US2843402A - Gas seal for relatively rotating tubular parts of a blast furnace - Google Patents

Description

5, 1958 G. HOOKHAM 2,843,402

GAS SEAL FOR RELATIVELY ROTATING TUBULAR 2 Sheets-Sheet l PARTS OF A BLAST FURNACE Filed Aug. 25, 1954 v FIG. I

July 15, 1958 G. HOOKHAM GAS SEAL FOR RELATIVELY ROTATING TUBULAR PARTS OF A BLAST FURNACE 2 Sheets-Sheet 2 Filed Aug. 25, 1954 United States Patent-O GAS SEAL FOR RELATIVELY ROTATING TUBU- LAR PARTS OF A BLAST FURNACE George Hookham, London, England, assignor to John Miles & Partners (London) Limited, London, England,

The present invention relates to an improved sealing device between the relatively rotating members of a blast furnace top.

A preferred form of. the invention will now be described with reference to the accompanying diagram matic drawings in which:

Figure 1 is an elevation, partly in section, showing the general lay-out of a known type of blast furnace top, and

Figures 2 and 3 are respectively sectional elevations through portions of two alternative forms of furnace top constructed in accordance with this invention.

The normal blast furnace illustrated in Figure 1 comprises a stack having an open mouth in which is secured a large hopper 11 which is usually of inverted frusto-conical shape, upwardly and outwardly flaring, projecting downwardly a short distance into the mouth of the furnace and having its lower end closed by what is called the large bell 12.

This bell is conical in shape and is carried by a rod 13 the upper end of which is hung on a quadrant chain 14 and lever 15 by which the bell 12 can be raised and lowered to close and open the furnace mouth.

The large hopper 11 is covered over by a conical roof 16 having a central aperture in which is fixed a short length of cylinder 16A extending upwardly from the roof.

Seated in this cylindrical portion of the large hopper, is a small hopper 17 in the form of a cylinder which is rotatable with respect to the large hopper. The lower end of the small hopper 17 extends downwardly inside the fixed cylindrical portion of the large hopper and the lower end of the small hopper is closed by a small conical bell 18 secured to a tubular sleeve 19 surrounding the large bell rod 13 and movable independently thereof.

For this purpose the sleeve 19 is provided at its upper end with a ball-bearing 20 the casing of which is connected by links (not shown) to a lever 21 with which the small bell 18 is raised and lowered.

The two bells and their respective hoppers are used, in a manner which is well-known, to permit charge materials to be lowered into the furnace without the escape of any substantial quantity of gas from the furnace, and the small hopper is rotated intermittently in order that the charge carried by it may be distributed more uniformly in the furnace.

It has been found, however, that the parts frequently distort in shape with the result that one hopper becomes eccentric with respect to the other. Accordingly it is also known to provide means for holding the two hoppers in coaxial alignment during rotation.

In known furnaces, therefore, the joint between the hoppers and the aligning mechanism each exerts constraint on the movement of the small hopper.

If distortion occurs in either or both of these mechanisms binding takes place, and it is one object of the present invention to minimize the risk of such binding.

Another difiiculty experienced with the known type of blast furnace top is that of dismantling the two bells for ICC repair or replacement. It is usual to make the small bell and its supporting sleeve and the small hopper in two parts bolted together so that theycan be dismantled and assembled, around the rod 13, transversely as it were.

It is obvious, however, that it would be desirable to make the various members, such as the small bell and hopper, each of unitary structure.

In an earlier furnace top which I devised I provided removable hooks at the positions 22 and 23 shown in broken lines in Figure l, with the aid of which the large bell 12 could be secured to the roof of the large hopper 16. I also made the joint 24 a separable one so that when the large bell 12 had been secured to the roof of its hopper 16 with the aid of these hooks, the rod 13 could be withdrawn upwardly through. the sleeve 19 after which the small bell and hopper could be removed transversely away from the furnace top for repair or replacement.

It is an object of this invention to simplify and improve the means for holding the two hoppers in concentric alignment whilst retaining the advantage of making each of the several members of unitary construction.

According to this invention a blast furnace top comprises a fixed large hopper having a roof, a rotatable small hopper projecting into the roof, an expansion bellows between the two hoppers, and at least one annular antifriction bearing located between the two hoppers so as to support forces in both opposite radial directions and in at least one of the opposite axial directions.

One or two bearings may be used between the two hoppers and each bearing is preferably unsplit radially, i. e. is in the form of a continuous ring.

Preferably also the large bell is removably coupled to its rod and the small bell and hopper are each of unitary structure. 3

One form of the invention is illustrated in Figure 2. In this embodiment two bearings are used between the two hoppers.

A portion of the roof of the large hopper is shown at 25 and a portion of the rotatable cylindrical small hopper at 26. p

The roof 25 is permanently stationary and to it is attached a short cylindrical extension 27 formed with an external flange 28 to which is bolted an annular plate 29 carrying a bearing ring 30 the upper surface 31 of which bears against an upper bearing ring 32 rotatable with the small hopper 26.

The plate 29 also carries an outer cylindrical casing 33 formed with apertures such as 34 through which access may be had to oiling channels 35 leading to grooves 36 in the bearing surface 31 of the lower bearing ring 30.

At its upper end the casing 33 is bolted to a housing consisting of two rings 37, 38 for a pair of annular ballbearings indicated generally at 39 and 40.

The rotatable small hopper 26 has bolted to its upper end a ring gear 41 meshing with a pinion 42 by which it may be rotated periodically.

Intermediate in its length the small hopper is formed with an external boss 43 which in turn is formed with an external flange 44 projecting into the space between the two bearings 39 and 40.

Below the boss 43 the small hopper is formed with an external flange 45 to which is bolted an expansion bellows 46 carrying at its lower end the upper bearing ring 32.

In order that the two bearings 39 and 40 may constrain the small hopper to maintain its concentric position with respect to the large hopper, the upper race 47 of the upper bearing 39 bears externally against a shoulder 48 in the upper housing ring 37 and the lower race similarly bears against the small hopper at 49. In an analogous manner the upper race 50 of the lower bearing 40 bears against the hopper at 51 and the: lower race 52 Patented July 15, 1958 3 bears against a shoulder 53 formed in the lower housing ring 38. A small amount of play, transverse to the common longitudinal axis of the two hoppers, is permitted by the clearance at 54 between the outer face ofitheflange 44 andthe inner face of the housing 37; 38, and by virtue of the fact that the upper bearingiring 32 can slide on the lower ring 30.

Longitudinal play between the two hoppersdue to clearance and wear of the bearings, is accommodated by the expansion bellows 46, which is normally under compression. a

The load on the two bearings 39 and 40 received from the hopper flange 44 may be either upward or downward depending mainly upon whether the small hopper is closed or open and, if closed, the amount of charge in it. The bellows is, however, initially compressed to ensure that rubbing contact is permanently maintained between the two rings 30 and 32. v

The only point at which gas can escape is between the two rings 30 and 32 and any small quantity thus escaping passes to atmosphere through the apertures such as 34.

Dust seals are shown at 55 and 56.

With ball-bearings of the size necessary for a blast furnace top it would be usual to split the rings so that they can be assembled transversely. With the present invention, however, full or unitary rings can be used in the following way.

During assembly and before the expansion bellows 46 is assembled in position the upper ball-bearing 39 is brought downwardly on to the flange 44 and the lower bearing 40 is brought upwardly to the flange 44. The

housing rings 37, 38 are then secured in position with the aid of screws 57. The expansion bellows is then bolted to the small hopper 26, the parts thus assembled are then lowered untilcontact is made between the two bearing rings 30 and 32 which will leave a gap 58 between the cylinder cover 33 and housing 38, compression in the bellows being produced by tightening up bolts 59 to close the gap.

' Provided the large bell 12 (Figure l) is attached to its rod 13 so that it can be uncoupled, and provided that it (i. e. the rod 13) is small enough in diameter to be passed through the small bell supporting sleeve 19 the various members such as the small bell, its rod and the small hopper may each be made of unitary structure and can be disassembled transversely in the manner which I prefer and which has been described above.

In certain circumstances a single, unsplit ball-bearing may be used in place of the pair shown in Figure 2. This might be done, for example, if the expansion bellows remains under compression during the full working cycle I of the two bells.

Such an arrangement is illustrated in Figure 3. Here the small hopper is shown at 60, the large hopper roof at 61, the bellows at 62, the casing at 63 and the ring gear and pinion at 64 and 65.

The small hopper is formed witha boss 66 having an external flange 67 shouldered at 68, and the casing 63 is secured to a lower ring 69 bolted to an upper ring 70 shouldered at 71.

The two rings and the boss together house a single, unsplit annular ball bearing 72.

The bellows is loaded so that axial thrust between the small and large hoppers remains at all times in the same sense, this thrust being taken by the upper ring 70 (which is rigid with the large hopper) and the flange 67 on the small hopper. Radial thrust is supported by the two shoulders 68 and 71.

In either embodiment the ball bearings may be replaced by any other suitable form of antifriction bearing, such as roller bearings.

In the following claim the expression large hopper is intended to include the roof .of the large hopper.

What I claim is:

A blast furnace top comprising a large and a small hopper, an external flange formed on the small hopper, an expansion bellows having its upper end removably secured to the small hopper, an annular upper bearing ring recured to the lower end of the bellows so as to be spacedfrorn the small hopper, a casing secured to the large hopper surrounding and spaced from. the bellows, an annular lower bearing ring disposed on the casing normally in resilient sliding contact with the upper bearing ring and also spaced from the small hopper, a housing removably secured to the casing, an internal flange on the housing, and an anti-friction bearing housed between the external flange on the small hopper and the internal flange on the housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,040,643 Darnley Oct. 8, 1919 1,819,417 Holmgreen Aug. 18, 1931 1,936,374 Barks Nov. 21, 1933 2,118,681 MacDonald May 24, 1938 2,486,312 Mohr et al. Oct. 25, 1949 2,501,680 King Mar. 28, 1950 2,549,951 Warren Apr. 24, 1951 2,565,296 Chyle Aug. 21, 1951 2,655,391 Atkins Oct. 13, 1953

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