Talk:Safety valve

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A temperature relief valve is not something with which I am familiar. I ask an Engineer to comment but it seems to me the only way a valve could relieve temperature would be as a consequence of the reduction of pressure. Ideal Gas Law. So it is just a pressure relief valve: The temperature and pressure relief valve mentioned in the article maybe doesn't exist? Thermostat is to temperature as relief valve is to pressure?? Anyway: please help out here! Psb777 08:30, 30 Jan 2004 (UTC)

A google search shows the term to be common. However the context seems to be that "a pressure rise (due to a temperature rise) is vented by the operation of such a valve". Elde 05:41, 1 Feb 2004 (UTC)

- I had never heard of temperature and pressure relieve valves before (even though I've personally seen safety valves at an oil refinery). Here [1] I found info about one of those. Characteristic is that these valves are equipped with a temperature sensor. Ordinary pressure relief valves open when a preset pressure is reached. Temperature and pressure relieve valves open when a preset pressure is reached. The aim of both types is the same: prevention of overpressure, but the working principle is different. Johan Lont, 194.149.80.4 10:06, 4 Jun 2004 (UTC)
This is a source for more information: www.valve-world.net

[edit] Safety Valve vs. Pressure Relief Valve

A safety valve, as described in steam engineering, will relieve excess pressure and a further pressure reduction of aprox 6% below the pressure that it popped at.

A pressure relief valve will release only the excess pressure and bring the system pressure down to popping pressure until the excess pressure condition is reduced.

It could be said that although the condition causing excess pressure in a system could still be there, a safety valve will close because of the blow down and may again open up causing cycling of the valve. If the excess pressure condition still exists with a pressure relief valve, it will not cycle like a safety valve but will stay open until the excess pressure condition is changed to reduce the system pressure.

A safety valve must be pressure, temperature and flow rated for the application (or any combination of safety valves on the system). In other words a safety valve, or valves if more than one is used to control the unsafe pressure condition, must be able to expell all gas or vapour the system is capable of producing. —The preceding unsigned comment was added by 204.19.151.8 (talk) 19:08, 30 April 2007 (UTC).