Flow Adjustment Methods of Metering Pumps

1. Introduction of the metering pump

The metering pump is also called the quantitative pump or the proportional pump. The metering pump belongs to the reciprocating positive displacement pump, it is used for accurate metering. Usually, the stability accuracy of the metering pump is required to not exceed ±1%. 

According to the structure type of the hydraulic end of the metering pump, the metering pump is often divided into four types: plunger metering pump, hydraulic diaphragm metering pump, mechanical diaphragm metering pump and bellows metering pump.

The flow of the metering pump can be step-less adjusted within the range of 0 to 100%. It is a special form of reciprocating positive displacement pump for transporting liquid materials (especially corrosive and dangerous liquids). The metering pump is also called the quantitative pump or the proportional pump.

2. Flow adjustment methods of metering pumps

The commonly used flow adjustment methods of the metering pump include adjusting the stroke and adjusting the number of strokes per minute. Or there are three methods including the two methods above. Among them, the method of adjusting stroke is the most widely used. It is simple and reliable, and it can maintain high measurement accuracy even at a low flow rate. There are three ways to adjust the stroke.

(1) Manual adjustment when shut down

The stroke of the metering pump can be manually adjusted when shut down.

(2) Manual adjustment during operation

The axial displacement can be changed during pump operation, which can indirectly change the crank radius to adjust the stroke length. Common methods for stroke adjustment include N-shaped crankshaft adjustment, L-shaped crankshaft adjustment and eccentric cam adjustment.

(3) Automatic adjustment during operation

Pneumatic control and electric control are the two common types. Pneumatic control automatically adjusta the stroke by changing the air source pressure signal. Electric control automatically adjusts the stroke by changing the electric signal.

NEWDOSE metering pumps are mainly electric metering pumps. Also, there are electromagnet-driven diaphragm metering pumps and motor-driven diaphragm metering pumps, with high performance and high quality.