Burner units for gas appliances

Claim 2

A burner unit for a gas appliance comprising: A. an enclosure, B. a gas burner within the enclosure, C. a gas inlet pipe extending through a wall of the enclosure to the burner, D. ignition means located within the enclosure and i. operable from outside the enclosure to ignite the burner when gas is supplied thereto, E. an air intake for admitting air into the enclosure F. fine mesh means extending across the air intake and serving as a barrier which prevents the passage of a flame therethrough, G. a flue extending upwardly in a gas tight manner from an opening in the top of the enclosure for carrying away burnt gases from the enclosure and H. fine mesh means extending across the flue and serving as a barrier which prevents the passage of a flame therethrough.

Claim 3

A burner unit according to claim 1 incorporating a gas cut-off device for the burner and operative to cut off the supply of gas thereto when the burner flame is extinguished.

Claim 4

A burner unit according to claim 2 including an electrical control circuit having a starting switch which, upon closure, causes opening of a gas valve to supply gas to the burner, and also operation of the ignition means, the circuit incorporating also a temperature-controlled switch which is operable in response to heat from the burner flame to maintain the gas valve in the open condition despIte subsequent opening of the starting switch, but which allows the gas valve to close when the burner flame is extinguished.

Claim 5

A burner unit according to claim 3 wherein the temperature-controlled switch is a bimetallic switch or a thermistor.

Claim 6

A burner unit according to claim 3 incorporating a relay energisable on closure of said starting switch, and in which closure of the temperature-controlled switch is effective to maintain the relay in the energised condition, the gas valve being openable on energisation of the relay.

Claim 7

A burner unit as claimed in claim 5 incorporating a transistor in series with said relay, and in which closure of the temperature-controlled switch is effective to maintain the transistor conductive and thereby to maintain the relay in the energised condition.

Claim 8

A burner unit as claimed in claim 5 including a relay switch in the base line of the transistor which is openable to render the transistor non-conductive when the relay is energised unless the temperature-controlled switch is closed, and a capacitor in the base collector circuit of the transistor for maintaining the base bias of the transistor for a predetermined length of time following the opening of the relay switch.

Claim 9

A burner unit according to claim 2 including a thermally responsive actuating device operable on a gas valve supplying gas to the burner to maintain it in the open condition when the burner is alight, but which causes or permits the valve to close when the burner flame is extinguished, and means for permitting gas to be supplied to the burner during operation of the ignition means to ignite the burner, and for a period sufficient to enable the thermally responsive actuating device to open the gas valve.

Claim 10

A burner unit according to claim 1 in which there is an additional fine wire mesh extending across the air intake and spaced from the first mesh.

Claim 11

A burner unit according to claim 9 wherein the additional mesh is spaced from the first mesh a distance of the order of one-eighth to one-fourth inch.

Claim 12

A burner unit for a gas appliance comprising: A. an enclosure, B. a gas burner within the enclosure, C. a gas inlet pipe extending through a wall of the enclosure to the burner, D. ignition means located within the enclosure and i. operable from outside the enclosure to ignite the burner when gas is supplied thereto, E. a flue pipe for carrying away burnt gases from the enclosure, F. an air intake for admitting air into the enclosure, and G. a fine mesh of sufficiently small aperture size to prevent the passage of a flame therethrough extending across the air intake, H. the enclosure comprising a main part and a removable panel attachable in a gas-tight manner to the main part, I. the ignition means being in the form of a spark gap adjacent the burner and a voltage generator operable to generate a voltage sufficient to produce a spark across the spark gap, and the spark gap comprising a pair of electrodes, one of which is carried by the main part of the enclosure and the other of which is carried by the removable panel.

Claim 13

A burner unit for a gas appliance comprising: A. an enclosure, B. a gas burner within the enclosure, C. a gas inlet pipe extending through a wall of the enclosure to the burner, D. ignition means located within the enclosure and i. operable from outside the enclosure to ignite the burner when gas is supplied thereto, E. a flue pipe for carrying away burnt gases from the enclosure, F. an air intake for admitting air into the enclosure, and G. a fine mesh of sufficiently small aperture size to prevent the passage of a flame therethrough extending across the air intake, H. the enclosure comprising a main part and a removable panel attachable in a gas-tight manner to the main part, I. the ignition means being in the form of a spark gap adjacent the burner and a voltage generator operable to generate a voltage sufficient to produce a spark across the spark gap, and the spark gap comprising a pair of electrodes, one of which is carried by the main part of the enclosure and the other of which is carried by the removable panel.

Claim 14

A burner unit according to claim 11 incorporating or associated with a warning or indicating device operative to show when the burner is extinguished.

Claim 15

A burner unit according to claim 11 wherein the burner itself provides one of the spark gap electrodes.

Claim 16

A burner unit according to claim 11 having an additional fine mesh extending across the air intake, and spaced from the first mesh a distance of the order of one-eighth to one-fourth inch.

Claim 17

A burner unit according to claim 11 including a pair of spaced wire meshes of an aperture size sufficiently small to prevent the passage of a flame therethrough extending across the flue.

Claim 18

A burner unit according to claim 15 wherein the meshes which extend across the flue are spaced apart a distance of the order of one-eighth to one-fourth inch.

Claim 19

A burner unit for a gas appliance coMprising: A. an enclosure, B. a gas burner within the enclosure. C. a gas inlet pipe extending through a wall of the enclosure to the burner, D. ignition means located within the enclosure and i. operable from outside the enclosure to ignite the burner when gas is supplied thereto, E. an air intake for admitting air into the enclosure, F. a pair of fine mesh means each extending across the air intake and spaced from one another to serve as barriers to the passage of a flame therethrough G. a flue extending upwards in a gas tight manner from an opening in the top of the enclosure for carrying away burnt gases from the enclosure and H. a further fine mesh means extending across the flue to serve as a barrier to the passage of a flame therethrough.

Claim 20

A burner unit for a gas appliance coMprising: A. an enclosure, B. a gas burner within the enclosure. C. a gas inlet pipe extending through a wall of the enclosure to the burner, D. ignition means located within the enclosure and i. operable from outside the enclosure to ignite the burner when gas is supplied thereto, E. an air intake for admitting air into the enclosure, F. a pair of fine mesh means each extending across the air intake and spaced from one another to serve as barriers to the passage of a flame therethrough G. a flue extending upwards in a gas tight manner from an opening in the top of the enclosure for carrying away burnt gases from the enclosure and H. a further fine mesh means extending across the flue to serve as a barrier to the passage of a flame therethrough.