An exhaust treatment system may include a burner, a flame sensor assembly and a control module. The flame sensor assembly may be at least partially disposed within the burner and may include an insulator and an electric heating element in heat transfer relation with the insulator. The control module may be in communication with the flame sensor assembly. The control module may determine whether a flame is present in a combustion chamber based on feedback from the flame sensor assembly. The control module may detect contamination on the insulator based on feedback from the flame sensor assembly. The control module may operate the heating element in a first mode in response to detection of a contamination in which the control module causes electrical power to be applied to the heating element to raise a temperature of the heating element to burn contamination off of the insulator.

A wheat variety designated W030377L1, the plants and seeds of wheat variety W030377L1, methods for producing a wheat plant produced by crossing the variety W030377L1 with another wheat plant, and hybrid wheat seeds and plants produced by crossing the variety W030377L1 with another wheat line or plant, and the creation of variants by mutagenesis or transformation of variety W030377L1. This invention also relates to methods for producing other wheat varieties or breeding lines derived from wheat variety W030377L1 and to wheat varieties or breeding lines produced by those methods.

A fastening assembly includes a connecting member, a mounting member mounted to the connecting member, and a sliding member. The mounting member includes a first fixing portion. The sliding member is slidably received in the mounting member and the connecting member. The sliding member includes a first end exposed out of the first fixing portion, and a second end slidably received in the connecting member. The second end of the sliding member is operable to be extended out of or substantially coplanar with an end of the connecting member. The fastening assembly can be utilized to mount a heat sink to a board.

A steam cooled chemical reactor (1) comprising a vertical vessel (2), a plate heat exchanger embedded in a catalytic bed, to cool the catalytic bed by evaporation of a cooling water flow, wherein a water inlet and a steam outlet are located underneath the heat exchanger, and the plates and related piping are arranged so that the path of the cooling flow comprises a first ascending path from bottom to top of the catalytic bed, and a second descending path from top to the bottom of catalytic bed, and wherein internal evaporation channels of the plates provide the second descending or the first ascending path, and water upcomers or respectively steam downcomers provide the other of said first and second path.

A power supply can provide brown-out protection and overheat protection. The power supply includes a rectifier, a transformer, and a power management device. The rectifier is used for receiving an alternating current voltage. The alternating current voltage has a voltage cycle. The transformer coupled to the rectifier has an inductor coupled to a switch for supplying an output voltage. The power management device is used for controlling the switch to make the inductor save power or release power. The power management device has a multi-functional pin coupled to the rectifier for receiving a detection voltage corresponding to a positive half cycle of the alternating current voltage. The multi-functional pin is also coupled to a thermistor for receiving an overheat protection signal.

Technologies are described herein for utilizing a head heater to test temperature stability of a head of a storage device and to prevent the head from operating in an unstable temperature condition. A first power level may be applied to a head heater of a head in a storage device, the first power level configured to simulate a temperature condition in the head. An instability of the head is determined and the temperature condition and the instability of the head are recorded in a memory. The process may be repeated to develop a range of temperature conditions in which the head exhibits instability. The range of temperature conditions and the head heater may then be utilized to prevent the head from operating in an unstable temperature condition during normal operation.

In a heat-assisted magnetic recording (HAMR) hard disk drive, a heat-dissipating head slider assembly is described in which the slider is stepped on the disk-opposing side and a HAMR laser module is mounted on the lower surface to assist with dissipation of heat from the laser. The lower surface is a surface of the main body of the slider and is composed primarily of a first material, and the slider may include a heat-dissipating plate that forms the higher stepped surface, where the plate is composed of a second material that has a higher thermal conductivity than the first material, such as silicon.

An apparatus includes a write element configured to apply a magnetic field to write data on a portion of a heat-assisted magnetic recording media in response to an energizing current. An energy source is configured to heat the portion of the media being magnetized by the write element. A preheat energizing current is applied to the write element during an interval before writing the data to the portion of the media. The preheat energizing current does not cause data to be written to the media and brings at least one of the write element and driver circuitry into thermal equilibrium prior to writing the data on the portion.

In a heat-assisted magnetic recording hard disk drive, one or more thermally conductive features are incorporated to assist with dissipation of heat from a laser module that comprises a laser and a submount. The submount may be coupled to the slider with solder covering a wider adhesive area for enhanced conduction of heat away from the laser module and to the slider, one or both of the submount and the laser may include a surface coating that increases the thermal radiation of the corresponding component, and/or one or both of the submount and the laser may include fins configured to transfer heat from the corresponding component. Further, a HAMR HGA may be configured such that the submount is coupled directly to the suspension flexure using a thermally conductive material, for conduction of heat away from the laser module and to the flexure.

Apparatus and method are provided for electric induction heating and/or stirring of a molten electrically conductive composition in a containment vessel with the apparatus being removably insertable in the molten composition. An induction coil embedded in refractory or a coating is submerged in the composition and used to heat and/or stir the molten composition either externally or internally to the refractory or coating.

Apparatus and process for heating and melting a material in a susceptor vessel are provided wherein phase synchronized ac voltage is supplied from a separate power source to each one of at least two induction coils in separate zones around the vessel. Power magnitude from each source to an induction coil is controlled by pulse width control of the source's output voltage. Output frequency from each source is either fixed or variable based upon the electrically conductive state of the material. Optional electromagnetic stirring is achieved by establishing a phase shift between the voltage outputs of the power supplies after the material in the susceptor vessel has melted.

A heating electrode assembly for a crystal growth furnace includes: a heat insulation board unit that is disposed between a furnace wall and a heater, that includes a first surface facing the furnace wall and a second surface facing the heater, and that is formed with a hole extending through the first surface and the second surface; an electrode unit that includes an electricity input portion mounted to the furnace wall, a post portion disposed in the hole, and an abutment flange connecting the post portion and the heater; and an electrical insulating unit including a tubular sleeve that is disposed in the hole and that surrounds the post portion, and a pad that is clamped between the abutment flange and the second surface.

Disclosed herein are a graphite crucible for electromagnetic induction-based silicon melting and an apparatus for silicon melting/refining using the same, which performs a melting operation by a combination of indirect melting and direct melting. The crucible is formed of a graphite material and includes a cylindrical body having an open upper part through which a silicon raw material is charged into the crucible, and an outer wall surrounded by an induction coil, wherein a plurality of slits are vertically formed through the outer wall and an inner wall of the crucible such that an electromagnetic force created by an electric current flowing in the induction coil acts toward an inner center of the crucible to prevent a silicon melt from contacting the inner wall of the crucible.

Systems and methods are provided for a high performance heater. In an embodiment, the high performance heater comprises a first stackable tray comprising a first alignment pin that insulates a first heating element disposed in the first stackable tray; a second stackable tray comprising a second alignment pin that insulates a second heating element disposed in the second stackable tray, wherein a top of the first alignment pin fits into a cutout of a bottom of the second alignment pin when the first and second stackable trays are stacked, and wherein the first and second stackable trays comprise one or more materials, an outer diameter and an inner diameter, and wherein an area between the outer diameter and the inner diameter of the stackable trays comprises at least one cutout portion that allows expansion of the material(s) when the high performance heater is at high temperatures.

This invention is provided for improvement of corrosion-resistant property of a crucible and for promotion of safety in a pyrochemical reprocessing method for the spent nuclear fuel. The spent nuclear fuel is dissolved in a molten salt placed in the crucible. In a pyrochemical reprocessing method, the nuclear fuel is deposited, and the crucible (2) is heated by induction heating. Cooling media (5, 6) are supplied to cool down, and a molten salt layer (7) is maintained by keeping balance between the heating and the cooling, and a solidified salt layer (8) is formed on inner wall surface of the crucible.

Length adjustment can be performed in a simple manner and without impairment of the insulating effect in an insulation cassette for the heat insulation of elongated elements. A multilayer insulation includes flat reflection elements (21, 22). Each layer of the insulation has at least two of the flat reflection elements (21, 22), which overlap at least partly at their ends (24) facing each other.

A heat-assisted magnetic recording (HAMR) air-bearing slider has an optically-transparent protective film over the near-field transducer (NFT) to protect the NFT from excessive heat caused by the accumulation of carbonaceous material on the slider's overcoat. The NFT is thus separated from the overcoat by the protective film. The protective film does not cover the write pole end, which is covered only by the overcoat, so there is no spacing loss between the write pole end and the recording layer on the disk. In one embodiment the protective film is coplanar with the recording-layer-facing surface of the slider and the overcoat covers both the protective film and the write pole end. In another embodiment the overcoat has a window that surrounds the protective film, with the protective film being substantially coplanar with the air-bearing surface (ABS) of the slider. In both embodiments the smooth topography of the slider's ABS is maintained.

A heated cosmetic applicator that has a plurality of small, individual heating elements placed within and/or on at least some of the lash grooming elements. A heat-generating applicator head for a heated cosmetic applicator that has a plurality of small, individual heating elements placed within and/or on at least some of the lash grooming elements.

A tractor cab HVAC system has a blower (22) which draws air into the system via air intake means (13) in the roof (14) of the cab (10). Ducting (15) in the roof of the cab directs air drawn in via the intake means down the center of one or more hollow adjacent pillars (16) of the cab to an air filter (18) contained in a housing (20) located between the adjacent pillars. Further ducting (19) extends from the air filter housing to an HVAC unit (11), the HVAC unit processing the air drawn into the system prior to discharging the processed air into the cab. The filter housing (20) is of generally rectangular form and is connected at opposite ends to the two hollow adjacent pillars (16) of the cab via inlet openings (20a) in the housing to allow the passage of intake air from the pillars to the filter (18).

The present invention is directed to apparatus and methods for cooling computer servers and/or electrical equipment in a rack device for data centers or telecommunication centers.

The present invention relates to an aluminum extrusion heat sink structure and a corresponding backlight module. The aluminum extrusion heat sink structure comprises a light source connecting portion, a back plate connecting portion and a light guide plate support portion. The manufacture cost of the aluminum extrusion heat sink structure is lower, and the heat dissipation effect is better, so as to solve the technology problem that the volume of a traditional aluminum extrusion heat sink structure is larger caused the cost of the aluminum extrusion heat sink structure and the corresponding backlight module is higher.

A lamp includes an outer shell having heat conductivity, a base provided in the outer shell, and a cover provided in the outer shell. The outer shell has a light source support, and a heat radiating surface exposed to the outside of the outer shell. The light source support is formed integral with the heat radiating surface. A light source is supported on the light source support. The light source is heated during lighting, and thermally connected to the light source support. The light source is covered with the cover.

A system for a thermal manufacturing system including a heliostat and a mold. The heliostat includes at least one reflecting surface, a steering mechanism and a controller. The steering mechanism is coupled to the at least one reflecting surface and capable of directing at least a first portion of the at least one reflecting surface toward a first one of multiple, selectable focal points. The mold is located in a second one of the selectable focal points. A manufacturing method is also disclosed.

An axial resistance sheathed heater is presented. The axial resistance sheathed heater includes a retaining sheath having a first end and a second end and a resistance wire completely disposed within the retaining sheath. The heater further includes a first conductor rod partially disposed within the retaining sheath and extending beyond the first end of the retaining sheath, the first conductor rod in direct electrical communication and direct mechanical communication with the resistance wire; and a second conductor rod partially disposed within said retaining sheath and extending beyond the second end of the retaining sheath, the second conductor rod in direct electrical communication and direct mechanical communication with the resistance wire. The resistance wire, the first conductor rod and the second conductor rod comprise a circuit achieving a power to voltage rating of about 5000:24.

A heater assembly includes one or more first heating elements, the one or more first heating elements being characterized by a positive temperature coefficient; and one or more second heating elements, the one or more second heating elements comprising resistance wire elements. The one or more second heating elements are positioned in proximity to the one or more first heating elements such that at least one of the one or more second heating elements is configured to, upon being powered on, pre-heat at least one of the one or more first heating elements before the at least one first heating element is powered on.

A surface mount chip resistor for increasing power handling capabilities of radio frequency (RF) circuits and for minimizing parasitic capacitance and inductance effects, the chip resistor includes a ceramic substrate having a main portion and an outrigger. A resistor element is between an input contact and an output contact on a top surface of the main portion. A ground plane attachment area is on a top surface of the outrigger. The ground plane attachment area is mounted to a ground plane of a circuit board to provide a heat pathway for dissipating heat generated by the resistor element.

There are provided a substrate for an inkjet head and an inkjet head wherein in a case where a protection layer of heating resistors is energized, an electrical connection with portions around the protection layer is more reliably cut. A first protection layer provided for the substrate for an inkjet head includes individual sections provided at positions corresponding to the plurality of heating resistors and a common section which commonly connects the plurality of individual sections. The individual sections and the common section are connected via connect sections which are eluted and connect in a case where an electrochemical reaction occurs between the connect sections and ink when electricity flow therethrough, so that an electrical connection between the individual sections and the common section is cut.

A rotation speed control circuit is disclosed. The rotation speed control circuit includes a temperature-controlled voltage duty generator, a pulse-width signal duty generator, a multiplier and a rotation speed signal generator. The temperature-controlled voltage duty generator converts temperature-controlled voltage to digital temperature-controlled voltage and executes linear interpolation operation according to a first setting data so as to output temperature-controlled voltage duty signal. The pulse-width signal duty generator coverts pulse-width input signal to a digital pulse-width input signal and executes linear interpolation operation according to a second setting data so as to output a pulse-width duty signal. The temperature-controlled voltage duty signal and the pulse-width duty signal are executed for multiplication by the multiplier so as to output mixing-duty signal. The rotation speed generator receives the mixing-duty signal and a third setting data, and executes a minimum output duty operation so as to output a pulse-width output signal.

An apparatus for endosurgical use includes an instrument having an end effector and a staple cartridge insertable into the end effector. The staple cartridge includes staples, staple apertures, a resistive member, and a medical fluid. When coupled to a power source, the medical fluid is vaporized by the resistive member and expelled out the staple apertures onto the stapled tissue. The power source may be contained within the instrument. In one configuration, a resistive strip with strip contacts may electrically couple to a conductor in the end effector. The medical fluid may also be divided into a plurality of sealant pads corresponding to the staple apertures, and the medical fluid may be a depolymerizable cyanoacrylate, a sprayable thermoplastic urethane, or any vaporizable medicament or pharmaceutical. The staple drivers may include one or more apertures to permit the medical fluid to pass through or around the staple drivers.

Isolated wheat proteins that are substantially free of sulfites and compositions formed from the isolated wheat proteins are described. Methods of forming compositions which include isolated wheat proteins that are substantially free of sulfites are also described.

In order to solve the numerous problems with existing steam, vacuum, and hot water heating systems, presented are novel systems and methods of vapor vacuum heating having several improvements over the prior art, including: condensate return which can operate without steam traps; naturally-induced vacuum; improved vacuum pump operation for sustaining vacuum in such systems; liquid lift apparatus for use with such systems; and other improvements. All innovations presented herein make vapor vacuum heating more efficient and economical for industrial, commercial, and home applications. A field test conducted with these innovations show results of about 26-50% reduced energy usage, implying significant energy savings from the use of the present invention over current heating systems.

The scroll refrigeration compressor includes a sealed casing, stationary and moving volutes including spiral wraps engaged in one another and defining the variable-volume compression chambers, a delivery chamber defined by the plate of the stationary volute and the sealed casing, a heat shield disposed in the delivery chamber and dividing the delivery chamber into a first volume defined by the plate of the stationary volute and the heat shield and a second volume defined by the heat shield and the sealed casing, and at least one flow passage arranged to communicate the first and second volumes. The compressor further includes at least one bypass passage arranged to communicate the first volume with an intermediate compression chamber, and at least one bypass valve disposed in the first volume and movable between closing and opening positions for closing and opening the corresponding bypass passage.

A heat dissipating module includes a housing, a first fan and a second fan. The housing has a partition. The first fan is disposed at a side of the partition, and the second fan is disposed at the other side of the partition. The second fan has a plurality of wind deflectors, which are disposed higher than the partition.

A heat dissipation device of a light engine for a projector has a housing, a fan module, a light engine and a heat sink. The light engine is positioned in the housing and connected to the heat sink. The heat sink is positioned out of the housing. The housing has a fan-enclosed flow channel attached on an outer surface of the housing. The fan module is guided by the fan-enclosed flow channel to the heat sink to enhance heat dissipation efficiency of the light engine for the projector.

An apparatus includes a head transducer configured to interact with a magnetic recording medium and a heater configured to thermally actuate the head transducer. A thermal sensor at or near the head transducer is configured to produce a sensor signal. Circuitry is coupled to the heater and configured to cause an oscillation in heater power. The heater power oscillation causes an oscillation in the sensor signal. A detector is coupled to the thermal sensor and configured to detect head-medium contact using the oscillating sensor signal and heater power.

A forging heat resistant steel of an embodiment contains in percent by mass C: 0.05-0.2, Si: 0.01-0.1, Mn: 0.01-0.15, Ni: 0.05-1, Cr: 8 or more and less than 10, Mo: 0.05-1, V: 0.05-0.3, Co: 1-5, W: 1-2.2, N: 0.01 or more and less than 0.015, Nb: 0.01-0.15, B: 0.003-0.03, and a remainder comprising Fe and unavoidable impurities.

The present invention provides a system and method for reclaiming energy from the heat emanating from spent nuclear fuel contained within a canister-based dry storage system. The inventive system and method provides continuous passive cooling of the loaded canisters by utilizing the chimney-effect and reclaims the energy from the air that is heated by the canisters. The inventive system and method, in one embodiment, is particularly suited to store the canisters below-grade, thereby utilizing the natural radiation shielding properties of the sub-grade while still facilitating passive air cooling of the canisters. In another embodiment, the invention focuses on a special arrangement of the spent nuclear fuel within the canisters so that spent nuclear fuel that is hotter than that which is typically allowed to be withdrawn from the spent fuel pools can be used in a dry-storage environment, thereby increasing the amount energy that can be reclaimed.

A sheathed, annular metal fuel system is described. A metal fuel pin system is described that includes an annular metal nuclear fuel alloy. A sheath may surround the metal nuclear fuel alloy, and a cladding may surround the sheath. A gas plenum may also be present. Mold arrangements and methods of fabrication of the sheathed, annular metal fuel are also described.

A plug for heat-conducting tubes is equipped with: a plug main body, which is formed so as to be capable of being inserted into the heat-conducting tubes; a columnar member, which is capable of being inserted into and removed from the plug main body from the cylindrical open end of the plug main body, and has at its outer circumference a tapered surface; and a wedge member, which is formed so as to be capable of being inserted into and removed from the plug main body from the cylindrical open end of the plug main body, and has at its inner circumference a tapered surface which opposes the tapered surface of the columnar member when the wedge member is inserted into the plug main body.

The invention relates to a nuclear fuel cladding totally or partially made of a composite material with a ceramic matrix containing silicon carbide (SiC) fibers as a matrix reinforcement and an interphase layer provided between the matrix and the fibers, the matrix including silicon carbide as well as at least one of the following additional carbides: titanium carbide (TiC), zirconium carbide (Zrc), and ternary titanium silicon carbide (Ti3SiC2). When irradiated and at temperatures of between 800° C. and 1200° C., said cladding can mechanically maintain the nuclear fuel within the cladding while enabling optimal thermal-energy transfer towards the coolant. The invention also relates to a method for making the nuclear fuel cladding.

Process for preparing hydrocyanic acid by catalytic dehydration of gaseous formamide, wherein the dehydration of formamide is coupled with an exothermic reaction by the reactor used in the dehydration comprising two separate fluid paths which are separated by a common reactor wall, with one fluid path being provided for the dehydration of formamide and the second fluid path being provided for the exothermic reaction.

A highly reliable vacuum heat insulating material having excellent processability, usability and heat insulating performance and a heat insulating box using the vacuum heat insulating material are provided. A vacuum heat insulating material related to the present invention includes: a core material structured by a laminated structure of an organic fiber assembly formed by forming an organic fiber into a sheet shape and cutting an end face with a predetermined length, and having a core material opening portion formed by a through hole or a notch with cutting; a gas-barrier outer cover material containing the core material inside, having a sealing portion for sealing surrounding of the sheet-shaped organic fiber assembly and surrounding of the core material opening portion, and hermetically sealing an inside with almost vacuum status by sealing the sealing portion; and an outer cover material opening portion provided at the outer cover material under a status in which the sealing portion provided at the surrounding of the sheet-shaped organic fiber assembly and the surrounding of the core material opening portion is sealed, being a through hole or a notch which is smaller than the core material opening portion with a sealed amount, and a long fiber being equal to or longer than a length of the sheet is used for the organic fiber.

A polymeric woven bag has a first panel and a second panel and an open end of the bag to be pinched closed. A first layer of heat activated adhesive material is on a portion of the bag to form an adhesive-to-adhesive seal by contact with a second layer of heat activated adhesive material on a portion of the bag, wherein a chemical family of the adhesive layers comprises polyolefin thermoplastic components, and wherein the first adhesive layer and the second adhesive layer have respective heat activation temperatures below the softening point temperature of the polymeric bag material.

A method for converting heat to electric energy is described which involves thermally cycling an electrically polarizable material sandwiched between electrodes. The material is heated by extracting thermal energy from a gas to condense the gas into a liquid and transferring the thermal energy to the electrically polarizable material. An apparatus is also described which includes an electrically polarizable material sandwiched between electrodes and a heat exchanger for heating the material in thermal communication with a heat source, wherein the heat source is a condenser. An apparatus is also described which comprises a chamber, one or more conduits inside the chamber for conveying a cooling fluid and an electrically polarizable material sandwiched between electrodes on an outer surface of the conduit. A gas introduced into the chamber condenses on the conduits and thermal energy is thereby transferred from the gas to the electrically polarizable material.

A method for converting heat to electric energy is described which involves thermally cycling an electrically polarizable material sandwiched between electrodes. The material is heated using thermal energy obtained from: a combustion reaction; solar energy; a nuclear reaction; ocean water; geothermal energy; or thermal energy recovered from an industrial process. An apparatus is also described which includes an electrically polarizable material sandwiched between electrodes and a heat exchanger for heating the material. The heat source used to heat the material can be: a combustion apparatus; a solar thermal collector; or a component of a furnace exhaust device. Alternatively, the heat exchanger can be a device for extracting thermal energy from the earth, the sun, ocean water, an industrial process, a combustion reaction or a nuclear reaction. A vehicle is also described which comprises an apparatus for converting heat to electrical energy connected to an electric motor.

A method for producing process vapor and boiler feed steam in a heatable reforming reactor for producing synthesis gas. The sensible heat of a synthesis gas produced from hydrocarbons and steam can be used so that two types of vapor are produced during the heating and evaporation of boiler feed water and process condensate. The method also includes a conversion of the carbon monoxide contained in the synthesis gas. The method includes an optional heating of the boiler feed water using the flue gas from the heating of the reforming reactor. The sensible heat of the synthesis gas and of the flue gas originating from the heating can be used more efficiently. The disadvantages from the flue gas heating, which are caused by the fluctuating heat supply in the flue gas duct, are avoided. A system for practicing the method is also disclosed.

A heating system comprising a fuel burner in co-operation with a primary heat exchanger, a reservoir for storing warmed water in, and a blending valve, and a controller wherein in use a user can signal to the controller to warm the water in the water store using a heater or by the primary heat exchanger, and when hot water is required water is removed from the water store and mixed with water from a cold main prior to being or after the water from the cold main has been admitted to a further heat exchanger for heating the water.

A robotic tubesheet walker having two rails connected by a central hinge, wherein the central hinge can be opened or closed by an actuation device. Upon each rail is mounted a carriage, wherein each carriage can move along its respective rail toward or away from the central hinge by means of a drive mechanism. Each carriage further contains at least two “gripper” attachment mechanisms, such as camlocks, to grip the tubesheet. The grippers either insert into tube holes within the tubesheet to fasten the respective carriage to the tubesheet, or retract to disengage. Further attached to the central hinge is a tool support fixture, and attached to the tool support fixture is a coupler that holds maintenance or inspection tools.

A fluid heating system for heating and dispensing fluid in a primary fluid flow path is disclosed, and may include a reservoir defining an interior for holding a quantity of a fluid, with the interior being in fluid communication with the primary fluid flow path such that the quantity of fluid in the interior is able to flow into the primary fluid flow path. A primary pump may be configured to pump fluid in the primary fluid flow path, the primary pump being in fluid communication with the primary fluid flow path. A fluid dispensing device may be configured to selectively dispense fluid from the primary fluid flow path. A steam injection apparatus may be in communication with the interior of the reservoir device to inject steam into the interior to heat fluid located in the interior of the reservoir.

A catalytic tank heater includes a catalytic heating element supported on an LPG tank by a support structure that holds the element in a position facing the tank. Vapor from the tank is provided as fuel to the heating element, and is regulated to increase heat output as tank pressure drops. The heating element is internally separated into a pilot heater and a main heater, with respective separate fuel inlets. The pilot heater remains in continual operation, but the main heater is operated only while tank pressure is below a threshold. Operation of the pilot heater keeps a portion of the catalyst hot, so that, when tank pressure drops below the threshold, and fuel is supplied to the main heater, catalytic combustion quickly expands from the area surrounding the pilot heater to the remainder of the catalyst.