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A Part Finished boiler
PYRTE - Ready For Action


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PYRTE

First Trials In Steam...

OK, you’ve got her sat on your bench and you’re itching to get a head of steam up for your first trial run.

 

This takes me back to my first attempts when eagerness over-ruled common sense.

About a week after a lot of trials and testing when I'd tried her on air on my bench as can be seen here on Youtube (you'll notice this was Version 3 with the cast iron cylinder and the wobbly flywheel), I half-filled her with clean water using my hand pump and used a blow lamp under her belly to provide the necessary heat (this was before I’d even attempted to install a fire).

With the regulator shut off, I was watching for any signs of the pressure rising on the gauge, not really thinking that I hadn’t vented the system to allow the steam to warm up the piping and cylinder, so any steam produced was pushed along the piping towards the cylinder and was simply condensing in the cold piping and especially in the cold cylinder.

After around ten minutes of the blowlamp going full belt, I noticed there were bubbles coming from underneath the cylinder block (where I had shifted it off the bed plate a week or two before, but never cleaned off the sealing compound properly, or even trimmed the burrs where I’d drilled through the top bed plate that the cylinder block sits on, thinking at the time that it would do for now, and I’d sort it later), so the pressure was building up, although there was still nothing showing on the pressure gauge.

In other words, there was condensate sitting in the steam space below the cylinder and the low steam pressure was forcing some out in the form of bubbles mixed with oily water, regardless of no pressure showing on the gauge.

After a further three or four minutes, with bubbles still being produce and still nothing on the gauge, I tried turning the flywheel in a forwards motion, hoping to allow the steam to get in the cylinder and maybe that way start the engine and hopefully clear itself of any excess condensation and the oily sludge it was producing.

That was a big mistake.

Firstly, there was not enough pressure to drive the motor as the water was maybe just above boiling point, and secondly, the condensate made its way into the cylinder and stopped the travel of the piston dead in its tracks.

It was then I realised I should have vented the cylinder to get her warmed up progressively first, but like a dope, I didn’t.

It came to me then that I would have to remove the cylinder block and make good the seal underneath, so I removed the heat, and while I was waiting for it to cool down, I tried turning the flywheel and got it moving a little as the piston pushed water past the seal for the piston rod within the trunk guide, so that seal needed sorting.

Next, the penny dropped with a GREAT BIG BANG.

It dawned on me that I had no way of draining the water from the boiler. I was in such a rush to get her steamed up that I left the drain cock off and simply put a blank in its place.

In the end I had to wait for the engine to cool right down, open the cylinder block drain, and support the engine on its tail end with the connection between the hand pump and the check valve undone, as I had the pump temporarily sat on the bench, along with removing the drain cock blank just to drain the boiler. And even then the cylinder block and boiler barrel still contained water.

My shed floor and myself got soaked...

What a rigmarole! And all because I didn’t put the brain in gear before jumping in.

So I ended up trying her out on air pressure once again and found she ran beautifully after 10 lbs pressure on the gauge on my compressor, but there was still no sign of any pressure on the boiler’s pressure gauge. This was all down to a rubber washer I’d used in the piping to the pressure gauge. I’d tightened the nut just a nadger’s too much and the pipe was blocked by the washer, so in the end I got rid of the rubber washer and she held pressure beautifully anyway.

It can be very frustrating when you do a lot of things to your engine and you have to find out which one is causing the problems.

 

SO...

I suppose I’d better take you through exactly what should happen when you come to fire up your own steam engine for the first time.

The following is a sequence of events needed for PYRTE, although this applies to many steam engines other than an oscillator, that you need to go through. I am assuming you have had her running on air first before you go over to steam, and not pulled bits off and replaced them like I have done in the past, so you know she’s a runner:
  1.  Make sure your steam engine is sat level.
  2. Open up the cylinder block drain valve.
  3. Make sure your blow-down/boiler drain valve/tap is shut off.
  4. Push the regulator fully into the off position.
  5. Make a point of removing the two driving pins from the rear wheels.
  6. Rotate the flywheel by hand through a full revolution in forwards. This is all before the heat is applied.
  7. Top up your water reservoir with clean water and begin pumping with your hand pump, filling the boiler barrel so that the water level is just showing on your water gauge.
  8. You can now light the gas and begin the lubrication while she’s warming up.
  9. Make a point of oiling any moving parts to avoid friction (ordinary motor engine oil is fine).
  10. Drain any water out of your displacement lubricator and top up with steam oil. (Don’t be tempted to use ordinary engine oil for this as it gets far too thin at the temperature your steam engine works at and forms a sludge, barely doing any required lubricating.)
  11.  Once neat steam starts to jet out of your cylinder block drain valve, allow it to continue for a further minute, that way allowing the cylinder block to become thoroughly warmed up, then shut it off.
  12. This allows the valves to restrict the steam within the engine and once the pressure rises on your gauge to 10 lbs, then pump in more water to half fill your boiler barrel.
  13. Turn over the engine in a forwards direction a little by hand using the flywheel. This allows just the smallest amount of steam to pass into the cylinder owing to the valves not being shut tight from lack of pressure.
  14. When you have around 20 - 25 lbs on the gauge, then open the regulator slightly and spin the flywheel forwards to set her in motion.
  15. Open the cylinder drain off valve a little to remove any condensate that may have loitered there and then shut it off again once there is no sign of water coming out of the valve, say after a couple of dozen revolutions.
  16. It is then simply a case of letting the steam pressure build up to normal working pressure, but do lift the needle on the safety valve (with pliers) to make sure it vents steam and is not blocked up.

It is suggested you run her for around three or four minutes in that position, using the regulator to control the speed of the engine, allowing the pressure to build up fully and not forgetting to keep an eye on the water level, before you replace one or both of the driving pins in the rear wheels and begin enjoying the pleasure of driving your own home-built traction engine.

All in all, the time taken to complete this process will be around ten to fifteen minutes.

At first start-up, if your engine is new and the regulator fails to control the speed properly owing to the faces of the valve being rough, then a little judicious braking on the flywheel may be in order. The roughness should wear down quite quickly plus the thicker steam oil will soon make its way between the two surfaces, adding to the sealing properties needed.

I found that for the first five or ten minutes of actually running PYRTE on steam, my regulator would not stop my engine from rotating, but this was easily overcome as the valve surfaces got oiled up and bedded in, and then everything worked smoothly.

It took around a week of regular part-time running (maybe two or three hours in total) before my regulator was fully operational.

The speed, or boiler pressure, can be controlled by either the regulator or the gas pressure, that way making the burner work harder or lesser. Also, adding cold water reduces the pressure a little, although this is really negligible if you try to keep the water level at half barrel height.

 

I hope this gives you an idea of what’s needed when you come to run your own version of PYRTE or any other live steam engine you may have.

 

Happy steaming...

George




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