Brushless water pump

[RalphVa]

By my calcs of hydraulic hp needed and resultant amps needed from 14 volt battery, the efficiency of the diaphragm pump is very high, probably around 95%.

Whereas, I know from working with centrifugal pumps in chemical engineering that the small ones are only about 30% efficiency. For instance, the small Hayward swimming pool pumps are about mid 30s efficiency; whereas, I have a much bigger diameter Challenger centrifugal pump on which I've measured about 70% efficiency, which is more typical of larger centrifugal pumps.

Submersible centrifugal probably range in efficiency between 30 and 70%, depending on their diameter. You get centrifugal force by pushing fluid from the middle of the impeller to its outer edge. Bigger turns out more efficient. There are extensive charts showing efficiency vs. size in our engineering applications books.

Ralph

 

[RalphVa]

Oh, an update. Tore apart one of the older 1.8 gpm Flojet pumps I have to see what could go wrong in there. Not much. There's just a rocker off the motor that works 2 diaphrams, one on the suction and the other on the discharge. That old pump was utterly clean.

So, once again I got the pump working pumping from a 5 gallon bucket and then back to the bucket with pump sitting on the FEL. Took down below to the little stream. Put suction into my receiver plastic cutout with suction valve under water into the stream. Pump would not pump.

Brought suction line up to the bucket sitting at same level as the pump. Pump started pumping. Shut off and put suction into the stream. Pumping now.

Think I've a leak somewhere in the 1/8 mile section of line I haven't used in 3 or 4 (maybe more) years. The rest of the 1/4 mile of pipe up the house is leak free. There's a definite leak about 20' from the pump at a repair joint, probably about 1 quart/minute (don't use plastic splice pieces; use only metal for 3/4" poly). Suspect I've another leak somewhere along the unused (but on surface but sometimes in some brush, etc.) section, as I'm getting nothing up here at my rain tank open to it.

Will go down and turn it off for the night and bring battery up for charging and maybe walk that 1/8 mile of pipe (drove along it with tractor before dinner) before shutting down. Then fix that one place near the pump tomorrow morning and look for more leaks.

We got a sprinkling of rain yesterday afternoon.

Ralph

 

[radios1]

By my calcs of hydraulic hp needed and resultant amps needed from 14 volt battery, the efficiency of the diaphragm pump is very high, probably around 95%.

Whereas, I know from working with centrifugal pumps in chemical engineering that the small ones are only about 30% efficiency. For instance, the small Hayward swimming pool pumps are about mid 30s efficiency; whereas, I have a much bigger diameter Challenger centrifugal pump on which I've measured about 70% efficiency, which is more typical of larger centrifugal pumps.

Submersible centrifugal probably range in efficiency between 30 and 70%, depending on their diameter. You get centrifugal force by pushing fluid from the middle of the impeller to its outer edge. Bigger turns out more efficient. There are extensive charts showing efficiency vs. size in our engineering applications books.

Ralph

piston pumps should be very good too, but very hard to find for some reason..

 

[RalphVa]

Yeah. I could not find any piston pumps run off 12v. They could be candidate for inverter to 120v IF could find one small enough. Haven't found any.

Ralph

 

[RalphVa]

Update. Repaired that splice leak with metal splice. DO NOT USE THOSE PLASTIC ONES! Had 2 splices not far from the pump, both plastic and both leaking.

NOW am getting flow up to my probably lowest level tank and barrels. Shut off all the soaker hoses. Figure by half time I can go out and open one of the slightly higher tanks and close off to that slightly lower tank and barrels. They should be near full then if I'm getting the full 1.8 gpm up here. May be now, maybe not more leaks. Wife says she's not digging in among the growths to find all that 1/8 mile of poly, that I can buy and lay out a new line if I think the present one is leaking.

Ralph

 

[RalphVa]

Filled up one 300 gallon tank and its adjacent 2 60 gallon barrels with the pump, and Mother Nature came along and contributed a 1/2" of rain, which normally fills all the tanks and barrels. Went down and removed the battery and pump. Good for maybe a week.

Ralph