US1928710A - Method and apparatus for controlling the movement of counterbalanced structures - Google Patents

Description

1933. L. H. UNDERWOOD METHOD AND APPARATUS FOR CONTROLLING THE MOVEMENT OF COUNTERBALANCED STRUCTURES Filed Jan. 17,

INVENTOR Patented Oct. 3, 1933 UNITED$TATE$ 1 "VMETHOD. AND APPARATUS FOR CONTROL- 1 LING THE MOVEMENT moco STRUCTURES OF COUNTERBAL- Lawrence .H. Underwood, Gary, Ind.,' assignor to The Youngstown Sheet and Tube Company, Youngstown, Ohio, a corporation of Ohio Application January: 17, 1931. Serial'No. 509,386

4 qlaims. (o1.{214-s'6 The present invention relates, broadly to the art of effecting or controlling the movement of certain structures, andmore particularly to an.

apparatusand method adapted for controlling ,5 the movement ofpartly or substantially completely counterweighted structures such as charg-.

ing bells for furnaces and the like. While for purposes'of illustration the invention is hereinafter described as. applied to .the control of bells for blast furnaces, it will be understood that the utility of the invention is not thus limited.

In blast furnaces, for example, as at present constructed, there is provided a pair of bells adjacent the upperend thereof, which bells are utilized for controlling thecharging of the furnace. As ordinarily constructed, the bellsopen by gravity, being connected through a suitable system of links, levers, cables and the like to operating mechanism effective for returning the bells to their sealing position. Withsuch ,a construction, difliculties are often experienced due to the sticking of the bell in, its seat. In such case, the elevating mechanism for the bell is operated to release the sameand continues to produce more and more slack in the bell cable.

.It not infrequently happens that the bell will suddenly release and drop a. considerable distance as permitted by the slack in the cable. Should this slack be of any considerable extent so as the sudden load on the cable will result in-snapping the same permitting the bell to fall into the furnace. Such a happening necessarily means that the furnace must be shut down and thebell repaired or replaced beforeoperationscan be resumed. The complete costqincidental to such a happening may amount to as much as ten thousand dollars ($10,000.00)v in addition to the inconvenienceresulting from the shutting down of the furnace itself.

It is one of the objects of the presentinvention to preclude the possibility of any such occurrence and at the same time to provide a bell operation of such nature as to insure safety at all times in the operation thereof In the accompanying drawing I have shown more or less diagranunatically, forpurposes of illustration only, one embodiment of the present invention, the single figure of the drawingillusthe bells in position therein together with the mechanism for effectingand controlling the operation thereof. a

In the drawing there is illustrated the upper portion of a blast furnace 2 having suitably to permit any appreciable acceleration of the bell,

trating the upper portion of a blast furnace withmounted in the upper end thereof an upper and smaller bell 3 and a lower and larger bell 4. These bells are herein illustrated as beingconcentrically arranged andsusceptibleof individual control whereby the desired loading or charging of the furnace may be accomplished.

The lower bell 4 is illustrated as suspended by a link 5 secured to one end of a bell lever 6 having a pivotal'mounting 'l. The opposite end of the bell lever; is connected by a bell cable 8 to a con-- 'trolling cylinder 9. i

In like mannen'the upper bell 3 is connected by a suitable link 10 to one end of a bell lever 11, the opposite end of whichis connected by a bell cable 12 to a second cylinder 14. I

For purposes ofunderstanding the present invention, it maybe assumed that the upperbell 3 has been'lowered to provide a charge of fuel 15 above, the bell 4 and supported thereby, the upper bell 3 having been restoredrto its full line position as illustrated in the drawing. At such time as it is desired tolower the bell 4 and thereby charge the fuel 15 into the furnace, a'supply of suitable fluid under pressure may be delivered from a manifold 16 into a connection'l'l leading to a four way controlling valve 18. This valve will be so turned as topermit'theoperating fluid .to pass therethrough into a line 19 communicating with a pressure regulator 20. The outlet of the pressure regulator 20 communicates through a connection 21 to therinterior of a stationary piston rod 22 through which it passes into the space between the cylinder and piston 23 by means of a'piston port 24. This fluid will be effective, under normal conditions of operation, -for raising the cylinder Qtoprovide the necessary slack in the bell cable 8 to permit the belllever 6 to move in aclockwise direction about its pivotal mounting '7 and thus permit the bell 4 to lowerby gravity. 7

Such lowering operation having been completed, the valve 18jis turned to its opposite position there by connecting the opening lines 21 and 19 to an exhaust line 25 and connectingthe closing line 26 to the pressure line 17. Operating fluid passes through the closing line 26 into a passageway 27 in the hollow piston rod 22, and is discharged therefrom through a port 28 into the cylinder 9 below the piston 23. This fluid is effective for returning the cylinder to its lower position, and thereby raising the bell against its seat.

Inasmuch as it is not desired to have the fluid exhausted from above the piston 23 pass through a the pressure regulator 20, I preferably provide the opening line with a by-pass 29 provided with a one-way check valve 30, this check valve being so arranged as to permit fluid to exhaust therethrough while preventing opening fluid under pressure from by-passing the pressure regulator.

The pressure regulator before referred to constitutes an impot ant part of the present inven: tion. This regulator having been installed in the opening line, a test is made to ascertain the amount of pressure required to lift the cylinder 9 when it is detached from the bell cable 8. When thus detached, its effective load is not partly counterbalanced by the bell Theamount of pressure having been ascertained, the regulator 20 is set so as to make it impossible to introduce pressure to such an extent into the space -between the cylinder head and the piston 23. 5 The regulator thus makes it impossible toprovide suflicient pressure for lifting the cylinder 9 at such times as the bell 4 does not assist in raising the same by its counterbalancing effect. Thus, in actual operation, should thebell 4 stick-to its seat, the fluid pressure supplied through the opening line will be insuflicient to raise the cylinder 9 and provide any slack'in the cable 8. On the contrary, should the bell 4 immediately commence to lower "by gravity, the supplied pressure will be suflicient to continue'the upward movement of the cylinder 9 to the extent required for complete opening of the bell.

The invention thus provides a positive and automatic means of preventing the bell actuating mechanism from functioning at such times as the bell fails to'lower simultaneously with the actuation thereof. This is true, regardless of pressure variations in the manifold 16, such variations being automatically compensated by the pressure regulator 20. The mechanism for operating the bell 3 is of similar construction as will readily be apparent without any detailed description of the conponent parts thereof.

To those skilled in the art, it will be apparent that the present invention provides an automatic control system effective for producing a controlled operation of partly or substantially completely counterbalanced or counterweighted structures under such conditions as to preclude injury to the parts by undue slackness at any time in the supporting connections. 'As before pointed out, the invention is of utility in connection with any partly or substantially completely counterweighted structures regardless of their particular construction or function, but is especially important in the operation of furnace bells and the like wherein considerable losses result from an improper or uncontrolled operation of the bell after be referred to in the claims as counterbalanced structures or bells, regardless of the effectiveness or. extent of counterbalancing.

While I have herein ilustrated and described a preferred embodiment of'my invention, it will be understood that changes in the construction and operation of the parts may be made without departing either from the spirit of the invention or the scope of my broader claims.

I claim:

1. In combination, a fluid motor, a structure to be controlled thereby and constituting counterbalancing means therefor, a fluid pressure supply connection for said motor including a regulator precluding a suflicient fluid supply to said motor to lift the dead weight thereof, and an exhaust around said regulator.

2. The combination with a blast furnace having a charging bell, of a counterbalance for the bell, a connection including a cable between the bell and its counterbalance, and fluid pressure operated means for raising and lowering the counterbalance including a cylinder and piston, a fluid pressure supply, and valved connections from the fluid pressure supply to the cylinder having a branch for connecting the cylinder to the fluid pressure supply for lowering the counterbalance, and a second branch having pressure reducing means for supplying to the cylinder a reduced fluid pressure suflicient to raise the counterbalance when assisted by the weight of the bell but insufficient to raise the entire weight of the counterbalance, whereby slackening of the cable is prevented.

3. The combination with a blast furnace having a charging bell, of a counterbalance for the bell, a connection including a cable between the bell and its counterbalance, and fluid pressure operated means for raising and lowering the counterbalance including a cylinder and piston, a fluid pressure supply, and valved connections from the fluid pressure supply to the cylinder having a branch for connecting the cylinder to the fluid pressure supply for lowering the counterbalance,

and a second branch having a reducing valve therein through which the fluid under pressure flows to the cylinder at a pressure suflicient to raise the counterbalance assisted by the weight of the bell but insuflicient to raim the entire weight of the counterbalance, whereby slackening of the cable is prevented.

4. The combination with a blast furnace having a charging bell, of a counterbalance for the bell, 'a connection including a cable between the bell and its counterbalance, and fluid pressure operated means for raising and lowering the counterbalance including a cylinder and piston, a fluid pressure supply, and connections for supplyingfluid under pressure'to the cylinder during both the raising and lowering movements thereof having provision for limiting the fluid pressure applied for raising'the counterweight to a value insuflicient to raise the counterweight in case by-pass including a'one way check valve disposed

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