Select the metering pump parts noteMetering pump parts selection of answers. Metering pump parts include metering pump, metering pump check valve, check valve sealing ball valve ball and seat, metering pump diaphragm metering pump and hose connector. Articles from these components to consider when selecting which questions are to be answered. Because everyone focused on metering pump selection requirements, some knowledge does cover some of the points but others ignored the importance of detail selection decision success or failure.
1, the metering pump head: important considerations of the material problems, generally used common metering pump material: PP,PVC,PTFE and SS316. PP: easy, low cost, acid resistance and some degree of heat; but not for organic solvents, strong acid and hypochlorite-containing liquids. A limited concentration. PVC: easy, low cost, acid, but not for organic solvents, strong acids alkalis and above 40 ° c measurement of liquid, not suitable for food and drinking water, toxic, food packaging bags PVC bag. PTFE: for a variety of media, high temperature resistance, but forming, high cost of SS316: suitable for organic solvents and hot liquids, but not resistant to strong acids.
2, the diaphragm metering pump selection: diaphragm: pure PTFE composite diaphragm and diaphragm composite diaphragm: Insert bolts in the NBR pasting a layer on the surface of the rubber diaphragm PTFE thin film composite membrane is made, embedded in rubber diaphragm of steel wire net to increase its strength. This diaphragm low cost elastic deformation, flow can produce larger sizes by smaller planes, the electromagnet of power is reduced, reducing production costs. But when the long-running, electro-magnet of the accumulation of heat through radiation and conduction of the inlaid bolt on to the rubber surface and deformation, the diaphragm is quickly aging damage, indicating whether the type diaphragm metering pumps are diaphragm damaged hole.
pure PTFE diaphragm: completed by modification of PTFE as a whole, relatively high cost, divide the amount is relatively small, but it can never be damaged. Market Italy pure PTFE diaphragm metering pumps for, others are composite diaphragm.
3, metering pump check valve: taking into account the internal structure of a one-way check valve structure: gravitational and elastic return; gravity check valve sealing surface of the weight of the ball on their own returns, form a one-way check valve structure, good sealing, high pressure resistance. Elastic back: elastic recovery of rubber by itself the check status, low cost, no pressure, after a long run, rubber, check the effect becomes worse, acid and alkali corrosion will make its structure, deterioration of check results. Market Italy produces more metering pumps are flexible back structure, United States, Germany, and Japan produced the metering pump is gravity check structure.
4, and gravity check back structure of one-way valve of valve ball and the sealed ball seat; General of valve ball material two species: glass ball and ceramic ball; glass ball: cost low, but part acid alkali within of ion will on its caused corrosion; ceramic ball: cost high, but for various acid alkali; General of sealed ball seat: General plastic ball seat, rubber ball seat and the PTFE ball seat. Common plastic tee: low cost, some of the medium the corrosion, back after a long run effect becomes worse. Rubber balls: low cost, acid and alkali corrosion will change its shape for a long time, check the effect becomes weak or blocked flow channel. (Usually found on the market after a period of normal pump operation is not the liquid resulting from) PTFE balls seat: high cost, suitable for all kinds of liquid and never deformation.
5, how to select metering pump hose connector? Hose material: plastics and PTFE of electromagnetic diaphragm metering pump flow rate is usually relatively small, so the internal diameter of the hose is relatively small, which makes the hose wall thickness also becomes very thin (in order to ensure fluid path, making joints in the hole too small). Long scoured by acid and alkaline media, ordinary plastic joints can easily be corrosion cracking, cause leaks hose connections, while PTFE joint prevents this from happening.
total consideration to metering pump elements available, selection to the attention of two parameters: flow and pressure, signs the pressure is the pump maximum working pressure, the flow is under the pressure of the maximum flow. Metering pump is a one-way volumetric pump, the pressure in the pump Chamber is higher than outside pressure metering pumps and get liquid. When the external pressure is higher than the signs of stress, metering pump in overload. If the electromagnetic diaphragm metering pump, flow will drop a lot, not even the liquids; if it is a motor-driven metering pumps, motor damage due to possible overheating. Above all-Secco in Anhui Province environmental protection science and technology together. Metering pumps welcome products.