US3733169A

US3733169A - Flame retention head assembly

Info

Publication number: US3733169A
Application number: US00227843A
Authority: US
Inventors: D Lefebvre
Original assignee: D Lefebvre
Current assignee: LEFEBVRE DENIS IN TRUST
Priority date: 1972-02-22
Filing date: 1972-02-22
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

Abstract

A flame retention head assembly for use in the air tube of a fuel burner having a fuel nozzle and ignition means for igniting the burner. The head assembly comprises a cylindrical ring positioned coaxially in the air tube and secured to the fuel nozzle. A spinner plate is secured inside the cylindrical ring adjacent the rear end of the ring and such plate is provided with a central opening facing the fuel nozzle. Vanes are formed in the spinner plate around the opening therein so as to impart a swinging motion to the air stream passing through the cylindrical ring thus causing a turbulence in the air stream to improve combustion of the flame produced by ignition of the fuel emitted by the nozzle. A cone-shaped flange is secured to the front part of the cylindrical ring and has openings therein for creating additional turbulence in the air stream at the outlet of the cylindrical ring to improve fuel combustion. Finally, a gap is provided between the cone-shaped flange and the air tube to permit flow of air at high velocity creating an overlapping air stream permitting to control the flame pattern.

Description

' United States Patent 1 Lefebvre [54] FLAME RETENTION HEAD ASSEMBLY [76] Inventor: Denis Lefebvre,l50-44ieme Avenue,

St. Eustache, Quebec, Canada [22] Filed: Feb. 22, 1972 [21] Appl. No.: 227,843

[5 6] References Cited UNITED STATES PATENTS 10/1968 Martin ..43l/350 9/1972 Dancyet al. ..43l/265 Primary Examiner-Carroll B. Dority, Jr.

A ttorney- Raymond A. Robic 57 ABSTRACT A flame retention head assembly for use in the air 11] 3,733,169 May 15, 1973 tube of a fuel burner having a fuel nozzle and ignition means for igniting the burner. The head assembly comprises a cylindrical ring positioned coaxially in the air tube and secured to the fuel n'ozzle. A spinner plate is secured inside the cylindrical ring adjacent the rear end of the ring and such plate is provided with a central opening facing the fuel nozzle. Vanes are formed in the spinner plate around the opening therein so as to impart a swinging motion to the air stream passing through the cylindrical ring thus causing a turbulence in the air stream to improve combustion of the flame produced by ignition of the fuel emitted by the nozzle. A cone-shaped flange is secured to the front part of the cylindrical ring and has openings therein for creating additional turbulence in the air stream at the outlet of the cylindrical ring to improve fuel combustion. Finally, a gap is provided between the cone-shaped flange and the air tube to permit flow of air at high velocity creating an overlapping air stream permitting to control the flame pat- Y tern.

5 Claims, 3 Drawing Figures PATENTEDHAYI Si n 1 FLAME RETENTION HEAD ASSEMBLY This invention relates to a flame retention head assembly for use in the air tube of a fuel burner using oil or gas.

With flame retention burners, the fuel spray originating from the nozzle of the burner maybe confined in a predetermined pattern and thus eliminate the need for a combustion chamber. The elimination of the combustion chamber increases the heat transfer of the burner and thus improves the burner output. In addition, flame retention head assemblies improve the flame stability and thus eliminate the well-known pulsation problem commonly known in other types of bumers.

The known flame retention burners use a spinner plate to impart a swirling motion to the air exiting from the air tube to cause a turbulence in the air stream at the outlet of the air tube to produce a more rapid mixing of the fuel spray with the combustion air so that a proper air-fuel ratio for combustion is obtained at the outlet of the air tube.

According to the present invention, a greater amount of turbulence is produced by placing the spinner plate within a cylindrical ring adjacent the rear end thereof. In addition, a cone-shaped flange is provided in front of the cylindrical ring and such flange is provided with openings therein which cause an additional turbulence in the air stream at the outlet of the air tube. Furthermore, a predetermined gap is provided between the cone-shaped flange and the air tube so as to permit a flow of air at high velocity, thus creating an overlapping air stream for controlling the flame pattern.

The invention will now be disclosed with reference to a preferred embodiment thereof and to the accompanying drawings in which:

FIG. 1 illustrates a perspective view of a flame retention head assembly in accordance with the invention;

FIG. 2 illustrates a section vie through the air tube illustrating a side-view of the head assembly; and

FIG. 3 illustrates another type of cone-shaped flange which may be used with the head assembly in accordance with the invention.

Referring to FIGS. 1 and 2, there is shown a flame retention head assembly placed within the air tube 12 of a fuel burner having a fuel nozzle 14 and a pair of electrodes 16 for ignition of the burner.

The head assembly comprises acylindrical ring 18 attached to the nozzle 14by means of three metal strips 20 secured to a bracket 22 which is tightened around the nozzle. A spinner plate 24 is secured within cylindrical ring 18 adjacent to the rear end thereof. The spinner plate 24 has an opening therein facing the nozzle 14 and is provided with a plurality of vanes 26 bent outwardly from the spinner surface toward the outlet of the tube. The vanes are provided for imparting a swirling motion to the air exiting from cylindrical ring which thus acts as a primary blast tube, the air tube 12 acting as a secondary blast tube. This causes a turbulence in the air stream atthe outlet of the cylindrical ring, as illustrated by the arrows, to improve the combustion produced by the ignition of the fuel emitted by the nozzle. The air turbulence is increased by the fact that it is confined by the cylindrical ring 18 and redirected towards the centerof combustion when it hits the cylindrical ring.

A cone-shaped flange 28 is welded or otherwise secured to the front end of the cylindrical ring 18 and is provided with legs 30 spaced around the periphery of the flange for centering the head assembly within the air tube 12 thus providing an even gap between the flange 28 and the air tube 12 for the circulation of air at high velocity between the flange and the air tube. The cone-shaped flange is provided with openings 32 which are sloped in such a way as to provide an additional swirling motion of the air exiting from the cylindrical ring. Indeed, the air flowing between the cylindrical ring 18 and the air tube 12 passes through the openings 32 in the flange and creates a further swirling motion of the air exiting from the cylindrical ring thus causing an additional turbulence in the air stream at the outlet of the cylindrical ring to improve combustion.

The main characteristic of the retention head assembly in accordance with the invention is that it provides a high speed flame due to its proper air fuel mixture. Such mixture is provided by four different air supplies as follows:

I. a first air supply from the center hole in the spinner .plate 24 for providing the primary ignition mixture,

2. a second air supply through the blades of the spinner plate causing a high air turbulence at the output of the cylindrical ring 18 acting as a primary blast tube,

3. a third air supply in the form of an air jet stream feeding the flame through the holes 32 in the flange 28 attached to the cylindrical ring 18, and

4. a fourth air supply through the gap between the flange 28 and the air tube 12 for controlling the flame pattern.

The presence of the spinner plate 24 reduces the velocity of the air flowing through the center of the air tube 12 and thus the portion of the air blast which flows between the air tube 12' and the flange 28 is at a higher velocity. A proper dimensioning of the flange 28 which partly blocks this high velocity flow will thus permit to control the flame pattern. A larger space between the flange 28 and the air tube 12 will provide a long and narrow flame pattern whereas, if the space between the flange 28 and the air tube 12 is reduced, it will produce a shorter and wider flame pattern.

Although the invention has been disclosed with reference to a preferred embodiment thereof, it is to be understood that various modifications may be made to the embodiment disclosed without departing from the scope of the invention. For example, a flange 28 having series of holes 32' such as illustrated in FIG. 3 may be used. The function of the holes 32' is the same as the apertures 32 in FIGS. 1 and 2. In addition, proper dimensioning of the air tube 12,0f the cylindrical ring 18, of the cone-shaped flange 28 and of the holes 32 will create predetermined retentions on the flame.

It has been found in practice that, with the retention head assembly in accordance with the invention, it is possible to tire against a positive or negative over firing pressure thus compensating for poor draft condition.

Various applications such as domestic, commercial and industrial are possible. It has been found in practice that the retention head assembly, in accordance with the invention, permits a 40 percent higher fuel input with comparable outside diameter blast tube. Test results have also revealed a high efficiency flame of an average temperature exceeding 2,700F with higher combustion thus lowering pollution.

The retention head assembly in accordance with the invention is also easy to assemble and disassemble, thus facilitating maintenance.

I claim:

1. A flame retention head assembly for use in the air tube of a fuel burner having a fuel nozzle and ignition means comprising:

a. a cylindrical ring positioned coaxially in said air tube and secured to said fuel nozzle;

b. a spinner plate secured inside said cylindrical ring adjacent the rear end of said cylindrical ring and in front of said fuel nozzle, said spinner plate having an opening facing said fuel nozzle;

c. vanes formed in said spinner plate around said opening so as to impart a swirling motion to the air exiting from the cylindrical ring thus causing a turbulence in the air stream at the outlet of the cylindrical ring to improve combustion produced by ignition of the fuel emitted by the noule; and

d. a cone-shaped flange secured to the front part of said cylindrical ring and spaced from said air tube, said cone-shaped flange having openings therein arranged to cause additional turbulence in the air stream at the outlet of the cylindrical ring.

2. A flame retention head assembly as defined in claim 1, further comprising a series of arms secured to the edge of said cone-shaped flange for evenly spacing said flange from said air tube so as to permit a flow of high velocity air between the flange and the air tube to control the flame pattern.

3. A flame retention head assembly as defined in claim 1, further comprising a clamp secured to said nozzle and metal strips interconnecting said clamp to said cylindrical ring for securing said cylindrical ring to said nozzle.

4. A flame retention head assembly as defined in claim 1, wherein said vanes are bent outwardly of the spinner plate surface toward the outlet of the air tube.

5. A flame retention head assembly as defined in claim 1, wherein said ignition means comprises a pair of electrodes converging towards the end of said nozzle for igniting the fuel spray exiting from the nozzle.

Claims

1. A flame retention head assembly for use in the air tube of a fuel burner having a fuel nozzle and ignition means comprising: a. a cylindrical ring positioned coaxially in said air tube and secured to said fuel nozzle; b. a spinner plate secured inside said cylindrical ring adjacent the rear end of said cylindrical ring and in front of said fuel nozzle, said spinner plate having an opening facing said fuel nozzle; c. vanes formed in said spinner plate around said opening so as to impart a swirling motion to the air exiting from the cylindrical ring thus causing a turbulence in the air stream at the outlet of the cylindrical ring to improve combustion produced by ignition of the fuel emitted by the nozzle; and d. a cone-shaped flange secured to the front part of said cylindrical ring and spaced from said air tube, said coneshaped flange having openings therein arranged to cause additional turbulence in the air stream at the outlet of the cylindrical ring.