U.S. patent number 3,866,806 [Application Number 05/337,252] was granted by the patent office on 1975-02-18 for operating mechanism for slidable gates and method of operating slide gate.
This patent grant is currently assigned to United States Steel Corporation. Invention is credited to Earl P. Shapland, Jr..
United States Patent |
3,866,806 |
Shapland, Jr. |
February 18, 1975 |
OPERATING MECHANISM FOR SLIDABLE GATES AND METHOD OF OPERATING
SLIDE GATE
Abstract
An operating mechanism for slidable gates which are used to
control flow of liquid from a bottom-pour vessel, and a
flow-controlling method. The mechanism is particularly useful for
controlling teeming of liquid steel from a tundish into a
continuous-casting mold. Most slidable gates either fully open or
fully close the outlet of a vessel. The present invention enables
the outlet to be partially open, whereby the stream discharging
therefrom can be throttled. The mechanism includes a main drive
means for pushing gates from a ready position to a slow-motion
region under the vessel outlet. The slow-motion region of an
orifice gate extends at least from a position in which the vessel
outlet is partially open to a position in which it is fully open.
An opposed auxiliary drive serves to retard movement of a gate as
soon as it reaches the slow-motion region. Thereafter, the main
drive pushes an orifice gate slowly and under close control to any
desired teeming position within the slow-motion region. The
mechanism also includes an improved arrangement for conducting
gases to the nozzle at the vessel outlet to prevent skulls from
forming, and an improved means for attaching a pouring tube to its
holder.
Inventors: |
Shapland, Jr.; Earl P.
(Champaign, IL) |
Assignee: |
United States Steel Corporation
(Pittsburgh, PA)
|
Family
ID: |
23319764 |
Appl.
No.: |
05/337,252 |
Filed: |
March 1, 1973 |
Current U.S.
Class: |
222/600;
222/561 |
Current CPC
Class: |
F15B
11/072 (20130101); B22D 41/24 (20130101); F15B
11/16 (20130101); B22D 41/42 (20130101); F15B
2211/8855 (20130101); F15B 2211/71 (20130101) |
Current International
Class: |
B22D
41/22 (20060101); B22D 41/24 (20060101); B22D
41/42 (20060101); F15B 11/16 (20060101); F15B
11/00 (20060101); B22d 037/00 () |
Field of
Search: |
;222/334,504,561,DIG.7 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Reeves; Robert B.
Assistant Examiner: Scherbel; David A.
Attorney, Agent or Firm: Wood; Walter P.
Claims
1. An operating mechanism for slidable gates which are used to
control flow of liquid from a bottom-pour vessel, said mechanism
comprising a frame for attachment to the bottom of the vessel,
gate-supporting means on said frame for slidably supporting blank
and orifice gates for movement between a ready position, a
slow-motion region under the vessel outlet, and a removal position
beyond said slow-motion region, the slow-motion region of an
orifice gate extending at least from a position of the gate in
which the vessel outlet is partially open to a position in which it
is fully open, and main and auxiliary drive means carried by said
frame at opposite ends of the path of gate movement, said main
drive means being adapted to push a gate from said ready position
into said slow-motion region and to displace a gate already in said
slow-motion region into said removal position, said auxiliary drive
means including means for retarding the rate of movement of gates
as they reach said slow-motion region, which last-named means
permits an orifice gate to move rapidly from said ready position to
said slow-motion region and thereafter slowly and under close
control in either direction to any teeming position within said
2. A mechanism as defined in claim 1 comprising in addition means
on said frame spaced below said gate-supporting means for
supporting a pouring
3. A mechanism as defined in claim 2 in which the means for
supporting the pouring tube enables said main drive means to push a
replacement pouring tube from a ready position into a position
aligned with the vessel outlet, and to displace an old pouring tube
from alignment with the outlet into a
4. A mechanism as defined in claim 1 in which said main and
auxiliary drive means include fluid pressure cylinders and pistons
mounted at opposite
5. A mechanism as defined in claim 4 in which said retarding means
include
6. The combination, with a bottom-pour vessel having a nozzle in
its bottom wall and blank and orifice gates for controlling flow of
liquid through said nozzle, of an operating mechanism attached to
the bottom wall of said vessel for supporting and positioning said
gates, said mechanism being
7. A combination as defined in claim 6 further comprising a pouring
tube
8. A combination as defined in claim 6 in which said mechanism
forms an assembly which can be removed as a unit from said vessel,
and re-attached
9. In an operating mechanism for slidable gates which are used to
control flow of liquid from a bottom-pour vessel, which mechanism
comprises:
a frame for attachment to the bottom of the vessel and including a
plate and rails dependently supported from said plate;
opposed gate-supporting levers pivoted to said frame, said rails
being interrupted to accommodate said levers; and
a main fluid pressure cylinder and piston and a ram operated
thereby mounted at one end of said frame;
the improvement which comprises:
an auxiliary cylinder and piston and an opposed second ram operated
thereby mounted at the other end of said frame;
said rails being adapted to support blank and orifice gates for
movement between a ready position adjacent said first-named ram, a
slow-motion region on said levers under the vessel outlet, and a
removal position adjacent said second ram;
the slow-motion region of an orifice gate extending at least from a
position of the gate in which the vessel outlet is partially open
to a position in which it is fully open;
said first-named ram being adapted to push a gate from said ready
position into said slow-motion region, and to displace a gate from
the latter region to said removal position with said second ram in
abutting relation with the displaced gate;
and means in said auxiliary cylinder for retarding the rate of
movement of the gates as they reach said slow-motion region,
whereby an orifice gate moves rapidly from said ready position to
said slow-motion region and thereafter slowly and under close
control in either direction to any
10. A mechanism as defined in claim 9 in which the gates can be
inserted sideways into their ready position and removed sideways
from their removal
11. A mechanism as defined in claim 9 in which said frame includes
in addition rails spaced below said first-named rails for
supporting a pouring tube, said mechanism further comprising
opposed tube-supporting levers below said gate-supporting levers,
said second-named rails being interrupted to accommodate said
tube-supporting levers, and means on said first-named ram for
pushing a pouring tube from said second rails to said
12. A mechanism as defined in claim 9 in which said retarding means
includes a dashpot within said auxiliary cylinder, said check
valve
13. The combination, with a bottom-pour vessel having a nozzle in
its bottom wall, a mounting plate fixed to the bottom wall and
surrounding said nozzle, a top plate under said mounting plate, and
blank and orifice gates for controlling flow of liquid through said
nozzle, of an operating mechanism for supporting and positioning
said gates, said mechanism being removably attached to said
mounting plate and constructed as defined in
14. A combination as defined in claim 13 in which said mounting
plate carries a plurality of depending lugs, and the frame of said
mechanism includes a plate having holes matching and receiving said
lugs, and pins
15. A method of controlling flow of liquid from a bottom-pour
vessel, said method comprising positioning a blank gate under the
vessel outlet, hydraulically displacing the blank gate with an
orifice gate, and during the displacing step moving the orifice
gate rapidly from a ready position to a slow-motion region under
the outlet and thereafter slowly moving the orifice gate under
close control to a teeming position within the slow-motion region
by retarding the gates with a dashpot in the hydraulic circuit,
said slow-motion region of an orifice gate extending at least from
a position of the gate in which the vessel outlet is partially
open
16. In an operating mechanism for slidable gates which are used to
control flow of liquid from bottom-pour vessel, said mechanism
comprising:
a frame for attachment to a vessel;
gate supporting means on said frame for slidably supporting blank
and orifice gates for movement between a ready position, a position
under the vessel outlet and for removal; and
drive means for moving said gates;
the improvement in which:
said orifice gate is movable rapidly from said ready position to a
slow-motion region under the vessel outlet extending at least
between a position in which the outlet is partially open and a
position in which it is fully open; and
said drive means is plural speed, and has means for moving said
orifice gate at a first rapid speed from said ready position to
said slow-motion region and means for moving said orifice gate at a
second slow speed through said slow-motion region.
Description
This invention relates to an improved operating mechanism for
slidable gates which are used to control flow of liquid from a
bottom pour vessel, and to an improved flow-controlling method.
Although my invention is not thus limited, my operating mechanism
is particularly useful when applied to a vessel from which liquid
metal is teemed into a receiver therebelow, for example, a tundish
from which liquid steel is teemed into a continuous-casting mold.
My control method is particularly useful when applied in the
corresponding operation. Reference can be made to an earlier patent
of James T. Shapland, U.S. Pat. No. 3,352,465, of common ownership
for a showing of two forms of slidable gate constructions used
heretofore on bottom-pour vessels, and to a number of later
patents, also of common ownership, for showings of modifications
and improvements to the construction shown in the first Shapland
patent.
FIGS. 1-3 of the Shapland patent show a reciprocating gate,
different portions of which form a closed area and an orifice. The
closed area is positioned under the vessel outlet to prevent flow
of liquid from the vessel, and the orifice is positioned thereunder
to permit flow. FIGS. 4-6 of the patent show "slide-through" gates,
wherein each gate is either a blank or an orifice gate. A blank
gate is positioned under the vessel outlet to prevent flow, and
displaced with an orifice gate to permit flow. With either form,
the vessel outlet is either fully open or fully closed. There is no
provision for teeming through a partially open outlet, that is,
using the gate to throttle the pouring stream. Most other
gate-operating mechanisms with which I am familiar have a similar
lack of flexibility.
In certain operations, it would be advantageous to throttle a
pouring stream. One example is in continuously casting
aluminum-killed steel, where oxygen released from the steel
combines with excess aluminum and forms aluminum oxide which
deposits around the tundish outlet and gate orifice and restricts
flow. If the gate with the orifice could be placed in a throttling
position in which the outlet is only partially open at the
beginning of a casting operation, the effective opening could be
increased gradually as the cast progresses to maintain a constant
teeming rate and thus compensate for the oxide build-up. Also the
gate might be moved momentarily to a position in which the outlet
is fully open to flush away the deposit and then returned to a
throttling position.
An object of my invention is to provide an improved gate-operating
mechanism and an improved flow-controlling method which enable me
to throttle a stream of liquid as it discharges through the outlet
of a bottom-pour vessel.
A further object is to provide an improved gate-opening mechanism
and an improved flow-controlling method which enable me to move an
orifice gate quickly from a ready position into a slow-motion
region under a vessel outlet, and thereafter slowly and under close
control in either direction to any desired teeming position within
the slow-motion region.
A further object is to provide an improved gate-operating mechanism
which enables me to change readily either the blank gate or the
orifice gate during the course of a teeming operation.
A further object is to provide a gate-operating mechanism which
affords the foregoing advantages and at the same time can be used
for positioning a separate pouring tube beneath the gate.
A further object is to provide an improved means for introducing
gas to a permeable plug in a blank gate and avoiding any need for
connecting pipes or tubes to movable parts, and also affording
automatic gas shut off when the vessel outlet is opened to begin
teeming.
A further object is to provide an improved means for attaching a
pouring tube to a holder which can be used in conjunction with a
slidable gate.
In the drawings:
FIG. 1 is a top plan view of my gate-operating mechanism and the
mounting plate for attaching the mechanism to a bottom-pour
vessel;
FIG. 2 is a side elevational view of a portion of a bottom-pour
vessel with my gate-operating mechanism attached;
FIG. 3 is a longitudinal section on line III--III of FIG. 1;
FIG. 4 is a cross section on line IV--IV of FIG. 2, but showing a
blank gate positioned under the vessel outlet;
FIG. 5 is a cross section on line V--V of FIG. 2, but showing a
blank gate positioned under the vessel outlet;
FIG. 6 is a bottom plan view of the mounting plate;
FIG. 7 is an exploded perspective view of the pouring tube and its
holder illustrating my preferred attaching means;
FIG. 8 is a graph comparing the relation between the flow of metal
from a tundish and the head of metal therein with the outlet
partially open, and the outlet fully open; and
FIG. 9 is a schematic diagram of the hydraulic and pneumatic
circuits embodied in the mechanism.
VESSEL AND MOUNTING PLATE
FIGS. 2, 3, 4, and 5 show a portion of a conventional bottom-pour
vessel for handling liquid metals, for example, a tundish used to
teem metal into a continuous-casting mold. The vessel includes a
metal shell 10, a refractory lining 12, and a refractory pouring
nozzle 13 extending through the lining and shell and defining the
outlet. A mounting plate 14 is fixed to the bottom wall of the
vessel surrounding the lower portion of the nozzle. Preferably I
interpose a sheet 15 of heat insulating material, such as asbestos
mill board, between the bottom wall and the mounting plate. As best
shown in FIG. 6, the mounting plate has horizontal passages 16 and
17. The passages 16 communicate with series of nozzles 18 fixed to
the underside of the mounting plate for supplying cooling air to
the springs embodied in my operating mechanism, hereinafter
described. The passage 17 has an outlet port 17a for supplying gas
(inert and/or oxygen) to the vessel nozzle 13 as also hereinafter
described. The mounting plate has a plurality of depending lugs 19
for attaching my operating mechanism to the vessel. The lugs have
transverse holes 20.
CONSTRUCTION OF THE GATE OPERATING MECHANISM
I construct my operating mechanism as an assembly which I can
install on the mounting plate 14 or remove therefrom as a unit. The
mechanism has a fabricated frame 21 on which I mount the other
parts. As best shown in FIG. 2, this frame includes a horizontal
plate 22, a continuous flange 23 depending from one side edge of
the plate, and vertically spaced upper and lower rails 24 and 25
projecting inwardly from the flange. At its opposite side edge, the
plate carries depending flange segments 26, 27, and 28 from which
horizontally spaced upper rail segments 29, 30 and 31 respectively
project inwardly. Horizontally spaced lower rail segments 32 and 33
project inwardly from the flange segments 26 and 28 respectively.
The foregoing parts of the frame are rigidly connected to one
another, but preferably the lower rail 25 and rail segments 32 and
33 and the lower portions of the flange 23 and flange segments 26
and 28 can be removed. The purpose of the lower rail and rail
segments is to support a pouring-tube holder 34, hereinafter
described. When no pouring tube is used, the parts on which it
would have been supported are not needed. Plate 22 has vertical
holes 35 and horizontal holes 36 communicating with the respective
vertical holes. The lugs 19 on the mounting plate 14 match the
vertical holes and are received therein. I insert pins 37 through
the aligned horizontal holes 20 and 36 in the lugs 19 and plate 22
respectively to hold the operating mechanism on the vessel. As
hereinafter explained in detail, the upper rail 24 and rail
segments 29, 30 and 31 are adapted to support refractory blank
gates 38 and orifice gates 39 for movement along a linear path
between a ready position, a slowmotion region under the nozzle 13,
and a removal position beyond the nozzle.
Plate 22 has a central opening 41 which receives a stationary
refractory top plate 42 (FIGS. 3, 4 and 5). The latter has the
usual orifice 43, which is aligned with the base of the nozzle 13.
Since the refractory plate is exposed directly to liquid metal, it
must be replaced frequently. Replacement is simple, since the top
plate is accessible when the frame 21 is removed from the mounting
plate 14.
I mount a main fluid-pressure cylinder 46 on frame 21 at one end of
the path of gate movement, and an auxiliary fluid-pressure cylinder
47 at the other end thereof (FIGS. 1,2 and 3). The main cylinder 46
contains a reciprocable piston 48 and a piston rod 49, which
carries a ram 50 at its free end. Similarly, the auxiliary cylinder
47 contains a reciprocable piston 51 and a piston rod 52, which
carries an opposed second ram 53 at its free end. A hydraulic fluid
line 54 and a compressed air line 55 are connected to the back and
front ends of the main cylinder 46 respectively. Similarly, a
hydraulic fluid line 56 and a compressed air line 57 are connected
to back and front ends of the auxiliary cylinder 47.
At opposite sides of the nozzle 13, the frame 21 carries opposed
gate-supporting levers 60 and opposed tube-holder-supporting levers
61 which are best shown in FIGS. 4 and 5 respectively. The rails 24
and 25 and rail segments 30 are interrupted to accommodate the
levers 60 and 61, while the levers 61 are slotted to accommodate
the levers 60 (FIG. 4). The gate-supporting levers 60 are pivotally
mounted on crowned washers 62 carried by bolts 63 which depend from
flange 23 and flange segment 27 at opposite sides of the gate 38 or
39. The flange 23 and flange segment 27 have vertical bores 64
within which I mount compression springs 65 and plungers 66. The
springs act downwardly through the plungers against the outboard
ends of levers 60, whereby the inboard ends act upwardly against
the gate and thus press the gate firmly against the top plate 42
thereabove. The tube-holder supporting levers 61 are pivotally
mounted on crowned washers 67 carried by bolts 68 which depend from
flange 23 and flange segment 27 at opposite sides of the tube
holder 34. Springs 69, which are similar to springs 65, act
downwardly through plungers 70 against the outboard ends of levers
61, whereby the inboard ends act upwardly against the tube holder
and then press the tube holder firmly against the gate 38 or 39
thereabove. The bores which receive the springs lie directly under
the respective nozzles 18 in the mounting plate 14 to admit cooling
air to the springs.
OPERATION OF THE GATE-OPERATING MECHANISM
Before filling the vessel with metal or other liquid, I position a
blank gate 38 under the stationary top plate 42, where it is
supported on the inboard arms of the gate-supporting levers 60. The
ram 50, operated by the main cylinder 46, is fully retracted. The
back end of the auxiliary cylinder 47 contains hydraulic fluid,
whereby the second ram 53 is extended into abutting relation with
the end of the blank gate 38. I insert an orifice gate 39 sideways
through the space between the upper flange segments 26 and 27 into
a ready position, where it rests on the rail 24 and on rail
segments 29 and 30. The orifice gate 39 has an orifice 73 of the
same diameter as the orifice 43 in the top plate 42. The ends of
the gates 38 and 39 approximately abut.
When I wish to commence teeming, I introduce hydraulic fluid to the
back end of the main cylinder 46 via the line 54. Ram 50 is driven
toward the nozzle 13 and thus pushes the orifice gate 39 toward the
nozzle and displaces the blank gate 38 from the gate-supporting
levers 60 toward a removal position beyond the nozzle. The blank
gate acts against ram 53 and pushes the piston 51 into a retracted
position within the auxiliary cylinder 47. The back end of the
piston 51 carries a cylindrical plug 74 (FIG. 3). The back wall of
cylinder 47 has a bore 75, which is adapted to receive plug 74, and
with which the hydraulic line 56 communicates. The back wall also
has a restricted L-shaped passage 76 which affords the only
communication between the interior of the cylinder and the bore 75
when plug 74 is received within the bore. A screw 77, which is
threadedly engaged with the cylinder wall, controls the effective
cross-sectional area of passage 76. Thus the plug 74, bore 75, and
passage 76 form a dashpot. I proportion the parts so that the plug
first enters the bore when the orifice gate 39 reaches a
slow-motion region in which it is supported on the gate-supporting
levers 60 and its orifice 73 is nearing or partially under the
nozzle 13. The slow-motion region of an orifice gate extends at
least from a position of the gate in which the nozzle is partially
open, as shown in FIG. 3, to a position in which the nozzle is
fully open. Until the plug enters the bore, hydraulic fluid
discharges freely from the auxiliary cylinder, whereby the parts
move rapidly until the gate reaches the slow-motion region. As soon
as the plug enters the bore, hydraulic fluid can escape from the
auxiliary cylinder only via the restricted passage 76, whereupon
the parts move slowly and under close control in either direction
into any desired teeming position within the slow-motion
region.
While the teeming operation takes place, the upper rail segments 30
and 31 support the blank gate 38 in its removal position, and the
gate-supporting levers 60 support the orifice gate 39, as already
stated. If I wish to remove the blank gate and replace it with
another, I introduce air under pressure to the front end of the
auxiliary cylinder 47 via line 57. Piston 52 is driven into a more
retracted position, whereupon I can remove the blank gate sideways
through the space between the flange segments 30 and 31, and insert
another in its place. If I wish to stop pouring, I introduce
hydraulic fluid to the back end of the auxiliary cylinder 47 and
thus push the blank gate 38 from its removal position back under
the orifice 43, slowly at first until plug 74 clears the bore 75
and then rapidly. If I wish to change orifice gates, I first remove
the blank gate by the procedure already described, whereafter I
introduce air to the front end of the main cylinder 46 via the line
55 and thus drive the piston 48 and ram 50 into a retracted
position. I insert a new orifice gate into the ready position and
next operate cylinder 46 to push the new gate into the slow-motion
region on the gate-supporting levers 60, displacing the old orifice
gate into its removal position. Alternatively, I may introduce
hydraulic fluid to the back end of the auxiliary cylinder 47 and
drive the blank gate back under the nozzle and the old orifice gate
back to the ready position, from which I remove it sideways. I can
then insert a new orifice gate into the ready position and proceed
as originally described.
FIG. 8 is a graph which shows the relation between the flow rate
and head of steel in a tundish (A) with the gate orifice 73 in an
initial throttling position at the beginning of the slowmotion
region, and (b) with the gate orifice in its fully open position.
In this instance, the initial throttling position is with the
circumference of the gate orifice 73 lying on the center of the
orifice 42 in the top plate 41, that is, the effective area of the
opening is about 40 percent of the area at the fully open position.
The abscissae of the graph represent the flow rate and the
ordinates the head. In each instance, the flow rate is directly
proportional to the head. With a given size of orifice and a given
initial throttling position, I can produce a relation anywhere
between the lines (A) and (B) of the graph.
HYDRAULIC AND PNEUMATIC CIRCUITS
FIG. 9 is a simplified diagram of the hydraulic and pneumatic
circuits embodied in my mechanism. The hydraulic circuit includes a
tank 80 which contains hydraulic fluid. A feed line 81 extends from
the tank to a pump 82 and thence to an inlet port of a four-way
valve 83. A return line 84 extends from an outlet port of the valve
back to the tank. The aforementioned hydraulic lines 54 and 56
extend from this valve to the main and auxiliary cylinder 46 and 47
respectively. The pneumatic circuit includes a compressed air tank
85. A feed line 86 extends from tank 85 to an inlet port of another
four-way valve 87, which has an exhaust 88. The aforementioned air
lines 55 and 57 extend from the latter valve to the main and
auxiliary cylinders 46 and 47 respectively. FIG. 9 shows the valves
83 and 87 in their neutral positions. When I wish to introduce
hydraulic fluid to cylinder 46 or 47, I shift the movable element
of valve 83 left or right respectively. Similarly, I shift the
movable element of valve 87 to introduce air to either cylinder.
The circuit may include various refinements, not shown, such as
filters, heaters, and accumulators.
INTRODUCTION OF GAS TO NOZZLE
The blank gate 38 illustrated has a gas-permeable plug 91 which is
aligned with orifice 43 when the blank gate is positioned to close
the vessel outlet. As known in the art, I introduce gas to the base
of nozzle 13 through the permeable plug to prevent skulls from
forming and blocking the nozzle. Preferably, I introduce an inert
gas, usually argon, to stir the metal in the vessel until a few
seconds before I am ready to commence teeming. At that point, I
introduce a brief burst of oxygen to burn away any skull which may
have formed in the nozzle bore. The inclusion of a permeable plug
of course is optional, but when I include it, I prefer to conduct
gas to the plug through a novel arrangement of passages, which are
best shown in FIGS. 1 and 5 and which I shall now describe.
As already mentioned, the mounting plate 14 has a passage 17 and an
outlet port 17a. The top plate 42 has a horizontal passage 92 and
inlet and outlet ports 92a and 92b communicating with this passage
and extending through the top and bottom faces respectively. The
blank gate 38 has a horizontal passage 93, an inlet port 93a
communicating with this passage and extending through the top face,
and a circular passage 94 communicating with passage 93 and
surrounding the permeable plug 91. When the parts are assembled,
the outlet port 17a in the mounting plate and the inlet port 92a in
the top plate 42 are aligned. Preferably, I insert a sealing ring
95 between the top plate and mounting plate at the juncture of the
outlet and inlet ports. When the blank gate 38 is properly
positioned under the nozzle 13, the inlet port 93a in the gate and
the outlet port 92b in the top plate are aligned. I connect a gas
line 96 to either end of passage 17 in the mounting plate, whereby
gas may flow through passages 17, 92, 93 and 94 to the permeable
plug 91. The other end of passage 17 of course is plugged.
My novel arrangement of passages eliminates need for connecting a
pipe or tube to a movable part of the mechanism to conduct gas to
the plug, as has been the practice in the prior art. A further
advantage is that the gas is immediately and automatically shut off
whenever the blank gate is displaced from the nozzle. It should be
pointed out that my novel arrangement of passages has general
utility in gate-operating mechanisms which embody a mounting plate,
a top plate, and a permeable plug in the slidable gate. Its use is
not confined to the specific mechanism described herein.
POURING TUBE CONSTRUCTION AND OPERATION
If I use a pouring tube, I assemble the tube 98 on its
aforementioned holder 34. As best shown in FIg. 7, the holder 34 is
formed of a flat rectangular refractory block 99 and a metal frame
100 covering the side and end edges and bottom of the block. The
frame is fixed to the block with a layer of mortar 101. The
underside of the frame has a depending skirt 102 which receives the
upper end of tube 98. The skirt has four symmetrically arranged
slots 103. The upper portion of the tube has a surrounding metal
band 104 and is grooved as indicated at 105. I insert a U-shaped
wire clip 106 through the slots 103 and grooves 105 to fix the
pouring tube to the holder. The block 99 has a central orifice 107
aligned with the tube bore. The grooves 105 preferably extend
through only relatively small arcs, whereby the tube is positioned
automatically always in the same orientation with respect to the
holder when the two parts are assembled. This is an important
advantage where the tube has outlets 108 in its side walls, since
it assures that these outlets are oriented properly with respect to
a continuous casting mold. If side outlets are not used, groove 105
may be continuous around the tube circumference. When either the
holder or tube requires replacement, it can be replaced without
replacing the other.
When I install the holder 34 and pouring tube 98 in the mechanism,
I insert the holder sideways through the space between the lower
rail segment 32 and the holder-supporting levers 61, where it is in
a ready position resting on the lower rail 25 and rail segment 32.
Rams 50 and 53 have depending flanges 109 and 110 respectively
adapted to abut opposite ends of holder 34. Initially I operate the
main cylinder 46 to extend ram 50 and push the holder into a
position in which its orifice 107 is aligned with nozzle 13.
Preferably I insert a U-shaped stop 112 through appropriately
placed holes in the lower rail 25 to retain the holder and tube
exactly in this position. When I replace a tube holder and tube, I
insert a replacement holder into the ready position the same as
before, and operate cylinder 46 to push the replacement holder onto
the holder-supporting levers 61, where it displaces the old onto
the lower rail 25 and rail segment 33. I can remove the holder
sideways through the space between the rail segment 33 and the
levers 61.
From the foregoing description, it is seen that my invention
affords a simple method and mechanism for operating slidable gates
which control flow of liquid from a bottom-pour vessel and for
using the orifice gate to throttle the pouring stream. The
invention enables gates or pouring tubes to be removed and replaced
readily at any time. Another feature is that the pouring tube is
removably attached to its holder, yet always properly oriented.
* * * * *