Claims
- 1. A bonnet and actuator assembly for use with a valve adapted for use in a line including a valve body and a valve member, the assembly being adapted to be connected to the valve body by bolts, comprising:
- a bonnet having a first outturned flange with bolt holes therein adapted to receive said bolts to bolt the bonnet to the valve body;
- an actuator housing;
- an actuator stem within said housing and adapted to be connected with said valve member in said valve body;
- stem actuator means in said housing and connected to said stem for moving the stem;
- a substantially imperforate shroud connected to said actuator housing and extending downwardly therefrom into engagement with said outturned flange outwardly of said bolt holes so as to protect said bolts connecting the bonnet with the valve body, when assembled thereon, from direct contact by heat from external fires and retarding heat induced deterioration of said bolts holding the bonnet to the valve body and,
- a plurality of fastener bolts having heads which are accessible externally of said shroud for releasably connecting said shroud to said bonnet, whereby said bolts can be removed without disconnecting said bonnet from said valve body.
- 2. The assembly of claim 1, including a second outturned flange on the bonnet above the first flange adapted to receive said fastener bolts and to provide a chamber therebetween to receive the heads or nuts of the bolts when the bonnet is bolted to the valve body.
- 3. The assembly of claim 2 wherein said chamber contains a heat insulating material for further retarding the application of heat to the bolts.
- 4. The assembly of claim 2 wherein the second outturned flange is integral with said bonnet.
- 5. The assembly of claim 2 wherein the second outturned flange is rotatably mounted on said bonnet so that the actuator can be angularly oriented in different positions.
- 6. The assembly of claim 1 wherein said stem actuator means includes a spring disposed within said shroud and connected to said actuator stem to urge the latter in one direction; a stop for limiting movement of the actuator stem in said one direction; said stem actuator means including a motor for moving the actuator stem in the opposite direction and having a releasable connection with the actuator stem permitting the motor, actuator housing and shroud to be moved upwardly as a unit and removed from the bonnet while the actuator stem and spring remain in or on the bonnet whereby inspection or repair to the motor or actuator housing can be made without bleeding down the line in which the valve body is installed.
- 7. The assembly of claim 6 wherein the connection of the spring to the stem includes a bearing permitting the spring to wind and unwind during movement of the actuator stem without exerting substantial torque on the actuator stem.
- 8. The assembly of claim 7 wherein the connection between the motor and actuator stem likewise includes a bearing permitting the stem to be rotated without exerting substantial torque on the motor.
- 9. The assembly of claim 6 wherein said stop is provided by a seat in the bonnet and a seat carried by the actuator stem for engagement with the bonnet seat to form a seal therewith upon predetermined outward movement of the actuator stem.
- 10. A bonnet and actuator assembly for use with a valve which includes a valve body and a valve member .Iadd.within the valve body for controlling pressurized fluid flow through the valve and that is serviceable while the valve remains in a pressurized state, comprising:
- a bonnet adapted to be connected to a valve body;
- an actuator housing;
- an actuator stem within said actuator housing and adapted to be connected with said valve member in said valve body;
- stem actuator means in said housing:
- means releasably connecting the stem actuator means with the actuator stem so that when the stem actuator means is released, it is slidable outwardly along said stem;
- said actuator housing having a sliding connection with the actuator stem;
- resilient means connected between the actuator stem and the bonnet urging the actuator stem outwardly of the actuator housing;
- stop means carried by the actuator stem and bonnet and limiting movement of the actuator stem outwardly of the actuator housing; and
- means releasably connecting the actuator housing to the bonnet which, when released, permits the actuator housing and stem actuator means to be removed from the bonnet .Iadd., allowing said actuator housing and stem actuator means to be slid outwardly along said actuator stem .Iaddend.while .Iadd.said actuator stem remains connected to the valve member within the valve body and the valve remains in the pressurized state, .Iaddend.the stop means .[.limits.]. .Iadd.limiting .Iaddend.outward movement of the actuator stem under the influence of said resilient means.
- 11. The assembly of claim 10 wherein the resilient means is a compression spring and its connection to the actuator stem includes a bearing permitting the spring to wind and unwind during movement of the actuator stem without exerting substantial torque on the actuator stem.
- 12. The assembly of claim 11 wherein the connection between the stem actuator means and the actuator stem like-wise includes a bearing permitting the stem to be rotated without exerting substantial torque on the stem actuator means. .Iadd.
- 13. A bonnet and actuator assembly for use with a valve adapted for handling fluids under pressure and which includes a valve body and a valve member within the valve body for controlling pressurized fluid flow through the valve and that is serviceable while the valve remains in a pressurized state, said assembly comprising:
- a bonnet adapted to be connected to the valve body;
- an actuator housing adapted to be connected to said bonnet in a fluid pressure isolation relation to the valve;
- an actuator stem within said housing and adapted to transmit valve opening and closing forces to said valve member through said bonnet;
- stem actuator means within said actuator housing for moving said actuator stem inwardly with respect to said bonnet;
- resilient means for urging said actuator stem outwardly with respect to said bonnet;
- stop means for limiting movement of said actuator stem outwardly with respect to said bonnet;
- means for releasably connecting said actuator housing to said bonnet;
- and means for releasably connecting said actuator housing to said actuator stem such that when said actuator housing is released form said bonnet, said stem actuator means is removable with said actuator housing from said bonnet and actuator stem while the flowpath of the valve remains in the pressurized state, said stop means limiting the outward movement of said actuator stem under the influence of said resilient means. .Iaddend. .Iadd.
- 14. The assembly as claimed in claim 13, wherein said resilient means includes:
- a spring retainer plate connected to said actuator stem below said stem actuator means;
- and a spring disposed about said actuator stem between said bonnet and said spring retainer plate. .Iaddend. .Iadd.15. The assembly as claimed in claim 14, including bearing means for permitting said spring retainer plate to rotate with respect to said actuator stem. .Iaddend. .Iadd.16. The assembly as claimed in claim 13, wherein:
- said stem actuator means includes a diaphragm connected to said actuator housing and a diaphragm plate connected to said diaphragm;
- and said means for releasably connecting said stem actuator means to said actuator stem includes a thrust element connected to said actuator stem, said diaphragm plate being abuttable with said thrust element to transfer downwardly directed force to said actuator stem, said diaphragm plate being movable upwardly with respect to said thrust member. .Iaddend.
- .Iadd.7. A valve actuator for use on a valve having a flowpath therein adapted for handling fluids under pressure and serviceable while the flowpath is in a pressurized state, said actuator comprising:
- an actuator housing adapted to be connected and disconnected in a fluid pressure isolating relationship to the flowpath of the valve with which the actuator is to be used;
- at least one actuator stem in said actuator housing longitudinally movable between a first and second position;
- stem actuator means in said actuator housing and in said pressure isolation relationship to the flowpath of the valve;
- means for effecting operable engagement between said stem actuator means and each actuator stem for urging each stem in an inward direction toward a selected one of its first and second positions such that inward movement of said stem actuator means causes inward movement of each actuator stem;
- said stem actuator means being operably disengaged from each actuator stem when each actuator stem moves in an outward direction such that said stem actuator means is free to be removed outwardly, relatively away from said engagement with each actuator stem while the flowpath of the valve remains in the pressurized state;
- and spring means operably retained during removal of said stem actuator means for urging each actuator stem toward the other of the selected first and second positions. .Iaddend. .Iadd.18. A valve actuator for use on a valve having a flowpath therein adapted for handling fluids under pressure and serviceable while the flowpath is in a pressurized state, said actuator comprising:
- an actuator housing adapted to be connected and disconnected in a fluid pressure isolation relationship to the flowpath of the valve with which the actuator is to be used while the flowpath of the valve is in the pressurized state;
- a diaphragm assembly mounted within said actuator housing, said diaphragm assembly including a diaphragm connected to said actuator housing and a diaphragm plate connected to said diaphragm;
- an actuator stem positioned in said actuator housing;
- a spring positioned about said actuator stem;
- means for transmitting forces generated in an outward direction by said spring to said actuator stem;
- means for transmitting inward forces from said diaphragm plate to said actuator stem and;
- said actuator housing and said diaphragm assembly being outwardly removable with respect to said actuator stem and said spring while the flowpath of the valve remains in the pressurized state. .Iaddend.
FIELD OF THE INVENTION
.Iadd.This application is a continuation of application Ser. No. 326,394, filed Mar. 20, 1989 now abandoned, which application is a continuation of application Ser. No. 106,994, filed Oct. 5, 1987, now abandoned, which application is a continuation of application Ser. No. 662,368, filed Oct. 18, 1984, now abandoned. .Iaddend..spsb.
This invention relates generally to valve actuator systems and, more particularly, concerns a valve actuator that is capable of providing protection for the bonnet structure of a valve during conditions of extreme heat, such as by external fires, thereby preventing heat induced deterioration of the pressure containing integrity of the valve mechanism for extended periods of time. Even more specifically, the present invention relates to a valve actuator mechanism that may be simply and efficiently repaired or replaced while the valve serviced thereby is allowed to be maintained under pressure during removal of the actuator from the valve mechanism.
When the bonnet structure of a conventional high pressure gate valve is assembled to the valve body, the bolts or studs and nuts that interconnect the body and bonnet structures are typically stressed quite highly in order to prevent leakage at the bonnet joint during periods when the valve is pressurized to its maximum operating pressure. Moreover, when the valve body is pressurized, these studs and nuts and bolts are subjected to considerable stress due to pressure acting on the seal area of the bonnet-to-body connection. In the event of a severe fire in close proximity to the valve and actuator mechanism, the studs and nuts or bolts that secure the bonnet to the valve body will become heated quite rapidly. In many cases, valve failure occurs during the excessive heat of direct flame impingement because the studs and nuts become heated to a temperature that reduces the strength thereof to the failure point. In many cases, it is desirable that valves be designed to remain safe and operative for extended periods of time even under circumstances where direct flame impingement causes rapid heating thereof. It is desirable, therefore, to prolong the time required for the studs and nuts of a bonnet-to-body connection to reach a temperature that reduces the strength of the studs and nuts to a level where failure occurs and the bonnet seal is lost. By prolonging the typical failure time of conventional valves, it is possible for the external fire to be extinguished before any high pressure valves can become heated to the point that stud and nut failure occurs. Obviously, in the case of combustible materials, such as petroleum products, it is highly desirable that fire induced valve failure be retarded in order to prevent the high pressure petroleum products from leaking from the bonnet connection and feeding the fire.
Another typical case of valve failure induced by the heat of external fires is the failure of the stem packing structure of the valve which ordinarily prevents internal valve pressure from escaping from the valve stem opening of the bonnet. Under circumstances of excessive heat, typical stem packing materials deteriorate quite rapidly and tend to allow stem leakage. It is desirable, therefore, to provide a valve and valve actuator mechanism having the capability of retarding transfer of the heat of an external fire to the valve stem packing and thereby retard any valve stem leakage that might otherwise occur. It is also desirable to provide the packing structure of the valve with means to promote introduction of a combination lubricant and sealant material by way of an exposed lubrication fitting even though the valve and valve actuator mechanism may be designed for retarding transfer of heat to the bonnet structure of the valve.
In many cases, pneumatic valve actuators are employed incorporating spring return features that induce mechanical movement of a valve stem to a predetermined position in opposition to the direction of movement induced by a pneumatic diaphragm controlled system. One of the problems with spring return of pneumatic diaphragms, however, is the degree of rotary force to which the diaphragm is often subjected as the compression spring winds and unwinds during compression and extension thereof during linear movement of the valve stem. In many cases it is also desirable to prevent introduction of rotational forces to the valve stem as well. It is desirable, therefore, to provide a valve actuator mechanism incorporating means to protect the diaphragm of the pneumatic actuator from spring-induced rotational forces during actuation thereof.
In some types of diaphragm type actuators, an actuator stem is threaded to the valve stem so that upon rotation of the actuator stem (e.g., manually), the valve stem is moved axially to open or close the valve. In such instances, it is desirable to minimize the torque applied to the diaphragm by the rotating actuator stem.
One of the serious disadvantages of pneumatic actuators, as well as many other types of valve actuators, is the inability of the valve actuators to be repaired and/or replaced while the valve associated therewith remains under pressure. Under circumstances where it is simply necessary to replace the diaphragm of a diaphragm type pneumatic actuator, it is frequently necessary to shut down the entire production line and deplete the pressure of the valve controlled by the actuator before the actuator can be disassembled for replacement or repair. It is desirable, therefore, to provide a pneumatic valve actuator mechanism that may be simply and efficiently removed for replacement or repair without necessitating complete shutdown and depressurization of the flow system that is controlled by the valve.
It is therefore a feature of the present invention to provide a novel valve actuator system that has the capability of providing a bolted bonnet type valve mechanism with protection against deterioration of the bolt and studs thereof by direct impingement of external fires on the valve and actuator assembly.
It is also a feature of this invention to provide a novel valve and actuator assembly wherein the stud and nut bonnet connection structures of the valve are encapsulated within a protective chamber and are insulated in order to retard transfer of the heat of external fires to the studs and nuts of the valve bonnet assembly.
It is an even further feature of this invention to provide a novel valve and actuator assembly wherein the stem seal structure of the valve mechanism is efficiently protected against the heat of external fires in order to retard transfer of heat to the stem packing structure of the bonnet and therefore retard the development of any heat induced stem leakage that might otherwise occur.
Among the several features of this invention is contemplated the provision of a novel pneumatic valve actuator mechanism that incorporates means to prevent transfer of rotary spring induced force to the diaphragm of the valve actuator and thereby prevent diaphragm deterioration that might otherwise be induced by winding and unwinding of the compression spring as it collapses and extends during linear movement of the valve stem.
It is also an important feature of this invention to provide a novel valve actuator mechanism that may be simply and efficiently removed from a valve and bonnet assembly while at the same time allowing the valve mechanism to be maintained under pressure and in safe condition.
In accordance with another feature of this invention, provision is made for efficient introduction of sealant material into the valve packing assembly even though the bonnet structure of the valve is encapsulated for the purpose of fire protection.
The present invention is directed to the provision of a pneumatic valve actuator for a valve wherein the primary force for causing the valve stem to move outwardly is developed by line pressure in the valve acting in the cross-sectional area of the stem. A compression spring is also provided to apply a secondary force to the stem to assure its outward movement when line pressure is low or absent. The stem is moved inwardly by pressure applied to a diaphragm connected to the stem. The compression spring bears against a spring plate that is interconnected with the valve stem by means of a bearing structure. The bearing structure reduces or eliminates torque from being applied to the stem and hence possibly to the diaphragm by winding and unwinding of the spring as it compresses and extends.
A diaphragm element is secured to a diaphragm plate that is also interconnected with the valve stem by means of a bearing structure. Rotational movement induced by rotating the stem is preventing from being transmitted to the diaphragm plate by the bearing mechanism. Thus, the diaphragm and valve stem are not subjected to rotational stresses as the actuator mechanism imparts operative movement to the valve stem in either direction thereof.
The unique relationship of the spring plate and diaphragm plate to the valve stem allows the actuator mechanism, with exception of the compression spring and spring plate assembly, to be simply and efficiently removed from the valve for repair or replacement. Removal of the actuator housing is accomplished simply by removing a minimum number of connection bolts that secure the actuator housing to the bonnet structure and by simply moving the actuator housing away from the valve to cause the desired separation. When the valve actuator is removed, the spring and spring plate remain in assembly with the valve stem. The compression return spring, therefore, continuously energizes the valve stem through the spring plate and maintains the valve stem at an outwardly extended position. This outwardly extended position of the valve stem may be a safe "open" or safe "closed" position, depending upon the location of the port in the gate. In most cases, however, the safe position of the valve is the closed position.
Under circumstances where the valve must be placed back on stream as rapidly as possible, a replacement actuator may be provided and may be simply and efficiently installed simply by moving the housing thereof onto the valve stem and bringing the diaphragm plate and bearing assembly into engagement with an appropriate shoulder defined on the valve stem. The replacement actuator may be simply bolted into assembly with the valve bonnet structure and the appropriate pneumatic connections may be made to complete the installation operation. The valve bonnet is formed to define an annular actuator support flange that is positioned in spaced relation with a typical bonnet flange that is designed for attachment to a valve body by means of studs and nuts. The actuator housing is formed to define an elongated connection portion or shroud that encircles the actuator connection flange and the bonnet flange. The actuator shroud cooperates with the bonnet structure to define an annular protective chamber within which the studs and nuts are located. This protective chamber may also be filled with a fire retardant heat insulation material that assists in protecting the studs and nuts from transfer of heat. Thus, the studs and nuts of the bonnet structure are protected against direct impingement by the flame and heat of a fire externally of the valve and actuator assembly. The actuator mechanism also protects the bonnet structure of the valve from corrosion in the event the valve is employed in a corrosive environment.
The actuator connection flange is formed to define a sealant passage and a sealant fitting is assembled to the bonnet structure to allow injection of sealant material into the packing chamber of the bonnet to enhance the sealing capability of the stem packing. By forming a sealant injection aperture in the stroud of the actuator housing, sealant material may be injected into the packing chamber at any time without necessitating removal of the valve actuator from the bonnet structure.
US Referenced Citations (22)
Continuations (3)
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Number |
Date |
Country |
| Parent |
326394 |
Mar 1989 |
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| Parent |
106994 |
Oct 1987 |
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| Parent |
662368 |
Oct 1984 |
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Reissues (1)
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Number |
Date |
Country |
| Parent |
148385 |
May 1980 |
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Patent Grant
RE33928
