Selecting a pump & solving your pumping problems

Pump Fundamentals
A pump is a way of moving a fluid from one place to another. You should consider the following:

1/ The most important are the characteristics of the fluid being pumped eg is it a Water, Acid or an Oil pump that you need. This will tell you what the pump needs to be made of.
2/ The vertical height after  the pump to the destination is called the head. The height before the pump is called the lift.
Not all pumps can lift well and none will lift more than 30ft . The ones that lift well are called self priming.
Note : Long lengths of flat hose are like adding more vertical head ( height after the pump). Add 1metre of head for each 10metres on the flat.   
3/ The last is how fast you want to pump. ie the volume of liquid pumped in a certain amount of time. This is described in the details for a pump as litres per minute (ltrs/min) or something like gallons per hour etc and always assumes no lift and no head to reduce the volume of flow.

Illustration of a pump showing lift and head

The barrel has been cut away for illustration purposes

Pump lift and head
Pump Selection
Start by noting what you are pumping. If it's water then you need a manual water pump or electric water pump. Ensure that you use a pump that will not rust. If the fluid is a chemical then you need a chemical hand pump or an electrical chemical dosing pump to ensure that the materials the pump is made of will be compatible with the liquid being pumped. You also need to consider how thick the liquid is. Thick liquids take more effort to pump but you should not assume that they are also more difficult to pump because very light liquids have their own problems. Air and gases can be pumped but they are very thin and need positive displacement pumps. These are pumps where a space is made smaller and then larger with valves in order to force the fluid to go one way through the valves. A human heart is one of these type of pumps ( but not many people fall in love with a mechanical pump).

There are different types of pumps for different situations. You will find pumps classified by application and by type ie:
Marine bilge pumps, some times called  bailer pumps ( in under deck or bulk head mounting configurations ) where the pump can withstand salt water or ATEX approved where it might be for an explosive atmosphere.

Types of Manual hand pumps include:- Piston pump - ( positive displacement with good lift and head) sump pumps are a good example of this type of pump or tubular bailer pumps where more than 2 Litres is to be moved.
Pressure test pumps are high pressure low volume forms of the above, usually in 25Bar, 40-50Bar and 80-100Bar maximum pressures, for testing closed systems like central and underfloor heating.
Semi rotary pumps like the K series wing pumps are a form of piston pump with a curved piston.
Diaphragm pump - (positive  displacement with medium lift and head).
Chemical transfer pumps are often diaphragm pumps.
Submersible Impeller Pump - poor ( if any lift) and variable head depending on volume pumped.
Rotary barrel hand pumps are a manual form of the above often used for oil transfer. The electrical fuel transfer pumps will also do this.

How much fluid do you want to move over what time period? This is called the Volume. This is usually expressed in litres per minute but it can be gallons per hour or even cubic metres per hour. Let's take an example.
You want to pump fuel oil or diesel ( in this case a fluid that will not cause rust) etc from a barrel, sump or tank. Say the lift is less than 1 metre to the bottom of the barrel. Say the head is less than 1 metre to the can or vehicle. You want to fill the can or tank up within a few minutes. Lots of pumps will do this sort of thing. If you are happy to do it a little slower, a cheap rotary barrel pump is a good example.If you want to go faster a Patay BE45 will transfer 45L per minute. These Patay hand pumps are famous for their longevity, some lasting 20 years or more. What if the tank receiving the fluid is considerably higher ? A Semi rotary pump as in the K series Wing pumps might be a good idea. Another example, only this time the fluid is water of a large volume and it may have some solids in it when emptying cess pits or manhole clearance .... you may want to water an allotment or garden. Or use a pump for moving water for flood control . All these applications follow this general example :

The less expensive rotary pump, which is very good for Oil, is not a good idea as it will rust inside and it might rust up solid. A more expensive aluminum version would be needed. For this job you would be better off with a larger diaphragm pump on a base plate. These are called Site pumps, the most common is the DD120 and are portable pumps capable of pumping at least 120L per minute or over 1000Gallons per hour. These are the same pumps used on garage forecourts.
You can use smaller pumps but as a rule of thumb you should buy a pump that will pump the volume of fluid you want to pump before you get tired say in 10 minutes. If the pump says it pumps 1L per minute ( by moving the handle backwards and forwards for that one minute ) you should use it for pumping up to 10L at a time. If you want to pump more, use a bigger pump It is a good idea to buy the lowest cost pump for the situation. But if you buy too small or cheap a pump for a job this leads to poor performance and breakdowns. The inexpensive pumps can't be expected to last as long as the more expensive more durable ones.

Further details
Its important to have the right type of hose connected with good quality jubilee / hose clips . (On the lift / suction side the pipe below the pump)
You need good quality suction hose. If you don't, the vacuum will collapse the pipe and the pump will not work. If you have an air leak on this side of the pump the pump will not work . If you are likely to pick up solids that will jam or block the pump you should use some sort of filter, these are sometimes called strum boxes. Service kits don't contain all the spare parts. The better manufacturers like Patay and Grosvenor pumps would be able to supply you with any spare parts you might need .