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Basic knowledge of chemical pumps

Time: 2017-08-18

How to choose the most suitable pump has always been something of great concern to people. It's never easy for you to choose a right chemical pump since all these factors matter: occasion, media, material, etc.

We have here the most detailed introduction of different types of pumps, so as to give you a clear impression of what kind of chemical pump you should choose.

chemical pump

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To choose a pump, we must first understand and master the principles of chemical pump selection. 

1. The selected pump type and performance in line with the device flow, head, pressure, temperature, cavitation flow, suction and other process parameters.

2. Must clarify the requirements of medium characteristics.

On the transport of flammable, explosive toxic or expensive media pump, requires a reliable seal or the use of leak-free pumps, such as magnetic drive pump, diaphragm pump, shield pump.

3. The transmission of corrosive media pump,mechanical reliability, low noise, vibration.

4. The economy should take into account the cost of equipment, operating costs, maintenance and management costs the lowest total cost.

5. Common occasions, chemical pump selection:

(1) centrifugal pump with high speed, small size, light weight, high efficiency, large flow, simple structure, no pulsation of the infusion, stable performance, easy operation and easy maintenance and so on.

(2) There are measurement requirements, the choice of metering pump.

(3) Head requirements are very high, the flow is small and no suitable small flow high-lift centrifugal motor pump can be used, the optional reciprocating pump, such as cavitation requirements are not high can also use vortex pump.

(4) Head is very low, large flow, the choice of axial flow pump and mixed flow pump.

(5) Medium viscosity (greater than 650 ~ 1000mm2 / s), consider the choice of rotor pump or reciprocating pump (gear pump, screw pump)

(6) Medium gas content of 75%, flow rate is small and the viscosity is less than 37.4mm2 / s, the choice of vortex pump.

The start of frequent or irrigation pump inconvenience occasions, should use self-priming performance of the pump, such as self-priming centrifugal pump, self-priming vortex pump, pneumatic (electric) dedicated pump.

self-priming vortex pump

Seeking convection parts using corrosion-resistant material pump selection based on the process should be based on water supply and drainage requirements, from five aspects to be considered. 

 

1. Flow is one of the important performance data of the pump, it is directly related to the production capacity and transmission capacity of the whole device. Such as the Design Institute process design can calculate the pump normal, minimum, maximum three kinds of traffic. Select the pump, the maximum flow as the basis, taking into account the normal flow, in the absence of maximum flow, it is usually desirable 1.1 times the normal flow as the maximum flow.

 

2. Device system is required to lift the pump is another important performance data, the general use of amplification 5% -10% margin to head after selection.

 

3. Liquid properties, including liquid medium name, physical properties, chemical properties and other properties, which relates to the system head, effective NPS calculation and the appropriate type of pump, pump material selection and use that kind of shaft seal type .

 

4. The piping arrangement condition of the installation system refers to the height of the liquid feeding, the distance of the liquid sending, the minimum liquid level of the suction side, the maximum liquid level of the discharge side, etc., and the specifications, lengths, materials, And so on, in order to carry on the comb head calculation and the NPSH check.

 

5. Determination of operating conditions, such as liquid operating T saturated vapor pressure, suction side pressure (absolute), discharge side vessel pressure, altitude, ambient temperature operation is gap or continuous, whether the pump position is fixed or movable of. Are an important basis for selection. Materials such as AFB stainless steel corrosion-resistant pump, CQF engineering plastic magnetic drive pump.

For the transmission of solid particles containing the media, the use of convective components required wear-resistant materials, if necessary, shaft seal with a clean liquid rinse.

magnetic drive pump

 

 

 

 

 

 

 

 

 

 

 

 

 

Pipeline arrangement of chemical pumps

In the design layout pipeline, should note the following:

 

A. Reasonable choice of pipe diameter, pipe diameter, at the same flow rate, the flow velocity is small, the resistance loss is small, but the price is high, the pipe diameter is small, will lead to a sharp increase in resistance loss, the pump head increases With the increase in power, costs and operating costs have increased. So should be considered from the technical and economic point of view.

 

B. Exhaust pipe and its fittings should be able to bear in mind the maximum pressure.

 

C. pipe layout should be arranged as straight as possible to minimize the pipe fittings and to minimize the length of the pipe must be turned when the bending radius of the elbow pipe diameter should be 3 to 5 times the angle as much as possible more than 90 Lt; 0 & gt; C.

 

D. The discharge side of the pump must be equipped with valves (ball or globe valve, etc.) and check valve. The valve is used to adjust the operating point of the pump. The check valve prevents the pump from reversing when the liquid is backflow and prevents the pump from hitting the water hammer. (When the liquid backflow, it will have a huge reverse pressure, the pump damage).

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