The Layout of Safety Valves
Safety valves are best overpressure protection devices on pressure equipments, containers and pipelines. When medium pressure exceeds the allowable value, the valve will open and discharge automatically to prevent the rising pressure, so that the safety of the equipments and operation personnel can be guaranteed. On the contrary, when the pressure is reduced to a predetermined value, the valve will automatically close to prevent the media continue to drain and reduce losses. Since safety valves are automatic valves, they are often treated as the last protection device for pressure equipments. In this sense, the role of safety valves can not be replaced by other protective devices.
Safety valves should be installed vertically and get close enough to the protected equipments or pipelines. If the valve can not near them, then the total pressure from the protected equipments or pipeline to the outlet of safety valves should not exceeds 3% of the predetermined value or 1/3 of the maximum allowable blowdown (whichever is the smaller prevail). During engineering practice, there are several ways to reduce the pressure of pipelines, such as expanding the inlet diameter of safety valves appropriately, using long-radius elbows, decreasing the number of elbows and so on to reduce the total pressure of pipelines.
Easy maintenance should be the main consideration when installing a safety valve. Therefore, there should be a maintenance platform so that people can easily piping and also do regular inspection, maintenance and calibration work. When installing safety valves with large weight, you need to take the hoisting into consideration after disassembling. If necessary, setting up a boom or leaving the space for inspection and maintenance is required. During engineering practice, the common practice is installing safety valves in the pipe gallery top to make the repair and maintenance convenient.
Due to some special reasons, it is difficult to install the valve on the container body. Therefore, installing safety valves on the outlet of pipeline could be taken into the consideration, but you need to pay attention to the joint structure so as to prevent an increase in pipeline resistance and the accumulation of dirt clogging and other circumstances.