Tornado

I didn't take any pictures of this area myself whilst looking over the engine in the shed today, but there's now a valve on both sides - the fireman's side looking more angled than the driver's I think...for reference here's a screenshot from the GCR Official youtube channel when it was off-loaded.




Setting aside the current issues around the overhaul and the management thereof, today was the first time in its visits to the GCR, that I've had the opportunity whilst volunteering there to properly have a look round the loco close up and not just as a lineside spectator or quick nose round pre/post-shift. It's a marvellous piece of specialised engineering excellence that as a 90s child I'm extremely glad had people willing to put the time, expertise, dedication, blood, sweat, tears and money into recreating.

 

I imagine 35028 has an Everlasting Blowdown Valve mounted on the middle of the throatplate. With an operating rod to a handle on the outside. Like Bulleid Pacifics seem to have standardised on.

The Everlasting Valve Co is still going:-
https://www.everlastingvalveusa.com/boiler-blowdown-valves/

 

I'm wondering what the procedure is for using it. As you say, if you do the blowdown with nothing on the end, you have hot water and steam emerging just inches away from where you are standing; and which would blow out all over the motion on that side. But if you attach a conventional hose to take the water away, I wonder how you stop the other end from flailing about?

There must be a safe procedure for blow downs, but I've never seen it done on that loco to know what it is.

Tom

 

Are we getting confused between blow-off and blowdown valves?
On all the Standard locos the blow-off valve is situated in the centre of the lower throat plate and is operated remotely by levers. It is also fitted with a silencer.
The blowdown valve is fitted to a flange welded to the radius of the firebox back head on the fireman's side, about level with the height of the gauge frame.

 

Now I am definitely confused. What you have just described as a “blow off” valve is what I’d call a “blow down” valve; it’s what we would use for a daily blow down. As you describe it, the operating position is remote from where the water / steam actually emerges.

Tom

 

Tom, the titles are stated on the drawings.

 

Possibly varied by company though?

In any case - never mind the names, what about the functions? Surely regardless of what you call it, a valve sited just above the foundation ring is there to do the daily blow down. So I’m curious on how you do that on Tornado.

Tom

 

Now I’m confused too. LMS locos had the sort of backhead valve you describe, roughly coincidental with water level. I think these were designed to open when the fireman’s side injector was on, and the idea was to remove any scum / foam off the surface of the boiler water. The foundation ring valve, though, has always been known as a blowdown valve in my experience, both in the UK and South Africa. However, I can find evidence of both functions being described as ‘blowdown’ on the web.

 

I think there is some confusion over terminology coming in here. All boilers need to have a boiler drain; I think that is fairly obvious. However, some loco boilers are fitted with a blowdown valve, something that is almost universal on industrial boilers. Its primary purpose is to keep the TDS (total dissolved solids) at an acceptable level. If the TDS gets too high then the boiler water starts to foam, leading to priming, which is carry over of boiler water into the steam circuit and into the cylinders. TDS usually becomes a problem when boiler water treatment is introduced but can also depend on the source. The Southern were early users of water treatment and thus the practice of blowing down the boiler so remove or more precisely reduce, the TDS. As has been mentioned above, I think Bulleid pacifics were fitted with a blowdown valve by the Everlasting Valve Co. I'm not sure if other locos were but I know several locos have been fitted in preservation. These valves are at the low point of the boiler and can also act as a boiler drain.
@std tank has mentioned another valve which is generally situated on the boiler backhead and refers to this as a blowdown valve, which it also is. However, in industrial boiler terminology it would usually be referred to as a scum cock. Both this valve and the bottom blowdown valve are there to reduce the TDS but do it in slightly different ways although both remove water from the boiler. When the boiler is in operation and supplying steam the concentration of solids is at the highest near the surface of the water so this is a good place to remove some boiler water. Ideally, this wants to be a constant removal of a small amount and this is what this valve does. It is arranged to open when an injector is being used, a feed being taken from the boiler feed water, the pressure of which causes the valve to open. However, this continuous blowdown valve cannot be used to empty the boiler so a separate boiler drain is required. The bottom boiler blowdown works in a slightly different way. It is usually a relatively large valve and will get rid of a lot of water in a short period of operation. On locomotives it is invariably a manually controlled valve and is opened when the loco is stationary. Because the loco is stationary, there is no demand for steam (unless the safety valves are lifting) and, when there is no demand for steam there is little turbulence in the water and the solids will fall out of suspension and settle at the bottom of the boiler. Thus, the usual practice with bottom blowdown valves is to open the valve for a few seconds then close it for a few seconds. This has the effect of agitating the water and moving the solids off the bottom. The valve is then opened a second time for a longer period to get rid of the solids in suspension. If you are struggling to understand this just think of a bowl of water in which there are a lot of fine particles. If the water is not moving these will fall to the bottom and form a sludge. If you then put your hand in and stir it all around the particles will be picked up and suspended whilst ever it is being agitated.
All this doesn't explain why Tornado has blowdown valves on either side of the boiler at the bottom and how they are intended to be operated. If used for blowing down I don't think a flexible hose would be used for the reasons Tom gave. It would be possible to fit a pipe using fire hose couplings which could divert the blowdown water to a safe place. However, the thought of being stood next to such a coupling in such circumstances doesn't exactly thrill me.

 

Could it be that they are not intended as blow down valves as such, merely drain valves, and the hose fitting is there so that the water can be directed to a suitable, environmentally friendly disposal outlet - perhaps more necessary now when such a loco finds itself in places not designed for steam locos?

Steve B

 

I have a recollection going back to the mid-1960s of 'Everlasting' blow-down valves being fitted to the Spanner Mk. 111 train heating boiler as installed in the D1500/Class 47 Diesel-electric locos.

 

It wasn’t like that on the original A1s (not my picture)

 

It could well be the case but why two of them? Or have they simply changed the side that it is on? And why not stick to something more akin to a tradiional boiler drain rather than that ungainly arrangement? Just been looking to see if Tornado is fitted with a continuous blowdown but it doesn't look to be the case. If they aren't practising blowdowns I would have though that it is likely to require a water change every 6-8 steamings.

 

A couple of photo's taken in S/Africa .Class 24 and a 19d blowing down. Edit .Just had a look at all of my S A photo's and 3450 The Red Devil has the blow down valves on each side

 

It is not realistic to put smaller wheels (P2) on Tornado ,but most UK express locomotives got front bogie wheels of 38 inch/960mm or greater.
The german started building 03 Pacifics with 850mm bogie wheel and put 1000mm wheels on later pacifics.
Was it a question of better guidance or less wear?

 

Surely, to my mind anyway, given the issues we know of with the foundation rings, this is a measure to remove more deposit, more regularly. Two valves mean you can blow down from either side, but also, blast deposits out with clean water when the boiler is cold. Inject at one side and drain from the other, then reverse.

This is a guess, but, we do know found rings have not been the best on this boiler, or any loco steam boiler for that matter.

 

You don’t do washouts through the blowdown valves. That’s what the mudhole doors and washout plugs are for. (On each side).

If the devices shown are for the daily blowdown, I can’t see how you use them safely. If they are simply for draining the boiler when cold, I can’t see why you need two.

Tom

 

In order to accomodate the problem reducing the wheel diameter to say, 2 Metres dead and adjusting the suspension to accomodate the new position of the bogie blocks post the drop is likely do-able, but suspect that would require the thinner wheel rim design to need re evaluation, and if un acceptable, 6 new driving wheels is no small expense and perhasps better to alter the firebox next time round
Putting 6ft 2 wheels on Tornado would require a rebuild into an A2, both very expensive and self defeating would not be popular with those who contribute. ..

Ha just remembered these things have Cartazzi mounted rear axles and there maybe very little available potential to drop those even by that amount