US3026102A

US3026102A - Hood post crane

Info

Publication number: US3026102A
Application number: US722257A
Authority: US
Inventors: Harry L Mcfeaters
Original assignee: Pennsylvania Engineering Corp
Current assignee: Pennsylvania Engineering Corp
Priority date: 1958-03-18
Filing date: 1958-03-18
Publication date: 1962-03-20
Anticipated expiration: 1979-03-20

Description

March 20, 1962 H. L. MCFEATERSQ HOOD POST CRANE l6 Sheets-Sheet 1 Filed March 18, 1958 RAMP. DOW/V RAMP- aanw l J rlllL March 1952 H. L. MOFEATERS 3,025,102

HOOD POST CRANE Filed March 18, 1958 16 Sheets-Sheet 2 March 20, 1962 H. L. MCFEATERS HOOD POST CRANE l6 Sheets-Sheet 5 Filed March 8, 8

RAMP. DOWN March 20, 1962 H. L. MCFEATERS H0013 POST CRANE l6 Sheets-Sheet 4 Filed March 18, 1958 INVENTORI A/ARRYL MCFEA TE'RS BY 5AM HIS/4 7TOR/VE -S'.

March 1962 H. L. MCFEATERS 3,026,102

HOOD POST CRANE MT I Z nvs 1 i I I- L INVENTOR. HARRY l Mc/Ts-A TE'RS HIS 1477OR/VEYS.

March 20, 1962 H. L. MCFEATERS 3,026,102

HOOD POST CRANE Filed March 18, 1958 16 Sheets-Sheet e IIG. 3])

v INVENTOR. HARRY L. Mc FEATERs ym cama 1w HIS ,4 TTORNE'YS.

March 20, 1962 H. L. MGFEATERS HOOD POST CRANE l6 Sheets-Sheet 7 Filed March 18, 1958 INVENTOR.

m eam 1% #13 ATTORNEYS.

March 20, 1962 H. L. MGFEATERS HOOD POST CRANE 16 Sheets$heet 8 Filed March 18, 1958 March 20, 1962 H. L. M FEATERS 3,026,102

HOOD POST CRANE Filed March 18, 1958 16 Sheets-Sheet 9 a FIG. 7

INVENTOR. HARRY L MCFEA TERS gan hm 0W4 HIS ATTORNEYS.

March 20, 1962 MCFEATERS 3,026,102

HOOD POST CRANE \98- I her-.13

{w a5 7? 1 [I L as as l 64 I l 3 2 I028 me [08 50 /OZ 85 o 3/ mm E HARRY L McPs-A TERS BY. M ZJJ%Z% V H S ATTORNEYS.

16 Sheets-Sheet 11 H. L. M FEATERS HOOD POST CRANE March 20, 1962 Filed March 18, 1958 RE M, o QH March 20, 1962 Filed March 18, 1958 H. L. M FEATERS 1-1001) POST CRANE 16 Sheets-Sheet 12 IVA/W?! L MCFEA TERS HIS A TTORNEVS' March 20, 1962 H. L. MCFEATERS HOOD POST CRANE 16 Sheets-Sheet 14 Filed March 18, 1958 INVENTOR.

f/ARRVL MCFEATERS H/s ATTORNEYS.

March 20, 1962 H. L. MGFEATERS 3,026,102

HOOD POST CRANE Filed March 18, 1958 16 Sheets-Sheet 15 INVENTOR. 644m? Y L Mc F124 TERS il izcm w HIS A77'OR/VE'VS.

March 20, 1962 H. MOFE'ATERS HOOD POST CRANE RN HN United States Patent 6 3,026,102 HGOD POST CRANE Harr y L. Mcl eaters, New Castle, Pa., assignor to Pennsylvania Engineering Corporation, New Castle, Pa., a corporation of Eennsylvania Filed Mar. 18, 1958, Ser. No. 722,257 26 Claims. (Cl. 266-35) This invention pertains to a new and improved operating layout, system or procedure for a converter type of vessel or furnace such as used in refining metal.

A phase of the invention deals with handling equipment to be used with a vessel or converter for refining metal, such as steel, and for facilitating the employment of such a vessel and increasing its efiiciency and effectiveness of operation. Another phase deals with the processing and handling of hot, contaminant-laden discharges from the mouth of a generator to avoid atmospheric contamination and recover metal oxides, etc., that may be carried as fume, as dust particles or as vapor with the discharge. A further phase deals with apparatus for improving the operation of a converter from the standpoint of the aspiration or air during the melting or refining operation.

As pointed out in my Patent No. 2,803,450, it is important to avoid the direct discharge of fumes, flame and gas from a mouth of a vessel directly into the atmosphere, both from a standpoint of the well being or" the community and from the standpoint of minimizing airplane spotting by night. The problem has become particularly important in view of the increased acceptance of the socalled oxygen (LP) blow type of refining operation. Also, in such a type of operation, problems have arisen in connection with the employment of an overhead-introduced oxygen blow lance, its positioning and withdrawal, and in connection with the charging and pouring of the vessel, and with further charging during the melting operation, such as with slag-forming materials including lime, mill scale, etc.

In providing a suitable apparatus and layout to meet the needs of such an installation and provide a solution to the many problems involved, the factor or" space limitations has to be considered. In other words, I have found that the installation should be such that it can be adapted to conventional mill space that may be available for conventional mill installations which include overhead cranes. I have been able to develop a construction and layout which can be installed for efiicient operation of one or more melting or converter vessels in substantially the same space that has heretofore been allocated for open hearth and electric furnace installations. Because of the need for raising and lowering a hood that is employed to collect the discharge from each vessel and for handling the oxygen lance, the factor of head room space is particularly important.

it should be noted that the discharge from a vessel, such as an oxygen blow vessel or converter, may be within a temperature range in the neighborhood of about 3,000 to 3,l F. and particularly so, in connection with larger size vessels of, for example, 80 tons capacity or more. Thus, the apparatus employed should not only be able to withstand such temperatures with minimum maintenance, but should be capable of doing so without danger of explosions, and in such a manner as to fully take care of the large volume of the discharge, particularly during the blowing operation, and in such a manner, that refining of the metal may be accomplished with full and maximum efiiciency.

l have determined that overshadowing all the problems and factors involved is the need for suitable supporting and handling apparatus, not only for the hood, but also for the oxygen lance. It should be flexible from the standpoint of individual reuuired operations as to the hood ice and lance and as to the conve ter, itself, and in such a manner that the lance may be cleaned and, if necessary, replaced as the need may arise. Although lances are water-cooled and when properly constructed will last for about to heats without cleaning, I have found that they Will last for about 1,000 heats when periodically cleaned. Atmospheric air normally contains about 79% nitrogan, and the velocity of flow of an oxygen blow tends to aspirate the atmospheric gases into the mouth of the vessel. Thus, a much better refined product, closely approaching in quality that of the open hearth steel, may be attained by substantially eliminating the sucking-in of atmospheric gases.

In general, I have devised apparatus and an apparatus layout or system that meets the many factors and problems presented in this connection, that does so in a practical and eificient manner, and that permits any desired usage of the converter vessel, including the additions of clean scrap metal and of slag forming materials, and a proper charging and pouring of the vessel.

It has thus been an object of my invention to meet the factors and solve the problems involved and to provide improved apparatus for cooperative use with a metal melting, refining vessel or converter;

Another object is to provide a system which will assure a new and improved operative cooperation and functioning' between a vessel, a hood and a lance;

Another object has been to provide a commercially practical embodiment of my inventive discoveries;

A further object has been to improve and facilitate the operation and the resultant product produced by a converter melting type of metal refining or conditioning process;

A still further object has been to provide improved apparatus for receiving, controlling and processing the discharge from a converter vessel and for controlling and facilitating its operation;

These and other objects of my invention will appear to those skilled in' the art from my description of the illustrated embodiment thereof;

In the drawings, FIGURES 1a, 1b and 1c are plan views of a layout or system constructed and employed in accordance with my invention wherein centrally-disposed, slag-material-handling apparatus (see FIGURE 1b) is employed with a pair of converter vessels and their attendant lance and hood apparatus;

More specifically, FIGURE 14 is a layout of a left hand converter system, FIGURE 1b is a plan of the centrally-disposed material-handling system, and FIG- URE 1c is a plan of a right hand converter system that is similar in construction, apparatus and operation to the system of FIGURE 1a;

FIGURE 2 is an end view in elevation on the scale of FIGURES 1a, 1b and 1c, showing a converter vessel in vertical operating position and its relationship with spark trap apparatus; a hood is shown in a raised and out-swung position with respect to the converter and the spark trap apparatus;

FIGURE 2a is a greatly enlarged sectional detail through the wall of spark trap apparatus, such as illustrated in FIGURE 22, and showing a typical mounted relationship of cooling-fluid or water-spray means;

FIGURE 3a is a front or side view in elevation of the converter vessel, hood, spark trap apparatus, and of a ladle car of and on the same scale as FIGURE 1a; it will be noted that the apparatus of 1c is of the same construction as the apparatus of FIGURE la and thus, that FIGURE 3a is also representative of the apparatus of FIGURE 10, except that it is turned FIGURE 3b is a side or front view in elevation on the same scale as and taken along the line IIIbIIIb of FIGURE 1b;

FIGURE 4 is a view in elevation, taken along the line IVIV of FIGURE la, and on the same scale as that figure; it particularly illustrates mast, jib and swing frame features of post crane apparatus employed in accordance with my invention; this view shows the general arrangement of the post mechanism;

FIGURE 5 is an enlarged horizontal section taken along the line V-V of FIGURE 4, through the post crane apparatus;

FIGURE 6 is a fragmental section in elevation on the scale of and taken along the line IV-IV of FIGURE 5;

FIGURE 7 is a plan detail of a swing arm or frame jib of a hood part of the post crane apparatus and on a slightly enlarged scale with respect to FIGURE la;

FIGURE 8 is a vertical fragmental view on the scale of FIGURE 7 and showing outer portions of the hood jib of FIGURE 4, and particularly showing a swing jib hoist employed to change lances;

FIGURE 9 is a vertical view in elevation and partial section on the scale of FIGURES 7 and 8 and showing details of the construction of operating means for raising and lowering the hood frame;

FIGURE 10 is a somewhat diagrammatic or schematic view in elevation showing support and hoisting means for a lance crane or jib of the post crane apparatus and on the scale of FIGURES 1a, 1b, 1c and 4;

FIGURE 11 is an enlarged fragmental horizontal section, taken along the line XIXI of FIGURE 10;

FIGURE 12 is a fragmental vertical view on the scale of FIGURE 11 and taken at right angles to FIGURES 10 and 11;

FIGURE 13 is a fragmental horizontal section on the scale of FIGURES 11 and 12 and taken along the line )GIIXIII of FIGURE 12;

FIGURE 14 is an enlarged fragmental plan, partially in section, illustrating details of a pair of lance clamping means of which the left hand one of this figure is carried by the hood jib and its swing arm, and the right hand one is carried by a fixed part of the post crane that projects outwardly as an arm or jib from the central part of the post crane apparatus;

FIGURE 15 is a side view in elevation and partial section of the structure of and on the same scale as FIG- URE 14;

FIGURE 16 is an enlarged plan view, partially in section, showing quick-coupling top connections to a head or closing cap part of the lance, whereby oxygen may be supplied centrally thereto, cooling fluid may be supplied thereto about the oXygen-carrying portion, and heated fluid may be removed therefrom;

FIGURE 17 is a side view in elevation and partial section on the same scale as and showing the structure of FIGURE 16;

FIGURE 18 is an enlarged side view in elevation and partial section, showing a converter vessel and its hood in a sealed or operating position with respect to each other, and illustrating details of the construction of the hood and of duct means for delivering additions, such as slag-forming materials, through the hood to the converter;

FIGURE 19 is a greatly enlarged fragmental plan view of a self-centering, sealing-off or lance gate means that is mounted on the hood to close or seal-0E a lance opening in the upper portion of the hood when the lance is in an operating position with respect to the converter vessel; this figure is enlarged with respect to FIGURE 18;

FIGURE 20 is a view similar to FIGURE 19, but showing the gate means in a closed or sealed relationship about the lance, whereas FIGURE 19 shows it in an open relation, such that the lance top or head part may be lowered or raised through the hood;

FIGURE 21 is a vertical view in partial section and on the same scale as and of the apparatus of FIGURE 20 and taken along the line XXIXXI of FIGURE 20;

FIGURE 22 is a vertical view in elevation and partial section, on the scale of FIGURE 3a, showing the operating relationship between a converter, its hood and spark trap apparatus, including exhaust piping; the spark trap apparatus, its construction, as well as its sludge collecting means are illustrated in detail;

FIGURE 23 is an elevation in partial section on the same scale as and of the apparatus of and taken along the line XXIIIXXIII of FIGURE 22;

FIGURE 24 is a vertical view in elevation and partial section through a converter, such as shown in FIGURES 1a and 10, which is adapted for utilization with the hood and other apparatus shown; this view is on a scale intermediate between FIGURES la and 18;

FIGURE 25 is a view in elevation taken at'right angles to and on the same scale as the vessel of FIGURE 24;

FIGURE 26 is a top plan view of and on-the same scale as the vessel of FIGURE 24;

And FIGURE 27 is a somewhat diagrammatic layout illustrating operating connections for cooling fluid, such as water, for oxygen supply "to the lance, and for pneumatic or pressure fluid to operate air motors or cylinders; this view also illustrates a so-called sight gravity feed or drain of heated water or fluid that is returned centrally along the post crane apparatus to the sewer or to a fluid reconditioning system.

The Operating Layout Referring particularly to FIGURES 1a, 1b and 10, I have shown a two unit converter installation or layout employing the principles of my invention. The converter vessels or metal-refining units A and their attendant apparatus are shown located at opposite ends of a centrally-disposed additive supply system that includes a car dump track hopper, grating unit or storage area 0, and an additive-supply weighing and distribution unit or structure P. The unit P includes conveyors, elevators, weighing and discharge hoppers which may be employed for supplying additives, such as mill scale and lime, to oppositely-disposed endwise-moving conveyors, one of which 225 supplies additives to the left hand converter and the other of which 213 supplies them to the right hand converter. Both of the converter vessels are of the same construction and are designated as A.

- Referring particularly to FIGURES la, is and 2, a post crane apparatus, structure or unit, designated as B, is 0peratively mounted for movement between an out position I and an in or converter vessel cooperating position 11. As shown particularly in FIGURES 3a, 4 and 18, an inlet sealing ring or portion 114 of enclosing walls of a hood unit D is adapted to make a sealing fit with a top lip or sealing edge 21a of a mouth portion of the converter A when the post crane apparatus B is at position II. It will be noted that the hood D provides a fume discharge-receiving cover for the vessel A. At the same time, an outlet sealing flange portion 119 (see FIGURES 2, 3a, 18 and 22) of the converter A makes a sealing abutment with an inlet sealing face flange portion 141 of a fume processing receiver or spark trap apparatus G. It will be noted that the hood D (see FIGURE 3a) is shown of relatively short length to provide a direct flow path between the vessel A and receiver G. The inlet and outlet portions of the hood D are also shown at right angles to each other, as are the mouth portion of the vessel A and the inlet portion of the receiver G. Further, the bottom of the inlet portion of the receiver G is shown in substantial alignment with the top or lip of the mouth portion of the receiver A. As shown, the hood D provides a direct connection between the furnace vessel A and the fume processing receiver G, is of an integral, nonpartible, tubular, dual shell wall construction, is positioned for movement into a cooperating fluid-sealing-ofl relation between the vessel A and the receiver G and for movement out of such relation to permit the vessel to be charged, tilted, repaired, etc. As shown in FIGURE 4, the hood is flexibly suspended by chains or cables in such a a manner as to center itself into, seek and find an effective seating relation between the receiver G and the vessel A and particularly, on the sealing edge 21:: of the vessel when the sealing ring 114 of the hood is lowered into a cooperating relation therewith. This eliminates the need for a sectioned, refractory-lined, intermediate connection collar between a vessel and its hood and whose sections are partible and swing horizontally-outwardly therebetween.

Flame, fume, smoke, vapors, etc., are directly dischmged into the hood D and are subjected to cooling water spray jets of suflicient intensity or force to provide a wall-screening curtain of fluid along the inner surface of the hood D to protect it and to condition and cooldown the fume or discharge from an entering temperature of about 3000 to 3100 F. to a temperature of discharge from the hood of about 2500 F. The intensity pressure of the spray from the jets is at least sh'ghtly greater than the force or pressure of movement of the fume through the hood D as, for example, effected or at least partially induced by an exhaust fan (not shown) may be located within or in connection with an exhaust conduit 148 that leads from spark trap or fume receiving and processing apparatus G.

For an installation employing about 80 ton net converters, I have successfully used spray nozzles with about a inch opening and which have about a 12 inch peripheral or circumferential spacing along the inside of the hood D. Such nozzles will provide jets that are of suflicient velocity to cut through the gases or fumes when the sprays are projected at about 120 pounds per square inch. The jet sprays not only protect the inner wall of the hood, but help to immediately solidify slag and other vaporized solids.

As shown in FIGURES 22 and 23, the discharge or outflow of fume from the hood D is flowed into the spark trap apparatus G where it is subjected to additional cooling and conditioning action. As shown particularly in F1- URES 2a and 22, cooling fluid jets in the refractory wall of the spark trap apparatus G spray water or cooling fluid in a substantial mist form as the furne or discharge moves therethrough. Sludge and condensed particles from the fume or discharge are collected at the bottom of the spark trap, while the now-cooled and treated gases are discharged therefrom at a temperature of about 500 F. into the down or discharge conduit 148 which may carry them to a final conditioning apparatus (not shown), but such as indicated in my Patent No. 2,803,450.

Referring again to FIGURES 1a and 1c, charging metal may be supplied to each converter A by tilting it on its side and employing a charging ladle car K which moves on side tracks I On the other hand, slag may be removed from each converter by slag cars M and refined metal by ladle cars N which operate on opposite side tracks L. It will be noted that each converter A is mounted for tilting in opposite directions, so that it can be easily charged, poured or tapped.

Referring particularly to FIGURES 1a, 3a, 4 and 18, the hood D is shown provided with a top opening through which a suitable oxygen or blow lance E may project, and also through which it may be raised and lowered to, as shown in FIGURES 1a, and 2, drop it in a lance pit Q, at which it may be cleaned or reconditioned. At the same time, a substitute lance E may be picked-up for use. Although in FIGURES la and lo, I have shown only one lance pit Q, it will be apparent that any number may be provided, as needed. In this way, lances can be periodically cleaned and reused until they are worn out, at which time, they may be removed from the pit by an overhead crane and a new lance substituted.

The post crane apparatus B has, as shown, out-swing arm, frame or jib means, generally designated as C, which is moved about the central post of the apparatus B to swing it between the previously mentioned positions I and II. T he swing arm means comprises a swing arm or jib frame 76 for raising and lowering the lance E into and out of an operating position within the converter A (see FIGURE 4). It will be noted from FIGURES 3a and 4, that in its upper position, the lance E clears the mouth and lip of the converter A and its lower end portions lie within the hood D. In its lower position, the end portion of the lance E is located at a suitable level with respect to the melt line, for example, with an 18 inch spacing that is suitable for the refining operation. In FIG- URE 4, I have shown a scale R for indicating the positioning of the inner end portion of the lance E within the mouth of the converter to visually indicate it for reference and control purposes.

The swing arm means C also comprises a swing arm or jib frame beam structure 52 of fixed vertical mounting with respect to the apparatus B that carries a swing jib or auxiliary hoist 167 for handling the lance E when it is to be lowered through the hood D into a pit, such as Q. The hoist 167' is also used when a new or replacement lance E is to be lifted out of a pit Q, to be carried up into the hood D, and then to a position above the converter A. A hood frame structure 56 carries the hood D and 'moves with it as an integral part thereof when the hood is raised into and out of a sealed or cooperating relationship with the upper lip edge of the converter A, and swung into and out of position with the inlet flange of the spark trap G. When raised, the hood D is free to be swung on its beam jib structure 52 out of a cooperating and sealing relationship with the entry or inlet end of the spark trap G, and to be carried with the lance E from position II to position I of FIGURES 1a and 2. g

It should be noted that service utilities, such as water, oxygen, air, electric wiring, etc., are positioned to extend along a hollow center post or axis of rotation of the post crane apparatus B and along, see also FIGURE 27, easily disconnecting swing joints, so that the apparatus including lmce E, may be readily connected and disconnected for maintenance and repair. In addition, flexible expansion joints are provided to permit necessary raising and lowering movements and in this connection, flexible hose may also be employed. The swing joints may be of conventional construction, such as supplied under the trademark Barco.

It will be noted that, in accordance with my invention, the converters A are blown by means of the lances E with the hoods D tightly in place, not only with the converters A, but with respect to the spark traps G. This, with a self-centering, sealing or closing olf lance gate means 125, 126 shown in FIGURES 18, and 19 to 21, substantially eliminates aspiration of atmospheric air and nitrogen of the air during the refining operation. The construction and mounting of the hood D with respect to each converter A is such that the hood, in effect, constitutes a top for the converter. Thus, some vaporized metal oxides, etc., may be condensed and returned to and carbon monoxide gas burned to carbon dioxide in the converter for minimizing the loss of value content of the melt and of the heating content of the gases. It will also be noted that the hood D has a short and abrupt-turn right-angle side outlet which further minimizes losses.

FIGURE 18 shows duct means F for supplying the additives, such as lime and mfll scale, through the hood D to the converter A at any time while the hood is in place over the converter. As previously pointed out, such additives may be supplied by unit P.

The raising and lowering of the swing jib 76 for the lance E may be constructed to provide approximately 15 feet lift or movement of the lance. The raising and lowering of the swing jib for the hood may be constructed to provide a lesser movement of about 18 to 24 inches.

As shown in FIGURES 5, 6 and 9, I have provided three drive means for the post crane B, one 35 for rotating it as a unit along with its jib means C, a second 5 for raising and lowering the lance jib, and a third 73 for raising and lowering the hood jib. For simplicity, electrical motors have been utilized in this connection.

The lance E is provided with two sets or pairs of clamping means. An upper pair or set is actuated by fiuid motor 188 (see FIGUES 14 and 15), and is carried by the lance jib 76 (see FIGURE 4) to normally grip the lance at all times when the lance is being raised and lowered by the lance jib, and except when it is to be replaced by means of the auxiliary hoist 167. A second set or pair of clamps is mounted on the vertically-fixed jib 52 of the jib means C and is actuated by fluid motor 177 (see FIGURE 14) to grip the lance below the firstmentioned set of clamps when the lance is in its lowered position within the converter and again to aid in support ing it and to prevent pivot action when the lance is raised to its uppermost position of FIGURE 4.

Structural Details As shown particularly in FIGURES 2, 3a, 4 and 5, the floor level of the mill has been designated as 10. Beamsupported, removable grating 10', on the same level as the floor 10, is shown in FIGURE 3a to provide easy access to operating parts of the converter A. As shown in FIGURE 2, the lance pit Q is provided by an opening in the floor 10 that is carried on an under pit floor 9 by upright support members 11. The converter A is shown mounted, at least as to its trunnion and operating means, below the floor level on a base 12 which carries a pair of transversely spaced-apart trunnion stands 13 and their associate trunnion bearings, see particularly FIG- URES 2 and 3a.

The vessel A has, as shown in FIGURES 3 and 24, central pinion or trunnion end shafts 14 and 14a. One shaft 14a serves as the drive through a speed reducing, intermeshing gear train or unit 15. The larger gear of the gear unit'15 is keyed to the shaft portion 14a and the other or smaller gear is keyed to a conventional reversible motor drive unit 16, in order that the converter may be tilted or revolved to present its mouth portion at any suitable position for charging and discharging it.

As shown in FIGURES 24 to 26, the converter A has an inner refractory lining of rounded convolute shape to correspond to the shape of the normal wear and thus, minimize such wear particularly, during the blowing operation. The inner refractory wall 18 terminates at its upper end in a substantially vertical pour lip or mouth portion 180. The refractory wall is of substantially the same thickness along its extent, with a slight Widening from its melt line to further increase its wear resistance. An outer metal shell or casing 19 encloses the refractory wall 18 and is reinforced by an outer frame 20 to carry the end shafts 14 and 14a.

At its mouth or upper end, the vessel or converter A has a separate reinforcing framework 21 which carries an inwardly-upwardly declining metal sealing rim or lip portion 21a. As shown particularly in FIGURE 18, it is this portion which is engaged by the sealing ring portion 114 of the hood D to provide a sealing fit with respect thereto at the time of the refining operation and of fume discharge. As shown in FIGURE 25, the converter vessel may be provided with a tap open portion 22 in its metal casing and a corresponding through open portion 18b in its refractory wall. A conventional tap hole plug (not shown) may be employed to close off the tap hole thus provided.

In FIGURES 2, 4, and 6, I have illustrated how the post crane B is securely bolted to the floor 10. In FIG- URE 6, it will be noted that the floor has suitable openings therethrough to bypass cooling water, operating air, oxygen and electrical connections. The bottom of the hoist crane B has a fixed-position or under-support frame, stand or table 25 that extends therebeneath and carries a top or ring gear and track supporting plate 26. An

upwardly-projecting bull wheel or annular ring member 2'7 is secured to project upwardly from the plate 26 and has outwardly-beveled inner ring gear or annular rack portion 27:: to mesh with a beveled drive gear, pinion or whcelZS and rotate the post crane about its central axis.

A drive shaft 29 on which the drive gear or pinion 28 is secured is carried by bearings 39 at its ends which are suspended from an upper rotatable support frame or table structure 31. A side housing skirt or plate 32 projects downwardly from the upper support frame 31, as also disclosed in FIGURE 6. The drive shaft 29 has a drive Wheel gear train 33 which is actuated through speed reducer 36 (see FIGURE 5) by a reversible electric motor 35. The beveled gear 28 is thus driven at a relatively slow speed to advance it along the teeth of the ring gear portion 27a and effect rotation of the upper frame structure 31 about the lower or stationary frame structure 26. As shown particularly in FIGURE 5, a magnetic brake 35a is provided for controlling the operation of the motor 35.

As shown in FIGURES 5 and 6, the upper frame or table structure 31 also rotatably journals or carries a pair of beveled guide roller wheels 38 that are mounted to project downwardly therefrom at an outer position with respect to the beveled drive wheel 25. The rollers 38 engage and move along an outer outwardly-declining track or rail portion 27b of the annular ring member 27 for rotative movement therealong during the rotation of the upper table 31.

The central portions of the stationary table 25 and the rotatable table 31 are open vertically to receive a hollow central tube or post member 46, along which electrical wiring, etc, are adapted to extend. The tube 40 at its upper end carries an enlarged collar 41 whose lower flange portion 41a is provided with pins 42. The limits of crane rotation may be controlled by manual switches or by conventional electric limit switches for the driving motor. As shown particularly in FIGURES 5 and 6, the pins 42 are adapted to drop into one of several cross slots 37a in a disc ring 37 that is secured to the top of the table 31 to prevent rotation of bearing housing with respect to the post crane deck. An enlarged shaft portion 43 is secured to the collar 41 and about the central post or tube 49 and has bearing portions 43a to engage upon an inner bearing wall portion 31a of the rotating table 31.

The enlarged bearing shaft portion 43 terminates in a reduced lower shaft portion 44 which is engaged at its upper and lower end portions by spaced-apart guide and bearing rings 39 that are carried by an inner wall portion 25a of the bottom or stationary frame structure 25. A washer ring 45 and end positioning nut 46 are carried on a lowermost portion of center post or tube 40 to seal ofi the above positioned bearings and hold the shaft construction in position in a fixed relationship as to the bottom frame structure 25.

Four substantially equally-peripherally spaced-apart upright channel-shaped support members 50 are secured at their bottoms to project upwardly from the upper or rotating table or frame structure 31, as shown particularly in FIGURES 5 and 6 of the drawings. A ladder 5%, see FIGURE 4, may be secured in position along one of the upright beams or channels 5! to facilitate inspection and repair of the apparatus.

The upright support members 59 are reinforced by cross frame beams 51 substantially intermediate or midway of their lengths, and at their upper end portions, by inner portions of channel frame 52 constitute the fixed jib or outwardly-projecting support arm structure. The structure provided by 52 has a fixed vertical positioning, but will swing or turn with the upper table 31. As shown in FIGURE 4, the vertically-fixed jib frame or support arm structure 52 has side rails 520, so that an operator may walk tilerealon g. The fixed jib or support arm structure 52 is shown reinforced by side bracket members 53 (see FIGURES 2 and 4) which are secured at their one ends to the bottom of the fixed jib 52 and at their other ends to the upright members 50.

As shown in FIGURES 2, 3a, 4 and 8, the hood D, in effect, provides one hoist jib of the post crane, sinceit is provided with upwardly-projecting lugs 58 that project from its frame 56, see also FIGURE 18. The lugs 58