It is common type, injected a certain pressure sealing water continuously into the packing, to prevent leakage of slurry pump: suitable for inline pumps which can not use expeller seal.Gland packing seal has advantages of simple structure, easy maintenance, cheap price.
Expeller seal/Centrifugal seal
Through a reverse centrifugal impeller forces to prevent slurry leakage. At the pump inlet pressure is not greater than the slurry pump outlet pressure value of 10% when a single-stage or multi-stage first pump can be used expeller shaft seal. Expeller seal has not need shaft pressure water or does not dilute slurry good. Therefore, in the case of diluted slurry is not allowed, it can be considered expeller seal.
The sealing is generally relatively high demand situations. In particular, some chemical, food industry, not only requires sealing, but most are not allowed to add extra ingredients into the pump. Disadvantages are high cost, maintenance difficulties.