Pumps cannot be classified by their working principle and application in a comprehensive way, as this would lead to confusion. Application refers to the use, while principle refers to the mechanism. Pumps with different principles can be used for the same purpose. The same type of pump can also be used in different places and for different purposes. For example, a mixed-flow pump is a type of mixed-flow pump that uses a mixed-flow impeller, where the direction of the liquid flowing out of the impeller is inclined to the axis. In an axial-flow pump, the direction of the liquid flow is parallel to the axis. Important classifications include sewage pumps, chemical pumps, magnetic pumps, oil pumps, fire pumps, vacuum pumps, diaphragm pumps, screw pumps, pipeline pumps, submersible pumps, reciprocating pumps, colloid mills, water supply and drainage equipment, hydraulic injectors, control cabinets, etc. Several types are listed below for reference:
1. First, the main categories are classified according to the working principle:
1) Blade pumps
Blade pumps can be divided into: centrifugal pumps, mixed-flow pumps, axial-flow pumps, and vortex pumps.
Centrifugal pumps can be further divided into single-stage pumps and multi-stage pumps.
Single-stage pumps can be divided into: single-suction pumps, double-suction pumps, self-priming pumps, and non-self-priming pumps, etc.
Multi-stage pumps can be divided into: segmented type and volute type.
Mixed-flow pumps can be divided into volute type and guide vane type.
Axial-flow pumps can be divided into fixed blade and adjustable blade.
Vortex pumps can also be divided into single-suction pumps, double-suction pumps, self-priming pumps, non-self-priming pumps, etc., submersible pumps.
2) Positive displacement pumps
Positive displacement pumps can be divided into reciprocating pumps and rotary pumps.
Positive displacement pumps rely on the working components reciprocating or rotating in the pump cylinder to alternately increase and decrease the working volume, thus achieving the suction and discharge of liquid. Positive displacement pumps whose working components reciprocate are called reciprocating pumps, and those whose working components rotate are called rotary pumps. The suction and discharge processes of the former alternately take place in the same pump cylinder and are controlled by suction valves and discharge valves; the latter uses the rotation of working components such as gears, screws, vane rotors, or vanes to force the liquid to transfer from the suction side to the discharge side, sewage pump.
The flow rate of a positive displacement pump at a certain speed or reciprocating frequency is constant and hardly changes with pressure; the flow rate and pressure of a reciprocating pump have large pulsations, and corresponding pulsation reduction methods are needed; rotary pumps generally have no pulsation or only small pulsation, diaphragm pump; it has self-priming capability, centrifugal pump; it can remove air from the pipeline and suck in liquid after the pump starts; when starting the pump, the discharge pipeline valve must be fully opened; reciprocating pumps are suitable for high pressure and small flow rate; rotary pumps are suitable for medium and small flow rate and higher pressure; reciprocating pumps are suitable for transporting clean liquids or gas-liquid mixtures, chemical pumps. In general, the efficiency of positive displacement pumps is higher than that of dynamic pumps.
3) Jet pumps
It relies on the high-speed jet of the working fluid to induce the fluid, and then increases the energy of the induced fluid through momentum exchange.
Dynamic pumps rely on the force of a rapidly rotating impeller on the liquid to transfer mechanical energy to the liquid, increasing its kinetic energy and pressure energy, and then converting most of the kinetic energy into pressure energy through the pump cylinder to achieve transportation. Dynamic pumps are also called centrifugal pumps or blade pumps.
Centrifugal pumps are the most common type of dynamic pump.
The head generated by a dynamic pump at a certain speed has a limited value, magnetic pump; the head changes with the flow rate; the operation is stable, self-priming pump; the transportation is continuous, and the flow rate and pressure have no pulsation; it generally has no self-priming capability and needs to be filled with liquid or the pipeline needs to be vacuumed before starting operation, water pump; it has a wide range of practical applications; it is suitable for transporting clean liquids with very low viscosity, and specially designed pumps can transport slurry, sewage, etc., or water-carrying solids. Dynamic pumps are mainly used for water supply, drainage, irrigation, process liquid transportation, power plant energy storage, hydraulic transmission, and ship jet propulsion, etc.
4) Other classifications of pumps
In addition to being classified by working principle, pumps can also be classified and named in other ways. For example, according to the driving method, they can be divided into electric pumps, steam turbine pumps, diesel pumps, and hydraulic pumps; according to the structure, they can be divided into single-stage pumps and multi-stage pumps; according to the application, they can be divided into boiler feed pumps and metering pumps; according to the nature of the transported liquid, they can be divided into water pumps, oil pumps, and slurry pumps, etc.
