JP5148287B2 - Valves, in particular compressor valves - Google Patents

Abstract

Valve, in particular for compressors, comprising a seat (1) provided with at least one flow way (111), an obturator member (4) able to obstruct said flow way (111) and movable with respect to said seat in a given direction, and means (5) for resiliently stressing said obturator (4), which are able to force said obturator (4) into a given position and are active in the direction of movement thereof; said resilient stressing means (5) comprise at least one cylindrical helical compression spring (5), characterized by the presence, between all the turns and along the entire working length of the spring (5), of inter-turn apertures.

Description

  The present invention relates to a valve, and more particularly to a reciprocating reciprocating compressor valve.

  A valve of the type currently used in the above compressor is a valve seat comprising a plate having a plurality of axial channels formed therein that may be concentric or non-concentric. It is usually an automatic valve, including a valve body called. The opening and closing of the flow path is performed by an obturator that is a member that may be composed of a plurality of elements or a single element. In all cases, the obturator is subjected to the action of an elastic pressing means, typically a metal cylindrical helical compression spring. This spring is housed in a valve body (called an “opposite valve seat”) consisting of a plate having a through-flow passage formed therein. The spring housing described above is preferably made of a thermoplastic material and the surface of the spring and external metal parts such as the wall of the housing formed on the counter valve seat or the obturator itself, for example. A spring protection element may also be included that functions to eliminate metal contact between the two.

  Most of the above springs are of the compression type with cylindrical or conical windings. The springs made of steel wire are formed with a total number of turns equal to the sum of the effective and non-effective turns. The non-effective turns are in contact with adjacent turns, and the turns are properly ground at both ends to ensure good axial stability of the spring.

This spring constitutes one of the most dangerous parts of the valve, and in fact the high open / close frequency causes various properties and varying degrees of wear on itself and the parts in contact therewith. According to the state of the art, most of the above wear caused by spring movement has been analyzed and defined and may be classified as follows.
A) Wear between the outer surface of the spring and the surface of the housing cavity, this wear being eliminated by the introduction of a plastic element inserted between the spring and the housing.
B) Wear between the proximal end of the spring and the housing cavity support surface, this wear being eliminated by the introduction of plastic elements.
C) Wear between the tip of the spring and the surface of the contact to the obturator, which wear is eliminated by the introduction of a plastic element or by the introduction of a plastic obturator.

  Despite these improvements, the spring continues to be one of the most dangerous parts of the valve and the cause of failure. Increasingly faster compressor development and constant efforts to eliminate oil in the compressed gas have increased the reliability problems of the above components.

  Therefore, the object of the present invention is for compressors, which have optimized spring wear characteristics compared to compressor valves known in the state of the art, ensuring a longer operating life of the compressor. It is to provide a valve.

  Accordingly, the present invention provides a valve seat having at least one flow path, an obturator member capable of closing the flow path and moving in a predetermined direction with respect to the valve seat, and elastically disposing the obturator. And a means for pushing the obturator to a predetermined position and operating in a direction of movement of the obturator, the elastic pushing means comprising at least one cylindrical helical compression spring. In particular, it relates to a valve for a compressor, characterized by the presence of a winding gap between all turns of the spring and along the entire working length.

According to a further feature of the valve according to the invention, the cylindrical helical compression spring has a winding gap between all turns and over the entire working length, Preferably, the difference in diameter between the end turns and the immediately adjacent turns is at least about 1.5 times and twice the cross section of the metal wire forming the spring. . The pitch of the springs can be variable.

  In a preferred embodiment, the dimensions of both end turns are smaller than the dimensions of the immediately adjacent turns. The valve according to the invention preferably comprises a protective member, preferably made of a plastic material and arranged in a housing containing the spring to further protect the spring from wear. It is.

  Further advantages and unique features of the device according to the invention will become apparent from the following description of an embodiment of this device which is provided only as a non-limiting example and with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a valve according to the invention, comprising a plurality of axially and eccentric through holes 111 functioning as a fluid flow path and engaging a threaded end 306 of a bolt 6. 1 designates the valve seat of the above valve, which includes a plate 101 having a mating central axial threaded through hole 201. A groove 121 communicating with the through hole 111 is also formed in the plate 101. The central part of the bolt 6 also has a bush 406 attached to it and a counter valve seat 2 with a central axial passage hole 302, the valve seat 1, the bush 406 and the counter valve seat. 2 are secured together by a nut 106 which is screwed to the threaded end 206 of the bolt 6. A duct 102 is formed in the counter valve seat 2 in the axial direction.

  The obturator 4 is disposed between the valve seat 1 and the counter valve seat 2, is coaxial and concentric with the bush 406, and can slide in the axial direction along the bush 406 by the central shaft hole 304 of the obturator. It is. The obturator is formed with eccentric openings 104 that are offset in the axial direction with respect to the shaft hole 111 of the plate 101 of the valve seat 1. These eccentric openings are formed in the duct 102 formed in the counter valve seat 2. Are aligned with. The valve seat 1 and the counter valve seat 2 are inserted into the blind hole 301 formed in the plate 101 and penetrate the hole 204 of the obturator 4 and enter the stop hole 202 of the counter valve seat. Are further coupled to each other.

  The counter valve seat 2 also includes a cylindrical housing 402 having a cylindrical helical compression spring 5 disposed therein, and the diameter of the end turn 105 is greater than the diameter of the turn 205 immediately adjacent thereto. small. The inserts 412 and 422 are disposed in the housing 402, and these inserts are preferably made of a thermoplastic material or the like, and have a function of eliminating metal contact between the spring 5 and the related housing 402. Yes. As a result of the action of the fluid flow through the hole 111 of the plate 101 of the valve seat 1, the end wall of the insert 412 pushes against the surface of the obturator 4, which is shown open in the figure, due to the action of the spring 5. . The spring 5 in this figure is shown in a compressed state within the housing 402.

  FIG. 2 shows a cross-sectional detail of the valve according to FIG. In FIG. 2, this valve is shown in the closed state by the obturator 4 in contact with the groove 111 of the plate 101 communicating with the hole 111 through which the fluid flows as apparent in FIG. The spring 5 is shown in this FIG. 2 in an equilibrium state which is enlarged compared to the state shown in FIG.

  FIG. 3 shows a plan view of the spring 5 acting on the valve obturator 4 and, as can be seen, the diameter of the end turn 105 visible in the figure is smaller than the diameter of the adjacent turn 205. . On the other hand, FIGS. 4A and 4B show that the presence of the winding gap is coupled with the difference in diameter between the open conical end winding 105 and the immediately adjacent winding 205, all over the effective operating section. Emphasizes the fact that winding causes non-interference.

  The principle of operation of the valve according to the invention will become apparent from the following description. A valve of the type shown in FIG. 1 is typically used in a compressor and operates at a significantly higher open and closed frequency. As a result, the elastic pressing means acting on the obturator 4 are considerably worn, which adversely affects the proper operation of the valve, which cannot be dealt with. The feature of the spring 5 is to ensure that it breaks to a much lesser extent than a normal cylindrical helical spring. One of the main causes of spring wear in question is that the above end turns are parallel to each other and perpendicular to the axis of the spring, but there are spreading planes of the windings, ie other turns of the spring Associated with the fact that it lies in a plane that is inclined with respect to the plane to be This different slope actually creates an inadequate distribution of the spring load and makes the spring susceptible to wear.

  In this case, this wear effect is greatly reduced and almost completely due to the presence between the winding gaps and the reduced diameter compared to the immediately adjacent winding of the end winding 105 described above. Even excluded. As can be seen from FIGS. 4A and 4B, the characteristics of this spring, namely the presence between the winding gaps and the difference in diameter between the end turns, are fully effective during compression of the spring. Ensure that there is no interference between all turns over the section (see FIG. 4B), so that the windings of this spring are less likely to wear and this spring is closest to the initial configuration And its operating life is significantly improved.

  Advantageously, by inserting the thermoplastic inserts 412, 422 into the housing 402, metal contact between the spring 5 and the wall of the counter valve seat 2 and / or the obturator 4 is further eliminated.

  A valve designed in this way can ensure correct operation on the one hand even at high frequencies and, on the other hand, that the elastic pressing means and thus the average life of the valve itself is considerably extended.

1 is a cross-sectional view of an embodiment of a valve according to the present invention. 2 shows a cross-sectional detail of the valve according to FIG. 1 in another operating configuration. FIG. 2 is a plan view of a spring used in a valve according to the present invention. It is sectional drawing of the spring in a resting state. It is sectional drawing of the spring in a compression state.

Claims (3)

A valve seat (1) comprising at least one flow path (111), and an obturator member (4) capable of closing the flow path (111) and moving in a predetermined direction relative to the valve seat; Means (5) for elastically pressing the obturator (4), which can push the obturator (4) to a predetermined position and operate in the direction of movement of the obturator. In the reciprocating compressor valve, the elastic pressing means (5) includes at least one helical compression spring (5).
In both the resting state and the compressed state, when the spring is viewed from the direction between all the turns of the spring (5) and perpendicular to the direction of expansion and contraction of the spring, Characterized by the presence of winding gaps visible along the working length,
Further characterized in that both end turns (105) of the spring (5) are smaller than the diameter of the turns (205) immediately adjacent to these end turns;
The difference in diameter between both end turns (105) of the spring (5) and the immediately adjacent turn (205) is at least 1.5 times the cross section of the metal wire forming the spring. A valve further characterized by a taper ratio change of both said end turns to be.   The diameter difference between the end turns (105) and the turns (205) immediately adjacent thereto is twice the cross section of the metal wire forming the spring. The valve described.   The valve according to claim 1 or 2, wherein the end winding formed in a conical shape is ground.

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