The Service Life And Precautions Of Sewage Pumps

Dec 29, 2024

Sewage pumps belong to a type of centrifugal impurity and come in various forms, such as submersible and dry. Currently, the most commonly used submersible sewage pump is the submersible sewage pump, and the most common dry sewage pump is the horizontal sewage pump and the vertical sewage pump. Mainly used for transporting urban sewage, feces or liquids containing solid particles such as fibers and paper scraps, the temperature of the transported medium is usually not greater than 80 ℃. Due to the presence of fibers that are prone to entanglement or clumping in the conveyed medium. Therefore, the flow channel of this type of pump is prone to blockage. Once the pump is blocked, it will not work properly and may even burn out the motor, resulting in poor drainage. It has a serious impact on urban life and environmental protection.

How to extend the service life of sewage pumps:

1. Prohibit abnormal power supply voltage startup

Due to the long length of low-voltage power supply lines, it is common for the terminal voltage of the lines to be too low. When the phase voltage is lower than 198 volts and the line voltage is lower than 342 volts, the speed of the sewage pump motor decreases. When it does not reach 70% of the rated speed, the centrifugal switch will close, causing the starting winding to be energized for a long time and generate heat or even burn out the winding and capacitor. On the contrary, excessive voltage can cause the motor to overheat and burn out the windings. Therefore, during the operation of the sewage pump, the operator must observe the power supply voltage value at all times. If it is below 10% of the rated voltage and above 10% of the rated voltage, the motor should be stopped to identify the cause and eliminate the fault.

2. Confirm the correct rotation direction of the motor

The rotation direction of the motor should be clarified. There are many types of sewage pumps that can produce water in both forward and reverse directions, but the water output is small and the current is high in reverse. If the reverse time is long, it will damage the motor winding.

3. Installation of leakage protector

Leakage protector, also known as life protector, can be understood from the three words "life protector". Because sewage pumps work underwater, they are prone to electrical leakage, which can cause energy loss and even lead to electric shock accidents. If a leakage protector is installed, as long as the leakage value of the sewage pump exceeds the operating current value of the leakage protector (generally not exceeding 30mA), the leakage protector will cut off the power supply of the sewage pump to ensure safety and avoid leakage and energy waste.

4. Cable installation and insulation resistance requirements for submersible electric pumps

When installing a sewage pump, the cable should be overhead and the power line should not be too long. Do not put force on the cable when draining or lifting the sewage pump to avoid causing the power line to break. When the sewage pump is working, do not sink into the mud, otherwise it will cause poor heat dissipation of the motor and burn out the motor winding. During installation, the insulation resistance of the motor should not be less than 0.5 megohms.

5. Avoid frequent switching

Do not frequently turn on and off the sewage pump, as it will generate backflow when the electric pump stops running. If it is turned on immediately, it will cause the motor load to start, resulting in excessive starting current and burning out the winding. Due to the high current during startup, frequent startups can also burn out the motor winding of the sewage pump.

6. Do not let the sewage pump work under overload for a long time

To avoid long-term overload operation of the sewage pump, do not pump water with high sediment content and observe whether the current value is within the specified value on the nameplate at any time. If excessive current is found, the machine should be stopped for inspection. In addition, the dehydration operation time of the water pump should not be too long to avoid overheating and burning out the motor.

7. Pay attention to daily maintenance

Regularly check the motor. If cracks are found on the lower cover, damaged or ineffective rubber sealing rings, etc., they should be replaced or repaired in a timely manner to avoid water infiltration into the sewage pump.

Precautions for using sewage pumps

(1) Check for any looseness in the sewage pump pipeline and joints. Rotate the sewage pump by hand to see if it is flexible.

(2) Add bearing lubricating oil into the bearing body, and observe that the oil level is at the centerline of the oil gauge. The lubricating oil should be replaced or replenished in a timely manner.

(3) Unscrew the water inlet plug of the sewage pump body and inject water (or slurry).

(4) Close the gate valve, outlet pressure gauge, and inlet vacuum gauge of the water outlet pipeline.

(5) Tap the motor and try to see if the motor direction is correct.

(6) Start the motor, when the sewage pump is running normally, open the outlet pressure gauge and the inlet vacuum pump to see if they display appropriate pressure, gradually open the gate valve, and check the motor load condition at the same time.

(7) Try to control the flow rate and head of the sewage pump within the range indicated on the label as much as possible to ensure that the sewage pump operates at the highest efficiency point, in order to achieve the maximum energy-saving effect.

(8) During the operation of the sewage pump, the bearing temperature should not exceed 35 ℃ of the ambient temperature, and the maximum temperature should not exceed 80 ℃.

(9) If any abnormal noise is found in the sewage pump, it should be stopped immediately to check the cause.

(10) When the sewage pump needs to be stopped, first close the gate valve and pressure gauge, and then stop the motor.

(11) The lubricating oil of the sewage pump should be replaced after 100 hours of operation within the first month, and then every 500 hours thereafter.

(12) Regularly adjust the packing gland to ensure normal dripping inside the packing chamber (preferably in droplets).

(13) Regularly check the wear of the shaft sleeve, and replace it promptly if there is significant wear.

(14) When the sewage pump is used in the cold winter season, after parking, the drain plug at the bottom of the pump body should be unscrewed to drain the medium completely. Prevent frost cracking.

(15) If the sewage pump is not in use for a long time, it is necessary to disassemble the entire pump, dry off the water, and apply grease to the rotating parts and joints before installation.