The present subject-matter relates to pneumatic and hydraulic control systems for valve actuators of the type used in many industrial processes.
The flow of fluids and other substances carried in process transport pipes is typically controlled using a process valve. It may be necessary in an industrial process to close, to open, to lock, or to keep open the process valve, in response to specific conditions of the flow and the environment, such as a detected change in the flow rate inside the pipe, temperature inside and/or outside of the pipe, flow pressure, outside environment pressure, etc.
Conventional control systems for valve actuators are generally designed to respond to changes in the process flow in one of four modes: fail open, fail close, fail last, and fail last locked. The process valve is typically configured in one of the four modes with tubes leading to the actuator, forming a tube network. Such tube networks of the control systems have to be quite circuitous with multiple fittings and bends to include components such as filter regulators, speed controllers, and so forth. The tube networks also need to be customized for each of the four configurations and therefore demand qualified labor during the installation and maintenance.
The following summary is intended to introduce the reader to the more detailed description that follows, and not to define or limit the claimed subject matter,
According to a first aspect, the present subject matter provides a valve actuator control system. The control system includes a pneumatic directional valve operable to move the actuator, and also a manifold having multiple internal channels, each channel having a manifold inlet port and a manifold outlet port.
The pneumatic directional valve has a valve inlet port and a valve outlet port The manifold is mountable directly to the pneumatic directional valve and is fluidly connectible to it in alternative connections such that the manifold outlet port and manifold inlet port of one active internal channel communicate with the valve inlet port and valve outlet port, respectively, of the pneumatic directional valve, while the other, non-active internal channels are isolated from the pneumatic directional valve.
The control system also includes closures that block the manifold outlet port and manifold inlet port of the non-active internal channels.
The multiple internal channels of the manifold are configured to provide operability of the actuator control system in at least a plurality of fail modes.
In some examples, the multiple internal channels of the manifold are configured to provide operability of the actuator control system in any one of fail-open, fail-close, or fail-last modes.
In some examples, the multiple internal channels of the manifold are configured to provide operability of the actuator control system in any one of fail-open, fail-close, fail-last, or fail-last-locked modes.
According to another aspect, the present subject matter provides a pneumatic manifold for a directional valve that operates to move the actuator of a valve actuator control system. The manifold is connectable to the directional valve and comprises a unitary body having multiple internal channels, each with a manifold inlet port and a manifold outlet port. The manifold is connectable to the directional valve in alternative connections such that the manifold outlet port and manifold inlet port of one active internal channel communicate with the valve inlet port and valve outlet port, respectively, of the pneumatic directional valve. The multiple internal channels of the manifold are configured to provide operability of the actuator control system in at least a plurality of fail modes.
In some examples, the multiple internal channels of the manifold are configured to provide operability of the actuator control system in any of fail-open, fail-close, or fail-last modes.
In some examples, the multiple internal channels of the manifold are configured to provide operability of the actuator control system in any of fail-open, fail-close, fail-last or fail-last-locked modes.
According to another aspect, the present subject matter provides a manifold block for a directional valve that controls the actuator of a process valve. The manifold block is connectable to the directional valve and comprises a plurality of manifold valve ports that are adapted to receive a plurality of complementary ports of the directional valve. A plurality of manifold channels is located inside the manifold block, each of the manifold channels extending between at least two manifold ports being adapted to conduct pressurized air between them. The manifold block is configured to operatively connect the directional valve to a pressurized air supply in at least one of fail-open, fail-close, fail-last and fail-last-locked operating modes.
In some examples, the manifold block is configured so that the directional valve is adapted to control the actuator in at least one operating mode chosen from fail-open, fail-close, fail-last, and fail-last-locked.
In some examples, the directional valve is controlled by at least one pilot solenoid valve which is connected to at least two of the input and output manifold ports.
In some examples, the manifold block is a unitary body.
For a better understanding of the subject matter herein and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show at least one exemplary embodiment, and in which:
FIG, 4D shows a schematic representation of a conventional piloted three-position directional valve for a fail-last-locked configuration.
In the following description, specific details are set out to provide examples of the claimed subject matter. However, the embodiments described below are not intended to define or limit the claimed subject matter.
It will be appreciated that, for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements or steps. Numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments of the subject matter described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the present subject matter. Furthermore, this description is not to be considered as limiting the scope of the subject matter in any way but rather as illustrating the various embodiments.
In addition, as used herein, the wording “and/or” is intended to represent an inclusive-or. That is, “X and/or Y” is intended to mean X or Y or both, for example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof.
Examples of conventional control systems 30 and 60 for a process valve 32 actuated by actuator 34 are shown schematically at
It should be noted that the control system 30 may be pneumatic or hydraulic. Although pneumatic operation using air is described herein, the same operation and schematics can be used in a hydraulic control system 30, by replacing air with oil.
Depending on the type of the actuator 34 to be controlled and other requirements for the control system for the actuator 34, either a solenoid-operated directional valve 36 or a piloted directional valve 62 can be used in the control system for the actuator 34.
Shown at
Typically, a control system 30 for the actuator 34 of process valve 32 can operate in one of four configurations: fail-open, fail-close, fail-last, and fail-last-locked.
Each of the four configurations demands a specifically configured directional valve 36 or 62.
The five-port directional valve 36 (or 62) may be a five-port three-position directional valve or a five-port two-position directional valve, depending on the configuration it is used for.
In a fail-open configuration, the process valve 32 needs to open when there is a failure of the solenoid valve's electrical signal
The FO solenoid directional valve 36a may be in a rest position 110a (or home position, or default position), or in an activated position 120a. The A-port (represented schematically at
When the FO solenoid valve 36a is in its rest position 110a, the air, received from the filter 38 to the P-port 112a, passes from the P-port 112a to the B-port 114a. From the B-port 114a, the air passes via the tube 52 to the rod portion 132 of the actuator 34, pushing, the piston & piston rod 130 and expanding the rod portion 132. The air from the cap portion 134 of the actuator 34 returns through the tube 54 to the A-port 116a and passes through the directional valve 36a to the exhaust port 119a.
When the solenoid 100a is activated, the FO solenoid valve 36a is in the activated position 120a. In this activated position 120a, the air passes from the P-port 122a to the A-port 126a, the cap portion 134 of the actuator 34 is therefore filled with air, and the process valve 32 is closed.
When the solenoid 100a is deactivated the FO solenoid valve 36a is returned to the rest position 110a by means of the spring 102a. In the rest position 110a, the air is brought from P-port 112a to B-port 114a and returns from the A-port 116a to the exhaust valve port 119a. In this rest position 110a, the air pushed from the B-port 114a via the tube 52 fills the rod portion 132 of the actuator 34 and the piston & piston rod 130 retracts in the−z direction and opens the process valve 32. The air from the cap portion 134 exhausts through the tube 54 via the port 116a and then through the port 119a.
In a fail-closed configuration, the process valve 32 needs to close if there is a failure of the solenoid valve's electrical signal
Shown at
The FC solenoid directional valve 36b has a solenoid 100b for activation and a spring 102b. The FC solenoid directional valve 36b is in the activated position 120b when it is activated by the solenoid 100b and the air passes from the P-port 122b to the B-port 124b. The B-port 124b is connected to the rod portion 132 of the actuator 34, the rod portion 132 is filled with air, the rod is retracted in the−z direction and the process valve 32 is opened.
When there is no signal coming from the solenoid 100b, for example, when the industrial process has failed, the spring 102b moves the directional valve 36b to the rest position 110b. In the rest position 110b, the air passes from the P-port 112b to the A-port 116b and fills the cap portion 134 of the actuator 34 with air, thereby closing the process valve 32. The air from the rod portion 132 of the actuator then returns via the tube 52 to the port 114b and then exhausts through the port 118b.
Shown at
The B-port (represented schematically as 144 and 154 at
The first solenoid 104 can move the FL solenoid directional valve 36c into a first position 140, where the air passes from the P-port 142 to the A-port 146, filling the cap portion 134 with air. As the cap portion 134 is filled with air, the process valve 32 is closed. When the solenoid 104 is deactivated, the directional valve 36c remains in the first position 140.
When the second solenoid 105 is activated, it can move the FL solenoid directional valve 36c into a second position 150, where the air passes from the P-port 152 to the B-port 154, filling the rod portion 132 of the actuator 34 with air. As the rod portion 132 is filled with air, the process valve 32 is opened. When the solenoid 105 is deactivated, the directional valve 36c remains in the second position 150.
When the first solenoid 106 is activated, the directional valve 36d is in the first position 160 and the air passes from the P-port 162 to the A-port 166. The cap portion 134 of the actuator 34 is filled with air and the process valve 32 is closed. The air from the rod portion 132 returns (exhausts) through the B-port 164 to the exhaust valve port 168.
When the first solenoid 106 is deactivated, the first and the second springs 108 and 109 move the FLL solenoid directional valve 36d into the third (middle) position 180. In the third position 180, the FLL solenoid directional valve 36d is closed and no air passes from the P-port 182 to either the A-port 186 or the B-port 184.
When the second solenoid 107 is activated, the directional valve 36d is in the second position 170 and the air passes from the P-port 172 to the B,-port 174. In this case, the rod portion 132 of the actuator 34 is filled with air and the process valve 32 is opened. The air from the cap portion 134 exhausts through the A-port 176 to the exhaust valve port 179.
When the second solenoid 107 is deactivated, the first and the second springs 108 and 109 move the FLL solenoid directional valve 36d into the third (middle) position 180, closing the FLL solenoid directional valve 36d such that no air passes from the P-port to either the A-port or the B-port.
Referring back to
When the pilot valve 70a pushes the air to the FO piloted directional valve 62a, the FO piloted directional valve 62a is in the activated position 120a. In the activated position 120a, the air received by the P-port 122a is transmitted to the A-port 126a, and then through the pipe 54 to the cap-portion 134 of the actuator 34, thereby closing the process valve 32.
On failure of pilot valve 70a, it stops sending/transmitting air to the piloted directional valve 62a. With the absence of air from the pilot valve 70a, the spring 102a moves the directional valve 62a into its rest position 110a. In this rest position 110a, the input air from the P-port 112a is transmitted to the B-port 114a, and then, via tube 52, to the rod portion 132 of the actuator 34, thereby forcing the piston & piston rod 130 to move in the−z direction, opening the process valve 32.
Referring back to the conventional control systems 30 and 60 at
Referring now to
The manifold 200 comprises a plurality of manifold ports and a plurality of manifold channels. Each manifold channel may have two or more ports and may permit the air to pass in the manifold channel from at least one port to at least another port of the same manifold channel. Each manifold port may permit the air to enter and exit one of the manifold channels at an external surface 201 of the manifold 200. The manifold ports may be located at different sides (facets) of the manifold 200.
In at least one embodiment, the manifold channels of the manifold 200 may shorten or even replace the conventional tube network of the control system 30 (or 60). In at least one embodiment, the filter 38, a pressure relief valve, as well as exhaust flow control devices (valve/muffler), and/or other devices, may be operatively connected directly to the manifold 200.
In at least one embodiment, the manifold 200 may be operatively coupled to the directional valves 36 or 62. In at least one embodiment, five ports of the manifold 200 (ports 240, 242, 244, 246, and 248) may be adapted to receive the ports of the solenoid directional valve 36. The ports of the manifold 200 may be complementary to the ports of the directional valves 36 or 62.
The solenoid directional valve 36 for any one of the four configurations fail-open (36a), fail-closed (36b), fail-last (36c) or fail-last-locked (36d) as discussed herein may be operatively connected (coupled) to the manifold 200. The filter 38, at least one exhaust flow control device, as well as a pressure relief valve may also be operatively coupled to the ports of the manifold 200.
Referring to
Shown at
In at least one embodiment, the second input port 204 may be operatively connected to the pressure relief valve. In at least one embodiment, one or more of input ports may be plugged. Multiples of the internal channels offers the possibility of interconnecting different peripheral devices (such as a pressure relief valve and/or piloting solenoid valves) and/or simplifying interconnections on different faces of the manifold to optimize compactness of the final assembly. All unused ports, with the exception of the exhaust ports 224 and 226, must be plugged with appropriate plugs.
The manifold 200 may further comprise a first exhaust manifold channel 256 and a second exhaust manifold channel 258. The first exhaust channel 256 may have two manifold exhaust ports 242 and 224, and the second exhaust channel 258 may also have two manifold exhaust manifold ports 244 and 226. In at least one embodiment, the first and the second exhaust manifold ports 258 and 244 may be adapted to receive the first and the second exhaust valve ports 58 and 44 of the directional valve 36, such that the manifold 200 may be operatively connected to the directional valve 36.
The exhaust manifold ports 224 and 226 may be adapted to receive the exhaust flow control mufflers. If no accessories are required for the exhaust function, these ports are to be left opened.
The manifold 200 may further comprise an A-channel 254 and a B-channel 252, each having at least two ports. A first manifold A-port port 248 of the A-channel 254 may be adapted to connect to the A-port 48 of the directional valve 36. At least one exit manifold B-port (for example, port 231 or port 233) of the B-channel may be operatively connected to the actuator 34, the unused port is thus appropriately plugged.
A first manifold B-port 246 of the B-channel 252 may be operatively connected to the B-port 46 of the directional valve 36. At least one exit manifold B-port (for example, port 231 or port 233) of the B-channel 252 may be operatively connected to the actuator 34, the unused port is thus appropriately plugged.
In at least one embodiment, at least one exit manifold A-port may have one form and/or dimension and/or standard, and the other exit manifold A-port may have another form and/or dimension and/or standard. Similarly, at least one exit manifold B-port may have one form and/or dimension and/or standard, and the other exit manifold B-port may have another form and/or dimension and/or standard. For example, the exit manifold ports 233 (and/or 235) may have the NAMUR standard, and exit manifold ports 231 (and/or 237) may have the National Pipe Thread (NPT) standard. Having two different ports may allow reducing the number of components, such as adapters, to be used in the control system. ‘NAMUR’ describes a mechanical interface pattern used to mate a directional valve onto a flat surface and is typically used in pneumatic rotary actuators. Other port types can also be integrated such as BSP and SAE.
For example, when one manifold A-port 237 is used, the other A-port 235 may be blocked/plugged with an appropriate port plug (plug appropriate for the type of port, NPT, BSP, SAE, NAMUR).
Shown at
Shown at
The same manifold 200 may be operatively connected to receive any of the directional solenoid valves 36a, 36b, 36c, or 36d, each adapted to a different configuration, such as fail-open, fail-close, fail-last, and fail-last-locked,
The solenoid directional valves 36 and the piloted directional valves 62 typically have different dimensions. Nevertheless, the manifold 260 may be adapted to receive a solenoid direction valve 36, all the unused ports of the manifold 260 are plugged with the exception of the exhaust ports.
The pneumatic manifold control system for an actuator may comprise the directional valve 36 or 62, the pressure relief valve 199, the filter 38, and the manifold block 260. The manifold block 260 may connect using the manifold channels the filter 38, the pressure relief valve 199, and the directional valve 36 or 62, with each other and with the actuator 34.
As shown at
The directional valve may be the solenoid directional valve 36 or the piloted directional valve 62, piloted by at least one pilot solenoid valve 70 (and/or 74). The pilot solenoid valves 70 and/or 74, as shown at
As described herein, the pneumatic manifold control system for a valve actuator may operate in at least one of the control configurations. The control configuration of the pneumatic manifold control system may be one of fail-open, fail-close, fail-last, and fail-last-locked configurations and is dependent of the directional valve used in the system.
The manifold 260 may be attached to the plate 303, while the plate 303 may be attached to the actuator 34.
Different manifold blocks may be provided, each with the functionality indicated herein, to suit different size directional valves: a ¼ size manifold block to suit the ¼ size solenoid operated directional valve 36; a ½ size to suit the ½ size piloted directional valve 62; and a size 1 to suit a 1 size piloted directional valve also depicted by 62. The physical sizes of these blocks are: ¼ size−4 in long×4 in wide×1.5 in high; ½ size−8 in long×4 in wide×2.25 in high; and 1 size−10 in long×4.25 in wide×3.5 in high.
The manifold based control system offers numerous advantages over the existing methods used in the industry: increased reliability, compactness and cost effectiveness of the final assembly by eliminating the majority of external component interconnections, optimized modularity permits four different control schemes by changing a single component (FO, FC, FL, FLL), and simplifies the addition of numerous accessories, easy physical installation since the block is used as a mounting platform for all accessories, cost effective manufacturing of the block since it can be mass produced, numerous port options, configurations and physical installation possibilities permit its use in a wide scope of applications.
While the above description provides examples of the embodiments, it will be appreciated that some features and/or functions of the described embodiments are susceptible to modification without departing from the spirit and principles of operation of the described embodiments. Accordingly, what has been described above has been intended to be illustrative of the invention and non-limiting and it will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto.
Number | Date | Country | Kind |
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2961795 | Mar 2017 | CA | national |
Number | Date | Country | |
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62345955 | Jun 2016 | US |