GB2165348A

GB2165348A - Forge hearth burner

Info

Publication number: GB2165348A
Application number: GB08524510A
Authority: GB
Inventors: Ian Hartley Clayphan; William Leonard James Higgs
Original assignee: HOT METAL EQUIPMENT Ltd
Current assignee: HOT METAL EQUIPMENT Ltd
Priority date: 1984-10-06
Filing date: 1985-10-04
Publication date: 1986-04-09
Also published as: GB8524510D0; GB2165348B; GB8425318D0

Abstract

In a forge hearth, interfitting refractory bricks locate a burner apparatus (22) in a central bore 32 of the centre brick (26). A flame defining member (24) has a mounting part (44) formed with longitudinal grooves (46) and designed to be an interference fit in a middle section (36) of the through bore (32). A head part (42) locates in a top bore section (38) spaced above a shoulder (40) and inwardly of the peripheral wall, whereby a continuous passage is provided for fuel entering from below the brick (26). The simple design facilitates ignition of the fuel above the burner apparatus and provides good flame retention. <IMAGE>

Description

SPECIFICATION Burner apparatus for a forge hearth This invention is concerned with a forge hearth and burner apparatus for the hearth, particularly forge hearths designed for handforging and other heat treatment of work pieces which operate with a gaseous fuel.

In premises such as school laboratories, craft workshops, and the like, forge hearths are used which operate on a gas fuel and air mixture. The mixture generally enters below the hearth and passes through a top opening where it has to be capable of being ignited, and ceramic chips are generally located on the hearth to provide for heat retention and distribution. Difficulties can be encountered with such types of forge hearths with regard to ease of ignition and flame retention.

It is an object of the present invention to provide an apparatus of an improved design capable of efficient ignition and flame retention.

According to the present invention there is provided burner apparatus for use with a forge hearth, the apparatus comprising a flame defining member and a support therefor, the support being adapted to locate in a forge hearth and having a passage communicating with a face of the support which is uppermost in use, and the passage being arranged to locate an inlet for gaseous fuel, the flame defining member being adapted to so locate in the passage that fuel can pass therethrough, the relative dimensions of the passage and the flame defining member being such as to enable ignition of the fuel and flame retention at the support face.Preferably the passage has one section receiving a mounting part of the flame defining member and a further section, which opens onto the support face, locating a head part of the flame defining member, means being provided to enable the fuel to pass through said one section of the passage, and the relative dimensions of the further section and the head part of the flame defining member being such as to enable the ignition and flame retention.

The through passage in the support may be defined as a bore with first, second and third sections thereof increasing respectively in diameter, the second and third sections being said one and said further sections respectively, whereby an annular shoulder is defined between each pair of adjacent sections. Preferably the second section increases steplessiy in diameter towards the support face and the mounting part of the flame defining member is of substantially circular cross-section with the diameter decreasing steplessly in a direction away from the head part, the relative dimensions being such that location of the flame defining member in the second section results in an interference fit, with the head part spaced from the shoulder defined between the second and third sections.Further, the diameter of the third section is greater than the diameter of the head part of the flame defining member whereby an annular space is defined therebetween.

Preferably the mounting part of the flame defining member has longitudinal grooves provided therein to allow passage of the gaseous fuel therethrough when the flame defining member is positioned within the passage.

Preferably also, the first section of the passage in the support is internally threaded whereby to receive a gas inlet tube.

The flame defining member may be formed of a ceramic material, and also the support may be formed of a ceramic material.

Advantageously the support tapers in crosssection from the upper face so as to be locatable within a complementary shaped aperture in a forge hearth.

The invention also provides a forge hearth including a burner apparatus as described in any of the preceding paragraphs. The hearth may be formed of a plurality of members defining a central aperture in which the burner apparatus is located, earth of the hearth members and the burner apparatus presenting interfitting faces, whereby location of the burner apparatus in the hearth prevents individual removal of the members.

An embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic plan view of a forge hearth incorporating a burner apparatus according to the invention; Figure 2 is a schematic elevation in crosssection through the burner apparatus; and Figure 3 is an underneath plan view of a flame defining member forming part of the burner apparatus.

Referring to the drawings, a forge hearth designed to be free-standing on any conventional support framework includes an arrangement of refractory bricks which are designed to be interfitting by means of angled connecting faces, i.e. a front brick 10, a back brick 12, side bricks 14, and a centre brick 16. The brick 16 defines a central aperture 18 of circular cross-section, with a diameter decreasing towards the lower face of the hearth. The back brick 12 is arranged to mount an ignition arrangement through an aperture 20 in a conventional manner.

A burner apparatus 22 is adapted to locate in the aperture 18 and is formed of a flame defining member 24 and a support 26 for the latter. The support 26 is of circular crosssection tapering from an upper face 28 to a lower face 30 whereby to be complementary in shape to the aperture defined by the brick 16. When the burner apparatus 22 is located in the aperture 18, the bricks 10 to 16 cannot be individually removed.

The support 26 is preferably formed of a ceramic material and defines a passage or bore 32 extending centrally between the upper and lower faces 28, 30. From the lower face 30 the bore defines a first section 34 of constant diameter, the section 34 being internally threaded to receive an inlet tube (not shown) for a gaseous fuel and air mixture. The section 34 opens into a second section 36 of increased diameter wherein the diameter increases steplessly and upwardly to a third section 38. The latter is of greater diameter than the section 36 whereby to define an annular shoulder 40, and also has a diameter which increases steplessly towards the upper face 28.

The flame defining member 24 is preferably formed of a ceramic material and has a head part 42 of circular cross-section but of a diameter less than the minimum diameter of the bore section 38 of the support 26. The member 24 further has a mounting part 44 extending from a lower face of the head part 42 and also having a circular cross-section decreasing in diameter in the direction away from the head part 42. The maximum diameter of the mounting part 44 is less than the diameter of the head part 42 and the relative dimensions of the mounting part 44 and the bore section 36 are such that, when the mounting part 44 is located in the section 36, an interference fit occurs, and the flame defining member 24 is retained in a position wherein the head part 42 is spaced above the shoulder 40 of the bore 32.Preferably cement is applied to the mounting part 44 before it is located in the bore section 36 so that the flame defining member 24 is fixed to the support 26.

A plurality of grooves 46 are formed longitudinally on the mounting part 44 of the flame defining member 24 whereby the outer periphery is effectively defined by radially extending ridges 48 which engage with the wall of the bore section 36 to form the interference fit. The grooves 46 thus provide communication between the lower part of the bore section 36 and the bore section 38, while the spacing of the head part 42 above the shoulder 40 provides a continuous passage for the gaseous fuel into an annular passage 50 defined between the periphery of the head part 42 and the wall of the bore section 38.

In use, the flame defining member 24 is fitted to the support 26 and the assembled burner is then located in the aperture 18 of the hearth. A fuel inlet is then connected to the support 26 and the gas and air mixture passes through the burner apparatus to flow upwardly through the annular passage 50 for ignition. The design of the apparatus has been found to facilitate ignition and provide for good flame retention. When ceramic chips are provided on the hearth to provide for heat retention and distribution, the chips will locate themselves in the annular passage 50, but this does not affect the performance of the burner which can perform satisfactorily with or without the ceramic chips. Thus a very effective but much simplified burner has been provided.

The shoulder 40 acts as a barrier preventing chips from falling down into the pipework and the passage 50 is so dimensioned as to be easy to clean out if necessary. Further the apparatus may be designed to have air pressure at the burner at all times when the apparatus is in use which ensures that dust and chipping are blown free, a build-up of gas is prevented, and a luminous flame is prevented.

Various modifications may be made without departing from the invention. For example the fuel inlet arrangement may differ from that described and shown and also the arrangement of grooves in the flame defining member may alter, provided the design of the annular passage opening onto the upper face is such as to ensure the desired ignition and flame retention performances.

Whilst endeavouring in the foregoing Specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to whether or not particular emphasis has been placed thereon.

Claims

1. Burner apparatus for use with a forge hearth, the apparatus comprising a flame defining member and a support therefor, the support being adapted to locate in a forge hearth and having a passage communicating with a face of the support which is uppermost in use, and the passage being arranged to locate an inlet for gaseous fuel, the flame defining member being adapted to so locate in the passage that fuel can pass therethrough, the relative dimensions of the passage and the flame defining member being such as to enable ignition of the fuel and flame retention at the support face.

2. Apparatus according to claim 1, wherein the passage has one section receiving a mounting part of the flame defining member and a further section, which opens onto the support face, locating a head part of the flame defining member, means being provided to enable the fuel to pass through said one section of the passage, and the relative dimensions of the further section and the head part of the flame defining member being such as to enable the ignition and flame retention.

3. Apparatus according to claim 2, wherein the passage is defined as a bore with first, second and third sections thereof increasing respectively in diameter, the second and third sections being said one and said further sections respectively, whereby an annular shoulder is defined between each pair of adjacent sections.

4. Apparatus according to claim 3, wherein the second section increases steplessly in diameter towards the support face and the mounting part of the flame defining member is of substantially circular cross-section with the diameter decreasing steplessly in a direction away from the head part, the relative dimensions being such that location of the flame defining member in the second section results in an interference fit, with the head part spaced from the shoulder defined between the second and third sections.

5. Apparatus according to claim 3 or 4, wherein the diameter of the third section is greater than the diameter of the head part of the flame defining member whereby an annular space is defined therebetween.

6. Apparatus according to any of claims 3 to 5, wherein the first section of the passage in the support is internally threaded whereby to receive a gas inlet tube.

7. Apparatus according to any of claims 2 to 6, wherein the mounting part of the flame defining member has longitudinal grooves provided therein to allow passage of the gaseous fuel therethrough when the flame defining member is positioned within the passage.

8. Apparatus according to any of the preceding claims, wherein the flame defining member is formed of a ceramic material.

9. Apparatus according to any of the preceding claims, wherein the support is formed of a ceramic material.

10. Appartus according to any of the preceding claims, wherein the support tapers in cross-section from the upper face so as to be locatable within a complementary shaped aperture in a forge hearth.

11. Burner apparatus for use with a forge hearth substantially as hereinbefore described with reference to the accompanying drawings.

12. A forge hearth including burner apparatus according to any of the preceding claims.

13. A forge hearth according to claim 12, comprising a plurality of members defining a central aperture in which the burner apparatus is located, each of the hearth members and the burner apparatus presenting interfitting faces, whereby location of the burner apparatus in the hearth prevents individual removal of the members.

14. A forge hearth substantially as hereinbefore described with reference to the accompanying drawings.

15. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.