Rectangular Sight glass on a cylinder

[Chandanraj123]

Hi,

I am designing a pressure vessel, this vessel has got a rectangular sight glass on its shell, this vessel is designed and built to AS1210-2010. The code says the major axis "should" be in the circumferential direction. I am not really sure whether we can have a rectangular fitting's major axis in any direction if this passes the reinforcement calcs as per the code.



Any suggestions would be highly appreciated.......

Thank you & Regards,

Chandanraj
Design Engineer

 

[austsa]

What is vessel's orientation? What is purpose of rectangular sight glass? to determine liquid level inside the vessel?

If vessel is vertical and sight glass is for liquid level, then the major axis of the fitting will have to be longitudinal. If vessel is horizontal, then circumferential direction. Welding a long fitting longitudinally along a vessel is generally not preferred (as it is perpendicular to hoop stress direction).

 

[Chandanraj123]

HI austsa,

Thanks for your reply above.....please see my comments below....

The vessel is a vertical vessel. And yes the sight glass is to check the liquid level.

This is a very small vessel, please see the dimensions of the vessel and sight glass below,

vessel shell is made of 600NB sch40s pipe 750mm long and has got a custom machined flange at the top and tori head to suit the pipe bottom.

sight glass dimension is 300 x 70, but the opening / viewing dimensions are 280 x 18 mm.

The required thickness (2.5mm for vacuum pressure of 100 kPag) is considerably less than the thickness used on the shell (600NB SCH40s = 9.53mm thick).

I have done the reinforcement calculations as required, it passes easily.

Any suggestions would be highly appreciated....

Thank you &

Regards,
Chandanraj Basavaraju

 

[austsa]

If your gauge involves long continuous longitudinal welds onto vessel wall, then blend the welds and conduct NDT. Alternatively, there are gauges that bolt onto 2 flanges on the vessel. As you have indicated, code says 'should' (not 'shall'). Check with your client also.