Liquid Expansion Thermostatic Valve

Liquid Expansion Thermostatic Valve
Principle
Liquid when heated expands.
Liquid Expansion Thermostatic Valve
Construction
Liquid is contained in a copper PHIAL
Connected to flexible metal BELLOWS
by a CAPILLARY TUBE
Liquid Expansion Thermostatic Valve
Operation
The gas valve is attached to the BELLOWS.
When temp increases the bellows expand pushing the valve onto its seat.
This stops the gas flow to the burner via that route
Liquid Expansion Thermostatic Valve
Operation of By pass screw
BY pass screw allows a small flow rate to the burner.
so when temp is reached it is not extinguished.
By pass rate is designed to maintain desired temp.
Liquid Expansion Thermostatic Valve
Disc on seat valve
Disc is assisted onto its seat by a spring.
If temp falls liquid contracts
Bellows contract pulling valve away from seat.
This restores main gas rate to burner
Liquid Expansion Thermostatic Valve
Temperature Adjustment
achieved by temp adjustment bar when turned will move valve closer or further from its seat.
Results in a lower or higher temp before by pass rate is acheived
Liquid Expansion Thermostatic Valve
Appliances
Most commonly found on
GAS COOKER OVENS