3 Powerful priming arrangements Of all time | Onboard Centrifugal pump

Is Priming Necessary in Centrifugal pumps?

Removing air out of the suction line and letting water in. That's Priming.

When you hear "SUCK" You might Recall our green educator pump on the Bottom platform.

Well, we use a similar method to SUCK out the air from the centrifugal pump casing.

"All Centrifugal pumps mounted above the level of the liquid needs to be primed"

Now, one of your one juniors comes from behind and asks you this:

Sir, Why are we priming Bilge pump? it's a Positive Displacement pump; right?

We could answer like this:

Son, Listen Up; and Inject your refined knowledge on Centrifugal pumps. Awesome.!

1. Central priming system

There is a vacuum pump
  • Which maintains vacuum in the vacuum chamber (Check the diagram below)
  • This vacuum chamber is connected to different pumps by the solenoid valve.
  • Whichever pump is not taking suction - when started; the solenoid valve opens and sucks the air out.
And once the pressure is developed, the Solenoid valve closes.

Each pump has an individual solenoid valve.

Centrifugal Pump Priming and central priming arrangement
A self-explanatory diagram showing a vacuum pump and vacuum tank.

2. Self priming centrifugal pump

Priming With the help of a liquid ring pump.

Check the diagram below for the Liquid ring pump which is driven by the motor-
through a friction clutch arrangement.

This liquid ring pump attached here is a positive displacement pump that sucks vapor from our main centrifugal pump along with water from its own water tank.

Centrifugal Pump Priming and self priming arrangement
The basic arrangement of a self-priming arrangement that's seen onboard

In short,

As long as there is water in the discharge side of the pump, 
the air extraction pump isn't rotating.

Self priming arrangement of the centrifugal pump by Sriram sir

As he beautifully explains the air extraction pump and priming arrangements.

The Float check valve and filter should be always clean from marine growth, fishes, and sea monsters.

As seawater has plenty of it.

Here is another compact diagram.

This one flows easily out of memory. Consider Pinteresting this.!

Centrifugal Pump Priming and self priming arrangement easy
An easier self priming arrangement for Centrifugal pumps

It's always a good idea to check the water level in the tank while taking rounds.

So that
Even if you have to start EM'CY fire pump from ECR, You have a peace of mind.

How Exactly Does a liquid ring pump work? What's the secret?

Working of liquid ring pump which removes air from our main centrifugal pump

3. Priming centrifugal by air Ejector

Everything works similar here,

If the pump is started, and if there is no pressure in the pressure transmitter, 

  • The 2 Solenoid valve opens (Check the diagram below)
  • 7 bar air keeps flowing through the air eductor
  • Eductor creates vacuum and takes out air from our pump casing.
And water floods into the pump casing.
then pressure transmitter senses this pressure and the solenoid valve closes.

Centrifugal Pump Priming using air ejector

So, why do we prime bilge our pump, which is a positive displacement pump?

- It should not run dry. 
the rubber stator may get heated up - even if it's dry for a minute. 

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If you are having any snippets of information on priming centrifugal pump,

feel free to add them in the comment section.

Have a nice day and Thank you. Ciao for Now.!

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