Abstract: Methods and systems for providing an image with an answer to a question query. A method receiving a first query that is determined to be a question query; generating a second query form the first query; causing a search of a plurality of resources of a first corpus using the second query as input, wherein the first corpus of resources are resources that include images and textual data rendered with the images; receiving data indicating a set of resources determined to be responsive to the second query; causing a search for images in the set of resources; selecting, from the set of images and based in part on the search for images in the first set of resources, an image to be provided with the answer in response to the query; and providing, by the data processing apparatus, and with the answer, the image in response to the first query.

Abstract: Methods and systems for providing an image with an answer to a question query. A method receiving a first query that is determined to be a question query; generating a second query form the first query; causing a search of a plurality of resources of a first corpus using the second query as input, wherein the first corpus of resources are resources that include images and textual data rendered with the images; receiving data indicating a set of resources determined to be responsive to the second query; causing a search for images in the set of resources; selecting, from the set of images and based in part on the search for images in the first set of resources, an image to be provided with the answer in response to the query; and providing, by the data processing apparatus, and with the answer, the image in response to the first query.

Abstract: The present concept is a radiant tube assembly that includes a burner assembly firing combustion gases into a combustion tube which emits radiant heat energy from its outer surface. A black ceramic coating is applied the outer surface of the combustion tube to increase the emissivity of the combustion tube and lower the temperature of the outer surface of the combustion tube. Semi-circular top and semi-circular bottom inserts extending longitudinally along the length of a first section of the combustion tube lower the combustion tube outer temperature.

Abstract: A reflector for an elongate radiant tube heater having a tubular conduit through which hot combustion gases flow comprises an elongate metal reflecting member that can extend along the length of the tube heater in order to cover the top and sides thereof and a layer of heat resistant insulation extending over the reflecting member. The reflector includes two central panel portions meeting along the longitudinal centerline and forming an outwardly facing angle ranging between 30 and 100 degrees, preferably between 45 and 80 degrees. A bisector of this angle extends substantially vertically and is vertically aligned with a centerline of the tubular conduit during use of the reflector. The reflector has several longitudinal panel sections extending outwardly and downwardly from the central panel portions.

Abstract: A pitot tube assembly is provided for a radiant tube heater having a blower for providing combustion air to a burner. The assembly includes a mounting plate for attaching the assembly to a wall of a housing of the blower. First and second, substantially L-shaped pitot tubes extend through the mounting plate and are connected thereto and have respective inner leg sections which are arranged within an outlet section of the blower during use of the radiant tube heater. These leg sections extend in opposite directions to their respective pressure sensing ends. The first pitot tube measures impact pressure created by the blower and the second pitot tube measures static pressure. These tubes are connectible to a differential pressure switch arrangement for controlling operation of the burner. As part of a burner assembly, there is a mixing cup unit mountable within the burner tube of the heater and capable of mixing primary air and combustible gas. A gas valve unit regulates flow of the gas to the cup assembly.

Abstract: A method of measuring heat flux received on a selected area from a radiant tube heater includes providing an enclosing wall along side edges of the selected area and the radiant tube heater having a radiant heating tube mounted above the area. A heat flux sensor whose operating temperature can be regulated is used and is placed on a grid formed on the selected area, this grid defining a plurality of side-by-side sensor locations, each corresponding respectively to an area covered by one heat flux sensor. The heat flux received at each sensor location is measured and the sensor is moved sequentially from one sensor location to an adjacent sensor location after each measurement.

Abstract: A reflector for an elongate radiant tube heater having a tubular conduit through which hot combustion gases flow comprises an elongate metal reflecting member that can extend along the length of the tube heater in order to cover the top and sides thereof and a layer of heat resistant insulation extending over the reflecting member. The reflector includes two central panel portions meeting along the longitudinal centerline and forming an outwardly facing angle ranging between 30 and 100 degrees, preferably between 45 and 80 degrees. A bisector of this angle extends substantially vertically and is vertically aligned with a centerline of the tubular conduit during use of the reflector. The reflector has several longitudinal panel sections extending outwardly and downwardly from the central panel portions.

Abstract: A method of measuring heat flux received on a selected area from a radiant tube heater includes providing an enclosing wall along side edges of the selected area and the radiant tube heater having a radiant heating tube mounted above the area. A heat flux sensor whose operating temperature can be regulated is used and is placed on a grid formed on the selected area, this grid defining a plurality of side-by-side sensor locations, each corresponding respectively to an area covered by one heat flux sensor. The heat flux received at each sensor location is measured and the sensor is moved sequentially from one sensor location to an adjacent sensor location after each measurement.

Abstract: A radiant tube heater has a tubular arrangement with an air duct portion forming a combustion air passage and a radiant tube portion which is heated by and surrounds a laminar flame. An inlet end of the air duct portion receives combustion air from a blower. A burner assembly mounted in the air duct portion includes a burner nozzle and a burner head for mixing gas and combustion air, this head having an inlet portion and an outlet portion wider than the inlet portion. A perforated restricting plate is mounted in the air duct portion and extends around the burner head. Air holes in this plate are sized and distributed so that the plate increases flow of combustion air through openings formed in the side of the inlet portion and allows combustion air to flow in the annular passage between the outlet portion and the air duct portion.

Abstract: A burner assembly for a radiant tube heater having an air duct portion for passage of combustion air to a radiant tube portion includes a mixing cup for mixing combustible gas and air and delivering the mixture to the tube. This cup has an inlet portion and a larger cylindrical outlet portion. Air inlet holes are formed in an upstream end wall of the outlet portion and air ports are formed in a peripheral wall of the inlet portion. An air diverter mounted at an upstream end of the inlet portion has a set of blade which divert a portion of the air through the ports for initial mixing with the gas while a second portion of the air flows through the inlet holes providing additional primary air for mixing. An airflow restricting plate can be mounted on the cup so as to extend circumferentially around the cup.

Abstract: A burner assembly for a radiant tube heater having an air duct portion for passage of combustion air to a radiant tube portion includes a mixing cup for mixing combustible gas and air and delivering the mixture to the tube. This cup has an inlet portion and a larger cylindrical outlet portion. Air inlet holes are formed in an upstream end wall of the outlet portion and air ports are formed in a peripheral wall of the inlet portion. An air diverter mounted at an upstream end of the inlet portion has a set of blade which divert a portion of the air through the ports for initial mixing with the gas while a second portion of the air flows through the inlet holes providing additional primary air for mixing. An airflow restricting plate can be mounted on the cup so as to extend circumferentially around the cup.

Abstract: A pitot tube assembly is provided for a radiant tube heater having a blower for providing combustion air to a burner. The assembly includes a mounting plate for attaching the assembly to a wall of a housing of the blower. First and second, substantially L-shaped pitot tubes extend through the mounting plate and are connected thereto and have respective inner leg sections which are arranged within an outlet section of the blower during use of the radiant tube heater. These leg sections extend in opposite directions to their respective pressure sensing ends. The first pitot tube measures impact pressure created by the blower and the second pitot tube measures static pressure. These tubes are connectible to a differential pressure switch arrangement for controlling operation of the burner. As part of a burner assembly, there is a mixing cup unit mountable within the burner tube of the heater and capable of mixing primary air and combustible gas. A gas valve unit regulates flow of the gas to the cup assembly.

Abstract: A radiant tube heater has a tubular arrangement with an air duct portion forming a combustion air passage and a radiant tube portion which is heated by and surrounds a laminar flame. An inlet end of the air duct portion receives combustion air from a blower. A burner assembly mounted in the air duct portion includes a burner nozzle and a burner head for mixing gas and combustion air, this head having an inlet portion and an outlet portion wider than the inlet portion. A perforated restricting plate is mounted in the air duct portion and extends around the burner head. Air holes in this plate are sized and distributed so that the plate increases flow of combustion air through openings formed in the side of the inlet portion and allows combustion air to flow in the annular passage between the outlet portion and the air duct portion.