Whats the name of the pump, often for bilge, which kind of sucks, then blows the liquid out?

Hi,

Yes.
Its similar to a vibration pump (like in many espresso machines)
and one can replace the diaphragm with a piston.

The max. pressure is determined by the internal spring. (may depend on type)

Klaus

Bilge pumps are usually slow running membrane pumps, operated by a PMDC motor with eccentric drive.

I have a small centrifugal one that runs off 12V.

reciprocating pump?

Brian.

Thanks, i must admit, this one offers long, maintenance free life...

...unfortunately datasheet doesnt say whether it can handle air in the tubes, and whether it needs to be submersed in the water or not. Also, it looks like it may struggle to pump water up 2 metres even with the tube being low diameter?


...its offered at 12v and 24v...but as we know, one of those voltages will have more availability of these type of pumps...from what EasyPeasy says, i am thinking to go for a 24V system voltage.
Would you agree?
(also bearing in mind the solenoid aswell)

Do you understand what the feature "self-priming" stated for CMP40L series means?

oh thanks, "self-priming" by definition, means that it can handle air in the tubes, would you agree?

A non self priming pump would need to be totally immersed in the water......i dont know what would happen if a non self primer tried to start if it wasnt submersed in water.

The above pump, being "self priming" would therefore not be immersed in water...indeed, it couldnt be so.

Non-self-priming pump could overheat in air or simply pump nothing. Any good answer deserves better specs.

The brand name Rule pump is the most common pump in the area I live. They are centrifugal pumps and mostly used in small sport and commercial fishing vessels as submersible bilge pumps. The whale pump looks to be a diaphragm pump. On the 120’ vessel I’m on we have 1 hp 3 phase centrifugal pumps. We also have 1” diaphragm pumps for oil changes and at times pumping bilge. From my experience the diaphragm pump draws water reliably but discharge is not as constant or smooth. It will also quickly draw water even if there is air in the suction line initially. The centrifugal pumps are usually fitted with a check valve on the suction to prevent getting air locked and back siphoning. They can sometimes draw water without a check valve if the pump suction heighth is very close to the water heighth. But you waste energy up until the point it gets primed.

In post #6 you stated it might struggle to pump up to 2 meters even with small diameter tubing. I could be wrong but a smaller diameter tubing would make it more difficult to pump than a larger diameter tubing because of friction losses. I don’t think the diameter effects the static head pressure.