Table of Contents
- 1 What will happen if discharge valve of submersible pump is closed?
- 2 What are the dangers of closing the water valves when the pump is on for what type s of pump is this safe?
- 3 Should the discharge valve be open or closed when starting the pump?
- 4 What happens when you restrict the discharge of a centrifugal pump?
What will happen if discharge valve of submersible pump is closed?
If the discharge valve is closed and there is no other flow path available to the pump, the impeller will churn the same volume of water as it rotates in the pump casing. The vapor can interrupt the cooling flow to the pump’s packing and bearings, causing excessive wear and heat.
What are the dangers of closing the water valves when the pump is on for what type s of pump is this safe?
At shut-off, the input energy is converted into heat, which can build up, resulting in a dangerous temperature rise of the liquid being handled and of the pump elements that are in contact with it. When almost any centrifugal pump is started against a closed discharge valve, the pump head will be higher than normal.
How do you adjust the flow rate of a reciprocating pump?
The easiest way to change the flow of a reciprocating pump is to change the rate at which the plungers/pistons move liquid through pump valves into the system.
Is submersible pump a positive displacement pump?
Submerble positive displacement pumps eliminate the problem of the suction height. Where dry pump installations lose their suction power at heights above 7meters, a submersible/dewatering pump can go as deep as necessary. The pump uses its ability to force the fluid up rather than use energy for the suction.
Should the discharge valve be open or closed when starting the pump?
If you start the pump with discharge valve open, the discharge head will act on the pump ie, more resistance, so the motor has to give more starting torque to the pump which means more current is drawn by the motor. >If you start the pump discharge valve closed, it means no discharge head minimum resistance to the pump and minimum current drawn.
What happens when you restrict the discharge of a centrifugal pump?
Throttling/restricting the discharge of a centrifugal pump lowers the motor amperage because there is less flow therefore less HP demand on the motor. Increasing the opening of the discharge valve causes even higher amperage on the motor.
What happens when the by-pass valve is closed on a pump?
With the by-pass valve is closed the pump and motor will usually make slightly more noise and draw more current. This set up is also used on many other type pumps. Full load current will only be drawn when the by-pass valve is completely closed. Do not reduce the diameter of the impeller.
Why is my centrifugal pump motor not working?
If a centrifugal pump motor cannot run with the discharge throttled without tripping and the overload protection is set correctly, the odds are very high that the motor is under-sized for the application or there is a mechanical overload being caused by a pump component or motor component failure.