What Are The Considerations For Selecting, Using, And Maintaining Multi-stage Pumps

Dec 21, 2024

Selection of multi-stage pumps

When using a stainless steel multi-stage pump, the first step is to determine the purpose and performance parameters of the multi-stage pump and select the pump type. Principles and basis for selecting multi-stage pumps:

1. Make the selected multi-stage pump type and performance meet the requirements of process parameters such as device flow rate, head, pressure, temperature, cavitation allowance, suction stroke, etc.

2. Multi stage pumps must meet the requirements of medium characteristics.

(1) For pumps transporting flammable, explosive, toxic or valuable media, reliable shaft seals or leak free pumps are required, such as magnetic pumps (without shaft seals, using isolated magnetic indirect drive);

(2) For multi-stage pumps transporting corrosive media, it is required that the convection components use corrosion-resistant materials, such as fluoroplastic corrosion-resistant pumps;

(3) For multi-stage pumps transporting media containing solid particles, it is required that the convection components be made of wear-resistant materials, and if necessary, the shaft seal should be flushed with clean liquid.

3. Mechanical requirements for multi-stage pumps include high reliability, low noise, and minimal vibration.

4. Accurately calculate the input cost of multi-stage pump procurement, including procurement cost and installation and maintenance cost.

Maintenance and upkeep of multi-stage pumps

(1) Check for any looseness in the multi-stage pump pipeline and joints. Rotate the multi-stage 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 multi-stage 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) Jog the motor and check if the motor direction is correct.

(6) If the multi-stage pump is not used for a long time, it is necessary to disassemble the pump completely, dry off the water, and apply grease to the rotating parts and joints before installation.

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

(8) During the operation of multi-stage pumps, the bearing temperature should not exceed 35C of the ambient temperature, and the maximum temperature should not exceed 80C.

(9) If any abnormal sound is found in the multi-stage pump, it should be stopped immediately to check the cause.

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

(11) Within the first month of operation, the multi-stage pump needs to change the lubricating oil after 100 hours, and then every 500 hours thereafter.

(12) Multi stage pumps often adjust the packing gland to ensure normal dripping inside the packing chamber (preferably dripping out).

(13) Regularly inspect the wear of the multi-stage pump shaft sleeve, and replace it promptly if there is significant wear.

(14) When using a multi-stage pump in the cold winter season, after parking, it is necessary to unscrew the drain plug at the bottom of the pump body to drain the medium completely. Prevent frost cracking.

(15) Start the motor, when the multi-stage pump is running normally, open the outlet pressure gauge and the inlet vacuum pump to see if they display the appropriate pressure, gradually open the gate valve, and check the motor load at the same time.
5. Installation and Operation: Proper installation and operation are critical to the performance and longevity of multi-stage pumps. The pump should be installed following the manufacturer's instructions, and care should be taken during start-up and operation to prevent damage to the pump.
In conclusion, selecting, using, and maintaining multi-stage pumps requires careful consideration and attention to detail. By carefully evaluating the operating conditions, energy efficiency, maintenance requirements, reliability and proper installation and operation of these pumps, they can provide years of safe and effective service.