Water Pressure and Water Capacity of Shaft Seal of Dredging Slurry Pump
Two choices of shaft sealing methods for dredging slurry pump:
-a combination sealing with auxiliary impeller and packing
-a mechanical sealing
It is preferred to use mechanical seals with high-pressure shaft sealing water for multi stage slurry pumps (second stage or above) in serial connection. Single stage or first stage of muti stages slurry pump usually choose the sealing method of combined auxiliary impeller sealing and packing sealing.
The water pressure and water capacity of shaft seal are related to different sealing forms.
1. Shaft seal water pressure: For single stage first stage of muti stages dredging slurry pump, a combination seal of packing and auxiliary impeller is used, and the dredging slurry pump's shaft sealing water pressure is generally 0.2-0.3 MPa.
2. For multi-stage serial connection, if a combination sealing of packing and auxiliary impeller is used, the minimum pressure of shaft seal water for the second and above stages is generally:
Pn=∑Hi+0.7Hn; Hi is the head of the i-th stage pump; Hn is the head of the nth stage pump.
If mechanical seals applied, the shaft seal water pressure of each stage of the pump is generally required to be 0.1MPa higher than the pump outlet pressure.
