Patent Application
20090260697
The present invention relates to fluid flow regulating devices such as gas regulators and, more particularly, to gas regulators having secondary devices sensing the same pressure from the same points of the devices, such as overpressure monitoring devices, slam shut devices, token alarm devices, and the like.
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 a 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 balanced trim to improve the reaction of the gas regulator to variations in the downstream pressure. The balanced trim is adapted to reduce the influence of the upstream pressure on the performance of the gas regulator. The upstream pressure is placed in fluid communication with a balancing diaphragm to apply a force to the control element of the gas regulator in the opposite direction as the force of the downstream pressure. Accordingly, as the upstream pressure varies, a corresponding force is applied to balance the force created by the upstream pressure as described further below so that the gas regulator acts in response to the downstream pressure only.
Some conventional gas regulators also include secondary devices, such as overpressure monitoring devices, slam shut devices, token alarms and the like, that perform a responsive action if a sensed input pressure, such as a pressure downstream of the regulator, varies from a predetermined normal operating pressure range. An overpressure monitoring device controls the pressure downstream of the regulator in the event that the regulator fails, thereby allowing the downstream pressure to increase to undesired levels. In the event the regulator fails and the downstream pressure rises above a predetermined monitor setpoint pressure, the overpressure monitoring device operates to close the valve port of the regulator valve and cut off the flow of gas to the downstream components of the gas distribution system. As demand increases and/or the problem with the regulator is resolved and the downstream pressure drops, the monitoring device opens the valve port and thereby allows gas flow downstream.
In other implementations, the gas regulators require safety devices to shut off the flow of gas if the regulator fails or other conditions develop that cause an overpressure or underpressure situation downstream of the gas regulator. Most commonly, slam shut safety valves are used to shut of the gas flow in one of these situations, or when either situation occurs. The slam shut safety valve may generally be disposed at or upstream of the regulator so that the slam shut valve may prevent gas from reaching the pressure reducing regulator in the event of the overpressure or underpressure conditions. The slam shut valve monitors gas pressure downstream of the gas regulator for maximum and minimum pressure tolerances. If the downstream pressure exceeds a maximum setpoint pressure or drops below a minimum setpoint pressure, the slam shut safety valve closes, cutting off the flow of gas to the gas regulator and preventing uncontrolled leak of gas. Once closed, the slam shut valve typically remains closed until service is performed and the slam shut valve is manually reset. In other implementations, it may be preferable to use a secondary device in the form of a token alarm device that does not relieve pressure in an overpressure situation, but instead bleeds an amount of the gas to produce an odor alerting the end customer to contact the gas provider for servicing of the gas regulator.
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, known as the setpoint pressure. The actuator 12 is therefore in fluid communication with the regulator valve 14 via a valve mouth 22 and an actuator mouth 24. The actuator 12 includes a control assembly 26 for sensing and regulating the outlet pressure of the regulator valve 14. Specifically, the control assembly 26 includes a diaphragm 28, a piston 30, and a control arm 32 having a valve disc 34 operatively connected thereto. The conventional balanced trim valve disc 34 includes a generally cylindrical body 36 and a sealing insert 38 fixed to the body 36. The control assembly 26 may also include a balanced trim assembly 40 with a balancing diaphragm 42 to offset the force applied to the valve disc 34 by the upstream pressure. The actuator diaphragm 28 senses the outlet pressure of the regulator valve 14 via a Pitot tube 44 placing the outlet 18 in fluid communication with the interior of the actuator 12 and a bottom-side of the actuator diaphragm 28. The control assembly 26 further includes a control spring 46 in engagement with a top-side of the diaphragm 28 to offset the sensed outlet pressure. Accordingly, the desired outlet pressure, which may also be referred to as the control pressure or the actuator setpoint pressure, is set by the selection of the control spring 46.
The diaphragm 28 is operably coupled to the control arm 32, and therefore, the valve disc 34 via the piston 30, controls 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 28 senses this decreased outlet pressure. This allows the control spring 46 to expand and move the piston 30 and the right-side of the control arm 32 downward, relative to the orientation of
In the conventional regulator 10 depicted in
While the release valve 50 operates to vent gas from the actuator 12, it typically does not relieve sufficient pressure to maintain the downstream pressure below the upper limit for which the regulator 10 is designed to regulate. For such situations, a secondary device such as those discussed above may be provided to control and cut off the gas flow, or minimally to alert the customer that an overpressure situations exists. In the configuration illustrated in
The monitor diaphragm 70 senses the outlet pressure of the regulator valve 14 via an external downstream pressure feedback line 84 connected to a port 86 of the monitor housing 66. The feedback line 84 places a downstream point remote from the regulator valve 14 in fluid communication with the interior of the monitor 60 and a bottom-side of the monitor diaphragm 70. The control assembly 68 further includes a control spring 88 in engagement with a top-side of the diaphragm 70 to offset the sensed downstream pressure. The desired setpoint or cutoff pressure is set by the selection and compression of the control spring 88. The diaphragm 70 is operably coupled to the control arm 74 and, therefore, the valve disc 76 via the piston 72, and controls the closing of the regulator valve 14 in an overpressure situation. A balancing spring 90 biases the valve disc 76 toward the open position as shown, and the piston 72 and control arm 74 are coupled so that the control arm 74 is only driven when the diaphragm 70 senses a downstream pressure greater than the cutoff pressure and flexes (not shown) upwardly to drive the piston 72. The diaphragm 70 and piston 72 also react to pressure decreases, but the piston 72 does not drive the control arm 74 when the downstream pressure is less than the cutoff pressure. In the event of a failure of the monitor 60, the monitor 60 may include a release valve 90 similar to the release valve 50 of the actuator 12 to vent gas into the atmosphere.
The regulator 10 having an actuator 12 and an overpressure monitor 60 as described above has two primary functions. First, the regulator 10 transfers a volume of fluid downstream while maintaining a consistent outlet pressure. Second, the regulator 10 ceases to allow fluid flow to the downstream portion of the distribution system if the outlet pressure can no longer be maintained by the regulator 10. As to the first function, a key aspect of the performance of the regulator 10 is how much fluid volume can be maintained at a certain pressure. To optimize the fluid volume, it is preferable to sense the downstream pressure as shown in
Performance can be compromised when the actuator 12 and a secondary device use different sensing locations, but external sensing is still predominantly used for overpressure monitors, slam shut valves, token alarms and other secondary devices. External sensing for secondary devices presents various problems. For example, piping downstream lines requires additional maintenance and can be costly for gas companies having many regulators in the field. Additionally, exposed downstream lines, if damaged, make the secondary devices inoperable. If the secondary device cannot sense the downstream pressure, the secondary device cannot cut off the fluid flow or otherwise signal that a problem exists, thereby leading the operators to the incorrect assumption that the regulator 10 is operating properly. Therefore, a need exists for an improved regulator having internal pressure sensing for both the actuator and the secondary device.
Internal pressure sensing for a secondary device has been provided in regulator valves configured to condition the fluid flow for more accurate pressure sensing at the outlet 18. The flow conditioning quickly transitions the fluid from turbulent flow to laminar flow to provide for more accurate sensing of the downstream pressure. In one example of flow conditioning shown in
In one aspect, the invention is directed to a fluid regulating device that may include a regulator valve having an inlet, an outlet, and a valve port disposed between the inlet and the outlet, an actuator coupled to the regulator valve and comprising an actuator valve disc, the actuator valve disc disposed within the regulator valve and adapted for displacement between a closed position engaging a downstream side of the valve port and an open position disposed away from the valve port, and a secondary device coupled to the regulator valve and configured to sense an input pressure and to perform a responsive action if the sensed input pressure varies from a secondary device setpoint pressure. The fluid regulating device may further include a Pitot tube having a first end with a sensing point disposed within the outlet of the regulator valve, a first branch extending toward the actuator, and a second branch extending toward the secondary device. The first end and the first branch of the Pitot tube may place the sensing point and the outlet in fluid communication with an interior of the actuator, and the first end and the second branch of the Pitot tube may place the sensing point and the outlet in fluid communication with an interior of the secondary device. The actuator may be configured to cause the actuator valve disc to move toward the valve port when the pressure at the sensing point of the Pitot tube increases and to cause the actuator valve disc to move away from the valve port when the pressure at the sensing point decreases to maintain a pressure downstream of the fluid regulating device approximately equal to a regulator setpoint pressure, and the pressure at the sensing point may be the input pressure of the secondary device.
In another aspect, the invention is directed to a fluid regulating device that may have a regulator valve having an inlet, an outlet, and a valve port disposed between the inlet and the outlet, an actuator coupled to the regulator valve and comprising an actuator valve disc, the actuator valve disc disposed within the regulator valve and adapted for displacement between a closed position engaging a downstream side of the valve port and an open position disposed away from the valve port, and a secondary device coupled to the regulator valve and configured to sense an input pressure and to perform a responsive action if the sensed input pressure varies from a secondary device setpoint pressure. The fluid regulating device may further include a Pitot tube having a first end with a sensing point disposed within the outlet of the regulator valve, a first branch extending toward the actuator, and a second branch extending toward the secondary device. The first end and the first branch of the Pitot tube may place the sensing point and outlet in fluid communication with an interior of the actuator, and the first end and the second branch of the Pitot tube may place the sensing point and the outlet in fluid communication with an interior of the secondary device. The actuator may be configured to cause the actuator valve disc to move toward the valve port when the pressure at the sensing point of the Pitot tube increases and to cause the actuator valve disc to move away from the valve port when the pressure at the sensing point decreases to maintain a pressure downstream of the fluid regulating device approximately equal to a regulator setpoint pressure, and the pressure at the sensing point may be the input pressure of the secondary device.
In a further aspect, the invention is directed to a dual sensing mechanism for a fluid regulating device that may have a regulator valve having an inlet, an outlet, and a valve port disposed between the inlet and the outlet, an actuator coupled to the regulator valve and comprising an actuator valve disc, the actuator valve disc disposed within the regulator valve and adapted for displacement between a closed position engaging a downstream side of the valve port and an open position disposed away from the valve port, and a secondary device coupled to the regulator valve and configured to sense an input pressure and to perform a responsive action if the sensed input pressure varies from a secondary device setpoint pressure. The dual sensing mechanism may include a Pitot tube having a first end with a sensing point disposed within the outlet of the regulator valve, a first branch extending from the Pitot tube toward the actuator, wherein the Pitot tube and the first branch place the sensing point and the outlet in fluid communication with an interior of the actuator e, and a second branch extending from the Pitot tube toward the secondary device, wherein the Pitot tube and the second branch of the Pitot tube place the sensing point and the outlet in fluid communication with an interior of the secondary device. The actuator may be configured to cause the actuator valve disc to move toward the valve port when the pressure at the sensing point of the Pitot tube increases and to cause the actuator valve disc to move away from the valve port when the pressure at the sensing point decreases to maintain a pressure downstream of the fluid regulating device approximately equal to a regulator setpoint pressure, and the pressure at the sensing point may be the input pressure of the secondary device.
Additional aspects of the invention are defined by the claims of this patent.
Although the following text sets forth a detailed description of numerous different embodiments of the invention, it should be understood that the legal scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment of the invention since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention.
It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘______’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term be limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. § 112, sixth paragraph.
With continued reference to
The actuator 112 includes a housing 130 and the control assembly 120, as mentioned above. The housing 130 includes an upper housing component 130a and a lower housing component 130b secured together with a plurality of fasteners, for example. The lower housing component 130b defines a control cavity 132 and an actuator mouth 134. The actuator mouth 134 is connected to the valve mouth 126 of the regulator valve 114 to provide fluid communication between the actuator 112 and the regulator valve 114. The upper housing component 130a defines a relief cavity 136 and an exhaust port 138. The upper housing component 130a further defines a tower portion 140 for accommodating a portion of the control assembly 120, as will be described.
The control assembly 120 includes a diaphragm subassembly 142, a disc and balancing subassembly 144, and a release valve 146. The diaphragm subassembly 142 includes a diaphragm 148, a piston 150, a control spring 152, a relief spring 154, a combination spring seat 156, a relief spring seat 158, a control spring seat 160, and a piston guide 162.
More particularly, the diaphragm 148 includes a disc-shaped diaphragm defining an opening through a central portion thereof. The diaphragm 148 is constructed of a flexible, substantially air-tight, material and its periphery is sealingly secured between the upper and lower housing components 130a, 130b of the housing 130. The diaphragm 148 therefore separates the relief cavity 136 from the control cavity 132.
The combination spring seat 156 is disposed on top of the diaphragm 148 and defines an opening disposed concentric with the opening in the diaphragm 148. As depicted in
The piston 150 of the disclosed embodiment includes a generally elongated rod-shaped member having a sealing cup portion 164, a yoke 166, a threaded portion 168, and a guide portion 170. The sealing cup portion 164 is concaved and generally disc-shaped and extends circumferentially about a mid-portion of the piston 150, and is located just below the diaphragm 148. The yoke 166 includes a cavity adapted to accommodate a coupler 172 which connects to a portion of the disc and balancing subassembly 144 to enable attachment between the diaphragm subassembly 142 and the disc and balancing subassembly 144, as will be described.
The guide portion 170 and the threaded portion 168 of the piston 150 are disposed through the openings in the diaphragm 148 and the combination spring seat 156, respectively. The guide portion 170 of the piston 150 is slidably disposed in a cavity in the piston guide 162, which maintains the axial alignment of the piston 150 relative to the remainder of the control assembly 120. The relief spring 154, the relief spring seat 158, and a nut 174 are disposed on the threaded portion 170 of the piston 150. The nut 174 retains the relief spring 154 between the combination spring seat 156 and the relief spring seat 158. The control spring 152 is disposed on top of the combination spring seat 156, as mentioned, and within the tower portion 140 of the upper housing component 130a. The control spring seat 160 is threaded into the tower portion 140 and compresses the control spring 152 against the combination spring seat 156. In the disclosed embodiment, the control spring 152 and the relief spring 154 include compression coil springs. Accordingly, the control spring 152 is grounded against the upper housing component 130a and applies a downward force to the combination spring seat 156 and the diaphragm 148. The relief spring 154 is grounded against the combination spring seat 156 and applies an upward force to the relief spring seat 158, which in turn is applied to the piston 150. In the disclosed embodiment, the force generated by the control spring 152 is adjustable by adjusting the position of the control spring seat 160 in the tower portion 140, and therefore the control pressure of the regulator 110 is also adjustable.
The control spring 152 acts against the pressure in the control cavity 132, which is sensed by the diaphragm 148. As stated, this pressure is the same pressure as that which exists at the outlet 118 of the regulator valve 114. Accordingly, the force applied by the control spring 152 sets the outlet pressure to a desired setpoint or control pressure for the regulator 110. The diaphragm subassembly 142 is operably coupled to the disc and balancing subassembly 144, as mentioned above, via the yoke 166 of the piston 150 and the coupler 172, and by a control arm 176.
The disc and balancing subassembly 144 includes an actuator stem 178 that is engaged by the control arm 176 to move the valve disc 122 between the open and closed positions as the diaphragm 148 flexes due to variations in the downstream pressure. Specifically, the actuator stem 178 is a generally linear rod having an end surface engaged by the control arm 176. The control arm 176 is a slightly curved rod and includes a fulcrum end 176a and a free end 176b. The fulcrum end 176a is pivotally coupled to the lower housing component 130b and includes a finger 180 having a rounded end and engaging the end surface of the actuator stem 178. The free end 176b is received between a top portion and a pin of the coupler 172 that is attached to the yoke 166 of the piston 150. Thus, the coupler 172 and the control arm 176 operably connect the disc and balancing subassembly 144 to the diaphragm subassembly 142.
The valve disc 122 of the disc and balancing subassembly 144 is operatively connected to the actuator stem 178, and includes a sealing insert 182 that engages the outlet of the valve port 128 to cut off the fluid flow through the regulator valve 114. The valve disc 122 is connected to the actuator stem 178 by a balanced port stem 184 and a balancing spring seat 186, and the combined elements are supported for linear movement by a stem guide 188, a retainer plate 190, a balancing diaphragm retainer 192 and a balancing port housing 194. The stem guide 188 is configured to fit within the actuator mouth 134, and includes a generally cylindrical inner portion that slidably retains the actuator stem 178. The stem guide 188 further includes channels 196 therethrough forming a portion of the path placing the outlet 118 in fluid communication with control cavity 132 as discussed further below.
The stem guide 188 engages the retainer plate 190, which is disposed between the stem guide 188 and balanced port housing 194, to hold the retainer plate 190 and balanced port housing 194 in place within the valve mouth 126. The retainer plate 190 is generally circular and includes a central opening through which the balanced port stem 184 passes. The balanced port housing 194 is generally cylindrical and hollow, extends toward the valve port 128, and has an inner diameter sized to slidably receive the valve disc 122. The diaphragm retainer 206 is disposed within the balanced port housing 194 and the opening of the retainer plate 190, and is held in place between a surface of the retainer plate 190 and an inner shoulder of the balanced port housing 194. A disc-shaped balancing diaphragm 198 having a central opening is provided within the balanced port housing 194. The balancing diaphragm 198 is constructed of a flexible, substantially air-tight, material and its periphery is secured between the diaphragm retainer 192 and the balanced port housing 194. The inner edge at the central opening of the balancing diaphragm 198 is sealingly secured between the valve disc 122 and the balanced port stem 184. The valve disc 122, balanced port stem 184 and the actuator stem 178 are biased toward the open position of the regulator valve 114 by a balancing spring 200 disposed between the spring seat 186 and a seating surface of the diaphragm retainer 192.
The balancing diaphragm 198 provides a force on the valve disc 122 in the direction of the valve port 128 to compensate for the force applied to the valve disc 122 due to the upstream pressure of the fluid passing through the valve port 128. The valve disc 122, balanced port stem 184 and diaphragm retainer 192 are configured to provide passages placing the surface of the balancing diaphragm 198 opposite the valve port 128 in fluid communication with the upstream pressure bearing on the valve disc 122. The components of the disc and balancing subassembly 144 are configured so that the force applied by the balancing diaphragm 198 is approximately opposite and equal to the force of the upstream pressure on the valve disc 122 to eliminate any influence of the upstream pressure on the diaphragm subassembly 142 and thereby allowing for more accurate control of the downstream pressure by the gas regulator 110.
In the illustrated embodiment, the regulator 110 also includes a secondary device in the form of an overpressure monitor 212 that operates to cut off the fluid flow through the regulator valve 114 in an overpressure situation until the downstream pressure is reduced after a failure of the actuator 112. The monitor 212 in the illustrated embodiment has a similar configuration as the actuator 112, and the same reference numerals with the leading “1” replaced by a leading “2” are used to refer to the corresponding elements of the monitor 212. The monitor 212 also operates in a similar manner as the actuator 112, with relevant differences being discussed further hereinafter.
Because the monitor 212 only responds in the event that the downstream pressure exceeds a cutoff pressure established by the diaphragm 248 and the control spring 252, the monitor diaphragm subassembly 242 and disc and balancing subassembly 244 are configured accordingly. A balancing spring 300 disposed between the spring seat 286 and the diaphragm retainer 292 biases the valve disc 22 to the normal open position as shown in
The disc and balancing subassembly 244 has a different configuration of components, but functions in a similar manner as the subassembly 144 of the actuator 112. A monitor mouth and balance port housing are combined in a coupling module 294 that connects the monitor 212 to a second valve mouth 226 of the regulator valve 114 disposed opposite the actuator 112 and on an upstream side of the valve port 128. The module 294 has an inner diameter sized to slidably receive the valve disc 222. The balancing diaphragm 298 is secured between the diaphragm retainer 292 and the balanced port housing 294 at the outer edge, and the inner edge at the central opening of the balancing diaphragm 298 is sealingly secured between the valve disc 222 and the balanced port stem 284. The valve disc 222, balanced port stem 284 and diaphragm retainer 292 are configured to provide passages placing the surface of the balancing diaphragm 298 opposite the valve port 128 in fluid communication with the upstream pressure bearing on the valve disc 222 to balance the force applied to the valve disc 222 by the upstream pressure.
The monitor 212 of
In addition to the actuator branch 304, a second branch 310 splits off from the main branch of the Pitot tube 302 in the direction of the monitor 212. In the illustrated embodiment, the monitor branch 310 extends to a passage or channel 312 through the wall of the regulator valve 114 proximate the outlet 118. The regulator valve passage 312 extends through the wall of the regulator valve 114 and aligns with an outer opening of a corresponding passage or channel 314 through the wall of the coupling module 294. The coupling module passage 314 similarly extends through the wall of the coupling module 294 and into the exterior of the monitor housing 230. Once through the monitor branch 310 and the passages 312, 314, the downstream pressure is communicated through the disc and balancing subassembly 244 to the control cavity 232 of the monitor 214.
When 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 from the outlet 118 and correspondingly the control cavity 132 of the actuator 112 and the control cavity 232 of the monitor 212, thereby reducing the pressure that is sensed by the diaphragms 148, 248. As the pressure sensed by the diaphragm 148 decreases, a force imbalance occurs between a control spring force and an outlet pressure force on the diaphragm 148 such that the control spring 152 expands and displaces the diaphragm 148 and piston 150 downward relative to the housing 130. This causes the control arm 176 to pivot in the clockwise direction, which in turn rotates the finger 180 relative to the surface of the actuator stem 178. This allows the actuator stem 178 and the valve disc 122 to move away from the outlet 124 of the valve port 128 due to the force of the balancing spring 200 to open the regulator valve 114. At the same time, the pressure decrease may also cause a force imbalance to occur between a control spring force and an outlet pressure force on the diaphragm 248 such that the control spring 252 expands and displaces the diaphragm 248 and piston 250 downward relative to the housing 230. However, because the upper portion of the coupler 272 is disposed remotely from the control arm 276, the monitor 212 does not similarly respond to the drop in pressure with movement of the valve disc 222.
When the demand is removed from the gas distribution system, such as when the user shuts off the appliance, the regulator 110 initially responds by decreasing the fluid flow through the regulator valve 114. As gas continues to flow through the valve port 128 and to the downstream portion of the system, the pressure increases at the outlet 118 and, correspondingly, in the control cavity 132 of the actuator 112 and the control cavity 232 of the monitor 212. As the pressure sensed by the diaphragm 148 increases and overcomes the control spring force, the diaphragm 148 and piston 150 are forced upward relative to the housing 130. The upward movement causes the control arm 176 to pivot in the counterclockwise direction, which in turn drives the actuator stem 178 and the valve disc 122 toward the valve port 128 to reduce the fluid flow through the regulator valve 114. Under normal operating conditions, the outlet pressure will drop to approximately the actuator setpoint pressure and remain there until the downstream demand changes in a manner that causes a response from by the actuator 112.
The monitor cutoff pressure is greater than the actuator setpoint pressure, and the monitor 212 does not typically respond to pressure variations within the normal operating range of the regulator 110. In the event of a failure of the actuator 112 such as, for example, the rupturing of the diaphragm 148, the valve disc 122 may remain open despite increases in the downstream pressure beyond the actuator setpoint pressure. Eventually, the pressure at the sensing point of the Pitot tube 302 reaches the cutoff pressure of the monitor 212. The downstream pressure communicated to the control cavity 232 by the monitor branch 310 causes a force imbalance to occur between the control spring force and the outlet pressure force on the diaphragm 248 such that the control spring 252 contracts and displaces the diaphragm 248 and piston 250 upward relative to the housing 230. When the piston 250 moves, the pin 272a of the coupler 272 rotates the control arm 276 to drive the actuator 278 and move the valve disc 222 into engagement with the valve port 128 to shut off the fluid flow through the regulator valve 114. The monitor 212 will continue to stop the fluid flow as long as the pressure at the sensing point of the Pitot tube 302 remains above the monitor cutoff pressure.
With the valve disc 122 disengaged from the outlet 124 of the valve port 128, the gas flows into the second portion 236 of the balanced port housing 194. Due to the configurations of the inner surface of the second portion 236, the valve disc 122 and the opening 242, the fluid is forced through the opening 242 and the baffles 244 disposed therein with relatively little divergence form the flow path. As the fluid passes through the baffles 244, turbulent fluid flow, to the extent any turbulence is present, is converted to laminar flow. Consequently, when the fluid reaches the outlet 118 of the regulator valve 114 and the sensing point of the Pitot tube 302, the smooth flow of the fluid allows for improved measurement of the downstream pressure and, correspondingly, improved regulation of the downstream pressure by the control assembly 120.
As mentioned above, the monitor 212 is but one type of secondary devices that may be used with regulators 110.
The upper case 414 (
At ends opposite the diaphragm 442, the overpressure spring 430 and the underpressure spring 432 contact or are seated against an overpressure adjustment cap 444 and an underpressure adjustment cap 446, respectively. The overpressure adjustment cap 444 and the underpressure adjustment cap 446 are displaceable along axis A towards and away from the diaphragm 442. In one embodiment, the overpressure adjustment cap 444 and the underpressure adjustment cap 446 may be threadedly engaged with the outer and inner casting tubes 436, 434, respectively. In particular, the overpressure cap 444 may be threadedly engaged to either an inner surface of the outer casting tube 436, or an outer surface of the inner casting tube 434. The underpressure cap 446 may be threadedly engaged with an inner surface of the inner casting tube 434. Both the underpressure cap 446 and the overpressure cap 444 are movable along axis A to adjust spring tension of the overpressure spring 430 and the underpressure spring 432 on the diaphragm plate 437. The distance between the adjustment caps 444, 446 and the diaphragm plate 437 determines the overpressure and underpressure set points for the slam shut safety device 410. Locating both the overpressure spring 430 and the underpressure spring 432 on the same side of the diaphragm 442 facilitates adjustment of both the overpressure spring 430 and the underpressure spring 432 from outside of the valve, and adjustments to the overpressure spring 430 and the underpressure spring 432 may be made independently of one another.
The diaphragm 442 (
The low pressure configuration includes a low pressure diaphragm plate 438, which is a rigid plate that covers the inner convolution 452b, the inner planar region 455, and the middle planar region 453 (
Turning again to
The valve body 412 also includes the reset pin assembly 470 for relatching the cam 462. The reset pin assembly 470 includes a reset rod 472, a relatch plug 474, a travel indicator 476 (
Once the over/underpressure condition is corrected, the reset pin assembly 470 may be used to relatch the cam 462. A user may displace one end of the reset rod 472 (the end disposed in the travel indicator) towards the interior of the valve body 412. In doing so, the relatch plug 474 may also be displaced and a second shoulder 475b of the relatch plug 474 may contact the third cam arm 463c, thereby forcing the cam 462 to rotate into the relatched position.
Dual sensing of the downstream pressure at both the actuator 112 and the slam shut safety device 410 may be achieved in a similar manner as discussed above in connection with the monitor 212. The Pitot tube 302 may have a similar configuration with the actuator branch 304 extending into the valve mouth 126 and the second branch 310 splitting off from the Pitot tube 302 in the direction of the secondary device, in this case the slam shut safety device 410. In this embodiment, the passage or channel 312 through the wall of the regulator valve 114 may be configured to align with an outer opening of a corresponding passage or channel 480 through the wall of the valve body 412 of the slam shut safety device 410. The channel 480 may extend through the valve body 412 to the interior of the device 410 to place the sensing point of the Pitot tube 302 in fluid communication with the interior of the device 410, or the channel 480 may be part of or extend to an upper passage or channel 482 of the valve body 412 that in turn places the interior of the device 410 in fluid communication with the sensing point.
With the illustrated configuration, the actuator 112 and the slam shut safety device 410 both sense the same outlet pressure from the outlet 118 of the regulator valve 114. Unlike the monitor 212 described above, the slam shut safety device 410 remains set in the open position with the slam shut plug 468 in the open position (not shown) disposed away from the valve port 128 during normal operation of the regulator 110 and under normal downstream pressures as sensed by the Pitot tube 302. However, when the downstream pressure at the outlet 118 outside the pressure limits or the device 410, the device 410 is triggered and the slam shut plug 468 engages the valve port 128 to cut off the flow of gas through the regulator valve 114. Consequently, in the event of an overpressure situation caused by a failure within the mechanism of the actuator 112 (e.g., punctured diaphragm 148, broken control arm 176, etc.), the pressure at the outlet 118 may exceed the setpoint pressure of the overpressure spring 430 and cause the cam 462 to rotate counterclockwise, release the latch and allow the slam shut plug 468 to move to the closed position. Conversely, during an underpressure condition caused by, for example, a rupture in a downstream gas line, the pressure at the outlet 118 may drop below the lower setpoint pressure of the underpressure spring 432 to allow the spring 432 to move the plunger 464 downward and rotate the cam 462 counterclockwise until the latch connected to the cam arm 463a releases to allow the slam shut plug 468 to move and engage the valve port 128.
The regulator 110 having internal dual downstream pressure sensing via the Pitot tube 302 disposed within the outlet 118 of the regulator valve 114 facilitates implementation in gas distribution systems without the necessity of downstream pressure feedback lines. By eliminating the external pressure feedback lines, installation of the regulator 110 is simplified to the attachment of the regulator valve 114 to the upstream and downstream piping. The feedback line and an associated downstream port are eliminated, which may be particularly advantageous where space is limited by the presence of other components of the system. The reduction in parts also reduces maintenance requirements and costs, and eliminates external lines that are susceptible to damage that can make the monitors inoperable. Additionally, the dual sensing of the Pitot tube 302 allows both the actuator 112 and the secondary device to sense the same pressure at the same location, thereby eliminating performance issues that can arise due to inconsistencies the pressures that may exists at two distinct pressure sensing locations. The internal dual pressure sensing regulator 110 in accordance with the present disclosure provides an alternative to previous regulators that is less expensive to implement and is readily implemented in a variety of regulator valve sizes and body types.
While the preceding text sets forth a detailed description of numerous different embodiments of the invention, it should be understood that the legal scope of the invention is defined by the words of the claims set forth at the end of a patent claiming priority hereto. The detailed description is to be construed as exemplary only and does not describe every possible embodiment of the invention since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention.
This application claims the benefit of priority to U.S. Provisional Patent Application No. 61/046,788, filed on Apr. 21, 2008, entitled “Valve Body with Dual Sense Mechanism,” which is hereby expressly incorporated by reference herein
| Number | Date | Country | |
|---|---|---|---|
| 61046788 | Apr 2008 | US |
