Note: Descriptions are shown in the official language in which they were submitted.
VALVE SUITABLE FOR CONTROLLING TEEMING
FROM FURNACE TAPHO~ES
The present invention relates to a ~alve suit-
able for controlling teeming from a ve~sel outlet
such as a furnace taphole.
When an arc furnace is t;~pped conventionally,
molten metal and slag flow over the furnace pouring lip
as the furnace is tilted. The metal and slag then run
down a trough~ where such is provided, and gather in a
ladle~ The presence of slag i5 a considerable inconven-
ience, Thus, it would be advantageous to be able to empty
the furnace of its molten metal and to leave the slag
behind.
By providing the furnace with a taphole located
well below the top thereof, it is possible to pour off
the molten metal alone when the furnace is tilted. Some
form of stopper is needed to close the taphole until
pouring lS to take place. Better still would be a valve
openable and closable at will, for this would facilitate
.,
9~
the filling of several ladles from one furnace charge,
and the furnace would only need tilting once, at the
start of the emptying operation.
In principle a sliding gate valve might appear
suitable for controlling flow out of the taphol~.
~owever, no known sliding ga~e valve is sui~a~le. The
known valve mechanism occupy considerable space ~o either
side thereof i.e. along the direction of movement of
the sliding valve plate. Ade~uate space is absent in
the region of a furnace taphole, however, in part due to
the presence of the pouring trough.
An object of the presen~ invention has been to
adapt the sliding gate valve concept to suit a furnace
taphole arrangement, and a mechanism has been devised
in which the sliding valve plate is biased towards the
taphole and is moved to and fro fxom above the trough.
Accordin~ to the present invention, there is
provided a valve mechanism for controllin~ metal flow
from a vessel outlet, comprising an orificed stationary
valve plate, a companion slidable valve plate for
covering or exposing the orifice of the former to close
or open the valve to flow, extending obliquely to the
slidable plate for an actuating member moving the slid-
able plate, spring means acting to bias the actuating
member against the sli~able plate to press the slidable
-- 2 --
~z~
plate to the stationary plate, and mean~ guiding the
actuating member for displacement along a predetermined
path wherein a portion of the actuating member engaging
the slidable plate moves in a plane parallel to the
s contac~ing faces of the valve plates.
Although the present valve has been devised
particularly with furnaces in mind, it has application to
other vessels~ Thus, the compact form of the valve and
~he locati~n, to one side of a vessel teeming opening,
of its structure for biassing and for moving the slide
plate to and fro may be found of significant convenience
for some ladles, tundishes and other vessels from which
molten metal is to be teemed.
The invention will now be described in more
detail by way o~ example with reerence to the accompany~
ing drawings, in which:
Fig. 1 is a front elevation of an arc furnace
fitted with a taphole valve mechanism according to the
invention;
~o Fig. 2 is a side elevational view of the
equipment shown in Fig. l;
Fig. 3 is an enlarged sectional elevation of
the valve arrangement and ducting leading thereto from
the taphole; and
-- 3 --
~2~
Fig. 4 is a diagrammatic geometrical analysis
of the valve mechanism.
Referring first to ~ig. 3, a taphole insert 10
is positioned in a furnace taphol~, the inser~ 10 having
a flow passage of o~al cross-sectionO Abuttingly
sealed to the taphole insert 10 is an intermediate duct
11 having a flow passage which changes from oval to
circular cross section. A nozzle piece 1~ is cemented
into the duct 11 and a valve generally designated 14 is
disposed at the end of the nozzle piece 12 remote from
the taphole, and is sealed thereto.
In essence, the valve 14 comprise~ a s~ationary
apertured valve plate 15 of ring form and a slide plate
16 of disc form biased thereagainst. Clamps 17 IFig. 1)
secuxe the plate 15 in abutment with noæzle piece 12.
The slide plate 16 is movable in an upward direction, to
uncover the opening 18 in the stationary plate 15 and
thus open the tapping channel, by an actuating member 20
which i5 also arranged to thrust the plate 16 against
the plate 15. When the tapping channel is opened by
raising the slide plate 16~ metal flows from the furnace
thxough the taphole insert 10, the intermediate duct and
the stationary plate 15, issuing from the latter into
pouring trough 21. Metal flows then down thQ trough
into the receiving vessel or ladle.
-- 4 --
When the slide plate lS is shifted upwardly to
open the ~alve 14 completely it travels a distance almost
equal ~o its diameter. The width of the ring-shaped plate
15, that is the difference between its inner and outer
radii, is substantially smaller than the aforesaid
distance. Means is therefore provided to support the
slide plate 16 as it is moved upwardly. The said means
i5 a thrust plate 22 mounted adjacent the plate 15 on
a frame member 23 of the valve. The thrust plate 22
and stationary plate 15 have coplanar slide plate con~
tact surfaces 24, 2$.
~ he valve mechanism will now be described with
particular re~erence to Figs. 2 and 3~
The actuating mem~er 20 for the slide plate 16
lS pexforms two functions. First, it blases the slide
plate 16 again~t~the stationary plate 15, thanks to
spring means 25 acting on the actuating member. Secondly,
it operates to displace the slide pla~e 16 when an
actuator 26 is suitably energis2d. The actuator member
20 is a beam forming part of a linkage 28 so designed
that the lower end of the actuator member moves in a
vertical path as the actuator 26 is operated.
As illustrated, the actuator m~mher 20 is
inclined ~o the vertical~ and to frame member 23, and
has its ~ower end copuled to the slide plate. The
coupling comprises a pin 30 which is received in a yoke
31 forming part of a shoe 32 mounted in a recess 33 in
the slide plate 16, see ~ig. 3.
At an intermediate point along its length, the
actuator member 20 is pivotally secured to a lever 34
fast with a pivot shaft 35 journalled to a second frame
member 36 ~f the mechanism.
~he actuating member 20 extends beyond lever
34 and has its upper end 38 coupled to the frame member
23. The sprins means 25, which constitutes a spring
link~ couples the beam to the frame member 23 by way of
a lever 39 and toggle arrangement ~0, to be descri~ed.
The spring means is pivotally connected at its opposite
ends to the lever 39 and end 38, respectively.
The spring means 25 is a de~ice comprising a
multiplicity of compression springs, e.g. ten or twelve,
which are threaded on a corresponding plurality of
bolts holding a paix of thrust plates 42 together. The
thrust plates 42 each have a projecting eye or clevis 43
by whi~h the ~pring means i5 secured to lever 39 and the
en~ 38, In the operative condition shown in Fig. 2, the
spring means is in a state of compression, and tends
to rotate the activating member 20 anticlockwise about
its pivotal connection with lever 34. Thu~, the lower
- 25 end of the actuating member 20 is biased towards the
- 6 -
~aphole, and the slide plate 16 is thrust into firm,
sealing contact with the s~ationary plate 15.
The spring means 25 could include a set of
Bellville washers instead of coil springs if desired.
For displacing the slide plate between its
open (raised) and clo~ed (lowered) positions, the
actuator 26 is link~d via a crank 46 to the linkage 28.
The crank 46 is fast at one end with the shaft 35 on
whlch the lever 34 is also fast. ~he actuator 26 is
pi~oted to the opposite end of the crank 46 and when
this end is disp1aced upwardly, the shaft 35 is rotated
clockwise and with it lever 34. This action serves to
displace the actuator member 20 and the slide plate 16
upwardly~ to open the valve.
As shown in the drawings, the actuator 26 is
an hydraulic or pneumatic ram. This has its piston rod
47 pivoted to the crank 46 and its body 48 remote from
the piston rod pivot~d to a lug 49 on the frame member
23.
~se of such an actuator is conYentional in the
sliding gate art, but other actuators could be substi-
tuted. For instance, the crank 46 could be actuated by,
or even replaced by, an appropriate manual control lever.
The linkage 28, comprising actuating member
20, lever 34 and spring means 25, acts approximately as
a parallel motion devicel The geometry:of lever 34 and
spring means 25 is such as to constr~in the actuating
member 20 ~o move substantially parallel to itself. By
this means, the lower end o the actuator moves vertically
with the slide plate and changes in thrust which it
exerts upon the slide plate 16 are kept within safe
bounds as the latter is moved vertically by the actuating
member 20.
The spring means 25 acts as a swing link in thP
linkage 28. It swin~s, in the same direction as the
lever 34, about an anchorage 51 at the free end of lever
39 whi~h is pivoted at 52 to the frame member 23. In
normal use, however/ the lever 39 is barred from pivoting
about the pivot at 52 by the toggle arrangement 50. The
effort developed by the spring means 25 tends to rotate
lever 39 anticlockwise about 52. Such rotation is
prevented, however, by the toggle 50 acting as a rigid
brace between the lever 39 and rame member 23, thanks
to the toggle bearing against a stop 53. Overcentering of
the toggle would be necessary if the lever 39 were ~o
move in the opposite direction abou~ ~2, so this movement
is resisted and moreover is positively prevented by a
removabIe safety pin 54. In normal usage the parts retain
the configuration æhown in Fig. 2, when the anchorage 51
is fixed.
-- 8 --
~2~8~
On occasion, it will ~e necessary to replace
one Gr bo~h the plates 15, 16. The spring-developed
thrust on plate 16 normally exceeds 5 tonsV in the
valve-closed setting and must be released for servicing.
This is ac~omplishPd by freeing the anchorage 51 by
manipulation of the toggle 50. ~irst, the safety pin
54 is removedO .Then, crowbars ~5 are l~cated in bosses
56 at the ends of a rod passing through the centre of
the toggle 50, and forming the centxe pivot thereof.
Thereafter the crowhar~ are levered so as to overcentre
the toggle 50 and allow the lever 39 to swing anticlock-
wise about its pivot at 52. ~his movement is accompanied
by relaxation of the spring means 25, which can then
for convenience be discolmected from the anchorage 51.
Having xeleased the spring biasing in this way, the
actuating memDer 20 can be swung away fxom the valv~
allowing clear access theretor Restoration of the spring
biasing is in substance a reverse of the forPgoing steps,
as will be recognised.
In the present embodiment, the linkage 28 only
approximates to a parallel motion device. This is
since the connect.ions between the actuating member 20,
the lever 34 and spri~g means 25 do not move in arcs of
equal radius a~out centres through the shaft 35 and
anchorage 51. The geometry of the system, that is the
_ g _
respective lengths of lever 34 and spri~g means 25
coupled with the positions of their swing centres
through 35 and 51, act o mi n; m; se changes in the oblique
attitude of the actuating member 20 as ~he actuator 26
is extended or contracted. As a result, the biasing
thrust acting on the slide plate changes but only within
safe limits and is at a m~ m when the valve 14 is
closed~
Example
lG A specific example of the geometry of a tap-
hole valve system according to this invention is
presented in Fig. 4 of the drawings.
In this example, the val~e slide plate has a
diameter of the order of 335 mm and a throw, or travel
o~ 320 mm between valve open and valve-closed settings~
The spring means 25 comprises twelve compre-
ssion coil springs, is 385 mm long ~hen relaxed and 360
mm long when compressed. The load on ~ach spring is
9~0 lbs (431 kg) and the springs push the thrust plates
43 apart with an aggregate force of 5 tons (5080 kg)~
With the left hand face A of ~rame member 23
and the centreline B o the pouring passage as datums,
the mechanism has the following dimensions:
-- 10 --
~L2~
- The distance between the two pivot axes of
lever 34 is 63~ mm and pivot axis through
shaft 35 is centred 600 mm above R and 214 mm
to the righ~ of A;
- in the normal operative condition, the pivot
axis through the anchorage 51 is centred
1116 mm above ~ and is 332 mm to the left of A;
- pivot point 52 o lever 39 is situated 80 mm
to the left of A and 1368 mm above B;
- the toggle 50 is connected by a pivot pin to
a lug S8 fast with the frame member 23; the
pin i5 cen~red 80 mm to the left of A and
1017 mm above ~ The connection between the
toggle S0 and the lever 39 is 248 mm from pivot
point 52, the distance between the latter and
the centre of the fixed anchorage being 356
mm. The links of the toggle each have their
two pivot apertures 125 mm apart; and
- the a~tuator member 20 is 1100 mm long, the
lever 34 being pivoted thereto at a centre
580 mm from the centre of the attachment of
spring means 25 thereto and 520 mm from the
pin 30 coupling the actuating member 20 to
the slide plate 16; the pin 30 is centred
170 mm to the left of A.
. . .
~2~
In operation, when the lever 34 i5 swung
clockwise or anticlockwise on the shaft 35, the actuating
mem~er 20 is displaced substantially parallel to itself,
the motion of its lower end being confined to a vertical
5 planeA The pivotal connection between the lever 34 and
the actuating member moves along arcuate path C, while
the pivotal con~ection between the spring means 25 and
the actuator moves along the approximately parallel
arcuate path D.
The force exerted by the spring means 25 on
the actuating member 20 normal thereto is at a maximum
in the valve-closed settiny. When the valve is opened,
the normal resolved force falls~ owing to the swinging
motion of the spring means 25 about anchorage Sl
reducing the angle between the spring means and the
lon~itudinal axis of the actua~ing member 20. I~
follows that the force applied in a direction normal to
this axis by the actuating member 20 on the slide plate
16 similarly drops as the valve 14 is opened.
The following tabulation gives the forces
applying as the slide plate is raised from its valve
closed setting (1) to the limit of its travel (9),
through e~Jenly-spaced intermediate positionsO
- 12 -
Position ~orce of sprin~ ~orcc no~mal Thrust on sl ~.de
means on to actuatine pla~e resolved
actu~tin~ mem~er eY.ert- normal thc~ctc.
member norm~l ed on slide
thereto plat~
Tons kg T~ns Icg Tons kg
9 2 o ~9263~1. 2 . ~2936 ~ . 6~26~2
8 3~153200 3.51 ~5~;~ 3.15 32~,~
7 30603657 4.û2 4084 3055 3607
6 3. 984043 ~.44 4511 3090 3952
4~3~4409 4o~4 1l0~7 J~.25 4-~ 8
4 4. 604674 5.13 ~i'12 4 o 504~72
3 4.744E~16 5.2~ 5375 4.5~ 473~
2 4.854g28 5~41 54g7 4.80 4~77
4.~ 5019 ~51 5598 4095 4~63
In this example, the mechanical advantage of
the actuating member 20 is 580/520 of 1.115.
From the foregoing it will be appreciated that
the means for biasing the slide plate 16 into sealed
contact with the stationary plate 15 and the means for
drawing the slide plate 16 aside to open the valve 14
are disposed to one side of the mechanism, and to one
side o the pouring passage. The valve arrangement
commends itself for any situation where space to one
side of a pouring passage is limited. Thus, use of the
- 13 ~
arrangement is not confined to furnace taphole control.
Various modifications will be apparent to the
addressee. For example, the actuator could act other-
wise than through lever ~6 and ghaft 35 for displacing
the linkage 28. Thus, as one possibility the actuat3r
could be coupled to the pin 30. In principle, the spring
means 25 could act on the actuating member 20 at any
poi~t thereon between lever 34 and the slide plate 16,
the spxing means then functioning in tension. The
positions of the lever 34 and the spring means could
~hen be interchanged.
: In the specific embodiment the linkage is 50
designed that the bottom end of the actuating member
20 travels vertically. In a modification, the linkage
lS 28 could be replaced by a v~rtically-extending guide
in which the bottom end o~ the actuating m~mber 20 ~oves.
The urnace/valve arrangement has the ~alve 14
and its mechanism located between the ~urnace wall 70
and the trough 21, the valve being connected by suitable
ducting to the furnace taphole. Attachment of the
valve mechanism to the furnace wall can be accomplished
in various ways and no description of the attachment
appears warranted here.
~ 14 -
