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Selection of metering Pump parts precautions

Edit:Huaian Machinery Co., Ltd.UpDate:2018-08-02

The rational selection of metering pump parts reply.Metering Pump AccessoriesVarieties include metering pump pump head, metering pump one-way valve, one-way valve valve ball and sealed ball seat, metering pump and metering pump hose connector. The article mainly from the selection of these parts to consider which questions to be answered. Since we all attach importance to the selection of metering pumps, some of the common sense does include some of the key, while others neglect the importance of the details to determine the winning or losing.

1, metering pump head: The important consideration of its raw material problems, general selection of general-purpose metering pump pump head raw materials: Pp,pvc,ptfe and SS316. PP: Simple molding, low cost, acid and a certain degree of resistance to high temperature talent; but not suitable for organic solvents, strong acids and alkalis and liquids containing hypochlorite. The concentration is limited. PVC: Simple molding, low cost, acid and alkali, but not suitable for organic solvents, strong acid and alkali and more than 40 ℃ liquid metering, inappropriate food and drinking water industry, toxic, food packaging bags no longer use PVC bags. PTFE: Suitable for all kinds of media, high temperature resistance, but difficult to form, high cost; SS316: suitable organic solvents and high temperature liquids, but not resistant to strong acids.

2, the separation of the metering pump selection: Common barriers: composite barriers and pure PTFE barrier; Compound barrier: NBR rubber with internal bolts The outer surface is coated with a layer of PTFE film to form a composite barrier, and some in the rubber barrier is also inlaid with a wire mesh to add its strength. The cost of this barrier is low, the elastic deformation is large, can produce the larger flow from the small plane scale, make the power of electromagnet reduce, decrease the production cost. But in the long run, the heat of the electromagnet will pass through the radiation and its mounting bolts to accumulate on the rubber surface, coupled with deformation, the gap will quickly aging and breakage, so the type of barrier metering pump has a gap broken indicator hole.

Pure PTFE Barrier: The completion of the modified PTFE processing, the cost is relatively high, the gap deformation is relatively small, but it can never damage. Italy's metering pump on the market for pure PTFE barrier, the other manufacturers are more complex barrier.

3, metering pump check valve: Taking into account the internal structure, one-way valve's non-return structure: Gravity Check back and elastic check back; Gravity Check back: Valve ball on its own component back sealing surface, forming a one-way check structure, good sealing effect, high pressure resistance. Elastic Check back: The elasticity of the rubber itself back to its return status, low cost, high pressure, long-term operation, rubber aging, the effect of the check back, other acid and alkali corrosion will make its structure deformation, deterioration of the back effect. Italian-made metering pumps on the market are mostly elastic check-back structure, the United States, Germany and Japan metering pump for gravity check-back structure.

4, the gravity check structure of the one-way valve valve ball and sealed ball seat; Common valve ball material two kinds: glass ball and ceramic ball; glass ball: low cost, but some of the acid and alkali ions will form corrosion; ceramic ball: high cost, but suitable for all kinds of acid and alkali; universal sealing ball seat: General plastic ball seat, rubber ball seat and PTFE ball seat. General Plastic ball SEAT: The cost is low, some media will corrode to it, long-term operation after the return effect becomes worse. Rubber ball Seat: Low cost, long-term acid and alkali corrosion will change its shape, the return effect is poor or blocked over-flow channel. (generally found in the market normal metering pump operation for a period of time after the phenomenon is caused by the liquid) PTFE ball seat: High cost, suitable for a variety of liquids and never deformation.

5, how to select the metering pump hose connector? Hose Connector Raw MATERIALS: general plastic and PTFE electromagnetic barrier metering pump flow is generally relatively small, the inner diameter of its hose is relatively small, which makes the wall thickness of the hose connector also become very thin (in order to ensure that the fluid pass through, so that the internal hole of the connector can not be too small). Long-term acid and alkali media scouring, general plastic joints are simple corrosion cracking, resulting in hose junction leaks, and PTFE joints to eliminate the occurrence of this condition.

Total consideration of the overall factor of the metering pump is available, the selection should be noted two parameters: flow and pressure, the pressure on the label is the highest normal working pressure of the metering pump, the flow is the larger flow under this pressure. Metering pump is a one-way displacement pump, the pressure in the pump cavity is greater than the outside pressure when the metering pump ability to play liquid. When external pressure is higher than the pressure on the sign, the metering pump works in an overloaded condition. If it is the electromagnetic barrier metering pump, its flow will drop a lot, and even can not make liquid, if it is motor-driven metering pump, the motor may be overheating damage. All of the above for the Anhui Secco Environmental protection technology to pick up. Welcome to checkMetering pumpProducts.