Centrifugal Pump

 Centrifugal Pump 

What is a Pump ?

Pump is a hydraulic machine which convert mechanical energy to hydraulic energy. (Hydraulic energy is pressure energy).

What is centrifugal pump ?

A pump which lifts a liquid from a lower level to a higher level by the action of a centrifugal force is called as a centrifugal pump.

 

Centrifugal Pump Startup Check Points :

 

Safety Check Point :

• Pump connected all line are no maintenance and no open line.

• Flange guards are available on every flanges.

• Earthing of pump and line should be check.

• As per work condition Use all PPE’s.

• Availability of –

• SOP

• MSDS of chemical

• Safety shower should be in working condition.

• passage/path way is clear.

• Antidote of chemical.

• Spill kit/cleaning agent should be  available.

• Diphortine kit/first aid kit should be available.

 

Start Seal / Gland Colling Valve :

• Open seal cooling inlet valve.

• Open seal cooling outlet valve.

• Seal cooling pressure outlet pressure is 1.2 to 1.5 times of maximum pump discharge pressure. This pressure setup will be prevent liquid came out from casing.

• Example : If pump discharge pressure is 5 kg/cm2 than seal cooling pressure 6 to 7.5 kg/cm2.

Seal cooling flow should be adjusted generally 100 to 600 liter per hour it can be adjusted seal liquid outlet temperature.

 

Start The Pump:

• Start the motor and observe the pump’s behavior.

• Check for unusual noises or vibrations.

• Ensure that the pump builds pressure, and the motor amps are within acceptable limits.

 

Observe Pump Performance :

• Check the discharge pressure and flow rate to ensure they are within the expected operating range.

• Check the temperature of the pump casing, bearings, and motor to ensure they are not overheating.

• Inspect for any leaks at the seals, gaskets, or flanges.

 

Final Adjustments :

• Adjust the flow rate by controlling the discharge valve to meet system requirements.

• Verify that all parameters (flow, pressure, temperature, vibration, and noise levels, ampere, Voltage) are within safe operating limits.

• Running the pump without proper priming will cause cavitation and damage the impeller.

• Starting with the discharge valve fully open can lead to mechanical shock and water hammer.

• Look for signs like loud noises, vibrations, and fluctuating pressure that indicate cavitation.

 

How  Centrifugal Pump Works ?

• When pump started liquid arriving in casing.

• Impeller rotation create liquid vortex in upward direction of impeller.

• This vortex create suction at impeller eye.

• Impeller eye is near to pump suction part and create continuous suction flow.

 

 

Centrifugal Pumps Parts :

01. Casing

02. Impeller

03. Shaft

04. Stuffing Box

05. Mechanical Seal

06. Bearings

07. Spider

08. Strainer

 

01. Casing : 

It is airtight chamber in the which the impeller rotate.

It is provided Inlet (suction0 and outlet (discharge) for the liquid pumped.

Function of casing is kinetic energy convert into pressure energy.

 

Classification Of Casing :

01. Volute Casing :

Simple volute casing :

In this type of casing space between casing and impeller is lower it produce eddy resistance due to lower initial gap so it requires more energy motor or higher RPM to develop pressure.

 

Vortex Casing :

Vortex casing is updated version of volute casing in which circular chamber is provided which eliminates eddy resistance.

 

 

02. Diffuser Ring Casing :

This type casing used in turbine  type centrifugal pump there is guide vans around impeller which are in a ring.

This type of casing is maximum convert fluid kinetic energy into discharge pressure minimum design losses.

 

 

02. Classification Of Impeller :

 

01. Open Impeller :

In this type impeller blade are directly connected to impeller eye.

This type of impeller used in to pump higher viscos liquid.  like paper pulp & sewage.

 

02. Semi-open Impeller :

In this impeller eye and blade is forger on base plate.

This is use to pump liquid with solid particles.

 

03. Close Impeller :

Most efficient impeller wide range of application with normal clean viscous liquid fluid is also known as shrouded type of impeller

 

04.  Non Clogging  Impeller :

A non-clogging impeller is specifically designed to handle fluids that contain large solids, fibrous materials, or debris, such as those found in sewage, wastewater, or industrial applications.

 

05. Axial Flow Impeller :

An axial flow impeller is a type of impeller commonly used in pumps and mixers, designed to move fluid in a direction parallel to the pump shaft (along the axis).

Axial flow impellers are efficient at moving large volumes of fluid with relatively low pressure, making them ideal for applications where high flow rates are needed.

 

06. Radial impeller :

A radial impeller is a type of impeller used primarily in centrifugal pumps to move fluids by creating high pressure and low flow rates.

 

07. Mix Flow Impeller :

A mixed flow impeller combines features of both axial and radial flow impellers, offering a balance between high flow rate and moderate pressure.

 

 

03. Shaft :

Shaft is used to connect driver to pump impeller to transmit power magnetically coupled pump also available to avoid use to shaft.

 

04. Stuffing Box :

It is used to seal casing with use of packing material and lantern ring.

 

05. Mechanical Seal :

Mechanical seal is used to prevent leakage of under pressure liquid into casing.

 

06. Bearing :

It used for smooth operation of pumping generally two bearing available

01. Drive Side

02. Non Drive Side

 

07. Spider : 

It is used for coupling and drive.

It is placed in between teeth of pump and motor.

 

08. Strainer :

A strainer is a mechanical device used to filter out solid particles or debris from liquids, gases, or other fluids.

Strainers are designed to allow fluids to pass through while trapping unwanted solids, helping to protect equipment such as pumps pipelines from damage or clogging.

They are commonly used in industries like water treatment, chemical processing, oil and gas, and food and beverage.

 

 

Centrifugal Pump Advantage :

• It is simple in construction.

•  Due to its simplicity of construction, it can be made in a wide range of materials.

•  Low initial cost and simplicity of design.

• It operates at high speed and hence, can be coupled directly to an electric motor. In general, higher the speed, smaller the pump and motor required for a given duty.

•  It gives a steady delivery / discharge.

• Lower maintenance (compared to other pumps) costs.

• It does not get damaged even if the delivery line becomes blocked, or the delivery valve is closed, provided the pump does not run in this condition for a prolonged period.

•  It can handle readily liquids containing high proportions of suspended solids.

• For equal capacity, the centrifugal pump is much smaller than any other type of pump. Therefore, it can be made into a sealed unit with the driving motor and immersed in the suction tank.

 

Centrifugal Pump Disadvantage :

• It is not usually self-priming.

• It operates at low efficiencies (50 – 65%).

• It cannot handle very viscous liquids efficiently.

• It does not develop a high pressure. Multistage pumps will develop greater pressure heads but they are much more expensive and cannot be made into corrosion resistant materials because of their greater complex construction.

• If a non-return valve is not provided in the delivery or suction line, the liquid will run back into the suction tank (reservoir) as soon as the pump stops.

 

Read More : Type Of Pump