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EP0011457A2 - Appareil de combustion pulsatoire - Google Patents

Appareil de combustion pulsatoire Download PDF

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Publication number
EP0011457A2
EP0011457A2 EP79302521A EP79302521A EP0011457A2 EP 0011457 A2 EP0011457 A2 EP 0011457A2 EP 79302521 A EP79302521 A EP 79302521A EP 79302521 A EP79302521 A EP 79302521A EP 0011457 A2 EP0011457 A2 EP 0011457A2
Authority
EP
European Patent Office
Prior art keywords
chamber
combustion
combustion chamber
inlet
coils
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP79302521A
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German (de)
English (en)
Other versions
EP0011457B1 (fr
EP0011457A3 (en
Inventor
John A. Kitchen
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Individual
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Individual
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Filing date
Publication date
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Priority claimed from US05/960,975 external-priority patent/US4241723A/en
Priority claimed from US06/006,702 external-priority patent/US4241720A/en
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Publication of EP0011457A2 publication Critical patent/EP0011457A2/fr
Publication of EP0011457A3 publication Critical patent/EP0011457A3/en
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Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C15/00—Apparatus in which combustion takes place in pulses influenced by acoustic resonance in a gas mass
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/18—Water-storage heaters
    • F24H1/20—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes
    • F24H1/205—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes with furnace tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/18—Arrangement or mounting of grates or heating means
    • F24H9/1809—Arrangement or mounting of grates or heating means for water heaters
    • F24H9/1832—Arrangement or mounting of combustion heating means, e.g. grates or burners
    • F24H9/1836—Arrangement or mounting of combustion heating means, e.g. grates or burners using fluid fuel

Definitions

  • This invention relates to pulse combustion apparatus and to heaters of the pulse combustion type.
  • a pulse combustion apparatus conventionally includes a combustion chamber and an exhaust pipe which forms a resonant system with the combustion chamber.
  • a fuel charge is admitted to the combustion chamber and is ignited.
  • the charge expands into the exhaust pipe causing a partial vacuum transient in the combustion chamber which both assists in drawing in a fresh charge, and causes high temperature gas to be drawn back into the combustion chamber from the exhaust pipe.
  • the fresh fuel charge spontaneously ignites establishing the next cycle and the apparatus is self- sustaining after initial ignition.
  • a heater of the pulse combustion type a fluid to be heated is brought into heat exchange relationship with the exhaust pipe.
  • My United States Patent No. 3,267,985 discloses pulse-combustion-type heater in which the combustion chamber has substantially the shape of two conical shells joined together at their major diameters along a common line of juncture.
  • Five exhaust pipes are coupled to the combustion chamber for heating and are disposed in a chamber through which water is circulated. While this form of combustion chamber and exhaust system has been found to provide a very stable combustion cycle, the present invention is aimed at providing further improvements intended to enhance performance.
  • a pulse combustion apparatus includes a combustio- chamber, at least one exhaust pipe forming a resonant system with the combustion chamber, means for admitting successive fuel charges to said chamber, and ignition means operable to initiate combustion in the chamber.
  • the combustion chamber has an internal cavity of a shape which extends about a median plane, which is circular in said plane, and which curves generally inwardly from both of said plane around its entire periphery, towards first and second ends of the cavity.
  • An inlet is providec at one of said ends, through which successive fuel charges can enter the combustion chamber from said fuel charge admitting means in a direction generally normal to said median plane of the combustion chamber.
  • the combustion chamber also includes an exhaust gas outlet disposed in said median plane.
  • the exhaust pipe is coupled to said exhaust gas outlet and extends from the combustion chamber generally tangentially with respect to said cavity.
  • a pulse combustion heater is generally indicated at 20 and includes a combustion chamber 22, valve means 24 at the top of the chamber for admitting fuel charges thereto, and an exhaust system 26.
  • the components of the apparatus are disposed within a housing 28 which is designed to be self- standing on a suitable support surface.
  • Reference numeral 30 indicates a control box which is disposed at one side of the housing and which houses suitable control equipment including an ignition transformer connected by a high tension lead (not shown) to a spark plug in the combustion chamber. The spark plug is used for starting only.
  • Housing 28 is divided internally as will be described to define, from top to bottom, an air inlet chamber 32, an air cushion chamber 34, a heat exchange chamber 36, a muffler chamber 38 and an exhaust chamber 40.
  • the housing is defined by inner and outer casings. denoted 42 and 44 respectively.
  • the inner casing is made of high strength concrete, while the outer casing is made of steel.
  • the inner casing is fitted with a liner 46 of galvanized steel.
  • the top of chamber 34 is defined by a plate 48 which separates the air cushion chamber 34 from the air inlet chamber 32. Supporting structure above plate 48 is generally indicated at 50 but will not be described in detail.
  • suitable sound insulating material is incorporated in the top of the housing and in the inner casing, but has not been shown, again because it forms no part of the invention.
  • Air inlet chamber 32 communicates with the exterior of the housing by way of an air inlet 52 which extends through the inner and outer casing. This allows ambient air or air from a supply pipe to be drawn into the housing for combustion as required.
  • a fan unit generally denoted 54 is suspended below plate 48 and has an inlet 56 within chamber 32.
  • the fan unit includes an electric motor 58 driving fan blades 60 arranged within a fan chamber 62 which discharges into the air cushion chamber 34. This chamber provides a reservoir of combustion air. Air is drawn from chamber 34 into the combustion chamber 22 as required under the control of the valve means generally indicated at 24.
  • Fan unit 54 is used only for starting; after ignition, the combustion process is self- aspirating.
  • Heat exchange chamber 36 is defined by a liner assembly generally denoted 64, which, in effect, forms a boiler inside housing 28.
  • the liner assembly includes a cylindrical portion 65 and top and bottom closures or “heads” 66 and 68 respectively at opposite ends of the heat exchange chamber and that the chamber is provided with an inlet 70 and an outlet 72 which extend through housing 28.
  • Each of these components is in the form of a tubular sleeve which passes through the housing 28 and communicates with an associated pipe connection which mates with a corresponding opening in the relevant closure member of liner assembly 64.
  • the pipe connection associated with inlet 70 is denoted 76 and the associated opening in the top closure 66 is indicated at 78.
  • the corresponding pipe connection for outlet 72 is denoted 80 and the corresponding opening is indicated at 82.
  • the inlet and outlets are coupled to external equipment (not shown) for circulating water through a heat exchange chamber 36 for heating.
  • the combustion chamber 22 is mounted in an opening 74 in the top closure 66 of the liner assembly 64 so that water entering the heat exchange chamber 36 through inlet 70 will flow around the combustion chamber for transfer of heat from the to the water. Similarly, as the water flows down in chamber 36 towards outlet 72, it will flow around the exhaust system 26 and receive heat therefrom.
  • Muffler chamber 38 is defined between the lower closure member 68 of liner assembly 64 and a plate 84 which extends transversely inside housing 28 at a spacing below the bottom closure member 68.
  • the exhaust system 26 discharges generally vertically downwards into chamber 38 as will be described and a heat shield 86 is attached to the upper surfaces of plate 84.
  • a muffler tube 88 extends generally vertically through plate 84 at a position spaced laterally from the position at which the exhaust system discharges into chamber 38.
  • Chamber 40 has an exhaust outlet pipe 90 through which the exhaust gases leave housing 28 and from which the gases may be vented to atmosphere or otherwise disposed of as appropriate.
  • a narrow condensate drain tube 92 is provided at the bottom of chamber 40 and is inclined downwardly so that any liquid which may collect in the chamber will drain to the outside.
  • Combustion chamber 22 is in the form of a one-piece bronze casting, denoted 94, at the top of which the valve means 24 is located.
  • the combustion chamber has an internal cavity 96 which is generally of flattened spherical shape.
  • cavity 96 extends about a median plane 98, on which plane section III-III is taken.
  • the cavity is of a shape which is circular in said plane, and which curves generally inwardly from both sides of said plane around its entire periphery towards first and second ends 100 and 102 of said cavity.
  • Casting 94 defines atvinlet 104 at the first end of the cavity through which successive fuel charges can enter the combustion chamber cavity, while the second end 102 of the cavity is closed and generally flat.
  • An exhaust outlet 106 is provided in the wall of the combustion chamber and is located in median plane 98.
  • An integral sleeve 108 extends from the combustion chamber generally tangentially with respect to cavity 96 and a pipe 110 of the exhaust system (see later) is coupled to the sleeve.
  • the combustion chamber inlet 104 is in the form of a passageway which extends through casting 94 from a top flange 112 to cavity 96 and includes three portions 114, 116 and 118 of progressively reducing diameter considered in the direction of fuel charge flow. As will be seen from Figure 4, the flange 112 and passageway portions 114, 116 and 118 are of circular shape in plan.
  • the center passageway portion 116 receives a flame trap 120 for preventing blow-back of burning gases through the combustion chamber inlet.
  • Flame trap 120 is in the form of an outer tubular retainer 122 and a core 124 formed of a spiral of corrugated stainless steel strip; the corrugations leave openings between the turns of the spiral through which fuel charges can flow.
  • a screw threaded opening 125 adjacent inlet 104 receives a spark plug (not shown) for initiating the combustion process.
  • valve means 24 includes a valve plate 126 mounted on the top surface of the flange 112 of casting 94.
  • Plate 126 is provided with a number of sets of openings for admitting charges of air and fuel such as natural gas to the combustion chamber.
  • the sets of openings are denoted by reference numeral 128 and it will be seen that five such sets are visible; in fact, plate 126 is provided with seven sets of valve openings although two of the sets do not appear in Figure 4.
  • Each set of openings includes a central opening 130 for admitting natural gas and a plurality of openings 131 distributed around opening 130 and through which air is admitted to the combustion chamber.
  • Each central opening 130 is fitted with an inlet tube 132 which extends vertically upwardly from plate 126.
  • the tubes 132 communicate with a gas cushion chamber defined by a casing 134 which in this case is made of sheet brass.
  • the gas cushion chamber is of generally cylindrical shape with domed ends (although the particular shape is not critical) and is fitted at one end with a corrugated fuel inlet tube 136 which extends through housing 28 and communicates outside the housing with a source of natural gas (not shown).
  • the gas cushion chamber 134 will provide the combustion chamber with what is, in effect, a reservoir of gas at source pressure for admission to the chamber through the fuel inlet tubes 132
  • Air cushion chamber 34 provides a similar reservoir of combustion air.
  • a pressure sensing tube 138 is shown adjacent the air cushion chamber 134 in Figure 1 and can be connected to switch in control box 30 for indicating when combustion has been established. Means (not shown) may also be provided for maintaining a substantially constant air/fuel ratio as described by my United States Patent No. 3,267,985.
  • the sets 123 of openings in plate 126 are controlled by individual valves, each of which includes a light and freely movable valve disc such as those shown in exploded positions at 140 in Figure 4.
  • the discs are made of Dacron (T.M.) fabric coated with polychloro- trifluorethylene sold under the trade mark Kel-F by M. W. Kellog Co.
  • Each disc 140 is retained below the associates set of openings by a support plate 142 suspended from valve plate 126.
  • Each support plate 142 is of circular shape and is formed with a set of openings corresponding generally to the openings in plate 126.
  • Three integral lugs 144 project upwardly from plate 142 for suspending the plate.
  • each valve disc 140 is supported by the associated plate 142 and is trapped against lateral movember by lugs 144.
  • the openings in plate 142 permit pressure waves from the combustion chamber to force the valve disc 140 upwardly to close off the associated openings in valve plate 126. When the pressure decreases, the discs will move down and admit fuel to the combustion chamber.
  • FIGS 6 and 7 show the exhaust system of the heater and will now be more particularly described.
  • the system includes a single primary exhaust pipe 110 part of which is visible in Figures 3 and 4.
  • This primary exhaust pipe has an inlet end coupled to the combustion chamber so as to extend outwardly from the chamber tangentially with respect to its circular configuration.
  • Pipe 110 is of relatively substantial length (see later) and is shaped to define a generally circular loop portion which extends around the combustion chamber (see Figure 1), and an end portion which is bent downwardly and connected to a manifold 146.
  • Manifold 146 has a single central inlet to which the primary exhaust pipe 110 is coupled.
  • the inlet is defined by a sleeve 148 which projects upwardly from a main body portion 150 of the manifold and which is angled to correspond with the inclination of outlet end portion of the primary exhaust pipe 110.
  • Pipe 110 is received in and welded to sleeve 148.
  • the body portion 150 of the manifold 146 is generally cylindrical in shape and is formed with a plurality of outlets in the form of openings in its outer surface,which communicate with. the single central inlet.
  • the outlet openings are arranged in pairs in equally spaced relationship around the body portion 150 of manifold 146 with the outlets in each pair spaced vertically from one another and staggered laterally to a slight extent as can clearly be seen in Figure 6 in the case of one pair of outlet openings (denoted 152a and 152b).
  • a plurality of heat exchange coils generally denoted 154 are provided for connecting manifold 146 with the muffler chamber 38 ( Figure 1).
  • Each coil is in the form of a hollow tube shaped to define a helix of substantially constant diameter extending about a longitudinal axis and having an inlet coupled to one of said manifold outlets, and an outlet which communicates with the muffler chamber 38 of the heater.
  • the heat exchange coils are arranged in pairs around manifold 146 and each pair comprises one left hand wound coil and one right hand would coil of identical shape and size.
  • reference numeral 154L denotes the left hand coil of a pair while 154R denotes the corresponding right hand coil.
  • the corresponding pair of coils are similarly designated in Figure 7. Five such pairs of coils are provided around manifold 146.
  • a still further advantage of this heat exchanger construction is that heat exchangers having even more coils can be readily fabricated by enlarging the manifold and adding coils around the periphery of the existing coils are indicated in chain dotted line at 154' in Figure 7. These additional coils may be arranged in pairs of left and right hand coils interleaved with one another in the same fashion as the center coils. The inlet ends of the coils would be extended inwardly as shown in Figure 7 and connected into the larger manifold in a second row of staggered manifold outlets above the outlets shown in Figure 6.
  • a still further advantage of the heat exchange structure shown in the drawings derives from the fact that curved pipes are used.
  • the boundary layer effect produces, in effect, an insulating layer of stagnant air which tends to inhibit heat transfer from the pipes and reduces the efficiency of the heat exchanger.
  • the use of curved pipes minimized the boundary layer effect and increases the efficiency of the heat exchanger compared with a conventional unit having straight pipes.
  • Curved pipes also have the advantage that they are capable of accommodating thermal expansion and contraction without the need for special precautions in the construction of the heat exchanger.
  • each of the heat exchange tubes is shaped to define an axially parallel end portion 154a which extends through the bottom boiler head 68 of the heat exchange liner assembly 64 (see Figure 1).
  • the apparatus is designed to be self- sustaining after initial starting.
  • a supply of fuel and air is delivered to the combustion chamber from the gas cushion chamber 134 and from the fan 54 respectively and is ignited by the spark plug in the combustion chamber.
  • the pressure rise which occurs in the chamber upon ignition causes the valve discs 140 ( Figure 4) to be propelled upwardly and close off the air and gas inlet openings in the valve plate 126.
  • the combustion gases expand and enter the primary exhaust pipe 110, causing a vacuum transient in the combustion chamber itself.
  • This allows the valve discs 140 to move downwardly under the effect of the pressurized air and fuel acting on the discs from above so that a fresh fuel charge enters the combustion chamber.
  • the vacuum transient also has the effect of causing combustion gases in the exhaust system to return to the combustion chamber.
  • the combustion chamber has been designed so that this returning pressure wave of combustion gases entering the combustion chamber is caused to flow in a double toroidal flow pattern as indicated diagrammatically in Figure 8.
  • the wall of the combustion chamber cavity is indicated by a chain dotted outline denoted 96 and a tangential portion of the primary exhaust pipe is indicated at 110.
  • the returning gases meet the combustion chamber wall generally in the region of the median plane. Since the wall curves inwardly at both sides of that plane, the gases are caused to flow inwardly both above and below the median plane in addition to being caused to follow the curvature of the wall around the circumference of the cavity. This generates the double toroidal flow pattern.
  • the succeeding fuel charge enters the combustion chamber from inlet 104 generally centrally of the chamber and thus enters the center of the toroidal flow pattern of the combustion gases.
  • the flow path of the fuel charge is indicated generally at 158.
  • An additional advantage derived from the combustion chamber design shown in the drawings is that the outside dimension of the combustion chamber can be minimized for a given volume, substantially reducing the space required to accommodate the combustion chamber. Another advantage is that the ratio of surface area to volume of the combustion chamber is at a minimum so as to reduce any quenching effect on the burning gases in the combustion chamber due to the presence of cooling water in the heat exchange chamber 36.
  • the design of the exhaust system has a significant impact on the operation of the apparatus.
  • the system includes a primary exhaust pipe (110) which is of relatively large diameter and is of a significant length. These characteristics are selected with the aim of ensuring that combustion is completed in the primary exhaust pipe 110 and is not carried through into the heat exchange portion of the exhaust system.
  • some combustion occurs in the exhaust system.
  • the high velocity of the gases entering the exhaust system results in a high rate of heat transfer to the surrounding water which, with the temperature drop which occurs due to expansion, results in some carbon monoxide in the gases.
  • a further expedient which may be adopted in the interest of minimizing carbon monoxide emission is to provide a restricter or nozzle (not shown) in the exhaust pipe at its connection to the combustion chamber.
  • a restricter or nozzle provides for a larger volume for secondary combustion and at the same time gives the returning pressure wave a high velocity as it enters the combustion chamber (for rapid ignition).
  • the inside diameter of the combustion chamber cavity in the median plane should be equal to or less than three times its height.
  • the inside diameter of the primary exhaust pipe should be at least about 2 cm and that the pipe should be not less than about 25 cm in length.
  • FIGS 9 and 10 illustrate a modified form of combustion chamber which may be advantageous in certain applications.
  • Primed reference numerals have been used in Figures 9 and 10 to illustrate parts which correspond with Figures 2 and 3.
  • the combustion chamber shown in Figures 9 and 10 has, in fact, been designed primarily for use in a pulse combustion apparatus in which the combustion chamber is air cooled; that is, where the apparatus is either an air cooled engine or is being used for heating air.
  • the combustion chamber is shown as having external fins denoted 160 for promoting heat transfer from the combustion chamber to the surrounding air.
  • this is only one example of an application of this form of combustion chamber and that, in other applications, the fins might well be omitted.
  • the inner wall of the combustion chamber is contoured to define an inwardly protuberant surface portion around the inner periphery of the combustion chamber in its median plane 98'.
  • the effect of this protuberant portion is to positively separate the returning combustion gases which enter the chamber cavity into two distinct flow paths.
  • the flow pattern in the chamber of Figures 9 and 10 is essentially the same as that which occurs in the combustion chamber of Figures 2 and 3, but is somewhat more discrete. This form of flow pattern may be desirable in some situations although it should be emphasized that, in practice, it has not generally been found essential to provide for physical separation of the returning gases in this fashion in order to achieve satisfactory combustion.
  • the-heater shown in these views is similar to the heater described above with reference to Figures 1 to 7.
  • the heater includes a housing, generally indicated at 200, which defines internally, an air inlet chamber 202, an air cushion chamber 204, a heat exchange chamber 206, a muffler chamber 208 and an exhaust chamber 210.
  • a fan unit 212 is positioned between the air inlet chamber 202 and the air cushion chamber 2 although the unit is shown in a partly exploded position in Figure 11.
  • a gas cushion chamber 214 is disposed within the air cushion chamber 204 and a gas supply pipe 216 is coupled to chamber 214.
  • the chamber orms part of a sub-assembly which is illustrated in detail in Figure 13, and which includes valve means of the same form as that described previously in connection with Figure 4.
  • a combustion chamber 218 is disposed in the heat exchange chamber 206 and supports the gas cushion chamber sub-assembly as will be described.
  • An exhaust system 220 is associated with combustion chamber 218 and discharges into the muffler chamber 208.
  • the combustion chamber and exhaust system are of the same form as the combustion chamber 22 and exhaust system 26 described with reference to the previous views.
  • housing 200 includes inner and outer casings, denoted 222 and 224 respectively.
  • the outer casing 224 is in the form of a one piece steel shell of cylindrical form and the inner casing 222, while also of generally cylindrical form, is an assembly of three generally cylindrical casing sections, namely an air cushion chamber section 226, a. boiler section 228, and an exhaust chamber section 230.
  • the sections are bolted together as will be described to form the inner casing 222 and are designed to provide a gas-tight assembly in which there can be no leakage of gases between the exhaust or muffler chambers of the heater and the air cushion chamber.
  • This form of inner casing also has the advantage that the heater can be manufactured as three sub-assemblies (an air. cushion chamber sub-assembly, a boiler sub-assembly, and an exhaust chamber sub-assembly) which can be easily bolted together in assenbling the heater.
  • the heater can be manufactured as three sub-assemblies (an air. cushion chamber sub-assembly, a boiler sub-assembly, and an exhaust chamber sub-assembly) which can be easily bolted together in assenbling the heater.
  • the air cushion chamber section 226 and exhaust chamber section 230 of the inner casing 222 are cast in concrete.
  • the castings may be manufactured by any appropriate concrete casting technique, e.g. by rotational moulding.
  • the sections are designed to be made by a technique in which a steel shell is employed for forming the outer surface of each section and remains associated with the concrete casting after the casting operation has been completed.
  • steel shells 226a and 230a remain around the respective castings 226 and 230 of the inner casing.
  • the casting which makes up the air cushion chamber section 226 is of generally cylindrical shape but is formed within its ends with upper and lower recesses 232 and 234 of annular form. The space between the recesses defines the air cushion chamber 204 of the apparatus.
  • Recess 232 is of significant depth compared with recess 234 and is dimensioned to define the air inlet chamber 202.
  • Recess 232 has an annular face 236 which is disposed normal to the longitudinal axis of section 226 and which forms a support for the fan unit 212 of the apparatus.
  • a cast concrete lid 238 is provided for fitting over the open upper end of section 226 and is held in place by four screw threaded studs, two of which are indicated at 240 which are cast into section 226 so as to extend upwardly from the top end face of the section.
  • the lid 238 is formed with openings to correspond with the three studs so that the lid can be fitted over the studs and secured in place by nuts and washers such as those indicated at 244.
  • Four similar studs 242 are provided at the lower end of the section.
  • a steel air inlet tube 248 is fitted into an opening which extends through casting 226 at a position above the end face 236 of recess 232. Tube 48 is secured in place by a suitable epoxy adhesive. Casting 226 is also formed with suitable openings for the gas supply pipe 216 and for other necessary external connections (see later). All of these openings are air-tightly sealed with respect to ambient air.
  • the axhaust chamber casting 230 is also of generally cylindrical shape but includes an integral wall 250 at its lower end. At its upper end, section 230 is formed with a recess 252 generally similar to and of the same diameter as the recess 234 at the lower end of the air cushion chamber section 226. Four equally spaced screw-threaded studs, two of which are visible at 254 and 256 are cast into section 230 so as to extend vertically upwardly from the top edge of the section. Internally, section 230 is shaped to define a narrow annular shoulder 258 which supports a metal muffler plate 260. Plate 260 is secured in place using a suitable silicon sealer and divides the interior of section 230 into the muffler chamber 208 and the exhaust chamber 210.
  • Plate 260 is made of steel and is fitted with a heat shield 262 and a muffler tube 264 generally similar to the structure described in connection with the first embodiment.
  • An exhaust outlet pipe 266 extends through the wall of casting 230 below plate 260 and is secured in place by an epoxy adhesive.
  • a condensate drain outlet 268 is similarly secured in an opening in the casting but below pipe 266.
  • the boiler section 228 of the inner casing of the heater is in the form of a cylindrical steel shell having an external diameter selected so that the shell can be fitted between the upper and lower casing sections 226 and 228 respectively with the respective ends of the shell received in the recesses 234 and 252 of the other two sections as shown.
  • Beads of.a suitable silicon sealer are introduced into the recesses before assembly to ensure gas-tight sealing.
  • the casing sections are then assembled and clamped together in gas-tight fashion by means of the screw-threaded studs 242 and 254 which respectively project downwardly from section 226.and upwardly from section 230.
  • Angle section brackets such as that indicated at 272 are welded to the external surface of shell 270 in positions to correspond with the positions of the studs 242 and 254.
  • Each bracket has a limb, as limb 272a, which projects outwardly from the external surface of shell 270 and which is formed with an opening for receiving the relevant stud.
  • the studs 242 and 254 project through the openings in the brackets and are fitted with suitable nuts and washers for clamping the shell 270 between the casing sections 226 and 236.
  • a suitable silicon sealer is used to coat the bottom faces of the recess 234 and 252 to ensure gas-tight sealing.
  • Shell 270 forms part of a boiler sub-assembly of the heater and is provided at its upper and lower ends with respective boiler heads 274 and 276 which are welded inside the ends of the shell in accordance with conventional boiler manufacturing practice.
  • Head 274 is formed with an opening 278 and the combustion chamber 218 is bolted to head 274 so as to protrude upwardly through opening 278.
  • the combustion chamber includes an integral flange 218a which fits against the under surface of head 274 and by which the combustion chamber is bolted to the head.
  • the exhaust system 220 of the heater will not be described in detail since it is essentially the same as the exhaust system previously described with reference to the first embodiment. For present purposes, it is sufficient to note that the exhaust. system is disposed inside shell 270 and extends from the combustion chamber 218 to the bottom head 276. Suitable openings are provided in head 276 for receiving the lower end portions of the heat exchange coils of the exhaust system.
  • Shell 270 is also provided with internally screw-threaded water inlet and outlet couplings 280 and 282 which are located in openings in the'shell and-are welded in place. These couplings will receive external pipe work to be connected to the interior of the "boiler" represent- ated by shell 270 and heads 274 and 276 for circulation of water around the combustion chamber and exhaust system.
  • a third, similar coupling 284 is provided adjacent the lower end of shell 270 and is fitted with a plug 286 for clean out purposes.
  • the inner casing construction as described above has a significant advantage in that the air cushion chamber section 226 and the exhaust chamber section 230 are assentially isolated from one another by a sealed boiler section 228. As a result, there is virtually no risk of leakage or exhaust gases from the muffler chamber 2023 or the exhaust chamber 210 to the air cushion chamber 204. Additionally, this form of construction has the advantage that the heater can be constructed as three sub-assemblies which can be assembled individually and then bolted together as described. The assembly is then fitted into the outer casing 224 and the space between the two casings is filled with fiberglass insulation.
  • FIG 13 illustrates the gas cushion sub-assembly of the heater, which is generally designated 288.
  • This assembly includes cushion chamber 214 itself and the valve means associated with the combustion chamber 218.
  • the valve means is essentially the same as that previously described with reference primarily to Figures 4 and 5 and will not therefore be described again in detail.
  • the valve means includes a valve plate 290 which is coupled to the gas cushion chamber 214 by a series of gas inlet tubes 292.
  • the tubes 292 communicate with the interior of the gas cushion chamber 214 and with gas inlet openings in plate 290. At its lower end, each tube is surrounded by a series of air openings in plate 290 which allow air from the air cushion chamber 204 to enter the combustion chamber.
  • a valve comprising a valve retainer plate 294 and a valve disc (not shown) all as previously described with reference to Figures 4 and 5.
  • a pressure sensing tube 296 also extends upwardly from plate 290 and is fitted with coupling 298 at its outer end. Tube 296 communicates at its lower end with an . opening in plate 290 which provides communication with the interior of the combustion chamber 218 when the gas cushion chamber sub-assembly is in place on the combustion chamber. Thus, by means of tube 296 a signal can be obtained as an indication of the pressure in the combustion chamber. This signal is used as an indication of whether or not combustion has been satisfactorily established in chamber 218.
  • valve plate 290 When the gas cushion chamber sub-assembly is fitted to the combustion chamber, valve plate 290 is disposed on top of the chamber and is held in place by a clamping ring 300 which extends around the gas inlet tubes 292 above plate 290. Ring 300 is formed with four equally spaced openings 302 which match both with corresponding openings 304 in plate 290 and with four externally screw- threated studs 306 which project upwardly from the top of combustion chamber 218.
  • sub-assembly 288 is mounted on the combustion chamber by fitting the valve plate 290 and the clamping right 300 over the studs 306 and fitting suitable nuts and washers to the studs.
  • gas cushion chamber 214 is specially designed to provide recessed areas 308 in its external surface.
  • the gas cushion chamber 214 is assembled from two substantially identical shell sections 310 and 312 which meet in a horizontal median plane of the chamber. Both sections are of oval shape in said plane and have side walls which are progressively shaped in moving away from said plane to define arcuate section troughs which form the recesses 308 referred to above.
  • each shell has the general appearance of an oval which has been inwardly constricted at both sides of a center section.
  • the upper shell 312 is formed around its lower margin with an outwardly stepped portion 312a which defines a recess receiving the upper marginal portion of the lower shell section 310.
  • the gas cushion chamber sub-assembly 288 has been designed so that its component parts can be assembled or stacked together generally in the positions in which they are shown in Figure 13 and passed through a furnace brazing oven for brazing of the parts to one another.
  • the valve disc retaining plates of the valve arrangement (as plates 294) are designed to be secured in place by brazing.
  • the design of the gas cushion chamber sub-assembly also has the advantage that it can be bolted onto the combustion chamber of the heater as a unit.
  • the design of the gas cushion chamber also allows ready access to the mounting studs 306 ( Figure 11) using a socket wrench as discussed previously.
  • gas is delivered to the gas cushion chamber 214 through a gas supply pipe 216 which extends through the wall of the air cushion chamber section 226 of the inner casing.
  • pipe 266 is fitted with a gas pressure regulator 314 which has a control port 316 for receiving an air pressure signal by which the regulator 314 is biassed to vary the gas pressure delivered to the gas cushion chamber 214 according to the air pressure in chamber 226.
  • This signal is provided by way of a pressure sensing tube 318 which extends from port 316 through the inner and outer casings 222 and 224 and which is secured in place by a suitable adhesive.
  • Regulator 314 is designed to control the pressure of the gas supplied to chamber 214 in accordance with the air pressure in air cushion chamber 204 so as to maintain a substantially constant/gas ratio. This has been found to be advantageous from the viewpoint of improving reliability of the heater.
  • the gas supply line Upstream of the gas pressure regulator 314, the gas supply line includes a solenoid operated gas valve for controlling delivery of gas to combustion chamber.
  • the valve is a conventional on/off valve and has not been shown in detail.
  • the fan unit 212 of the heater is shown in an exploded position in Figure 11.
  • the unit includes an electric motor 320 and a shrouded impeller enclosed within a housing indicated at 322 in Figure 11.
  • the housing includes a peripheral flange 324 which rests on the bottom face 236 of the recess 232 in the air cushion chamber section 226 when the fan unit is in its installed position.
  • a foam rubber gasket 326 is secured to flange 324 by adhesive for sealing with face 236.
  • the impeller casing 322 includes an upwardly extending, central air inlet 328 and a helical compression spring 330 extends around inlet 328 and is dimensioned to fit between the portion of the impeller casing around the inlet and the underside of the lid 238 of the inner casing.
  • flange 324 rests on the end face 236 in recess 232 and the lid 238 is bolted onto the top of the air cushion chamber section 226.
  • spring 230 is under slight compressive loading and serves to urge the impeller casing 322 against face 236.
  • FIG 14 is an exploded view of the impeller and housing.
  • Housing 322 made in two parts, comprising an upper housing part 322a and a lower housing part 322b. The two parts have flattened peripheral portions which cooperate to define flange 324.
  • Housing part 322a has the general shape of a shallow dome with a generally cylindrical upward extension as its center which defines air inlet 328.
  • the lower housing part 322b is generally dish- shaped and includes a recessed central region 332 of circular shape surrounded by an annular wall 334. Wall 334 is formed with a series of circular air outlet openings 336.
  • An impeller 338 is shown positioned between the two parts of the housing in Figure 14.
  • the impeller includes a disc-shaped main portion 340 surrounding a central boss 342 and having on its upper surface a plurality of arcuate shaped vanes 344 which radiate outwardly from boss 342.
  • Boss 342 has a central bore which receives the drive shaft of motor 320 (not shown) and the boss is clamped to the drive shaft by a set screw (not shown).
  • a thin aluminum shroud 346 of slightly disced circular shape is fitted to the tops of the vanes ' 344 so that open ended air passageways are defined between the vanes.
  • the vanes extend above the main portion of 340 of the impeller so that the passageways are open at their outer ends.
  • the vanes 344 are cut away to define an air inlet region around boss 342.
  • Shroud 346 is held in place by a number of relatively fine pins or studs which are formed on certain of the vanes which project through holes in the shroud and are peened over to hold the shroud in place.
  • the main portion 340 of the impeller is dimensioned to be accommodated within the recessed central portion 332 of lower housing part 322b so that the open outer ends of the air passageways defined between the vanes 344 discharge generally in the direction of the air outlet openings 336.
  • impeller shown in Figure 14 has been found to provide increased pressure output compared with a conventional impeller of comparable size.
  • a shrouded eight inch diameter impeller has been found eminently satisfactory for a heater of 100,000B.t.u. output.
  • a relatively high impeller output pressure has been found particularly desirable for ensuring reliable combustion cycle initiation where hot return water is present in the heat exchange chamber.
  • valve means specifically disclosed in this application, it is to be understood that the number of valves will vary according to the size of the apparatus. Seven valves have been found appropriate to a 100,000 B.t.u. unit, but a larger number would be required for a larger apparatus.
  • a pulse combustion apparatus of the form provided by the invention could be used as an engine for the recovery of mechanical or electrical energy.
  • the primary exhaust pipe could be omitted in some applications and heat exchange coil(s) connected directly to the combustion chamber (without a manifold).
  • the heat exchange pipes are also exhaust pipes whether or not a primary exhaust pipe (jet pipe) is present.
  • the primary exhaust pipe and/or the heat exchange coils may be internally coated with lead for corrosion protection and long life.
  • the lead coating may be applied by conventional techniques to a suitable thickness. A small percentage of tin or other material may be included with the lead for improved adhesion.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
EP79302521A 1978-11-15 1979-11-09 Appareil de combustion pulsatoire Expired EP0011457B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US960975 1978-11-15
US05/960,975 US4241723A (en) 1978-11-15 1978-11-15 Pulse combustion apparatus
US6702 1979-01-26
US06/006,702 US4241720A (en) 1979-01-26 1979-01-26 Pulse combustion apparatus

Publications (3)

Publication Number Publication Date
EP0011457A2 true EP0011457A2 (fr) 1980-05-28
EP0011457A3 EP0011457A3 (en) 1980-09-03
EP0011457B1 EP0011457B1 (fr) 1984-02-15

Family

ID=26675948

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79302521A Expired EP0011457B1 (fr) 1978-11-15 1979-11-09 Appareil de combustion pulsatoire

Country Status (9)

Country Link
EP (1) EP0011457B1 (fr)
AR (4) AR222053A1 (fr)
AU (3) AU536459B2 (fr)
BR (1) BR7907450A (fr)
CA (1) CA1119507A (fr)
DE (1) DE2966680D1 (fr)
HK (1) HK61687A (fr)
MX (2) MX149911A (fr)
SG (1) SG887G (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0069471A1 (fr) * 1981-06-19 1983-01-12 Condensing Boilers Limited Chaudiére
FR2512525A1 (fr) * 1981-09-10 1983-03-11 Collard A Trolart Sa G Appareil de rechauffage d'un liquide a serpentin
WO1984001018A1 (fr) * 1982-09-07 1984-03-15 Michael Cornelius Muntz Corps de chauffe a immersion dans un liquide
EP0180417A2 (fr) * 1980-12-22 1986-05-07 Arkansas Patents, Inc. Dispositif de combustion pulsatoire
US4651712A (en) * 1985-10-11 1987-03-24 Arkansas Patents, Inc. Pulsing combustion
EP0529988A1 (fr) * 1991-08-23 1993-03-03 Serchen Corporation Dispositif à combustion pulsatoire
GB2488207A (en) * 2011-02-15 2012-08-22 Gen Electric Pulse detonation combustor heat exchanger

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU594928B2 (en) * 1984-08-07 1990-03-22 Vulcan Australia Limited Instantaneous water heater
WO1986001282A1 (fr) * 1984-08-07 1986-02-27 Vulcan Australia Limited Chauffe-eau

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1993725A (en) * 1935-03-05 Gas fired boiler
FR1039035A (fr) * 1950-07-07 1953-10-05 Alfred Karcher Brûleur pour appareils de chauffage à gaz
US2701950A (en) * 1952-07-26 1955-02-15 Swingfire Bahamas Ltd Combustion device and check valve therefor
US2715390A (en) * 1950-07-18 1955-08-16 Tenney Resonant intermittent combustion heater and system
GB757852A (en) * 1953-08-14 1956-09-26 Motan Gmbh Improvements in or relating to heating apparatus
GB870444A (en) * 1956-07-11 1961-06-14 Lucas Industries Ltd Water heating apparatus
US3005485A (en) * 1958-05-07 1961-10-24 Lucas Industries Ltd Gaseous fuel combustion apparatus
US3267985A (en) * 1964-03-12 1966-08-23 John A Kitchen Pulse combustion apparatus
US3306352A (en) * 1965-02-10 1967-02-28 Curren John Leo Compact coiled tube heat exchanger
FR1535390A (fr) * 1966-09-01 1968-08-02 North American Aviation Inc Chambre de combustion résonnante pour le démarrage des turbines à gaz

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1993725A (en) * 1935-03-05 Gas fired boiler
FR1039035A (fr) * 1950-07-07 1953-10-05 Alfred Karcher Brûleur pour appareils de chauffage à gaz
US2715390A (en) * 1950-07-18 1955-08-16 Tenney Resonant intermittent combustion heater and system
US2701950A (en) * 1952-07-26 1955-02-15 Swingfire Bahamas Ltd Combustion device and check valve therefor
GB757852A (en) * 1953-08-14 1956-09-26 Motan Gmbh Improvements in or relating to heating apparatus
GB870444A (en) * 1956-07-11 1961-06-14 Lucas Industries Ltd Water heating apparatus
US3005485A (en) * 1958-05-07 1961-10-24 Lucas Industries Ltd Gaseous fuel combustion apparatus
US3267985A (en) * 1964-03-12 1966-08-23 John A Kitchen Pulse combustion apparatus
US3306352A (en) * 1965-02-10 1967-02-28 Curren John Leo Compact coiled tube heat exchanger
FR1535390A (fr) * 1966-09-01 1968-08-02 North American Aviation Inc Chambre de combustion résonnante pour le démarrage des turbines à gaz

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0180417A2 (fr) * 1980-12-22 1986-05-07 Arkansas Patents, Inc. Dispositif de combustion pulsatoire
US4637792A (en) * 1980-12-22 1987-01-20 Arkansas Patents, Inc. Pulsing combustion
EP0180417A3 (en) * 1980-12-22 1987-10-14 Arkansas Patents, Inc. A pulsing combustion device
EP0069471A1 (fr) * 1981-06-19 1983-01-12 Condensing Boilers Limited Chaudiére
FR2512525A1 (fr) * 1981-09-10 1983-03-11 Collard A Trolart Sa G Appareil de rechauffage d'un liquide a serpentin
WO1984001018A1 (fr) * 1982-09-07 1984-03-15 Michael Cornelius Muntz Corps de chauffe a immersion dans un liquide
US4651712A (en) * 1985-10-11 1987-03-24 Arkansas Patents, Inc. Pulsing combustion
EP0529988A1 (fr) * 1991-08-23 1993-03-03 Serchen Corporation Dispositif à combustion pulsatoire
GB2488207A (en) * 2011-02-15 2012-08-22 Gen Electric Pulse detonation combustor heat exchanger

Also Published As

Publication number Publication date
MX162226A (es) 1991-04-08
AR222053A1 (es) 1981-04-15
AU2667284A (en) 1984-07-26
AU560712B2 (en) 1987-04-16
AR231766A1 (es) 1985-02-28
AU5278779A (en) 1980-05-22
SG887G (en) 1989-09-01
AU536459B2 (en) 1984-05-10
AR231765A1 (es) 1985-02-28
EP0011457B1 (fr) 1984-02-15
DE2966680D1 (en) 1984-03-22
AU560711B2 (en) 1987-04-16
AU2667084A (en) 1984-07-26
MX149911A (es) 1984-02-08
BR7907450A (pt) 1980-08-05
EP0011457A3 (en) 1980-09-03
CA1119507A (fr) 1982-03-09
AR231764A1 (es) 1985-02-28
HK61687A (en) 1987-08-28

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