US3508849A - Compressor valve - Google Patents

Description

April 28, 1970 P. R. WEBER COMPRESSOR VALVE 3 Sheets-Sheet 1 Filed Jan. 30, 1968 R W MR E B CL w on L U A P ciim'vz ATTORNEY April 28, 1970 P. R. WEBER COMPRESSOR VALVE 3 Sheets-Sheet 2 Filed Jan. 30, 1968 FIG.

INVENTOR PAUL R. WEBER ATTORNEY April 28, 1970 P. R. WEBER 3,

COMPRESSOR VALVE Filed Jan. 30, 1968 5 Sheets-Sheet 5 F l G. 9 F I G. 10

F l G. 12

INVENT OR PAUL R. WEBER ATTORNEY United States Patent 3,508,849 COMPRESSOR VALVE Paul R. Weber, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Jan. 30, 1968, Ser. No. 701,682 Int. Cl. F04b 39/10 U.S. Cl. 417454 Claims ABSTRACT OF THE DISCLOSURE A suction-discharge valve for a high pressure compressor is provided, the valve comprising forward, intermediate and rearward sections arranged in contiguous series within acavity communicating with a compression chamber of the compressor. The intermediate section has an annular array of inlet passages running lengthwise of the cavity and also an annular array of diverging outlet passages encompassing the inlet passages, with the forward and rearward surfaces of the intermediate section serving as the valve seat for washer-like closure elements operating to open and close the inlet passages and outlet passages, respectively, in response to the action of the compressor. The forward section has an annular array of passages running lengthwise of the cavity communicating between the inlet and outlet passages of the intermediate section and the compression chamber of the compressor. The rearward, intermediate and forward sections are spaced from the wall of the cavity and appropriately sealed thereagainst to provide a chamber of the fluid compressed by the compressor surrounding the forward and intermediate sections and another chamber for surrounding the rearward section with the pressure of the inlet fluid. The rearward section has passages communicating the inlet fluid with the inlet passages of the intermediate section. The compressor has a discharge passage for discharging the compressed fluid from the first mentioned surrounding chamber and an inlet passage for supplying fluid to be compressed to the second mentioned surrounding chamber.

This invention relates to a suction-discharge valve for a high pressure fluid compressor.

In the use of a valve to first supply fluid of a relatively low pressure to a compressor and then to discharge the compressed fluid of relatively high pressure from the compressor, the valve is subjected to severe tensile stresses resulting from the cycling between low pressure fluid and high pressure fluid. This repetition of tensile stress eventually results in failure of the valve by fatigue. The compressor valves disclosed in U.S. Reissue Patent No. 25,899 to Waibel and U.S. Patent No. 3,106,169 to Prosser et al. are attempts to overcome this problem. Further improvement in valve life, however, is desirable.

The present invention provides a suction-discharge valve for high pressure service in a compressor which is believed to have a longer life than any valve available heretofore for such service. The valve comprises a valve body composed of a plurality of sections, forward, intermediate and rearward, positioned contiguously in series along the length of a cavity which communicates with the compression chamber of a compressor, with the forward section being closest to this compression chamber. Each of these valve sections of the valve body has at least one inlet passage for fluid to be compressed. Only the forward and intermediate valve sections, however, contain at least one outlet passage for the fluid that is compressed by the compressor. Each of the valve sections is spaced from the wall of the cavity. Sealing means are provided to divide the resultant space into a high pressure ice chamber laterally surrounding the portion of the valve body closest to the compression chamber, generally the chamber laterally surrounding the intermediate and forward valve sections, and a low pressure chamber laterally surrounding the remainder of the valve body. The outlet opening of the outlet passage opens into the high pressure chamber to thereby maintain the corresponding portion of the valve body under the high pressure of the compressed fluid. The inlet passage receives the fluid to be compressed from the low pressure chamber. A first valve closure is provided within the valve body for the inlet passage, and a second valve closure is provided for the outlet passage at the opening communicating with the high pressure chamber, these valve closures being responsive, i.e., opening and closing, to the operation of the compressor.

The invention will be discussed more fully hereinafter with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section of one embodiment of valve of this invention;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a section taken along line 33 of FIG. 1;

FIG. 4 is a section taken along line 44 of FIG. 1;

FIG. 5 is a section taken along line 55 of FIG. 1;

FIG. 6 is an enlarged cross-section of a portion of the inlet passage closure section of the valve, illustrating another embodiment for opening and closing inlet passages of the valve;

FIG. 7 shows in enlarged cross-section a portion of the outlet passage closure section of the valve, showing another embodiment for opening and closing such outlets;

FIG. 8 shows a portion of the outer face of the sealing ring in the direction of the line 8-8 of FIG. 7;

FIG. 9 shows in enlarged cross-section a portion of the outlet closure section of the valve, showing another embodiment of sealing ring for use in the present invention;

FIG. 10 shows in enlarged cross-section a portion of the upper sealing ring section of the valve, showing another embodiment forming a seal between the rearward section of the valve and the side wall of the cavity;

FIG. 11 shows in enlarged cross-section a portion of the outlet passage closure section of the valve, showing still another embodiment for forming a seal with the side wall of the cavity in this region of the valve; and

FIG. 12 shows in enlarged cross-section a portion of the upper sealing ring section of the valve, showing still another embodiment for forming a seal with the side wall of the cavity in this region of the valve.

FIG. 1 shows the head structure of a high pressure compressor 2, which defines a longitudinal bore 4 forming a compression chamber 6 wherein a piston 8 longitudinally reciprocates in conventional fashion. The head structure extends beyond the compression chamber 6 to define a cavity 10 which is elongated in the direction of the bore 4 and communicates therewith at one end and which is capped at the opposite end by an end flange 12 bolted to the structure by bolts 14. The head structure is shown to be unitary, but can be sectioned in any way desired for construction and use purposes.

Positioned within the cavity 10 is valve 20 of the present invention made up of a forward section 22, an intermediate section 24 and a rearward section 26 arranged in a contiguous series and forming the body of the valve, with the forward section 22 being closest to the compression chamber 6. These sections, preferably circular in transverse cross section and are held in place by pressure of the end flange 12 squeezing the valve 20 against the bottom wall 28 of cavity 10.

The sections are unitized, i.e., the entire valve 20 can be inserted and withdrawn from cavity 10 as a unit, by a connecting stud 30, which is in threaded engagement with the rearward section 26 and the intermediate section 24 and by peripheral spring 32 clamped over adjoining projections of intermediate section 24 and forward section 22, as shown in FIG. 1.

The diameters of sections 26, 24 and 22 decrease progressively in the order named, by each section having stepped diameters, as shown in FIG. 1. This facilitates installation and removal of the valve from cavity 10.

The forward section 22 has as in the embodiment shown a plurality of passages 34 running lengthwise of the cavity 10 and terminating at one end in communication with the compression chamber 6 and at their opposite ends in a hollow 36. There are eight passages 34 in an annular array as shown in FIG. 2.

Intermediate section 24 has a plurality of passages 40 running lengthwise of the cavity 10 and a plurality of passages 42 which diverge from the lengthwise direction of the cavity, as shown in FIG. 1. As shown in FIG. 3, both the passages 40 and 42 are in an annular array with the array of passages 42 encompassing the passages 40 and being oflset therefrom and with there being eight passages in each annular array. The passages 40 and 42 each communicate at one end with the hollow 36 in forward section 22. The opposite ends of passages 42 communicate with cavity 10. The opposite end of passages 40 communicate with an annular passage 44, which encompasses the connecting stud 30, in the rearward section 26.

The rearward section 26 also has a plurality of radially extending passages 46 communicating between the aunular passage 44 and cavity 10.

The structure defining the head portion of compressor 2 has an inlet passage 48 for fluid to be compressed and a discharge passage 50 for fluid that has been compressed by the piston 8 of the compressor.

As shown in FIG. 1, the lateral sides of the sections 22, 24 and 26 are spaced from the side wall 52 of the cavity 10. The resultant space between the surfaces is bottom sealed by an O-ring 54 compressed between opposing surfaces, lapped where in contact, of the forward section 22 and the bottom wall 28 of the cavity. The space is top sealed by an annular sealing ring 56 containing an O-ring 58 for sealing against a shoulder 60 of the rearward section 26, and an O-ring 62 for sealing against an annular boss 64 in the side wall 52 of cavity 10.

An additional annular sealing ring 70 is provided for dividing the space between the lateral sides of the sections 22, 24 and 26 and side wall 52 of the cavity into two separate pressure chambers. This is accomplished by O-ring 72 sealing against shoulder 74 of the rearward section 26, and by O-ring 76 sealing against an annular boss 78 in the side wall 52 of the cavity. The upper pres sure chamber 80 is of relatively low pressure, while the lower pressure chamber 82 is under relatively high preseach of these chambers urges their respective sealing sure as will be hereinafter explained. The pressure in rings 56 and 70 against their respective shoulders, achieving both metal to metal and O-ring seals. The inner ciroumferential surfaces of the sealing rings 56 and 70 are spaced from the side of section 26 so that fluid pressure can enter therebetween and urge the sealing rings against their respective annular bosses of the cavity, achieving both metal-to-metal and O-ring seals. The deformation of the sealing rings and O-rings to accomplish these seals is elastic, rather than plastic, to enable easy removal of the valve from the cavity when desired.

Opening and closing of passages 40 and 42 is accomplished by closure elements 84 and 86, respectively, as best shown in FIG. 1, which are both washer-like in appearance, as shown in FIGS. 3 and 4, respectively. The washer element 84 covers the openings of each of the passages 40 at the forward surface 88 of the intermediate section 24, which thereby serves as a valve seat for this washer element. The washer element 86 covers all of the openings of passages 42 at the rearward surface 90 of the intermediate section 24, to thereby serve as a valve seat for this washer element.

Washer element 84 is biased against surface 88 by springs 92 of equal circumferential spacing about the element 84 and positioned within retaining wells in the forward section 22. In this embodiment four springs 92 are used.

A similar biasing arrangement is used for the washer element 86, obtained by springs 94 positioned within retaining wells in the sealing ring 70. Eight equally spaced springs 94 are used, one positioned over each opening of a passage 42 in the surface 90.

The washer element is guided to and away from surface 88 by a raised section 100 within the hollow 36 of section 22. Similarly, the washer element 86 is guided to and away from surface 90 by a reduced diameter portion 102 of section 26. The bottom surfaces of hollow 36 and sealing ring each form a stop to limit the opening travel of the washer elements 84 and 86, respectively. In FIG. 1, washer element 84 is in the closed position and washer element 86 is about half-way in the open position.

In operation, on the intake stroke of the piston 8, fluid is sucked into the inlet passage 48 and then into the chamber of relatively low fluid pressure, followed by transit through the following passages in sequence, passages 46, 44, 40, hollow 36 and passages 34, into the compression cylinder 6, these passages thereby serving as the inlet passages. The suction provided by the intake stroke of the piston 8 causes the washer element 84 to move away from the surface 88, thereby opening up the communication of passages 40 with the hollow 36, and at the same time causes Washer element 86 to move against the surface 90, thereby closing passages 42. The subsequent compression stroke of piston 8 compresses the fluid within the compression chamber 6 and forces the compressed fluid through the passages 34, the hollow 36 and the passages 42 to overcome the biasing pressure of springs 94 on washer element 86, thereby causing the washer element to move away from the surface 90. The compressed fluid then passes directly into the chamber 82 which now has the relatively high pressure of the compressed gas, and this compressed fluid is discharged through passage 50. Accompanying the compression stroke of the piston 8 is the absence of suction pressure which had initially moved the washer element 84 away from the surface 88, whereby the springs 92 move the washer element 84 back into contact with the surface 88, thereby closing the inlet passages 40.

By way of example, the fluid sucked through passage 48 can be a monomer gas at 6,000 p.s.i. and the compressed gas discharged through passage 50 can be at a steady state pressure of 32,000 p.s.i. Thus, the rearward section is under a steady state external pressure from chamber 80 of 6,000 p.s.i., except for the forward portion or reduced diameter section 102, which is under the steady state pressure of the compressed monomer gas, namely, 32,000 p.s.i. In the intermediate section 24, passages 40' have a constant pressure of 6,000 p.s.i. while passages 42 are subjected to cyclical pressures, i.e., 6,000 p.s.i. during the suction stroke and 32,000 p.s.i. during the discharge stroke. The intermediate section 24, however, is under a steady state external fluid pressure of 32,000 p.s.i. from the compressed monomer gas in chamber 82. The forward section 22 is subjected to the same cyclical pressure conditions through the common passages 34, but is also subjected to the steady state pressure of the compressed gas in cavity 82. These steady state pressures are obtained in conventional fashion, e.g., by using a booster compressor with a 6,000 p.s.i. control outlet valve for supplying the gas through passage 48 and by using monomer processing equipment, e.g., a polymerization reactor, which includes a 32,000 p.s.i. pressure control valve, for receiving the gas from passage 50. The steady state fluid pressure acting on the exterior surfaces of sections 24 and 22, substantially maintains the sections under compression, despite the cyclical pressure conditions occurring in their passages, thereby greatly minimizing tensile stresses and fatigue failure.

Section 24 forms the valve seat for both the inlet closure (washer element 84) and outlet closure (washer element 86). The use of the washer elements 84 and 86 coupled with the surfaces 88 and 90 being continuous between openings of the passages 40 and 42 provides large bearing surfaces for the elements 84 and 86, which minimizes bearing stresses on the washer elements as well as stress concentrations in section 24 at the openings of passages 40 and 42 cooperating with the washer elements. These continuous surfaces between passage openings also provide a maximum cushioning effect for their respective washer elements. These factors contribute to the long life of the valve of this invention.

The outlet openings of the outlet passages in surface 90 marks the end of the passage of fluid of high compression through the valve. Once this fluid leaves these openings it is no longer restricted in movement by divided paths, but instead has 360 freedom of movement. This direct exposure of the openings of passages 42 and washer element 86 to chamber 82 and the attendant high clearance volume for the fluid minimizes fouling with dirt that may be present or solid polymer which may form during compression. Another advantage leading to long valve life is the absence of any sharp angles in the passages (34 and 42) within the valve structure through which the com pressed fluid must pass, which would lead to stress concentrations. In addition, the passages 34 and 42 represent a minimum volume of fluid within the valve subjecting it to pulsating pressure.

The valve 20 fits universally within the cavity 10, i.e., the valve does not have to be oriented in any way upon its insertion into the cavity, since the passages 48 and 50 communicate with their respective chambers regardless of its radial orientation. This invention also has the advantage of enabling the valve to be removed from the cavity, by removal of end flange 1-2, without disturbing the pressure couplings with the source of fluid to be compressed and with the apparatus using the compressed fluid vented through passage 50.

In another embodiment of the present invention the operation of the washer element 84 can be made springless in the manner such as shown in FIG. 6, wherein the passages 34 in forward section 22 are positioned such that they overlie the washer element 84, thereby exposing it directly to the path of compressed fluid formed on the compression stroke of the piston 8. This direct exposure causes the compressed fluid to impinge on the surface 110 of the washer element, thereby forcing it against the surface 88 thereby closing the input passages 40. In this embodiment, the opening of the washer element 84 occurs in the same way as the first described embodiment, namely, by suction pressure on the intake stroke of the piston 8, except that no biasing pressure of springs needs to be overcome. The hollow 36 is provided with an inner annular shoulder 112 which forms a stop to limit the opening travel of the washer element 84.

Operation of the washer element 86 can similarly be made springless, such as in the manner shown in FIG. 7, wherein the sealing ring is provided with a downwardly extending flange 114, the inner surface 116 of which forms a guide surface for the opening and closing of the washer element 86. As before, the bottom surface 118 of the sealing ring 70 forms a stop for the opening travel of the washer element 86. In FIG. 7, the washer element 86 is shown in the closed position, which is achieved by suction pressure on the intake stroke of the piston 8. Upon the compression stroke of the piston 8, impingement of the compressed fluid on the washer element 86 causes it to open against the surface 118, thereby opening the outlet passages 42. The compressed fluid exiting the passages 42 reaches the chamber 82 primarily by passing through the annular opening 120 in the washer element and then through holes 122 (see FIG. 8) in the flange 114 of the sealing ring, which forms circular grooves in the surface 118 of the sealing ring, communicating with the chamber 82. The reduced diameter portion 102 of section 26 is further reduced in diameter in the region of travel of the washer element 86 so as to increase the clearance volume of the compressed fluid exiting from outlet passages 42.

In another embodiment of the present invention, as shown in FIG. 9, the O-ring 72 is omitted from the sealing ring 70 of either FIG. 1 or FIG. 7 and a metal-tometal seal is achieved instead by lapping of the surface forming shoulder 74 and the upper surface 124 of the sealing ring 70. In another embodiment (FIG. 10) the O-ring 58 is omitted from the sealing ring 56 and metal-to-metal scaling is similarly obtained. In this embodiment, the sealing ring 56 is held in place by a spring 126 encircling the rearward section and positioned in a groove therein to form a shelf for the sealing ring.

In still another embodiment of this invention, the sealing ring is made integral with the valve section. For example, as shown in FIG. 11, the sealing ring 70 is replaced by an integral, somewhat flexible downwardly extending flange 130. Provision of a space 132 behind the flange enables compressed fluid to force the flange 130 into metal to metal contact With the annular boss 78 in the wall of the cavity. In this embodiment, the retaining wells for springs 94 are formed in the section 26. The sealing ring 56 can similarly be replaced as shown in FIG. 12, by an integral, somewhat flexible downwardly extending flange 134 forming both metal to metal and an O-ring seal with the annular boss 64 in the wall of the cavity.

Since the valves of the present invention will generally be used to compress gas to at least 6 of its original volume and usually at least thereof to produce gas compressed to at least 25,000 p.s.i., the materials of which the valve is made should be of high strength metals, typically high strength low alloy steel. The sealing rings are made of aluminum bronze to provide low modulus of elasticity yet high strength to these elements of the valve.

As many apparently wide different embodiments of this invention may be made Without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

What is claimed is:

1. A suction-discharge valve arrangement for a high pressure compressor having a fluid compression chamber, comprising structure defining a cavity communicating at one end with said compression chamber, a valve body positioned within said cavity, an end flange removably mounted to said structure at the opposite end of said cavity for clamping said valve body against said one end of said cavity, said valve body being spaced from the side wall of said cavity, sealing means dividing the resultant space between said valve body and said side wall into a high pressure chamber surrounding a portion of said valve body closest to said compression chamber and a low pressure chamber surrounding the remaining portion of said valve body, said structure having an inlet passage for supplying under a steady state pressure fluid to be compressed to said low pressure chamber and a discharge passage for discharging compressed fluid under a steady state pressure from said high pressure chamber, said valve body having at least one inlet passage communicating between said low pressure chamber and said compression chamber for supplying said fluid to be compressed thereto and at least one outlet passage terminating in an opening which is exposed to said high pressure chamber and communicating with said compression chamber for supplying the fluid compressed therewithin to said high pressure chamber, first closure means within said valve body responsive to the intake and compression of the fluid supplied in said compression chamber to open and close, respectively, said inlet passage in said valve body, and second closure means operating at said opening responsive to the intake and compression of the fluid supplied in said compression chamber to close and open, respectively, said outlet passage in said valve body.

2. The suction-discharge valve arrangement of claim 1 wherein said valve body includes a series of valve sections, forward, intermediate, and rearward, positioned contiguously within said cavity, the forward section being closest to said compression chamber, with said inlet passage in said valve body being present in each said valve sectons and said outlet passage being present in said intermediate valve section and in said forward valve section.

3. The suction discharge valve arrangement of claim 2, wherein said opening in said outlet passage is in the rearward surface of said intermediate section and said sealing means includes a seal between the forward portion of said rearward valve section and the sidewall of said cavity.

4. The suction-discharge valve arrangement of claim 3 wherein a plurality of said outlet passages are present in said intermediate valve section in an annular array diverging towards their respective openings and said second closure means includes a washer element operating at all said openings.

5. The suction-discharge valve arrangement of claim 4 wherein a plurality of said inlet passages in said valve body are present in said intermediate valve section in an annular array encompassed by the annular array of said outlet passages therein and said first closure means includes a washer element for closing all said inlet passages.

6. The suction-discharge valve arrangement of claim 5 wherein said first closure means operates against the forward surface of said intermediate section to obtain said closing of all said inlet passages.

7. The suction-discharge valve arrangement of claim 6 said forward and rearward surfaces of said intermediate valve section are solid except for openings of said plurality of inlet passages and outlet passages thereinto.

8. The suction-discharge valve arrangement of claim 6 wherein said first closure means is exposed to said compression chamber so as to be closed by the compression of fluid therein.

9. The suction-discharge valve arrangement of claim 2 wherein said inlet passage and said outlet passage in said forward valve section are common.

10. The suction-discharge valve arrangement of claim 2 wherein said inlet passage in said rearward valve section includes longitudinal passage and a plurality of passages extending radially therefrom to communicate with said low pressure chamber.

References Cited UNITED STATES PATENTS 2,957,620 10/ 1960 Turnwald 230-231 3,309,013 3/1967 Bauer 230-2331 ROBERT M. WALKER, Primary Examiner US. Cl. X.R.

l37516.l3; 4l7564, 5-69

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