Note: Descriptions are shown in the official language in which they were submitted.
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B~CKGROUND OF THE INVENTION
This invention relates generally to the c~ntrol of material flow and
more particularly ~s concerned with controlling the flo~ of material
such as ore, rock and mud through an ore pass on the mines,
Mbterial of the kind described is in many instances channelled
through chutes and the flow of material through such a chute is
controlled by means of a door. Under certain conditions, when the
flow rate of the material is extremely high, it becomes difficult if
not impossible effectively to operate a chute door. The excess
material can flood the haulage, i.e. the tunnel or passage beneath
the chute and the chute operator is thereby exposed to acute danger.
Apart from leading to fatalities excess material flow of the kind
described, referred to as a rush, blocks the haulage and can
severely hamper production.
SU~ARY OF THE INVENTIûN
The invention provides a method of controlling material flow through
a passage which includes the steps of mouing a door, which is
positioned at a first location in the passage, thereby to recgulate
the rate of material flow through the passage, and of allowing the
door to be movecl by the material, when its flow rate exceeds a
predetermined level, to a second location in the passage at which
the door substantially reduces the material flow rate through the
passage.
The door, at the second location, may reduce the material flow to
less than 20% of the maximum possible flow rate through the passage,
or may substantially seal off the passage to material flow. In a
preferred form of the invention the flow rate is reduced to between
5% and 20% of the maximum possible flow rate and suitably to the
order of 15%.
The first location may be at or near an inlet end to the passage,
and the second location may be at or near an outlet end from the
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passage, or vice versa.
The invention also provides a method of controlling material flow
through a passage which includes the steps of using a movable dDor
to regulate the rate oF material flow through the passage, and> when
the rate of material f low through the passage reaches a
predetermined level, of allowing the door to be moued by the
material to a position at which the door substantially reduces the
rate of material flow through the passage.
The invention further extends to apparatus for controlling material
flow which includes a housing in which is formed a passage through
which the material passes, and at least one door which is located in
the passage, the door, at a control position, being movable by means
of a control device to regulate the rate of material flow through
the passage, the door further being movable by the material, when
the rate of material flow through the passage reaches a
predetermined level, to a blocking position at which the door
substantially reduces the rate of material flow through the passage.
The control device may include a handle which is engaged with the
door, the apparatus including means for disengaging the handle from
the door when the door moves to a predetermined position. This means
may take the form of a cam or similar device which effectively
displaces the handle from an operative position at which it can
cause door movement, to an inoperative position, when the handle and
the door are moved to a predetermined orientation relatively to the
housing,
The door may be mounted for rotation in the passage about an axis,
e.g. on one or more axles, or alternatively, the door may be mounted
on guides such as rollers which permit the door to be moved along a
predetermined path.
The housing may be formed with at least one removable closure
through which material can be extracted from the passage. This
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closure may for example be loGated on an upper side of th~ housing
or, alternatively or additionally~ on a lower ~ide of the housing.
The closure could also be on a side wall of the housing.
Preferably the door, in cross-section, has a shape which is at least
partly arcuate and, in the oon~rol position, presents a ~ace which
is at least partly convex to oncoming material flow through the
passage. The door in the blocking position may then present at least
a partly concave face to oncoming material flow.
The door may include means which is adapted to react with the
material, at least when the rate of material flow reaches the
predetermined level, thereby at least to assist in generating force
for causing mouement of the door to the blocking position. The means
may be provided at least on a face of the door. This means may
comprise at least one member or formation on the face. For example,
in one form of the invention, the means consists of one or more fins
or ribs or similar raised formations on a face of the door. The fins
may extend generally parallel to an axis about which the door is
rotatable. In a different form of the invention one or more members
are suspended from a face of the door. These members may consist of
chains, cables, rods or the like which are so positione~ that when
the door reaches a predetermined orientation, consistent with a
maximum flow rate of material through the passage, the material
impinges on them and thereby causes a force to be generated which
causes closure of the door. This face of the door may be at least
partly concave.
The invention further extends to apparatus for controlling material
flow which includes a housing in which is formed a passage through
which the material passes, at least one door which is mounted for
rotation, at least to a limited extent, in the passage, and means
for moving the door, the door including an outer face which is at
least partly convex and which is presented to oncoming material flow
through the passage, and an inner face which is at least partly
concave and which has one or more formations or members adapted to
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engage with the material passing through the passage, when the door
reaches a predetermined orientation relatively to the housing,
thereby to cause the door to be moved to a position at which
material flow through the passage is substantially reduced.
s
In a variation of the invention the apparatus includes a passage in
which is formed a housing through which the material passes, and a
door which is mounted in the passage for rotation about an axis
which is substantially transverse to the direction of material flow
through the passage, the door being rotatable from a first position
at which a first side of the door is presented to oncoming material
flow through the passage to a second position at which the first
side generally faces in the direction in which material flows from
the passage.
The door in cross-section is preferably susbtantially arcuate and
the first side is convex.
The door may be rotatable through approximately 1B0& when moving
between the first and the second positions.
SRIEF DESCRIPTION OF THE DRAWINGS
The invention is further described by way of example with reference
to the accompanying drawings in which :
Figure 1 is a side view of apparatus according to the invention with
a door in a controlled, closed position;
Figure 2 is a side view of the apparatus of Figure 1 with the door
in a blocking position;
Figure 3 is a plan view of portion of a handle used on the door of
the apparatus of Figure 1; and
Figure 4 is a side view of the handle shown in Figure 3.
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DESCRIPTION OF PRE~ERRED EJYlBODIlflENT
Figures 1 and 2 illustrate apparatus according to the invention for
controlling the flow of material through an ore pass. The apparatus
includes a housin~ 10 and a door 12 which is mounted in the housing.
S The housing includes 8 flange 14 whereby the appara~us can be
installed in a chute in the ore pass. This aspect is not important
for an understanding of the invention and therefore is not further
elaborated on.
10 The housing 10 defines a passage 16 which has an inlet 1B and an
outlet 20. The housing has a domed closure 22, on its upper surface,
which is pivotally attached to the remainder of the housing. On the
upstream side of the closure the housing includes an inspection
cover 24 which is fixed to the housing by means of hinge 26.
15 Normally the inspection cover is kept closed by means of an adeguate
locking device, not shown.
A deflector 2B is positioned between the inspection cover 24 and the
closure 22, on the inner face of the upper surface of the housing.
20 The housing has side walls 30 and opposing registering holes 32 are
formed in the side walls on the upstream side of the door 12.
A second closure 34 forms part of the lowermost wall of the housing.
25 The door 12 includes a partly convex outer face 36, an inner face 3B
of complementary concave shape, ribs 40 which are welded to the
inner face 3B, and side walls 42 which are engaged with stub axles
44 which extend through the side walls 30 of the housing. The axles
are mounted on bearings 46 secured to fixed structure 4B on the
30 outer surfaces of the side walls 3û, see Figure 4.
A handle 50 is fixed to one of the axles 44 (see Figures 3 and 4).
The handle includes an inner portion 52, and an outer portion 54,
which are interconnected by means of a hinge 56. A support member 58
35 is also fixed to the axle and underlies the handle 50. The support
menber carries a length of channel section 60 which has side walls
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62 between which the handle 50 is positioned.
The support 5B ~as a hole 64 and the handle 50 has a proiection 66
which is ~ngageable with the hole.
s
The support 58 has a pin 68 fixed to it. A spring 70, engaged with
the pin, biases a washer 72 towards the support member 5B. The
movable portion 54 of the handle has a slot 74 which is engageable
with the pin. With the components so engaged the spring 7û exerts a
biasing force on the movable portion of the handle which ensures
that the mouable portion remains positioned in the channel 60 and,
in addition, the projection 66 remains engaged with the hole 64.
Under these conditions rotational force may be applied to the door
by means of the handle.
A cam 76 is mounted on one side wall 30. The cam has an active
surface which is inclined and which is positioned so that when the
handle 50 reaches a predetermined orientation relatively to the
housing, the cam surface acts on the movable portion 54 and
displaces it outwardly away from the side wall of the housing. This
movement is aga:;nst the biasing action of the spring 50 and it
causes the projection 66 to disengage from the hole 64 and the
movable portion 54 to disengage from the channel 60. The h-nge 56
allows this movement to take place. At this position the handle
therefore becomes inoperati~e.
Figure 1 shows the apparatus of the invention with the door 12 in a
controlled closed position at which it blocks the inlet 1B. A lower
edge of the door contacts a bottom wall of the housing at a point B0
snd in this way further rotation of the door about the axles 44, in
an anticlockwise direction, is prevented. The door is movable from
the controlled closed position shown in ~igure 1 by means of the
handle 50 so as to allow material to pass from the inlet 18 through
the passage 16 and to the outlet 20 in a regulated manner. The door
is opened by causing it to rotate in a clockwise direction about the
axles 44. This operation is completely under the control of an
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operator.
It sh~uld be pointed out that the handle 50 can be manually
controlled or alternatively use can be made of mechanical means, for
example a hydraulioally or pneumatically operated cylinder, to move
the handle~ The construction of the handle shown in Figures 3 and 4
is of course not restrictive for a similar working operation can be
Gbtained with other structures. If material flow through the passage
becomes excessive, for any reason, then an operator will naturally
attempt to close the door end so restore it to the Figure 1
position. If the force required for this operation is too high, and
it is not possible to close the door, then the material flow in fact
forces the door fully opened to a position at which the outer face
36 substantially uniformly opposes the closure 22. At this stage the
door is so orientated that material passing through the passage 16
impinges on the outer ends of the ribs 40. The ribs are so situated
on the door that the material flow in fact causes the door to rotate
further clockwise. In this way a greater area of the ribs is brought
into contact with the material passing through the passage and the
door is rotated more forcefully and more rapidly further clockwise
until it reaches the Figure 2 position at which a lower edge of the
dDor again contacts the lower wall of the housing at a contact point
B2. Further rotation of the door in the clockwise direction is
therefore effect;ively stopped and the flow rate of material through
the passage is s~stantially reduced. To avoid undesirable pressure
build ~p the trailing edge of the door is in fact shaped and
orientated so that a passage 84, of substantially reduced
dimensions, is formed between the door and the closure Z2. This
permits material to flow through the housing at a reduced rate.
Preferably this rate is between 5% and 20% of the maximum flow rate
of material and generally is of the order of 15% of the maximum
possible flow rate. Stated otherwise the passage ~4 permits the flow
of approximately 15% of the material that would otherwise flow
through the apparatus.
When the door is ~orced fully open by a sudden rush of ~aterial the
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handle raturally rotates together with the door. Under excess flow
condit;ons the door is caused to move very rapidly and the handle
similarly travels at high speed. The handle itself is dangerous~ to
an operator and cause harm. It is for this reason that a handle
eonstruction Df the kind shown in Figure 3 and 4 is employed. When
the door reaches a fully opened position, which is indicative of
excess flow rates, the cam 76 causes disengagement of the handle
from the door so that the handle is left in a harmless position
whilst permitting free movement of the door.
The apparatus of the invention thus effectively and automatically,
under excess flow rate conditions, operates to shut off~ or at the
very least reduce, the material flow.
With the door in the Figure 2 position jumper bars or the like are
passed through the holes 32 in the side walls 30 to provide a
barrier which restrains movement of the material in the housing. The
closure 22 may then be uncoupled and opened so that the material
inside the passage 16, in the region of the door, can be manually
removed. The lower closure 34 may also be removed to assist in the
clearing operation. Thereafter the door is restored to the Figure 1
position and the bars are removed so that material can again flow
through the apparatus in a controlled manner.
The inspection cover 24 permits the interior of the housing to be
viewed and inspected, even under working conditions.
The deflector 2B is useful under certain conditions, for example
when an elongate object flows through the passage, for it causes
such objects to be forced downwardly towards the base of the
housing, and in this way the likelihood of the operation of the door
being fouled is minimized.
The door has been shown as being mounted on axles 44. It is possible
to mount the door on rollers, runners or other guiding mechanisms
which cause the door to move along a predetermined path. In this
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case the ~xles are dispensed with. It is also possible to ~ount the
door so that its side walls are effectively outside the sid`e walls
of the housing and not inside as shown in Figure 1. With this form
of the invention the side walls of the housing have cùt outs and the
side walls of the dDDr are effectively larger in size so that they
overlap and provide a seal for the cut outs.
Another modification which can be made to the apparatus of the
invention is to replace the ribs 40 with chains, cables, rods or the
like which are suspended from the conc~ve inner face 3~. When the
door reaches its fully opened position these members are orientated
su~stantially in the same direction as the ribs and therefore engage
with the material flow, in the manner described, thereby to cause
the door to close. It is also possible to shape the door itself so
that this type of action is achieved and th;s modification,
particularly, is intended to fall within the scope of the present
invention.
