US2973033A - Fluid burning heaters - Google Patents

Description

Feb. 28, 1961 Filed March 26, 195'? M. W. PATRICK FLUID BURNING HEATERS 2 Sheets-Sheet 1 INVENTOR 4%91601 M 6/9/01 ATTORNEYS Feb. 28, 1961 M. w. PATRICK 2,97

FLUID BURNING HEATERS Filed March 26, 195? 2 Sheets-Sheet 2 FUEL PUMP a2 as 9'- 5 summit GAP SPARK /GENERATOR f 7 m5 76 cbmausTnoN AIR FAN MOTOR 1/ I 8? w /fl6' CIRCULATING AIR FAN MOTOR E'|o= I L zfi- 65 F,7? :zi

AL INVENTOR 6 6 MqzmmW/ am/m ATTORNEYS FLUID BUG HEATERS Malcolm W. Patrick, Bedford Heights, Ohio, assignor to Hupp Corporation, Cleveland, Qhio, a corporation of Virginia Filed Mar. 26, 1957, Ser. No. 648,646

2 Claims. (Cl. 158-48) This invention relates to fluid fuel burning heaters and more particularly to such heaters suited for use in automotive vehicles and the like.

The heaters which are presently used in automotive vehicles are usually of the circulating hot water type in which a portion of the water from the engine cooling system is circulated through a heat exchanger. Before such a heater can function effectively, the engine must be thoroughly warmed. The warm-up time required for an engine increases as the weather becomes colder, and during extremely cold weather or short trips, the engine cooling system may never reach a temperature suflicient to heat the interior of the vehicle properly. Also, such heaters cannot be used to heat the interior of automotive vehicles when the vehicle is at rest and the engine is not running. Prior liquid fuel burning heaters used in automotive vehicles have had serious limitations which have prevented their Widespread adoption and use. Usually such heaters can be operated only at their maximum rating. Thus the occupants of the vehicle are subjected to wide temperature fluctuations whether the heaters are switched on and ofl manually or thermostatically.

An object of this invention is to provide a novel fluid fuel burning heater particularly suited for use in automotive vehicles and the like which provide a substantially instantaneous supply of heat to the occupants and includes means for regulating the output of the heater to meet widely varying requirements.

A further object of this invention is to provide fluid fuel burning heaters with a novel ignition apparatus which assures positive ignition of the fuel even under adverse weather conditions.

Another object of the invention is to provide improved electrical control systems for fluid fuel burning heaters which are operative to start the burner, to control heat output, and, to provide a safety control or shut-oft for the system in the event of failure or overheating of any of the components.

Still another object of this invention is to provide a novel flame holder assembly for fuel burners which provides a swirling mixture of fuel and air whereby the fuel is completely burned and little or no carbon is deposited on any of the elements of the combustion apparatus.

It is an additional object to provide novel burners which operate efliciently over a wide range of rates of fuel consumption to supply heat in an amount proportionate to the rate of fuel flow.

Other objects and advantages of the invention will appear as the description proceeds in connection with the accompanying drawings in which:

Figure 1 is a longitudinal sectional view of a typical embodiment of the burner and heat exchanger of the present invention;

Figure 2 is a transverse section taken on the line 2-2 of Figure 1;

Figure 3 is an enlarged elevation of the novel flame holder;

2,973,33 Patented Feb. 28, lfifll Figure 4 is a side view of the flame holder of Figure 3;

and

Figure 5 is a diagram of the electrical control circuit for the heater.

Referring to Figure 1 of the drawing, there is illustrated a fluid fuel burner and heater assembly comprising a hollow tubular body having an air inlet 12 at one end in which a conventional fitting 13 containing an air filter 14 is mounted. A blower or fan 15 is driven by a motor 16 positioned in the air inlet 12. Adjacent its outlet end the body 10 carries a flange 17 secured by bolts 18 to a mating flange 20 mounted on a heat exchanger assembly indicated generally by the numeral 22. A metallic O-ring 23 is clamped between the flange to prevent the escape of combustion products.

A flame holder assembly 24 extends transversely across the interior of body 10 and is secured to inner wall body 10 by means of brackets 25 and bolts 26. A combustible fluid fuel which may be gaseous but which is preferably a liquid such as gasoline, kerosene, or diesel oil is supplied to the upstream side of flame holder assembly 24 through a feed tube 27.. The rate of flow of fuel from tube 2'7 is controlled by any suitable needle valve indicated at 28 in fuel line 29. Mounted in the body 10 adjacent tube 2'7 is a preheater 30 which heats the flame holder assembly 24 and the fuel feed tube 27.

A spark plug 32 mounted in a boss 34 welded to the body It) has an elongated electrode 36 which extends to a position substantially adjacent the center of flame holder 24.

The heat exchanger 22 comprises a hollow tubular body 4-9, the interior of which forms an elongated combustion chamber 42. Mounted on the outer surface of the tubular body at are a plurality of parallel heat transfer fins 50. The fins are thin metal plates punched out in the center to form flanges 52 which are pressed onto the exterior of the body 49.

Mounted in communication with the outlet end of combustion chamber 42 is a header 54- which receives gases issuing from the combustion chamber. Surrounding the tubular body 40 adjacent the inlet end of the combustion chamber 42 is a second header 56. The headers are connected by radiator tubes 58 and 60 which are loosely fitted in aligned openings extending through the fins 50. By redirecting the flow of gases from the combustion chamber 42 back through the radiator tubes 58 and 69 additional heat is supplied to the fins thus making for more eflicient heat transfer.. Mounted on the outlet 62 of header 56 is a flue 64 which leads to any convenient point at the exterior of the vehicle.

Details of the flame holder 24 are illustrated in Figures 3 and 4 of the drawing. As illustrated, the flame holder sheet 65 is in the form of a flat plate. However, it may be slightly dished or in the form of a truncated cone or of other suitable configuration.

Disposed in the center of the main flame holder sheet 65 is an oval shaped opening 66. Mounted over the opening 66 on the upstream side by means of upper and lower tack welds 68 is a cover plate 70 of the same oval configuration as the opening 66. The cover plate 70 is made slightly larger than the opening 66 so as to overlap the opening by approximately ,4 inch and is spaced about .010 inch from the flame holder sheet 65 to provide an oval passageway '71 between the sheet 65 and cover 7d. Extending radially of the flame holder sheet 65 are a plurality of passageways or slots 72. The slots 72 extend through the sheet and each is inclined at an angle of about 30 to the axis of the sheet as shown in Figure 4 of the drawing. The flame holder assembly is mounted in the body it) to dispose the major-axis ofthe plate 70 in a vertical position. a

Figure 5, to which detailed reference will now be made,

illustrates diagrammatically the major electrically operated units of the heater system and an electrical control system for operating these components. The system of Figure 5 includes a main heater control switch 76 which is of the double pole single throw type, the usual vehicle ignition switch 78 and a three-position manual switch 80, the three switches being mounted on the dash panel or other convenient location to permit ready access by the operator. One pole 82 of the main switch 76 is connected to the heater fuel pump 84 through a circuit which includes a lead 86, a normally closed safety cut-out switch 88, a normally closed over-heat switch 90, and a normally closed combustion air fan failure switch 92 and a lead 94. A heater element 96 which controls the position of the switch 92 is supplied with current when the switches 76, 88 and 90 are closed.

A normally closed solenoid valve 98 mounted in the fuel inlet line 29 between the fuel pump 84 and the fuel delivery tube 27 is connected in parallel with the circuit for operating the fuel pump 84. The supply of current to a heater element 100 for the switch 88 and the fuel pro-heater 30 is controlled by a heat responsive switch 102 mounted in the flue 64. When the switch 102 is cold, the movable switch arm occupies the position shown. When the switch is hot, the arm is moved into engagement with the lower pole 103 connected to the main power lead 104 which is also connected to the ignition switch 78 and the main switch 76.

The pole 106 of the main switch 76 is connected by appropriate leads to the spark generator 108 which serves the spark plug 32, to the motor 16 which operates the combustion air fan and to the low speed Winding of a motor 112 which operates a second fan, not shown, which circulates air over the heat exchanger assembly 22. The high speed winding of the motor 112 is connected to the lower pole 114 of the switch $0.

Assuming that the vehicle is running, that the ignition switch 78 is closed, and that the switches 76 and 80 are open, all of the components of the heater system will be at rest and the solenoid valve 98 will be closed. The heater may be placed in operation by closing the main switch 76 and opening the valve 28. This action opens the solenoid 98 and energizes the fuel pump 84, energizes the spark generator 108 and starts the combustion air fan motor 16 and the circulating air fan motor 112. Since the switch 102 normally occupies the position shown, the fuel pro-heater 30 will also be energized. If ignition is effected in the burner in the normal manner as explained in detail below all the switch elements of the circuit continue to occupy their positions shown until the flue switch 102 is heated sufficiently to move switch contact into the dotted line position to de-energize the fuel pro-heater 30 and the heater element 100 of the switch 88. This action also shunts the main switch 76. Accordingly, if heat is no longer desired and the occupant opens the switch 76, the fuel pump 84 is de-energized, the solenoid valve 98 is closed while the combustion air fan motor and the circulating air fan motor continue to run to supply air to burn the residual fuel remaining in the flame holder assembly and to dissipate the residual heat in the heat exchanger. In a short time, the residual fuel is consumed, the stack switch 102 cools oh and moves to its full line position and the remaining components are de-energized.

In the event that ignition fails, the switch 102 will remain on its full line position and current will continue to flow through the heater element 100' of the safety cut off switch 88. After a pre-set time sufficient heat will be generated to open the switch 88 thus breaking the circuit through the solenoid valve 98 and the fuel pump 84.

If the combustion air fan motor should fail when the heater is in operation resulting in imperfect combustion, the heater element 96 of the switch 92 will no longer be cooled by the incoming combustion air and after a short interval will generate sufficient heat to open the switch 92 to thereby close the solenoid valve 98 and stop the fuel pump 84. A further safety feature is provided in the overheat switch 90, which is positioned near the heater in the path of the circulating air. If insufiicient air flows past the heat exchanger, the switch 90 will open to thereby close the solenoid valve 98 and stop the fuel pump 84. Accordingly, it will be apparent that safety controls are provided for protection of the system and the occupants in the event of failure or overheating of any of the components.

The three position manual switch is provided to permit operation of the air circulating fan 112 at high or low speed. When the switch occupies its central position as shown, the fan operates on low speed when the main switch 76 is closed. When high speed operation is desired, the operator moves the switch to close the contact M4 to energize the high speed winding of the motor 112. The switch 80 also permits the fan 112 to be operated to provide summer ventilation without energization of any of the remaining components in the system.

When the heater is placed in operation by closing the switch 76, a stream of preheated fuel is directed on the upper portion of plate 70. Since there is no orifice or nozzle at the outlet of the tube 27, the fuel is delivered initially in a solid stream to the surface of the plate 73. Air circulated through the body 10 by the combustion air fan 15 wipes the fuel from the plate 70. A portion of the fuel passes onto the downstream surface of the plate 70 and is ignited by the electrode 36 of the spark plug 32, the spark jumping the gap between electrode 36 and plate 70. The major portion of the incoming air passes through the radial slots 72, which cause the air to travel in a helical swirling path as it passes through the combustion chamber 42. The plate 70 over the opening 66 provides a sheltered Zone at the center of the swirling mixture which assures positive ignition. The swirling action of the mixture of fuel and air produces a central low pressure area into which a thoroughly comingled mixture of fuel and air is drawn. The resulting intimate premixing facilitates the initiation and maintenance of combustion under widely varying conditions.

The oval opening 66 and plate 70 are positioned vertically in order to assure a uniform wetting and distribution of fuel over the flame holder plate 65. Gravity tends to pull the fuel downwardly after it hits plate 70 while the air stream directed against the cover tends to spread the fuel both outwardly and downwardly. The two downward components will cause the fuel to move more rapidly in that direction. The oval is dimensioned and positioned vertically so that fuel is distributed substantially uniformly to the flame holder sheet in all directions, substantially the same amount of fuel leaving from the sides of the oval plate as from the ends. The inclined slots 72 provide proper aeration at all rates of fuel feed. At low rates of feed only the central area of the flame holder sheet 65 is wetted. The wetted area increases circumferentially in size as the fuel feed is increased, substantially all of flame holder sheet 65 being wetted at maximum fuel feed. At high fuel flow rates the center of the wetted area may tend to shift downwardly, leaving vapor along the top portion of the flame holder. At all rates of fuel feed the swirling motion of the mixture promotes smooth progressive flame propagation which assures quiet and complete combustion as the mixture proceeds along combustion chamber 42. Because of the continued progressive displacement of the mixture in the vortex, ignition is maintained and the possibility of explosive re-establishment of the flame after momentary interruption is eliminated.

The combustion products pass through header 54 into radiator tubes 58 and 60, then into the header 56 from which they pass to the atmosphere through flue 64. Heat of combustion is transferred through the walls 44) of combustion chamber 42 and through the radiators 58 and 60 into the fins 50. The violent swirling motion produced by the angularly cut slots breaks up the layer of stagnant air lying against the surface of the combustion chamber and thus efiects better heat transfer to the combustion chamber wall and the fins. A ventilating air stream blowing over the fins 50 transfers the heat into the desired space of an automotive vehicle or the like.

The heater of this invention has been described in connection with an automotive vehicle. However, it is adaptable to other applications. For example, it may be associated with other components for uses such as heating houses and the winterization of various equipment, and heating of water instead of air by virtue of a boiler type heat exchanger.

The invention may be embodied in other specific forms without departing from the spirit of essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

l. A fuel burner comprising means defining an elongated hollow tubular body having an inlet opening at one end and an outlet opening at the other end, means for delivering air to said inlet opening to pass through said body toward said outlet opening, a flame holder plate extending transversely across said body, said flame holder plate having a central opening and radially elongated slots which are inclined with respect to the axis of said body to direct air flowing through the slots in a swirling path downstream of the flame holder plate, a cover plate mounted on the upstream side of said flame holder plate and covering said central opening, means for supplying fuel to said burner immediately adjacent the central portion of the upstream side of said flame holder plate, and ignition means adjacent the central portion of the downstream side of said flame holder plate.

2. A fuel burner comprising means defining a hollow body having an inlet opening at one end and an outlet opening at the other end, means for delivering air to said inlet opening to pass through said body toward said Outlet opening, a substantially planar flame holder plate extending transversely across said body, said flame holder plate having a central opening and a plurality of radially extending passageways formed at an angle to the upstream surface of said plate, a cover plate mounted over the upstream side of said opening, the marginal edges of said cover plate being spaced slightly from the edges of said opening in said plate, means for supplying fuel to said burner immediately adjacent the upstream side of said cover plate and ignition means adjacent the central portion of the downstream side of the flame holder plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,542,294 Fogler June 16, 1925 1,676,501 Moors July 10, 1928 2,121,271 Szabo June 28, 1938 2,379,017 McCollum June 26, 1945 2,386,746 Hess Oct. 9, 1945 2,443,707 Korsgren June 22, 1948 2,489,716 McCollum Nov. 29, 1949 2,544,299 Damon Mar. 9, 1951 2,547,040 Perle Apr. 3, 1951 2,556,047 Stanley June 5, 1951 2,620,787 Zink Dec. 9, 1952 2,721,607 Damon Oct. 25, 1955

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