US3348833A

US3348833A - Deskulling apparatus

Info

Publication number: US3348833A
Application number: US417135A
Authority: US
Inventors: Herbert A Long; William E Brown; Laddie J Crincic
Original assignee: Blaw Knox Co
Current assignee: Blaw Knox Co
Priority date: 1964-12-09
Filing date: 1964-12-09
Publication date: 1967-10-24
Anticipated expiration: 1984-10-24

Description

Oct. 24, 1967 H. A. LONG ETAL 3,348,833

DESKULLING APPARATUS Filed Dec. 9, 1964 5 Sheets-Sheet 1 & m I w o v t N we l K I 51 F 1 Q m I l R INVENTORS. HERBERT A. 1.0/10

WILL/AM E. BROWN 4400/5 J. cex/vc/c 5 mgiwagw M1m ATTOR/VEVS.

Oct. 24, 1967 H. A. LONG ETAL 3,348,833

7 I DESKULLING APPARATUS Filed Dec. 9, 1964 5 Sheets-Sheet 5 INVENTORS. HERBERT A. LONG W/LL/AM E. BROWN BY LADD/E J. (RM/67C AUDRNEVS'.

DESKULLING APPARATUS 5 Sheets-Sheet 4 Filed Dec. 9, 1964 ATTORNEVJ.

United States Patent 3,348,833 DESKULLING APPARATUS Herbert A. Long, Belle Vernon, William E. Brown, Centerville, Pa., and Laddie J. Crincic, Belle Vernon, Pa.,

assignors, by mesne assignments, to Blaw-Knox Company, Pittsburgh, Pa., a corporation of Delaware Filed Dec. 9, 1964, Ser. No. 417,135 11 Claims. (Cl. 26636) ABSTRACT OF THE DISCLOSURE Apparatus for deskulling a tiltable steel-making vessel has upwardly directed deskulling teeth supported by a frame pivotally mounted on a horizontal axis. The frame normally holds the teeth in a position to be engaged by the skull projecting from the vessel when the latter is tilted toward the teeth, but the frame will yield Whenever the pressure of the skull against the teeth exceeds a predetermined value.

In the basic oxygen furnace system of making steel, fuel is not used. Instead, a vessel is charged through its open top with scrap, supplemented with hot metal from a blast furnace. After the required fluxes have been added, a jet of practically pure oxygen is directed into the molten metal through a water-cooled oxygen lance. The required conversion temperatures are developed from the exothermic reactions of oxidation of carbon, silicon and phosphorus resulting from the forced introduction of the oxygen. These reactions produce the steeel during the blow. Following refinement of the furnace charge into steel in this manner, the vessel is tilted to pour its molten contents out of its open top. During pouring, a skull of slag is formed around the vessel opening. This skull continues to build up and obstruct the opening, so it must be removed periodically. Various means have been proposed for breaking away the skull, i.e. deskulling the vessel, but all of them leave much to be desired. One serious difficulty has been that the vessels drive, motor and supporting structure are damaged during the deskulling operation, due to the skull striking the deskuller with too much force.

It is among the objects of this invention to provide deskulling apparatus which is safe to use, which operates automatically, which adapts itself to the conditions under which it is operating at any given time, and which is easy to maintain in satisfactoryoperating condition.

In accordance with this invention, the deskulling apparatus has a frame that is pivotally supported on a horizontal axis beside a tiltable steel-making vessel that is to be deskulled. The frame supports a plurality of upwardly directed deskulling teeth in front of its pivotal axis in a row extending lengthwise of it. Preferably, each tooth is provided with a cap that can easily be replaced when worn. The frame is normally held in a position where the teeth will be engaged by the skull projecting from the lip of the vessel in front of the frame when the vessel is tilted toward the teeth. The frame-holding means is adapted to yield whenever the pressure of the skull against the teeth exceeds a predetermined value,

whereby to allow the teeth to be forced downwardly a predetermined distance. Preferably, from any point within that distance the teeth are raised to their normal position automatically when the skull pressure is removed. However, if the skull attempts to force the teeth down beyond that predetermined distance, the rotation of the vessel is stopped and the frame may be positively rotated to lower the teeth away from the skull to avoid damage.

Patented Oct. 24, 1967 FIG. 2;

FIG. 4 is an exploded front view of one of the deskuller teeth;

FIGS. 5 and 6 are exploded side and rear views, respectively, of the tooth;

FIG. 7 is a plan view, partly in section, of one of the fluid pressure cylinders; and

FIG. 8 is a diagram of the hydraulic system that operates the deskuller.

Referring to the drawings, a typical oxygen converter vessel 1, such as used for making steel in the basic oxygen furnace system, is rigidly mounted in a normally horizontal ring 2 that is provided with trunnions 3 that support it in bearings 4. The vessel normally is positioned with its open end up. The vessel is surrounded by a working-floor 6, directly below which at one side of the vessel the deskulling apparatus is mounted. This apparatus or deskuller includes a large horizontal shaft 7 that is parallel to the axis on which the vessel tilts. One end of the shaft is journaled in a gimbal 8 pivotally mounted on a horizontal axis between supports 9 suspended from a beam 10 beneath the floor. The other end of the shaft is journaled in a bearing 11 supported in a similar manner. The shaft also is slidable axially in this bearing to allow for thermal expansion.

On the central portion of shaft 7 a deskuller frame is rigidly mounted. Preferably, the frame is rectangular and normally horizontal. It may be made from two parallel end members 13 through which the shaft extends, a cylindrical front member 14 rigidly connected to one of the end members and slidably connected to the other,

and a back member 15 connecting the rear ends of the end members. The back member is heavy and serves as a counterweight. Rigidly mounted on the front member of the frame is a row of deskulling teeth 16 which extend upwardly from it. As shown in FIG. 2, the upper front edges of the teeth are arranged in the general form of an arc and in such location that when the vessel is tilted toward them its lip will clear the teeth as shown in FIG. 3, but any appreciable build-up of skull around the lip will strike the teeth.

To enable the teeth to be repaired or replaced readily, it is preferred to construct each tooth from two parts, a cap 18 and an upstanding body 19 supporting the cap, each being formed from plates and bars welded together. The lower ends of the tooth bodies surround the front member of the frame and taper upwardly and slightly forward from it as shown in FIGS. 1, 3 and 5. Each tooth cap is provided with a downwardly opening socket 20 of a shape to receive and rather loosely fit the upper portion of a tooth body in order that the two members can be connected together as a unit. The front wall of the cap is substantially vertical, but its top is inclined rearwardly and upwardly from the front of the cap.

In order to control the position of the deskuller frame, a pair of arms 22 are rigidly connected to shaft 7 near its opposite ends. Preferably, the arms extend downwardly nearly vertically from the shaft while the frame is horizontal. The lower end of each arm is pivotally connected to the front end of a piston rod 23 that extends back into a fluid pressure cylinder 24. As best shown in FIG. 7, the rear end of the cylinder is mounted in a head 25, from which project integral

hollow trunnions

26 and 27 that extend through bearings 28 rigidly supported by suitable supports beneath the floor. The outer ends of draulic system that operates the deskuller. The inner end of trunnion 26 communicates inside the block with the rear end of a pipe 29 that extends along the outside of the cylinder to its front end. The inner end of the other trunnion opens into the rear end of the cylinder behind the piston 30.

The fluid pressure delivered to the opposite ends of the cylinder normally is the same, but due to the area of the front of the piston being reduced by the piston rod, the pressure against the back of the piston is greater and therefore the piston normally is held at the front end of the cylinder to hold the deskuller frame in horizontal position. Whenever the pressure behind the piston is reduced sufficiently, the greater pressure in front of the piston will force it back in the cylinder and the frame will be tilted to swing the teeth 16 downward as shown in dotted lines in FIG. 3.

This apparatus also is provided with limitswitches for a purpose to be described presently, which are operated as the frame tilts. Preferably, a pair of

limit switches

32 and 33 are mounted on a channel 34 extending lengthwise of each cylinder and attached thereto. A switchactuating bar 35 is disposed in each channel and is connected at its front end to the front end of the piston rod. As the bar is moved back and forth in the channel 'by the piston rod,v it will actuate the limit switches.

The hydraulic system which operates the deskuller is illustrated diagrammatically in FIG. 8. It includes a tank 36,.from which hydraulic fluid is pumped by a pair of pumps 37 driven by a motor 38, and to which the fluidis returned. The inlets of the pumps are connected by pipes 39 to the tank, while their outlets are connected through check valves 41 to a common pipe 42 that is connected by a delivery pipe 43 to a solenoidoperated pilot controlled directional valve 44. While in one position, this valve connects the delivery pipe with a check valve 46 that is provided with solenoid-operated pilot controlled means 47 energized by limit switch 33 for opening the valve under certain conditions to allow reverse flow through it. The outlet of this check valve is connected with a common pipe 48 that delivers the fluid to the hollow trunnions 27 connected with the rear ends of the two cylinders. Pipe 48 also is connected through pipes 49 with adjustable relief valves 50, the outlets of which are connected through pipes 51 and much lower pressure relief valves 52 with the tank.

Common pipe 42 also is connected by pipes 54 with the hollow trunnions 26 that communicate through pipes 29 with the front or rod ends of the cylinders. Pipes 54 also are connected by electrically adjustable relief valves 55, controlled by limit switches 32, with the tank. There also is a check valve 56 between each pipe 54 and the adjacent pipe 51 for a purpose that will be explained later.

When the directional valve 44 is shifted to its opposite position, it closes delivery pipe 43 and connects the reversible check valve 46 with a relief valve 58 in a pipe 59 leading back to the tank. Valve 58 opens at a pressure just high enough to maintain sufficient fluid pressure in the system to operate the necessary controls.

Assuming that the deskuller teeth are in their lowest position, this apparatus is set in operation by closing a switch in a suitable electric circuit which will energize one of the solenoids connected with the directional valve 44 to cause it to shift from its right-hand position to its left-hand position as shown. Simultaneously, the circuit will start motor 38 to operate the pumps and energize the solenoids that control relief valves 55 to adjust those valves to their high pressure setting so that a high fluid pressure, such as 500 pounds p.s.i., can be built up in the system. Fluid then will be pumped out of the tank and delivered through

pipes

43 and 54 to the opposite ends of cylinders 24. This will cause the pistons 30 to be moved forward to rotate the deskuller frame and 4 thereby swing the teeth up to operating position. As the pistons reach the front ends of the cylinders, limit switches 32 will open to cause relief valves 55 to open at a much lower pressure, such as pounds p.s.i., but the high pressure in the rear or blind ends of the cylinders will be maintainedbecause check valve 46 will prevent flow.

of fluid therefrom back toward the pumps.

The converter vessel then is tilted. over toward the deskuller teeth to strike the skull around the lip of the vessel against them. If that breaks the skull away from the vessel, that is all that is necessary and the vessel then can be returned to upright position. On the other hand, if the skull does not break away upon engagement with the teeth, its downward pressure on the teeth will cause the pivoted frame to force the pistons back against the fluid in the cylinder until the pressure therein builds up sufficiently to open relief valves 50, which are adjustable for opening at any desired pressure above the high setting of relief valves 55,'such as above SOOpounds p.s.i. It has been found suitable to have valves 50 open when the fluid pressure thereon reaches about 1800 p.s.i. Opening of the relief valves 50 will allow the teeth to be pushed down by the skull to prevent breakage of any of the equipment. It will be seen that the maximum resisting force of the deskuller against the skull on the top of the vessel is determined by the setting of relief valves 50. Since the vessel is likely to push the pistons back in the cylinders faster than fluid can be pumped into their front ends, cavitationin the front ends is prevented by fluid being exhausted from relief valves 50. This fluid will flow through check valves 56 and maintain the front ends of the cylinder full.

As soon as the deskuller teeth start to move down, the switch bars 35 close limit switches 32 so that relief valves 55 will be returned to their high pressure setting and high pump pressure again will be available for the rear ends of the cylinders. If the skull breaks away before the teeth have moved down a predetermined short distance, such as 8 or 10 inches for example, the teeth immediately will be swung or bounced back up to their upright position by the high fluid pressure delivered by the pumps behind the pistons.

It may happen, however, that the skull does not break away from the vessel while the teeth are moving down the short distance just mentioned, so to prevent damage and to permit another attempt at breaking the skull the teeth are, pulled downwardly away from the skull. This happens as soon as the switch bars are moved back along the cylinders far enough to close limit switches 33. Through a suitable electrical control circuit, closing of these switches stops the tilting of the vessel and causes the directional valve 44 to shift to the right in order to connect drain pipe 59 with check .valve 46. Limit switches 33 also operate the control means 47 that-causes check valve 46 to open so that there can be reverse flow through it. The fluid pressure behind the pistons thus is connected with drain, so the higher fluid pressure in the front ends of the cylinders moves the pistons rearwardly therein. When the pistons reach their rearmost position in the cylinders, the switch bars 35 close a third set of limit switches 61 attached to channels 34 to turn the pump motor off. The vessel then can be tilted back to upright position and then the deskuller teeth can be swung back up to their operating. position so that the cycle can be repeated.

It will be seen that withthis apparatus deskulling can be effected with small likelihood of either the vessel or the deskulling apparatus being damaged, because as soon as excessive pressure starts to develop between the skull and the deskuller teeth, the teeth first yield downwardly and then, if the pressure is not relieved, they are pulled away from the skull. The construction of the teeth permits them to be maintained in good condition with little effort and expense.

We claim:

1. Apparatus for deskulling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting the frame on .a horizontal axis, a plurality of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, each of said teeth including a tooth body rigidly mounted on the front of the frame and a tooth cap provided with a downwardly opening socket receiving the upper end portion of said body to support the cap, and means connected with the frame and normally holding it in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, said means being adapted to yield whenever the pressure of the skull against the teeth exceeds a predetermined value to allow the teeth to be forced downwardly.

2. Apparatus for deskulling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting the frame on a horizontal axis, a plurality of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, means connected with the frame and normally holding it in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, said means being adapted to yield whenever the pressure of the skull against the teeth exceeds a predetermined value to allow the teeth to be forced downwardly a predetermined distance, said means also being adapted to raise the teeth to their normal position from any point within said distance when said pressureis removed, and means op erative if the skull attempts to force the teeth down more than said predetermined distance for rotating the frame to lower the teeth away from the skull.

3. Apparatus for deskulling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting the frame on a horizontal axis, a plurality of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, an arm having one end connected with the frame for tilting the frame, fluid pressure means operatively connected with the opposite end of the arm for normally holding it and the frame in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, a relief valve connected with said fluid pressure means and adapted to be opened whenever the pressure of the skull against the teeth exceeds a predetermined value to allow them to be forced down, the fluid pressure means being effective to swing said arm to raise the teeth to their normal position from any point above a predetermined point whenever said skull pressure is removed, and means for reversing said fluid pressure means if the skull attempts to force the teeth down past said predetermined point, whereby to tilt the frame in a direction to lower the teeth away from the skull.

4. Apparatus for deskulling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting the frame on a horizontal axis, a plurality of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, an arm having one end connected with the frame for tilting the frame, a hydraulic cylinder and piston connected with the opposite end of the arm, hydraulic pressure fluid in one end of the cylinder normally holding the arm and frame in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, a relief valve having an inlet connected with said one end of the cylinder and adapted to be opened by said pressure fluid whenever the pressure of the skull against the teeth exceeds a predetermined value to allow them to be forced down a predetermined distance, means for replenishing said pressure fluid in said cylinder to raise the teeth to their normal position from any point within said distance when said skull pressure is removed, and means independent of said relief valve for releasing fluid pressure from said one end of the cylinder while fluid pressure is applied to the opposite end of the cylinder if the skull attempts to force the teeth down more than said predetermined distance, whereby to tilt the frame for lowering the teeth away from the skull.

'5. Deskulling apparatus according to claim 4, including a second relief valve that opens at a lower pressure than said first-mentioned relief valve, and means connecting the outlet of said first-mentioned valve with said opposite end of the cylinder and said second relief valve.

6. (Deskulling apparatus according to claim 4, in which said fluid pressure releasing means includes a check valve normally trapping fluid in said one end of the cylinder, and means for opening said check valve to permit reverse flow therethrough when the skull attempts to force said teeth down more than said predetermined distance.

7. Deskulling apparatus according to claim 6, in which said check valve opening means is electrically operated by means including a limit switch that is actuated when said teeth start to move down more than said predetermined distance.

8. Deskulling apparatus according to claim 4, in which said fluid pressure releasing means includes a check valve normally trapping fluid in said one end of the cylinder, a directional valve normally connecting said replenishing means with the check valve, and means for opening said check valve to permit reverse flow therethrough and for shifting said directional valve to disconnect said replenishing means from the check valve and to connect said reverse flow with drain.

9. Apparatus for deskulling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting the frame on a horizontal axis, a plurality of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, an arm having one end connected with the frame for tilting the frame, a hydraulic cylinder and piston connected with the opposite end of the arm in a position to swing the teeth upward when the piston and blind end of the cylinder are forced away from each other, a hydraulic pump having an outlet connected with the opposite ends of said cylinder for normally holding said arm and frame in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, a check valve normally trapping fluid in the blind end of the cylinder, a relief valve connected to the pump outlet adapted to be opened at a predetermined fluid pressure, said relief valve being adjustable to open at a much higher fluid pres-sure, a second relief valve having an inlet connected with the blind end of the cylinder and adapted to be opened by pressure fluid therein whenever the pressure of the skull against the teeth exceeds a predetermined value to allow the teeth to be forced down a predetermined distance, means for adjusting said firstmentioned relief valve to open at said higher pressure when said teeth start to move downward, and means for opening said check valve to permit reverse flow therethrough if the skull attempts to force said teeth down more than said predetermined amount, whereby the frame will be tilted in a direction to lower the teeth from the skull.

10. Apparatus for deskulling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting the frame on a horizontal axis, a plurality of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, an arm having one end connected with the frame for tilting the frame, a hydraulic cylinder and piston connected with the opposite end of the arm, means for delivering equal fiuid pressure to both ends of the cylinder so that the piston is moved toward the rod end of the cylinder to hold said arm and frame in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, a check valve normally preventing flow of fluid from the blind end of the cylinder back toward said source, a relief valve having an inlet connected with the blind end of the cylinder an'dadapted to be opened by fluid pressure therein whenever the pressure of the skull against said teeth pushes the piston to-- ward the blind end of the cylinder with sufficient force, and means for opening said check valve to permit reverse flow therethrough if the piston is forced more than a predetermined distance toward the blind'end of the cylinder, whereby the fluid pressure in the rod end of the cylinder will move the piston closer to said blind end to tilt the frame in a direction thattwill lower the teeth from the skull.

11. Apparatus for desku'lling a tiltable steel-making vessel used in a basic oxygen furnace system, said apparatus comprising a frame, means pivotally supporting '8 the frame on a horizontal axis, a plurality ,of upwardly directed deskulling teeth supported by the frame in front of said axis in a row extending lengthwise of it, each of said teeth including an upright front plate and a top plate joined at its upper end to the upper end of the front plate, and means connected with the frame and normally holding it in a position where said teeth will be engaged by the skull projecting from the lip of a vessel in front of the frame when the vessel is tilted toward the teeth, said means being adapted to yield whenever the pressure of the skull against the teeth exceeds a predetermined value to allow the teeth to be forced downwardly.

References Cited UNITED STATES PATENTS 1,783,373 1 12/1920 BOI'tOn 241 239 'X' 2,297,604 9/1942 Baternan et al. s 241-239 3,197,187 7/1965 Lakin et al. 26636 FOREIGN PATENTS 1,358,565 4/1964 France.

I. SPENCER OVERHOLS'ER, Primary Examiner. WILLIAM J. STEPHENSON, Examiner.

E. MAR, Assistant Examiner.

Claims

1. APPARATUS FOR DESKULLING A TILTABLE STEEL-MAKING VESSEL USED IN A BASIC OXYGEN FURNACE SYSTEM, AND APPARATUS COMPRISING A FRAME, MEANS PIVOTALLY SUPPORTING THE FRAME ON A HORIZONTAL AXIS, A PLURALITY OF UPWARDLY DIRECTED DESKULLING TEETH SUPPORTED BY THE FRAME IN FRONT OF SAID AXIS IN A ROW EXTENDING LENGTHWISE OF IT, EACH OF SAID TEETH INCLUDING A TOOGH BODY RIGIDLY MOUNTED ON THE FRONT OF THE FRAME AND A TOOTH CAP PROVIDED WITH A DOWNWARDLY OPENING SOCKET RECEIVING THE UPPER END PORTION OF SAID BODY TO SUPPORT THE CAP, AND MEANS CONNECTED WITH THE FRAME AND NORMALLY HOLDING IT IN A POSITION WHERE SAID TEETH WILL BE ENGAGED BY THE SKULL PROJECTING FROM THE LIP OF A VESSEL IN FRONT OF THE FRAME WHEN THE VESSEL IS TILTED TOWARD THE TEETH, SAID MEANS BEING ADAPTED TO YIELD WHENEVER THE PRESSURE OF THE SKULL AGAINST THE TEETH EXCEEDS A PREDETERMINED VALUE TO ALLOW THE TEETH TO BE FORCED DOWNWARDLY.