Patent Application
20130312840
The present invention relates generally to valve actuators. More particularly the present invention relates to a valve actuator having improved reassembly ability and spring rotation prevention.
A valve is a device that regulates the flow of a substance. Valves are produced in a variety of different styles, shapes and sizes. Typically, valves are used for gases and liquids. However, valves are also used on solids capable of flow, slurries or any other substance capable of flow. Valves are used in almost every industry having a substance that flows.
One type of valve is a gate valve, also referred to as a sluice valve. A gate valve opens by moving a blocking element from the path of flow. The blocking element may be a round disk, a rectangular element, or a wedge. Gate valves have a blocking element and a seat forming a substantially leak proof seal. In a gate valve, the blocking element can be referred to as a gate valve block, a gate block or a block. In the open position, a gate valve has a bore where the substance is allowed to partially or completely flow through the valve. In a gate valve, the bore may be referred to a gate valve bore. When the gate valve bore is across the valve bore the gate valve is in an open position. When the gate valve block is across the valve bore, the gate valve is in a closed position.
Gate valves may be operated manually or automatically. One method to automatically operate a gate valve is to use an actuator. An actuator is a mechanical device for moving or controlling a mechanism or system. When an actuator is used in a gate valve, the actuator is typically linked to a stem to repeatedly move the valve gate between open and closed positions.
Actuators to open and close the gate valves may include manual operators, diaphragm-type operators, pneumatic operators and hydraulic operators. Often, a manual operator is combined with a manual operator with a diaphragm-type, pneumatic or hydraulic operator for back-up and test purposes. Additionally, the actuator may include a bonnet assembly, which interconnects the valve body and the valve gate, and a bonnet stem which is movable with the gate via an operator.
A manual operator is often seen combined with diaphragm or hydraulic operator for back up purposes. These combinations generally result in a top shaft extending from the operator. The extension of the top shaft may indicate whether the valve is open or closed.
It is often desirable to be able to repair the actuator without changing the bonnet assembly. This may prove difficult in implementation however, because of the numerous moving parts.
A modified actuator with fewer moving parts may be desirable to overcome this obstacle.
An additional adjustment device on a valve actuator located within the actuator housing may be desirable to overcome these obstacles.
In general, various embodiments of the present invention pertain to an actuator for moving a valve gate between open and closed valve positions within a valve body, the actuator comprising: an actuator housing comprising a pressurizeable chamber with an inlet port and an unpressurized chamber; a diaphragm positioned within the actuator housing and with a proximal side and a distal side positioned between the pressurized and unpressurized chambers and a diaphragm retainer plate also having a proximal side and a distal side, the diaphragm retainer plate abutting the proximal side of the diaphragm; a spring having an outer diameter, the spring being longitudinally positioned between a downstop nut and a bonnet ring; and a downstop nut.
In such embodiments, the downstop nut has a proximal side and a distal side; the distal side abutting the proximal side of the diaphragm retainer plate; and a plurality of downstop spring retainers spaced annularly around the proximal side of the downstop nut, the downstop spring retainers having an inner side orientated toward the spring such that the distance from the inner side of a downstop spring retainer to the inner side of another downstop spring retainer 180 degrees apart is greater than or equal to the outer diameter of the spring.
Still further, in such embodiments, there may be present a top shaft having a proximal and distal end, the proximal end abutting the distal side of the downstop nut; and an operator shaft having a proximal and distal end, the distal end affixed to the downstop nut and the proximal end extending through a bore of an internal packing retainer fitted within an internal bore of a bonnet, the bonnet connected to the bonnet ring and the valve body.
In the aforementioned embodiments, it is contemplated that the spring is capable of producing a biasing force opposing axial movement of the operator shaft toward the valve body; and wherein the operator shaft within the actuator housing is movable toward the valve body and defining a shaft axis, the actuator housing having a bore therethrough for receiving the operator shaft.
In certain further embodiments, the use of a diaphragm retaining nut is contemplated, in such embodiments, at least a portion of the diaphragm retaining nut abuts the distal side of the diaphragm, and at least a portion of the diaphragm retaining nut extends through the diaphragm and into a diaphragm retainer plate bore, positioned within the diaphragm retainer plate, wherein the portion of the diaphragm retaining nut extending through the diaphragm is affixed to the diaphragm retainer plate bore. In such embodiments, the portion of the diaphragm retaining nut extending through the diaphragm retainer plate bore may be threaded into the diaphragm retainer plate bore. Still further, in certain embodiments the top shaft has a flange at its proximal end, and the flange is positioned within the diaphragm retainer plate bore between the diaphragm retaining nut and the downstop nut.
Still further, concerning the top shaft, the top shaft flange prevents movement of the top shaft in a distal direction through the diaphragm retaining nut. In additional embodiments concerning the top shaft, the top shaft possesses a groove perpendicular to the shaft axis and distal to the diaphragm retaining nut fitted with a snap ring. In such embodiments, the snap ring prevents movement of the top shaft in a proximal direction through the diaphragm retaining nut.
In further embodiments of the inventions disclosed herein, the downstop nut possesses a downstop nut peg on the distal side of the downstop nut and the top shaft possesses a top shaft bore located at the proximal end of the top shaft and adapted to receive the downstop peg.
Still further, in certain embodiments of the inventions disclosed herein concerning the plurality of spring retainers, it is contemplated that the plurality of downstop spring retainers may form a continuous loop having an inner diameter around the downstop, and wherein the inner diameter is greater than or equal to the outer diameter of the spring.
Still further, in embodiments pertaining to the spring retainers, it is contemplated that latitudinal movement of the spring is prevented by the downstop spring retainers. Likewise, expansion of the spring in a latitudinal direction may be prevented by the downstop spring retainers.
In further embodiments of the invention concerning the internal packing retainer, both the internal bore of the bonnet and the internal packing retainer are threaded and the internal bore of the bonnet is adapted to receive the internal packing retainer.
In further embodiments of the invention, the downstop nut is threaded internally and is adapted to receive a threaded portion of the distal end of the operator shaft.
Other embodiments of the invention pertain to a method of preventing latitudinal movement of an actuator spring of a diaphragm actuator, the method comprising: obtaining an actuator housing having a distal end connected to a pressurizeable chamber and a proximal end connected to a bonnet via a bonnet ring; obtaining a diaphragm retainer plate positioned between the pressurizeable chamber of the actuator and an unpressurized chamber; and obtaining a downstop nut. In such embodiments, the downstop nut possesses a proximal side and a distal side; the distal side abutting a proximal side of a diaphragm retainer plate, the diaphragm retainer plate positioned between a pressurizeable chamber of the actuator and an unpressurized chamber; and the downstop nut possesses a plurality of downstop spring retainers spaced annularly around the proximal side of the downstop nut, the downstop spring retainers having an inner side orientated toward the spring such that the distance from the inner side of a downstop spring retainer to the inner side of another downstop spring retainer 180 degrees apart is greater than or equal to the outer diameter of the spring;
In such embodiments the method further comprises installing an actuator spring in a longitudinal position with a distal end abutting the downstop nut and positioned between the plurality of downstop spring retainers, and a proximal end abutting the bonnet ring; and wherein pressurization of the pressurizeable housing moves the diaphragm retainer plate in a proximal direction thereby compressing the spring, and wherein the downstop spring retainers prevent horizontal expansion of the spring during compression, latitudinal movement of the spring during compression or both.
In certain embodiments, the method further comprises centering the downstop nut with respect to a top shaft and an operator shaft of the actuator, the centering comprising placing a downstop peg of the downstop nut into a partial bore at the proximal end of the top shaft, and affixing a distal end of the operator shaft to the proximal side of the downstop nut.
In certain embodiments, the method further comprises positioning the distal side of the downstop nut against the proximal side of the diaphragm retainer plate, and wherein the downstop nut is held against the diaphragm retainer plate by a longitudinal force of the spring.
Still further, in certain embodiments, the method contemplates that rotational movement of the actuator spring is prevented by the interaction between the downstop nut and the actuator spring; prevented by the interaction between the bonnet ring and the actuator spring, or both.
In certain embodiments, the method further comprises affixing the operator shaft to the downstop nut further by screwing the operator shaft into a threaded internal bore of the downstop nut. Concerning the operator shaft, the method may further comprise the operator shaft having a shoulder and wherein the shoulder abuts a distal end of the gate bore.
The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
The following definitions and explanations are meant and intended to be controlling in any future construction unless clearly and unambiguously modified in the following examples or when application of the meaning renders any construction meaningless or essentially meaningless. In cases where the construction of the term would render it meaningless or essentially meaningless, the definition should be taken from Webster's Dictionary 3rd Edition.
Distal, in certain instances, can be defined as toward the top of the actuator and away from any valve on which the actuator rests.
Proximal, in certain instances, can be defined as toward a valve on which an actuator is mounted and away from the top of the actuator.
Referring now to the drawings, and more particularly to
Referring to
The top shaft 8 fits through the upper plug 7 of the top actuator housing 2. The top shaft has a proximal end pointed away from the diaphragm and a distal end pointed toward the diaphragm. Further, the top shaft is preferably formed from stainless steel. The top shaft 8 is preferably large enough in diameter to prevent bucking stresses when loaded by a manual override or a hydraulic override. The proximal end of the top shaft passes through the diaphragm retaining nut 13 and interacts with the downstop nut 20.
In certain embodiments, the top shaft further has a top shaft groove 15 around the circumference of the top shaft and immediately proximal to the diaphragm retaining nut 13. The top shaft flange 17 on the distal end of the top shaft prevents upward movement.
As depicted in
The diaphragm is held to the diaphragm retainer plate by the diaphragm retaining nut 13 which is positioned above or proximal to the diaphragm. The diaphragm retaining nut is preferably formed from stainless steel. Still further, the diaphragm retaining nut 13 is threaded and inserted through an opening in the center of the diaphragm 18 and screwed into the threaded diaphragm retaining plate 19, within the diaphragm retainer plate bore 40. Abutting the proximal side of the diaphragm retaining plate is a combination downstop and upper spring retainer that serves as both an upper spring retainer and a downstop, known as a downstop nut 20. The downstop nut 20 is preferably made of stainless steel. The distal end of the downstop nut forms a downstop peg 39 like protrusion fitting inside the proximal end of the top shaft, having a top shaft bore 39 adapted to receive the downstop peg.
One particular advantage of the downstop nut is the greater ease of assembly of the actuator by having fewer parts and in particular, fewer moving parts. In a conventional diaphragm actuator system, the upper spring retainer may disassociate from the downstop when the actuator is partially disassembled for adjustment of internal components. As a result, during assembly or reassembly, not only does the central spring (discussed below) need to be correctly positioned, the upper spring retainer needs to be correctly positioned as well. The development of the downstop nut 20 alleviates these problems.
As an additional consideration, in certain embodiments, such as illustrated in
Advantages of the downstop nut include the elimination of the extra task of trying to set a drift. By eliminating or combining an upper spring retainer ring to a downstop, both parts may be better centered within the actuator housing. Additionally, a one piece downstop is more economical in terms of worker time being spent during assembly and adjustment.
Further, the downstop nut possesses downstop spring retainers 36 as illustrated in
The downstop spring retainers further aid in the alignment of the spring within the actuator housing. Additionally, upon compression of the spring, the circumference of the spring can expand, causing the spring to shift in a latitudinal direction, thereby impacting alignment and causing the spring to have unwanted interactions with other components within the actuator. The downstop spring retainers
Still referring to
Still referring to
In other aspects of
As indicated previously, the internal bore of the bonnet ring is threaded. Threaded into the bonnet ring is the bonnet 25. Thus the actuator housing can be screwed onto the bonnet 25 via the bonnet ring 22. The tension on the central spring 21 can also be adjusted by rotating the actuator housing with respect to the bonnet. As illustrated in
The internal packing retainer has two o rings between its proximal and distal ends. O-rings are preferably Viton® o-rings. The operator shaft o-ring 28 surrounds the operator shaft 14 and is between the packing retainer 26 and the operator shaft 14. The packing retainer o ring 29 surrounds the internal packing retainer 26 and is in between the internal packing retainer 26 and the bonnet as illustrated in
Importantly, the packing retainer of the present invention is an internal packing retainer. By having an internal packing retainer which is affixed to the internal bore of the bonnet, the packing retainer is more secure than a traditional packing retainer which sits over a bonnet stem and is secured by a screw in the side of the packing retainer. A secure internal packing retainer, which is not connected to the bonnet ring or actuator housing, will resist loosening or disassociating with the bonnet if the actuator housing is rotated, thereby preventing worker injury or fatality.
Proximal to the packing retainer and within the bore of the bonnet are operator seals 30. Preferably the operator seals are Polypack™ seals. Perpendicular to the bonnet and proximal to the operator seals is a vent fitting 31 which transverses the bonnet from the exterior to the bore of the bonnet.
At the proximal end of the bonnet as depicted in
In the operation of this improved diaphragm actuator 1 of the present invention, pressure is applied through inlet port 5 in order to move both the diaphragm 18 and the diaphragm retainer plate 19 proximally toward the bonnet 25. The movement engages the downstop nut 20 to move the operator shaft 14 proximally toward the bonnet 25, until the downstop nut 20 contacts the drift shims 27. At this point, further movement in a proximal direction is prevented by the interaction between the downstop nut 20 and the drift shims 27. Further, at this point in operation, the operator shaft 14, which may be attached to a gate within a gate valve, will have repositioned the gate from a closed position to an open position.
Although the foregoing embodiments have focused on a diaphragm type actuator. It is conceivable and expected that the reduction in number of actuator parts afforded by the use of the downstop nut may be implemented in other actuator types.
As illustrated in
The foregoing detailed disclosure and description of the invention is illustrative and explanatory thereof, and it will be appreciated by those skilled in the art, that various changes in the size, shape and materials as well as in the details of the illustrated construction, reliability configurations, or combination of features of the various valve actuator elements of the present invention may be made without departing from the spirit of the invention.
