US1953570A - Furnace - Google Patents

Description

Apr-il 3, 1934. H, w, sowARD 2 Sheefs-Seet 1 Filed March 25, 1931 April 3 1934- H. w. sowARD 1,953,570

FURNACE Filed March 25. 1931 2 Sheets-Sheet 2 Patented pr. 3, 1934 UNITED STTE` A TENT FFICE FURNACE Application March 25,

1931, Serial N0. 525,255

In Great Britain May 1, 1930 7 Claims.

This invention relates to furnaces for the melting of metals and the heat treatment of metal articles, and will be described illustratively in relation to two constructions as embodied in two diiferent kinds of furnaces.

An object of the invention is the provision of improvements in or in connection with the adm mission of the gaseous fuel and the aizl and with their mixing and combustion.

Another object of the invention is the provision of improvements whereby the direction of the stream of burning fuel may be directed relatively to the metal or article undergoing heat treatment.

A feature of the invention is a metal melting or heating furnace in which the gas and the air for its combustion are admitted to the furnace chamber through a central gas port and three air ports, the latter situated as to two 0n opposite sides of the gas port and directed to cause the air to flow towards and mingle with the gas in front of the gas port, and as to the third, above the central gas port and directed to deliver the air so as to mix with the gas and the air which issues from the ports on opposite sides of the gas port.

According to another feature of the invention a preliminary mixing' chamber is provided bee tween gas and air ports arranged as justI described and the furnace chamber proper.

A further feature of the invention is concerned with improvements in a furnace which is of the type referred to and in which the dames and products of combustion pass continuously in one general direction from end to end of the furnace chamber proper, which. improvements comprise means whereby air issuing from the third air port hereinbefore referred to may be directed either towards the line of the gas stream issuing from the gas port or along the furnace crown.

i The several features of the invention will bem come apparent to those skilled in the art from 5 the following description, in conjunction with the accompanying diagrammatic drawings, of the aforementioned illustrative constructions.

In the drawings,

Fig. 1 shows a longitudinal sectional View of the first illustrative construction,

Fig. 2 shows a section on the line A-B of Fig. l.

Fig. 3 shows to an enlarged scale the right hand or ring end of the furnace shown in Fig. l;

Fig. 4 is a section on the line C-D of Fig. 3;

(Ci. 26S-15) Fig. 5 is a longitudinal section of one end of the second illustrative construction;

Figure 6 is a vertical sectional view on the line E-F of Fig. 5.

Figure 7 is a horizontal sectional view on the line G-H of Fig. 6.

The iirst illustrative construction will now be described with reference to Figs. 1 to 4, which indicate a furnace in which the flames and prod-I ucts of combustion pass continuously in one direction from end to end of the furnace chamber proper.

1 is the combustion or furnace chamber proper and 2 is the crown or roof which is hollow to constitute an air space 3. 4 is a preliminary mixing chamber between the gas and air ports and the furnace chamber proper'. 5 is a central gas port, and 6 and 7 are air ports situated on opposite sides of the gas port 5 and directed to cause the air to flow towards and mingle with the gas in front of the gas port. A third air port 8 is provided above the gas port. 9 is a valve or damper pivoted on trunnions 10 and having an extension 11 engaged by the end of a threaded rod 12 having an operating hand- .wheel 13. The valve or damper 9 is accommodated in a recess 14 in the wall of the furnace and when in such position it forms the bottom and downwardly sloping wall of the air port 8 and the air is delivered so as to mix with the gas and the air issuing from the ports 6 and 7. By operating the handle 13 the valve or damper 9 may be moved to a horizontal position shown in dotted lines in Fig. 3 whereby the air stream may be directed more or less horizontally along the upper part of the furnace chamber. 15 is the gas inlet delivering to the gas port 5. The air for combustion enters at 17 and 18 and passes along the passage 19 under the hearth 20 to a blower 21 by which it is supplied through the passage 22 to the space 3 in the roof or crown and thence to the air ports 6, 7 and 8. The products of combustion pass through the space 23 above the space 3 to the chimney iiue 24. The air for combustion flowing under the hearth and through the space 3 is thus preheated before delivery to the combustion chamber.

The side walls 25, 26 of the preliminary mixing chamber 4 are directed towards each other as they approach the furnace proper.

in use the air streams delivered by the ports 6, '7 are directed towards each other and thegas stream is delivered to the point of mixing of said air streams so that considerable turbulence and mixing of the air and gas is obtained. This is assisted by delivering the air from the gas port 8 downwards to the point of mixing of the gas and the air streams delivered by the ports 0, 7. By varying the position of the Valve or damper 9 the ame may be directed downwards on to the stock or material being treated in the furnace or along the rooi1 of the furnace as desired. Thus when it is desired tc discharge material from the furnace the air stream flowing through the port 8 may be directed along the roof of the furnace.

The constricted opening between the preliminary mixing chamber 4 and the furnace proper produces more satisfactory and complete combustion of the heating medium.

Referring to Fig. 5, 6 and '7, these figures indicate the aforementioned vsecond illustrative construction as embodied in one end of one form of reversing regenerative furnace; the other end of the furnace is similarly constructed. The ports at each end of the furnace serve alternately as admission ports for the fuel gas and the air, and as exhaust ports for the burnt gases. As the first construction has been described in detail it will be necessary in this case to describe merely the chief parts.

Two air ports 106 and 107 are situated on opposite sides of a central gas port 105 and with the gas port deliver into a preliminary mixing chamber 104 disposed between the ports and the furnace hearth of the combustion chamber 101. The two air ports 106, 107 are directed to cause the air to flow towards and mingle with the gas in front of the gas port 105 as indicated in Fig. 7. A third air port 108 is provided above the gas port 105 and is directed so as to deliver its air to the point of mixing of the gas and of the air from the two side ports. An exactly similar arrangement is providedat the other end of the furnace.

In the case of a reversing regenerative furnace a valve or damper such as 9 of Figs. l to 4 is not provided since it would be liable to be comparatively rapidly destroyed owing to the heat of the burnt gases when the port with which it was associated was serving as an exhaust port.

The side walls of the preliminary mixing chambers 104 may be directed towards each other as they approach. the furnace chamber, for example, as indicated in Fig. '7.

The air ports are connected by uptakes as 130 with regenerators as 131 in the usual way and the air is supplied under pressure.

By directing the air streams to mix together at a xed point their kinetic energy is largely destroyed by the turbulent mixing which takes place and the gas is directed into the turbulent mixture. A slow velocity of the gases through the furnace chamber and the exhaust ports is thus produced, whereby combustion of the gases is completed in the furnace chamber and consequent destruction of the port ends is reduced.

Water cooling of the mixing chambers and/or the gas and air ports may be provided.

The quantity of air supplied through any of the ports may he regulated by inserting lling pieces in the ports as required.

What I claim is:-

1. A furnace comprising a combustion chamber and a preliminary vmixing chamber in communication therewith, a gas port delivering into said mixing chamber, an air port situated at each side of the gas inlet port and discharging obliquely across said gas port and into said preliminary mixing chamber to cause air to flow .towards and mingle in front oi' the gas port with the gas issuing from said port, a third air port positioned above the gas port and discharging obliquely downwardly across the end of the gas inlet port and into said preliminary mixing chamber to mix with the gas and air issuing from the aforementioned gas and air ports, for the purpose described.

2. A furnace comprising a combustion chamber and a preliminary mixing chamber in communication therewith, a gas port delivering into said mixing chamber, an air port positioned immediately adjacent each side of said gas port and having a discharge opening of a height at least as great as the height of the discharge end of said gas port, said air ports discharging obliquely into said mixing chamber across the inlet end of the gas port to cause air to iiow towards and mingle in front of the gas port with the gas issuing therefrom, a third air port located immediately above the gas port and having an outlet end of a width at least as great as the outlet end of the gas port, and said third air port discharging obliquely downwardly into said mixing chamber across the outlet end of said gas port to cause its air discharge to mix with the gas and air issuing vfrom the two aforementioned air ports and gas port, for the purpose described.

3. A furnace comprising a combustion chamber and a preliminary mixing chamber --in communication therewith, a gas port delivering into said mixing chamber, an air port positioned at each side of said gas port and discharging obliquely into said chamber across the outlet endof vsaid gas port, a third air port positioned immediately above the gas port and normally discharging obliquely downward into said mixing chamber across the outlet end of said gas port, a defiector in said third air port and means for operating the same, and said'deiiector adapted to be adjusted to direct the air issuing from said third air port horizontally outwardly from said port and away from the impinging streams of air and gas issuing from the aforementioned air and gas ports, for the purpose described.

4. A furnace comprising a combustion `chamber and a preliminary mixing chamber in communication therewith, a gas port delivering into the bottom of said mixing chamber, an air port at each side of said gas port and deliveringhorizontally and obliquely into said mixing chamber' and across the outlet end of said gas port, a third air port positioned immediately above the gas port and delivering obliquely downward into said mixing chamber across the outlet end of said gas port, an air inlet, an air passageway in the top of said combustion chamber, said air inlet communicating with said air passageway at a point remote to all of the air ports, and all of the air ports having communication with said air passageway to receive preheated air therefrom, for the purpose described.

5. A furnacecomprising a combustion chamber and a preliminary mixing chamber in communication therewith, a gas port delivering into said mixing chamber, an air port immediately above said gas port and discharging obliquely downward thereinto and across the outlet end of said gas port, a deflector in the lower Wall of said air port and adapted to be positioned' to permit said air port to normally discharge as defined, and means to move said deflector to direct the air discharge from said port outwardly therefrom in a horizontal plane, for the purpose described.

6. A furnace comprising a combustion chamber, a gas port delivering into said chamber, a air port positioned above the gas port and having its bottom wail arranged to direct the air discharge from said port obiiqueiy downward into said chamber and across the outlet end of said gas port, said bottom wall formed with a depression, a movably mounted deector arranged in said depression, and means for moving said deiiector whereby the deflector directs the air discharge from said port outwardly therefrom in a horizontal direction, for the purpose described.

7. A furnace comprising a combustion chamber and a preliminary mixing chamber in communication therewith, a gas port delivering into said mixing chamber, an air port at each side of said gas port and discharging horizontally into said mixing chamber and obliquely across the outlet end of said gas port, a third air port positioned above the gas port and having an obliquely inciined lower wall for causing the said port to discharge air obliqueiy downwardly into said mixing chamber and across said gas port, an air inlet, an air passageway in the top of said combustion chamber and having communication with said air inlet at a point remote to said air ports, said air passageway having communication with the said ports at the opposite sides of the gas port, a vertical passageway forming a communication between said rst named air passageway and the third air port having the obliquely inclined bottom wall, a movable deector in said third air port, and means to manipulate said deector to direct the air discharge from said port in a horizontal plane outwardly from the discharge end of said port, for the purpose described.

HENRY WILLIAM SOWARD.

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