Back pressure valve pressure can be adjusted generally. The most commonly used system, fluid metering system, hydraulic control system, chemical reaction conditions, state critical state control. Basic can be divided into two parts of regulation and over-current. Back pressure valve through the built-in spring elastic force to achieve action: When the system pressure is lower than the set pressure, the diaphragm in the spring force to block the pipeline; when the system pressure is greater than the set pressure, the diaphragm compression spring, the pipeline Connected, liquid through the back pressure valve. Backpressure valves maintain the pressure required on the line in the event of a pressure build-up on the line or in the equipment container, allowing the pump to deliver flow normally. The other end of the pump due to gravity or other functions often appear siphon phenomenon, then the back pressure valve can reduce the siphon flow and pressure fluctuations. For metering pumps and other volumetric pumps operating under low system pressure, there will be excessive delivery. In order to prevent similar problems, it is necessary to make the inlet and outlet of the metering pump have a back pressure of at least 0.7 Bar, generally, the back pressure valve is installed at the outlet of the metering pump to achieve the purpose. 1. The check valve in the outlet pipe is used to prevent backflow of the liquid and the back pressure valve is used to keep the pump outlet at a constant pressure. 2. Used in combination with the pulsation damper to reduce the damage of the water hammer to the system and reduce the peak value of the flow velocity fluctuation , To protect the piping, elbows, joints from the impact of pressure fluctuations; 3. For the metering pump to create a good working environment and improve the performance of the pump; 4. To ensure the stability of the pump outlet flow, such as the flow of some pumps with Pressure changes larger, the pump outlet can be set back pressure valve, the pump output flow stability, then the general choice of back pressure valve pressure for the actual use of the pump pressure or slightly less than the pressure of the pump; 5. In the tube Road or equipment containers under pressure instability, the pipeline can maintain the pressure required to enable the pump output flow; 6. In the pump outlet due to gravity or other effects often appear gravity or siphon phenomenon, the back pressure valve can be reduced Due to the siphon flow and pressure fluctuations, this time generally greater than the pressure of the liquid itself can be used, such as to prevent the liquid level of 2 meters medicine tank gravity, the pressure can be greater than the back pressure of 0.02MPa Valve, the general choice of 0.1MPa can be. The fluid enters through the back pressure valve inlet and is blocked by the diaphragm, whereupon fluid exerts upward pressure on the diaphragm. When the pressure is large enough, the spring is compressed, the fluid from the diaphragm to form a channel from the back pressure valve outlet; if the fluid pressure is not enough, it will form a pressure, the inlet pressure rise until it reaches the rated pressure, jacking up the diaphragm path. Back pressure valve rated pressure adjustable, generally by adjusting the top of the spring rod, which adjust the length of the spring to achieve. In the outlet line, the backpressure valve should be used with a pulsation damper to absorb the peak flow between the pump and the backpressure valve with a pulsation damper. Without a pulsation damper, the backpressure valve will open and close quickly with each pump stroke. With a pulsation damper, the backpressure valve will oscillate in the half-open and half-off positions so that the pulsation damper reduces back wear. For large flow pumps, and the outlet pipe is long and thin, back pressure valve should be installed near the filling point to reduce the tendency of siphon. When transporting media containing suspended solids, install a tee (or four-way) with pipe plug at the inlet of the backpressure valve to allow the pipe to be cleaned without disassembly. Backpressure valves are just one type of piping component that works best with other piping components, such as pulsation dampers, safety valves, check valves, and shut-off valves. 1, the required diameter of the back pressure valve, usually the diameter of the pump outlet; 2, what material is needed, this is generally considered from the nature and temperature of the fluid delivered. Conventional materials are: PVC, 304,316,316 L stainless steel, carbon steel, there are special requirements generally available to manufacturers order; 3, import and export connections, the less general requirements. However, in some systems, such as food and beverage systems, some piping may have special requirements for the connection method. Common connection with internal thread, flange, hose connector; 4, the installation should avoid resonance with the system, otherwise it will have a serious impact on the back pressure valve work and may damage the back pressure valve dangerous; 5, and pulsation damper At the same time, the pulsation damper should be placed between the pump and the back pressure valve to absorb the peak flow between the pump and the back pressure valve. Slow down the back pressure valve wear speed; 6, outdoor use should be added protective shed or protective cover; 7, the back pressure valve for any maintenance before the operation should stop the equipment, release the pressure to close the back pressure valve system associated with the valve, Also confirm that there is no pressure in the pulsation damper. Maintenance attention to prevent liquid being transported to harm the human body; 8, back pressure valve with directionality. If the back pressure valve inlet and outlet reverse, back pressure will be doubled, to bring harm to the system and may be dangerous; 9, operating back pressure valve failure should promptly stop the system or shut down the back pressure valve where the pipeline , Stop the use of back pressure valve, and check replacement back pressure valve; 10, the back pressure valve for any inspection, maintenance, should stop running equipment, release valve pressure, close the back pressure valve and system associated valve, at the same time Make sure there is no pressure in the pulsation damper. Maintenance attention to prevent high-pressure fluid valve splash, hurt the human body.
