Can't help with the steam engine, but this may help with posting pictures.

Rob

Good luck with your search. I worked the engineering industry for many years and parts got nicknames that would mean nothing to people outside of the company. Stick insect, elephant trunk and donkey ears for example. You only need to think about grass hopper engines and stork leg engines to realise it is an old and continuing practice. The military is also good for jargon, look how the Huey or the jeep got named.

Martin C

Hydrostatic tests need to be something like 10% above the system safety valve release pressure, can't remember exactly how the Pressure Equipment Directive (PED) is worded I stopped worrying about it when I retired. The issue for boilers is that they work at higher temperatures than is used in the test fluid so some allowance probably has to be used to make the test suit working temperatures.

The pipe pressure test system where I worked had a water treatment plant to remove corrosive salts from the town water supply. The pipe being tested was fitted to the rig and filled with treated water then capped off (or suitable bosses were plugged if available) at the top where the air escaped as they were filled from below. The water pressure was then raised to the required pressure with a pressure intensifier (air pressure on one side of a piston water on the other, different areas so pressure was increased on the small area side) and the water supply locked off. The system was then left for up to 30 minutes to allow temperature stabilisation. At the end of the stabilisation period pressure was monitored with electronic pressure gauges and any leak was apparent due to small leaks causing large drops in pressure. The pipes were also visually inspected during the test as any leaks would show by the appearance of water on the surface or at joints. There was also a mobile system for taking to locations as required. You could also buy (if required) high pressure hand screw driven piston pumps to raise the water to the required pressure (imagine a medical syringe being operated by closing a vice on the plunger). This system was 800psi for the static bench (old design, label on it stated this figure) and a mobile system that went up to 30,000 bar for really high pressure parts such as hydraulic torque wrenches.

In a previous job I also spent some time calibrating and checking pressure gauges with a dead weight tester that had a hand screw driven pump to raise the pressure required.

Martin C

Hi Alan

If your loco has the same valve gear as the one in this photo I found on liveauctioneers.com you may find the naming of parts to be a problem as it doesn't resemble full-size practice but appears to use a slotted rod like John Turner's "Caledonia" to rock its expansion link.

I would suggest testing the operation of the safety valve before testing the boiler. If you fill it completely it should start to release water long before reaching boiling. Mark Horovitz says in "A Passion for Steam" and online that his oscillating example runs at 10 psi. Perhaps you could contact the person who posted this video on YouTube earlier this year to find if he can give any advice?

Brian G

Edited By Brian G on 28/10/2020 11:39:04

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