present invention relates to gas regulators, and more particularly, to gas regulators having actuators with closed-loop control.
The pressure at which typical gas distribution systems supply gas may vary according to the demands placed on the system, the climate, the source of supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with a predetermined pressure, and at or below a maximum capacity of the gas regulator. Therefore, gas regulators are implemented into these distribution systems to ensure that the delivered gas meets the requirements of the end-user facilities. Conventional gas regulators generally include a closed-loop control actuator for sensing and controlling the pressure of the delivered gas.
In addition to a closed loop control, some conventional gas regulators include a relief valve. The relief valve is adapted to provide overpressure protection when the regulator or some other component of the fluid distribution system fails, for example. Accordingly, in the event the delivery pressure rises above a predetermined threshold pressure, the relief valve opens to exhaust at least a portion of the gas to the atmosphere, thereby reducing the pressure in the system.
The actuator 12 is coupled to the regulator valve 14 to ensure that the pressure at the outlet 18 of the regulator valve 14, i.e., the outlet pressure, is in accordance with a desired outlet or control pressure. The actuator 12 is therefore in fluid communication with the regulator valve 14 via a valve mouth 34 and an actuator mouth 20. The actuator 12 includes a control assembly 22 for sensing and regulating the outlet pressure of the regulator valve 14. Specifically, the control assembly 22 includes a diaphragm 24, a piston 32, and a control arm 26 having a valve disc 28. The conventional valve disc 28 includes a generally cylindrical body 25 and a sealing insert 29 fixed to the body 25. The valve body 25 may also include a circumferential flange 31 integrally formed therewith, as depicted in
The diaphragm 24 is operably coupled to the control arm 26, and therefore the valve disc 28, via the piston 32 to control the opening of the regulator valve 14 based on the sensed outlet pressure. For example, when an end user operates an appliance, such as a furnace, for example, that places a demand on the gas distribution system downstream of the regulator 10, the outlet flow increases, thereby decreasing the outlet pressure. Accordingly, the diaphragm 24 senses this decreased outlet pressure. This allows the control spring 30 to expand and move the piston 32 and the right-side of the control arm 26 downward, relative to the orientation of
In the conventional regulator 10, the control spring 30 inherently generates less force as it expands towards an uncompressed length when displacing the control arm 26 to open the valve port 36. Additionally, as the control spring 30 expands, the diaphragm 24 deforms, which increases the area of the diaphragm 24. The decreased force supplied by the control spring 30 and the increased area of the diaphragm 24 in this operational scenario combine to create a regulator response wherein the force provided by the control spring cannot adequately balance the force generated by the diaphragm thereby resulting in an outlet control pressure that is less than that originally set by the user. This phenomenon is known as “droop.” When “droop” occurs, the outlet pressure decreases below its set control pressure and the regulator 10 may not function as intended.
In the conventional regulator 10 depicted in
When selecting a regulator for use in a particular application, technicians are charged with the task of maximizing flow capacity at the set control pressure while minimizing the amount of gas exhausted to the atmosphere under failure conditions. Typically, this task is accomplished by designing or selecting various aspects of the regulator 10, such as the valve port, to afford some compromise between these competing interests. In order to limit the amount of gas released to the atmosphere by the relief valve, technicians often choose the smallest port available to meet the required flow capacity.
The present invention provides an adjustable control element and/or a regulator, or other fluid flow control or regulating device. In one embodiment, an adjustable regulator constructed according to the principles of the present invention can include a valve body, a valve port, a valve disc, a diaphragm, and a shroud. The valve body defines an inlet and an outlet. The valve port is carried by the valve body between the inlet and the outlet. The valve disc is disposed within the valve body and adapted for displacement between an open position and a closed position to control the flow of a fluid through the valve body.
Additionally, in one embodiment, the valve disc can have a sealing surface for engaging the valve port when the valve disc is in the closed position. The diaphragm can be operably connected to the valve disc for controlling the position of the valve disc. The shroud is carried by the valve disc and extends axially beyond the sealing surface of the valve disc such that the shroud directs the flow of fluid through the valve port toward the outlet of the valve body when the valve disc is in an open position.
In one embodiment, the shroud can be an adjustable shroud that is adapted for axial displacement between a plurality of positions relative to the valve disc, thereby enabling the regulator to be tuned to meet particular desires.
In an alternative embodiment, either or both of the shroud and the valve disc can include indicia for indicating the position of the adjustable shroud relative to the valve disc.
In one embodiment, the shroud can include a cylindrical shroud in threaded engagement with the valve disc. In one form, the shroud is in threaded engagement with a periphery of the valve disc. In another form, the shroud may be wholly removable from the valve disc.
In accordance with another or an alternative embodiment, the regulator additionally include a plurality of shrouds. For example, a regulator can include a first shroud and a second shroud. Each of the first and second shrouds can be adapted to be interchangeably disposed on the valve disc to define different operational characteristics for the regulator. For example, the first shroud may extend a first distance beyond the valve disc to provide a first flow characteristic, while the second shroud may extend a second distance beyond the valve to define a second, different characteristic.
With continued reference to
The actuator 102 includes a housing 116 and the control assembly 122, as mentioned above. The housing 116 includes an upper housing component 116a and a lower housing component 116b secured together with a plurality of fasteners, for example. The lower housing component 116b defines a control cavity 118 and an actuator mouth 120. The actuator mouth 120 is connected to the valve mouth 112 of the regulator valve 104 to provide fluid communication between the actuator 102 and the regulator valve 104. In the disclosed embodiment, the regulator 100 includes a collar 111 securing the mouths 112, 120 together. The upper housing component 116a defines a relief cavity 134 and an exhaust port 156. The upper housing component 116a further defines a tower portion 158 for accommodating a portion of the control assembly 122, as will be described.
The control assembly 122 includes a diaphragm subassembly 121, a disc subassembly 123, and a release valve 142. The diaphragm subassembly 121 includes a diaphragm 124, a piston 132, a control spring 130, a relief spring 140, a combination spring seat 164, a relief spring seat 166, a control spring seat 160, and a piston guide 159.
More particularly, the diaphragm 124 includes a disc-shaped diaphragm defining an opening 144 through a central portion thereof. The diaphragm 124 is constructed of a flexible, substantially air-tight, material and its periphery is sealingly secured between the upper and lower housing components 116a, 116b of the housing 116. The diaphragm 124 therefore separates the relief cavity 134 from the control cavity 118.
The combination spring seat 164 is disposed on top of the diaphragm 124 and defines an opening 170 disposed concentric with the opening 144 in the diaphragm 124. As depicted in
The piston 132 of the disclosed embodiment includes a generally elongated rod-shaped member having a sealing cup portion 138, a yoke 172, a threaded portion 174, and a guide portion 175. The sealing cup portion 138 is concaved and generally disc-shaped and extends circumferentially about a mid-portion of the piston 132, and is located just below the diaphragm 124. The yoke 172 includes a cavity adapted to accommodate a coupler 135 which connects to a portion of the disc subassembly 123 to enable attachment between the diaphragm subassembly 121 and the disc subassembly 123, as will be described.
The guide portion 175 and the threaded portion 174 of the piston 132 are disposed through the openings 144, 170 in the diaphragm 124 and the combination spring seat 164, respectively. The guide portion 175 of the piston 132 is slidably disposed in a cavity in the piston guide 159, which maintains the axial alignment of the piston 132 relative to the remainder of the control assembly 122. The relief spring 140, the relief spring seat 166, and a nut 176, are disposed on the threaded portion 174 of the piston 132. The nut 176 retains the relief spring 140 between the combination spring seat 164 and the relief spring seat 166. The control spring 130 is disposed on top of the combination spring seat 164, as mentioned, and within the tower portion 158 of the upper housing component 116a. The control spring seat 160 is threaded into the tower portion 158 and compresses the control spring 130 against the combination spring seat 164. In the disclosed embodiment, the control spring 130 and the relief spring 140 include compression coil springs. Accordingly, the control spring 130 is grounded against the upper housing component 116a and applies a downward force to the combination spring seat 164 and the diaphragm 124. The relief spring 140 is grounded against the combination spring seat 164 and applies an upward force to the relief spring seat 166, which in turn is applied to the piston 132. In the disclosed embodiment, the force generated by the control spring 130 is adjustable by adjusting the position of the control spring seat 160 in the tower portion 158, and therefore the control pressure of the regulator 100 is also adjustable.
The control spring 130 acts against the pressure in the control cavity 118, which is sensed by the diaphragm 124. As stated, this pressure is the same pressure as that which exists at the outlet 108 of the regulator valve 104. Accordingly, the force applied by the control spring 130 sets the outlet pressure to a desired, or control pressure for the regulator 100. The diaphragm subassembly 121 is operably coupled to the disc subassembly 123, as mentioned above, via the yoke portion 172 of the piston 132 and the coupler 135.
Specifically, the disc subassembly 123 includes a control arm 126 and a stem guide 162. The control arm 126 includes a stem 178, a lever 180, and the control element 127. The control element 127 of the disclosed embodiment includes a valve disc 128 and a shroud 182. The stem 178, lever 180, and valve disc 128 are constructed separately and assembled to form the control arm 126. Specifically, the stem 178 is a generally linear rod having a nose 178a and a recess 178b, which in the disclosed embodiment is generally rectangular. The lever 180 is a slightly curved rod and includes a fulcrum end 180a and a free end 180b. The fulcrum end 180a includes an aperture 184 receiving a pivot pin 186 carried by the lower housing component 116b. The fulcrum end 180a also includes a knuckle 187 having an elliptical cross-section and disposed within the recess 178b of the stem 178. The free end 180b is received between a top portion 135a and a pin 135b of the coupler 135 that is attached to the yoke 172 of the piston 132. Thus, the coupler 135 operably connects the disc subassembly 123 to the diaphragm subassembly 121.
The stem guide 162 includes a generally cylindrical outer portion 162a, a generally cylindrical inner portion 162b, and a plurality of radial webs 162c connecting the inner and outer portions 162b, 162a. The outer portion 162a of the stem guide 162 is sized a configured to fit within the mouths 112, 120 of the regulator valve 104 and lower housing component 116b, respectively. The inner portion 162b is sized and configured to slidably retain the stem portion 178 of the control arm 126. Thus, the stem guide 162 serves to maintain the alignment of the regulator valve 104, the actuator housing 116, and the control assembly 122, and more particularly, the stem 178 of the control arm 126 of the control assembly 122.
With reference to
With continued reference to
When assembled, the shroud 182 can be attached to the periphery of the valve disc 128 such that the end surface 192 can be disposed generally parallel to and offset from the sealing surface 188 of the valve disc 128. Thus, when assembled, the sealing surface 188 is recessed from the end surface 192 of the shroud 182, thereby defining a generally cylindrical cavity 127a (shown in
However, in the event that an operating demand is placed on the gas distribution system, e.g., a user begins operating an appliance such as a furnace, a stove, etc., the appliance draws gas flow from the control cavity 118 of the regulator 100, thereby reducing the pressure that is sensed by the diaphragm 124. As the pressure sensed by the diaphragm 124 decreases, a force imbalance occurs between a control spring force and an outlet pressure force on the diaphragm 124 such that the control spring 130 expands and displaces the diaphragm 124 and piston 132 downward, relative to the housing 116. This causes the lever 180 to pivot in the clockwise direction about the pivot pin 186, which, in turn, rotates the knuckle 187 relative to the recess 178b in the stem 178. This moves the control element 127 away from the outlet 152 of the valve port 136 to open the regulator valve 104.
As the control spring 130 expands to displace the control element 127 and open the valve port 136, the force it generates reduces and the area of the diaphragm 124 increases. In the conventional regulator 10 described above with reference to
However, the control element 127 of the regulator 100 disclosed in accordance with this embodiment of the present invention includes the shroud 182 attached to the valve disc 128, which helps compensate for this “droop.” The shroud 182 is adapted to selectively extend beyond the sealing surface 188 of the valve disc 128 such that when the control element 127 is in this first operating mode or condition, the shroud 182 can direct the flow of gas flowing from the valve port 136 away from the diaphragm 124 of the actuator 102 and toward the outlet 108 of the regulator valve 104, as will be described. So configured, it should be appreciated that the shroud 182 may artificially induce a lower pressure or false pressure registration at the diaphragm 124 due to the restriction presented by the shroud 182. The lower sensed pressure at the diaphragm 124 causes the control spring 130 to bias the diaphragm 124 downward, which will further open the valve port 136. This will increase the flow of gas through the valve 104 to the outlet 108 and increase the outlet control pressure. Accordingly, the control element 127 of the disclosed embodiment provides for a “boost” to compensate for the “droop” that would otherwise occur.
As described above, the shroud 182 of the disclosed embodiment is adjustably attached to the valve disc 128. Therefore, the control element 127 may be tuned, for example, for different applications by adjusting the axial position of the shroud 182 relative to the valve disc 128, which in turn adjusts the degree to which the shroud 182 extends beyond the sealing surface 188 and directs the flow of gas to the outlet 108 of the regulator valve 104.
For example, as depicted in
In contrast,
Referring back to
As mentioned above, the shroud 182 is adjustably positioned relative to the valve disc 128 such that the amount of “boost” can be tuned. For example, the embodiment of the shroud 182 depicted in
In the event that a failure in the system occurs, the control element 127 of the disclosed embodiment does not affect the relief function of the regulator 100. Rather, as depicted in
Upon the pressure in the relief cavity 134 rising above a predetermined release pressure, the release valve 142 opens and exhausts gas through the exhaust port 156 to the atmosphere in a manner similar to that which is described above with reference to the conventional regulator 10 depicted in
The plurality of shrouds 282a, 282b, 282c are adapted to be interchangeably disposed on the body 285 of the valve disc 228. Thus, a technician may replace one shroud 282a, for example, with another shroud 282b, for example, to tune the control element 227 to achieve a particular flow characteristic for a particular application in a manner similar to tuning the control element 127 by adjusting the single shroud 182 described above.
For example, each of the plurality of shrouds 282a, 282b, 282c have different axial dimensions. Therefore, the impact of the control element 227 on the flow through the regulator valve 104 and therefore the outlet pressure depends on which shroud 282a, 282b, 282c is utilized. Otherwise, the shrouds 282a, 282b, 282c are identical. Specifically, each shroud 282a, 282b, 282c includes a generally cylindrical member, which can also be referred to as a collar or body, having an end surface 292 and an inner surface 294 including an inner chamfered surface 299. In one embodiment, the inner surface 294 of the shrouds 282a, 282b, 282c may be removably attached to the body 285 of the control disc 228 via a plurality of threads, a knurled connection, a set screw, or any other fixation device, or combination of fixation devices. Accordingly, because each of the shrouds 282a, 282b, 282c have different axial dimensions, they each extend a different distance beyond the sealing surface 288 of the valve disc 228, and therefore, provide different impacts on the flow and pressure of gas through the regulator valve 104 during normal operation.
Based on the foregoing, a regulator and/or a control element constructed in accordance with the present invention advantageously compensates for, reduces, and/or prevents “droop” from occurring by directing the flow of gas through the valve port 136 toward the outlet 108 of the regulator valve 104 and away from the actuator 102 without adversely affecting the performance of pressure relief within the regulator 100. Moreover, the adjustable and/or interchangeable control elements 127, 227 of the present invention advantageously provide for the ability to tune the regulator 100 for a variety of specific applications. While various embodiments of the regulator and control elements have been described herein, the present invention is not intended to be limited to these embodiments, but rather, is intended to include that which is defined by the scope and spirit of the following claims.
For example, one alternative embodiment of a control element constructed in accordance with the principles of the present invention may include a generally cup-shaped valve disc member and a plurality of inserts. The cup-shaped valve disc member may define a cavity and the inserts may have varying thicknesses, for example. The inserts therefore may be interchangeably disposed within the cavity of the valve disc to define different depths of the cavity, thereby providing for different impacts on the flow through the regulator valve 104. In one embodiment, the inserts may be magnetized inserts, threaded inserts, or merely friction-fit inserts. In another embodiment, the inserts may be stacked within the cavity to define different depths.
Moreover, the regulator 100 described herein is merely one example of a fluid control device incorporating the principles of the present invention. Other fluid control devices such as control valves may also benefit from the structures and/or advantages of the present invention.
The priority benefit of U.S. Provisional Patent Application No. 60/913,109, entitled “Adjustable Disc Mechanism for Gas Regulator,” filed Apr. 20, 2007, is claimed and the entire contents thereof are expressly incorporated herein by reference.
Number | Date | Country | |
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60913109 | Apr 2007 | US |