US2983499A

US2983499A - Method and apparatus for heating ingots

Info

Publication number: US2983499A
Application number: US700654A
Authority: US
Inventors: Clarence W Sidwell
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1957-12-04
Filing date: 1957-12-04
Publication date: 1961-05-09
Anticipated expiration: 1978-05-09

Description

2 Sheets-Sheet 1 Filed D60. 4, 1957 AAI y W A m 2 E 5 m M P u. C

w A w P A 6 I /nUN/// f//U p 2 United States Patent METHOD AND APPARATUS FOR HEATING INGOTS Clarence W. Sidwell, Homewood, Ill., assignor to United States Steel Corporation, a corporation of New Jersey Filed Dec. 4, 1957, Ser. No. 700,6'54

'5 Claims. (Cl. 263-15) ICC 2 and 22, respectively. The openings and 22 are lo-v cated along one side wall of the chamber 4 at the bottom thereof with one opening being located at each end of the side wall. The iiues 1 6 and 18 are preferably long and extend from the main building (not shown) so as to provide an open area A in the lean-to basement for handling cinder and scale. The regenerators 12 and 14 have a connecting `lue 24 with the usual four-way reversing valve 26 therein. One side of the valve 26 is connected to a fan 27 through a conduit 28land another conduit leads to the stack (not shown) in a conventional manner.

Burner ports

32 and 34 are provided in

flues

16 and 18, respectively, fuel being supplied thereto through a conduit 36 having a three-wayfvalve 38 therein. Burner ports 40 and 42 are provided in the side wall,

, preferablyv above the

openings

20 and 22, respectively, and discharge fuel into the chamber 4 above the top 'of ered to be gaseous fuel having a caloric value of 300 Y B.t.u. per cubic foot or more. Powdered coal or liquid fuel having corresponding caloric values will also be considered as high caloritic fuels. Prior to my invention high caloriiic fuels were generally introduced into regenerative soaking pits below they top of the ingots. In recuperative soaking pits fuel may be introduced into the pit either above or below the tops of the `ingots. In these types of soaking pits the high caloric' fuel caused washing of the ingots When the temperature differential across ya horizontal section of the ingot was low. In other words, when the ingots became hot throughout so thatthe heat was not rapidly transmitted from the outside to the inside, washing would occur. When using a regenerative type furnace, the preheated air and fuel were generally mixed in the burner port. This resulted in a relatively hot chill Wall at the slag line.

It is therefore an object of my invention to provide a soaking pit which can use high calorilicv fuel without damage to the ingots and which eliminates the need of a chill wall.

Another object is to provide a soaking pit having .accessibility for handling cinder Iand scale inA the lean-t0 basement area.

Still Yanotherl object is to provide a method of heating ingots eciently with high caloric fuel.

These and other objects will be more apparent after referring to the following specication and attached drawings, in which: Y p

Figure 1 is a schematic plan view, partly, in section, of a regenerative furnace according to my invention;

Figure 2 is a sectional view taken on the line II-II of Figure 1;

Figure 3 is a sectional view taken on -the line III--III of Figure 2;

Figure 4 is a view similar to Figure 1 showing my invention in a recuperator furnace; and

Figure 5 is a view taken on the line V-V of Figure 4.

Referring more particularly to Figures l to 3 of the drawings, reference numeral 2 indicates -a soaking pit having lan elongated chamber 4 for receiving ingots S to be heated. Two rows of ingots are shownin the chamber. The top of the chamber 4 is located approximately at floor-level F. The soaking pit 2 is supported on framework 6 and a cleanout door 8 is provided in the bottom of the chamber 4 to permit ready removal of the cinder and scale which accumulates in the chamber. 10. Two regenerators 12 and 14 are provided some distance from the chamber 4 and `are connected thereto by means of flues 16 and .18, respectively. The

ilues

16 and 18 discharge into the chamber 4 through openings 20 The ingots S are supported on the usual coke bed V the chamber 4 through burner ports 40 and 42.

vthe ingots S. Fuel is provided to the burner port 40 through a conduit 44 having a valve 46 therein and to burner port l42 through a conduit 48 having a valve 50 therein.

` The operation of the soaking pit is as follows:

The ingots S are charged into the chamber 4 as shown and valve 26 is arranged so that air is drawn through the regenerator 12 where it is heated and delivered through the flue 16 to the chamber 4. The valve 38 is set so that the fuel passes through port 32 into the flue 16 Where it burns and gives added preheat to the air above the ingot' temperature prior to its entry into the chamber 4. This prevents chilling of hot ingots. Fuel is also delivered to There may be three paths of burning gases in the chamber 4 as shown in solid lines in Figure 3. One path is from the burner 32 through the flue 20 and chamber 4 in a horizontal direction to the llue 18. Another path is diagonal from the burner ports 40 to the flue 22.A The third path is vertical from the burners 42 to the flue 22. After a period of time which may be between three to ten minutes, the valves 26 and 38 are reversed so that air is heated in the regenerator 14 and the flue gas passes outwardly through the iiue 16 and regenerator 12. The air passing through the flue y18 is heated by fuel from the burner 34 and no fuel enters the ue 16 through the Iburner 32. Here, too, there may be three paths of burning gases through the chamber 4, as shown in broken lines in Figure 3, a horizontal path from openings 22 to 20, a verticalpath from burners .40 to flue 16 and a diagonal path from burners 42 to flue 16. After operat-` ing in [this manner for approximately three to ten minutes the valves 26 and 38 are reversed so that the condition of the burners and lines is back to that originally described. The cycle is then repeated until the ingots reach the desired temperature. Control of fuel to the

burners

32, 34, 4t) and 42 may be varied according to the requirements of the heating cycle. During the early heating stages all of the heat may be provided by

burners

32 and 34 alternately and at all times at least part of the heat will be provided by these burners. After the ingots become hotter additional heat will be provided from the burners above the flue providing air. still additional heat may be provided fromthe other set of top burners. l

I n the embodiment of Figures 4 and 5 a soakingpit 52 has a heating chamber 54 for receiving the ingots. A

vflue 56 leads from a recuperator 58 to the bottom of the Y chamber 54 in the same manner as in Figure 2. A flue 60 for the waste gases leads from the chamber 54 to the recuperator 58. A burner port `62. is provided in the iiue 56 in the same manneras in Figure 2. I Fuel is delivered to the port 62 through a conduit 64 having a valve 66 therein. v Burners 68 are providedkabove the Hue 56- and Afuel is delivered thereto through a conduit 70 having a At the same timel valve 72 therein. The construction is otherwise the same as that of the embodiment of Figures 1 to 3.

In operation the ingots S are charged into the chamber 53 and heat is supplied through the burner 62. After the ingots have reached a predetermined temperature additional heat is provided by turning on the valve '72 and permitting fuel to flow through the burners 63;V The hot gases passing out through flue 6% heat the air in the recuperator d8.

While two embodiments of my invention have been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. The method of heating ingots in a soaking pit hav-` ing heat recovery means which comprises charging ingots into a chamber having a ue adjacent the bottom thereof, introducing hot air into the bottom of said chamber through said flue, introducing fluel into said due, and after the ingots have reached a predetermined temperature discharging a high calorific fuel into said chamber adjacent the top thereof, and regulating the flow of fuel into said chamber according to the requirements of the heating cycle.

2. The method of heating ingots in a regenerative Soaking pit which comprises charging ingots into an elongated chamber having two bottom openings along one side wall thereof adjacent its ends leading to the regenerators, discharging a high caloric fuel into said chamber above the top of said ingots and over said openings after the ingots have reached a predetermined temperature, discharging heated air from the first of said regenerators through its associated opening into said chamber, introducing fuel into said heated air prior to its discharge into said chamber, exhaustng flue gases through the other said opening to the second of said regenerators, regulating the flow E fuel into said chamber according to the requirements of the heating cycle, after a period of time reversing the ow of flue gas and air to said regenerators, and discontinuing the ow of fuel into the air from the rst of said regenerators and introducing fuel into the heated air from the second of said regenerators prior to its discharge into said chamber after another. period of time returning the ilow of ue gas, air and fuel into the air to that originally set forth, and repeating the cycle.

3. A soaking pit for heating ingots comprising a chamber for receiving ingots, a heat exchanger spaced from said chamber, said chamber. having generally vertical I walls adapted to surround ingots to be heated, at least one of said walls having its surface substantially in a single vertical plane, a ilue extending from said heat exchanger to said one wall and having an outlet in said one wall adjacent the bottom of said chamber for delivering air into said chamber, means for introducing fuel into said flue, a burner in said one wall adjacent the top thereof at a higher elevation than the top of said ue and adapted for discharging fuel directly into said chamber above the top of said ingots, said burner having its outlet substantialiy in said vertical plane, and a due for withdrawing burnt gases from said chamber.

4. A soaking pit for heating ingots comprising a chamber for receiving ingots, said chamber having generally vertical walls adapted to surround ingots to be heated, at least one of said walls having its surface substantially in a single vertical plane, two regenerators spaced from said chamber, two spaced flues in one of said walls each having an outlet in said one Wall adjacent the bottom of said chamber, one of said ues leading to one of said regeneratorsand the' other ue to the other of said' regenerators, burners in said one wall adjacent the top` thereof at a higher elevation than the top of said ues and adapted for discharging fuel directly into said chamber above the top of said ingots, said burners having their outlets substantially in said vertical plane. f

5. A soaking pit for heating ingots comprising a chamber for receiving ingots, said chamber having generally vertical walls adapted to surround ingots to be heated, at least one of said walls having its surface substantially in a single vertical plane, two regenerators spaced from said chamber, two spaced flues in one of said walls each having an outlet in said one wall adjacent the bottom of said chamber,` one of said ues leading to one of said regenerators and the other ue to the other of said regenerators, burners in said one wall adjacent the top thereof at a higher `elevation than the top of said ues and adapted for discharging fuel directly into said chamber above the top of said ingots, said burners having their outlets substantially in said vertical plane, and a burner located in each of said flues.

Naismith et al. May 12, 1931 2,172,105y vParker Sept. 5, 1939 2,303,62Q

Dean Dec. l, 1942