Force equilibrium of a valve rod due to internal pressure equalization

An apparatus includes a safety shut-off valve for use with a gas regulator. The safety shut-off valve includes a housing, a valve rod, a vent chamber, and a vent line. The housing includes an interior chamber configured to regulated pressure in a fluid. The valve rod is disposed in the housing and controls a valve for interrupting the fluid in the internal chamber. The vent chamber receives ambient air and maintains pressure equalization of the ambient air and the fluid within a maximum pressure of the fluid. The vent line is disposed in a center of the valve rod and provides fluid communication of the ambient air between the vent chamber and an outside of the housing.

TECHNICAL FIELD

This disclosure relates generally to gas pressure regulators. More specifically, this disclosure relates to a force equilibrium of a valve rod due to internal pressure equalization.

BACKGROUND

High pressure in a main valve housing causes essential forces on the casing wall and all components located inside. As long as the whole part is inside the casing, no difficulties are expected from the essential forces.

For example, a guided valve rod is installed in such a housing. Rotatory and transitory motion of the valve rod is possible. The applied pressure (puor pd) inside the housing causes forces on a part (e.g. vale rod, valve stem, shaft, etc.) that intrudes into a housing, but does not penetrate it completely. In this case, a kind of imbalance is experienced due to a different pressure inside the housing and the ambient pressure outside it. Regarding a pressure increase and enlargement of the valve rod sectional cross area, the imbalance has an exponential impact on big forces. In order to avoid this disequilibrium, a pressure equalization is needed.

SUMMARY

This disclosure provides a force equilibrium of a valve rod due to internal pressure equalization.

In a first embodiment, a regulator includes a housing, a valve rod, a vent chamber, and a vent line. The housing includes an internal chamber regulates pressure in a fluid. The valve rod is located in the housing and controls a valve for interrupting the fluid in the internal chamber. The vent chamber receives ambient air and maintains pressure equalization of the ambient air and the fluid within a maximum pressure of the fluid. The vent line is located in a center of the valve rod and provides fluid communication of the ambient air between the vent chamber and an outside of the housing.

In a second embodiment, a valve rod is located in a housing of a safety shut-off valve for use with a gas regulator. The valve rod controls a valve for regulating fluid in an internal chamber of the housing. The valve rod includes a vent chamber and a vent line. The vent chamber receives ambient air and maintains pressure equalization of the ambient air and a fluid within a maximum pressure of the fluid. The vent line is located in a center of the valve rod and provides fluid communication of the ambient air between the vent chamber and an outside of the housing.

In a third embodiment, a method includes providing fluid communication of ambient air between a vent chamber in a housing of a safety shut-off valve and an outside of the housing; receiving ambient air in the vent chamber; receiving fluid in an internal chamber in the housing; maintaining pressure equalization of the ambient air and the fluid within a maximum pressure of the fluid; and interrupting the fluid received in the internal chamber using a valve connected to a valve rod.

DETAILED DESCRIPTION

A imbalance or disequilibrium issue is applied to respective standards Deutsches Institu Fur Normung (DIN EN) 334 and DIN EN 14382 for gas pressure regulators and safety devices for gas pressure regulating station and installations, which includes gas safety shut-off devices for inlet pressures up to 100 bar.

Gas pressure regulators (also known as gas regulators, pressure control valves, or pressure regulating valves) regulate the pressure in a high pressure gas system. A gas regulator allows high pressure gas to flow into an orifice, and when the gas exits the valve, the gas pressure is reduced or stabilized or both. Generally, a flexible diaphragm is attached to a disk by a mechanical linkage. The diaphragm covers an internal chamber such that one side of the diaphragm is exposed to loading pressure and the other side of the diaphragm is exposed to the inlet pressure. The high pressure gas flows through an inlet orifice that can be opened and closed by the disk and the linkage, which are attached to the diaphragm. The diaphragm is also attached to a closing spring. The diaphragm moves in response to the balance of the set pilot loaded pressure and the outlet pressure.

Typically gas pressure regulators are purely mechanical devices that regulate gas pressure. Certain gas pressure regulators are electro-mechanical, pneumatic, or electro-pneumatic that operate a gas pressure regulator under a process change condition. For example, an electro-mechanical gas pressure regulator regulates and controls pressure of the gas at the outlet. Controlling pressure can be achieved by a predetermined remote set-point adjustment and establishing automatic load limiting states. In another example, an electrical sensor can be added to a gas pressure regulator that can notify an operator when the device fails. However, in an industrial process environment, when a gas pressure regulator fails, the process can be forced to shut down. Various industrial process environments often utilize a redundancy system such that when the active pressure regulator valve fails, a backup is already in the system to regulate the gas pressure eliminating any down time.

Generally, gas pressure regulators vibrate as the devices exhibit unstable tendencies. For example, gas pressure regulators often vibrate, or hum while in use. In certain embodiments, the vibrations increase based on the flow rate, pressure, temperature as well as the physical parameters of the gas pressure regulator. Physical parameters can include the volume of the various compartments within the gas pressure regulator as well as the size of the inlet and outlet piping. The frequency of the vibrations or humming of a gas pressure regulator can provide an indication as to the longevity of the gas pressure regulator. For example, if the frequency of the vibrations remains steady, then the gas pressure regulator is not in risk of failing. In contrast, if the frequencies of the vibrations are not steady or the magnitude of the frequency changes, then the pressure regulator could be in risk of failing. Many factors affect the frequency of vibrations such as the flow rate of the gas, the pressure and temperature of the gas as it flows through the gas pressure regulator

FIG. 1illustrates an example industrial process control and automation system100according to this disclosure. As shown inFIG. 1, the system100includes various components that facilitate production or processing of at least one product or other material. For instance, the system100can be used to facilitate control over components in one or multiple industrial plants. Each plant represents one or more processing facilities (or one or more portions thereof), such as one or more manufacturing facilities for producing at least one product or other material. In general, each plant may implement one or more industrial processes and can individually or collectively be referred to as a process system. A process system generally represents any system or portion thereof configured to process one or more products or other materials in some manner.

InFIG. 1, the system100includes one or more sensors102aand one or more actuators102b. The sensors102aand actuators102brepresent components in a process system that may perform any of a wide variety of functions. For example, the sensors102acould measure a wide variety of characteristics in the process system, such as pressure, temperature, or flow rate. Also, the actuators102bcould alter a wide variety of characteristics in the process system. Each of the sensors102aincludes any suitable structure for measuring one or more characteristics in a process system. Each of the actuators102bincludes any suitable structure for operating on or affecting one or more conditions in a process system.

At least one network104is coupled to the sensors102aand actuators102b. The network104facilitates interaction with the sensors102aand actuators102b. For example, the network104could transport measurement data from the sensors102aand provide control signals to the actuators102b. The network104could represent any suitable network or combination of networks. As particular examples, the network104could represent at least one Ethernet network, electrical signal network (such as a HART or FOUNDATION FIELDBUS network), pneumatic control signal network, or any other or additional type(s) of network(s).

The system100also includes various controllers106. The controllers106can be used in the system100to perform various functions in order to control one or more industrial processes. For example, a first set of controllers106may use measurements from one or more sensors102ato control the operation of one or more actuators102b. A second set of controllers106could be used to optimize the control logic or other operations performed by the first set of controllers. A third set of controllers106could be used to perform additional functions.

Controllers106are often arranged hierarchically in a system. For example, different controllers106could be used to control individual actuators, collections of actuators forming machines, collections of machines forming units, collections of units forming plants, and collections of plants forming an enterprise. A particular example of a hierarchical arrangement of controllers106is defined as the “Purdue” model of process control. The controllers106in different hierarchical levels can communicate via one or more networks108and associated switches, firewalls, and other components.

Each controller106includes any suitable structure for controlling one or more aspects of an industrial process. At least some of the controllers106could, for example, represent proportional-integral-derivative (PID) controllers or multivariable controllers, such as Robust Multivariable Predictive Control Technology (RMPCT) controllers or other types of controllers implementing model predictive control or other advanced predictive control. As a particular example, each controller106could represent a computing device running a real-time operating system, a WINDOWS operating system, or other operating system.

Operator access to and interaction with the controllers106and other components of the system100can occur via various operator consoles110. Each operator console110could be used to provide information to an operator and receive information from an operator. For example, each operator console110could provide information identifying a current state of an industrial process to the operator, such as values of various process variables and warnings, alarms, or other states associated with the industrial process. Each operator console110could also receive information affecting how the industrial process is controlled, such as by receiving setpoints or control modes for process variables controlled by the controllers106or other information that alters or affects how the controllers106control the industrial process.

Multiple operator consoles110can be grouped together and used in one or more control rooms112. Each control room112could include any number of operator consoles110in any suitable arrangement. In some embodiments, multiple control rooms112can be used to control an industrial plant, such as when each control room112contains operator consoles110used to manage a discrete part of the industrial plant.

Each operator console110includes any suitable structure for displaying information to and interacting with an operator. For example, each operator console110could include one or more processing devices114, such as one or more processors, microprocessors, microcontrollers, field programmable gate arrays, application specific integrated circuits, discrete logic devices, or other processing or control devices. Each operator console110could also include one or more memories116storing instructions and data used, generated, or collected by the processing device(s)114. Each operator console110could further include one or more network interfaces118that facilitate communication over at least one wired or wireless network, such as one or more Ethernet interfaces or wireless transceivers.

At least one of the sensors102ainFIG. 1could represent a gas pressure regulator. As noted above, the gas pressure regulator experience high pressures that put strong forces on the internal components.

In accordance with this disclosure, a technique is provided for reducing the forces experienced by the internal pressure at a valve rod. The vent line of the gas pressure regulator is relocated through the valve rod and out of the gas regulator at the base.

Additional details regarding the gas pressure regulator having a force equilibrium of the valve rod due to internal pressure equalization. Note that these details relate to specific implementations of the gas pressure regulator and that other implementations could vary as needed or desired.

AlthoughFIG. 1illustrates one example of an industrial process control and automation system100, various changes may be made toFIG. 1. For example, industrial control and automation systems come in a wide variety of configurations. The system100shown inFIG. 1is meant to illustrate one example operational environment in which a pressure sensor could be used.

FIG. 2illustrates an example device for force equilibrium of a valve rod due to internal pressure equalization according to this disclosure. In particular,FIG. 2illustrates an example computing device200. In some embodiments, the computing device200could denote an operator station, server, a remote server or device, or a mobile device. The computing device200could be used to run applications. The computing device200could be used to perform one or more functions, such as monitoring vibrations of a gas pressure regulator, generating and transmitting a notification based on the operational status of a gas pressure regulator, or recording and transmitting the vibrations associated with a gas pressure regulator. For ease of explanation, the computing device200is described as being used in the system100ofFIG. 1, although the device could be used in any other suitable system (whether or not related to industrial process control and automation).

As shown inFIG. 2, the computing device200includes at least one processor202, at least one storage device204, at least one communications unit206, and at least one input/output (I/O) unit208. Each processor202can execute instructions, such as those that may be loaded into a memory210. Each processor202denotes any suitable processing device, such as one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or discrete circuitry.

The memory210and a persistent storage212are examples of storage devices204, which represent any structure(s) configured to store and facilitate retrieval of information (such as data, program code, and/or other suitable information on a temporary or permanent basis). The memory210may represent a random access memory or any other suitable volatile or non-volatile storage device(s). The persistent storage212may contain one or more components or devices supporting longer-term storage of data, such as a read-only memory, hard drive, Flash memory, or optical disc.

The communications unit206supports communications with other systems or devices. For example, the communications unit206could include at least one network interface card or wireless transceiver facilitating communications over at least one wired or wireless network. The communications unit206may support communications through any suitable physical or wireless communication link(s).

The I/O unit208allows for input and output of data. For example, the I/O unit208may provide a connection for user input through a keyboard, mouse, keypad, touchscreen, or other suitable input device. The I/O unit208may also send output to a display, printer, or other suitable output device.

FIG. 3illustrates a gas regulator300with an external vent line according to this disclosure. The embodiment of the gas regulator300illustrated inFIG. 3is for illustration only.FIG. 3does not limit the scope of this disclosure to any particular implementation.

The gas regulator300provides accurate and reliable pressure reduction for an industrial process control and automation system100. The gas regulator includes an internal chamber305, a valve rod310, a vent line315, an impulse line320, and a housing325. The gas regulator300is used to ensure a reduced outlet pressure while providing a steady flow downstream.

The internal chamber305receives the fluid flow for the gas regulator300. The internal chamber305includes a diaphragm for pressure reduction/pressure regulating issue.

The valve rod310controls a valve330for interrupting the fluids/flow rate. The valve rod310is located in the center of the gas regulator300.

The vent line315is used to vent excess pressure buildup in the internal chamber above the valve rod. The vent line is located above the impulse line320. The vent line runs to the inside of the internal chamber.

The impulse line320is used for pressure supply of the pilot. The impulse line320is connected to a closest part of the internal chamber305a perpendicular distance from the outside wall of the gas regulator300.

A sensor102a, such as a pressure sensor, for a device200can be connected to the impulse line320. The sensor102acan mount to a pilot at one side of the gas regulator300. The sensor102adetects the pressure of the internal chamber305through the impulse line320. The device200receives the sensor reading and can provide the reading to a user or use the sensor reading to manipulate the gas regulator or other portions of the industrial process control and automation system100.

FIGS. 4A, 4B, 4C and 4Dillustrate a gas regulator400for increased flow rate according to this disclosure.FIG. 4Aillustrates a cross section of the gas regulator400according to this disclosure.FIG. 4Billustrates a connected vent line according to this disclosure.FIG. 4Cillustrates an impulse line on both sides of the main valve housing according to this disclosure.FIG. 4Dillustrates a gas regulator400with an internal vent line and increased flow rate according to this disclosure. The embodiment of the gas regulator400illustrated inFIGS. 4A-4Dare for illustration only.FIGS. 4A-4Ddo not limit the scope of this disclosure to any particular implementation.

The gas regulator400is structured for an increased flow rate in relation to the gas regulator300. The gas regulator400includes an internal chamber405, a valve rod410, a vent line415, an impulse line420, a housing425, a setting mechanism430, a vent chamber435, and valve440. The valve rod cast guidance2of valve rod410is turned 90° from the valve rod410and connected with the outer wall of the internal chamber405.

The vent line415is relocated in the interior of the valve rod410to vent the excess gas out of the housing at the base of the gas regulator400. The vent line415runs down the center of the valve rod410. The pressure equalization is accomplished by venting through the valve rod410.

The setting mechanism430of the valve rod410is connected with the upper internal small chamber above the valve rod guidance, so this creates an ambient pressure inside and ensures force equilibrium due to pressure equalization above the valve rod. The setting mechanism430allows ambient air to enter the vent chamber435before the valve440is engaged to interrupt the flow of fluid through the interior chamber405. The setting mechanism430then sets a ratio of a pressure of the ambient air in the vent chamber435to the maximum pressure of the fluid in the interior chamber405. Once the fluid in the interior chamber405has a pressure over the maximum pressure, the ambient air is forced out of the vent chamber435through the vent line415in the valve rod410. Once the ambient air is out of the vent chamber435, the vent line415engages the valve440to interrupt the flow of fluid in the interior chamber405. The air is vented out a vent hole445located at the base of the housing425.

The impulse line420is moved in a manner to run across the width of the gas regulator400providing access connections on both sides. The location of the impulse line420is structured to run tangential to the internal chamber405. A midpoint of the impulse line420is opened to the internal chamber.

In comparing the gas regulator300and the gas regulator400, adding a second impulse line320opposite of the current impulse line320in gas regulator300would cause additional problems. A second impulse line320would add more parts, which would increase the cost and manufacturing time. A second impulse line would require reducing the size of the internal chamber305or increasing the size of housing325, or both. A second impulse line320would alter the pressure readings of the first impulse line, which is why the impulse line420is connected at only one point of the internal chamber405.

A sensor102a, such as a pressure sensor, for a device200can be connected to the impulse line420. The sensor102acan mount to a pilot at one side of the gas regulator300. The sensor102adetects the pressure of the internal chamber305through the impulse line420.

In comparing gas regulator400and gas regulator300, the relocation of the vent line415and the impulse line420allows volume of the internal chamber405to be increased since the bores of the vent line315and impulse line320have been removed. Incorporating the vent line415into the valve rod provides for a housing425smaller and more compact than the housing325, reduces the amount of parts in the gas regulator400from the amount of parts in the gas regulator300. Adjusting the location and length of the impulse line420provides mounting options for pilots on opposite sides of the housing425.

FIG. 5illustrates an example method for force equilibrium of a valve rod due to internal pressure equalization according to this disclosure. For example, the method described inFIG. 5may be performed in conjunction with the gas regulator400inFIG. 4.

In operation505, the safety shut-off valve receives ambient air in a vent chamber. The ambient air can be at an ambient pressure to initialize the safety shut-off valve. The ambient air is received in the vent chamber through the vent hole at the base of the housing through the vent line located at a center of valve rod.

In operation510, the safety shut-off valve disengages a valve connected to the vent line opening up an interior chamber. The ambient air fills the vent chamber, which causes the valve rod to disengage the valve. When the valve is disengaged, a path for the fluid to flow through the interior chamber is exposed.

In operation515, the safety shut-off valve receives fluid in an internal chamber405. In certain embodiments, the fluid is a gas, such as natural gas, nitrogen, butane, propane, carbon dioxide, landfill gas, air, hydrogen, coke oven gas, argon, etc. The fluid is received through an inlet of the housing. The fluid received experiences pulsations due to a pump located upstream that is moving the fluid. The pulsation could cause the pressure of the fluid to rise or fall outside an operating range that the safety shut-off valve is set to regulate.

The gas regulator400regulates the fluid using a pilot controlled diaphragm. The valve rod410moves to interrupt the fluid entering the internal chamber405and the outlet of the regulator.

The impulse line420is located in the housing425and connected to the internal chamber405. The impulse line420runs tangentially to the internal chamber405. The impulse line420fluidly communicates with the internal chamber405at a midpoint and runs to opposite sides of the housing425. At each side of the housing, a pilot connection allows connection by a pilot or manometer to either side of the housing.

In operation520, the gas regulator400vents the ambient air from the vent chamber through a vent line415located in a valve rod410when the fluid is outside the operating pressure range. The vent line415provides internal pressure to the valve rod410. Due to the internal pressure, the valve rod410experiences pressure equalization with external pressure and forces. The ambient air is released from the regulator through a vent hole at the base of the housing. The vent hole used for both receiving and releasing ambient air from the safety shut-off valve.

In operation525, the safety shut-off valve engages the valve connected to the vent line to interrupt a flow of the fluid.

AlthoughFIG. 5illustrates one example of a method500for force equilibrium of a valve rod due to internal pressure equalization, various changes may be made toFIG. 5. For example, various steps shown inFIG. 5could overlap, occur in parallel, occur in a different order, or occur any number of times.