Pump Primer

There are four main types of pumps — centrifugal, trash, submersible and diaphragm — each has its own set of uses, as well as its own set of benefits and drawbacks. Read on for a rundown of each type of pump’s advantages and disadvantages.

Centrifugal
Centrifugal pumps operate off the “centrifugal force” concept and fall into one of two categories — standard and trash (more on trash pumps later).

Advantages:

• Lightweight but have a large capacity
• Typically not expensive
• High suction lifts and relatively high discharge heads
• Not complicated machines — easy to operate and repair

Disadvantages:

• Can wear out quickly if there’s not enough liquid to carry solids
• Must be supervised
• Can be noisy
• Can take a long time to re-prime

Trash
Trash pumps offer special features, such as extra-heavy vanes and wide passageways, that enable them to pump debris suspended in liquid.

Advantages:

• Moves large volumes of water quickly
• Can pass large volume of solids

Disadvantages:

• Self-priming trash pumps must be manned to ensure continuous flow of water to the suction intake
• Limited suction lift — should be as close to the pumping fluid as possible

Submersible
Submersible pumps operate underneath the water’s surface; they can handle large volumes but require little attention. They are available in standard or trash versions.

Advantages:

• Can handle large volumes and have high discharge heads
  
• Offer instant priming and can run dry
  
• No suction hose
  
• Unlimited suction life

Disadvantages:

• Not made to pump thick liquids (trash versions can certainly handle solids)
  
• If there isn’t sufficient electrical power, users might have to use a generator
  
• Can only be inspected by pulling them out of the water

Diaphragm
Diaphragm pumps are considered positive-displacement pumps — what enters the pump will exit the pump. Also called “mud hogs” or “mud pumps” because of the variety of material they can move, these pumps work on the same basic principle as a plunger.

Advantages:

• Ideal for applications where there’s a variable flow of water
  
• Can handle significant solids without fear of damaging the machine
  
• Lightweight and portable
  
• Designed for dry priming and dry running
  
• Work best in situations where there’s a large amount of trash or sludge or where there is variable seepage, or both
  

Disadvantages:

• Less capacity than a self-priming centrifugal pump, but cost about the same
  
• Limited to 25-foot head at sea level