Pump knowledge: According to the principle of pump selection, the use of reasonable pump selection methods can extend the service life of pump products, improve pump efficiency and reduce energy consumption. Eventually achieve the purpose of economy, high efficiency and energy saving.

The principle of pump selection: economy, high efficiency and energy saving

1. Economic principle: According to the specific gravity, viscosity, corrosion and other characteristics of the medium, choose the most appropriate pump material and the most suitable pump type, so as to ensure the service life of the pump.

2. High-efficiency principle: try to choose high-efficiency pumps, and use large pumps when the performance parameters are also suitable, because large pumps are more efficient than small pumps.

3. Energy-saving principle: Try to make the pump be used at or near the rated working condition, so as to improve the operation efficiency of the pump. In addition, the situation when the pumps work together should be fully considered, and the pump should be kept as efficient as possible in various situations.

Pump selection method (steps):

1. List the basic data:

1. Characteristics of medium: medium name, specific gravity, viscosity, corrosiveness, toxicity, etc.

2. What is the diameter and content of the particles contained in the medium?

3. Medium temperature

4. The required flow

5. Pressure: suction tank pressure, discharge tank pressure, pressure drop in the piping system (lift loss).

2. Determine the flow and head:

1. The flow rate is one of the important performance data of the pump selection, which is directly related to the production capacity and delivery capacity of the entire device. For example, in the process design of the design institute, the normal, minimum and maximum flow rates of the pump can be calculated. When selecting a pump, the maximum flow rate is taken as the basis and the normal flow rate is taken into account. When there is no maximum flow rate, 1.1 times the normal flow rate can usually be taken as the maximum flow rate.

2. The required head of the device system is another important performance data for pump selection. Generally, the head is selected by amplifying the 5%-10% margin to select the type.

3. Determine the material of the pump:

1. The material of the pump must meet the requirements of the characteristics of the medium: liquid properties, including the name of the liquid medium, physical properties, chemical properties and other properties. Physical properties include temperature c density d, viscosity u, solid particle diameter and gas content in the medium, etc. This involves the system head, effective cavitation allowance calculation and the type of suitable pump; chemical properties, mainly refers to the chemistry of the liquid medium Corrosion and toxicity are important basis for choosing pump material and shaft seal type.

4. Determine the type of pump:

1. According to the arrangement of the device, terrain conditions, water level conditions, operating conditions, determine the choice of horizontal, vertical and other types (pipeline, submersible, submerged, non-clogging, self-priming, gear, etc.) Pump.

2. According to the nature of the liquid medium, determine whether the clean water pump, hot water pump, oil pump, chemical pump, corrosion-resistant pump or impurity pump, or non-clogging pump is used. The pump installed in the explosion area should adopt the corresponding explosion-proof motor according to the grade of the explosion area.

3. According to the flow rate, determine whether to choose a single-suction pump or a double-suction pump; according to the head height, choose a single-stage pump or a multi-stage pump, a high-speed pump or a low-speed pump (air conditioning pump), and the multi-stage pump is less efficient than a single-stage pump, such as When the single-stage pump and the multi-stage pump can also be used, first select the single-stage pump.