Hey there guys. Paul here from TheEngineeringMindset.com. In this video, we're going to be looking
at the centrifugal type pump and we're going to learn how it works. Now, the centrifugal type pump is the most common type
of pump use in industry and pretty much every commercial
and industrial building. Many of our homes, houses and apartments, even ships and aircraft, they'll all have at least one
centrifugal pump installed. It's actually pretty rare
to come across a building that doesn't have one installed. Now, larger sites, especially a commercial
and industrial buildings, they're most likely gonna
have multiple sets of pumps and this is to serve the different systems they have within the building. So typically, you know,
heating and cooling systems or anything really where
water needs to be pushed around some pipe work
throughout the building or the process. So, if you're in engineering or you're looking to get into this, you're gonna come across these very often. They're absolutely everywhere. Now in a typical setup, an induction motor is mounted at the back. A shaft is then run between the rotor of the motor over into the pump. And the impellor is then
mounted to the shaft. The induction motor rotates the shaft, which in turn rotates the impellor. Changing the speed of the motor will change the speed of
the impellor's rotation. And in this method, you can then change the
flow rate of the system. The impellor then sits
inside the pump casing where it's completely sealed in. You shouldn't be able to look inside it or any of its components. So, the centrifugal pump has two ports, an inlet and also an outlet. The inlet is always through the center, usually on a horizontal axis like this, whereas the exit is on the vertical axis. So this is known as the suction line, and this is known as the discharge line. The impellor where it's
sitting inside the pump casing, it should always be submerged in water, otherwise it will not be
able to draw sufficient flow and operate correctly. This can cause cavitation where the water inside
actually starts to boil due to the low pressure and this can cause severe
damage to the pumps impellors. The pump casing has a volute running around the circumference
of the pump casing. The volute, which is sitting on the
outside of the casing here, has an increasing diameter
all the way from the start, the inside in a most of the pump all the way around up until
the discharge or the outlet. This change in diameter
allows more water to flow and obviously that means an increase in the mass
flow rate as it comes around and overflow starts to build up. The water or fluid starts
to enter into the pump through the inlet port. As the water enters into the impellor, the force of it pushes
this out towards the edge. All the water that is
pushed against the edge is in collecting into the volute. And you can see has
this all here collecting and making its way out through the top. The impellor has these veins, these curved shapes here, and they run from the center all the way out to the outer edge. This type of impellor is known as the backwards curve type impellor, which is the most common and most efficient
design for moving water. It's important to remember that these veins do not push the
water out like a paddle. The water actually flows in between these and the veins help provide a
force, the centrifugal force, which forces that water out of the pump. To understand how this works, let's have a look at the impellor. Now when the impellor begins to spin, it creates a low pressure
suction at the inlets, this part here. This low pressure suction pulls the fluid into the center of the impellor. And we know that when you spin something, it always tries to move
away from the center away over to the outer edge. So, we have this outward force here, which shows by this line. We also know that the
item will have inertia. So, we can show that with this line here. So as this rotates, it's
gonna try and keep going out following its radial force. These forces combined give
you a resultant force. And this resultant force shows that the fluid will exit the impellor following a spiral trajectory. So the volute is therefore
shaped to match this and direct the fluid. As the water collects in
the volute, it slows down and this converts its kinetic
energy into static pressure. The water continues to
flow in behind this. And this is what pushes the water, allowing it to maintain pressure
as well as its flow rate. And this allows water to
be pushed through pipes all the way around the building. And that is why they are used
for outbuildings and systems all around the world. And this is the inside of a pump casing. You can see inside of the volute there as it's increasing and going
up towards the discharge port. I just put my hand there so you can see that's
where it would come out. And this is the view just
in through the top there, so you can see how it would channel out. This is inside the impellor. You can see the blades here. And you can just turn
it, rotate that by hand. Don't worry, it's not
connected to anything. I'm not gonna cut my hands off. I just rotate like so. And this just shows you
looking inside the pump. This is just a stock
one laying on the shelf. You can see the impellor in there and also a flow arrow indicating
the direction of flow. Now this is just the shaft
along with the rotor attach, and this would fit inside
the induction motor. And this is looking inside
the induction motor. So, the rotor would sit in here and the shaft would come out of here. That shaft will then
connect onto the impellor as shown here. And that impellor would
then sit inside here and be bolted onto it. And obviously you can see the volute here with the increasing diameter running around the circumference
of the pump casing. The pumps might not always
be direct drive for a shaft. They could also be on
a belt drive like this. This is another view of it there. This is less energy efficient
'cause you'll get some slip and some frictional losses
here from these belts. So, if you can use direct drive, they're much more efficient. Using direct drive is also
far less maintenance involved. And these pumps will, they'll keep running
for many years actually a real workhorse of the industry. But anyway, that's it for this video. Thank you very much for watching. I hope this has helped. Please don't forget to
like, subscribe and share. And if you have any questions, please leave them in the
comment section below. Also, don't forget to
check out our website, TheEngineeringMindset.com. Thanks for watching.
