UNIQUE PHOTO OF THE MONTH

Mechanical Seal:

I am asked to monitor a wide variety of components at the paper mills, power plants and other industries I scan regularly. 

The image above is a typical pump, showing a close-up of the shaft an mechanical seal.  The seal prevents the fluid from spilling out of the pump along the shaft.  It is held mechanically - with the aid of bolts - sandwiching a packing material inside the seal.

This packing needs to be held firmly in place, but, too tight and the friction will generate heat.  Seals are also cooled with seal water (simply, cold water that flows in one side of the seal and out the other (as pictured), or sometimes, it flows through the seal and into the pump.

Pictured above, we show a thermal photo of what a pump seal looks like if either of the two scenarios described above happen.  The heat is greatest at the shaft.  When you find a hot seal, also take a look at the seal water inlet and outlet lines... is the temperature of the seal water line cool coming in and warmer coming out?  This would indicate the seal water is flowing - therefore you likely have a mechanical seal that is too tight.  The photo above shows warm temps on the seal water outlet, but it stops at the valve.  There is no handle on the valve, but the gauge indicates there is pressure at the gauge... so, the valve is likely closed after the gauge.

If your company is not scanning with the proper equipment... you may be missing the details!  Preventing failures requires consistent monitoring, proper access and a thermographer that knows what he is doing.  Having the right equipment for the job helps too!