Trafag Gas Density Controllers 1

[supraskate13]

My company has just recently tested a bunch of Trafag gas density monitors. At a nominal 20 degrees C (68 F) The set point (closes a b finger contact) is at 50 psig and the reset point (opens the contact back up) is at 57 psig. leaving a dead band of 7 psig from set to reset pressures. The problem I'm having is that when we tested these the air temp was in the high 80's F. And just for an example the measured set point was at 46 psig and the reset point was at 48 psig. so now the dead band from set to reset is only 2psig. Is this normal? it just seems to me that eventually the set and reset points are going to over lap each other with increasing temperature.

 

[Barry1961]

That does not sound normal to me. If possible I would re-check the sensor from low to high temp. then call Tarfag.

I can't think of any part of the mechanical assembly that would be affected that much by that small of a change in temp.

The only thing I can think of is that it may have been sticking the first few times it actuated giving a high differential.

Barry1961