Member postings for George Hughes

Hi J,

Yes, the pump has a 3/4" stroke with a 1/2" bore as it's running at 1/16th speed of the crank, so that should do the job nicely, plus because its a slower motion there should be a better pumping action than a conventional crank driven pump as the balls will have better seating.

And like this the pump just bolts on the outside of the tender and is driven by the existing wheel hub. It's an easy fit.

George

Hi J,

The drive to the axle is live from the crank, so as the crank rotates, so does the axle. The drive pins in the hubs are the disconnect so it means the mechanical water pump, whether axle or crank driven are live all the time as the crank rotates.

It looks, Dave and Alan, that you will also need an extra bush in the top of the boiler (as well as the bottom for the mechanical water feed) as the water gauge needs to be isolated from other fittings, so cannot be used as a steam feed...

George

Hello All,

Well, I have stirred up a hornets nest here, haven't I?

First of all, it is not Alan, but I am sure he is keeping an eye on things with great interest.

Secondly, the original piping was 1/4 inch o/d and 6mm has been used as the 1/4" is not readily available nowadays.

Thirdly, on the original design there was no way to isolate the boiler from the piping (the feed to the steam take-off tube, meaning the pressure gauge, safety valve and ultimately the engine) meaning that this part from Colin's reply - The water level gauge must be positioned so the lowest level is above the firebox crown and should be independent of any other fitting or manifold - is not met, but this still doesn't explain about the 5/16" (8mm) tubing.

Regarding the lowest level of water showing being above the top of the firebox crown, this doesn't seem to apply as the firebox is simply a box containing a simple pot boiler with the exhaust vent at the top, because of the unconventional design, but the sight gauge shows an at least 1/3rd filled boiler at its lowest level. It is essentially a simple horizontal, single water-tube boiler with a gas fire under the back end which should have the water level with the centre of the boiler in normal use.

Perhaps Jason's suggestion about the safety valve being restricted by the pipe diameter could be the problem?

The head scratching continues...

George

Hi Jason, Now you mention the external piping being live it makes me a little more doubtful about calling this inspector chappie over zealous.

Many thanks for that! Very much appreciated.

George

Hi all,

I'm new on here and would like to pick a more experienced brain or two.

A mate is building a PYRTE traction engine and has been told by an inspector that the steam piping needs to be 5/16" (8mm) to get by the latest boiler regs as it has not been certified so far.

The original runs nicely on 1/4" piping, so is there really any need to upgrade this piping and the necessary fittings, after all, it is around the 1.5" scale? Or is this just an over zealous inspector who's used to larger models having a hissy fit?

Many thanks in advance,

George