Simplex water gauge connections.

I am considering buying a Simplex form a well know locomotive dealer and have a question re the water gauge connections on this model, photo attached.

A friend pointed out the unusual way the top connection is taken from the steam manifold instead of the usual way of a connection to the top of the boiler.

Is this an advantage or will it cause surging of the water level or in fact prevent it?

It will not read water level correctly, as any steam flow to blower, injector etc will cause a drop in steam pressure in the manifold and the water level will rise in the gauge glass.

Thanks for response. Is this a problem as the use of blower and injector would be of short duration. It is during actual running that would be a problem if this occurs. The usual way Simplex's are connected is to take a connection to a separate connector to the left of boiler manifold at about the 11 o'clock position. This would be into the steam filled area at the top of boiler.

Blower is not necessarily short duration, on our track people seem to leave it on down the hills. Using the injector would be interesting as you wouldn't know when to turn it off. I'd speak to your club boiler inspector before parting with any money.

I second Duncan's suggestion above to get in touch with your club boiler inspector as there are a few differences between this boiler backhead and the published drawing - the clacks have been blanked off and two new ones fitted lower down and the water gauge should go to a fitting on the top of the boiler not to the turret. Also there appears to be an additional blank behind the water gauge. These are possibly only trivial changes, but it is better to make certain you can certificate the boiler before you buy as it is not strictly to drawing.

If the lower clacks have been added later he may wish to check they have been silver soldered in place.

It is recommended these days that steam feed to water column is a dedicated feed and not tapped off any manifold or shared with any other function. There used to be miniature traction engine designs where the water gauge came off the manifold and as Duncan says when there was a high steam demand on the manifold this lowered the pressure in the manifold and 'lifted' the water giving a false higher reading. Having said it is recommended I can't think of anywhere off hand where it is mandatory that the steam feed to the water gauge is independent, it might be in the new boiler code and I missed it! I have been on full size loco's with independent feeds and have seen the water in the glass lifted up to 1" when the loco was working hard and the steam demand high so even a seperate feed is not a cast iron gaurantee!

FWIW there are designs out there that have on the drawings the water bush for the gauge set below the firebox crown, 4" Foster is one that comes to mind. Some commercial boiler makers are producing boilers to the drawing. This means that when the water is on the bottom nut the firebox crown is dry! This is contrary to the boiler code and normal common sense.

End of the day it depends on how thorough the boiler inspector is and how far he is prepared to excersise his discretion, I have seen several boilers in the past that have previou certificates with this type of issue. I imagine this loco coming from a dealer will come with a certificate? That being the case someone obviously thinks it's OK.....

Paul.

It is in the new code, but only 'where practicable'

However the comment is in the preamble 'Before any testing is carried out on a boiler it must satisfy the following conditions' so presumably it could apply.

6.6 Boilers shall be fitted with at least one water level gauge which where practicable is to be fitted to the boiler independently of all other fittings, including the manifold. Where practicable the fitting of gauge glass protectors is recommended.

(Boiler Test Code 2018 Vol 1)

Edited By Nick Clarke 3 on 22/12/2018 19:53:23 for typo

Edited By Nick Clarke 3 on 22/12/2018 19:54:49

The boiler code in Australia states that "Water gauges shall be connected to the boiler independently of all other fittings, including the steam manifold".

The pressure at the top of the water gauge will be lowerred if steam is taken from a common manifold while the pressure at the bottom will remain constant. This will cause the water level in the glass to rise and give a false reading, possibly exposing the boiler crown when you thought that it was coverred with water.

Paul.

Edited By Paul Lousick on 22/12/2018 22:03:48

Thanks to everybody  who responded to my query.

I have been thinking about the problem and wonder if by restricting the flow to the upper gauge connection by introducing a brass tube with a very small hole, rather like a carburettor jet, the effect would be to dampen out the fluctuations to make the gauge useable. Perhaps members could give their views on this. Initially I realise that this hole would have to be kept clear of obstruction i.e lime scale, however I use rainwater.

Edited By Bryan Cedar 1 on 23/12/2018 17:18:52

For the water gauge to show the correct height of water in the boiler, the pressure on the water in the glass must be exactly the same at the top and the bottom. Any restriction will give a false reading and could lead to over filling the boiler and priming. (and damage to steam chest and piston) or low water in the boiler (Boom !!!).

Part of the procedure when firing a boiler is to do a water column (gauge) check, where the bottom water cock is closed and drain cock opened. Steam should exhaust thru the bottom cock. (similar test for the steam cock). This procedure is a safety check and also cleans the hole thru the cocks.

**LINK**

The person that built the boiler in the above photo probably piped the water gauge this way because it was easier than what the drawing called for. This was also probably done in ignorance. Both ends of the water gauge should have their own separate fittings completely independent of all other fittings. As you can see in my photo, the top end fitting of a Simplex water gauge requires more than just "piping it up to the steam manifold"

The water gauge shown does not have isolation cocks for the steam and for the water conections. How do you isolate the gauge if the glass breaks ? Also no glass protectors.

Isolation cocks are required so you can independently check if the ports are clear or blocked. If blocked they can be cleared while the boiler is still under pressure. Without isolation cocks, the boiler will have to be shut down.

Paul.

Edited By Paul Lousick on 31/12/2018 08:56:19

The water gauge shown in David's photo appears similar to that drawn by Martin Evans. Perhaps, like LBSC before him, he considered its simplicity outweighed its disadvantages. As drawn, Simplex doesn't have any draincocks either, removing any need for tapered cocks on "A simple powerful engine that is suitable for the beginner who requires ease of construction".

Brian

Indeed, my water gauge is made to the drawings of Martin Evans. It is made exactly like most conventional water gauges for 5" gauge locomotives. There are no isolation valves to be sure, and, neither does the one shown at the beginning of this thread. This is typical for this size water gauge and is not required. What is required though, is the blow down valve, clearly, both of these gauges have this.

What to do if you break the glass? Put a rag over the smoke stack and turn on the blower, the fire will got out quickly. If you break your water gauge glass, you will have to put out the fire in any case. I would not want to reach in close to a water gauge to operate miniature valves while steam is coming out right next to them.

The boiler will have to be shut down with or without isolation valves as you now have no water gauge.

I'm still not sure how folks break their water gauge glass. I have shoveled lots of coal into my fire box and do not even come close to touching the water gauge. I suppose anything is possible.

David

Hi David

Thanks for your input to my query. I have shown the picture of m intended purchase of the Simplex to my boiler inspector. He has accepted my suggestion that if a "T" piece is fitted directly to the boiler 1/2" bush that connects to the manifold this in turn directly feeds the top water gauge connection before the manifold connection, the result will be satisfactory owing to the large size of the bore of the bush. the original connection will remain for support but will be blanked off.

Hi Bryan,

If your boiler inspector has signed off on your suggestion of a T in the supply for the manifold, then, that is the final word on the subject, at least as far as getting your loco running on your club track.

A few things to do and notice, as others have suggested, that the level in the glass may be affected by other accessories connected to the T. Note the water level in the glass with any of these accessories turned off, like the blower or the injector, and see what happens to the water level when they are turned on. As long as you are aware of what is going on, you should be fine. Just don't forget that the water level may be something different than what is shown.

David

Thank you to everybody who responded to my query re the Simplex water gauge connections.

Unfortunately it was all in vain as the selling company whose initials are S R S failed to respond to my enquiries on three occasions. I have therefore decided not to proceed with the purchase. Probably a good omen as I have been warned off this loco.