The liquid being pumped goes through the pump head, entering through an inlet line and leaving through an outlet line. An engineer, designer, or user should ensure that the pressure and temperature ratings and wetted pump materials are compatible for the application and the type of liquid being pumped. A single-piston pump delivers liquid to the outlet only during the discharge stroke. To prevent this type of “vapor lock”, chromatography solvents are often degassed before pumping.Metering Pump SchematicIf the pressure at the outlet is lower than the pressure at the inlet and remains that way in spite of the pumping, then this pressure difference opens both check valves simultaneously and the liquid flows through the pump head uncontrollably from inlet to outlet. The term “metering pump” is based on the application or use rather than the exact kind of pump used, although a couple types of pumps are far more suitable than most other types of pumps. Sometimes, a metering or similar pump has to be primed before operation, i. When gas bubbles enter a pump head, the compression motion compresses the gas but has a hard time forcing it out of the pump head. For this reason, if there is any stop valve downstream of the pump, هد دوزینگ پمپ a pressure relief valve should be placed in between to prevent overpressuring of the tubing or piping line in case the stop valve is inadvertently shut while the pump is running. The relief valve setting should be below the maximum pressure rating that the piping, tubing, or any other components there could withstand. Accessories Examples of common metering pump accessories include foot valves, pressure control valves, injection valves, inline pressure relief valves, calibration cylinders, and pulsation dampeners. Many metering pumps are rated to be able to pump into a high discharge pressure. Gases are much more compressible. Liquids are only very slightly compressible. Although metering pumps can pump water, they are often used to pump chemicals, solutions, or other liquids. The maximum pressure rating of a metering pump is actually the top of the discharge pressure range the pump is guaranteed to pump against at a reasonably controllable flow rate. The inlet valve allows flow from the inlet line to the piston chamber, but not in the reverse direction. Some single-piston pumps may have a constant slow piston motion for discharge and a quick retract motion for refilling the pump head. The liquid does not penetrate through the diaphragm, so the liquid inside the pump is sealed off from the outside. درصورتیکه شما این مقاله آموزنده را دوست داشتید و می خواهید دیتاها بیشتری در مورد خریدار دوزینگ پمپ لطفا از وبسایت ما دیدن کنید.