Boiler gauge glass needs to be blow down, regularly, to make sure that it is showing the correct reading and there is no blockage in the line of water and steam. This is also to check that, water and steam cocks are not leaking. This is a physical mean of showing the correct level of water in the boiler.
Here are the steps that you will follow, when blowing down the boiler gauge glass:
1) Make sure that you have worn the protective gear like goggles and gloves.
2) Shut the steam, and water cock for the gauge glass,
3) Drain it by opening it slowly. If the water is still coming, that means, water cock is leaking and same goes with the steam also, if it happens.
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4) Now slowly open the water cock and let it remain like this for 5 seconds.
5) Now close the water cock and open the steam cock (Be careful)
6) After it close the steam cock, followed by the drain cock.
7) Now open the water cock and let it remain open.
8) It’s time to open the steam cock.
9) After 10 seconds, you will see the correct level in the gauge glass.
10) You are done with the gauge glass blow done J
So this was the whole process that needs to be carried out.
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Ans: Well the right approach for it is that, you tighten the inner bolts and then starting tightening the bolts in successive cross manner as you go outside. After that, it is time to tight them from outside to inside.
Below you can see the correct pattern of tightening the Bolts
The reason why we are doing it is that; consider a situation when you start applying force on a plate from both the ends, what will happen? It will buckle up-Right? So the right approach is to, tight it from inside to outside, so that if there is any expansion on it, it will be relieved outside.