Regarding the selection of centrifugal pumps

Based on your process design parameters: select the pump material according to the properties of the medium to be transported (corrosion resistance/heat resistance), as well as considering the height at which the medium needs to be transported and the flow rate requirements of your process.

Selecting a pump is relatively simple; it just involves choosing one based on your process requirements (flow rate, head, medium, etc.). You can simply call a technician at a pump manufacturer, and they will guide you through the process.

I. Principles for pump selection 1. The type and performance of the selected pump must meet the requirements of process parameters such as flow rate, head, pressure, temperature, net positive suction head, and suction lift of the installation, as well as the fire safety regulations applicable to the location where the pump will be used. 2. High reliability in terms of mechanics, low noise, and minimal vibration. 3. Economically, it is necessary to take into account the total cost of equipment expenses, operating costs, maintenance costs, and management fees to minimize it. 4. Centrifugal pumps feature high speed, small size, light weight, high efficiency, large flow rate, simple structure, pulse-free fluid delivery, stable performance, ease of operation, and convenient maintenance. Therefore, except in the following cases, centrifugal pumps should be preferred whenever possible: when metering is required, metering pumps should be used. When a very high head is required, the flow rate is low, and no suitable centrifugal pump with a low flow rate but high head is available, a reciprocating pump can be used; if high resistance to cavitation is needed, a vortex pump can also be chosen. When the head is very low and the flow rate is high, axial flow pumps and mixed-flow pumps can be selected. When the medium viscosity is high (greater than 650–1000 mm2/s), a rotary pump or reciprocating pump (gear oil pump, screw pump) can be considered; when the medium contains 75% air, the flow rate is low and the viscosity is less than 37. At 4 mm2/s, an vortex pump can be selected. For applications where starting is frequent or pumping is inconvenient, pumps with self-priming capabilities should be used, such as self-priming centrifugal pumps, self-priming vortex pumps, and pneumatic (electric) diaphragm pumps. II. Criteria for Pump Selection The criteria for selecting a pump should be considered from five aspects, based on the process flow and water supply/distribution requirements: fluid flow rate, head capacity of the unit, properties of the fluid, pipeline layout, and operating conditions. 1. Flow rate is one of the important performance parameters for selecting a pump, as it is directly related to the production capacity and transfer capacity of the entire system. If the process design in the design institute can calculate the normal, minimum, and maximum flow rates of the pump. When selecting a pump, the maximum flow rate should be taken as the basis, with consideration also given to the normal flow rate; in the absence of a maximum flow rate, 1 times the normal flow rate can usually be used. 1 times as the maximum flow rate. 2. The head required by the installation system is another important performance parameter for selecting a pump; generally, the head value should be increased by 5%–10% as a margin when making the selection. 3. Properties of the liquid, including the name of the liquid medium, its physical properties, chemical properties, and other characteristics. Physical properties include temperature, density, viscosity, the diameter of solid particles present in the medium, and the gas content; these factors are relevant to calculating the system’s head, the effective net positive suction head, and determining the appropriate type of pump. Chemical properties refer mainly to the chemical corrosiveness and toxicity of the liquid medium, and they serve as important criteria for selecting the material for the pump as well as the type of shaft seal to use. 4. The pipeline layout conditions of the plant system refer to data such as the liquid delivery height, distance, and direction; the lowest liquid level on the suction side and the highest liquid level on the discharge side; as well as details regarding pipe specifications, their lengths, materials, fitting specifications, and quantities. These are needed for calculating the system head and verifying the net positive suction head. 5. There are many aspects related to operating conditions, such as the operating temperature of the liquid, the saturated vapor pressure P, the suction side pressure PS (absolute), the pressure in the discharge side container PZ, altitude, ambient temperature, whether the operation is intermittent or continuous, and whether the pump’s location is fixed or movable.

The medium in my pump is water, and it is used for a condenser with an area of 30 square meters. The condenser is located at a height of about 10 meters above the ground. I would like to ask everyone, what kind of pump would be suitable in this case?

Based on the flow rate and head you need, find a sample from a pump manufacturer and choose one from it. That’s all there is to it

It’s not that complicated. You just need to calculate the flow rate and head pressure, as well as determine what medium is being transported. Give the manufacturer a call to ask them; those who work on water pumps know much more than we do

Choosing a pump appropriately means taking into account comprehensive technical and economic factors such as the investment and operating costs of the pump unit and the pumping station, so as to ensure compliance with the principles of economy, safety, and suitability. Specifically, there are the following aspects: The pump must meet the requirements regarding flow rate and head; in other words, the operating point of the pump (the intersection of the device’s performance curve and the pump’s performance curve) should remain within the high-efficiency range as much as possible. This not only helps to save energy but also reduces the risk of damaging the pump’s components. The pump selected must be small in size, light in weight, and inexpensive, while also having good performance characteristics and high efficiency. It has excellent cavitation resistance, which not only reduces the construction requirements for the pump’s structure but also prevents cavitation, ensuring stable operation and a long service life. Selection steps: Step 1: List the basic data: 1. Properties of the medium: name of the medium, specific gravity, viscosity, corrosivity, toxicity, etc. 2. The diameter and concentration of solid particles contained in the medium. 3. Medium temperature: (°C) 4. Required flow rate: For general industrial pumps, the leakage in the piping system can be ignored in the process flow, but the impact of process changes on the flow rate must be taken into account. 5. Pressure: pressure in the water intake tank, pressure in the water discharge tank, and pressure drop (head loss) in the piping system. 6. Pipeline system data (pipe diameter, length, types and quantities of pipeline accessories, geometric parameters from the suction tank to the pressure tank, etc.). If necessary, the device characteristic curve should also be prepared. When designing and arranging pipes, the following points should be taken into account: A. Select the pipe diameter appropriately. A larger pipe diameter results in a lower flow velocity at the same flow rate, thereby reducing friction losses; however, it increases costs. A smaller pipe diameter leads to a sharp increase in friction losses, which in turn requires a pump with higher head pressure, greater power consumption, and higher costs as well as operating expenses. Therefore, a comprehensive consideration from both technical and economic perspectives is necessary. B. The discharge pipe and its fittings should be designed to withstand the maximum pressure they can handle. C. The piping layout should be arranged as straight as possible; accessories within the pipes should be minimized, and the length of the pipes should also be reduced as much as feasible. When bends are necessary, the radius of curvature of those bends should be 3 to 5 times the diameter of the pipes, with the angle being as large as possible, exceeding 90°. D. A valve (such as a ball valve or globe valve) and a check valve must be installed on the discharge side of the pump. Valves are used to adjust the operating point of the pump, while check valves prevent the pump from rotating in reverse when fluid flows backward, thus protecting the pump from water hammer effects. (When the liquid flows back, a huge reverse pressure is generated, which can damage the pump.) Determining flow rate and head: II. Determination of flow rate: a. If the minimum, normal, and maximum flow rates are specified in the production process, the maximum flow rate should be taken into consideration. b. If only the normal flow rate is specified in the production process, a certain margin should be considered. For high-flow, low-head pumps with ns>100, the flow margin is set at 5%, for ns

Thank you all; through your explanations, I have learned a lot. Thank you.

I recommend a book titled \"Principles of Chemical Engineering\", edited by Tan Tianen and published by the Chemical Industry Press; it is written in quite detail