Reciprocating pump speed issue
Thread Content
1. As shown in the figure, when the speed of the pump increases, the fluid flow rate rises as well, which leads to an increase in fluid resistance. But why does an increase in fluid resistance result in a decrease in pressure inside the pump? This can potentially cause the pump to experience vacuum conditions 2. The theoretical head of a reciprocating pump can be infinitely large; why does it possess such a property? What factors cause this characteristic of reciprocating pumps?
A reciprocating pump is a positive-displacement pump that creates negative pressure by the movement of a piston or plunger to draw in the medium and then discharge it. If the rotation speed is too high, the medium does not have enough time to fill the chamber, resulting in negative pressure and vacuum formation.
The pipelines and pumps come as a set! It’s too fast – it exceeds the maximum flow rate allowed by the pipeline! The amount doesn’t increase; it decreases, and it can no longer be drawn in! It’s easy to create negative pressure!
Thank you for the answer. One more question: since the head of a reciprocating pump is independent of its flow rate, then what determines it? Is it only related to the pipelines?
A reciprocating pump is a positive-displacement pump; as its speed increases, so does its stroke length, which in turn increases the flow rate per unit time and the fluid velocity. Naturally, this also leads to an increase in resistance. As for the pump running dry, it occurs when the liquid at the pump’s inlet cannot keep up or when the liquid at the inlet vaporizes~~
It is related to the outlet pressure, that is, the pipeline network pressure (back pressure)~~First, understand the inlet and outlet structure of the reciprocating pump~~