What is the major advantage of a rotary pump compared to other types of pump?

Rotary pumps can deliver high-viscosity fluids with a smaller reduction in efficiency than other pump types. Rotary pumps can handle fluids with viscosities varying from LPG (not recommended for continuous service) to very viscous greases.

Can a centrifugal pump running with discharge valve closed?

If the discharge valve is closed and there is no other flow path available to the pump, the impeller will churn the same volume of water as it rotates in the pump casing. If the pump is run in this condition for a significant amount of time, it will become damaged.

When the speed of a centrifugal pump is constant?

Centrifugal Pump MCQ Question 11 Detailed Solution If the speed is kept constant, the variation of manometric head, power and efficiency with respect to discharge gives the operating characteristic curves of a pump. The abscissa represents the discharge of the pump.

Where is rotary pump used?

Rotary pumps are commonly used for pumping high viscosity liquids such as oil including in handling lube oil and fuel oil in engine rooms. They are typically classified based on the type of rotating element they utilise.

What are the advantages and disadvantages of centrifugal pump?

Centrifugal Pump – Advantage & Disadvantage

• Small in size, space saving & less capital costs.
• Easy for maintenance.
• No danger creates if discharge v/v is closed while starting.
• Deal with large volume.
• Able to work medium to low head.
• Able to work medium to low viscous fluid.

What is slip in centrifugal pump?

Slip is the internal back flow of fluid in a pump returning from the discharge side to the suction side. In a centrifugal pump, slip is the loss of efficiency from a theoretical ideal arising from design constraints and turbulence at the impeller vanes.

What is the difference between a centrifugal and rotary positive displacement pump?

Being lower speed pumps than the centrifugal design, rotary positive displacement pumps with larger pumping chambers such as progressive cavity, lobe and peristaltic pumps are typically low shear pumps that provide a smooth flow.

What happens when the RPM of a centrifugal pump is increased?

The pump discharge/flow and the pressure/head increases with increase in rpm. keeping the impeller diameter constant. Consequently, power requirement also increases . When the rpm of a centrifugal pump goes faster, the intake end will increase to suck all water in and the output will increase too, more water will come out.

What is the difference between reciprocating and rotary pumps?

Most rotary pumps are self-priming and along with that have the ability to handle fluids consisting of liquids with entrained gas or vapour. Compared with the high pulsations and definitive batched flow of the reciprocating types, the rotary has a more continuous flow with lower pulsation levels.

What is the difference between dynamic and displacement pumps?

Dynamic pumps can be sub-classified as centrifugal and special effect pumps. Displacement pumps can be sub-classified as rotary or reciprocating pumps. In principle, any liquid can be handled by any of the pump designs.