What are the reasons for the high leakage in the packing seal of the feed pump in a plate and frame filter press?
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The sludge dewatering equipment used in my water treatment plant’s sludge disposal system is a plate and frame filter press. The feed pump for this filter press is of the single-screw Nemo type, and the shaft end sealing is achieved using packing (ring seal). There has been a significant issue of sludge leakage at the shaft end seal; it keeps leaking, requiring frequent replacement and tightening of the seal. I would like to know what causes this leakage at the shaft seal, and what effective solutions exist
A packing seal inherently allows a certain amount of leakage, and improper installation can also cause wear in a short period of time. In this type of filtration operation, the flow rate is high and the pressure is low at the beginning; as more filter media accumulate inside the filter press over time, the pressure increases while the flow rate decreases. This is a gradual process that also has an impact on the pump seals. We generally use horizontal corrosion-resistant and wear-resistant pumps for such applications.
It’s normal for the filler to leak; as long as the leakage isn’t severe, there’s no problem. Consider trying to replace the mechanical seal
1 The filler is too cheap. 2 Add an external water seal. 3 Allow a certain number of drops per minute to leak, and there must be a collection pipe for the leaked water.
This post was last edited by CHANGBAISHI on 2020-6-12 at 14:38. Oh, I should look into diaphragm pumps. I’m not sure if the flow rate is suitable; let’s check whether the parameters of this pneumatic pump are appropriate. It requires a gas source for operation. For reference: https://detail.tmall.com/item.ht...ed55e27b&abbucket=6. Regarding seal leakage, it is important to clean the area where the packing is installed, remove any impurities between the rotor and the packing, and polish the rotor surface to ensure a smooth contact area. Due to inadequate cleaning and insufficient surface finish of the rotor, once a leak occurs, particle impurities will gradually seep out, leading to increased wear and a greater amount of leakage. For reference.
If there is flushing water available on site, it is recommended to use it; this can solve the problem either with packing or mechanical seals. These conditions are not available on-site; it is recommended to use gaskets with better self-lubricating properties, such as graphite
Also, is your filter pressing pressure higher than the sealing design pressure of the pump, or is there excessive pressure due to backflow of material during the pressing process?