"What happens to the sealed water system in a slurry pump when the feed tank runs out of load (slurry)"

This question involves the gland assembly (also known as the stuffing box) in the mud pump wet seal system. The purpose of this "packing gland seal" is twofold: First, it stops excessive leakage in the pump by closing the gap between the shaft and stationary housing. Second, it lubricates the rotating shaft and helps prevent it from overheating. The seal consists of a rope into which liquid penetrates, dissipating heat and reducing friction.

There are two types of packing gland seals, the most basic one uses a pumped fluid as lubricant and coolant, while a flush gland seal uses an auxiliary pump and a clean water source. The former leaks a little, while the latter dilutes a little.

Therefore, if the seal is allowed to dry out while the pump is still running, friction may develop between the rotating shaft and the seal, and may even cause frictional wear of the stationary casing of the volute wall. This friction causes parts to wear and generate heat, which means wasted energy and the need to disassemble the pump, replace worn parts and repackage burned seals.

Even if the pump is shut down while drying, you may experience a brief increase in leakage as the seals rewet when the slurry is resupplied.

Of course, in the case of using a flush sealing gland, the gland should not dry out when the slurry supply is stopped. However, due to insufficient pressure within the pump casing, clean water consumption and its associated costs will increase.

How to prevent dry sealing?

Run the pump only when sufficient fluid is supplied. It is best to allow the feed to top off before starting the pump to reduce the number of starts, thereby reducing energy costs and reducing pump wear. Additionally, shutting down the pump before it dries out has the following advantages:

1.It is unlikely that the pump will need to be restarted the next time it is started.

2. The seal will stay wet longer.

3.Reduces the risk of cavitation damage (cavitation damage occurs when the feed pressure is too low)

Notes; If your slurry has been sitting for a while and may solidify or harden, flush the system with water before shutting it down.

Alternatives to wet seal systems:

Secondary impeller seals and mechanical seals are high-performance alternatives to traditional gland packing seals. For environments or liquids that require leak-free pumping, the ultimate shaft sealing system is a precision mechanical seal. These products feature precise tolerances that eliminate the need for gland seal packing, significantly reducing maintenance costs and are ideal where leakage is unacceptable.