US 5,567,143 A · Flue draft malfunction detector and shut-off control for oil burner furnaces

Abstract

Flue-draft-malfunction detector and shut-off control for oil burner furnaces automatically stops operation of the oil burner in event of flue draft malfunction and prevents further running operation of the oil burner until a meltable element in the control is replaced by an intact element. The control casing has a passageway with an inlet on its front end and at least one outlet. The control is mountable on a furnace with the inlet communicating with the furnace combustion chamber. The meltable element is removably positioned within the casing for exposure to the passageway. Two electrical conductors extend from opposite ends of the element and serve as leads connectable in circuit across two terminals of a primary oil burner control so the element completes a circuit between these terminals. Flue draft malfunction causes positive pressure in the combustion chamber during running of the burner, thereby forcing hot combustion gasses to flow from the combustion chamber through the passageway and out into ambient air. The element does not melt from a start-up puff but will melt from persisting flow of hot gases flowing through the passageway exceeding a predetermined temperature level, thereby interrupting the circuit for immediately stopping the burner. Since the melted open-circuit element advantageously prevents restarting continuing normal running operation of a burner in a furnace having a malfunctioning flue draft, a mechanic will be called who will fix the flue draft and replace the melted element for enabling restarting normal burner operation.

Claims20

Dependent claims

A flue-draft-malfunction detector and shut-off control for an oil burner furnace for automatically stopping operation of the oil burner in event of draft malfunction, said control comprising:

mounting means having a passageway therein with an inlet into said passageway and at least one outlet from said passageway,
said mounting means being mountable on a furnace with said inlet being in communication with a combustion chamber within the furnace and with the outlet being in communication with ambient air near the furnace,
a meltable, electrically-conductive element having first and second terminals,
first and second electrical conductors connected to said first and second terminals,
positioning means for said element for holding said element exposed to said passageway,
said element being meltable at a temperature in said passageway exceeding a predetermined level due to positive pressure within the combustion chamber causing hot combustion gases to blow from the combustion chamber into said inlet and through said passageway and out from said outlet, and
said first and second electrical leads being connectable in a circuit between terminals of a control device of an oil burner for including said element in said circuit to complete said circuit between said terminals of the control device for enabling operation of the oil burner and for preventing operation of the oil burner upon interruption of said circuit by melting of said element.

4 more elements

A flue-draft-malfunction detector and shut-off control for an oil burner furnace for automatically stopping operation of the oil burner in event of flue draft malfunction, said control comprising:

a heat-resistant casing having forward and rearward ends,
said heat resistant casing having a passageway therein with an inlet into said passageway and at least one outlet from said passageway,
said inlet being in said forward end of said casing,
mounting means for mounting said casing on a furnace with said inlet being in communication with a combustion chamber within the furnace and with the outlet being in communication with ambient air near the furnace,
a meltable, electrically-conductive element having first and second terminals,
first and second electrical conductors connected to said first and second terminals,
positioning means for said element for holding said element within said casing exposed to said passageway,
said element being meltable at a temperature in said passageway exceeding a predetermined level due to positive pressure within the combustion chamber causing hot combustion gases to flow from the combustion chamber into said inlet and through said passageway and out from said outlet, and
said first and second electrical conductors extending from said casing.

6 more elements

Dependencies are inferred from the claim text.

Flue draft malfunction detector and shut-off control for oil burner furnaces

Life of this patent

Flue draft malfunction detector and shut-off control for oil burner furnaces

Life of this patent

Abstract

Claims20