Pumps – what they are, classifications, components


Sweet lookin’ fire pump

Excellent.  The end of 2013, the first training I have decided to put up is going to be about pumps.  For this module, we are going to take at quick look at pumps.  The actual engineering definition, the different classifications and why they may be chosen that way, and maybe some other garbage about them.  Eventually, the next pump training section will be up and we will go from there.  Cool?

What Is a Pump?

A pump is basically a device that uses an external power source to apply force to a fluid in order to move the fluid.

Simple right?  And here there were guys scaring us with big fire pumps, maybe seawater pumps in the military.

A shaft, a big long pole, is sitting there in mid-air.  I hadn’t realized how porno engineering sounds until starting to write here.  But wait, on one end of the shaft is a motor, keyed to it, so that they both rotate.  If the motor is on and rotating – so is that shaft.  For a pump, the other empty end of that shaft isn’t so empty my friends.  It has an impeller attached, submerged in the fluid you want to move.  That’s all a pump is.


Basic pump diagram.

Everywhere and anywhere.

Check this engineering concept:

A pump develops no energy of its own.

It converts the energy from the external source into mechanical kinetic energy, which shows up how?  Kinetic energy —> think velocity/moving —> the movement of the fluid.  The kinetic energy created is used to get the fluid to do work son.  And that’s what building engineering is all about – heat and energy transfer, kinetic and potential energies, coffee, & fluid motion.  In that order.

Types of Pumps


Condenser water pumps

Here is a brief list of types of pumps you may encounter in your building engineer role.  It is not meant to be all inclusive because hey, I’m just a regular dude with no college degree.  If you know of any that should be included, give me a shout and let me know.

I don’t know much about most of these but I know some stuff about centrifugal which will be the main ones we’ll encounter. Just like valves, pump types and classifications all have their advantages and disadvantages.  This is why building designers select certain pumps for certain system applications.  This is why you as competent, moving upward building engineers should speak up if you happen to notice on a drawing that the pump they are planning to install should be a reciprocating pump rather than a centrifugal. Insider info:

A centrifugal pump is considered to be a non-positive displacement pump because the volume of liquid discharged from the pump changes whenever the pressure head changes.

Where These Pumps Are

Like I said we will mainly see centrifugal pumps, I know the military uses all types due to the extremely wide variety of system applications needed.  But buildings don’t change.  They are designed for the climate, environment, and people of their area.  Once erected, big baby buildings just need to be fine tuned. Most buildings use centrifugal pumps for their chilled water plant pumps, both chilled water and condenser water, as well as for the fire pump, hot water, and domestic water. Centrifugal pumps can vary their output which makes them awesome for building uses.  For instance, some reciprocating pumps, always churn out the same amount with each turn of the pump. One case where you might run into a variable stroke pump or similar out in the building world would be for like a fuel oil transfer system – a fluid that needs to be delivered at a certain rate maybe? Anyways, I hope to eventually have this pump training series continue and the list of pump classifications just above will link you to my pages about those specifically.

Basic Components of a Pump

basic components of pumps

Basic pump components

As you can see from this drawing, the internal parts of a pump are very simple.  Man is pretty frickin’ brilliant no?  One day way back, some pioneer or Roman person (could have been a woman) decided they needed a way to move water somewhere else without having to carry it.  And they came up with this simple piece of machinery.

We’ve got the suction (more porn) and the discharge (more porn) – where the fluid enters and leaves the impeller of the pump.

There’s the casing which holds everything together and the eye which is the center o’ the storm matey.  Nice.

Now, the impellervolute, & diffuser is where centrifugal pumps get trick, trick, tricky.  By changing those elements OR the number of stages ON the pump itself we can change a whole lotta characteristics about a pump.


Multi-stage centrifugal pump
Cutaway shot

Like what if we had more than 1 impeller on the same shaft?  This is multi-staging and a way to classify centrifugal pumps as well. Look at this pump and its impellers.

In a volute pump, the impeller throws the fluid into a gradually larger channel in the pump casing.

In a diffuser pump, the fluid is forced through gradually widening channels in the diffuser ring and into the volute.  Almost all of the kinetic energy here can be transferred to potential energy.


That is it.  I am plumb tuckered out.

There will be more on pump basics later.  In this post we talked about what exactly a pump is, the definition.  A pump is a device that uses an external power source to apply force to a fluid in order to move the fluid.  We also covered some types and classes of pumps.  Lastly we briefly went over the internal components of a centrifugal pump.

Hope you found the first post useful!  If you would like to contribute (you could maybe write, moderate, send ideas) let me know.  Over in the sidebar there is a subscription field.  I should get notified if you sign up.  I will send a thank you email so you’ll have my address and can then mention any ideas or topics you have.  Awesome sauce.

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