What are the performance parameters of the marine pump?

In order to indicate the performance of the pump, the following performance parameters are usually given on the pump nameplate and instructions for easy selection and comparison.

1. Displacement, also known as flow. It refers to the amount of liquid that the pump can deliver in a unit of time.

The volume flow is called volume flow, which is usually expressed by Q, and the unit is m3/s, or m3/h.

The mass flow is called mass flow, which is usually expressed by G, and the unit is kg/s, or t/h.

The displacement marked on the nameplate is the displacement of the pump under rated conditions, called theoretical displacement. In fact, the amount of fluid discharged by the pump is always less than the theoretical displacement.

2. Indenter, also known as the head. Refers to the energy delivered by the pump to a unit of weight liquid, usually expressed in H, in meters. If the lift is used to increase the liquid potential and assume that there is no loss of pipe resistance, the lift is the height at which the pump can raise the liquid.

3. Power refers to the amount of work done in a unit of time, in watts. The power of the pump is divided into output power and input power.

The output power (effective power) of the pump is the energy actually delivered to the liquid by the pump per unit time.

The input power of the pump, also called the shaft power, refers to the power transmitted by the prime mover to the pump, denoted by P. The power marked on the pump nameplate refers to the input power of the pump. Since the pump has various energy losses in actual operation, the effective power of the pump is always less than the shaft power.

4. Efficiency is the ratio of the effective power of the pump to the shaft power, expressed as a percentage.

5. The speed refers to the rated number of revolutions per minute of the pump shaft. Commonly used n means that the unit is rpm. The speed of the reciprocating pump is often expressed in terms of the number of double strokes per minute of the piston, in units of times per minute. Most pumps are driven directly by the prime mover at the same speed. However, the electric reciprocating pump generally needs to be decelerated, so the speed of the pump shaft is lower than that of the prime mover.