Thermoelectric sensor
AssigneeBritish Gas Corporation
InventorDavid M. Sutton
Life of this patent
Estimating the term…
Abstract
A thermoelectric sensor assembly 1 for use with a flamestrip 9 in a fuel gas burner. The sensor assembly may be in the form of a probe 2 having temperature sensors 5a,b,c,d downstream of the flamestrip 9 in and adjacent the flame region, and temperature sensors 6a,b,c upstream of the flamestrip. A voltage output signal from the sensor assembly is used as an indication of the aeration of the flame and/or of flame establishment and/or flame failure and/or flame lightback.
Claims26
A thermoelectric sensing device for use in a fully premixed air/fuel gas burner apparatus comprising a flamestrip through which premixed air and fuel gas can pass for combustion in the vicinity of a downstream side of the flamestrip relative to the intended direction of flow of the premixture through the strip, the device comprising:
- an elongate supporting body;
- a plurality of temperature sensors on said supporting body and comprising discrete thermojunctions which define "hot" junctions and which are electrically connected alternately in series with at least one further discrete thermojunction, the at least one further discrete thermojunction serving as a "cold" junction, wherein when the device is located in said gas burner apparatus and in position with respect to the flamestrip, the "hot" junctions are at different predetermined distances downstream of an upstream side of the flamestrip, the individual "hot" junctions being so dimensioned and spaced from each other as to generate an aggregate output voltage which changes in a generally step-like manner as the flamefront of a flame supported by the flamestrip moves over the region occupied by the plurality of the "hot" junctions and successively across the "hot" junctions, with relatively large changes in the voltage output occurring as the flamefront crosses each "hot" junction and with the voltage output remaining at a relatively constant value as the flamefront moves across the region, between successive "hot" junctions, and wherein each of the at least one "cold" junctions is spaced from all of the "hot" junctions in the longitudinal direction of the elongate body and upstream of the flamestrip;
- and
- conducting means via which voltage output signals emanating from the junctions can be sensed.
A device as claimed in any of the preceding claims, in which the at least one "cold" junction can sense increased temperature upstream of the flamestrip, as a result of flame lightback occurring through the flamestrip and in response thereto to generate a voltage output which can be sensed via said conducting means.
A fully premixed air/fuel gas burner apparatus comprising:
- a flamestrip through which premixed air and fuel gas can pass for combustion in the vicinity of a downstream side of the flamestrip relative to the intended direction of flow of the premixture through the strip;
- a thermoelectric sensing device located in position with respect to the flamestrip, the device comprising an elongate supporting body;
- a plurality of temperature sensors on said supporting body and comprising discrete thermojunctions which define "hot" junctions and which are electrically connected alternately in series with at least one further discrete thermojunction, the at least one discrete further thermojunction serving as a "cold" junction, wherein the "hot" junctions are at different predetermined distances downstream of an upstream side of the flamestrip, the individual "hot" junctions being so dimensioned and spaced from each other as to generate an aggregate voltage output which changes in a generally step-like manner as the flamefront of a flame supported by the flamestrip moves over the region occupied by the plurality of the "hot" junctions and successively across the "hot" junctions, with relatively large changes in the voltage output occurring as the flamefront crosses each "hot" junction and with the voltage output remaining at a relatively constant value as the flamefront moves across the region between successive "hot" junctions, and wherein each of the at least one "cold" junctions is at a position spaced from all of the "hot" junctions in the longitudinal direction of the elongate body and upstream of the flamestrip;
- conducting means via which voltage output signals emanating from the junctions can be sensed;
- and
- signal processing means responsive to the voltage output signals for controlling the burner apparatus.
A combination of a thermoelectric sensing device and a flamestrip for use in a fully premixed air/fuel gas burner apparatus, through which flamestrip, when in use, premixed air and fuel gas can pass for combustion in the vicinity of a downstream side of the flamestrip;
- and wherein the device is fixed or secured to the flamestrip and comprises:
- an elongate supporting body;
- a plurality of temperature sensors comprising discrete thermojunctions defining "hot" junctions electrically connected alternately in series with at least one further discrete thermojunction, the at least one further discrete thermojunction defining a "cold" junction, wherein the "hot" junctions are at different predetermined distances downstream of an upstream side of the flamestrip, the individual "hot" junctions being so dimensioned and spaced from each other as to generate an aggregate voltage output which changes in a generally steplike manner as the flamefront of a flame supported by the flamestrip moves over the region occupied by the plurality of the "hot" junctions and successively across the "hot" junctions, with relatively large changes in the voltage output occurring as the flamefront crosses each "hot" junction and with the voltage output remaining at a relatively constant value as the flamefront moves across the region between successive "hot" junctions, and wherein the at least one "cold" junction is at a position spaced from all of the "hot" junctions in the longitudinal direction of the elongate body and upstream of the flamestrip;
- and
- conducting means via which voltage output signals emanating from the junctions can be sensed.
Dependencies are inferred from the claim text.