Selection parameters and usage methods of metering pump


I. Selection parameters of metering pump:

1. The flow rate of the liquid being metered.

2. The main characteristics of the liquid being measured, such as chemical corrosion, viscosity and specific gravity.

3. System back pressure.

4. Appropriate suction lift.

5. Other options required, such as analog control, pulse control, flow monitoring and timer.

What are the main advantages of electromagnetically driven metering pumps?

Electromagnetically driven metering pumps have only one moving part, the armature shaft. Generally speaking, the fewer moving parts the more reliable the metering pump works. The metering pump is very suitable for low-flow and low-pressure working situations, and has a good compensation effect when the power supply voltage fluctuates.

Compared with metering pumps with fixed frequency and variable stroke length, what are the advantages of metering pumps with fixed stroke and variable frequency? Through calibration, the dosage for each stroke is known. Therefore, the total dosage can be calculated (the dosage = the dosage per stroke * frequency). The total dosage is linear with frequency (50% frequency = 50% dosage). Through external pulse or analog control, the dosage can be adjusted from minimum to maximum within one second. In addition, it is much cheaper than the motor-driven stroke length adjustment.

How to use the performance curve of the metering pump?

1. Find the performance curve corresponding to the selected metering pump.

2. Mark the current back pressure in the chart below.

3. Determine the correction factor, take the back pressure value in bar units, extend it up to the curve, and read the correction factor value vertically to the left at the intersection.

4. Divide the required dosing value by the correction factor to get the value in ml / min. Or L / h.

5. Place the calculation result in the middle of the dosage scale.

6. When this value is placed on the dosing volume scale, you can use a ruler to find out the stroke length setting and stroke frequency setting.