US1809563A - Rotary furnace - Google Patents

Description

H. D. NEWKIRK ROTARY FURNACE June 9, 1.931.

. l l Filed June 18. 1929 2 Sheets Sheet l Num@ ., M. Y In W um E w @MEK m w. @,W/W v Y E N T T A June 9, 1931. H. D. NEwKlRK ROTARY FURNACE Filed June 18, 1929 2 Sheets-Sheet 2 l 'INVENToRL H. p. /vEwn/Rff BY mwmm' f i the Patented June 9, 1931 UNITED STATES PATENT OFFICE I HABLAN!) D. NEWIIBX, OF SYBACUSE, NEW YORK, ABSIG'NOB TO ONONDAGA STEEL OOMPANY, INC., A. CORPORATION OF N'EW YORK ROTARY rUnNAcE My invention relates to im rovements in rotary kilns or furnaces and re ates more p articularly to an improved means for sealing the 'oint between rotary and fixed parts' of urnace. My invention is particularly adapted for use 1n processes in which it is desirable to mixture of 'finely divided charge is heated zo s exclude air. For exam le, in a certain continuous process of pro ucing sponge iron, a iron ore and coal is subjected to heat in a rotary furnace, the heat being supplied by a fuel burner at the discharge end of the furnace which burner is furnished with a deficiency of air. The suiiiciently to convert the iron oxide into metallic iron, while a highly reducing atmosphere is produced by the carbonaceous gases from the coal andfrom the burner. It'is essential in a furnace of this iminated.- Heretofore, considerable diiiicult has been experienced in attemptin to exclude air at the discharge end of the urnace where the greatest heat is developed and where a joint must be provided vbetween the rota furnace and a fixed discharge head.

It 1s an object of my invention to overcome the diiiiculty by providing an improved seal ibletgeen the rotary furnace andthe discharge Another object of the invention is. to provide means for keeping the joint at the discharge head cool, so as to permit of keeping the joint properly lubricated.

Still another object of the invention is to maintain a partial vacuum around the bearing, so that incase of any leakage there will be an outow of gas at the bearing rather than an inow of-air therein.

. of a rotary kiln With these objects in view and others which will appear hereinafter, I shall described a preferred embodiment of my invention, and shall thereafter point' out Ythe novelty and scope of the invention in the claims.

In the accompanying drawings:

Figure 1 is a view in longitudinal section provided with my improved seal;

Fig. 2 is a similar view, but onv a larger that leakage of air into the furnace be.

1929. serial No. 371,797.

scae, of a portion of the kiln shown in Fig. 1; an

Fig. 3 is a view in section taken on the line 3-3 of Fig. 2.

As shown in Fig. -1, the furnace consists `of a rotary cylinder 1() suitably lined with firebrick and preferably mounted on a slight incline, so that the material fed into the u per end of the furnace will graduall work own to the lower or discharge end. ixed to the cylinder 10 near its upper or inlet end is an annular flange or rail 11 which runs on rollers 12 journale in a bracket 13 mounted on a suitable pedestal 14. Near the discharge end the furnace c linder is similarl provided with an annu ar rail 15 ada te .to run on rollers 16 mounted on a brac et 17 which'is supported on a pedestal 18. The bracket 17 also carries a roller 19 which turns on an axis normal to that of thecylinder 10 and bears against the side of the flange 15, so as to take the thrust due to the inclination lof the cylinder.

The upper end of the cylinder 10 projects into a stack 20 adapted to carry oif the products of combustion from the furnace, and the mixture of iron ore and coal is fed into the furnace from a hop er 21 through a chute 22 ed to engage the face ofthe flange 26. The

contacting surfaces of the ian e and member 27 are. greased soas to re uce friction and also to provide a seal at this oint. The bearing member 27 is formed wit a conduit 28 through which water is circulatedto keep the bearingsurfaces relatively cool and revent va orlzing-or carbonizing of the lu ricant. urrounding the water conduit 28 is an air conduit 29 which is open at the sidev adjacentthe flange 26; in the other words,

the fiange 26 forms one of the walls of the air conduit. lMounted on the discharge head 24 is a suction fan 30v driven by a suitable motor 31 and connected to the air conduit 29. By this means air is constantly being drawn out of the air conduit, maintaining a partial vacuum around the bearing ring or water conduit 28, so that any leakage which may occur at the joint between the bearing ring 2,7 and iange 26 will be outward in the direction of the air conduit.

, It will be understood that. this form of seal is articularly adapted for large furnaces w ch, because oftheir size and the weight of material they are apt to carry and alsovbecause of variations of temperature to which the are subjected, are likely to be distorted. ny bearing member such as the `iiange 26 secured to the end of such a furnace is apt to wobble as it rotates. Because of the ravitational bias of the discharge head towar the disk produced by the incllnation ofthe suspension links 25, the bearing ring 27 will follow the irregular movements of the disk 26 and maintain contact therewith.

As shown in the drawings, the discharge head 2A is formed with a combustion chamber 32 which projects into the furnace 10 and at its upper end is conically tapered .to a small diameter as indicated at 33. A burner (not shown) serves to feed a spray of fuel into the combustion chamber 32 with just suiicient air to supportcombustion, but the deficiency of air is such that a lhighly carbonaceous gas is produced. The combustion chamber 32 and also the discharge head 24 are suitably lined with firebrick or other refractory material, and the discharge head is provided with a discharge spout 34 which leads into a hopper 35 communlcating with a cooling drum or cylinder 36. In a furnace of this type, it is desirable to keep the charge out of Contact with air not only at the point of discharge from the furnace, but also thereafter, until its temperature has been'reduced to a point be-' low that at which serious oxidation could take place by exposure to air. Because the discharge head must oscillate in order to maintain contact with the disk 26, a flexible joint must be provided between the hopper 35 and the spout 34. To this end the hopper is formed with a fixed waterjacketed intake spout 37, as best shown in Fig; 2, which is provided at the top with an'annular trough 38 adapted to be filled with oil. Water is circulated through the water space 39 in the spout 37 to keep the oil from becoming too hot and evaporating.

The discharge spout 35 terminates in a fiting 40 which enters the intake spout 37 and which is provided with a depending annular iian 41 adapted to dip into the'oil contained in t e trough 38. Thls connection provides `an air seal with a certain freedom of movement between the spot 34 and the spout 37.

The mixture in the cylinder 10 discharges through the hopper 35 into .the cooling drum 36 and is cooled by a Spray of water from a spray-pipe 42. The cooling drum 36 is preferably inclined, so that the material will gradually feed from the hopper to the our,- let end of the drum where it 1s picked up by paddles 43 and discharged into a tube 44, and

thence into a weighing hopper 45. The lat-Y -ter is conically tapered and opens at its lower end upon a suitable support 46. The hopper 45 is suspended from a scale beam 47, and vwhen suflicient material has accumulated in the hopper to overbalance a counterweight 48 on the scale beam, an electrical contact will be made at 49, closing the circuit of an alarm 50, which will indicate'to an attendant that sufficient material has accumulated to require withdrawal from the support 45.

I do not claim as part of my invention the construction of the cooling drum or the weighing hopper 44 and associated parts. They are illustrated here merely to show how a continuous process of reducing the ore is maintained without any chance for air to come in contact with the ore until the latter has been roperly reduced and cooled to a predetermmed temperature.

l. In a furnace a rotary cylinder and a bearing therefor, and suction means for producing a partial vacuum surroundin the area of engagement of the bearing an cylinder.

2. In a furnace 4a rotary cylinder and a bearing therefor, suction` means for producing a partial vacuum surrounding the area of engagement of the bearing and cylinder, and means for cooling said area.

3. In a furnace ycomprising a rotary cylinder and a non-rotary head at one end of the cylinder, a pair of mutually engaging bearing members formed on the head and cylinder respectively, said members being formed to.

provide a conduit therebetween surrounding the bearing surfaces of the members, and suction means connected with said conduit.

4. In a kfurnace com rising a rotary cylinder and a non-rotary ead at one end of the cylinder, a pair of mutually engagin bearing members formed on the head an cylinder respectively, said members being formed to provide a conduit therebetween surrounding the bearing surfaces of the members, and suction means connected with said conduit, one of said members being water-jacketed.

5. In a furnace comprising a rotary cylinder and a non-rotary head at one end of the cylinder, -an annular flange on said end of the cylinder, saidhead being formed with an annular bearing surface adapted to engage the iange and with a channel surrounding vthe bearing surface, and a suction pump conthe cylinder,

inder and a non-rotary head at one endof the cylinder, an annular flange on said end of the cylinder, said head bein provided with an annular bearing adapte to engage the flange, said flange and bearing member being formed to provide an air conduit therebetween, and a suction pump connected withsaid conduit.

7. In a furnace comprising a rotary cyly inder and a non-rotary head at one end of the cylinder, an annular iange on said end of the cylinder, said head being rovided with an annular bearing surface a apted to engage the flange and with a channel surrounding the bearing surface, and a suction pump mountedon the head andV connected with said channel.-

8. In a furnace comprising a rotary cylinder and a non-rotary ead at one end of the cylinder, an annulariiiange on said end of the cylinder, said head belng provided with an annular bearing surface adapted to engage the flange and with a channel surrounding the bearing surface, a suction pump mounted on the ead and connected wit said channel, and a motor operatively connected with the pump and also mounted on said head.

9. In a furnace comprising a rotary cylinder and a non-rotary head at one end of the cylinder, an annular Bange on said end of said head being provided with an annular bearing surface adapted to engage the flange and with a channel surroundmg the bearing surface, and a suction pump connected with said channel, said member being also formed with a duct adjacent the bearin g surface through which a cooling fluid may be passed.

In testimony' specification.

HARLAND D. NEWKIRK.

whereof, I have signed this

Images