A high integrity pressure protection system (HIPPS) is a type of safety instrumented system (SIS) designed to prevent over-pressurization of a plant, such as a chemical plant or oil refinery. The HIPPS is arranged to shut off a source of high pressure before a predetermined upper threshold pressure of the system is exceeded. In this way, the HIPPS inhibits a loss of containment through rupture (explosion) of a line or vessel. The HIPPS is a barrier between a high-pressure and a low-pressure section of the plant.
In conventional systems, over-pressure is dealt with through relief systems. A relief system will open an alternative outlet for the fluids in the system once the upper threshold pressure is exceeded, to avoid further build-up of pressure in the protected system. This alternative outlet generally leads to a flare or venting system to safely dispose of the excess fluids. A relief system aims to remove any excess inflow of fluids for safe disposal, whereas a HIPPS aims to stop the inflow of excess fluids and contain fluid within the system.
Conventional relief systems have disadvantages such as release of (flammable and toxic) process fluids or their combustion products into the environment. With environmental awareness increasing, relief systems are not always an acceptable solution. Many other reasons exist why a plant may be best outfitted with a HIPPS.
In operation, the conventional HIPPS installation 10 uses the pressure transmitters 18, 22, 26 to monitor a pressure within the line 14. The logic solving circuit 38 receives signals from the pressure transmitters 18, 22, 26 indicative of the pressure. The logic solving circuit 38 then compares the measured pressures to a threshold value. If two or more of the pressure transmitters 18, 22, 26 indicate a pressure above the threshold value, then the logic solving circuit 38 will control the blocking valves 30, 34 via actuators and/or solenoids to close and inhibit flow through the line 14. The alarm 42 is also sounded so that a plant manager is alerted of the activation of the HIPPS installation 10.
The invention is directed to a manifold for connecting a pressure transmitter to a process fluid line in a HIPPS installation. One embodiment of the invention is directed to a high integrity pressure protection system (HIPPS) manifold that includes a housing providing a flow path between a process fluid line and a sensor, a first ball valve positioned within the housing and selectively allowing and inhibiting flow through the flow path, and a second ball valve positioned within the housing and selectively allowing and inhibiting flow through the flow path.
Another embodiment of the invention provides a high integrity pressure protection system (HIPPS) manifold that includes a housing providing a flow path between a process fluid line, a vent, and a sensor. A first valve is positioned within the housing and selectively allows and inhibits flow through the flow path. The first valve includes a first cam. A second valve is positioned within the housing and selectively allows and inhibits flow through the flow path. The second valve includes a second cam that interacts with the first cam. A third valve is positioned within the housing and selectively allows and inhibits flow through the flow path. The third valve includes a third cam that interacts with the second cam.
Another embodiment of the invention provides a high integrity pressure protection system (HIPPS) installation that includes three HIPPS manifolds. Each HIPPS manifold includes a housing that provides a flow path between a process fluid line, a vent, and a sensor. A first valve is positioned within the housing and selectively allows and inhibits flow through the flow path. A second valve is positioned within the housing and selectively allows and inhibits flow through the flow path. A third valve is positioned within the housing and selectively allows and inhibits flow through the flow path. The HIPPS manifold further includes a locking mechanism with a keyhole actuatable between a locked position and an unlocked position. A locking member is movable in response to the keyhole between a locked position and an unlocked position, thereby allowing actuation of the first valve when in the open position and inhibiting actuation of the first valve when in the locked position. The HIPPS installation further includes three individual keys, each key corresponding to one of the three keyholes and configured to actuate the associated locking mechanism.
Another embodiment of the invention provides a high integrity pressure protection system (HIPPS) installation that includes three HIPPS manifolds. Each HIPPS manifold includes a housing that provides a flow path between a process fluid line, a vent, and a sensor. A first valve is positioned within the housing and selectively allows and inhibits flow through the flow path. A second valve is positioned within the housing and selectively allows and inhibits flow through the flow path. A third valve is positioned within the housing and selectively allows and inhibits flow through the flow path. The HIPPS manifold further includes a locking mechanism with a keyhole actuatable between a locked position and an unlocked position. A locking member is movable in response to the keyhole between a locked position and an unlocked position, thereby allowing actuation of the first valve when in the open position and inhibiting actuation of the first valve when in the locked position. The HIPPS installation further includes a single key operable to fit in each of the three keyholes and configured to actuate the associated locking mechanism.
Another embodiment of the invention provides a method of operating a high integrity pressure protection system (HIPPS) manifold. The method includes inserting a key into a locking mechanism, actuating a locking member from a locked position to an open position, actuating a first valve from an open position to a closed position, actuating a second valve from an isolating position to a vent position after actuating the first valve to the closed position, and actuating a third valve from an open position to a closed position after actuating the second valve to the vent position.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.
As generally shown in
The locking mechanism 58 includes a lock housing 130, a key interface 134, a plunger 138 movable between a locked or extended position and an unlocked or retracted position, a spacer block 142, and a proximity switch/sensor 158. The lock housing 130 includes an aperture 146 sized to slidingly receive the plunger 138 and mechanical linkage (not shown) connecting the key interface 134 with the plunger 138. In other embodiments, the mechanical linkage could be replaced with an electrical system such as a solenoid operated mechanism.
The key interface 134 includes a keyhole 150 arranged to receive a key 154 (see
As shown in
The first valve 62 includes a two-way first ball valve 166 disposed within the first valve cavity 106, a first valve shaft 170 coupled to the first ball valve 166 and disposed within the first valve bore 118, a first cam 174 coupled to the first valve shaft 170, and a first handle 178 coupled to the first cam 174. A first end adapter 182 is threaded into the housing 54 to maintain the first ball valve 166 within the first valve cavity 106.
The second valve 66 includes a three-way second ball valve 186 disposed within the second valve cavity 110, a second valve shaft 190 coupled to the second ball valve 186 and disposed within the second valve bore 122, a second cam 194 coupled to the second valve shaft 190, and a second handle 198 coupled to the second cam 194. As shown in
The third valve 70 includes a two-way third ball valve 202 disposed within the third valve cavity 114, a third valve shaft 206 coupled to the third ball valve 202 and disposed within the third valve bore 126, a third cam 210 coupled to the third valve shaft 206, and a third handle 214 coupled to the third cam 210. The pressure transmitter adapter 86 is threaded into the sensor port 82 to maintain the third ball valve 202 within the third valve cavity 114.
The handles 178, 198, 214 are arranged so that they do not interfere with one another during actuation.
As shown in
Operation of the HIPPS manifold 50 will be described below with respect to
After unlocking the locking mechanism 58, the first valve 62 is free to be actuated. The first valve 62 is rotated, via the first handle 178, 90 degrees clockwise from an open position to a closed position (at 312). By rotating the first valve 62, the cam portion 230 is moved out of the proximity of the second valve 66 and instead the notch 234 is presented to the second valve 66. As shown in
With the cam portion 230 of the first valve 62 no longer blocking actuation of the second valve 66, the second valve 66 is rotated 180 degrees clockwise (at 316) from an isolating position to a vent position, so that the cam portion 246 of the second valve 66 is moved away from the third valve 70 and is positioned adjacent the notch 234 of the first valve 62. The notch 250 of the second valve 66 is then presented to the third valve 70. As shown in
With the cam portion 246 of the second valve 66 no longer blocking actuation of the third valve 70, the third valve 70 is rotated 90 degrees clockwise (at 320) from an open position to a closed position. As shown in
The above described HIPPS manifold 50 meets the Safety Integrity Level (SIL) 2 standard if used alone, the SIL 3 standard if used with two manifolds 50 in series, and the SIL 4 standard if used in a three-valve arrangement (e.g., as shown in
Conventional HIPPS manifolds utilize needle valve technology. Some embodiments of the invention provide an easier to use and more robust valve type (e.g., ball valves). The ball valves provide a larger flow path to the pressure transmitters, a more reliable and robust structure, and an easier to actuate system. The ball valves can also be arranged to match piping class specifications with a fully roddable design for ease of maintenance.
Conventional HIPPS installations 10 include a slide selector or track selector system that allows only one HIPPS manifold to be isolated (i.e., moved to the closed position as shown in
Alternatively, the HIPPS installation (e.g., installation 267 of
The cams 174, 194, 210 and the corresponding handles 178, 198, 214 are welded together. In other embodiments, the handles may be separate from the cams.
It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. Various features and advantages of the invention are set fourth in the following claims.
This application claims the benefit of U.S. Provisional Patent Application No. 61/785,472 filed on Mar. 14, 2013, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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61785472 | Mar 2013 | US |