electric boiler water pump

[nigel jones 5Participant @nigeljones5]

[nigel jones 5Participant @nigeljones5]

As a backup im thinking of adding a lipo powered small boiler pump under my 7 1/4 Invicta tender. Any suggestions or advice?

[Neil WyattModerator @neilwyatt]

Liposuction!

[Jeff DaymanParticipant @jeffdayman43397]

http://www.ebay.co.uk/itm/CARAVAN-CAMPER-MOTORHOME-VAN-WATER-PUMP-FOR-SINK-OR-BATHROOM-WASHING-/111643404617

I've used the pumps as seen in the ad above in industrial applications with success. Cold water or water-based fluids only. These are self priming pumps.

The markings on the ones I used are SZY-2014-4155 if you want to Google search elsewhere for them.

Good luck. JD

Edited By Jeff Dayman on 19/04/2015 13:54:30

[Les Jones 1Participant @lesjones1]

Hi fizzy,
This is not anything in the form of a solution to the problem. It is just to see if my understanding is correct. Am I correct in assuming the pump needs to deliver water into the boiler at a pressure at least equal to the working pressure of the boiler and also the rate of flow does not need to be much more than the rate at which the heat source can turn the water into steam ? ie. A high pressure low volume pump is required.

PS the title amused me. It made me thing the boiler was heated electrically.

Les.

Edited By Les Jones 1 on 19/04/2015 14:30:13

[nigel jones 5Participant @nigeljones5]

Hi Les, yes that iis it in a nutshell. Someone on ebay sells a complete unit for a reasonable price but I will build my own and no doubt end up spending twice what I could buy one for.

[John RuddParticipant @johnrudd16576]

http://www.ebay.co.uk/itm/Microcosm-M11-Electric-Steam-boiler-feed-pump-/161127199918?pt=LH_DefaultDomain_3&hash=item2583edf4ae

[duncan webster 1Participant @duncanwebster1]

6mm bore 5mm stroke seems a tad small even for an Invicta, but you can scale it up from the info on the advert.. Power required (watts) is (simply feed rate in cc/sec) * (boiler pressure in MPa). 100 psi is 0.69 MPa. A big pump going slowly works better than a little pump going quickly, the balls have time to get back on their seats properly. You need a bit in hand to cover mechanical losses.

[duncan webster 1Participant @duncanwebster1]

That last post is rubbish! I can say that because I wrote it. I'd forgotten that the pump is single acting, and even then has a very non constant torque during delivery. The calculation of energy input is correct, but you need a motor which will deliver a torque of piston area * pressure * stroke/2. Use consistent units metres, and pascals. Thus 10mm bore and stroke working to 0.69 MPa is (0.01^2*pi/4) * (0.01/2) * 690000 = 0.27 N.m. Then add bit for inefficiency. If you want to be sophisticated you can put a flywheel on the hight speed motor shaft, or use a multi ram pump.

[nigel jones 5Participant @nigeljones5]

Thanks Duncan – that one went for £72 !! It will not cost me that much to make my own! Im looking at a motor with 60-100 rpm, piston 1/4" but with 10mm stroke – what do you think?

Torque: 130 N*cm

• 12V DC
• 60RPM
• Diameter: 25mm
• Length: about 72mm
• Shaft diameter: 4mm

[wendy jacksonParticipant @wendyjackson]

I use a electric pump to feed my pansy. I have mounted it on the riding car.it can run at 120psi and is the type window cleaners use. I run this off a small 12v battery placed under the seat.i use a simple on off switch also mounted on the riding truck.works very well.next i sm planning to match this with a low water alarm to make the system auto.but the way things are at the moment this may take some time to sort out.michael

[duncan webster 1Participant @duncanwebster1]

Hi Fizzy

that motor should drive your pump, which has smaller bore than my sum. 130 N.cm is 1.3 N.m which is more than I worked out. Are you sure the pump is big enough? I make it 1/2 pint per minute

[Ian S CParticipant @iansc]

fizzy, I can imagine a little radial pump with maybe 6 cylinders, opperated by a cam on the motor shaft, it would only need a very short stroke.

Ian S C

[Neil WyattModerator @neilwyatt]

Posted by Ian S C on 19/05/2015 10:08:17:

fizzy, I can imagine a little radial pump with maybe 6 cylinders, opperated by a cam on the motor shaft, it would only need a very short stroke.

Ian S C

Why take the easy way out? Make a V12!

Neil

Edited By Neil Wyatt on 19/05/2015 10:19:26

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