Precautions for long-term shutdown of slurry pump
 

Long term shutdown of slurry pumps (such as over a week) is not a simple shutdown operation and requires standardized shutdown maintenance. Otherwise, serious problems such as impeller jamming, bearing damage, pump body corrosion, and even rupture may occur when restarted.

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 Hebei Xingou Machinery Equipment

The following are the key points to pay attention to when the slurry pump is stopped for a long time, which can be summarized as five core steps: "emptying, cleaning, rust prevention, maintenance, and regular inspection".

Ⅰ、 Operation before shutdown (the most critical step)

1. Thoroughly drain the slurry from the pump and pipeline
Why: The slurry contains solid particles. Once it is stationary for a long time, it will settle and solidify in the pump chamber, impeller, and pipeline, hardening like cement, causing the impeller to completely jam. The next time it is started, it will directly burn out the motor or break the shaft.
How to do：
After shutdown, immediately open the drain hole or flushing port under the pump casing.
Connect clean water (or specialized flushing water) to the flushing port of the pump, and flush the pump chamber and inlet and outlet pipelines in reverse or forward direction until the discharged water becomes clear, ensuring no solid particles remain.
For systems with minimum flow pipelines, they should also be flushed clean together.

2. Thoroughly clean the pump body
Why: The slurry attached to the outside of the pump body can also corrode and damage the pump components.
How to do: Use a high-pressure water gun or manually rinse off any residual slurry from all parts of the pump casing, base, flange, etc.

2、 Maintenance measures during downtime

1. Internal rust prevention and protection
Why: Pump chambers, impellers, and other overcurrent components are mostly made of metal materials, and residual water vapor can cause them to rust.
How to do:
Drain accumulated water: After flushing, be sure to open all drainage points and thoroughly drain the accumulated water in the pump.
Apply anti rust oil/grease: For longer shutdown periods (such as several months), it is best to apply new lubricating grease in the bearing box of the pump. You can spray or apply a layer of rust proof oil on metal surfaces such as impellers and pump shafts.
Place desiccant: If conditions permit, open the pump cover, place a bagged desiccant inside the pump chamber, and then close the pump cover to absorb internal moisture.

2. Maintenance of key components
Bearing: Check the lubricating oil/grease in the bearing box. If the oil quality deteriorates or water is mixed in, new oil/grease should be replaced. Ensure that the bearings are adequately lubricated to prevent rusting.
Mechanical seal/packing seal:
Mechanical seal: Keep it clean and dry. If you know the material of the seal, you can check the condition of its elastic components.
Packing seal: Loosen the packing gland to reduce long-term pressure on the pump shaft and packing, and prevent deformation.
Power source:
Motor: Take good moisture-proof protection for the motor and cover it with waterproof cloth if necessary. Disconnect the power supply.
Belt transmission: Loosen the belt to prevent it from losing elasticity due to prolonged tension.

3. Regular turning
Why: This is one of the most effective methods to prevent component adhesion and fixed point corrosion of bearings.
How to do: During the shutdown period, manually rotate the pump shaft (disc drive) with tools at least one to two turns per week or every half month. This approach can:
Prevent bearing balls from being subjected to pressure for a long time at the same position, resulting in indentation (Brinell indentation).
Lubricate the sealing surface of the mechanical seal.
Change the relative position of the impeller and pump casing to prevent small rusting from causing jamming.

Ⅲ、 Environment and Records

1. Environmental management
If possible, move the pump to a dry and ventilated room for storage.
If it is necessary to be outdoors, it must be tightly covered with waterproof cloth to prevent rainwater and dust from entering.

2. Hanging signs
Hang a warning sign in a prominent position on the pump that reads "Long term shutdown, no closing" or "Equipment to be maintained" to prevent accidental operation.

Ⅳ、 Check before reactivation

When it is necessary to reactivate the pump, do not start it directly! The following checks must be conducted:

1. Manual turning: First, rotate the pump shaft by hand to confirm that it rotates smoothly and without any jamming sensation. This is a necessary step before starting!
2. Check the connection: Check if the anchor bolts and inlet/outlet flange bolts are tightened.
3. Restore sealing: If it is a packing seal, tighten the packing gland again to the appropriate level.
4. Check lubrication: Check the oil level/grease level of the bearing box and replenish or replace it if necessary.
5. Jogging test: Connect the power supply, perform jogging (instant start immediately stop), observe whether the pump's direction is correct, and whether there are any abnormal sounds or vibrations.
6. No load operation: With the inlet valve open and the outlet valve closed (or slightly open), perform a short-term no-load operation to check if the pressure, current, vibration, and noise are normal.
7. Gradual loading: After everything is normal, slowly open the outlet valve and gradually load to the normal working state.

Following the above regulations can minimize the damage caused by long-term shutdown of the slurry pump and ensure that the equipment can be reliably put into operation at any time when needed.