When the valve is installed, in order to keep metal, sand and other foreign matter from invading the valve and damaging the sealing surface, it is necessary to set a filter and a flush valve; in order to keep the compressed air clean, an oil-water separator or an air filter needs to be set before the valve; Considering that the working status of the valve can be checked during operation, it is necessary to set up instruments and inspection valves; in order to maintain the operating temperature, set up insulation facilities outside the valve; for the installation behind the valve, it is necessary to set up a safety valve or a check valve; considering the continuous operation of the valve , to facilitate the danger, set up a parallel system or bypass system.
1. Protective facilities for check valve
In order to prevent the leakage of the check valve or the back-flow of the medium after the failure, which will cause the decline of 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 provided, the check valve can be easily removed for maintenance.
2. Protection facilities for safety valve
Generally, there is no block valve before and after the installation method, and it can be used only in individual cases. If the medium force contains solid particles, which affects that the safety valve cannot be closed tightly after it jumps, 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. DN20 check valve towards atmosphere.
When the medium such as wax to appease and discharge is in a solid state at room temperature, or when the temperature of the medium such as light liquid is lower than 0 degrees Celsius due to decompression and gasification, the safety valve needs steam tracing.
For safety valves used for corrosive media, depending on the corrosion resistance of the valve, consider adding a corrosion-resistant explosion-proof membrane at the valve inlet.
The gas safety valve is generally equipped with a bypass valve according to its diameter, which is used for manual venting.
3. Protective facilities of pressure reducing valve
There are generally three forms of pressure reducing valve installation facilities. Pressure gauges are installed before and after the pressure reducing valve, which is convenient to observe the pressure before and after the valve. There is also a fully enclosed safety valve behind the valve to prevent the valve 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 drain pipe is installed in front of the cut-off valve in front of the valve, mainly for the flushing effect of the drainage river, and some use a trap. The main function of the bypass pipe is to close the shut-off valves before and after the pressure reducing valve when the pressure reducing valve fails, open the bypass valve, manually adjust the flow, and play a temporary role in circulation, so as to repair the pressure reducing valve or replace the pressure reducing valve.
4. Protective facilities for traps
There are two types of bypass pipes and no bypass pipes on the side of the trap, with condensate recovery and condensate non-recovery payment, and the drain valve with discharge capacity and other special requirements can be installed in parallel.
The trap with bypass valve is mainly used to discharge a large amount of condensate when the pipeline starts to run. When servicing traps, it is not appropriate to use a bypass pipe to drain condensate, which will allow steam to escape into the return water system. Under normal circumstances, the bypass pipe may not be installed. Only if there are strict requirements for heating temperature, a bypass pipe should be installed in the continuous production heating equipment.
Post time: Nov-11-2022