What should be noted when arranging pipelines for gear pumps

When designing and arranging pipelines for gear pumps, attention should be paid to the following:

A. Reasonably choose the diameter of the gear pump pipeline. The pipeline diameter is large, and at the same flow rate, the liquid flow speed is small, resulting in small resistance loss. However, the price is high, and the pipeline diameter is small, which will cause a sharp increase in resistance loss, increase the head of the selected pump, increase the matching power, and increase the cost and operating expenses. Therefore, a comprehensive consideration should be given from both technical and economic perspectives

B. The discharge pipe and its fittings should consider the maximum pressure they can withstand

C. The pipeline layout should be arranged as straight as possible, minimizing the number of accessories in the pipeline and minimizing the length of the pipeline. When turning is needed, the bending radius of the elbow should be 3-5 times the diameter of the pipeline, and the angle should be greater than 90 ℃ as much as possible

D. Valves (ball valves or globe valves, etc.) and check valves need to be installed on the discharge side of the pump. Valves are used to adjust the operating point of the pump, and check valves can prevent the pump from reversing when the liquid flows back, and prevent the pump from being hit by water hammer. (When the liquid flows back, it will generate huge reverse pressure, causing pump damage)

Secondly, the influence of gear pump flow and head

Determination of flow

A. If small, normal, and large flow rates have been provided in the production process, the larger flow rate should be considered.

B. If only normal flow rate is provided in the production process, a certain margin should be considered

For high flow low head pumps with NS100, a flow margin of 5% should be taken. For low flow high head pumps with NS50, a flow margin of 10% should be taken. For pumps with 50 ≤ ns ≤ 100, a flow margin of 5% should also be taken. For pumps with poor quality and poor operating conditions, a flow margin of 10% should be taken

C. If the basic data only provides weight flow rate, it should be converted to volumetric flow rate