Return gizmo in large steam system

Steamhead (in transit)

if the unit heaters would run on the lower pressure, if their returns were piped down to the floor level rather than up? If there's no other reason for the higher pressure (process work etc) this might be an attractive option. Lower pressure = lower fuel consumption.

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ttekushan_2

Identify return Gizmo in large steam system

Helllo everyone.

I'm troubleshooting a 150 HP steam heating system in a 110,000 square foot factory. Its an overhead system, complete with high mounted pipe coils, unit heaters, and standing cast iron wall radiators along all the walls,

5% of problems are ravages of age and 95% are ravages of maintenance personnel.

So anyway, can anyone descibe what these gizmos do? My instinct tells me that they are sort of an intermediate return flash chamber to prevent hammer in the dry returns. They are supplied with the condensate and air from the end of the major mains through an F&T trap. Now, there's also and F&T at the discharge of this thing. BUT there's what appears to be a tall vent line coming out of the top. They are capped. Was there a vent here? Or was this connected to some other vent source or heat producing source.. Too much is missing for me to know for sure. One is still in service. The other is bypassed entirely. BTW, the end of main hammers like crazy at start-up, where the gizmo is bypassed. But that may only be a drainage and insulation issue. On the other hand the other end of main (where this thing is still in use) is no better off and is silent.

Feel free to educate my butt!

-Terry

Steamhead (in transit)

Have you been able to determine

whether part of this system ran at higher pressures than the usual 2 PSI? That would be the reason for flash chambers.

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ttekushan_2

Yes.

Thanks for the quick reply!

Yea. There are unit heaters piped in the "higher" pressure way, with the the bottom coils below the return line level. Its only about 6" but this isn't low pressure stuff. The riser from the boiler room to the roof is a 4" line, feeding the unit heaters and the two LARGER diameter mains for the standing radiation. These lower pressure mains are where these devices are.

Since there are no pressure reducing valves employed, the transition to larger mains is simple and effective UNTIL saturation is reached. If every trap in the place closes, everything will see something close to that riser pressure.

Ten lbs at the boiler divides twice giving about 2 to 2.5 pounds at the radiators. Radiator heating time and surface temperature (using a raytek infrared thermometer) are consistent with this. But saturation does up the ante. Not to 10 lbs, but closer to 5. Of course, every time I'm in there, its 45 degrees in there and with all that 1920 era concrete, saturation is a bit theoretical!

As an aside, its a real thrill to observe a system of this magnitude in action. The place is currently unoccupied, so I've got it all to myself while working. The whole place starts to breath, and you can hear the rushing of the steam flying through the riser and first areas of distribution. Wow.

And the boiler is one of those interesting Sellers forced induction boilers, where each fire tube has its own burner.

Awesome.