Beijing Institute of Chemical Technology Wu Guoxi First, the importance of regulating valve fire prevention In chemical, petroleum and other automation systems, in the event of a fire, if some of the equipment in the system can promptly cut off flammable fluid to the fire environment, then Can prevent the fire from spreading directly from the fire area to the plant area caused by a significant loss. Control valves are an important part of an automation system that is installed on-site to control the flow path so that it is the primary device that cuts off the flow path to prevent the flammable fluid from reaching the fire when it is ignited. It is crucial that it is on or off in the event of a fire. Since the regulator is controlled by the regulator in the control room and is not manually operated, the main features of the fire damper should be: to withstand short-term operation when tempered, or to minimize leakage when it is time to close. Valve fire resistance should be seen as a very desirable performance to consider, hoping to arouse the attention of the personnel concerned. Second, the standard valve fire What kind of valve is the fire valve? Foreign referred to the fire-resistant valve (fire-safe valve), the definition of foreign fire on the valve a lot of non-uniform, this definition is still lacking in the industry clearly defined. To date, there is still no single test or definition that clearly identifies whether a valve is fire proof. Many industrial societies, oil companies, insurance companies, valve manufacturers, and relevant agencies in the United Kingdom and the United States already have various test methods. However, the type of test valve and the main test specifications vary with the test method. The debate over combustion valve tests continues, with some trying to combine two or more methods into one complete method, but still not conclusive. How to accurately define the fire protection valve? This is exactly the problem we are going to study. First, we should study the problem of valve seat standard. Some people think that in the fire will not melt the metal gate valve and globe valve (globe valve) is a fire damper. These valves are designed and constructed to ensure that they are metal-to-metal contact both before and after the fire, thus preventing flammable fluids from entering the fire. However, when the metal seat is operated before the fire, the sealing property is not good. Due to the small amount of leakage, it is also permitted in most fire protection standards that have been developed. Users require the valve in normal operation both good sealing, but also has fire resistance. Many valve manufacturers tried to solve this complex problem as early as 15 to 20 years ago and they have developed a wide variety of "soft" "hard" sealing elements, all of which can hold metal surfaces Seal of contact. Hard seat is made of metal or alloy, itself can withstand high temperatures. Soft seat rubber, plastic or melting point below 700?