Dear Sirs,

I've just bought a new Steam Sterilizer 21 Litres single wall and it use Pressure Switch instead of Temp Controller. My friends told me it can not use because it not has a Steam Trap so temperature can not reach really temp sterilizing. What do you think? Should I change it?

Wisit Chai

Wisit we are talking here about a benchtop sterilizer. Most sterilisers of this class utilise a temperature controller situated on the lowest point (displacement point) but it is quite common that their is no steam trap in situ.
The method used to remove air which acts as an insulator against moist steam is an air vent, these devices can be crude and are not thermostatic and close of when it spring torque is overcome.
The problem with a pressure switch is that steam at 2.2bg is 134c but if 1.6 bg was steam and .6bg was air the saturated temp is 128.7 c.
Wisit I would advice you to confirm the temperature temp/time duration on the product your processing, thermostatically (thermocouples attached/submerged on product) for the required specification. eg: 3 minutes @ 134. Use this info as part of your quality control for MPR.

YOURS