Discussion on the high-flow operation of pumps
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On-site, for operating conditions where the pump is above its rated flow rate, can the pump still run? What methods can be used on-site to make the pump operate at a flow rate higher than its rated value? By how much can a general pump operate above its rated flow rate? Last time, I saw a netizen say that the outlet control valve should be set to 105% of its opening degree. How can this be achieved, and by how much can the pump operate above its rated flow rate?
1. If a pump operates at an excessive flow rate for an extended period of time, it can cause damage to the motor and the pump itself; such operation should be avoided in practice. 2. If you want to operate beyond the specified flow rate, you can use an outlet flow meter or measure the oil tank volume to determine the actual flow rate of the pump, and then compare it with the rated flow rate of the pump.
The main operating parameters of a general pump include: outlet pressure, operating current, motor temperature, and operating voltage. Among these parameters, for the same pump used to transport materials with different densities and viscosities, the outlet pressure, operating current, and motor temperature will all vary. To ensure the safe operation of the motor, it is generally sufficient to monitor the operating current and ensure that it does not exceed 90% of the rated current, thereby preventing the motor from overheating and its coils from being damaged!
When a pump operates at an excessive flow rate, the first thing to consider is whether the pump’s current exceeds its rated value; operating above the rated current means that the pump motor is under overload. Under such conditions, the heat generated by the motor exceeds the design specifications, which has a significant impact on the lifespan of the pump motor; in severe cases, it can even cause the motor to burn out. As long as it is below the rated current, it generally has no adverse effect on the pump. There are many factors that can cause excessive flow in a pump: the inlet head pressure, the diameter of the inlet pipe (valve opening), the design shape and size of the pump chamber and impeller, the diameter of the pump outlet pipe (valve opening), the kinetic energy losses resulting from the length of the outlet pipeline, as well as the power and performance of the motor. All these factors can influence the flow rate of the pump.