whole intercooler 5 can be easily taken out of the box 50, the cleaning work can be carried out easily.

Fig. 9 is a plan view showing opening/closing of the end covers 33 of the air coolers (intercooler 5 and aftercooler 6). Fig. 9 shows the example of the structure, it is designed that the end cover 33 at the air outlet end also doubles as a moisture separator for the coolers 5 and 6, which can be opened and closed. The end cover 33 is usually fixed on the flange of the cooler shell 35 with a screw 33a, and the fixing screw 33a can be removed when doing inspection and maintenance work, so as to allow the end cover 33 to be wound around the hinge frame 34 on the cooler shell 35 The hinge pin 34a rotates. Therefore, cleaning and inspection work is facilitated. In the structural arrangement of this embodiment, the rotation center of the hinge frame 34 is set at the front edge position of the end cover 33, so the required space for opening/closing the end cover 33 is the least. Since the hinge pin drawing hole 33b of the hinge frame 34 or the end cover 33 is an elongated hole, the hinge pin 34a can move slightly along the longitudinal direction Y1 when the end cover 33 is opened. Therefore, the "0" ring and gasket are protected from damage during the opening and closing action.

Fig. 10 shows the installation of a crane for inspection and maintenance. When the auxiliary equipment is overhauled, the front panel 52, the side panel 54, part of the outer frame 51, etc. are removed. The main column 36 of the pole crane is mounted on a support 28 located at the corner of the front plate 52 (or an extension thereof) and the side plate 54 (or an extension thereof). Swivel arm 37 is contained on the column 36, so hoist machine can winch each parts or equipment. The noise barrier cover and its frame 51 on the side of the side panel 54 are removable so that parts or equipment can be taken out in the same (open) direction. Rod lifts 36 , 37 and 38 may be housed within housing 50 . When the whole complete set of equipment 50 needs to be overhauled, the plates 22, 52, 53 and 54 constituting the box body 50 will be dismantled, and then, the other three uprights 39 (one of which cannot be seen in the figure) shown by dotted lines in the figure are together with the upright 36, Be installed on 4 bearings 28 on the base 21 (3 bearings are not shown in the figure). In addition, the beam 40 and the traveling mast 41 are mounted so as to be able to lift the various components in the plant 50 .

FIG. 11 shows the method of taking out or moving the intake pipe 18 . The flanges 18 a and 18 a are provided above the intake duct 18 so that the intake duct 18 is suspended from two beams 43 extending perpendicularly to the side plate 54 . The top panel 30 and the side panels 54 are to be opened or removed for maintenance work. Then, first remove the frame 42 between the outer frame 51 above the side plate 54 , and then pull the air intake pipe 18 toward the surface of the side plate 54 to remove the air intake pipe 18 . Since the flange portion 18a of the intake pipe 18 is slidable on the beam 43, it can be easily removed in the direction X1. After the intake pipe 18 is pulled out, the center above the side plate is open, so the parts in the complete set of equipment 50 are easily lifted out with a crane.

12A and 12B show the exhaust pipe 16 and the motor exhaust pipe 15 under no-load operation. The exhaust pipe 16 of built-in exhaust muffler 17 is made in the motor exhaust pipe 15, and it separates with the exhaust passage of motor 4. The air discharged from the compressors 1 and 2 during no-load operation is discharged through the exhaust muffler 17 , and then the exhaust gas flows out of the case 50 through the exhaust port 45 of the top plate 30 . The air discharged from the motor 4 after cooling the motor 4 passes through the motor exhaust pipe 15 through the motor exhaust port 44 . Then, the air is discharged out of the casing 50 through the motor exhaust port 46 . The inwall of motor exhaust pipe 15 is provided with sound-absorbing device 47, to isolate noise. Since the air exhausted from the motor 4 flows around the exhaust duct 16 before it exits the housing, noise transmission and heat radiation from the exhaust duct 16 into the housing 50 can be minimized. Since the exhaust port 45 is adjacent to the motor exhaust port, the hot exhaust gas from the plant 50 can be cooled by merging with the motor 4 exhaust gas.

According to the present invention, daily and routine inspection work can be easily performed, and the time for completing the inspection work can be shortened. In addition, the space required for maintenance work can be reduced, so that current restrictions on installation of equipment such as installation space and installation orientation can be reduced. Therefore, the design of the device can be more flexible.

Also, since maintenance work can be easily performed, maintenance and repair costs are reduced.

In addition, since the space for maintenance and repair is reduced, installation work can be performed relatively freely.

Because the entire cooler can be easily removed, the time required to complete service work is reduced. Maintenance costs are thus reduced.

Since the end cover of the air cooler is easy to open or close, the maintenance work of the air cooler can be conveniently carried out. Maintenance costs are thus reduced.

Since the maintenance space for the coolant cooler and the lubricating oil cooler can share the maintenance space for the air cooler, the space required for installing the compressor can be reduced.

Since the intake pipe can be easily removed, each component can be easily inspected and repaired during inspection and maintenance. Therefore, maintenance and repair costs are reduced.

Since equipment such as installation of a crane on the ceiling can be omitted, the cost required for installing the compressor can be reduced.

Reliability is improved because hot exhaust gas does not flow into the motor.

Since the space in the box can be fully utilized, the size of the complete set of equipment can be reduced and the maintenance work can be easily carried out.

Referring to Figs. 16 to 18, 20 and 21, a preferred embodiment mainly consisting of the rotor portion of the low pressure stage compressor and/or the high pressure stage compressor bodies 1 and 2 will be described below.

As shown in Figure 16, the convex rotor 101 with screw-shaped outer convex teeth 101a and the concave rotor 102 with screw-shaped inner concave teeth 102a are supported by bearings 152, so that the rotors 101 and 102 are mounted on the housing 151 in a non-contact manner. Rotate in the middle, but the teeth 101a and 102a of the rotors 101 and 102 are mated and meshed with each other, and 152 (not shown in the bearing diagram on the other side) is supported in the housing 151. The two rotors 101 and 102 are connected to each other by means of synchronous gears 153 and 154 .

The lobes 103 of the male rotor 101 and the female rotor 102 shown in FIG. 16 are heated to the same temperature as the PFA paint is baked, at which temperature the lobes 103 are degreased. Then, the surface of the rotor 104 made of, for example, carbon steel is roughened as indicated by symbol R in FIG. 17, which shows a part of the rotor base. The rough surface 104a is coated with a primer 105, which is then dried. Next, a PFA coating 106 is applied over the dried base coat 105, and the entire part is baked.

其中的x和n是正整数。例如，可从Mitsui Dupont Prolochemical公司买到商标与Dupont的Teflon PFA(商标)相同的材料。As disclosed in "LATEST FLUOROPOLYMER COATING TECHNOLOGY" (Fluoropolymer Coating New Technology) (published by Epote Co., Ltd.) p.p8 and p.p304, the structure of PFA is as follows:

Wherein x and n are positive integers. For example, materials with the same trademark as Dupont's Teflon PFA (trademark) are commercially available from Mitsui Dupont Prolochemical Company.

Figure 18 shows the process sequence of PFA coating in detail. First, the base body 104 of each lobe 103 on the screw rotor of each dry screw compressor 1 and 2 (see FIGS. 16 and 17 ). processed to a predetermined shape. Then, the base body 104 of the protruding teeth 103 is subjected to a heating and degreasing process 107 at the same temperature as when the PFA coating is baked. Next, the substrate 104 is cooled to the room temperature of the processing workshop, and the coating surface of the protruding teeth 103 substrate 104 is roughened by performing an aluminum blasting process 108 . Then, the rough surface 104a is cleaned by a scrubbing process 109, followed by a primer coating process 110, and the coating is composed of some materials, such as PFA particles, pigments and binders. Then step 111 dries the undercoat layer, and step 112 pre-bakes it at 300° C. to 350° C., and then cools it. Then, the coating step 113 of the PFA film is performed. After confirming that the PFA film has been dried in step 114, it is baked at a temperature of 390° C. to 420° C. (step 115 ). It is then allowed to cool (step 116), and the thickness of the PFA film layer 106 is measured. If the predetermined thickness is not achieved, the steps 113 to 116 in Fig. 18 are repeated to achieve the desired thickness.

Fig. 21 shows the process of forming the PFA coating. In this process, a primer solution 132 formed by mixing and interdiffusion of PFA particles 131, binder, pigment, and water is coated on the rough surface 104a of the rotor base 104 in the primer coating process 110 described above. After finishing the drying process 111 and the pre-baking process 112, in the process 113, the solution 134 of the PFA particles 131 is coated on the pre-baked bottom layer 105a, and then dried. In the next step 115 , the entire body is fired, so that the PFA particles are melted on the rotor base 104 to form continuous coating layers 105 , 106 . When PFA coating is performed, the change of the coating film itself is disclosed in the above "LATEST FLUOROPOLYMER COATING TECHNOLOGY" p.p104.

Then, the PFA coating according to the invention was compared with a conventional PTFE (polytetrafluoroethylene) coating.

Although the conventional process procedure for forming the PTFE coating is similar to that shown in FIG. 22, the PTFE particles 136 coated on the surface of the rotor base 104 are not melted, but the PTFE film 135 is formed by stacking maintaining their particle shape. Numeral 137 denotes a PTFE primer solution, 138 denotes a PTFE primer that has been prebaked or baked for a short time, and 139 denotes a PTFE coating main solution. The situation of PTFE film has also been disclosed in the above-mentioned "LATEST FLUOROPOLYMER COATING TECHNOLOGY" p.p104.

Although the corrosion resistance of the PTFE particles 136 is similar to that of the PEA particles 131, the fact that the PTFE coating film is simply piled up by the PTFE particles easily forms pores along the areas where the particles 136 and 136 are connected to each other. Therefore, the thickness of the PTFE coating film 135 must be thicker than that of the PFA film 106 in order to have satisfactory corrosion resistance. In other words, the PFA film 106 has satisfactory corrosion resistance even if its thickness is thin.

Then, the PFA coating according to the invention was compared with the conventional _MoS2 coating.

Figures 19 and 23 represent the traditional MoS ₂ coating process and the process of forming the MoS ₂ coating film.

In the _MoS2 coating process, after the degreasing process 118 and the shot blasting process 119 are completed, manganese phosphate treatment 120, water washing 121 and drying 122 are performed, so that a manganese phosphate coating film is formed on the rotor base 104. Then, the scrubbing step 123 is performed, followed by the MoS ₂ coating step 124 and the drying step 125 , so the dead leaf-shaped MoS ₂ particles 141 are accumulated. Then pre-baking 126 and baking process 127 are performed, and the MoS ₂ particles 141 are bonded together with a caking agent. The structure of the MoS ₂ coating is packed MoS ₂ particles 141 with the voids between the particles filled with a binder. If the adhesive and phosphate coating 140 are subjected to high temperatures above 200°C, their corrosion resistance will deteriorate. Therefore, pores are easily formed between the MoS ₂ particles 141 and 141 . Due to adiabatic compression, the air temperature in the compression chamber of the dry screw compressor sometimes rises above 200 °C, and the good corrosion resistance of the _MoS2 coating will not be maintained all the time.

The PFA coating, on the other hand, covers the surface of the rotor base 104 with a continuous uniform flow of PFA particles 131 that melt and solidify. Therefore, pores are not easily formed, so that satisfactory corrosion resistance can be obtained even if the thickness of the PFA coating film 106 is small (50 micrometers or less). Since the PFA particles 131 in the PFA coating layer 106 are melted and integrated, there is no fear of damaging the coating film layer 106 due to falling of the granular powder.

Due to the non-adhesive properties of PFA, when impurities (such as dust in the air) invade the small gap between the convex rotor 101 and the concave rotor 102, or invade the rotors 101, 102 and the compressor bodies 1 and 2, It is easy to be discharged when the compression chamber is between the shells 151. Therefore, there is no need to worry too much about clogging of the rotors 101 and 102 .

When the rotors 101 and 102 of the dry screw compressors 1 and 2 are coated with PFA as described above, rust in the rotors 101 and 102 can be prevented and a small gap between the rotors 101 and 102 can be avoided The inside or between the rotors 101 and 102 and the casing 151 is clogged due to rust. Thus, clogging of the rotors 101 and 102 due to rust can be avoided.

The curve of Fig. 20 shows the results of the rotation resistance or braking force measurement of the dry screw compressor rotor, the compressor rotor lobe is added with _MoS2 coating or PFA coating (Teflon PFA (trademark) of Mitsui DuPont Florochemical Co., Ltd.), The measurements were evaluated by the torque required to turn the rotors, which were periodically sprayed with salt water to force them to rust and clog the rotors. After comparing with the rotor with conventional MoS ₂ coating, the fact that the rotor with PFA coating can have a more satisfactory effect in preventing the rotor from rusting can be seen from Fig. 20 . So less worry about rotor clogging due to rust.

As mentioned above, if the PFA coating is added to the lobes of the screw rotor, the rusting of the lobes of the screw rotor can be minimized. Even if rust occurs in the casing, the non-adhesive property of fluororesin prevents the rotor from being braked by rust spots in the casing. As a result, braking of the rotor in the gas compression chamber due to rusting can be avoided.

Although the best form of the present invention has been described to a certain extent, it should be understood that the best form disclosed by the present invention can be changed without departing from the following claims in terms of structural details and the combination and arrangement of various parts. changes within the spirit and scope of the invention as described.

Claims (16)

1. A box-type complete set of screw compressors, including: Parts having: at least one compressor body; at least one gas cooler for cooling gas discharged from the compressor body; a coolant cooler for cooling a coolant used to cool the compressor body's shell; a an air inlet pipe for introducing uncompressed gas into the air inlet of the compressor body; and a control panel for regulating and displaying the operating conditions of the compressor body; and A box comprising a box-like frame and a plurality of panels, each panel having a front panel covering at least a portion of the front of the frame and side panels covering at least a portion of the sides adjacent to the front, the box containing substantially the above-mentioned components; It is characterized by: The compressor includes the front panel (52) and one of the side panels (54), the control panel (11) is mounted on the front panel (52); The plate (52) and one of the side plates (54) are provided with: An oil level gauge (57) showing the level of lubricating oil in the oil tank (3b), the oil tank (3b) stores lubricating oil, and the lubricating oil is used to lubricate the bearings (152) of the compressor body (1, 2); Lubricating oil is supplied to the oil supply port (58) of the oil tank (3b); A filter (13) for filtering lubricating oil supplied from the oil tank (3b) to the bearings (152) of the compressor body (1, 2); an oil cooler (7) for cooling said lubricating oil; and The condensate check valve (14c) installed on the branch pipe (14b) branched from the condensate discharge pipe (14a), which is used to discharge the compressed gas separated from the gas cooler (5, 6) of condensed water. 2. The box-type complete screw compressor according to claim 1, characterized in that: the front plate is divided into two parts, which are hinged on the ends far away from each other, and one of the two parts of the front plate is provided with an operation display showing the maintenance time screen, perform maintenance work within the time indicated. 3. The box-type screw compressor as claimed in claim 2, characterized in that: when the two front plate parts are closed, the two front plate parts can be connected together on a central frame, and the central frame is set Between the two front panel parts and designed to be detachable from said box frame. 4. The box-type screw compressor as claimed in claim 1, characterized in that: at least one compressor body is composed of a low-pressure stage compressor body and a high-pressure stage compressor body; at least one gas cooler is composed of It consists of an intercooler and an aftercooler. The intercooler is used to cool the low-pressure compressed gas discharged from the low-pressure stage compressor body and sucked into the high-pressure stage compressor body. The aftercooler is used to cool the high-pressure stage compressor body. The high-pressure compressed gas discharged from the main body, the intercooler and the aftercooler respectively have tube bundles, and the tube bundles are installed in their respective shells, and the tube bundles should be drawn out in the same direction as each other. 5. The box-type complete set of screw compressors according to claim 4, characterized in that: the tube bundle can be drawn out toward the front plate or the rear plate, and the front plate and the rear plate are at opposite positions of the box body. 6. The box-type complete set of screw compressors according to claim 4, wherein each gas cooler has casters that can move on rails, and the rails are installed in the box body. 7. The box-type screw compressor as claimed in claim 4, wherein each gas cooler has an end cover hinged on each cooler casing, and they can rotate relative to the casing around a pivot to open/close The opening of this case. 8. The box-type complete screw compressor according to claim 4, characterized in that: the coolant cooler and the lubricating oil cooler for cooling lubricating oil are designed to be taken out along the same direction as the tube bundle of the gas cooler. 9. The box-type complete screw compressor according to claim 1, characterized in that: the inlet pipe is designed to slide along the direction of closing the inlet pipe and moving out from one side plate. 10. The box-type screw compressor as claimed in claim 9, characterized in that the intake pipe is slidable along the beam, and the beam extends toward one side plate. 11. The box-type complete set of screw compressor according to claim 10, characterized in that: the air inlet pipe is connected to the air inlet of the compressor body through a rubber elbow, and the rubber variable pipe can be easily disassembled. 12. The box-type complete set of screw compressor according to claim 1, characterized in that: the fixed support for installing and maintaining the crane is made in the box body. 13. The box-type complete screw compressor according to claim 12, characterized in that: the fixed support is made at any one of the four corners of the box body on the base (21). 14. The box-type complete set of screw compressors according to claim 13, characterized in that: the rod crane installed on the above-mentioned fixed support is accommodated in the box. 15. The box-type complete set of screw compressors according to claim 1, characterized in that: the air discharge port for discharging gas when the compressor body is in no-load operation, and the discharge port for discharging the air flow after cooling the motor are separated from each other, and the motor Used to drive the compressor body. 16. A box-type complete set of screw compressors, including: Some parts, there is a low-pressure screw compressor body and a high-pressure stage screw compressor body, which are driven by a motor; an intercooler is used to cool the low-pressure compressor body discharged from the low-pressure stage compressor body and sucked by the high-pressure stage compressor body. Compressed gas; an aftercooler for cooling the high-pressure compressed gas discharged from the high-pressure stage compressor body; a coolant cooler for cooling the coolant used to cool the shells of the low-pressure stage and high-pressure stage compressor bodies ; an oil cooler for cooling the oil that lubricates the compressor body bearings; an air inlet duct for introducing uncompressed gas into the low pressure stage compressor body inlet; and a control panel for specifying the low pressure stage and the working conditions of the high-pressure stage compressors, and display the working conditions of the compressor body; and A box body comprising a box-like frame and a plurality of panels including a front panel covering at least a portion of the front of the frame and side panels covering at least a portion of the sides adjacent to the front and containing substantially the above-mentioned these parts; Characterized in that the bodies of the low-pressure and high-pressure stage screw compressors are configured such that their screw axes extend parallel to the front plate; The intercooler and the aftercooler are configured such that their longitudinal direction is substantially perpendicular to the above-mentioned axial direction, the intercooler is installed under the compressor body of the low pressure stage and the high pressure stage, and the aftercooler is installed under the body of the compressor body of the low pressure stage and the high pressure stage above; The lubricating oil cooler and the coolant cooler are located under the motor; The intake pipe is installed between the aftercooler and one of the side panels; The control board is installed at the position of the front board, opposite to the motor; and The condensate discharge pipe for condensate discharge is provided on a side plate with the condensate discharge outlet, and the condensate is separated from the compressed gas cooled by the intercooler and the aftercooler.

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