allchin water pump

Edited By JasonB on 26/03/2010 15:39:31

Edited By JasonB on 26/03/2010 15:41:09

hi can any body tell me what cutter to buy to do the the gears for the allchin 1.5 inch. i need to know the module and no for the 15 teeth pinion. many thanks dave.

Module won't do you much good as they are 16DP gears. and for 15T you will want a No7 cutter

Check what the pressure angle is, if you already have the other gears then you will need to match the PA either 14.5 or 20 degrees.

J

Thanks Jason I've got the cutter and will be cutting the gear soon. The reason for making this gear is that i damaged the teeth when trying to bore out the centre, due to it being under size from the supplier, the hole size is to small for the key way to be cut in the gear change centre. Drawings are wong the centre of the gear is to weak to be bored out to the drawn size. Thanks once again, all the best its good to see that someone will give so much free help and advice.

Hi,

The drawings for the 6" Ruston Proctor traction engine which I am building does not have a piston water pump, only an injector and a separate steam operated Moore pump. (4" version comes with a piston pump).

I have a casting for an Alchin traction engine pump which is about the right size but I have a question about the piston design.

What is the reason for the small spigot at the end of the piston ?

Paul.

May be intended to reduce the dead water space? However, I suspect all it will do is restrict the water flow as the piston advances. Personally I think it's a waste of space itself.

Andrew

Thanks Andrew,

That was also my reasoning for the feature. I could not see any logical reason for it. All of the pump designs that I have seen do not have a spigot on the end of the piston and will make mine with a flat end unless someone can give me a good reason to keep it.

Paul.

Suppose to be an "anti airlock pin" which you see quite often on these sort of pumps. Not sure how and if they work.

The Minnie design has one but not the Fowler.

J

Quite so, although not present on the full size Burrell water pump that I've based my re-designed water pump on. The full size pump has a 'PET' cock into the dead space, which presumably can be loosened to let the air out if the pump won't start.

Andrew

The "anti-airlock pin" was a fad started by LBSC back in the early days. The theory goes that when you compress water the entrained air gets squeezed out and causes an airlock. Not a problem on full size pumps but apparently was with smaller plunger pumps used on model locos etc. Never been able to fathom the physics of the method!

That's odd? When I was re-designing my Burrell water pump there was quite an extensive discussion of water pumps on the TractionTalk forum, including one professional pump designer. At least some of the full size engines and portables discussed had PET cocks to over come airlocks and help the pump start. So, in full size at least, that rather pre-dates LBSC.

Andrew

Thank you gentlemen for the advice about pumps. I think that I will make the end of the piston flat and add a small pet cock to the top of the cover plate on the pump.

There is one on the full size Fowler which I drive for purging air from the system which works OK. The problem being that it sprayed water into the driving cabin over the operator so piped it to discharge to the side of the engine. It is used for not only bleeding air but to confirm if the pump is actually working and if there is still water in the tender tank. (Also good for spraying onlookers standing on the side of the road with water.)

Paul.