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How to Select a S/S Split Case Pump

Categories:Technology Service Author: Origin:Origin Time of issue:2022-05-19
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S/S split case pump is mainly considered from flow, head, liquid properties, pipeline layout and operating conditions. Here're the solutions.


Liquid properties, including liquid medium name, 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., which involve the head of the system, the effective cavitation residual Quantity calculation and suitable pump type: chemical properties, mainly refers to the chemical corrosiveness and toxicity of the liquid medium, which is an important basis to select the split case pump material and which type of shaft seal to choose.

Flow is one of the important performance data for pump selection, which is directly related to the production capacity and conveying 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 choosing a stainless steel open pump, take the maximum flow as the basis and take into account the normal flow. When there is no maximum flow, usually 1.1 times the normal flow can be taken as the maximum flow.

The head required by the system is another important performance data for pump selection. Generally, the head should be enlarged by 5%-10% margin for selection.

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

The pipeline layout conditions of the device system refer to the liquid delivery height, the liquid delivery distance, and the liquid delivery direction, such as the lowest liquid level on the suction side and the highest liquid level on the discharge side, as well as some data such as pipeline specifications and their lengths, materials, pipe fittings specifications, quantities, etc., In order to carry out the calculation of the head of the tie-comb and the check of the NPSH.

There are many operating conditions, such as liquid operation T, saturated steam force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, ambient temperature, whether the operation is intermittent or continuous, and the position of the pump is fixed or not. removable.

For liquid pumps with a viscosity greater than 20mm2/s (or a density greater than 1000kg/m3), it is necessary to convert the characteristic curve of the water experimental pump into the performance curve of the viscosity (or under the density), especially the suction performance and input power. Do serious calculations or comparisons.

Determine the number and standby rate of S/S double suction split case pumps. Generally, only one pump is used for normal operation, because one large pump is equivalent to two small pumps working in parallel (meaning the same lift and flow), and the large pump has high efficiency. For small pumps, from the perspective of energy saving, it is better to choose one large pump instead of two small pumps, but in the following situations, two pumps can be considered in parallel: the flow rate is large, and one pump cannot reach this flow rate. For large pumps that need a 50% standby rate, two smaller pumps can be changed to work, two standby (three in total).