Klinger Reflex Level Gauges

Hi
I have another Bulleid question regarding Reflex type water gauge levels.
As I see that they where once fitted to the Bulleid Pacifics and I would like to ask why they were replaced with traditional glass tube gauges

 

From memory (I'm away from my books at the moment), they were another aspect of the original Bulleids that had to be treated in a non-standard way. On the Southern, gauge glasses were considered a driver's responsibility and they were expected to change them if necessary and attend to any leaks from the glands. The Klinger gauges, which sealed on a flat glass plate, needed fitter attention to get them leak tight. That was fine as long as they didn't leak once installed, but if they did start leaking out on the road the loco would have to be failed on return to shed while awaiting the fitter's attention, whereas even a failure with a conventional gauge glass could be replaced by the driver at a convenient time.

Basically they were replaced in the cause of standardisation, but this doesn't necessarily mean there's anything wrong with them in the context of modern preserved line operation.

 

Another possibility was that the Bulleid boilers were originally pressed to 280 psi and that is getting to the practical limit of a conventional gauge glass. Klinger fittings are generally used on high(er) pressure boilers in industry and it is quite possibly the reason that they were originally used. Reducing the pressure to 250 psi did away with the need for them and allowed the use of standard fittings..

 

That perhaps although I have seen tube glasses use on higher pressures. But as suggested a high skill level needed and replacement glasses are/were not cheap.
In my experience of using and maintaining both types the Klinger is far superior but
The glasses are expensive and require specialist knowledge to fit and change.
Any left over jointing material on the surfaces and uneven torque on the fixing nuts will crack the glass as it heats up and we had a hard and fast rule to let the glasses 'soak' up to working temperature after putting back on steam drums/vessels for 48 hours.
Apprentices were allowed to change tube glasses once they had been shown how to do it and you soon learnt not to overtighten the packing nuts and have the glass crack on you.
Klinger glasses were only overhauled by seniors and they oversaw any apprentices being trained on them like hawks. Although they failed/cracked safe ( and we operated our valves with remote hand chains some 4 stories below the actual gauge location) the experience of having an 80bar boiler Klinger gauge crack and fail on you is never forgotten and bad enough but I would not like to have a tube glass one fail at 80bar.

Another reason may have been that we only blew out gauges once a week to preserve the sheet of very thin sliver of mica that protected the glass from the water treatment chemicals used. With 2-5ppm of distilled water quality used as make up we had no fears of scale blocking up the gauges but it is a very different scenario with low pressure loco boilers fed on untreated raw water.