Vertical Inline Centrifugal Pumps

21 Oct.,2022


Vertical Centrifugal Pumps

Vertical inline pumps are available in three types of design – monobloc or close coupled without coupling, rigidly coupled, or long coupled.

Monobloc or Close Coupled

In some monobloc designs, an inline pump will usually have a single shaft connecting the motor to the pump head meaning the motor bearings bear the full rotary load of the shaft during operation.This design of pump is better suited for short duties at full motor speed, and light duties. Should there be any leakage of the mechanical seal the fluid can enter the motor causing motor failure.

Replacement of the pumps internal parts can be difficult as standard off the shelf motors can not be used making sourcing more difficult, and can usually only be obtained from the original manufacturer.

Rigidly Coupled Designs

In other close coupled designs such as our SNL and ECO SNL models the pump has a separate motor & pump shaft which must be aligned and fixed in place.

The separate shafts make the pump stronger as shafts are thicker and should motor failure occur a standard motor can be easily sourced as pump design means they are more readily available.

During maintenance the motor and pump must be disassembled with the mechanical seal refitted at the same time as motor fitting.

Spacer Coupling

Spacer coupling designs such as our SNLV-H have a rigid metal bracket separating the pump head from the motor. The pump is coupled via a flexible coupling which can be removed allowing engineers to maintain the pump without disconnection of the motor.

This design has twin sets of bearings in the pump head, with another set within the motor, complete with separate shafts, meaning the pumps radial loads are shared across a large number of components.

As construction is heavy-duty it is typically used in applications demanding short maintenance periods, and low amounts of downtime as pumps can be operating 24/7 performing Engine Cooling, boiler feed, or act as fire pumps. Motor speeds will be altered accordingly being usually at 4 (1450/1800rpm), or 6 pole (700/900rpm) speeds.

Double Suction

Vertical double suction inline pumps are a variant in spacer coupling design which provide very high flows at medium heads, by the use of an impeller design which produces the flow of two impellers. This is achieved by its back to back design, where the impeller is a single piece, but appears as if two impellers have been bolted together. The below design is of split case coupled design enabling access to the impeller without full removal of the pump head from the support. 

This pump is suited for arduous applications where high flows are required in pipelines 24/7 or short bursts of duty such as in anti-heeling / ballasting operations.

Vertical Inline Vs Horizontal Pumps

- Space saving design as motor is mounted above the pump

 - If pump does not have support bracket, a crane or jib is required to take the weight of the motor

- Can not perform manometric suction lifts with footvalve installed as air can not escape meaning priming device is required.

Should space and budget allow a vertical Inline Pump with spacer coupling is the better engineered design, but a close coupled unit which has separate shafts is a good alternative durable choice. 

View our range of Vertical Pumps