Process screw compressor unloading structure and end face valve

Abstract

The application discloses a process screw compressor unloading structure and an end face valve, and relates to the technical field of process screw compressors. The unloading structure is arranged on the end face valve of the process screw compressor and comprises a valve cover arranged on the end face valve of the process screw compressor, a valve cover valve plate groove and a valve cover exhaust structure being arranged on the valve cover. A valve seat is arranged on the end face valve of the process screw compressor, and the valve seat is provided with a valve seat valve plate groove and a valve seat exhaust structure corresponding to the valve cover. The valve cover valve plate groove and the valve cover exhaust structure and the valve seat valve plate groove and the valve seat exhaust structure respectively form a valve plate cavity and an exhaust flow channel. A valve plate is arranged in the valve plate cavity. A compression component is arranged between the valve cover and the valve seat, and is provided with a preset pressure for pressing the valve plate in the valve plate cavity against the valve cover. The unloading structure is used for realizing the unloading of the process screw compressor, and then realizing the low-load or even no-load operation of the process screw compressor, so that no additional external leakage is generated, and the compressor can work under the rated exhaust pressure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of screw compressors, and particularly relates to a process screw compressor unloading structure and an end face valve. BACKGROUND

[0002] In a process flow, compression technology plays an indispensable role, and providing high-pressure gas is the main function of a compressor. Screw compressors are widely used in process flows due to their high single-stage pressure ratio, wide flow range, compact structure, and few wearing parts. However, in order to reduce the starting current, the compressor usually needs to be able to unload during startup. For a reciprocating compressor structure, the exhaust valve can freely adjust the exhaust pressure.

[0003] During the startup phase of the compressor, the current of the motor is 5-7 times the rated current, which may cause damage to the power equipment, so it is necessary to reduce the starting current as much as possible. Unloading the compressor during the startup phase is an effective method to reduce the starting current of the motor. The working principle of a process screw compressor is that the male and female rotor cavities and the casing form a closed volume, and during the rotation of the rotor, the closed volume gradually decreases, thereby achieving compression of the working medium. For a screw compressor, the exhaust pressure is not adjusted by an exhaust valve but is determined by the shape of the exhaust orifice. Once the exhaust orifice is designed, the volume ratio is determined. Even if the exhaust back pressure is lower than the rated exhaust pressure, the compression process in the compressor still exists, and the pressure of the working medium will still rise to the rated exhaust pressure and then decrease to the actual exhaust pressure. Therefore, the screw compressor cannot be unloaded and run, and there will always be a compression process inside.

[0004] The utility model patent with the publication number "CN219220730U" discloses a screw compressor slide valve mechanism, which comprises a slide valve, a slide valve rod, and a piston. The slide valve is installed in the slide valve cavity of the screw compressor body. The slide valve cavity is connected with the notch for accommodating the slide valve positioning key. The top of the slide valve positioning key is provided with a guide limiting strip. The slide valve positioning key is placed in the notch of the screw compressor body, and the guide limiting strip on the slide valve positioning key is matched with the key groove on the slide valve. The slide valve tray is fixed to the end face of the screw compressor body, and the slide valve tray abuts against the outer end face of the slide valve positioning key. The slide valve tray is matched with the slide valve.

[0005] This patent is a typical screw compressor slide valve mechanism. When pressure acts on the piston, the piston drives the slide valve rod to control the movement of the slide valve. When the slide valve moves, the position of the slide valve changes, thereby changing the effective working length of the rotor and further changing the exhaust capacity of the screw compressor. Alternatively, the position of the exhaust orifice is changed, thereby changing the volume ratio of the screw compressor. Figure 1It is a structural schematic view of a slide valve mechanism of a screw compressor.

[0006] The slide valve structure in the existing refrigeration screw compressor is not applicable to the process screw compressor, and the reasons are as follows:

[0007] The refrigeration screw compressor is generally of a liquid injection type, and there is liquid lubrication in the compression chamber, so that the slide valve can move normally, but in the oil-free environment, the slide valve is easily stuck to lose the function of regulating the load.

[0008] The slide valve structure will cause the increase of the external leakage of the compressor, and the refrigeration compressor is generally of a semi-closed or fully-closed structure, and the external leakage of the refrigerant will not cause the impact on the environment, but the process compressor is mostly of an open structure, and the compressed working medium is mostly a gas harmful to the environment, so that the slide valve structure is not applicable to the process screw compressor. SUMMARY

[0009] To solve the above technical problems, the application provides a process screw compressor unloading structure and an end face valve, the unloading structure is arranged on the end face valve, the pressure behind the end face valve is the exhaust back pressure, the pressure in front of the valve is the pressure in the compression chamber, the opening and closing of the valve plate can be controlled by the exhaust back pressure behind the valve, when the valve plate is opened, the gas in the compression chamber can directly enter the exhaust chamber through the valve hole, and the unloading operation of the screw compressor is realized.

[0010] The purpose of the application is realized by the following technical scheme, a process screw compressor unloading structure arranged on an end face valve of a process screw compressor, comprising:

[0011] A valve cover arranged on the end face valve of the process screw compressor, the valve cover is provided with a valve cover valve plate groove and a valve cover exhaust structure.

[0012] A valve seat arranged on the end face valve of the process screw compressor, the valve seat is provided with a valve seat valve plate groove and a valve seat exhaust structure corresponding to the valve cover, and the valve cover valve plate groove and the valve cover exhaust structure and the valve seat valve plate groove and the valve seat exhaust structure respectively form a valve plate cavity and an exhaust flow channel, and the valve plate cavity is communicated with an exhaust chamber through the exhaust flow channel.

[0013] A valve plate arranged in the valve plate cavity.

[0014] A compression component arranged between the valve cover and the valve seat, and pre-set with a pressure to press the valve plate in the valve plate cavity on the valve cover.

[0015] Preferably, the valve cover valve plate groove and the valve seat valve plate groove are crescent-shaped groove bodies, the valve cover valve plate groove is symmetrically arranged on the two sides of the valve cover, and the valve seat valve plate groove is symmetrically arranged on the two sides of the valve seat.

[0016] Preferably, the valve cover exhaust structure comprises a valve cover exhaust flow channel and an exhaust hole, and the valve seat exhaust structure comprises a valve seat exhaust flow channel; wherein the valve cover exhaust flow channel is connected to the bottom of the two valve cover valve piece grooves, and the exhaust hole is arranged inside the valve cover valve piece groove; the valve seat exhaust flow channel is connected to the bottom of the two valve seat valve piece grooves.

[0017] Preferably, the outer edge of the valve cover is provided with a sealing groove, and a sealing ring is arranged in the sealing groove.

[0018] Preferably, the valve piece comprises a valve head, a support structure and a valve tail; wherein the valve head is arranged in the valve cover valve piece groove, the valve tail is arranged in the valve seat valve piece groove, and the support structure is arranged between the valve head and the valve tail to separate the valve head from the valve tail.

[0019] Preferably, the compression component at least comprises a support spring, and when the compression component is a support spring, a plurality of support spring holes are arranged on the valve seat valve piece groove, and the support spring is fixed on the valve seat valve piece groove through the support spring hole.

[0020] Preferably, the front end surface of the valve head is in the same plane as the front end surface of the valve cover.

[0021] Preferably, a stepped hole is arranged on the valve cover valve piece groove, and a fillet is arranged on the stepped hole.

[0022] Preferably, the size of the valve piece is smaller than the size of the valve piece cavity.

[0023] The application provides a process screw compressor unloading structure and an end face valve.

[0024] Compared with the prior art, the application has the following advantages:

[0025] The process screw compressor unloading structure and the end face valve provided by the application are simple in structure, the end face valve is installed on the exhaust end face, and the integrity of the screw compressor cylinder is ensured.

[0026] By integrating the unloading structure provided by the present invention into the end-face valve structure, the compressor does not have additional external leakage clearance, ensuring the safe operation of the process compressor. The present invention enables unloaded operation of the process screw compressor, reducing the power consumption of the compressor during unloaded operation. The present invention utilizes the unloading structure to achieve unloading of the process screw compressor, thereby enabling low-load or even no-load operation of the process screw compressor without generating additional external leakage and without affecting the compressor's operation at rated exhaust pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a screw compressor slide valve mechanism in the prior art;

[0028] Figure 2 Schematic diagram of the explosion of the valve structure of the process screw compressor in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the valve cover structure in an embodiment of the present invention;

[0030] Figure 4 Schematic diagram of the valve seat structure in an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the valve plate structure in an embodiment of the present invention;

[0032] Figure 6 It is a schematic cross-sectional view of the process screw compressor valve structure along a plane perpendicular to the axis of the male rotor in an embodiment of the present invention.

[0033] In the figure, 1 is the front end cover of the intake air; 2 is the intake seat; 3 is the rotor; 4 is the casing; 5 is the valve cover; 6 is the valve disc; 7 is the support spring; 8 is the sealing ring; 9 is the valve seat; 10 is the valve cover fastening bolt; 11 is the valve disc cavity; 501 is the valve cover valve disc groove; 502 is the valve cover exhaust flow channel; 503 is the valve cover bolt hole; 504 is the exhaust hole; 505 is the sealing groove; 601 is the valve head; 602 is the supporting structure; 603 is the valve tail; 901 is the valve seat valve disc groove; 902 is the valve seat exhaust flow channel; 903 is the valve seat bolt hole; 904 is the support spring hole. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0035] like Figure 2 As shown, the technical solution of the present invention provides a process screw compressor unloading structure, which is arranged on the end face valve of the process screw compressor. The unloading mechanism includes:

[0036] The valve cover 5 is provided on the end face valve of the process screw compressor. The valve cover 5 is provided with a valve cover valve plate groove 501 and a valve cover exhaust structure.

[0037] The valve seat 9 is arranged on the end face valve of the process screw compressor. The valve seat 9 is provided with a valve seat valve plate groove 901 and a valve seat exhaust structure corresponding to the valve cover 5. The valve cover valve plate groove 501 and the valve cover exhaust structure and the valve seat valve plate groove 901 and the valve seat exhaust structure respectively constitute a valve plate cavity 11 and an exhaust flow channel. The valve plate cavity 11 is connected with the exhaust cavity through the exhaust flow channel.

[0038] The valve plate 6 is arranged inside the valve plate cavity 11 .

[0039] The compression component is arranged between the valve cover 5 and the valve seat 9 and has a preset pressure to press the valve disc 6 in the valve disc cavity 11 against the valve cover 5 .

[0040] like Figures 3-4 As shown, in one embodiment of the present invention, the valve cover valve disc groove 501 and the valve seat valve disc groove 901 are crescent-shaped groove bodies, the valve cover valve disc groove 501 is symmetrically arranged on both sides of the valve cover 5, and the valve seat valve disc groove 901 is symmetrically arranged on both sides of the valve seat 9.

[0041] As a further optimization of the above embodiment, the valve cover exhaust structure includes a valve cover exhaust channel 502 and an exhaust hole 504, and the valve seat exhaust structure includes a valve seat exhaust channel 902; wherein, the valve cover exhaust channel 502 connects the bottom of the two valve cover valve plate grooves 501, and the exhaust hole 504 is arranged inside the valve cover valve plate groove 501; the valve seat exhaust channel 902 connects the bottom of the two valve seat valve plate grooves 901.

[0042] like Figure 2 As shown, in one embodiment of the present invention, a sealing groove 505 is provided on the outer edge of the valve cover 5 , and a sealing ring 8 is provided in the sealing groove 505 .

[0043] like Figure 5 As shown, in one embodiment of the present invention, the valve disc 6 includes a valve head 601, a support structure 602 and a valve tail 603; wherein, the valve head 601 is arranged in the valve cover valve disc groove 501, the valve tail 603 is arranged in the valve seat valve disc groove 902, and the support structure 602 is arranged between the valve head 601 and the valve tail 603 to separate the valve head 601 from the valve tail 603.

[0044] In one embodiment of the present invention, the compression component includes at least a support spring 7. When the compression component is a support spring 7, a plurality of support spring holes 904 are provided on the valve seat valve disc groove 901, and the support spring 7 is fixed on the valve seat valve disc groove 901 through the support spring holes 904.

[0045] In one embodiment of the present invention, the front end surface of the valve head 601 and the front end surface of the valve cover 5 are in the same plane.

[0046] In one embodiment of the present application, the valve cover valve piece groove 501 is provided with a stepped hole, and the stepped hole is chamfered.

[0047] In one embodiment of the present application, the valve piece 6 is smaller than the valve piece cavity 11.

[0048] In one preferred embodiment of the present application, the structure of each part in the compressor unloading mechanism and the end face valve structure is as shown in Figures 2-6 The end face valve structure includes: a suction front end cover 1, a suction seat 2, a rotor 3, a casing 4, a valve cover 5, a valve piece 6, a support spring 7, a sealing ring 8, a valve seat 9, and a valve cover fastening bolt 10. The valve seat 9 is provided with a valve seat valve piece groove 901 and a support spring hole 904, the support spring 7 is installed in the support spring hole 904, the valve cover 5 is also provided with a valve cover valve piece groove 501, the two valve piece grooves form a valve piece cavity 11, the valve piece 6 is arranged in the valve piece cavity 11 and pressed on the support spring 7, the inner side of the valve cover 5 has a sealing groove 505, and the sealing ring 8 is installed in the sealing groove 505 to prevent leakage. The valve cover 5 and the valve seat 9 have an exhaust flow channel that connects the valve piece cavity 11 and an exhaust cavity, when the valve piece 6 is opened, the gas in the compression cavity flows through the valve piece cavity 11 and the exhaust flow channel into the exhaust cavity through the exhaust hole 504, realizing the unloading operation of the compressor.

[0049] In this embodiment, the valve cover 5 is provided with a crescent-shaped exhaust hole 504 and a valve cover valve piece groove 501, and a valve cover exhaust flow channel 502 is opened at the position of the valve cover valve piece groove 501 close to the exhaust cavity. The valve seat 9 is provided with a valve seat valve piece groove 901 corresponding to the valve cover 5, and also has a valve seat exhaust flow channel 902 at the position close to the exhaust cavity. The valve seat 9 is machined with four valve seat bolt holes 903, and the valve cover 5 has four valve cover bolt holes 503 at the corresponding position, the valve cover fastening bolt 10 passes through the two bolt holes to fix the valve cover on the valve seat 9, the valve cover valve piece groove 501 and the valve seat valve piece groove 901 form a valve piece cavity 11, the valve cover exhaust flow channel 502 and the valve seat exhaust flow channel 902 form a complete exhaust flow channel, and the valve piece cavity 11 is connected with the exhaust cavity through the exhaust flow channel. The valve seat 9 has eight support spring holes 904 in the valve seat valve piece groove 901 on both sides, and the valve piece support spring 7 is installed in the support spring hole 904. After the valve cover 5 and the valve seat 9 are fastened, the valve piece 6 is pressed onto the valve piece support spring 7, the support spring 7 has a certain pre-compression amount, providing a thrust to the valve piece 6, so that the valve piece 6 is tightly attached to the valve cover 5, and the valve head 601 of the valve piece 6 is in the same plane as the front end face of the valve cover 5. The valve cover 5 has a sealing groove 505 on the outer edge, and after the valve cover 5 and the valve seat 9 are fastened, the sealing ring 8 will be pressed in the sealing groove 505 to prevent process gas from leaking into the environment. The plane roughness of the support structure 602 of the valve piece 6 in contact with the valve cover valve piece groove 501 is required to be Ra<0.2μm, the stepped hole of the valve cover valve piece groove 501 is chamfered, and the valve piece 6 can be smoothly closed.

[0050] In this embodiment, the valve seat 9 and the exhaust seat are integrated, the valve cover valve piece groove 501 and the valve seat valve piece groove 901 constitute a complete valve piece cavity 11, the valve piece 6 moves in the valve piece cavity 11, the valve cover exhaust flow channel 502 and the valve seat exhaust flow channel 902 constitute a complete exhaust flow channel. Four through holes are processed on the valve seat 9, and four bolt holes are opened on the corresponding positions of the valve cover 5. The valve piece 6 is crescent-shaped, and the valve piece 6 has a support structure 602 in the middle, which divides the valve piece 6 into a valve head 601 and a valve tail 603, the valve tail 603 is installed in the valve seat valve piece groove 901 of the valve seat 9, and the size of the valve piece 6 is slightly smaller than the valve piece groove, so that the valve piece 6 can move up and down in the sliding groove without restriction. The valve piece support spring 7 is installed in the support spring hole 904 of the valve seat 9, the support structure 602 of the valve piece 6 is pressed above the valve piece support spring 7, and the valve piece support spring 7 provides support force for the valve piece 6. In this embodiment, the inner diameter of the valve piece cavity 11 is slightly larger than the outer diameter size of the valve piece support structure 602, so as to ensure that the movement of the valve piece 6 in the valve piece cavity 11 is not restricted. The valve piece 6 is pressed to the valve cover 5 by the support spring 7, and the front surface of the valve head 601 on the valve piece 6 coincides with the exhaust end surface of the valve cover 5. The front surface of the support structure 602 of the valve piece 6 is a sealing surface, and the roughness requirement is Ra<0.2 μm. The valve piece 6 needs to be treated by wear-resistant self-lubricating spraying to reduce friction loss and thus cause poor sealing performance.

[0051] In the example of the present application, the working principle of the valve structure is as follows: when the exhaust back pressure is less than the rated exhaust pressure of the compressor, the pressure in the compression cavity will be greater than the pressure in the valve piece cavity 11 at a certain moment, the pressure of the working medium on the valve piece 6 exceeds the pre-pressure of the valve piece support spring 7, and the valve piece 6 is opened, the working cavity of the compressor is communicated with the exhaust cavity through the valve cover exhaust hole 504, the valve piece cavity 11 and the exhaust flow channel, the compressor is pre-exhausted, at this time the gas pressure in the working cavity no longer increases, and the unloading of the compressor is realized. When the exhaust back pressure of the compressor gradually increases, the pressure in the valve piece cavity 11 also increases, the thrust of the valve piece 6 by the working medium gradually decreases, the valve piece 6 falls back under the support of the valve piece support spring 7, until the exhaust back pressure is equal to the rated exhaust pressure, the valve piece 6 is completely closed, and the compression process in the compressor returns to normal.

[0052] In addition to providing a process screw compressor unloading structure in the technical scheme of the present application, an end face valve structure is further provided, as shown in Figure 2 , which comprises a suction front end cover 1, a suction seat 2, a rotor 3, a casing 4, a valve cover 5, a valve piece 6, a compression component 7, a valve seat 9 and a valve cover fastening bolt 10, the valve cover 5, the valve piece 6, the compression component 7 and the valve seat 9 of the end face valve adopt the above-mentioned compressor unloading structure.

[0053] In the present application, the connection relationship of each part of the end face valve is a conventional design, which will not be repeated here, and details can be found in Figure 2 .

[0054] The above are preferred embodiments of the present application. It should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the scope of protection of the present application.

Claims

1. A process screw compressor unloading structure provided on a process screw compressor end face valve, characterized by: The unloading structure comprises: A valve cover (5) is arranged on the end face valve of the process screw compressor, and a valve cover valve plate groove (501) and a valve cover exhaust structure are arranged on the valve cover (5); A valve seat (9) is arranged on the end face valve of the process screw compressor, and a valve seat valve plate groove (901) corresponding to the valve cover (5) and a valve seat exhaust structure are arranged on the valve seat (9), the valve cover valve plate groove (501) and the valve seat valve plate groove (901) constitute a valve plate cavity (11), the valve cover exhaust structure and the valve seat exhaust structure constitute an exhaust flow channel, and the valve plate cavity (11) is communicated with an exhaust cavity through the exhaust flow channel; A valve plate (6) is arranged inside the valve plate cavity (11); A compression component is arranged between the valve cover (5) and the valve seat (9), and is pre-set with a pressure to press the valve plate (6) in the valve plate cavity (11) tightly on the valve cover (5); The valve cover valve plate groove (501) and the valve seat valve plate groove (901) are crescent-shaped groove bodies, the valve cover valve plate groove (501) is symmetrically arranged on both sides of the valve cover (5), and the valve seat valve plate groove (901) is symmetrically arranged on both sides of the valve seat (9); The valve plate (6) comprises a valve head (601), a support structure (602) and a valve tail (603); wherein the valve head (601) is arranged in the valve cover valve plate groove (501), the valve tail (603) is arranged in the valve seat valve plate groove (901), and the support structure (602) is arranged between the valve head (601) and the valve tail (603) to separate the valve head (601) from the valve tail (603); The compression component at least comprises a support spring (7), when the compression component is the support spring (7), a plurality of support spring holes (904) are arranged on the valve seat valve plate groove (901), and the support spring (7) is fixed on the valve seat valve plate groove (901) through the support spring holes (904).

2. A process screw compressor unloading arrangement as claimed in claim 1, characterized in that: The valve cover exhaust structure comprises a valve cover exhaust flow channel (502) and an exhaust hole (504), and the valve seat exhaust structure comprises a valve seat exhaust flow channel (902); wherein the valve cover exhaust flow channel (502) is connected to the bottom of the two valve cover valve plate grooves (501), the exhaust hole (504) is arranged inside the valve cover valve plate groove (501), and the valve seat exhaust flow channel (902) is connected to the bottom of the two valve seat valve plate grooves (901).

3. A process screw compressor unloading arrangement as claimed in claim 2, characterised in that: A sealing groove (505) is arranged on the outer edge of the valve cover (5), and a sealing ring (8) is arranged in the sealing groove (505).

4. A process screw compressor unloading arrangement as claimed in claim 3, characterised in that: The front end surface of the valve head (601) is in the same plane as the front end surface of the valve cover (5).

5. A process screw compressor unloading arrangement as claimed in claim 4, characterised in that: A stepped hole is arranged on the valve cover valve plate groove (501), and a fillet is arranged on the stepped hole.

6. A process screw compressor unloading arrangement as claimed in claim 5, characterised in that: The size of the valve plate (6) is smaller than the size of the valve plate cavity (11).

7. A face valve structure provided on the exhaust face of a process screw compressor, comprising a suction front cover (1), a suction seat (2), a rotor (3), a casing (4), a valve cover (5), a valve plate (6), a compression element, a valve seat (9) and a valve cover fastening bolt (10), characterized in that: The valve cover (5), the valve plate (6), the compression component and the valve seat (9) of the end face valve adopt the compressor unloading structure of any one of claims 1-6.

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