water level in a boiler

[R4_GRN]

can anyone tell me if the water level gauge in a boiler contains the same pressure as the boiler? seems dangeous to me or is the square glass around the glass tube a safety device in case of the glass breaking?
Does the glass break often?

 

[t o m]

They are under pressure but I'm not sure if it is the same as the steam pressure. They can wear around the fixings causing them to break. The glass casing is there for protection if it did break but it also protects the sight glass from damage.

 

[themiller]

Yes, the pressure in the gauge glass is the same as in the boiler. This is proved when "blowing down" the gauge glass to prove it and the water comes out as steam. You're right in your conclusion that the glass around the tube is for safety - both for personal safety if the pressurised tube fails and to protect the tube. If you examine the protective glass, you'll see that it's quite thick.

 

[Zoidberg]

Are there not constrictors fitted to ensure against massive discharge through a broken gauge glass?

 

[E&W Lucas]

Are there not constrictors fitted to ensure against massive discharge through a broken gauge glass?

Yes, ball valves fitted on the water side, which should more or less seal it on a glass breaking. Life can be entertaining when one fails to seat!

 

[Zoidberg]

Yes, ball valves fitted on the water side, which should more or less seal it on a glass breaking. Life can be entertaining when one fails to seat!

Thanks for confirming that - and I can imagine the ensuing entertainment stemming from a failure to seat!

 

[R4_GRN]

thanks for all the replies, I must remember never to stand in front of a sight glass

 

[jamieP]

thanks for all the replies, I must remember never to stand in front of a sight glass

I really wouldn't worry. Iv been working in steam for 10 years any never had ine blow.