US3670993A

US3670993A - Compact high capacity burner for hot air balloons

Info

Publication number: US3670993A
Application number: US79784A
Authority: US
Inventors: Byron L Kay; Walter H Thurn Jr
Original assignee: United States Department of the Air Force
Current assignee: United States Department of the Air Force
Priority date: 1970-10-12
Filing date: 1970-10-12
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20

Abstract

A burner for a hot air balloon having a conically shaped preheat coil supported by and spaced from a substantially conical shaped flame deflector. A manifold, with a plurality of radially positioned holes which direct the flame toward the flame deflector, is connected to the preheat coil so that fuel is supplied to the manifold through the preheat coil. Air is supplied through holes in the manifold support. Igniters, operated by the pressure of the fuel supplied to the preheat coil, direct a starting flame into the space between the flame deflector and the preheat coil.

Description

United States Patent Kay et al.

[ 1 June 20, 1972 I54] COMPACT HIGH CAPACITY BURNER FOR HOT AIR BALLOONS [72] Inventors: Byron L. Kay; Walter H. Thurn, Jr., both of Akron, Ohio [73] Assignee: The United States of America as represented by the Secretary of the Air Force [22] Filed: Oct. 12, 1970 [21] Appl.No.: 79,784

s2 u.s.c| ..244/32,431/24s [51] rm.c| ..B64bl/62 5s FieldofSearch.... ..244/30-33,24,

[56] References Cited UNITED STATES PATENTS 3,508,725 4/1970 Nebiker ..244/32 2,983,312 5/1961 Finleyetal, ..43l/248 1,755,602 4/1930 Jacobson ..43l/248 Primary Iiraminer-Andrew H. Farrell AuorneyHarry A. Herbert, Jr. and Richard J. Killoren 57 ABSTRACT A burner for a hot air balloon having a conically shaped preheat coil supported by and spaced from a substantially conical shaped flame deflector. A manifold, with a plurality of radially positioned holes which direct the flame toward the flame deflector, is connected to the preheat coil so that fuel is supplied to the manifold through the preheat coil. Air is supplied through holes in the manifold support. lgniters, operated by the pressure of the fuel supplied to the preheat coil, direct a starting flame into the space between the flame deflector and the preheat coil.

2 Claims, 7 Drawing Figures PATEHTEnJum I972 3. 670,993

SHEET 10F 2 INVENTORS COMPACT HIGH CAPACITY BURNER FOR HOT AIR BALIJOONS BACKGROUND OF THE INVENTION Hot air balloon burners currently in use are used primarily with sport balloons and are comparatively heavy and bulky. These have a sheet metal cylinder approximately inches long and about 7 inches in diameter with a fuel preheat coil wrapped around the top end of the cylinder. The burner tips in these burners normally have a single fuel jet opening and are mounted below the cylinder.

These burners are satisfactory for sport ballooning wherein weight and bulkiness are not problems and only low fuel consumption rates are required. In balloon systems used in the recovery of ejected pilots, that will provide discretionary descent capability, higher fuel consumption rates are required. If burners of the conventional design were used with these higher consumption rates, the top of the balloon would be burned, due to the jet-effect produced at the higher fuel consumption rates.

Also burners used in such a system must be lightweight and compact so as to meet the limited space requirement of the parachute-balloon pack carried by the pilot.

BRIEF SUMMARY OF THE INVENTION According to this invention a compact lightweight burner, weighing less than 3 pounds, is provided which has a capacity of about 3,000,000 BTU per hour. The burner has a manifold that directs the fuel radially where it mixes with air and burns. A fuel preheat coil is shaped in a conical configuration and is secured to a conical shaped flame deflector by means of spaced supports. The burner is ignited by a pair of fuel pressure initiated igniters.

IN THE DRAWING FIG. 1 is a top view of a hot air balloon burner according to the invention.

FIG. 2 is a view partially in section of the device of FIG. 1, along the line 2-2.

FIG. 3 is a view partially in section of the device of FIG. 1,

' along the line 3-3.

DETAILED DESCRIPTION OF THE INVENTION With reference to FIG. 1 of the drawing, a burner 10 has a burner manifold 12 shown in greater detail in FIG. 4. The manifold 12 is supported on a manifold support 14 which is secured to substantially conical shaped flame deflector 16, showing greater detail in FIG. 6, by any well known means such as welding. Fuel from a fuel supply, not shown, is fed to the burner manifold 12 through fuel input line 17, a swivel fuel inlet fitting 18, and then through a fuel preheat coil 19, which may be a copper tubing which is wound in a substantially conical configuration and which is connected to manifold 12. The coil is supported on the flame deflector in close substantially parallel spaced relation 16 by means of a plurality of spacer supports 21. The spacers can be secured to the coil and flame deflector by any well known means such as brazing.

Fuel is supplied to the burning region, between coil 19 and the flame deflector 16, through a plurality of small holes 25 in the burner manifold 12. In one device built, with butane being the fuel used, the manifold burner has 72 equally spaced holes of 0.026 inch diameter. Another burner using propane as the fuel had 62 equally s aced holes 0.028 inch in diameter.

ed by a pair of igniters 28 secured to the The burner IS lgm flame deflector 16. The igniters used are PIC- percussion igniters from Hi Shear Corp. Other percussion igniters than those described could be used. The igniters are connected to the swivel inlet fitting 18 by

tubes

30 and 31, and are operated by the pressure of the fuel supplied to chamber 36 in fitting 18 shown in FIG. 5. The flame deflector 16 has a plurality of holes, not shown, to mate with the igniter to admit the flame from the igniters to the space between coil 19 and flame deflector 16. Flame spreaders 20 having holes 22, are positioned over the holes in flame deflector 16. In the device built, a pressure diaphragm 34 was located between the annular chamber 36 in swivel fitting 18 and the input of preheat tube 19 to provide a delay to give the igniters time to operate before fuel is supplied to manifold 12. O-ring seals 38 are provided on each side of the chamber 36.

The burner is attached to the balloon by means of a plurality of pivotable support arms 40 which are secured to brackets 42. When the heater is mounted in the balloon, the arms 40 are secured to suspension lines 47 which are connected to the balloon. The arms 40 hold the suspension lines away from the hottest part of the flame from the burner 10.

The inlet of the balloon is suspended above the vent opening of a parachute, as shown in FIG. 7, with the burner being positioned above the vent opening in the balloon inlet.

In the operation of the device. when the fuel is turned on it passes through fuel line 17 into fitting 18. The almost immediate build-up of pressure in the chamber 36 operates the firing pin in the igniters 28 to provide a starting flame in the region between coil 19 and frame deflector 16. The diaphragm 34 is designed to break shortly after the igniters are operated to supply fuel through tube 19 into manifold 12 and then through holes 25 which is mixed with air supplied through openings 46 in the burner manifold support 14. The flame deflector '16 directs the flarne through coil 19 to vaporize the fuel at a rate sufficient to sustain high burn heating rates and also to supply hot air to the balloon.

There is thus provided a lightweight compact hot air balloon burner which is capable of providing the high heating rates needed in recovery systems for ejected pilots.

We claim:

1. A heater for hot air balloon comprising: a heater manifold; a fuel input line; a fuel preheat coil, wound in a substantially conical configuration, positioned adjacent said manifold and having one end connected to said manifold for supplying fuel thereto; means, including a swivel fuel inlet fitting connected to said fuel input line, for supplying fuel to the other end of said preheat coil; said swivel fuel inlet fitting having an annular internal chamber; means for directing a flow of fuel radially from said manifold; means, responsive to the fuel pressure within said annular chamber, for igniting said fuel; a breakable pressure diaphragm positioned in said swivel fitting between the annular chamber and the input to the preheat coil, whereby the fuel is supplied to the manifold after the igniters are operated; means, including a substantially conical shaped heat deflector, supported in close substantially parallel spaced relation to the preheat coil, for directing the hot gas from the burning fuel through the preheat coil whereby the fuel is preheated and vaporized and a plurality of support rods pivotably connected to the upper edge of the flame deflector, adapted to be connected to support lines of a hot air balloon.

2. The heater for a hot air balloon as recited in claim 1 in combination with a parachute having a vent opening of predetermined size in the top thereof; a hot air balloon suspended above the parachute with its inlet suspended above the vent opening of the parachute; means including said plurality of support rods for suspending the heater within the balloon a predetermined distance above the vent opening.

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