The Vertical Glandless Pumps in normal hydraulic terms do not differ from any conventional centrifugal pump. The pump is designed in such a way that the liquid would normally try to pass through annular space , where the impeller drive shaft enters the back plate (stuffing box).This liquid is diverted and returns as a controlled flow to the suction tank. The need for any seal is eliminated by allowing the leakage liquid to escape through the overflow connection to the overflow chamber.
The liquid entering the suction flows around the impeller casing and leaves through the delivery under pressure. Between the annular gap of the upper rotor casing and impeller some leakage liquid escapes to the overflow chamber. The auxiliary impeller (Expeller) prevents the leakage liquid going further up and channelizes it through outlet in the overflow chamber.
These pumps are ideally suited for continuous operation for clear liquid and slurries. This pump is at its best with negative suction.

Uniqueness of Vertical Glandless Pumps

• Designed for continuous operation
• Problems associated with mechanical seal or gland is eliminated
• No bearing housing
• Self draining
• Suitable for clear liquids and slurries
• Zero safe minimum flow
• Can operate pump safely form fully open to fully closed condition
• Pump can run dry indefinitely
• Saves valuable floor space

When to Choose a Vertical Glandless Pump ?

• Where ever negative suction exist (pump is mounted above the level of the suction tank).
• Height of the suction tank is less than 5 meters
• Priming of the pump is feasible
• Ideally suited for water based inorganic chemicals like acids, alkalis, salt solutions and its slurries
• Continuous operation like scrubbing
• Recirculation or continuous fluid flow like pickling, plating etc.,
• Ideally suited for ETP Application

Limitations of Vertical Glandness Pump

• Can operate only wherever negative suction exists or can be created
• The suction lift poses a limitation in the installation ( where NPSH available is less than 3 meters)
• Can be suitable for only those liquids where priming is feasible
• Not recommended for high temperature application
• Not recommended for inflammable organic liquids
• Not recommended for acids like strong sulphuric acid or oleium where priming is not feasible