Information
-
Patent Grant
-
6192971
-
Patent Number
6,192,971
-
Date Filed
Wednesday, December 23, 199825 years ago
-
Date Issued
Tuesday, February 27, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
-
CPC
-
US Classifications
Field of Search
US
- 164 421
- 164 464
- 164 465
- 164 483
- 164 484
-
International Classifications
-
Abstract
A sealing device for a casting table of a machine for the continuous vertical casting along a vertical extraction axis (X—X) of cast iron pipes (T) includes a die block (5) aligned with the vertical extraction axis and a device (3) for the supply of liquid iron. Two sealing gaskets (12A, 12B) are located between the outlet from the device supplying liquid iron and the entry to the die block. The sealing device has members (6, 15, 21) for tightening the die block against the outlet of the supply device, parallel to the vertical extraction axis, in order to tighten the sealing gaskets.
Description
BACKGROUND OF THE INVENTION
This invention relates to the casting of molten metals, and more particularly the continuous vertical casting of metal parts, in particular pipes, of cast iron. Although it applies to the casting of different types of metal parts, it is particularly advantageous for the casting of thin-walled cast iron pipes. The expression “thin-walled pipes” applies to pipes of small thickness/diameter ratio, less than 10%, rather than the thickness considered by itself in isolation.
The invention relates more particularly to a machine for the continuous vertical casting along a vertical extraction axis of cast iron pipes comprising a die block aligned with the vertical extraction axis and a device for the supply of liquid iron feeding the die, a machine in which at least one sealing gasket is located between the outlet from the supply device and the inlet to the die.
In order to ensure a satisfactory seal at the gasket or gaskets it is necessary to apply a certain tightening force to them parallel to the axis of extraction of the pipes. This force should act against the force extracting the pipes in order to compress the sealing gaskets and thus ensure a seal for the whole.
When a casting machine is brought up to steady state conditions, the various materials in contact with the liquid metal expand by different proportions according to the material. This expansion affects the tightening of the sealing gaskets, so the gaskets can be damaged and/or the seal for the liquid metal may be lost.
Difficulties of the same kind may result from creep of the gaskets over time, and also their adhesion to the pipe die during the course of manufacture.
SUMMARY OF THE INVENTION
The purpose of this invention is to overcome these various disadvantages by providing a casting machine in which a seal for the liquid metal is ensured during both the stage during which steady state conditions are attained and the stage of operation at constant high temperature.
In order to achieve this the invention relates to a sealing device for a casting table of a machine for the continuous vertical casting along a vertical extraction axis of parts, in particular pipes, of cast iron, the casting table comprising a die block which is aligned with the vertical extraction axis and also a device for supply of liquid iron feeding the die block, at least one sealing gasket being located between the outlet of the device supplying liquid iron and the die block, characterised in that it comprises means for tightening the die block against the device for the supply of liquid metal with a constant force, parallel to the vertical extraction axis, in order to tighten the sealing gaskets.
The sealing device for the casting table of the casting machine according to the invention may incorporate one or more of the following features:
the tightening means comprise a support for the die block which can be moved along an axis substantially parallel to the vertical extraction axis, a frame on which the device for the supply of cast iron is mounted, and at least two fluid-operated jacks regularly distributed around the die block, each jack being attached to both the said support and the said frame, and each jack being connected by means of a fluid conduit to a unit controlling the tightening force from each jack,
the fluid conduits for the jacks are joined together into a common fluid conduit, and this common conduit is connected to the unit governing the tightening force.
the fluid-operated jacks are hydraulic jacks,
the fluid-operated jacks are pneumatic jacks,
the bodies of the jacks are entirely located outside the space between the two horizontal planes bounding the induction coils.
The invention also relates to a casting table for a machine for the continuous vertical casting of parts, in particular pipes, of cast iron along a vertical extraction axis (X—X), the casting table comprising a die block aligned along the vertical extraction axis (X—X) and also a device for the supply of liquid iron feeding the die block, at least one sealing gasket being located between the outlet from the device for the supply of liquid iron and the die block, characterised in that it comprises a sealing device as defined above.
BRIEF DESCRIPTION OF THE FIGURES
Other features and advantages of the invention will become apparent from the following description which is given by way of a non-restrictive example with reference to the appended drawings in which:
FIG. 1
is a view from the side of a casting table according to the invention with a first cut-out at the inlet to the device for the supply of liquid iron and a second at the outlet from that device,
FIG. 2
is a view of the casting table from above, in the direction of arrow II in
FIG. 1
, and
FIG. 3
is a view in transverse cross-section along the line III—III in FIG.
2
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
shows a table
1
for the continuous vertical ascendant casting of parts, in particular pipes T, of cast iron. This casting device incorporates a device
3
for the supply of liquid iron and a die block
5
which is fed via its lower end by this supply device
3
. Pipe T is drawn out from die block
5
by extraction means which are not shown, in an upward direction along vertical extraction axis X—X. The direction of the extraction force is represented by an arrow F.
Device
3
for the supply of liquid iron is set on a frame
6
and prevented from making lateral and vertical movements thereon by vertical tie bars
7
and horizontal cross-members
8
. It incorporates a U-shaped siphon
9
which is constructed from cast refractory concrete in a single piece.
This siphon
9
incorporates a conduit
10
for the supply of liquid iron comprising a vertical descending part
10
A through which the molten iron enters, a horizontal part (not shown in the figures) and a vertical part
10
B through which the liquid iron departs, which is directed upwards.
With reference in particular to
FIG. 3
, it will be seen that a heating base
11
is placed between die block
5
and the outlet from siphon
9
. The seal for the molten metal is provided by two annular sealing gaskets
12
A and
12
B, a first one
12
A located between the outlet
from siphon
9
and the underside of heating base
11
, and a second
12
B located between the upper surface of heating base
11
and the underside of die block
5
.
In addition to this, siphon
9
and heating base
11
are surrounded by a shell
13
in the thickness of which induction coils
14
are embedded. These induction coils
14
are provided with electrical current by an external current generator, which is not shown, to keep the iron molten through induction beating.
Die block
5
is fixedly mounted in a retractable support
15
in the form of a platen. This die block incorporates a cooling unit
17
, which is connected to a cooling fluid circuit by means of inlet pipe
17
A and outlet pipe
17
B. Unit
17
has an extension of reduced diameter on its upper surface. This is housed in a matching housing
15
A in support
15
which has a vertical axis Y—Y and is attached thereto by means of a crown of axial bolts
15
B (FIG.
2
).
The relative position of support
15
with respect to frame
6
is determined by two short columns
18
which are directed downwards and are attached to support
15
in a diametrically opposite fashion with respect to die block
5
, as shown in FIG.
2
.
FIG. 3
shows that each short column
18
is guided into an associated socket
19
with ball-bearings, which is fixed to frame
6
.
As a result of the use of short columns
18
acting together with ball-bearing sockets
19
, the relative position of support
15
with respect to frame
6
and therefore the relative position of die block
5
with respect to frame
6
are precisely defined in a plane perpendicular to vertical extraction axis X—X, while the distance between the support and the frame can be adjusted parallel to axis X—X.
In order to immobilise the position of support
15
along axis X—X with respect to frame
6
, two fluid-operated jacks
21
, such as e.g. hydraulic jacks or pneumatic jacks, are fixed in diametrically opposite positions on support
15
(FIG.
2
). As shown in
FIG. 3
, each jack
21
comprises a rod
22
whose free end
23
is secured by a gudgeon
24
in a mounting
25
which is integral with frame
6
. Each gudgeon
24
is secured in mounting
25
by pins (not shown) so that support
15
can be easily dismantled from frame
6
. The bodies
21
A of jacks
21
are fixed to the upper surface of platen
15
by means of a collar
21
B in order to be outside the reach of the induction field generated by induction coils
14
.
As may be seen in
FIG. 1
, each fluid-operated jack
21
is connected by means of a conduit
26
,
27
to a common conduit
29
. This common conduit
29
is connected to a hydraulic unit
31
regulating the tightening force of each jack, which is shown diagrammatically. Advantageously, this hydraulic unit is also mounted on frame
6
.
Once the position of support
15
with respect to frame
6
has been immobilised by jacks
21
, the support and the frame, together with die block
5
and supply device
3
, form a rigid integral assembly. This rigid integral assembly rests on a fixed base
40
.
In order to tighten sealing gaskets
12
A and
12
B a particular tightening force is applied to the jacks by means of regulating unit
31
. The tightening force exerted on sealing gaskets
12
A and
12
B corresponds to the tightening force exerted by jacks
21
to draw mountings
25
in the direction of support
15
. Given the fact that two jacks connected to hydraulic unit
31
by a common conduit
29
are used, the tightening force applied is identical for each jack. In addition to this, once adjusted, it remains constant despite the expansion which takes place in heating base
11
, and despite creep in the gaskets and adhesion between pipe T and the die, on account of the hydraulic principle of its operation.
In addition to this the provision of tightening by means of hydraulic jacks also performs the function of a “safety fuse”. In fact, when the force extracting pipe T becomes greater than the force applied to the jacks, the components of the die block tend to come apart in the direction in which pipe T is extracted. This brings about release of the gaskets and the leakage of metal to the exterior, and the machine stops without damage to the installation for the manufacture of pipes.
Claims
- 1. A sealing device for a casting table of a machine for a continuous ascending vertical casting along a vertical extraction axis (X—X) of cast iron pipes (T), the casting table comprising:a die block (5) aligned with the vertical extraction axis, a device (3) for supplying liquid iron to the die block and, at least one sealing gasket (12A; 12B) disposed between an outlet from the supplying device and the die block, and the sealing device comprising means (15, 6, 21) for tightening the die block against the outlet of the supplying device with a constant and uniformly applied force, parallel to the vertical extraction axis to compress the at least one sealing gasket, said force acting in a direction opposite the ascending direction of pipe extraction.
- 2. A sealing device for a casting table of a machine according to claim 1, wherein the tightening means comprise a support (15) for the die block which can be moved along an axis substantially parallel to the vertical extraction axis, a frame (6) on which the device for supplying liquid iron rests, and at least two fluid-operated jacks (21), uniformly distributed around the die block, each jack being connected to both the support and the frame (6), and each jack being connected by an associated fluid conduit (26, 27) to a unit (31) regulating the tightening force in each jack.
- 3. A sealing device for a casting table of a machine according to claim 2, wherein fluid conduits are connected to a common fluid conduit (29) in turn (29) is connected to the unit regulating the tightening force.
- 4. A sealing device for a casting table of a machine according to claim 2 wherein the fluid-operated jacks are hydraulic jacks.
- 5. A sealing device for a casting table of a machine according to claim 2 wherein the fluid-operated jacks are pneumatic jacks.
- 6. A sealing device for a casting table of a machine according to claim 2 wherein bodies of the jacks are located outside a space lying between two horizontal planes which bound induction coils (14).
Priority Claims (1)
Number |
Date |
Country |
Kind |
96 08960 |
Jul 1996 |
FR |
|
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/FR97/01300 |
|
WO |
00 |
6/24/1999 |
6/24/1999 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO98/03289 |
1/29/1998 |
WO |
A |
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4506723 |
Bellocci et al. |
Mar 1985 |
|
4611651 |
Gourmel et al. |
Sep 1986 |
|
4690199 |
Gourmel et al. |
Sep 1987 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
1 357 949 |
Jul 1964 |
FR |
WO 9426444 |
Nov 1994 |
WO |