Timing the Trevithick Dredger Engine_ 2 making the fittings
Today I made the fittings which would enable timing the dredger engine…
I needed access to the boiler for compressed air, and a temporary installation of a pressure gauge. I decided to add a valve, so that I could shut off or adjust the compressed air.
I had made a safety valve, with a lead weight, but I had no idea of what pressure the valve would release, hence the gauge. A spring had been specified in the plans, but I did not know whether it was actually required, so initially I left it out.
So, with the above setup completed, I turned on the compressor, and waited to see when the safety valve would vent.
It vented at about 20psi, a bit low. So I added a spring. That pushed the venting pressure up to 30psi. At 30psi, the engine was still not turning over.
I was expecting that the engine would move at 30psi, but that the timing would need adjusting. After an initial movement back and forth…. nothing.
The engine is still a bit tight, so maybe more pressure required, so I installed a heavier spring.
So I installed a heavier spring. Pressure rose to 50psi before venting. Still no movement in the engine. Something is wrong.
- The throttle is not working properly. Maybe the plans are back to front, or I have made the throttle back to front. I have made both of those errors in previous builds.
- The steam valve is back to front. Yes, I have done that before too.
- There is a blocked steam-air passage. Yes, I have managed that one before too.
Next steps… re-examine the plans. Do a tear down of the throttle and steam valves. If no obvious cause for the failure of movement…. call for expert help. Yep. I have done that before too.