GB2156492A - Tapered plug retracting slip valve - Google Patents

Abstract

A tapered plug retracting slip valve in which the usual lower extending trunnion (64) of the plug (50) is integrated into the bottom surface of the valve body (48) and extends upwardly through a matching aperture in the bottom of the plug (50). The result is an improved valve of reduced height, flat bottom and deletion of sediment trapping area and drain plug while still providing coaxial stabilization of the plug (50) during vertical and rotary motion for opening and closing of the valve. The through-hole into the valve passageway furthermore allows a flushing action by the media flowed. <IMAGE>

Description

SPECIFICATION Tapered plug retracting slip valve The present invention relates generally to valves and more particularly, to improved tapered plug retracting slip valves.

Plug-type valves are well-known in the prior art particularly in the oil and gas industries where their positive sealing and superior flow characteristics are highly advantageous for controlling the flow of such fluids. Plug-type valves are generally the type in which a valve body is provided with a pair of coaxial ports which are connected to incoming and outgoing fluid lines for movement of the fluid under pressure therethrough. Typically, a plug is adapted to selectively rotate within the main chamber of the valve to either provide a continuous channel between the incoming and outgoing coaxial ports when the valve is in the open position or to provide a fluid tight seal in one or both of the coaxial interconnecting ports when the valve is in the closed position.

An illustrative example of a plug-type valve in the prior art is disclosed in Patent No.

3,011,513 to Heinen which discloses a centrally located tapered plug disposed within the valve chamber and provided with an upwardly extending shaft or trunnion which extends through the upper portion of the valve body and a downwardly extending shaft or trunnion which is received and terminates within the bottom plate of the valve body. As is wellknown in the art, such trunnions assure the coaxial stability of the rotatable plug while also permitting vertical motion of the plug to allow seating and unseating of the valve slips as a result of the interaction of the tapered surface of the plug and the slips.

One drawback of the otherwise advantageous tapered plug of the prior art is the lower extending trunnion of the plug. More specifically, because of the lower extending trunnion the valve body overall height must be increased to provide a trunnion receptacle in the lower portion of the valve body. Typically, this receptacle requires that the lower portion of the valve body be extended thereby precluding the bottom of the valve from being flat and rendering the valve incapable of standing alone. Furthermore, this trunnion receptacle region provides an unwanted sediment trapping area within the valve as well as an area for trapping fluid which requires the use of a drain plug in the bottom of the valve coaxial with the trunnion in order to provide a means for draining the valve entirely such as for servicing.

The present invention seeks to provide means for overcoming the aforementioned disadvantages of the lower extending trunnion of the prior art tapered plug valve. More specifically, in the present invention the aforementioned disadvantages are overcome by utilizing an inverted trunnion configuration wherein the lower trunnion forms an integral portion of the valve body instead of the plug and wherein furthermore, the plug is modified to receive the inverted trunnion so that it may still provide the needed vertical and rotational motion to accomplish the opening and closing of the valve in the well-known manner for tapered plug retracting slip valves.

The present invention overcomes the aforementioned disadvantages of the prior art by providing a tapered plug retracting slip valve in which the usual lower extending trunnion of the plug has been instead integrated into the body or into the lower plate of the valve and has been reconfigured to protrude up into the lower portion of the plug which in turn has been modified to receive the inverted trunnion for the well-known purpose of maintaining axial stability during both rotary and vertical motion in opening and closing the valve. As a result of this novel improvement, the overall height of the valve may be reduced and the lower portion of the valve body may now be flat permitting the valve to be configured in a stand-alone configuration.Furthermore, a sediment trapping area of the valve may be omitted and the previously required drain plug often used to provide access to the sediment trapping area of the old configuration may also may be omitted. Finally, and perhaps most importantly, the manufacture of the valve is made easier because the outer diameter of the trunnion may now be machined concurrently with the machining of the inner diameter of the valve body.

Thus it will be seen that the present invention comprises a tapered plug retracting slip valve which utilizes a novel inverted trunnion configuration which serves the same purpose as a standard lower standing trunnion of a prior art similar valve but is in fact, a unitized part of the body or lower plate of the valve rather than part of the plug as has always been the case. Because the plug is raised in turn from the closed and seated position to the full open position, the inverted trunnion is designed to be flush with the lower waterway portion of the plug in the full open position so as not to interfere with the free fluid flow. In the closed seated position of the valve, the inverted trunnion will protrude into the waterway but because the valve is closed at this time there is of course, no problem resulting from the extension of the trunnion into the waterway.

It is therefore possible to provide an improved tapered plug retracting seal valve which utilizes a novel lower trunnion configuration for overcoming the aforementioned disadvantages of the prior art.

It is also possible to provide a tapered plug retracting seal valve in which the lower of the two trunnions normally integral to the valve plug for the purpose of providing coaxial stability to the plug during both vertical and rotary motion thereof, has instead been made a unitized component of the valve body and wherein the lower portion of the plug has been modified to provide a matching aperture for receiving the lower trunnion.

It is further possible to provide a tapered plug retracting seal valve which utilizes an inverted trunnion configuration thereby permitting a reduction in the overall height of the valve and omission of both a common prior art sediment trapping area as well as the preference for a drain plug in the bottom of the valve in prior art configurations.

It is further possible to provide a tapered plug retracting seal valve which utilizes an inverted lower trunnion, rendering the valve easier and less costly to manufacture as the outer diameter of the trunnion may be machined concurrently with the inner diameter of the body.

The invention will now be more particularly described with reference to the accompanying drawings, in which: Figure 1 is an abstract sectional view of a tapered plug retracting seal valve or the prior art; Figure 2 is a three dimensional cut-away view of one embodiment of a tapered plug retracting seal valve according to the present invention; Figures 3 and 4 are sectional views of the tapered plug retracting seal valve shown in Fig. 2 and illustrating the open and closed positions thereof, respectively.

Referring now to Fig. 1 there is shown a prior art tapered plug retracting seal valve 10 which is discussed herein for the purpose of illustrating the manner in which the plugs of such valves normally operate with conventional trunnions stabilizing coaxial motion in both vertical and rotary directions. More specifically, as shown in Fig. 1, the prior art valve 10 comprises an inlet 2, an outlet 14, an upper plate 1 6 and a lower plate 1 8 which form the valve body having an enclosed chamber 1 9. Located within chamber 1 9 are a plug 20, at least one slip 22 and a seal 23.

Plug 20 is tapered and slip 22 is wedgeshaped. As those having skill in the art to which the present invention pertains will understand, as a result of these respective shapes for plugs 20 and slip 22, when the valve is being opened from a fully closed position, the plug is first moved upwardly in a vertical direction thereby retracting slip 22 and thus reducing the pressure of seal 23 against the interior surface of inlet 1 2. At this point the plug is then rotated to align a waterway 28 with the inlet 1 2 and outlet 14 to permit flow through the valve.It will also be observed that in order to facilitate the combined vertical and rotational motion of plug 20, a pair of trunnions are provided, namely, an upper trunnion 24 and a lower trunnion 26 which extend out from the two ends of the plug into the upper plate 1 6 and lower plate 18, respectively.

As also seen in Fig. 1, lower plate 18 is specially shaped to accommodate lower trunnion 26 by providing a trunnion receptacle 30 which is provided to axially stabilize the lower trunnion while providing the opportunity for the lower trunnion to be moved in both vertical and rotational directions during opening and closing of the valve. It will be observed however that because of the necessity of the receptacle 30 to accommodate the lower trunnion extending from plug 20, lower plate 1 8 must be of relatively complex shape and of substantial height which increases the overall height of the valve 10 and further precludes the valve from having a flat bottom plate without also substantially increasing the cost and weight of the valve by increasing the mass of lower plate 18.Furthermore, it will be observed that receptacle 30 provides an inherent sediment trapping area which, with the passage of time, can readily become inimical to the operation of the valve. As a result, a drain hole is required in the lower central portion of lower plate 18 and also required is a drain plug 34 to provide a means of utilizing drain hole 32 for selectively draining the receptacle 30, thus adding additional maintenance steps as well as material and manufacturing costs to the valve.

Reference will now be made to Fig. 2 which illustrates an exemplary tapered plug valve incorporating the present invention. Tapered plug valve 40 is of the lever operated type which is disclosed in detail in copending patent application Serial No. 329,647 entitled "Lever Operator For Valve Control and Actuating Mechanism" filed December 11, 1981 and assigned to the assignee of the present invention. Valve 40 comprises an inlet 42, an outlet 44, an upper plate 46, valve body 48, and a plug 50. Plug 50 includes a waterway 52 through which the fluid flows when the valve is in the open position. The plug also comprises an upper trunnion 54 which is of conventional configuration and which is attached to a valve operator 56 which is adapted to operate the plug for rotational and vertical motion by means of a lever 58 in a manner disclosed in the aforementioned copending patent application.

It should be understood that the present invention does not include and is not dependent upon the type of operator mechanism that is utilized with a tapered plug valve to effect the necessary sequential vertical and rotational motion needed to open and close the valve and that therefore the particular operator mechanism disclosed in Fig. 2 is merely of an exemplary nature which has been disclosed for the purpose of completeness. More specifically, irrespective of a type of operator utilized, the motion of the plug 50 to accomplish opening and closing of the valve remains the same. For example, in the configuration illustrated in Fig. 2 the plug is shown in its closed position with plug 50 in its most downward position and with waterway 52 rotated to a position in which its axis is perpendicular to the axis of aligned inlet 42 and outlet 44.In this position, maximum lateral pressure is applied against at least one slip 60 which, in turn, forces a seal 62 against the inside surface of inlet 42 thereby assuring an effective and leak-proof seal for the valve in its closed position. From this position, opening of the valve 40 is accomplished by first imparting a vertical motion to plug 50 which retracts slip 60 and thus seal 62 from the interior surface of inlet 42 and subsequently -imparting rotation motion to plug 50 to align waterway 52 with inlet and outlet 42 and 44 respectively.

The present invention relates to an inverted trunnion 64 as well as to the modified configuration of plug 50 as compared to the prior art valve illustrated in Fig. 1. More specifically, as seen in Fig. 2, a generally cylindrically shaped trunnion 64 is formed as an integral portion along the inside bottom surface 66 of valve body 48 with its terminal or free end 68 being on the upper side of the trunnion. Furthermore, unlike the prior art configuration illustrated in Fig. 1, plug 50 in the embodiment illustrated in Fig. 2 does not have a lower extending trunnion but has instead a flat bottom with an aperturethrough the lower portion of the plug leading into the waterway 52 and of suitable dimension for receiving inverted trunnion 64 there through.

In fact, in the closed position of the valve as illustrated in Fig. 2, plug 50 is, in effect, sitting on the inside surface of the bottom 66 of the valve body 48 with its lower aperture positioned concentrically around the lower portion of inverted trunnion 64. In this configuration the inverted trunnion 64 extends into waterway 52 but that this is of no concern because the valve is in its closed position with fluid flow cut off. However, it will be understood that when the valve is placed in its open position, plug 50 will have been raised vertically to unseat slip 60 and seal 62 and that vertical motion of the plug will raise waterway 52 sufficiently to preclude inverted trunnion 64 from extending into the waterway.In this configuration inverted trunnion 64 extends only through the aperture in the lower portion of plug 50 until the top surface 68 of the inverted trunnion is about flush with the bottom inside surface of waterway 52. As a result, it will be observed that the inverted trunnion does not in any way interfere with the fluid flow through the valve 40 when it is in its open position.

It should be observed that as a result of the novel configuration utilizing the inverted trunnion of the present invention, the valve 40 is significantly modified as compared to the prior art valve 10 of Fig. 1. More specifically, it is seen that no receptacle analogous to receptacle 30 of plug 10 of Fig. 1 need be provided and as a result, the bottom surface 66 of valve body 48 is flat thereby reducing the overall height of the valve and permitting the valve to become a stand-alone device without the protrusion built into the lower plate 1 8 illustrated in the prior art configuration of Fig.

1. Furthermore, it is seen that there is no sediment trapping area and there is no need for a drain hole or drain plug as described above for the prior art configuration illustrated in Fig. 1.

Reference will now be made to Figs. 3 and 4 for a more detailed description of the closed and opened configurations respectively of a valve utilizing the present invention. More specifically, as seen in Fig. 3, the inverted trunnion 64 of the present invention is an integral part of the valve body 48 extending vertically from the inner surface of the valve bottom portion 66 and terminating in a terminal end 68 which is located slightly below the inner surface of waterways 43 and 45 of inlet and outlet 42 and 44, respectively. It is further seen in Fig. 3, the valve as illustrated in this figure in its closed configuration with plug 50 rotated so that its waterway 52 is perpendicular to waterway channels 43 and 45.Furthermore, valve operator 56 is in the position necessary to place plug 50 in its lowermost vertical position whereby the tapered shape of the plug 50 has the effect of applying substantially radial pressure against slip 60 thereby forcefully engaging seal 62 with the inner surface of inlet 42. As illustrated in Fig. 3, a second slip shown in phantom line may optionally be included on the outlet side of the valve body 48 to provide a double seal if desired. In this closed position, inverted trunnion 64 extends through a plug/trunnion aperture in the bottom portion of plug 50 causing inverted trunnion 64 to extend into the plug waterway 52 which of course is of no concern because the valve is in its closed position.

On the other hand, in Fig. 4 it is seen that the lever 58 of valve operator 56 is now configured to place the valve 40 in its open configuration. In this configuration plug 50 has, as a result of the effect of the operator 56 on the upper trunnion 54, been moved vertically upwards to release the pressure against slip 60 and rotate it 90 degrees to align waterway 52 with inlet waterway 43 and outlet waterway 45 whereby permitting the free flow of fluid from inlet to outlet.It is to be observed that in this raised and rotated configuration of plug 50 relative to the remaining components of valve 40, inverted trunnion 64 now extends only partially through plug/trunnion aperture 70 in the lower portion of plug 50 whereby to still provide coaxial stabilizing effect on the plug operation without extending into waterway 52 which would otherwise partially obstruct the free flow of fluid through the valve. It is also to be observed that as a result of the rotation of plug 50, slip 60 and seal 62 have also been rotated 90 degrees, the plug and slip being rotated as a unitary combination as shown in the partially cut-away view of the slip 60 as seen in Fig. 4.

In Figs. 3 and 4 it will again be observed that as a result of the novel inverted trunnion configuration of the present invention, the valve bottom surface 66 of valve 40 is provided in a flat configuration and is free of drain plug and is configured to terminate much closer to the plug 50 whereby the valve 40 is now relatively free standing in configuration as compared to the prior art valve of Fig. 1. Furthermore, it will be seen that in addition to the overall height reduction of the valve resulting from the present invention, the trunnion receptacle 30 of the prior art valve of Fig. 1 has been omitted thereby doing away with a sediment trapping area.Finally, it can be seen that as a result of integrating the inverted trunnion 64 into the valve body structure 48, the valve of the present invention is more readily manufactured with fewer separate components and with fewer assembly steps.

It will now be understood that what has been disclosed herein comprises a novel tapered plug valve which utilizes an inverted trunnion integrated into the lower surface of the valve body and designed to extend through the tapered plug of the valve to provide the coaxially stabilizing effects of the former lower extending trunnion of the prior art valve but without the numerous disadvantages of such a prior art configuration. More specifically, as a result of the unique configuration of the present invention, the overall valve height has been reduced and the need for an extended lower plate has been deleted along with the sediment trapping area and drain plug configuration that are concomitant with such prior art lower plate configurations.

Those having skill in the art to which the present invention pertains will now appreciate as a result of the teaching herein disclosed, that numerous modifications and additions may be made to the present invention. By way of example, inverted trunnions of different shapes as well as different manufacturing processes for providing an inverted trunnion secured to the lower plate of the valve may now become apparent. However, all such modifications and additions are contemplated to be within the scope of the invention which is to be limited only by the claims appended hereto.

Claims (7)

1. In a valve of the type having an inlet, an outlet, an operator, a body forming a chamber, a tapered plug within said chamber, at least one wedge-shaped retracting slip and a seal on said slip for closing said inlet to flow, the plug of the type having an upper extending trunnion for coaxially stabilizing the plug during sequential vertical and rotational motions for opening and closing the valve; the improvement comprising: an inverted lower trunnion extending upwardly from the floor of said chamber coaxially with said upper extending trunnion of said plug, and an aperture in the lowermost surface of said plug, said aperture being adapted for receiving said lower trunnion in slideable substantially concentric engagement therewith whereby said lower trunnion also axially stabilizes said plug during both vertical and rotational motion of said plug.

2. The improvement as claimed in Claim 1, wherein said lower trunnion is integral with said floor of said chamber.

3. The improvement at claimed in Claim 1 or Claim 2, wherein said plug comprises a waterway for alignment with passages through said inlet and said outlet when said valve is opened, and wherein said lower trunnion extends into said waterway when said valve is closed.

4. The improvement as claimed in Claim 3, wherein said lower trunnion extends into said aperture but not into said waterway when said valve is opened.

5. The improvement as claimed in anyone of the preceding claims, wherein said lower trunnion and said aperture are of circular cross-section.

6. The improvement as claimed in anyone of Claims 1, 2, 3, 4, or 5, wherein said valve body is substantially flat along the lowermost exterior surface thereof and wherein said flat surface is closer to said operator than the lowermost positions of said inlet and said outlet, respectively.

7. A valve substantially as hereinbefore described, with reference to, and as shown in Figs. 2-6 of the accompanying drawings.