USUALLY BOILER DRUM LEVEL GLASS ISOLATION VALVES ARE BALL VALVE AND THEY ARE OPPOSITE IN DIRECTION. MEAN NORMALLY IF HANDLE OF VALVE IS PARALLEL TO THE LINE ITS MEAN IT IS OPEN, BUT IN BOILER DRUM LEVEL GLASS IN THIS CONDITION IT WILL BE CLOSE. SO PLEASE ANYBODY EXPLAIN ME WHAT THE PURPOSE BEHIND THIS FASHION?

 

This is because when the boiler drum may vibrates during in operation. the handle might moves down and valve will shut. Then the water level shown in the sight glass might not represent the actual water level in the boiler drum. That's why the boiler sight glass isolation valve handle position (OPEN/CLOSE) is design opposite way than the normal way.

 

THANKS DEAR

BUT ONE MORE CONFUSION IS, WHY LEVEL GAUGE GLASS DRAIN VALVE IS ALSO OPPOSITE, CAN YOU PLEASE EXPLAIN WHY?