Abstract: An expansion valve (10) for controlling the flow rate of refrigerant supplied to an evaporator (1) of a refrigerating system comprises a temperature-sensing chamber (30) entirely provided within the housing (11) of said expansion valve in a low pressure passage (12) thereof. Said passage (13) is connected to the outlet of said evaporator (1) and the inlet of a compressor (2), for converting a temperature change into a pressure change in order to actuate a valve mechanism (20) in response to a rise and lowering in pressure of said temperature-sensing chamber to open and close a passage (13) for adiabatic expansion of the refrigerant. Said temperature-sensing chamber (30) contains a sealed gas charge and an adsorbent material (35) for adsorbing and releasing said gaseous medium in accordance with temperature changes sensed.