Variable orifice gas flow modulating valve

A gas appliance comprising:

• a burner;
• an orifice hood including a wall defining a recess and an outlet orifice, the recess including a tapered section that narrows from a wide portion to a narrow portion, the outlet orifice extending from the narrow portion of the recess through the wall to an outer surface of the orifice hood and feeding directly into the burner;
• a metering pin including
• a central portion extending along a longitudinal axis of the metering pin, and
• a plurality of fins each extending radially outwardly from the central portion, the fins and central portion being tapered at an end of the metering pin such that the tapered portion of the metering pin conforms to the tapered section of the recess, the metering pin including a passage for allowing gas to pass through the metering pin to the outlet orifice;
• an actuator for moving the pin between an open position where the metering pin is separated from the tapered section of the recess by a distance and allows gas to flow around an outer surface of the tapered portion of the pin to the outlet orifice, and a closed position where the tapered portion of the metering pin is seated against the tapered section of the recess and restricts substantially all gas flow to the passage of the metering pin and the outlet orifice;
• and
• a control system for measuring an internal temperature of the appliance and driving the actuator in response to the internal temperature.

A method of modulating gas flow in a gas appliance, the method comprising:

• sensing a temperature;
• moving a metering pin toward a closed position in a recess of an orifice hood if the temperature is higher than a selected temperature but stopping the metering pin short of the closed position, the orifice hood including an outlet orifice opening directly into a burner of the gas appliance, the gas flow being constrained to a first passageway through the metering pin and the outlet orifice when the metering pin is in the closed position;
• and
• moving the metering pin toward an open position in the recess if the temperature is lower than the selected temperature but stopping the metering pin short of the open position, the gas flow following the first passageway and at least one additional passageway along the metering pin to the outlet orifice when the metering pin is in the open position.

A method of modulating gas flow in a gas appliance, the method comprising:

• sensing a temperature;
• moving an orifice hood toward a closed position relative to a metering pin if the temperature is higher than a selected temperature but stopping the orifice hood short of the closed position, the orifice hood including an outlet orifice opening directly into a burner of the gas appliance, the gas flow being constrained to a first passageway through the metering pin and the outlet orifice when the orifice hood is in the closed position;
• and
• moving the orifice hood toward an open position relative to the metering pin if the temperature is lower than the selected temperature but stopping the orifice hood short of the open position, the gas flow following the first passageway and at least one additional passageway along the metering pin to the outlet orifice when the orifice hood is in the open position.

A variable orifice gas flow modulating valve comprising:

• an orifice hood with a wall defining a recess and an outlet orifice, the recess including a tapered section that narrows from a wide portion to a narrow portion, the outlet orifice extending from the narrow portion of the recess through the wall to an outer surface of the orifice hood, the recess further including attachment threads;
• a fixed outlet port with outer threads engaging the attachment threads of the orifice hood;
• a metering pin including
• a central portion extending along a length of the metering pin, and
• a plurality of fins each extending radially outwardly from the central portion, the fins and central portion being tapered at an end of the metering pin such that the tapered portion of the metering pin conforms to the tapered section of the recess, the metering pin including a passage for allowing gas to pass through the metering pin to the outlet orifice;
• an actuator for rotating the orifice hood so that it moves between an open position where the metering pin is separated from the tapered section of the recess by a distance and gas flows around an outer surface of the tapered portion of the pin to the outlet orifice, and a closed position where the tapered portion of the metering pin is seated against the tapered section of the recess and substantially all gas flow is through the passage of the metering pin and the outlet orifice.

A variable orifice gas flow modulating valve comprising:

• an orifice hood with a wall defining a recess and an outlet orifice, the recess including a tapered section that narrows from a wide portion to a narrow portion, the outlet orifice extending from the narrow portion of the recess through the wall to an outer surface of the orifice hood;
• a metering pin including
• a central portion extending along a length of the metering pin, and
• a plurality of fins each extending radially outwardly from the central portion, the fins and central portion being tapered at an end of the metering pin such that the tapered portion of the metering pin conforms to the tapered section of the recess, the metering pin including a passage for allowing gas to pass through the metering pin to the outlet orifice;
• an actuator for causing the orifice hood to move between an open position where the metering pin is separated from the tapered section of the recess by a distance and gas flows around an outer surface of the tapered portion of the pin to the outlet orifice, and a closed position where the tapered portion of the metering pin is seated against the tapered section of the recess and substantially all gas flow is through the passage of the metering pin and the outlet orifice.