In order to prevent the leakage or media backflow after the failure of the check valve, which may cause a decrease in product quality and cause adverse consequences such as accidents, one or two shut-off valves are installed before and after the check valve. If two shut-off valves are installed, it can be convenient to disassemble and repair the check valve.
Protective facilities for safety valves
Before and after installation, isolation valves are generally not installed, and can only be used in individual cases. If the medium force contains solid particles that affect the safety valve's ability to close tightly after takeoff, a gate valve with a lead seal should be installed before and after the safety valve. The gate valve should be in a fully open state, and a DN20 inspection valve should be installed directly to the atmosphere for both the gate valve and the safety valve.
When the released wax and other media are in a solid state at room temperature, or when the temperature of light liquid and other media is lower than 0 degrees Celsius due to pressure reduction gasification, the safety valve needs steam heating. For safety valves used in corrosive media, depending on the corrosion resistance of the valve, consider adding a corrosion-resistant explosion-proof film at the valve inlet. A gas safety valve is usually equipped with a bypass valve according to its diameter, which is used for manual venting.
Protective facilities for pressure reducing valves
There are generally three types of installation facilities for pressure reducing valves. Pressure gauges are installed before and after the pressure reducing valve, making it easy to observe the pressure before and after the valve. There is also a fully enclosed safety valve installed behind the valve to prevent it from jumping when the pressure behind the valve exceeds the normal pressure after the pressure reducing valve fails, including the system behind the valve. The drainage pipe is installed in front of the shut-off valve in front of the valve, mainly for drainage and river flushing, and some use drain valves. The main function of the bypass pipe is to close the shut-off valves in front and behind the pressure reducing valve when the pressure reducing valve malfunctions, open the bypass valve, manually adjust the flow rate, and play a temporary circulation role for maintenance or replacement of the pressure reducing valve.
Protective facilities for steam traps
There are two types of traps with or without a bypass pipe on the side, including condensate recovery and non recovery payment. For traps with a drainage capacity of up to and other special requirements, they can be installed in parallel.
A drain valve with a bypass valve is mainly used to discharge a large amount of condensed water when the pipeline starts running. It is not appropriate to use a bypass pipe to discharge condensate when repairing the drain valve, as this can cause steam to flow into the return water system. In general, a bypass pipe may not be installed. Only heating equipment with strict requirements for heating temperature can be equipped with bypass pipes for continuous production.
