Gear pump selection principle
1.so that the selected type and performance of gear pump device flow, head, pressure, temperature, cavitation flow, suction and other process parameters.
2.Gear pump must meet the requirements of medium characteristics. For the transmission of inflammable, explosive toxic or valuable medium gear pump, the shaft seal of gear pump is required to be reliable or adopt no leakage pump, such as magnetic drive pump, diaphragm pump, shield pump, for the transmission of corrosive medium gear pump, it is required to use corrosion resistant materials such as AFB stainless steel corrosion resistant pump and CQF engineering plastic magnetic drive pump. For Gear pump conveying solid particle medium, it is required to use wear-resistant material for convection parts and clean liquid for shaft seal when necessary.
3.gear pump mechanical aspects of high reliability, low noise, small vibration.
4. gear pump economy to take into account the equipment costs, operating costs, maintenance costs and management costs of the lowest total cost.
5. The Centrifugal pump has the characteristics of high speed, small volume, light weight, high efficiency, large flow, simple structure, no pulsation, stable performance, easy operation and convenient maintenance. Therefore, in addition to the following cases, should be as far as possible to choose centrifugal pumps: When there are metering requirements, choose metering pumps, lift requirements are very high, flow is very small and no suitable small flow high-lift centrifugal pumps can be selected, can choose reciprocating pump, such as cavitation requirements are not high can also choose the vortex pump.
The head is very low, the flow is very big, may choose the axial flow pump and the mixed flow pump.
When the medium viscosity is larger than 650 ~ 1000mm2/s, the rotor pump or the reciprocating pump (gear pump, screw pump) medium gas content 75% , the flow rate is small and the viscosity is less than 37.4mm2/s, the vortex pump can be selected.
On the occasion of frequent start or pump filling inconvenience, should choose the pump with self-priming performance, such as self-priming Centrifugal pump, self-priming vortex pump, pneumatic (electric) diaphragm pump.
gear pump selection basis
1.gear pump selection basis, should be based on the process flow, water supply and drainage requirements from five aspects to be considered, the flow rate is one of the important performance data of gear pump, which is directly related to the production capacity and delivery capacity of the whole device.Such as the design institute process design can be calculated pump normal, the smallest, the largest three kinds of flow.Select the gear pump, based on the maximum flow, taking into account the normal flow, in the absence of the maximum flow, usually can take 1.1 times the normal flow as the maximum flow.
2.The head needed by the device system is another important performance data of the gear pump, which should be selected by enlarging 5% to 10% of the residual head.
3. Liquid properties, including the name of the liquid medium, physical properties, chemical property and other properties, physical properties such as temperature c Density D, viscosity U, diameter of solid particles in the medium and gas content, etc. , which involve the head of the system, effective cavitation allowance calculation and suitable pump type: chemical property, mainly refers to the liquid medium chemical corrosion and toxicity, is the selection of pump materials and the choice of which type of shaft seal an important basis.
4.The piping layout condition of the installation system refers to some data such as the height of liquid feeding, the distance of liquid feeding from the direction of liquid feeding, the lowest liquid level on the suction side, and the highest liquid level on the discharge side, as well as the pipe specifications and their length, materials, pipe fittings specifications, quantities, etc. , in order to calculate the system carding head and check the cavitation allowance.
5.The terms of operation are many, such as liquid operation t saturated steam pressure P, suction side pressure PS (absolute) , discharge side container pressure PZ, altitude, ambient temperature operation is clearance or continuous, pump position is fixed or movable.
Post time: Oct-29-2021