Function of shaft seal device: Because there needs to be a certain gap between the rotor and the pump casing, a sealing device is installed at the part where the pump shaft extends out of the pump casing. The seal at the suction end of the water pump is used to prevent air from leaking in, destroying the vacuum and affecting water absorption, and the seal at the outlet end can prevent high-pressure water from leaking out.
Packing seal device (packing)
I. Structure
Mainly composed of: shaft sleeve, packing culvert, packing, water seal, etc.
1. Shaft sleeve: It is used to protect the shaft, prevent liquid from corroding the shaft and prevent the shaft from directly rubbing against the packing.
2. Packing culvert and packing: (packing box and packing) play the role of isolating the outside from the inside of the pump casing to reduce leakage.
3. Water seal: The water seal ring is added to the seasoning culvert and aligned with the external water seal pipe. When working, the small holes and grooves around the water seal ring form a water ring, thereby preventing air from leaking into the pump. It can also lubricate and cool the packing and sleeve, and prevent a lot of wear on the packing and sleeve.
2. Leakage treatment
Working process: To reduce the amount of leakage, the packing should be installed in the correct way first.
1) First, the packing hopper should be thoroughly cleaned, and the outer surfaces of the sleeve and the packing hopper should be checked to see if they are intact and if there is any obvious wear.
2) The specifications of the packing should be selected according to the regulations, the performance should be adapted to the liquid being transported, and the size should meet the requirements. Too thin will leak.
3) When cutting the packing, the blade should be sharp, the interface should be cut into an angle of 30o to 45o, and the cut surface should be flat. After the cut packing is installed in the packing hopper, it must be a full circle, not short or too long.
4) After the packing is installed in the packing hopper, the adjacent two circles of interfaces should be staggered by at least 90o. If it is equipped with a water cooling structure, pay attention to staggering the packing with the cooling water inlet of the packing hopper, and align the annular chamber of the water seal ring exactly with the water inlet.
5) After installing the last ring of packing, install the packing gland and tighten it evenly until the packing is confirmed to be in place. Loosen the packing gland and tighten it again to the appropriate tightening force. (Generally, it is best not to tighten the packing or tighten it slightly after installing it. After the pump is filled with water, tighten the packing, but there should be a slight amount of leakage in the packing. After the pump is started, tighten the packing according to the temperature and leakage of the packing. That is, the leakage cannot be too large and the temperature cannot be too high.)
6) After tightening the packing, check the gap between the packing gland and the shaft. The gaps around should be the same; check whether the pressure around the gland is the same. Prevent friction between the gland and the shaft.
III. Inspection after filling the packing
Check whether the tightening force of the packing gland fastening nut is appropriate. If the tightening force is too large, the leakage will be reduced, but the friction between the packing and the sleeve surface will increase. In severe cases, it will heat up and smoke until the packing and sleeve are burned; if the tightening force is too small, the leakage will be large. Therefore, the tightening force must be appropriate, and the liquid should be allowed to gradually reduce the pressure through the gap between the packing and the sleeve and form a layer of water film to increase lubrication, reduce friction and cool the sleeve. After the pump is started, it is best to keep a small amount of liquid flowing out of the packing jar. The gland tightening force can be adjusted after the pump is started.