US2531344A

US2531344A - Air feeding and cooled furnace front structure

Info

Publication number: US2531344A
Application number: US784233A
Authority: US
Inventors: Thomas H Polad
Original assignee: RUDY FURNACE Co
Current assignee: RUDY FURNACE Co
Priority date: 1947-11-05
Filing date: 1947-11-05
Publication date: 1950-11-21
Anticipated expiration: 1967-11-21

Description

"r. H. POLAD 2,531,344

AIR FEEDING AND COOLED FURNACE FRONT STRUCTURE Nov. 21, 1950 Tho/i205 Po/ad Filed Nov. 5, 1947 I N VEN TOR.

A TTORNEY.

Patented Nov. 21, 1950 UNITED STATES AER FEET-ENG Ah? D COEZLEE) FURNACE FRONT STRUCTURE Thomas H. Polad, Dowa giac, Mich, assignor to Rudy Furnace Company, Dowagiac, Mich.

Application NovemberS, 1947, Serial No. '1 84J233 (Cl. lid- 189) 6 Qlaims. 1

This invention relates to improvements in furnace structure. 7

The principal objects of this invention are:

First, to provide means for cooling the door and frontplate of-a hot air furnace.

Second, to provide a furnace having air ducts therein for the admission of cooling air through the door and pouch extension to the top of the combustion chamber. 7 Third, to reduce the temperature of the door, front plate and pouch extension of a hot air :furnace to render the use of steel plates for the fur nace practical.

Other objects and advantages relating to details and economies of the invention will be apparent from the following description and claims.

The drawings, of which there is one sheet, illustrate a preferred form of my furnace structure.

Fig. 1 is afragmentary front elevational view of a hot air furnace embodying my invention.

Fig. 2 is a fragmentary vertical cross sectional view along the line 22 in Fig. 1.

Most hotair furnaces are constructed with an inner combustion chamber and an outer casin which is spaced from the combustion chamber'to provide for the passage of air to be heated around the combustion chamber. The casing is provided with a front plate defining charging door and ash door openings and the combustion chamher is provided with an extension sometimes called a pouch extension which is sealed to the front platearound the ash and charging doors to prevent the products of combustion from mixing with the air being heated. Since the front plate is open to the interior of the combustion h chamber along the pouch extension, it is subject to the intense heat of the fire in the combustion chamber and in the past has been made 10f cast iron due to the low eoefficient of expansion of iron and its resistance to heat. I g

It is my invention to provide a chambered charging door through which secondary air is admitted from outside the furnace casing and directed upwardly through the door and into the front of the pouch extension toward the top or dome of the combustion chamber. Air thus admitted to the furnace functions to cool the charging door and the front plate and also to act as secondary air for combustion in the top of the combustion chamber. I have found that the temperature of a furnace door andfront plate :may be reduced between 2'50 and 300 degrees under normal operation of the .furnace and the :combustion within the furnace .irnpr1oved means-of :my iair directing passages. The reduced Zthtd 6d temperature of the furnace door and front plate renders it practical to make the front plate of sheet steel rather than cast iron by reducing the tendency of the steel to buckle and deteriorate under high temperature,

The furnace illustrated in the drawings coinprises a casing 5 having a conventional head 2 and enclosing a fire pot or combustion chamber 3. The casing is provided with a front plate of sheet steel having an upper panel ii and lower panel 5 joined by a band 6. The edges of the front plate panels are connected to the sides of the casing by sealing strips 1.

The upper panel 4 defines a charging opening 8 closed by my charging door 9 and the lower panel 5 defines an ash opening closed by the ash door H]. The opening 8 in the top panel opens into the pouch extension ll of the combustion chem.- ber, the front wall of which is welded to the up.- per panel 4 as at l2, Adjacent to the top of the opening 8 I provide a pouch shield !3 which ex.- tends between the sides of the pouch extension and slopes upwardly .and inwardly to within the combustion chamber. It will be noted that the rent edge of the pouch shield is spaced slightly downwardly and inwardly from the upper edge of the opening 8 to provide a passage or flue it into the pouch extension. A familiar type of smoke curtain I5 is provided on the underside of the pouch shield.

I The charging door .9 for Closing the opening it consists of an outer panel 16 having rearwardly turned flanges ll arran ed t seat agains the op panel .4 around th op n ng 8- Th outer panel 1'5 is prov ed with a pa r of sl v s r spacer mem ers 1.8 which are w lded ther to and project toward th interi r of the fu na e and serve to support the center of he inne panel ill in spaced relationship with the outer panel The sides of the inner panel are flanged forward-1y as at 20 and welded to the side flanges of the outer panel l8. The inner panel is arranged to lie substantially in the same plane as the upper panel 4 of the casing when the charging dQOl is closed. The upper edge of the inner panel is spaced downwardly below the upper edge of the opening 8 to provide an opening or flue 2i regisr ig h th flue M a th trou edge of the pouch shield.

T e lower fla e l o the uter do r pa el d fines 1 s ri of ape tu es :22 arran d to admit outside a to t e ch mber 2. 5 formed between the inner outer pane s o the cha ing doorfllhe panel it being subieeted to the heat oi the hrs in the combustion chamber wil heat the air in the chamber 23 causing it to rise and be directed through the flues I4 and 2| to the pouch extension from where it will pass through the pouch extension to the top of the combustion chamber.

The flow of secondary air as just described will cool both panels of the charging door and in passing through the pouch extension will cool the top panel 4 of the furnace front and the front of the pouch extension so that these members will not be heated to the high temperature of the combustion chamber. The secondary air will mix with the products of combustion in the top of the combustion chamber to assure complete combustion and in so doing will prevent the temperature of the top wall of the combustion chamber from rising above a desirable level.

I have thus described a highly practical commercial embodiment of my furnace and have not attempted to illustrate other possible forms or arrangements of my structure as it is felt that such modifications as may appear practical or desirable in certain instances may be made without further description.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In combination with a hot air furnace having a steel front plate and a combustion chamber closed at the top by a dome and joined to said front plate by a pouch extension, said pouch extension including a top wall extending generally in an upward direction from said front plate toward the dome of the combustion chamber, said front plate defining a charging opening, a pouch shield positioned in said pouch extension and sloping upwardly and inwardly from adjacent the upper edge of said opening and defining a flue o ening into said pouch extension, said pouch shield being spaced from the pouch top wall to provide a passageway extending generally upwardly from said flue opening toward the dome of the combustion chamber to direct relatively cool air entering said flue opening to ards t e dome of the combustion chamber, a cha ging door for closing said chargins. opening, said door having spaced inner and o t r panels, the outer panel being rearwardly flanged to en age t e front surface of said front panel around said charging opening and defining a s ries of a ertures through the lower flange thereof opening to the space between said door panels, said inner panel having side flan es welded to the side flanges of said outer panel and terminating in spaced relationship with the u per edge of said charging opening when in closed position to define a second flue opening opposite said first flue.

2. In combination with a hot air furnace having a front plate and a combustion chamber closed at the top by a dome and joined to said front plate by a pouch extension, said pouch extension including a top wall extending generally in an upward direction from said front plate toward the dome of the combustion chamber, said front plate defining a charging opening, a pouch shield positioned in said pouch'extension and sloping upwardly and inwardly from the upper edge of said opening and defining a flue opening to said pouch extension, said pouch shield being spaced from the pouch top wall to provide a passageway extending generally upwardly from said flue opening toward the dome of the combustion chamber to direct relatively cool air entering said flue opening towards the dome of the combustion chamber, a charging door for closing said charging opening, said door having spaced inner and outer panels, the outer panel being rearwardly flanged to engage the front surface of said front panel around said charging opening and defining an aperture through the lower flange thereof opening to the space between said door panels, said inner panel terminating in spaced relationship with the upper edge of said charging opening when in closed position to define a second flue opening opposite said first flue.

3. In combination with a hot air furnace having a front plate and a combustion chamber closed at the top by a dome and joined to said front plate by a pouch extension, said pouch extension including a top wall extending generally in an upward direction from said front plate toward the dome of the combustion chamber, said front plate defining a charging opening, a pouch shield positioned in said pouch extension and sloping upwardly and inwardly from the upper edge of said opening and defining a flue along the front edge thereof, said pouch shield being spaced from the pouch top wall to provide a passageway extending generally upwardly from said flue opening toward the dome of the combustion chamber to direct relatively cool air entering said flue opening towards the dome of the combustion chamber, a charging door for closing said charging opening, said door having spaced inner and outer panels, said outer panel being rearwardly flanged to engage the front surface of said front panel around said charging opening and defining a passageway through the lower flange thereof opening from the outside of said door to the space between said door panels, said inner panel defining a second flue along the upper edge of said door opening opposite said first flue.

4. In combination with a hot air furnace having a front plate defining a charging opening and a combustion chamber closed at the top by a dome and joined to said front plate by a pouch extension, said pouch extension including a top wall extending generally in an upward direction from said front plate toward the dome of the combustion chamber, a pouch shield having its front edge spaced from the upper edge of said charging opening, said pouch shield being spaced from the pouch top wall to provide a passageway extending generally upwardly from said flue opening toward the dome of the combustion chamber to direct relatively cool air entering said flue opening towards the dome of the combustion chamber, a chambered door for closing said charging opening, the upper edge of said door defining an opening adjacent to the space along the front edge of said pouch shield, the lower edge of said door defining another opening for the admission of secondary air from outside said furnace to the chamber within said door.

5, In combination with a furnace comprising a combustion chamber closed at the top by a dome and provided with a front wall having a charging door opening, of a door for said opening comprising outer and inner panels spaced to provide a vertical flue coextensive with the width of the door, the door having air inlet openings from the exterior of the door to said flue at the bottomthereof and an air discharge opening at the top of the inner panel thereof del ve g o the interior of said combustion chamber, and a downwardly and forwardly inclined baifle spaced from the dome of the combustion chamber and disposed with its front edge adjacent but below the air discharge opening of said door so that the air is discharged from the door flue above said baffle, said baffle and said front wall of the combustion chamber being spaced and forming a passageway disposed to direct air leaving said discharge opening towards the dome of the combustion chamber.

6. In combination with a furnace comprising a combustion chamber closed at the top by a dome and provided with a front wall having a charging door opening, of a door for said opening comprising outer and innerpanels spaced to provide a flue, the door having an air inlet opening from the exterior of the door to said flue at the bottom thereof and an air discharge opening at the top of the inner panel thereof delivering to the interior of said combustionchamber, and a downwardly and forwardly inclined bafiie spaced from the dome of the combustion chamber and disposed with its front edge adjacent the air discharge opening of said door so that the air is discharged from the door flue above said baffle.

THOMAS H. POLAD.