Self-acting valve of a piston compressor

Abstract

This utility model pertains to compressor engineering, specifically to the design of a self-acting piston compressor valve. The self-acting piston compressor valve comprises seats with fluid passages, elastic plates adjacent to the seats, and a stop, all held together by a sealing ring. A cavity is formed within the seat walls that does not intersect with the fluid passages. This utility model reduces the weight of the self-acting piston compressor valve while maintaining sufficient strength.

Description

[0001] The utility model relates to the field of compressor engineering, namely to the design of a self-acting valve for a piston compressor.

[0002] A straight-through valve for piston compressors is known (Author's Certificate No. 114304; M.I. Frenkel. Piston Compressors. Leningrad: Mashinostroenie, 1969, pp. 345-349), assembled from solid seats (without internal cavities in the body) with flow channels, adjacent elastic plates and clamping rings. Seats are made from cast iron, aluminum alloys and structural steels by casting and machining blanks.

[0003] Despite the advantages of self-acting straight-through valves, one of their drawbacks is the labor-intensive nature of valve assembly manufacturing. This involves the production of blanks (plates) and their subsequent machining, either individually or as part of a package, to form a surface for pressing in the seat ring. Seats are typically cast, resulting in heavy weight, high labor intensity, and low material utilization.

[0004] The technical problem is to eliminate the shortcomings of the state of the art and develop a design of a self-acting valve characterized by lower metal consumption, increased material utilization rate and reduced weight.

[0005] The technical result is a reduction in the weight of the self-acting valve of a piston compressor while maintaining sufficient strength.

[0006] A self-acting piston compressor valve comprises seats with fluid passages, elastic plates adjacent to the seats, and a stop, all held together by a sealing ring. The technical problem is solved and the technical result achieved by creating a cavity within the seat walls that does not intersect with the fluid passages.

[0007] The cavity is U-shaped and runs along three sides of the saddle.

[0008] Fig. 1 shows a perspective view from the front of the seat of the self-acting valve of the piston compressor according to the utility model.

[0009] Fig. 2 shows a perspective view from behind the seat of a self-acting valve of a piston compressor according to the utility model.

[0010] Fig. 3 shows a perspective view from the front of the self-acting valve seat, which clearly shows the volume of the cavities being filled.

[0011] Fig. 4 shows an axonometric view from behind the seat of a self-acting valve, which clearly shows the volume of the cavities created.

[0012] Fig. 5 schematically shows a series of cross-sections of the seat of a self-acting valve at various places along its length.

[0013] Fig. 6 schematically shows a series of longitudinal sections of a self-acting valve at different locations along its height.

[0014] Fig. 7 shows a strength calculation for the seat of a self-acting valve of known design.

[0015] Fig. 8 shows the strength calculation for the seat of a self-acting valve according to the utility model.

[0016] The figures indicate the following positions:

[0017] 1 - fluid channels; 2 - cavity; 3 - top side; 4 - side side; 5-8 - cross-sections; 9-11 - longitudinal sections; L - direction along the length of the seat; H - direction along the height of the seat.

[0018] As is well known, a straight-through, self-acting piston compressor valve comprises a series of seats, between which elastic plates that bend under pressure are clamped, along with a stop, held together by sealing rings. The seats contain inlet channels (fluid channels) 1, through which the working fluid flows and pushes the plate toward the stop surface. These surfaces are present in both the seat and the stop and are designed to reduce plate travel and ensure valve operation. The series of seats and plates are assembled into a stack, with a stop in the center, onto which the plates bend. The outer seats may have a different geometry from the intermediate seats and are more commonly referred to as a side plate. The assembled stack is sealed with a sealing ring on both sides and then installed in the piston compressor.

[0019] According to the utility model, in order to reduce the valve's weight, one or more cavities 2 are provided within the seat walls, which do not communicate (do not intersect) with the specified fluid channels 1. These cavities 2 in the seat body may be separate from one another, or they may communicate with one another.

[0020] Preferably, a single cavity 2 of a U-shape is formed in the walls of the seat (see Fig. 3, 4) and extends along the upper side 3 and two lateral sides 4 of the seat. In particular, according to Fig. 3-6, the cavity 2 extends along the length L of the seat in the direction across the channels 1 for the fluid. In addition, the cavity 2 extends along the height H of the seat, in the direction along the channels 1 for the fluid.

[0021] Thus, the cavity 1 or cavities, i.e. the exclusion of the internal volume of material, are provided in the areas of the seat where the channels 1 for the fluid do not pass.

[0022] For clarity, Figs. 5 and 6 show the seat and a number of its cross-sections 2-8. In particular, sections 5 and 6 (Fig. 5) demonstrate the exclusion of volume from the side portions of the seat that do not have inlet channels, i.e., in this location, cavity 2 extends along the height H of the seat. Sections 7 and 8 show the location of the cavity along the length L of the seat, i.e., the exclusion of volume in the upper portion of the seat that does not have inlet channels.

[0023] Channel 2 along the upper side 3, shown in section 8 in Fig. 5, is the minimum possible volume excluded from the seat body along its entire length L, due to the thinning in the section with the inlet channel and the channel for the working fluid outlet. The channels in sections 5 and 6 are conditioned by minimizing the material used by eliminating material to acceptable values. In these sections, the force from the working fluid pressure is no longer present, but the force from the sealing ring remains.

[0024] Similarly, in Fig. 6, in longitudinal sections 9, a cavity in the upper part of the saddle is shown, running along the length L of the saddle, and in longitudinal sections 10, 11, cavities in the side parts of the saddle, running along the height H of the saddle, are shown.

[0025] In Figs. 3 and 4, for clarity, the seat walls are shown as a translucent fill, and cavity 2, created in the seat wall, i.e., the volume that could theoretically be excluded from the seat body without changing the valve's strength properties, is shown as a solid gray fill. These views particularly clearly show the U-shaped shape of cavity 2.

[0026] Figure 7 shows a strength calculation for the seat of a self-acting straight-through valve of a known design made of Steel 45 (GOST 1050-2013). The scale on the right shows the safety factor values. The design has a minimum safety factor of 8.2 at a pressure drop of 2.5 MPa, which is excessive. The scale on the right shows the safety factor values.

[0027] Figure 8 shows the strength calculation for a seat with cavity 2 (with volume excluded) made of the same material. The volume of cavity 2 is 33% of the original volume of the seat walls. The scale on the right shows the safety factor values. The minimum safety factor is 4.8, which is satisfactory.

[0028] Seats of the self-acting valve of the piston compressor can be made of any suitable material, in particular, from steel 45 GOST 1050-2013, steel 4140 ASTM A29 / A29M, etc. The seats are given a certain geometry, determined by ensuring the operating characteristics of the valve, affecting the performance of the piston compressor.

[0029] The seat blanks can be cast and then machined to form the fluid channels 1 and the cavity 2. However, it is difficult to form the cavities 2 in a complex shape in this way, such as in Fig. 3-6.

[0030] Seats are preferably manufactured using layer-by-layer 3D printing. This method allows for the production of seats with any configuration of channels 1 and cavity 2. The use of additive manufacturing in seat manufacturing solves a number of problems associated with traditional manufacturing methods. Specifically, it becomes possible to ensure the optimal channel 1 geometry for the valve's operating conditions without the limitations of machining and tooling preparation for casting. It is possible to achieve the closest possible geometry for final machining of valve seats, reducing the cost of manufacturing a valve assembly by eliminating the bulk of machining and tooling. Furthermore, it is possible to manufacture seats with a complex cavity or cavities 2 to eliminate as much material as possible. To eliminate volume when casting a seat, it is only possible to eliminate a channel of a fixed cross-section along its entire length.

[0031] Theoretically, the volume (and mass) removed from the seat body can reach 33% of the seat volume after machining the valve assembly. This is not the limit for this type of product. However, exceeding this figure is not recommended due to the reduced strength of the suction channel cross-section, as well as the rigidity of the valve structure. This can lead to a decrease in valve tightness and, consequently, valve efficiency. A volume reduction of less than 10% seems impractical from a technological standpoint. A reduction of 20% can be considered the lower limit that can be achieved in casting, for example, by removing the volume in cross-section 6 (see Fig. 5) along the seat length L.

[0032] The calculation performed, taking into account the operating pressure on the seat, shows that a solid seat has a minimum safety factor of approximately 8.2, while for a seat with an internal volume excluded by 33%, this figure is 4.8. Moreover, the wall thickness in the weakest section between the empty cavity and the surface of the suction channel is 1.6 mm.

[0033] It's possible to completely eliminate the internal volume, which doesn't affect seat strength or valve rigidity, or to add supports for highly loaded seats. Modern printing ensures that the volume is filled with supports starting from 5%, resulting in weight reduction.

[0034] The greatest load is experienced directly by the intake ports and the theoretical wall thinning behind them. Therefore, the minimum thickness should be calculated using the formula for the ultimate compressive stress. Then, based on strength conditions, a decision can be made on the volume excluded from the seat body.

[0035] In general, additive manufacturing of seat blanks with complex working surface geometries minimizes the amount of machining required for both the component itself and the valve assembly. Creating an internal cavity 2 in the seat walls, eliminating the internal volume that does not significantly affect the valve's strength and performance characteristics, reduces the weight and volume of material used in its manufacture.

Claims

1. A self-acting valve for a piston compressor, comprising seats with channels for a fluid medium, elastic plates adjacent to the seats and a limiter, held together by means of a sealing ring, characterized in that a cavity is formed inside the walls of the seat that does not intersect with the said channels for a fluid medium.

2. A self-acting valve according to paragraph 1, characterized in that the cavity is U-shaped and extends along three sides of the seat.

Images