Patent ID: 7617989

Claim:
A thermostatic control device for a flow control valve having a valve body and an axially movable plug member provided with a stem, the device comprising: a base body secured to the body of the valve; an axially extensible thermostatic actuator having a heating element; intermediate connecting means between the thermostatic actuator and the stem of the valve plug; counteracting spring means conformed and disposed between the base body of the device and the intermediate connecting means; a cap assembly for housing the thermostatic actuator and the intermediate connecting means, said cap assembly comprising a cylindrical portion secured to said base body, and a control knob movably supported by said cylindrical portion of the cap assembly, the control knob being in turn operatively connected to the stem of the valve plug by said intermediate connecting means; cam means conformed and arranged to cause an axial movement of the control knob by the manual rotation of the control knob between a first position and a second position; retaining means for retaining the control knob in said second position, said retaining means being conformed and operatively connected to the thermostatic actuator to cause disengagement of the retaining means from the control knob upon extension of the thermostatic actuator caused by said heating element, and torsional spring means arranged for automatically moving the control knob from said second position to said first position upon disengagement of the control knob from said retaining means.