It is a dual function valve: level control and liquid injection. It is used in flooded evaporators, intermediate coolers and liquid separators.
Formed by a thermostatic valve whose sensor is a bulb charged with a saturated liquid immersed in a heating resistor. The sensor is positioned exactly where it is desired to keep the level constant and is mounted in such a way that it contacts the refrigerant fluid whenever it rises. Upon contact with the refrigerant, the pressure within the bulb tends to fall causing the valve to close and thereby reduce the flow of liquid into the separator.
