US1399638A - Furnace - Google Patents

Description

R. MARK FURNACE.

APPLICATION FILED, MAY 6. r920.

Patented Dem fl W21 4 $HEETSSHEET l- R. MARX.

FURNACE.

APPLlCATlON FILED MAY 6,1920.

1,399,638, Patentedl Dec. 6,, 1921.,

4 SHEETSSHEET 2.

R. MARX.

FURNACE.

APPLICATION FILED MAY 6, I920.

'JPatented Dec 6, 1921.

4 SHEETSSHEET 3.

R, MARX.

FURNACE. APPLICATION FILED MAY 6, 1920- Pa'tentm Deco 7 6,, 1921.,

4 SHEETSSHEET 4.

UNITED STATES RICHARD MARX, O-F PHILADELPHIA, PENNSYLVANIA.

FURNACE. 1

Specification of Letters Patent.

Patented Dec. 6., 1921.

Application filedMay 6, 1920. Serial No. 379,320.

To all whom it may concern:

Be it known that I, RICHARD MARX, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented Furnaces, of which the following is a specification. I

One object of this invention is to provide a furnace of the general type described and claimed in my application for U. S. Patent #328,442, filed October 4, 1919, whose construction shall besuch that a part of its floor within its oxygen free heating chamber may be kept relatlvely cool, inorder to permit-of the heat treatment of but a portion of an object such as a die cutter or some other tool placed on the furnace.

A further object of the invention is to provide a novel form of heating furnace which shall permit of the use of a bath of some liquid in permanent communication with its oxygen free chamber, either with a vlew to maintaining the liquid itself in a fused condition without subjecting it to the oxidizing action-of the air, or of making possible the transfer of articles from the interior of the furnace to the liquid Without subjecting them to material cooling or oxidation.

These objects and other advantageous ends I attain as hereinafter set forth, reference being had to the accompanying drawlugs, in which,

Figure 1 1s a side elevation of a furnace embodying my invention;

Fig. 2 1s a transverse section on the line 2-2, Fig; 1; i

Fig. 3 isa sectionon the line.3--3', Fig. 2;

Fig. li-is a horizontal section on the line an, Fig. 1;

Fig-,5 is a front elevation of a modification of my invention;

Fig, 6 is, a vertical section on the line 6--6,

5; 1 lg. 77 is, a side elevation of another form of the invention;

Fi 8. is a vertical section on the line 8--8, Fi a and 1g. '9 is a fragmentary vertical section on the line 9-9, Fig. 7.

Tn the above drawings 1 represents the metal inclosing casing of a muffle furnace which is usually supported on a set of legs 2 and has a refractory lining 3. In the interior of this structure is mounted a muffle consisting in the present instance of an elongated metal chamber 4 open only at the floor, sides, top and back of the furnace chamber and is permanently open through the front of the casing 1, although the combustion space 6 surrounding it is cut off from this front opening. Said space how- 'ever is provided at its top with suitable outlets 7 for the escape of products of combustion and is designed to be heated by some form of gaseous fuel delivered from two sets of burners 8 discharging into its lower portion from opposite sides.

These burners through pipes 9 and 10 are supplied with a mixture of air and gas from mains 11 and 12 and the proportions of these ingredients may be regulated by valves 13 and 14 connected between the mains and the pipe 10. Extending transversely below the level of the floor of the muffle immediately adjacent its open end is a burner in the form of a pipe 15 having a series of closely spaced relatively small openings formed along its topmost portion designed to supply a series of jets of fuel all in the same substantially vertical plane at or immediatelyadjacent the entrance to the muffle 41. The fuel for these jets is delivered through a pipe 16 supplied from the mains 11 and 12 and regulated as to its composition by a pair of valves 17 and 18. Upon being ignited the fuel escaping from th1s burner forms a continuous sheet or our tain of burning fuel which completely closes the opening to the muffle and prevents entrance ofair thereto as'well as extracts oxygenfrom its interior.v

The bottom of the muffle 4:, in the present instance immediately adjacent the front thereof, has an outlet opening 19 to which is connected a vertical conduit 20 whose lower end opens below the surface of a liquid such as oil within a "container 21 placedunder the furnace. A shelf 22 is fixed to the front of'the furnace casing so that its top surface is continuous with said muffle floor and serves to support articles burners 8 into the space 6', and oxygen is not only excluded but is removedfrom the interior of said muffle by the curtain of burning fuel indicated at w in Fig. 1, which is delivered across its open end from the burner pipe 15. After said latter burner has been in operation for a relatively short period only inert gases such as nitrogen and carbon dioxid remain within the mufi'le so that articles to be subjected to a heat treatment may be introduced through said curtain and raised to the desired temperature without being subjected to the objectionable posed to the atmosphere.

If it be desired to raise but a portion of any given object such as a die or cutter to a high temperature under the conditions above described, I may construct the furnace as shown in Figs. 7 to 9 inclusive, in which an airflue or passage 25 is provided under the metal floor or bottom of the muffle at some distance to the rear of the burner 15 for formlng the oxygen excluding curtain.

This conduit has an lnlet opening 26 preferably at its middle portion so that a current of cool air may enter at this point and divide so as to flow in opposite directions under the front portion of the bottom of the muffle and be discharged through outlets 27 in the side of the furnace casing. Obviously that portion of the floor. of the mufiie between the passage or conduit 25 and the burner pipe 15 is maintained by this air flow at a relatively low temperature, while the remainder of the mufile is raised to and kept at a uniform high temperature by the burning fuel delivered from the burners 8;-it being understood that the conduit .25,is preferably formed in refractory material under 'the floor of the muflie. Obviously a metal structure such as a die or tool resting on the front part of the mufilefloor would have that portion to the rear of the conduit 25 highly heated while its portion in.front of said conduit'would be kept relatively cool by conduction of its heat .pipe 15 extending across the floor of the mufiie so as to discharge a curtain of burn- -ing fuel across its second open. end as indi-' cated at 00 .With this construction material may be introduced to and removed from the muffle through either end thereof.

When a molten metal such as lead-isto to the cool part of the be used as a quenching material rather than oil, I may construct the furnace as shown in Figs. 5 and 6 in which form of my invention I provide a hollow metal casing 30 in the form of. abox having an inwardly extendin flange 31 around its open upper edges. This flange is designed to receive a casing in the form of a metal pot 32 suspended within the body of the box-like casing 30 and extended upwardly in the form of a cover or hood 33 having an opening in its forward side. As illustrated the structure 32-33 is a casting having a perforated conduit 34 extending through it in position to discharge aseous fuel in the form of a sheet upward y across the opening into its top 33. This passage or channel is connected to a source of fuel through a pipe 35 and a burner 36 is provided under the pot,32 within the casing 30 so that a body of lead 37 for example may be fused and maintained in a molten condition. Oxidation of this lead is prevented by the curtain 00 of burning fuel supplied from the conduit 34 across the opening-into the top'33 so that articles to be quenched may be introduced through said curtain and plunged I into or maintained in the lead in the pot 32 without being exposed to the oxygen in the atmosphere after having passed through said curtain. Obviously the lead may be maintained indefinitely in a melted condition without oxidation as long as the curtain :r'- is provided, it being understood that in this as well as in the other forms of my invention the air and gas supplying said curtain are -so proportioned that as the fuel is burned the oxygen is removed from the interior of the mulile or other heating chamber.

1, claim 1. The combination in a furnace of a inuflie having an opening; means for heating said muffle; means for maintaining a curtain of burning gaseous material across said opening; and means for causing a portion of the bottom of the muliie to be cooler than the remainder.

' 2. The combination in a furnace of a .muflle havingan air passage connected to the atmosphere and extending under a portion of its floor; means for heating. said mufiie; and means for preventing access of oxygen to the muflie consisting of a device for delivering a burning gaseous curtain across the opening of the mufiie.

3. The combination in a furnace of a casing having, a heating chamber; means for mounted in said chamber; means for permitting,circulation.of air under a portion ofthe floor of said mufiie to maintain the same at a relatively low temperature; and means for excluding oxygen from the muflie consisting of a burner tube positioned to supply a supplying fuel to said chamber; a mu-fiie the floor thereof which is maintained at a low temperature.

4. The combination in a furnace of a mufiie having an opening; means for maintaining a curtain of burning fuel across said opening to exclude oxygen from the muffle; and a liquid container communicating with the mufile.

5. The combination of a furnace having a muflie provided with an inlet opening and having an opening in its floor; means for supplying a curtain of burning fuel across said inlet opening; and a container cut oil from the atmosphere and communicating With said mufile through the opening in its floor.

6. The combination of a furnace having a mu'lile provided with a delivery opening and an inlet opening; a container having a body of liquid therein; a conduit leading from the delivery opening of the muffle to a point below the surface of the liquid in the container; and means for forming an air exeluding curtain across the inlet opening of the muflle.

7. The combination of a casing having an opening; a container for liquid communicating with said casing; and a burner for supplying a curtain opening.

8. The combination in a furnace of an inclosing casingra refractory lining forming a heating chamber; a muflie mounted in said chamber and having an opening to the atmosphere; means for providing a curtain of gaseous fuel across said opening consisting of a burner tube extending adjacent the opening; and means for forming an air conduit under the floor of the muffle to the rear of said opening.

of gaseous fuel across the RICHARD MARX.

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