Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to machines for centrifugally
casting iron pipes and more particularly to devices in said machi-
nes for cooling the casting moulds of the type comprising cooling
liquid or water spraying systems throughout the length of the
mould.
The Applicant has found that after one or more castings of
iron certain regions of the mould may be abnormally hot notwith-
standing a theoretically uniform distribution along the mould of
the jets of water issuing from the spraying systems. Now, it is
known that the iron cast in the mould acquires after cooling~a
structure which depends on the rate of this cooling and therefore
on the temperature of the mould. This structure consequently has
~ heterogeneities corresponding to the abnormally hot regions of
v~ the mould.-~In particular, the degree of graphitization of the -
iron may be higher in the relatively colde-r regions. Consequently,~
some of the pipes cast may have to be rejected.
- - The same remarks apply to the case where the moulds are -~
- provided internally with a refractory lining containing a mix-
- ture of sil-ica and bentonite : this type of lining which is termed
a "wet spray" and permits avoiding the necessity of an annealing
- of the pipe after casting, is also affected by the degree of uni-
formity of the mould temperature.
An object of the invention is to provide a device for
cooling a mould for centrifugally casting iron pipes by spraying
-water which overcomes in a simple manner the local varia ffi ns in
temperature of the mould and permits, in the case where the mould
is provided with a "wet spray" coating, achieving a uniform
quality of this coating.
According to the invention, the invention provides a cooling
device of the aforementioned type further comprising at.least
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one guide bar parallel to the mould on which there is slidably mounted
at least one slide whose position is adjustable along said bar for
each casting and stationary during the casting and which carries an
additional local cooling water spraying element.
With this arrangement, it is possible to employ the cooling
by spraying of water with excellent results as concerns the quality
of the pipe cast.
Further features and advantages of the invention will be
apparent from the ensuing description given merely by way of example
with reference to the accompanying drawings, in which:
Fig. 1 is a diagrammatic view, partly in section, of a cen-
trifugal casting machine equipped with a cooling device according to
the invention;
Fig. 2 is a cross-sectional view, taken on line 2-2 of Pig. 1,
of the cooling device which is shown in its operative position;
Fig.3 is a partial view similar to Fig. 2 in which the
cooling device is shown in its withdrawn position of rest, and
Fig.4 is a sectional view of a detail of the cooling device.
In the embodiment shown in the drawings, the invention is
applied to a machine M for centrifugally casting iron pipes. This
machine comprises a carriage A which is movable in translation between
a pouring channel B and an extracting device for the cast pipes (not
shown) which is located at the opposite end of a runway C for the
carriage A.
In the known manner, the carriage A comprises a casing 1
in which there is disposed a mould 2 having an axis X-X. The casing
1 comprises a lower platform 3, an arched roof 4 connected on each
side to the platform 3 by lateral walls 5. One of the walls 5 comprises
detachable panels so as to open a lateral opening 6
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which extends throughout the length of the casing (Fig. 3).
The mould is supported by rolling rollers 7 which are
driven in rotation by a motor 8. The assembly can be
moved in translation along rails 9, defining the runway ~,
by a pneumatic jack (not shown).
Three water spraying systems 10 whose length
corresponds to that of the mould 2 are disposed longitudi-
nally in the casing 1 in the vicinity of the outer surface
of the mould. Two of these systems are located above the
mould on each side of a vertical plane containing the
axis X-X and the third system is disposed under the mould
in this vertical plane. The systems 10 are provided at
- their`ends with wate^ inlet and oulet-pipes which are
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~ detach~bly connected by flanges 12 to pipes 13 which ex-tend
through the wall of the casing and are connected to a
water supply pipe.
The casing 1 also carries in its lower part
a longitudinally-extending guide bar 14 laterally disposed
in the vicinity of the detachable lateral wall 5 parallel
to the axis X-X and to the spraying systems 10. The
guide bar 14 has, for example, a square section and is :
rotatable about its axis in end support bearings 15. It
can be maintained in different angular positions by means
of a pin 16 which extends through a ring 17, fixed to
each end of the bar 14, and through a fixed plate 18
secured to the platform 3 (Fig. 4). A pin 16, a ring 17
and a plate 18 are provided near each bearing 15. Each ring
17 has at least two diametral apertures 19 which afford
different angular orientations for the pin 16 so that it
is possible to ~ive the guide bar 14 at least two
orientations. Slidably mounted on the bar 14 are two
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slides 20 having a section corresponding to the section
of the bar 14, that is to say a hollow square section. Each
slide 20 carries a rigid upright pipe 21 provided at its
upper end with an additional local water spraying element
22. The latter is constituted by a short pipe which extends
in a direction parallel to the axis X-X of the mould 2 and
carries a plurality of spraying nozzles or jets 23. In the
operative position shown in ~ig. 2, this spraying pipe is
slightly above the axis X-~ of the mould and near to the
surface ~f the latter, the jets 23 being directed toward
this surface.
Communicating with the rigid pipe 21 is a
rigid bent pipe 24 for connection to a flexible supply
pipe or hose-25 wound into a number of coils 26 which are
hooked to the upper wall 4 of the casing by means of
a rod 27. The hose 25 is connected to the rigid pipe 24
by a special connection 28 of known type which is rapidly
assembled and disassembled and closes automatically when
disassembled. The hose 25 extends through the upper wall 4
of the casing in the vicinity of the middle of the leng~h
of the latter and is connected to a rigid pipe carrying a
valve 30 for regulating the rate of flow. This valve 30
is secured to a T-coupling 31 whose main branch is connected
to a main water supply pipe 32.
The pipes 11 supplying water to the spraying
sys~ems 10 are also connected to this main pipe 33 (Fig. 3).
The distribution of water is common to the main systems 10
and to the additional water spraying elements 22 and is
controlled by the same valve in the main pipe 32 (not
shown). In other wordsl the opening and closin~ of the
valves dispose~ in the main supply pipe supplies water and
stops the supply of water in respect of both the systems 10
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and the additional supply elements 22. The latter are also
controlled by their respective val~7e 30.
The lower platform 3 of the casing 1 is
provided with short pipes 33 for draining the cooling water
sprayed onto the mould by the systems 10 and the additional
water supply elements 22.
The device just described operates in the
following manner :
When, for example,excessively red zones are- - :
noticed on the pipes which have just been extracted, this
: indicates that there is one or more abnormally hot zones in
the mould 2 (which may or may not have a refractory lining)
and the slides 20 are shifted along the guide bar 14 until
.the additional spraying elements.22 are disposed in facing -
relation to these zones. In the course of this displacement,
the flexible coils 26 more toward or away from each other
to suit~the required length. Wit~Z the mould 2 in rotation,
the water is admitted both to the systems 10 and to the
additional supp~y elements 22. By actuating the valves 30
- 20 water can be supplied to one or the other of the two additional
-water supply elements 22. When there are no abnormally hot
zones, the water supplied to the eIements 22 can be simply
closed.
i The mould 2 is consequently sprayed not only
by the systems 10 but also by the additional supply elements 22
; which thus afford an additional local spraying and conseaZuently
a local more pronounced cooling of the abnormally hot zones.
Thus the iron cast in the mould 2 comes in contact with a
mould wall or mould lining at a roughly uniform temperature
and solidifies with a uniform structure.
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At rest, the rapid couplings 28 can be
uncoupled after having withdrawn the lateral panels of the
casing. These couplings automatically close the associated
- pipe. The couplings 28 ~re hooked to the upper wall 4 of
the casing by a suitable hook tnot shown).
After the pins 16 have been removed, the
guide bar 14 with the pipes 21 carrying the spraying elements
22 can rotate to a completely withdrawn position (Fig. 2)
in which the pipes 21 bear against the lower edge of the
opening 6 of the casing. In this position of rest of the '
device, the lateral opening 6 is open and, after having if
desired disassembled the spraying systems 10, the opening 6
offers a passage for laterally withdrawing the mould 2
through the opening 6.
If the mould 2 is replaced by a mould of
larger diameter, the bar 1~ and its rings 17 are left in à
position of the additional spraying devices which is slightly
further away from the axis X-X than that shown in Fig. 2,
by employing another locking aperture in the rings 17. Fig. 3
shows in full line the inoperative position of rest of the
devices and in dotted lines the two possible operative
positions 22a and 22b of the devices. Thus the bar 14,
ring 17 and the locking pins 16 enable the mould spraying
distance to be adjusted for the devices 22 in accordance
with the diameter of the mould 2 and also allow the complete
retraction of the devices 22.
By way of a modification, two guide bars 14
may be provided on each side of the mould 2, the second
additional,spraying assembly being identical to the first
assembly shown in Fig. 3 and symmetrical with respect to the
first as,sembly. The two assemblies are supplied by the same
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flexible pipe 25, which terminates for example in a tubular
yoke or breeches pipe connected through a rapid coupling 28
to each bent pipe 24 located on each side of the mould 2.
Also, instead of being square, the section of
the guide bar 14 may be polygonal or round and provided
with a groove similar to a keyway in which slides a pin
mounted on the slides 20 which are in the form of c1rcular
rings.
Also instead of completely surrounding the bar
14, the slides 20 may have an open cross section. It will be
understood that, if necessary, the slides 20 may be provided
with a set screw for locking the slides in position on the
bar 14. A number of slides other than two may be provided
on each bar 14.
An advantageous arrangement consists in
providing the end of the pouring channel B with an external
photoelectric cell 34 which is responsive to infrared rays
and capable of detecting abnormally hot zones in the mould.
This cell 24 is connected by transmission lines 35 and 36,
shown in dot-dash lines in Fig. 1, to electrically-operated
valves which replace the valves 30 so as to open the valves
selectively in the known manner in the event of excessive
heat which is manifested by an abnormally high infrared
radiation. In this case the procedure is as follows :
When the operator notices on the pipe just
extracted from the mould the repeated existence of one or
two abnormally red zones, he disposes the slides 20 in a
corresponding manner. When in the course of the rearward
travel of the carriage before each following casting, the
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mould 2 being driven in rotation, the cell 34 scans the
ent~e inner surface of this mould, as long as the examined -
zones are abnormally hot the cell commands the opening of
the corresponding electrically-operated valves.
In a modification of this arrangement,
corresponding to the case where a "wet spray" is sprayed
into the mould by means of a gun carried either laterally
by the pouring channel or by an additional rod, the cell 34
is associated with this gun in such manner as to move it
away from the end of the pouring channel. Indeed, the
radiation from the molten iron diminishes the sensitivity
of the cell.
In accordance with a simplified arrangement,
this cell may also be simply connected to a panel of light
signa~ so as to indicate to the operator that he must actuate
the additional water supply elements 22. In this case no
electrically-operated valve is employed, but the valves 30
- shown in Fig. lj and the operator actuates them by hand when -
required.
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