Model Engine Maker

Supporting => Engine Ancillaries => Topic started by: Firebird on July 26, 2012, 08:11:28 PM

Title: A hydraulic hand pump
Post by: Firebird on July 26, 2012, 08:11:28 PM

Hi

Heres a few photos and some plans of a pump I built a while back to test my small boiler. I will use it again to test the boiler on my portable engine.

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC07289.jpg)

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC07282.jpg)

(http://i242.photobucket.com/albums/ff17/firebird_021/pump3.jpg)

(http://i242.photobucket.com/albums/ff17/firebird_021/PUMP4.jpg)

All the parts layed out on an enlarged plan

(http://i242.photobucket.com/albums/ff17/firebird_021/DSC07278.jpg)

Any questions please ask, I have more photos and details.

Cheers

Rich

Title: Re: A hydraulic hand pump
Post by: arnoldb on July 26, 2012, 10:32:38 PM

Thanks for showing your pump and plans Rich  :ThumbsUp:

Having built one myself to your plans (not as good looking though!) and after pressure testing a couple of boilers with it, I can really recommend it  :NotWorthy:

Kind regards, Arnold

Title: Re: A hydraulic hand pump
Post by: smfr on July 26, 2012, 11:58:41 PM

I read that when building the Stuart hydraulic pump, you have to be really accurate. Is it just that the piston needs to be a very tight fit to the bore, otherwise it leaks?

Simon

Title: Re: A hydraulic hand pump
Post by: chuck foster on July 27, 2012, 02:48:20 AM

thanks for the plans rich  :ThumbsUp: and as usual that is a mighty fine looking piece you have made.

chuck

Title: Re: A hydraulic hand pump
Post by: Bearcar1 on July 27, 2012, 11:00:50 AM

I remember when you built that Rich,......... NICE!  :ThumbsUp:

BC1
Jim

Title: Re: A hydraulic hand pump
Post by: Firebird on July 27, 2012, 07:24:25 PM

Hi

Thanks gents.

Simon, the piston needs to be a nice sliding fit in the bore. The piston here is stainless steel and is bang on .25 so all I had to do was carefully ream the bore. The trick is getting the O ring groove right. The O ring in this case .25 OD with .125 ID making the walls of the O ring (if thats the right term) .0625.  When turning the groove in the piston it must be slightly larger than .125 so that when the O ring is fitted it is slightly larger than .25 and therefor makes a good seal when squashed into the bore. Although the plans show the O ring groove to be .0625 wide it does in fact need to be slightly wider so that when the O ring is squashed down, making it oval in section, it has an equal amount of room to move sideways. I think I'm right in saying that O rings won't compress but just change shape. A quick search on google and you will find plenty of info re O ring groove sizes.

Cheers

Rich