Double seal rail valve function

1, fire prevention and sealing oil and gas storage and transportation system are flammable and explosive media. Fire prevention is a key issue in the design and selection of oil and gas storage and transportation devices. The device not only requires better sealing, but also has certain sealing performance when a fire occurs on the site. Double sealed rail valve seal forms are used soft and hard seal combination, including the valve flap and cover, chassis and other structures. Soft sealing can ensure zero leakage under normal operation. When a fire occurs in the scene, the soft sealing may be damaged. In this case, the hard sealing will play a role of main sealing to prevent large amount of leakage of the medium. In contrast, the gate valve with a hard seal, fire better, but the sealing performance is not easy to be guaranteed, long-term use is difficult to ensure zero leakage; ball valve with a soft seal, its long life, but do not have fire safety. 2, with online repair function When the valve flap on the soft seal due to some damage caused by internal leakage or manipulator (actuator) failure, the valve does not have to be removed from the pipe can be replaced or repaired, the manipulator The maintenance can also be carried out in the pipeline non-stop state. The gate valve or ball valve seal damaged, the valve must be removed from the pipeline in order to carry out maintenance or replacement, or even the valve scrapped. 3, with double shut-off and bleed function Use two cut-off valve (gate valve or ball valve) to cut off the medium, and between the two cut off valve installed a drain valve, when the cut-off valve leak occurs, the leakage of the medium Out through the drain valve, this will not result in the blending of the two media. This feature is achieved with just one valve with a dual seal rail valve, with a vent medium at the bottom of the double sealed rail valve. 4 With Cavity Pressure Relief Function AP I6 D Specification "For all double sealed valves, Medium used, it must have a pressure relief function ", the pressure relief is due to changes in ambient temperature generated. In the normally closed state, the pressure in the double seal valve chamber will increase rapidly due to the temperature increase. If the pressure difference is not released in time, the valve operation will have a serious impact. Manually operated double seal rail valves typically have the following two pressure relief systems. (1) Manual Pressure Relief System The manual pressure relief system is usually a needle valve mounted on the end cap. This type of pressure relief system can be used when the medium is a liquid that can be vented to the atmosphere in small quantities. (2) Differential Pressure Relief System Differential pressure relief system is a line system with a one-way valve. In this system, the needle valve I is normally closed, the needle valve is normally open. This type of pressure relief system (typically pressure relief in upstream piping) is required when the medium is liquid that is not vented to the atmosphere. Differential heat relief system does not require human control Only in the detection of internal leakage, only need to manually open the needle. 5, with the leak test function When the general valve is closed, the sealing effect of the test more difficult, and double sealed guide rail valve test is very easy, as long as the closure of the open pressure relief system and the cap connected to the needle The valve can be, if the valve disc leakage, the media will flow out through the needle valve. If the medium does not make it to the atmosphere, you can take a pressure gauge on the needle valve, by observing the changes in gauge pressure to determine whether the internal leakage 6, the unique pipeline decompression function Pipeline decompression is the tank area manifold In the design, the key consideration is that when the valve in the tank is closed, the pipe network is still full of media: as the ambient temperature increases, the pressure of the medium in the pipe network will increase rapidly; when the temperature difference changes greatly, Increased pressure will exceed the pipe capacity, easily lead to pipeline leakage Therefore, the pipeline should be equipped with decompression equipment, pipeline decompression design .In the main cut-off valve between the upstream and downstream pipeline decompression system, the system consists of two cut-off valve (Gate valve, ball valve or globe valve) and a pressure relief valve between the two shut-off valves. The system is costly and space-consuming, making it inconvenient for site management. The main cut-off valve adopts the design principle of the pipeline with double sealed guide rail valve. The decompression system is attached to the main cut-off valve. The design is simple in structure, takes up less space and has lower cost.

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