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Method and system for testing safety relief valves

A method and system for testing safety relief valves utilizes a reservoir of high pressure fluid which is metered into a smaller pressure vessel in communication with the safety relief valve to be tested. The method and system permits a safety relief valve to be tested with air as well as water. A method for testing a safety relief valve comprising the steps of: (a) disposing a first pressure vessel in fluid communication with a reservoir of high pressure fluid; (b) disposing between the first pressure vessel and the reservoir, a first means for controlling the fluid flow between the first pressure vessel and the reservoir; (c) maintaining the pressure of the high pressure fluid in the reservoir at a substantially greater pressure than the pressure in the first pressure vessel; (d) disposing the safety relief valve in unrestricted fluid communication with a second pressure vessel; the second pressure vessel being disposed between the first pressure vessel and the safety relief valve, the first pressure vessel having a larger volume than the second pressure vessel; (e) disposing between the first and second pressure vessels, a second means for controlling fluid flow between the first and second pressure vessels; (f) metering high pressure fluid from the reservoir through the first and second pressure vessels and into the safety relief valve, by utilizing the fluid flow control means, to provide the necessary fluid pressure in the second pressure vessel to open the safety relief valve, and to provide a sufficient, variable volume of fluid through the safety relief valve to prevent the safety relief valve from simmering and damaging the safety relief valve upon closing. Many types of plants and manufacturing facilities, among other locations, include the use of safety relief valves which are designed to open and release excess pressure within pressure vessels and pressure lines, when the pressure therein exceeds a predetermined pressure value. Such safety relief valves can range in size from quarter inch diameter threaded valves to twelve inch diameter safety relief valves. It is of utmost importance to be able to determine at what pressure the safety relief valve does in fact open. Although such safety relief valves are engineered and designed to open at a particular pressure, commonly referred to as the set pressure, the actual pressure, or actual set pressure, at which the valve opens is frequently different. Likewise, the design pressure at which the safety relief valve is designed to reseat, or close, may be in fact different from the actual reseat pressure. In many installations wherein safety relief valves are utilized, such as nuclear power plants, it is extremely important to know at what exact pressure such safety relief valves open, rather than what the design set pressure is. The method and system for testing safety relief valves of the present invention, when compared with previously proposed prior art methods and apparatus for testing safety relief valves have the advantages of: permitting safety relief valves to be tested on the same apparatus both with air and hydrostatically; eliminates a plurality of different sized pressure vessels to be used to test different sizes of safety relief valves; provides a sufficient air volume to the safety relief valve without simmering the safety relief valve or permitting the safety relief valve seats to slam shut and damage the seats of the safety relief valve; being efficient and economical to manufacture and use; and permitting accurate measurement and recording of the actual pressure required to open and reseat the safety relief valves.

                                                                                                    Shanghai Remy Valve Manufacturing Co., Ltd

2012-01-12 05:17

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