RU2505706C1 - Automatic combined valve of piston compressor - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed combined valve comprises circular seat with at least suction valve at periphery and discharge orifice. Circular suction plate is arranged between piston stage cylinder and seat. Discharge element is connected with stroke limiter. Suction plate has elastically wrought tabs. Said tabs are arranged in circle to make spring sections there between to make said tabs overlap said suction orifices.

EFFECT: smaller flow section, simplified design and manufacture.

Description

The invention relates to the field of compressor engineering, namely to self-acting combined valves of reciprocating compressors.

Combined ring valves are known (see Refrigeration compressors / A.V. Bykov, E.M. Bezhanishvili, I.M. Kalnin, etc.; edited by A.V. Bykov. - 2nd ed., Revised and add. - M .: Kolos, 1992, pp. 72-73). In their design there are suction ring plates with springs for closing the valve. The input of the working fluid (RT) into the cylinder occurs along the inner ring zone of the plate. An injection annular plate with a stroke limiter of such a valve is installed along the belts of the saddle and the disk as part of the water hammer discharge device.

The springs in the valve assembly are heterogeneous in characteristics and unevenly load the plate. In a real valve, the work is accompanied by friction of the plates along the guides, a skewed movement, and the consequent uneven wear of the sealing belts of the saddle and the edges of the plates, which subsequently break the tightness. The suction valve gives the working chamber of the stage increased dead space, which reduces the performance of the compressor. The valve unloading device in the mode of hydraulic shock is triggered with large shock loads, which lead to knocks in the machine.

Combined valves of the petal type of suction and discharge plates are also known, in which the petals are combined in one of the diameters (see PI Plastinin Reciprocating Compressors, vol. 2: Design Basics. - M .: Kolos, 2008, p. 274) .

The composition of these flap valves employs three different sizes of plates: one for suction and two for discharge. In addition, the placement of the discharge plates of the valve leaves a large dead volume in the channels of the seat, from which the working fluid expands after discharge, reducing the performance of the compressor. The design of the combined valve does not provide for unloading from hydraulic shocks that occur during wet running, since one of the known methods of protection is assumed (maintaining a significant amount of superheating of the steam at the suction; dosed filling of the working agent; use of liquid separators with an automation system that provides for compressor emergency shutdown unacceptable fluid level; piping with necessary slopes).

Closest to the proposed is a combined compressor valve with an annular suction plate installed between the compressor cylinder and the seat with the possibility of overlapping the annular suction hole between them, and a discharge cylindrical element with a sealing girdle on the outer diameter in contact with the sealing girdle of the central pressure opening of the saddle, working together with a device for unloading from water hammer - a stroke limiter of a discharge element made in the form of a spring installed between the discharge element and the valve cover (see US 6044862 (A), IPC F04B 39/10, F16K 15/14, F16K 15/00. Compressor reed valve / Schumann Stanley P, Wallis Frank Shue, Beresik Jason Patrick, et al., 04.04.2000).

The disadvantage of this design is the limited flow area of the suction and discharge valves due to the fact that the suction valve has an uneven stroke of the plate relative to the sealing belts, and in the discharge valve, gas is released only along the outer sealing belt of the disk. The device for unloading from hydraulic shocks does not provide for a reduction in shock loads in wet conditions.

The technical result of the invention is to increase the flow area of the valves, reducing the number of elements, simplifying the manufacturing and assembly of individual parts, effective protection against water hammer, and, as a result, improving reliability and durability.

The technical result of the invention is achieved due to the fact that the self-acting combined valve for a reciprocating compressor contains an annular seat with at least one suction hole on the periphery and a discharge hole, an annular suction plate is installed between the piston stage cylinder and the seat, and the discharge element is connected with stroke limiter, and the suction plate is made with elastically deformable petals located along the ring with the formation of spring between the petals sections with the possibility of overlapping by the petals of the suction holes.

The implementation of the suction plate with elastically deformable petals allows you to increase the intake cross-section (since in this case the extreme position of the petals is almost parallel to the seat plane, in contrast to analogues having cantilevered petals) and to ensure uniform movement of the petals of the plate relative to the sealing belts due to the absence of friction plates about valve parts.

In addition, the injection hole has an annular shape and is formed by a saddle and a disk connected to the stroke limiter, and the discharge element is made in the form of a round plate with at least one hole in the region of the edge of the disk, which allows to increase the discharge passage section due to that the gas escapes not only along the edge of the discharge plate, but also through the holes in it.

Moreover, the annular section of the discharge plate in the area of the discharge opening is preferably made convex towards the discharge opening.

In addition, part of the stroke limiter of the discharge plate is made in the form of a piston located in the cavity of the cylinder communicated by the openings with the discharge chamber with the possibility of overlapping the holes with the piston when it is moved by the action of water hammer.

The invention is illustrated by drawings, where figure 1 shows a section of a valve; figure 2 shows a suction plate; figure 3 is a local section of the flow part of the valve according to G-D in figure 2 in a scale of 2: 1; figure 4 - injection plate; figure 5 is a local section of the flow part of the valve according to EE in figure 4 in a 2: 1 scale.

The self-acting combined valve comprises an annular suction plate 1 and a round discharge plate 2. A flow part of the suction part of the valve is formed in the seat 3. A sealing belt of the discharge part of the valve is formed in the center of the seat 3. The second sealing belt is located on the disk 4, assembled with a stroke limiter 5 for the discharge plate 2. The assembly of the disk 4 with the stroke limiter 5, carried out using the screw 6, is a device for unloading from hydraulic shocks. The position of the disk 4. in the assembly is changed by an adjusting washer 7 located between the stop 5 and the plate 2, since in this case an assembly gap is formed along the inner ring belt “A”, which reduces uneven edge wear during the running-in period. The location of the washer between the plate 2 and the disk 4 is unacceptable, since the tightness of the outer and inner annular belts in this case will be further deteriorated due to the characteristic uneven wear of the edges. In the upper part of the stroke limiter 5, a piston is made with the possibility of movement inside the cylinder made at the same time with the cover 8. The stroke of the stroke limiter 5 is pressed against the seat 3 by a buffer spring 9. Cavities of various pressures are sealed with gaskets 10.

The suction plate 1 is made with petals 11 arranged evenly in a circle, and spring (elastic) sections are formed between adjacent petals 11 (Fig. 2).

The discharge plate 2 has a circular shape and holes in the form of arcuate slots 12 (figure 4). The slots closest to the edge of the plate 2 are located along the edge of the disk 4, forming an injection hole with the seat 3.

The combined valve operates as follows. The suction part of the valve opens at the stage of the forward stroke of the compressor 13 from the dead center at the end of the internal expansion of the PT remaining in the dead volume. The filling of the compressor working chamber occurs when the pressure differential Δp of the elastically deformable petals 11 of the suction plate 1 is triggered, which, when bent, open the channels “B” of the seat 3. The movement of the petals 11 is limited by recesses 14 along the contour “B” of the compressor cylinder mirror, and then the passage section increases due to the spring sections of the slots between adjacent petals 11, providing an almost parallel position of the petals 11 with respect to the plane of the saddle 3 (see figure 3). In the initial position, the petals 11 of the plate 1 are returned under the action of their own elasticity. In the reverse stroke of the piston 13, the output of the RT through the discharge part of the valve occurs along the annular belts "D" (Fig. 4) of the seat 3 and disk 4 when the discharge plate 2 is lifted.

The plate 2 is made convex between the belts "D" and therefore has an annular protrusion of the size "Zh", which provides a reduction in hydraulic losses and additional alignment of the plate 2 in the flow of the working fluid. In addition, the moment of resistance of the radial section of the plate 2 increases, which reduces shear stresses and improves durability. Installation of the discharge plate 2 on the disk 4 is carried out using a washer 6 with a mounting gap along the inner annular zone "A", which reduces uneven wear of the edges during the running-in period.

When a water hammer occurs, the piston stops overlapping the stroke limiter 5 in the cylinder of the cover 8 and cuts off the enclosed space inside the cylinder of the cover 8, which is in nominal operation mode communicated with the valve discharge chamber. As a result of the piston moving inside the enclosed space with increasing pressure, damping occurs, the strokes of the travel stop 5 on the cover 8 are softened. This is because the increasing pressure inside the confined space counteracts the piston, reducing its speed and possible impact that occurs during wet running (buffer the analog spring in this case works with large shock loads.

Thus, the proposed configuration of the suction plate 1 provides an increased flow area, which improves the filling condition of the cylinder. The shape of the discharge plate 2 with a protrusion improves its dynamics and reduces stresses arising from collisions. The design also provides effective protection against water hammer. Moreover, in relation to analogues, the number of elements is reduced; the reliability and durability of the valve assembly are increased, including due to the installation of a discharge plate with a mounting gap, and in comparison with a US patent, an expanded bore section and effective protection against water hammer have been obtained.

Claims (4)

1. The combined valve for the piston stage of the compressor, containing a ring seat with at least one suction hole on the periphery and the discharge hole, an annular suction plate is installed between the cylinder of the piston stage and the seat, and the discharge element is connected with a travel stop, characterized in that that the suction plate is made with elastically deformable petals located along the ring with the formation between the petals of the spring sections with the possibility of overlapping the petals of the suction their holes. 2. The valve according to claim 1, characterized in that the injection hole has an annular shape and is formed by a seat and a disk connected to the stroke limiter, and the discharge element is made in the form of a round plate with at least one hole in the region of the edge of the disk. 3. The valve according to claim 2, characterized in that the annular portion of the discharge plate in the area of the discharge hole is convex towards the discharge hole. 4. The valve according to claim 1, characterized in that the part of the stroke limiter of the discharge plate is made in the form of a piston located in the cavity of the cylinder communicated by the openings with the discharge chamber with the possibility of overlapping the holes with the piston when it moves under the influence of water hammer.

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