Common Faults and Treatment Methods of Metered Dose Pump (Motor Drive)

1. The motor of the metered dose pump cannot start

Reasons for failure: 

(1) One-phase or two-phase power failure of the power supply; 

(2) The power supply is out of power.

Solution: 

(1) Check whether the fuse and contactor contacts are good; 

(2) Check the power supply.

2. The pressure of the metered dose pump cannot reach the performance parameters

Reasons for failure: 

(1) The suction valve and the discharge valve of the metered dose pump are damaged; 

(2) The stroke adjustment parts of the metered dose pump are damaged; 

(3) The diaphragm of the metered dose pump is damaged.

Treatment methods: 

(1) Replace with a new one-way valve; 

(2) Replace with a new stroke adjustment component; 

(3) Replace with a new diaphragm.

3. No discharge liquid or insufficient discharge volume results in a decrease in measuring accuracy

Cause of failure:

(1) The suction pipe is blocked or the suction pipe valve is not opened;

(2) The suction pipe leaks air;

(3) Air and oil leakage at the oil filling valve group or diaphragm chamber;

(4) The valve face of the suction valve or discharge valve is damaged or falls into foreign matters, which makes the valve face seal not tight;

(5) There is residual air in the diaphragm cavity;

(6) The suction pipe is too long and there are many sharp turns;

(7) Abnormal action of safety valve and compensation valve;

(8) The suction level is too low;

(9) The motor speed is insufficient or unstable.

Treatment method:

(1) Check the suction pipe and filter, open the valve; 

(2) Seal the leaking part tightly; 

(3) Find out the leaking part and seal it tightly; 

(4) Check the tightness of the valve and replace the valve and valve seat if necessary; 

(5) Refill the oil and exhaust the gas; 

(6) Enlarge the suction pipe to reduce sharp turns; 

(7) Readjustment; 

(8) Adjust the height of suction liquid level; 

(9) Stabilize the motor speed.

4. There is impact noise in the metered dose pump

Cause of issue:

(1) Each movement pair is severely worn; 

(2) The valve lift is too high.

Treatment method:

(1) Adjust or replace parts; 

(2) Adjust the lift height to avoid metered dose pump lag.

5. Overheating of metered dose pump parts

Cause of issue:

(1) The oil in the oil tank of the transmission mechanism is too much or insufficient, and there are impurities in the oil;

(2) The lubrication of each pair is not good;

(3) The ambient temperature is too high and there is no ventilation.

Treatment method:

(1) Replace with new oil to make the amount of oil suitable;

(2) Check and clean each oil hole; 

(3) Keep the ambient temperature below 60℃ with good ventilation.