GB2158558A - High pressure valve having liner wear indicator - Google Patents

Abstract

A durable wear liner 54 is disposed downstream of the plug closure 48 and is spaced from and sealed (66, 74) within the body 12 to define a closed chamber 82 surrounding the liner. To give an indication in the event of failure of the liner resulting in fluid breaching the liner and entering the chamber 82 to wear upon the valve body, a wear indicator is provided. The wear indicator includes a cylinder (108) which communicates with the closed chamber 82 surrounding the liner 54 and slidably houses a piston 110. Upon failure of the liner, fluid enters and pressurizes the chamber 82 and cylinder (108) to displace the piston 110 to signify liner failure. A vent means (126) is provided in the cylinder to vent small quantities of fluid. Accordingly, expansion of the fluid or small leaks of fluid into the chamber not indicative of liner failure are vented to prevent the wear indicator from giving a false indication of wear. <IMAGE>

Description

SPECIFICATION High pressure valve having liner wear indicator This invention relates to high pressure valves. More particularly it relates to wear liners for high pressure valves and devices for indicating wear of such liners.

It has been known in the prior art that valves, and particularly valves disposed in high pressure lines, are subject to wear. In most cases wear tends to concentrate downstream of the valve plug. Throttling of fluid flow through the valve by positioning a plug relative to a seat creates turbulence and high, sometimes even sonic, velocities for a distance downstream of the plug until flow conditions stabilize. It is believed that the turbulence and velocity of the fluid downstream of the plug contributes significantly to wear. Where the fluid is abrasive, corrosive or mixed phase, wear tends to progress at an accelerated rate.

Given sufficient time, these high pressure fluids can wear through the valve body causing the fluid to leak to the environment. Leakage of the high pressure fluid necessarily alters the flow of fluid through the valve, which in turn, may affect downstream processes. Perhaps more importantly, the leakage of fluid may be damaging to the environment or could otherwise present significant risks to surrounding personnel.

To resist wear and prolong the in-service life of the valve, it has been known to provide a wear sleeve downstream of the plug; the sleeve being made of material better adapted to resist wear than the typically cast or forged steel valve body. However, once the sleeve wears through, fluid comes in contact with and begins to erode the valve body to eventually leak therefrom. While inspection and replacement of the sleeves prior to their failure can prevent erosion of the valve body, constant inspection is costly from a labor standpoint. Accordingly, there is a need for a wear indicator which automatically signals when the fluid has worn through the sleeve.

There is, therefore, provided in the practice of the present invention a wear member and wear indicating means for a high pressure valve. The valve has a body with a fluid inlet and outlet and a passage to permit the fluid to flow from the inlet to the outlet through the valve body. Disposed in the valve to throttle fluid flow, is a plug manipulated between a closed position wherein the plug mates in a seat to block fluid flow, and a full open position where the plug is fully withdrawn from the seat. The wear member is disposed in the valve downstream of the plug and is spaced from and sealed within the body to define a closed chamber surrounding the wear member.The wear member is constructed from a durable material making it well adapted to accept and resist the wear induced by the flowing fluid which may be abrasive, corrosive, high pressure, mixed phase orthe like. Forthis purpose, the wear member or portions particularly subject to wear may be fashioned from, for example, tungsten carbide.

To give an indication in the event of failure of the wear member resulting in fluid breaching the wear member, entering the chamber and beginning to wear upon the valve body, the wear indicating means are provided. The wear indicating means include a cylinder which communicates with the closed chamber surrounding the wear member.

Disposed in the cylinder is a piston. Upon failure of the wear member, fluid enters and pressurizes the chamber and cylinder. In response to pressurization of the cylinder, the piston is displaced activating a visual indicator signifying that the wear member has failed. Additionally or alternatively, the piston may actuate an audible alarm or send a signal to a control panel.

To prevent the piston from being displaced as a result of a slow leak past a seal or the like and giving a false indication of wear, vent means are provided for the chamber. Preferably, the vent means are embodied as a conduit communicating at one end with the chamber and at the other end at a location in the cylinder to bypass the piston and vent the chamber to atmosphere. A restriction is included n the conduit so that until the wear member fails, small quantities of fluid will bypass the piston and flow into the atmosphere. Accordingly, the chamber is normally vented to atmosphere.

Should the wear member fail, the chamber is quickly flooded with fluid pressurizing the chamber.

The vent restriction chokes fluid flow and the chamber quickly pressurizes. Pressurization of the chamber results in displacement of the piston to block the conduit so that fluid cannot vent to the environment. Displacement of the piston also gives the indication of wear.

The high-pressure valve according to the above features has several advantages. The valve is relatively inexpensive to manufacture, while being well suited for high-pressure service or other services where wear is a factor. By virtue of the durable wear member, the body can be cast or machined from relatively inexpensive soft steel since it need not withstand fluid wear. When the wear member fails, it can be replaced by another providing wear protection for the valve body throughout its useful life.

Another advantage is that false indications of wear member failure are prevented. False indications are costly from a labor process standpoint in that the high-pressure valve would be prematurely removed from service.

Still another advantage of the high pressure valve according to the present invention is that failure of the wear member anywhere along its length will activate the wear indicator. The chamber surrounding the wear member provides an unobstructed passage for the fluid to communicate with and actuate the wear indicator means.

These and other features and advantages of the present invention will be appreciated as the same becomes better understood by reference to the following detailed description of the presently preferred embodiment when considered in connection with the accompanying drawings, wherein; Figure 1 is a side partial section view of the valve according to the present invention; Figure 2 is a side section view of the wear member for the valve of Figure 1; and Figure 3 is an enlarged side section view of a wear indicator for the valve.

Turning to the drawings, Figure 1 shows a highpressure valve 10 incorporating the features of the present invention. While the valve 10 is shown as being an angle needle-type valve, it is to be understood that other types of valves fall within the scope of the present invention. Furthermore, while the following description as hereinafter set forth is directed toward a valve for high-pressure gas service, it is by way of illustration and is not intended to limit the application of the valve to such service.

The valve 10 has a body 12 which may be cast steel or the like. Viewing Figure 1 from left to right, the body 12 includes a series of coaxial bores beginning with a countersink defining an outlet 16.

The outlet 16 terminates at a lesser diameter, intermediate bore 18 which extends into the valve body 12 to terminate at a larger diameter chamber bore 20. In turn, the chamber bore 20 opposite the intermediate bore 18 terminates at still a larger diameter plug bore 22. At the plug bore 22 the lesser diameter chamber bore 20 defines an annular lip 24, the purposes of which will hereinafter become evident.

The supply of high-pressure gas enters the valve body 12 at an inlet 26 positioned, as shown in Figure 1, at the side of the valve body 12. The inlet 26 is defined by a bore having substantially the same diameter as the outlet 16. Supply bore 27 extends from the inlet transversely to and intersecting the plug bore 22.

To connect the valve 10 to the pipeline an inlet flange 28 of well known construction it is secured to the valve body 12 at the inlet whereas an outlet flange 30 is secured to the body 12 at the outlet 16.

The outlet flange 30, for purposes which will hereinafter become evident, includes, viewing Figure 1 from left to right, support bore 36 having a diameter slightly less than that of the intermediate bore 18 in the valve body 12. The support bore 36 in turn terminates at a flange bore 38 having a diameter the same as and adapted to register with the outlet 16. As can be appreciated, the gas enters the valve body atthe inlet 26 and flows sequentially through the supply bore to the plug bore, and downstream through the chamber bore, intermediate bore, outlet, through the outlet flange and ultimately to downstream piping.

Secured at one end of the valve body 12 by a nut 40 is a valve bonnet 42. In a known fashion the bonnet 42 supports a stem 44 having at one end a hand wheel 46 and at the other end a suitable valve plug 48. Rotation of the hand wheel 46 by virtue of a threaded coupling (not shown) between the stem 44 and bonnet 42 results in axial displacement of the stem 44 and plug 48 between a closed position as shown in Figure 1, preventing fluid from flowing through the valve and an open position.

For purposes which will become evident, a spacer 50 is positioned within the plug bore 22. The spacer 50 is embodied as a hollow cylinder having an outer diameter to be spaced within the plug bore 22 and an axial length to terminate short of the shoulder 24 as shown in Figure 1. At one side, the spacer 50 has an opening 52 the same diameter as and adapted to register with supply bore 27to admit highpressure gas into the spacer 50.

During throttling of the gas flow in the valve 10 the velocity of the gas downstream of the plug 48 increases. If the gas has entrained abrasive particles such as sand, the high velocities tend to concentrate wear at a location at and just downstream of the plug. Unless otherwise resisted, the sand would eventually wear through the valve body 12 releasing the gas to the environment. The release of gas may release harmful products to the environment, present a fire hazard, or injure nearby personnel or equipment. Additionally, wearing away of the valve body 12 damages the valve to such an extent that it may have to be discarded and replaced.Over and above the aforesaid problems, permitting the sand to wear through the valve body and discharge to the atmosphere may present an immediate impact on downstream processes and could result in a longterm shut-down until a new valve is acquired and installed in place of the worn valve.

To prevent the sand from wearing upon the body valve 10 includes a cylindrical wear member 54 as shown in Figures 1 and 2. The wear member is disposed at and downstream of the plug 48 and consists of a carrier sleeve 56 which coaxially mounts a durable, wear resistant wear liner 58.

The carrier sleeve 56 includes a cylindrical trunk 60 having an outside diameter adapted to be closely received by the support bore 36. The trunk 60 terminates at one end 62 which is received and restrained by the support bore 36. To prevent fluid from leaking around the carrier sleeve 56 at the one end 62, a seal groove 64 is circumscribed thereabout to receive and mount a sealing O-ring 66. O-ring 66 may be supported within the seal groove 64 by a back-up ring 68. Opposite the one end 62 the carrier sleeve 56 includes a cylindrical head 70 adapted to be closely received within and supported by the plug bore 22. Again, to prevent fluid from leaking about the carrier sleeve 56, a seal groove 72 encircles the head 70 and receives an O-ring 74 and a back-up ring 76. The head 70 is spaced from the trunk 60 by an enlarged portion of the carrier sleeve defining a cylindrical neck 78.The neck 78 has an outside diameter greater than the trunk 60 but less than the head 70 to create an annular shoulder 80 therebetween. The shoulder 80 is adapted to abut the annular lip 24to prevent the member 54 from moving in a direction toward the outlet. The spacer 50 abuts the member head 70 to trap the head 70 against the lip 24.

To position the wear member 54 in the valve body, the bonnet 42 is removed via the nut 40 freeing the stem 44. The wear member 54 is thereafter inserted into the valve body followed by the spacer 50. The valve 10 is then reassembled.

As can be appreciated from the foregoing in viewing Figure 1, between the one end 62 and head 70, the carrier sleeve is somewhat spaced from the walls of the flange bore 38, outlet 16, intermediate bore 18, and chamber bore 20 to define a chamber 82 encircling the wear member 54. In that the carrier sleeve 56 is supported at the one end 62 by the support bore 36 and at the other end by the plug bore 22, should fluid breach the member 54 and flow into the chamber 82, such a breach will not radially displace the wear member 54 to alter the spaced relationship between the body and the wear member thereby preventing the fluid from communicating with all parts of the chamber 82.

To provide a durable surface to resist wear, the liner 58, which may be fashioned from tungsten carbide or the like, is coaxially received into the carrier sleeve 56. The liner 58 is cylindrical including a constant diameter portion defining a barrel 84 and a somewhat enlarged base 86. The base 86, in turn, terminates at still a larger diameter rim 90. Accordingly, as best shown in Figure 2 an annular face 88 is described between the boare 86 and the rim 90. The barrel 84 is adapted to extend substantially from the carrier sleeve one end 62 to a location intermediate of the neck 78 as shown in Figures 1 and 2. To receive the barrel 84 a suitable circumferential recess 89 is formed in the carrier sleeve 56 such that the internal diameter of the liner 58 smoothly registers with the diameter of the carrier sleeve 56 at the one end 62.The internal diameter of the liner 58 remains constant up to a location representing approximately the mid-point of the base 86. Upstream of this location, to the right in Figure 2, the internal diameter of the liner 58 enlarges in a conical fashion to define a control cone 96 adapted to closely mate with the plug 48. By virtue of the progressively larger diameter bore 86 and rim 90, the liner does not become overly thin at t'ne seat, thereby prolonging its in-service life. To closely receive the base 86 and rim 90 the carrier sleeve 56 includes a first counterbore 92 which extends from the recess 89 to a larger diameter second counterbore 94. The first and second counterbores cooperate to define an annular ledge 95 which abuts and supports the annular face 88 and the remainder of the wear liner.To interconnect the liner 58 and carrier sleeve 56, a shrink-fit, epoxy glue, or the like may be used.

In operation the plug 48 is received by the control cone 96 to provide for the on-off function of the valve and for throttling. As can be appreciated, in the off position as shown in Figure 1 gas is prevented from passing through the valve in that the plug 48 completely blocks gas flow through the control cone 96. Rotating the hand wheel to open the valve withdraws the plug from the seat to provide an increasingly larger annular flow passage around the plug. By virtue of the restriction of the control cone itself, and more particularly due to the flow passage created between the plug and the control cone, a pressure drop in the gas occurs through the throat.

This pressure drop is accompanied by an increase in velocity at and downstream of the seat. For highpressure gases, this increase in velocity may be to the sonic velocity of the particular gas. The increase in velocity causes solid particles entrained in the gas to wear upon the wear member 54 at and downstream of the throat 96. As can be appreciated, the wear member 54 with its durable liner 58 is adapted to resist such wear and protect the valve body 12.

When the valve 10 has been in service for a long period of time, the liner 58 and thereafter the carrier sleeve 56 will eventually wear through, permitting the gas to breach the member and enter the chamber 82. If left unnoticed, the gas at the point of breach, and at other points formed along the length of the wear member 54, will begin to wear upon the valve body damaging the body and eventually completely wearing through the body causing the gas to leak into the environment.

To provide an indication that the wear member 54 has been breached, the valve 10 according to the present invention also includes means for indicating wear of the member 54 embodied, as shown in Figure 1, as a wear indicator 98. The wear indicator 98 is connected to the valve body by a suitable fitting 100 and communicates with the chamber 82 via a conduit 102 in the valve body. As shown in Figures 1 and 3, the indicator 98 has a housing 104, one end of which is generally closed, having a threaded opening 105 to threadably receive the fitting 100, whereas the other end is open and includes threads to threadably receive a cap 106. Between the opening 105 and the cap 106 the housing 104 includes a pocket 107 and a chamber defining a cylinder 108 adapted to slidably receive a piston 110.The pocket 107 is interposed between the cylinder 108 and opening 105 and is of a lesser diameter than the cylinder to create an annular stop 116 the purpose of which will become evident. Through the conduit 102 and fitting 100 the chamber 82 communicates with the pocket 107 and the cylinder 108.

The piston 110 has a piston head 111 of a diameter to closely slide within the cylinder 108. Extending from the piston head is a shaft 112 adapted to be slidably received by an axial hole 118 in the cap 106.

The piston is normally urged to a position wherein the piston head abuts the stop 116 which limits the travel of the piston within the cylinder. For this purpose the cap has a spring bore 120 defining an annular ledge 121 to support one end of a spring 122, the other end of the spring engaging the piston head 111. As can be appreciated, displacement of the piston 110 against the bias of the spring 122 causes the piston shaft 117 to slide through the hole 118 and extend an indicator 123 affixed to the shaft outwardlyfrom the cap 106 to visually appear. For visibility, the indicator 123 may painted with a brilliant color such as red or orange. The cap 106 limits the travel of the piston in a direction away from the stop 116. To provide a sliding seal for the piston a suitable ring seal 124 is disposed to encircle the piston head 111.

From the foregoing, the operation of the valve 10 can be set forth. While in service the wear member 54 of the valve provides a durable insert to resist and accept wear caused by solids in the high-pressure gas. The material of the liner 58 is particularly adapted for this purpose. After a prolonged period of service, the member 54 may fail permitting the fluid to breach the wear member and enter the chamber 82 at a point somewhere along the length thereof. As the fluid breaches into the chamber 82 the chamber 82 becomes pressurized by such fluid pressurization ofthe chamber 82 in turn pressurizing the pocket 107 at the indicator 98 via the conduit 102 and fitting 100.

Pressurization of the pocket 107 urges the piston against the spring 122 causing the indicator 123 to be extended from the cap 106 giving a visual indication that the wear member 54 has failed. Of course it is to be understood that the piston 110 could also actuate an audible alarm or activate an electronic signal art a control panel or the like.

By virtue of the chamber 82 extending over substantially the entire length of the wear member 54, a breach at any location therealong is quickly transmitted to the indicator 98. Unlike prior art liners which are closely spaced within the valve body, the maintenance of the space relationship between the wear member 54 and the body 12 to define the chamber assures that the breaching gas can flow to and activate the indicator 98. Absent maintenance of such a spaced relationship may cause, upon breach of the fluid, displacement of the wear member to close the conduit 102 and prevent the gas from displacing the piston to indicate a wear member failure.

To prevent the indicator 98 from giving a false indication of failure of the wear member, vent means are provided at the indicator 98. The vent means, as shown in Figures 1 and 3, consists of a vent line 126 which bypasses the piston head. The vent line communicates at one end with the pocket 107 and at the other end with the cylinder 108 at the shaft side of the piston head. For ease of manufacture the vent line 126 may be fashioned from a series of first, second and third bores 128 through 130, which are capped off by suitable stoppers 132. To restrict flow through the vent line, the third bore 130 includes a restriction 131 substantially intermediate of the cylinder to limit the flow of gas through the vent line.

Should the gas in annular chamber 38 expand due to temperature changes or should a small leak of gas occur at the O-ri ngs 66 or 74 and the gas enter the chamber 82, the gas will pass through the conduit and fitting and thereafter through the vent line 126 around the piston head to the cylinder. From the cylinder the gas is vented to the atmosphere via an opening 132 located in the side of the housing.

Without such a vent line, a small leak about either of the O-rings would gradually pressurize the cylinder, displacing the piston 110 and giving a false indication that the wear member 54 has failed. Such a false indication would result in the premature removal of the valve 10 from service for replacement of the wear member 54, such removal resulting in unnecessary labor costs and, possibly, process shutdowns. According to the present invention, should indeed the wear member 54 fail and gas breach into the chamber, the flow of gas into the chamber 82 will result in pressurization of the chamber 82 at a rate above that at which the vent line can relieve the pressure through the restriction 131, resulting in displacement of the piston and the desired indication of wear member failure. Displacement of the piston closes the restriction 131 preventing inordinate quantities of gas from venting to the atmosphere.

While I have set forth certain embodiments of the present invention, it is to be understood that it is subject to modification without departing from the spirit and scope of the claims hereinafter set forth.

Claims (8)

1. Avalve having a body adapted to pass a fluid therethrough under pressure, a movable element disposed to control fluid flow, a valve line disposed in the body, the liner being spaced from and co-operating with the body to define a closed chamber between the liner and body, seal means for sealing the chamber from the fluid, and indicating means for indicating leak failure of the liner, the indicating means being responsive to invasion of the fluid into the chamber.

2. Avalve according to Claim 1, wherein the indicating means comprise a conduit communicating with the chamber, the conduit supplying fluid to an indicatorforsignalling leak failure.

3. Avalve according to Claim 1 or 2, wherein the indicating means comprise a piston disposed within a cylinder, pressurization of the chamber displacing the piston for signalling leakfailure.

4. A valve according to any of the preceding claims, including means for venting the chamber through a restriction to prevent a false indication of failure of the liner resulting from a gradual leak of the pressure fluid.

5. A valve according to any of the preceding claims, wherein the liner is of a durable material to resist fluid wear.

6. Avalve according to Claim 5, wherein the liner is of tungsten carbide, silicon carbide or similar hard material.

7. A valve according to Claim 1, wherein the indicating means comprise a housing having closed first and second ends and a closed cylinder between such ends, the cylinder communicating with the chamber through an opening in the first end, a piston having a piston head slidably and sealablydisposed in the chamber and a shaft extending therefrom to an opening in the housing second end, the piston being movable in response to fluid entering the chamber to extend the shaft through the second end to indicate fluid breach through the liner, means for biasing the piston to a position such that the shaft is withdrawn into the housing and a vent through the housing by-passing the piston head to normally vent small quantities of fluid from the chamber at the first end not indicative of fluid breach through the liner, wear failure of the liner pressurizing the chamber and cylinder beyond the capacity of the vent to displace the piston for an indication of wear, such displacement of the piston rendering the vent ineffective.

8. Avalve, substantially as described with reference to, or as shown in, the drawings.