Portable fan booster for air vents

Claim 1

In combination: a register having a register opening for delivering heated or cooled air into a room; a housing having a closed top wall, a bottom wall spaced below said top wall, and a side wall interconnecting said top wall and said bottom wall and enclosing a fan chamber therebetween; said bottom wall having at least one air intake opening therein positioned over said register opening for permitting air flow from said register into said fan chamber; said side wall having at least one air outlet opening permitting air flow from said fan chamber to the exterior of said housing; a centrifugal fan rotor rotatably mounted in said fan chamber for rotation about a fan axis extending in a line which intersects said bottom wall and said top wall, said fan rotor having radially extending blades shaped to force air radially outwardly from said fan axis toward said air outlet in response to rotation of said fan rotor about said fan axis; a motor located completely within said fan chamber and connected to said fan rotor for rotating said fan rotor about said fan axis; an air filter positioned in covering relation over at least one of said air intake opening or said air outlet opening for filtering dust form air passing from said register through said fan chamber; a power circuit connected to said motor; a switch between said power circuit and said motor, said switch being in an open circuit condition in response to a first signal and being responsive to a second signal to change to a closed circuit condition; a temperature sensing circuit operatively connected to said switch, said temperature sensing circuit including a thermistor positioned to be exposed to air temperature within said fan chamber; said temperature sensing circuit being capable of sending one of said first and second signals to said switch in response to said thermistor being exposed to an air temperature above a preselected temperature and being capable of sending the other of said first and second signals to said switch when said thermistor is exposed to an air temperature below said preselected temperature; a fan control support supporting said power circuit, said switch, and said temperature sensing circuit within said fan chamber.