When it comes to pumping, there is a lot of science and mathematics involved to truly understand exactly what is going on.  However, there is still much to be gained from understanding the basics and how this should affect your choice of pump.  Ultimately of course it is the task you require a pump for that should be the main determining factor in your choice.  Bore pumps, for example, will need to have the depth and volume considered very carefully, but knowing how this relates to the mechanics of the pumps available should make it much easier for you to buy bore pumps online whilst relying on your own knowledge and understanding.

In and out

If you try breathing in and out deeply, you’ll notice that breathing in requires more effort simply because you are tensing muscles to create a vacuum effect and draw air into your lungs, essentially pulling air in and pushing it back out.  Whilst, not a perfect analogy, this bears a lot of similarities to the way in which the two key different types of pump function.  Standard pumps, such as jet pumps, pull water to themselves whereas submersible pumps, like many bore pumps, push water out of themselves.  This key difference is the single most important thing to understand about pumps as it tells you of the limitations and applications that they are suitable for.

Is the sky the limit?

Traditional pumps work by lowering the pressure within themselves so that they create suction that pulls in anything nearby.  When applied to fluids this means that they will draw up a solid stream that will completely fill the intake pipe and as such have physics similar to that of a solid object applied to it.  Ideally, a pump will create a perfect vacuum which means that the pressure inside the pipe will be zero, drawing the fluid in to fill the vacuum.  However, there is also the air pressure to contend with as well as the weight of the fluid.  The more fluid that is drawn into the pipe, the heavier the mass inside the pipe becomes and this exerts a downward pressure due to gravity.  Eventually, this pressure will match the approximately 14.5 PSI of air pressure outside the pipe and the fluid will be able to rise no higher due to the balance created (this is approximately 10.5 metres for water) and negative pressure would be required inside the tube for it to continue any higher, which is impossible.

Up, up and away

By using an impeller, a submersible pump spins the fluid within itself to generate centrifugal force and then pushing it out in alignment with this force.  Theoretically, there is no real limit to how high fluid could be pushed using this method, you would simply need to have a more powerful motor and larger impeller for greater heights or more dense fluids.  So simply put, submersible pumps don’t suck because pulling has a very fixed height limit when pumping, and pushing does not.