Here is a list of all the postings mick H has made in our forums. Click on a thread name to jump to the thread.
|Thread: boiler water window|
Be assured that your comment was not interpreted as negative or critical.......but it
did spur me on to get things tested ! Thanks, again.
Having sown the seeds of doubt by your queries, I carried out a hasty trial of the water window and it performed probably better than I could have wished. The visible window is 12mm in diameter and the meniscus showed as a bright line...about 2.5mm deep....against the darkness of the inside of the boiler. In this sense the darkness of the interior is advantageous. When the boiler is full there is, of course only darkness but as soon as the water level drops within the range of the window the meniscus is quite apparent. No problem with bubbles etc.
In my limited experience in the small gauges in which I work, I would suggest that this is a far better water level indication than I have ever had in the quarter inch type gauge glasses in the conventional set up.
Once again, thank you for your interest.
|Thanks Gordon. I live in tractor country and will make enquiries|
My only confidence is derived from the fact that several commercial manufacturers use a water window system. I am aiming for simplicity as this model is being made for a seven year old, albeit it will only be used under Dad's supervision. The window is 20mm in diameter and will hopefully show if and when the boiler water level falls to about one third of capacity.......as the boiler is gas fired, I am hoping that this will be an effective failsafe indicator. Only trials will determine how effective it will be in practice. I am reasonable confident that there will be enough light to show water level.
Thanks for your interest.
Thank you for your advice Rob, Jeff and Ian. All of it was useful and gave some good leads one of which led to Piper Glass of Watford who were able to supply me with toughened glass lenses and actually sent them to me for free!
It is possible to get Wilesco spares but their windows are too big for my application.
The watch batteries site mentioned by Rob gives a comprehensive selection of toughened glass lenses which I would have used if I had not come up with Piper.
Thanks for your advice on polycarbonate Jeff ........an experiment with live steam could have proved disastrous.
From what I can gather toughened glass is cut to size and is then undergoes a toughening process. My enquiries have revealed that pretoughened glass is available as a product called "Borofloat" which can be cut and shaped like ordinary float glass but I have not been able to track any down so far.
I am constructing a steam powered fire engine for my grandson and as a
variation on the glass tube type water gauge I would like to incorporate a water window in the boiler backhead.
I propose to bed the lens on a silicone "O" ringand sandwich it porthole style between the base which is silver soldered into the backhead and a cover secured by six 6 BA screws. The circular lens has a diameter of 20mm but when the cover is in place the net viewing window will be 10mm. The lens is therefore supported all around by 5mm .
The boiler will have a working pressure of 50psi at which pressure the water will be at a temperature around 150 degrees C.
I have fashioned an experimental lens from 2mm picture glass and tested it to twice working pressure = 100psi.
I have considered using polycarbonate but 150 deg.C is becoming quite close to the deformation temperature of polycarbonate.
Can anyone advise me as to whether ordinary glass can be used in this application. What do Beck etc use in their locos fitted with water windows?
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