For slurry pump, according to the particularity of its medium, we call it slurry pump which is suitable for conveying liquid (medium) containing suspended solids. Mud pump, impurity pump, dredge pump, desilting pump, etc. are all within the application scope of slurry pump. At present, they are one of the indispensable equipment in the process of beneficiation, coal preparation, desulfurization, filter press feeding, etc.
The slurry pump is widely used, and the medium it transports is more and more complex. While we require to reduce the abrasion of slurry pump, we also have strict requirements on the sealing of slurry pump. If the sealing performance is not good, it will leak a lot of medium, resulting in unnecessary loss
Therefore, sealing is a top priority. Here are three sealing methods for slurry pump: gland packing seal, expeller seal and mechanical seal.
First of all,Gland packing seal is the most popular type of seal for slurry pump. Clean water at a certain pressure being injected into the packing through the lantern restrictor, preventing leakage from casing.
The pressure of shaft seal water must exceed the outlet pressure of slurry pump by 1.5kg. When transporting corrosive materials, it may cause corrosion to the packing, so the disadvantage of this sealing form is that it can not transport toxic and corrosive liquid. The packing shaft seal has the advantages of simple structure, convenient maintenance and low price, which is widely used in concentrator and coal washery.
Packing seal is the most common seal, which is filled with shaft seal water.Continuously inject a certain amount of pressure water into the packing to prevent the slurry body of the pump from leaking.
For the multi-stage series pump which is not suitable to use the expeller shaft seal, it is very suitable to use the packing shaft seal.
The packing shaft seal of slurry pump has simple structure, convenient maintenance and low price.
The expeller generate a reverse centrifugal force to prevent the leakage. Suitable for most slurry pumping applications providing a major advantage where no gland water is required.
The use of the expeller seal requires that the pouring pressure of the slurry pump shall not exceed 15% of the outlet pressure of the slurry pump. The single-stage pump or the first stage pump of the multi-stage series pump can use the expeller shaft seal. The expeller shaft seal has the advantages of no need of shaft seal water, no slurry dilution, good sealing effect, etc. Therefore, when dilution is not allowed in the slurry, or when there is no flushing water at the user’s operation site, such sealing can be considered.
Mechanical seal is used for applications where no extra substance is allowed to mix with the fluid being pumped, such as chemical or food industry.
The mechanical seal is that the moving ring and the static ring are closely contacted by the spring along the axial direction to achieve the sealing purpose. The mechanical seal is reliable and almost leak free, but pay attention to protect the friction surface to avoid wear during installation. Mechanical seal is generally divided into single face mechanical seal and double face mechanical seal.
Mechanical seal is generally used when the sealing requirements are relatively high, especially in some chemical and food fields, it is not only required to seal, but also the most important thing is that no additional ingredients are allowed to enter the pump body. The disadvantages of mechanical seal of slurry pump are high cost, difficult maintenance, etc.
The service conditions of each mechanical seal are different. The appropriate mechanical seal shall be selected according to the characteristics of slurry pump medium and the use of field flushing water. Mechanical seal is mainly used to transport flammable, explosive, high temperature, high pressure, strong corrosive liquid to make up for the lack of gland packing seal.
The end user selects a reliable slurry pump to run on site. Not only the flow passage parts should be made of appropriate materials, but also the shaft seal should be made of appropriate sealing methods. According to the characteristics of the transportation medium and the working conditions of the site, a suitable slurry pump seal is selected, which can not only ensure the reliable and long-term operation of the pump, but also reduce the investment loss in economic aspects. Each sealing method has its advantages and disadvantages, according to the use of experience, comprehensive consideration of various factors can play its maximum use value.
If you need to select the correct slurry pump sealing type, please feel free to contact Gempump China. Our Slurry pump engineers will choose the suitable sealing form of slurry pump for you, free of charge.