US2975828A - Air heater - Google Patents

Description

March 21, 1961 A. H. ROBSON AIR HEATER Filed June 5, 1957 EXHAUST GAS FIG.2

IIVVENTOI? AUBREY H. ROBSON $4M (Kw ATTORNEY United States Pater AIR HEATER Aubrey H. Robson, Rock Island, 111., assignor to American Air Filter Company, Inc., Louisville, Ky., a corporation of Delaware Filed June 5, 1957, Ser. No. 663,795 3 Claims. (Cl. 15836.6)f

into the pot where it is vaporized and ignited by the heat from the burning oil, the combustion process being selfsustaining as long as additional oil is fed to the pot.

One conventional method of initially igniting oil in a pot burner is to insert a burning torch into the pot and hold the torch adjacent the surface of the oil until the oil is vaporized and ignited. -'Ihe torch may then be withdrawn since the heat from the ignited fuel vaporizes and ignites additional oil flowing to the pot. This torch method of ignition is objectionable because: the fuel tank is often used as a source for saturating the torch, this practice sometimes resulting in particlm being dis-lodged from the torch and ultimately clogging the fuel supply line; there is a certainamount of danger inherent in handling a flaming torch; and, if the fuel is cold, it may 7 take a relatively long time to ignite it. Thus, there have.

been a number of ignition arrangements devised, but

such arrangements are typically complicated and expensive in relation to the cost of the heater. 7

Therefore, it is the principal object of this invention to provide an ignition system for pot burners which is sim ple and inexpensive.

A further object is to provide an ignition system which may be operated to quickly and conveniently ignite the fuel in the burner.

In accordance with my invention, I mount an ignition chamber on the outer side of a circumferential wall of a conventional pot burner so that the interior of the chamber is in open communication with the interior of the burner. A spray nozzle mounted in the outer sidewall of the ignition chamber is arranged to discharge a spray of fuel particles into the pot when fuel is supplied under pressure to the nozzle. A fuel supply conduit interconnects the 'mlet of the nozzle to a fuel supply conduit and a manually operated fuel pump is interposed in the supply conduit between the fuel source and the nozzle so that the pump, when operated, will deliver fuel under spray producing pressure to the nozzle. A fuel igniter is mounted in a Wall of the chamber with the igniting element thereof positioned in igniting proximity to the path of spray discharge from the nozzle so that when the fuel igniter is connected to an electrical energy source, the igniting element will operate to ignite the fuel particles 1 being discharged into the burner by the nozzle.

ice

, centrically positioned in nesting relationship in an outer cup-shaped shell 5 of somewhat greater diameter and height, the circumferential side wall 5 of the shell forming with the pot wall 1 a vertical annular chamber 6 which is in communication with the outlet end of duct 4 by virtue of the open space 7 between pot floor 2 and the shell floor 8. Combustion air from the outlet of duct 4 flows radially outward to the annular chamber 6 and thence through the holes 3 into the pot to support combustion. e

A heat exchange chamber .9, in the form of a cup of larger diameter than the shell 5, is mounted in inverted position above the combustion chamber. It includes a circumferential side wall 9, a horizontal top wall 10, and an annular flange 11 extending inwardly from its lower rim to the upper rim of the pot, this annular flange providing a top closure for the annular chamber 6. An exhaust stack 12 is connected to the upper portion of the chamber for the purpose of conveying combustion gases to a disposal point. n A draft of combustion air is created at the inlet end of duct 4 by a centrifugal blower 13, and a draft of ven- The invention is illustrated in the accompanyingdrawing wherein:

Figure 1 is a partly broken elevational view of a heater having a pot burner and showing, in somewhat diagrammatic form, the fuel system and ignition arrangement;

Figure 2 is a horizontal section taken along the .line 2-2 of Figure 1.

Referring to the drawing, the combustion chamber intilation air is created by axial fan 14, the fan and blower both being driven by electric motor 15. The ventilation air flows around the heat exchange chamber in the direction of the arrows in Figure 1, the ventilation'air picking up heat from the exchanger as it flows around the outside surface thereof. To direct the air around the heatexchanger, and to insure that it will pass closely adjacent,

to the outside surface thereof, a casing 16 is provided,

the casing having an inlet opening to accommodate the axial fan, and a suitable outlet opening on the opposite side of the heat exchanger. 2 a

A supply of liquid fuel such as oil is contained in tank 17 which is interconnected by conduit 18 to afuel inlet opening adjacent the floor of pot 1. A conventional valve 19 for regulating the flow rate is provided in the conduit 18.

The ignition chamber 20 is a separate box-like compartment having an open inner-end mounted on the side wall 1 of the pot, the portion of the pot wall bounded thereby being cut-out so that the interior of the pot and the ignition chamber are in open communication. The ignition chamber protrudes outwardly through the wall 5 of the outer shell so that the outer end of the chamber is easily accessible for mounting the ignition system com: ponents. The edges of the opening in side wall 5 through which the chamber projects are preferably welded or otherwise secured to the intersecting walls of the ignition chamber to effect a seal which prevents the escape of combustion air from the annular chamber 6 to at-.

mosphere. v

The closed outer-end wall of the ignition chamber carries a spray nozzle 21 which projects through the wall with its outlet within the chamber and directed towards the interior of the pot so as to discharge a spray of relatively fine fuel particles or droplets when fuel is sup pliedunder pressure to its inlet,'which is outside the outere end wall and interconnected by conduit 22 to the supply conduit 18. e

A conventional priming-type hand pump 23 is interposed in conduit 22 to receive fuel, and force it under cludes a cup-shaped pot 1 having a vertical circumferential pressure to the nozzle when the pump plunger is manual ly operated. The inlet andoutlet valves within the pump are arranged so that they close to prevent the flow of fuel through the pump when the pump is not being operated.

5 second fuel line and adapted to be operated to supply fuel to said nozzle means under a spray producing pressure; a fuel igniter mounted in said outer portion of said chamber with its fuel igniting element disposed in the path of 'a portion only of said spray to provide vaporization and includes: a bottom wall sloping downwardly from said outer end wall toward said pot.

References Cited in the file of this patent UNITED STATES PATENTS Beckstrorn Sept. 24, 1946 Resek et a1. Mar. 30, 1948 Letvin Aug. 30, 1949 Carlson Oct. 25, 1949' Resek et al Nov. 9, 1954 Lennox Jan. 3, 1956

Images