Abstrict A combination of anvils in a vertical shaft-type impact crusher
with deadstock spaces enables the extension of life of the tips
mounted on a rotor. A combination of hard tips with softer tips
overcomes the inconsistency in which the hard tips that are prone
to wear by chipping but are erosive resistant to collision with
stones of a large grain size accelerated by the rotor, while the
softer tips are resistant to chipping-wear but are ordinarily prone
to erode by collision with stones of a smaller grain size accelerated
by the rotor. Crushers having anvils and dead stock spaces, have
pairs of symmetrically arranged hard tips and softer tips mounted
on a reversibly rotatable rotor. The pairs of tips are located in
symmetry with respect to each of a number of angularly related centerlines
extending radially from the rotational axis of the rotor.
Claims What is claimed is:
1. A vertical shaft type impact crusher comprising,
a casing body (1),
a rotor (10) mounted on said casing body (1), being reversely rotatable
for giving stones supplied thereto centrifugal force,
anvils (32a, 32b, 32c, 32d) mounted circumferentially around said
rotor (10),
said rotor (10) including multiple pairs of tips (72L,72M,72N),
the respective pairs of tips including first and second tips being
located in symmetry with respect to radial axes disposed at equal
angular intervals, said radial axes extending from the rotational
axis of the rotor (10) in the radial direction,
the first tips (72L172M172N1) of each of said pairs being directed
forwardly in the rotational direction of said rotor with respect
to the respective radial axes (L,M,N) and being made of hard material
in comparison with the material of the second tips, and
said second tips (72L272M272N2) of each of said pairs being directed
backward in the rotational direction of said rotor and being made
of a softer material in comparison with said hard material.
2. The vertical shaft type impact crusher of claim 1 further comprising:
a dead stock forming plate (30) forming dead stock spaces (34a,
34b, 34c, 34d) thereon circumferentially around said rotor (10)
to accumulate crushed stone therein, said dead stock forming plate
(30) being located around said rotor (10) and having a bore (31)
in which said rotor (10) is located.
3. Vertical shaft type impact crusher of claim 2 still further
comprising:
an adjustable means for adjusting the distance between said respective
anvils (32a, 32b, 32c, 32d) and said rotor (10), said adjustable
means being located between said respective anvils (32a, 32b, 32c,
32d) and the inner surface of said casing body (1).
4. Vertical shaft type impact crusher of claim 2 or claim 3
wherein said bore (31) is circular, and still further comprising:
a ring for adjusting the the volume of said dead stock spaces (34a,
34b, 34c, 34d), said ring being replaceably mounted on the peripheral
edge of said circular bore.
5. Vertical shaft type impact crusher comprising:
a casing body (1),
a rotor (10) mounted on said casing body (1), being reversely rotatable
for giving stones supplied thereto centrifugal force,
dead stock spaces (34a, 34b, 34c, 34d) for accumulating crushed
stones therein, said dead stock spaces being located circumferentially
around said rotor (10),
anvils (32a, 32b, 32c, 32d) for crushing stones discharged from
said rotor, said anvils being mounted in the circumferential area
around said rotor (10), said anvils being located between said respective
dead stock spaces in mutually spaced disposition peripherally around
said rotor (10),
said rotor (10) including multiple pairs of tips (72L,72M, 72N),
the respective pairs of tips including first and second tips being
located in symmetry with respect to radial axes disposed at equal
angular intervals, said radial axes extending from the rotational
axis of the rotor (10) in the radial direction,
the respective first tips (72L172M172N1) of each of said pairs
being directed forwardly in the rotational direction of said rotor
with respect to the respective radial axes (L,M,N) and being made
of hard material in comparison with the material of the second tips,
and
the second tips (72L272M272N2) of each of said pairs being directed
backward in the rotational direction of said rotor and being made
of a softer material in comparison with said hard material.
6. A method for operating a vertical shaft type impact crusher
including a rotor rotatable in a casing body having stone crushing
anvils disposed at spaced locations thereabout and dead stock spaces
between said anvils, said method comprising the steps of:
providing pairs of tips on said rotor, each including a first tip
directed in one rotational direction and formed of a hard material,
and a second tip directed in an opposite rotational direction and
formed of a material softer than that of said first tip,
supplying raw stones to said crusher,
determining the grain size of said raw stones; and
rotating said rotor in said one direction or said opposite direction
in response to the grain size of the raw stones.
7. The method of operating a vertical shaft type impact crusher
as recited in claim 6 wherein
rotation of said rotor in said one direction or in said opposite
direction occurs in response to the degree of wear of said first
tips (72L172M172N1) in comparison with that of said second tips
(72L272M272N2).
Description BACKGROUND OF THE INVENTION
The present invention relates to a vertical shaft-type impact crusher
and an operation method for a vertical shaft-type impact crusher.
More particularly, the present invention relates to a vertical shaft-type
impact crusher and an operation method for a vertical shaft-type
impact crusher for crushing bulk materials, for example, natural
rock, into grains or particles of desired size.
Bulk materials, e.g., natural rock, are crushed in accordance with
various uses, for example, aggregate for concrete, paving stone,
subgrade material, etc. One type of crusher used for such a crushing
process is known as a vertical shaft-type impact crusher.
Impact crushers operate on the basis of the principle that rock
is accelerated at a high speed so as to collide with an impact surface,
thereby crushing the rock. Such impact crushers may be generally
divided into two types according to the mode of crushing: anvil-type
and dead stock-type.
The anvil-type impact crusher includes a rotor having a plurality
of wings or blades on the upper side thereof which are rotated at
a high speed, whereby raw stones east into the crusher are accelerated
by the blades and centrifugally discharged so as to collide with
anvils which are disposed annularly around the rotor, thereby crushing
the raw stones.
Such an anvil-type impact crusher is mainly used for the purpose
of crushing raw stones having a relatively large diameter by collision
to thereby reduce the size of the raw stones.
On the other hand, a dead stock-type impact crusher is mainly used
to smooth surfaces of raw stones which have already been crushed
into gravel of desired size and to make the grain size uniform.
Such a dead stock-type impact crusher is similar to the anvil-type
impact crusher in that the raw stones are centrifugally accelerated
by blades, but different from the latter in that dead stocks are
formed from crushed raw stones at the periphery of the rotor, and
the surfaces formed by this dead stock have angles of rest which
are used as impact surfaces for crushing raw stones.
Aggregate for concrete is required to be made of crushed stone
of a large grain size and crushed sand of small grain size. According
to JIS (Japanese Industrial Standard), it is required for both stone
and sand to be in given definite grain size distributions. The distribution
of Crushed Stone JIS 5005 is defined as the weight-percentage of
stones passing through sieves as follows:
______________________________________ 60 mm: 100%; 50 mm: 95 to
100%; 25 mm: 35 to 70%; 15 mm: 10 to 30%; and 5 mm: 0 to 5%. ______________________________________
It is difficult for an anvil-type impact crusher to produce stones
of a large grain size and to produce stones having good shape, while
it is difficult for a dead stock-type impact crusher to produce
stones of a small grain size.
A further problem is that tips are worn by accelerated stones.
A rotor is provided with pairs of tips mounted on the wings thereof.
Stones of a large size, the diameter of which is larger than 40
mm, generate more chipping-type wear than stones of a small size.
Material harder to chip is preferably applied for tips which are
used in a crusher for crushing stones of a large size. Stones of
small size, the diameter of which is smaller than 40 mm, generate
more erosive-type wear than stones of a large size. A higher degree
of erosive wear-resistant material is preferably applied for tips
which are used in a crusher for crushing stones to a small size.
As such, there is an inconsistency in the tips used in impact crushers
for large sized stone-crushing and those used for small sized stone-crushing.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a vertical shaft-type
impact crusher for crushing stones of various sizes which overcomes
the inconsistency of stones of a large size generating more chipping-type
wear than those of a small size, thereby material hard to chip being
preferably applied for tips which are used in a crusher for crushing
stones of a large size, while stones of a small size generate more
erosive-type wear than stones of a large size, thereby a higher
degree of erosive-type wear-resistant material being preferably
applied for tips which are used in a crusher for crushing stones
of a small size.
Another object of the present invention is to provide a vertical
shaft-type impact crusher for crushing stones of various sizes which
has a high production efficiency.
Still another object of the present invention is to provide an
operation method for a vertical shaft-type impact crusher for crushing
stones of various sizes in which the life of the tips is extended.
Still another object of the present invention is to provide an
operation method for a vertical shaft-type impact crusher for crushing
stones of various sizes in which a plurality of the crushers are
simultaneously operated, whereby the production efficiency is high.
Still another object of the present invention is to provide an
operation method for a vertical shaft-type impact crusher for crushing
stones of various sizes in which a plurality of crushers are simultaneously
operated, whereby the life of tips is extended.
In one aspect of the invention, the vertical shaft-type impact
crushers have a rotor mounted on a casing body, the rotor being
reversely rotatable for giving thrown stones centrifugal force,
and anvils for crushing stones discharged from the rotor. The anvils
are mounted in the circumferential area around the rotor. Dead stock
spaces for crushed stones to be accumulated therein are located
in the circumferential area around the rotor. The anvils are located
between the respective intervals given in the peripheral direction
around the rotor.
In the above aspect, the vertical shaft-type impact crushers have
a dead stock-forming plate for forming dead stock spaces thereabove.
The dead stock-forming plate surrounds the rotor and has a bore
in which the rotor is located.
Also vertical shaft-type impact crusher of the invention has an
adjustable means for adjusting the distance between the respective
anvils and the rotor, the adjustable means being located between
the respective anvils and the inner surface of the casing body.
In the above aspect of the vertical shaft-type impact crusher,
the bore is circular, and furthermore, has a ring for adjusting
the volume of the dead stock space. The ring is replaceably mounted
on the peripheral edge of the circular bore.
In another aspect of the invention, the vertical shaft type-impact
crusher has a rotor mounted on the casing body. The rotor is reversely
rotatable for giving thrown stones centrifugal force. The vertical
shaft-type impact crusher has anvils mounted in the circumferential
region around the rotor. The rotor includes multiple pairs of tips,
the respective pairs of tips being located symmetrically with respect
to the angularly oriented radial axes disposed at equal angular
intervals. The axes extend from, and are perpendicular in the radial
direction to, the rotational axis of the rotor. The respective tips
of the respective pairs, which point forward in the rotational direction
with respect to the respective radial axes, are made of hard material
in comparison with material that follows. The respective tips of
the respective pairs, which point backward in the rotational direction
with respect to the respective axes, are made of softer material
in comparison with the above hard material.
In another aspect of the invention, in an operation method for
the vertical shaft-type impact crusher, hard material is employed
for the forward-pointing tips mounted in the respective dead stock
spaces in which respective dead stocks are formed on the rotor rotated
in the forward rotational direction, and softer material is employed
for the front tips mounted in the respective dead stock spaces where
respective dead stocks are formed on the rotor rotated in the reverse
rotational direction. The rotation of the rotor in the forward direction,
or in the reverse direction, is operated in response to the grain
size of the raw stones supplied to the crusher.
In the above aspect of the invention, in the operation method for
the vertical shaft-type impact crusher, the rotor is rotated in
the forward direction in cases in which the grain size of raw stone
is large and the rotor is rotated in the reverse direction in cases
in which the grain size of raw stone is small.
In the above aspect of the invention, in the operation method for
the vertical shaft-type impact crusher, the rotation of the rotor
in the forward direction, or in the reverse direction, is operated
in response to the degree of wear of the hard tips in comparison
with that of the softer tips.
In the above aspect of the invention, in the operation method for
the vertical shaft-type impact crusher when used in multiple numbers,
the rotor of a first crusher into which stones of a large grain
size are supplied is rotated in the forward direction, and the rotor
of a second crusher into which stones of a small grain size are
thrown down is rotated in the reverse direction.
In another aspect of the invention, the vertical shaft-type impact
crusher has a rotor mounted on the casing body and which is reversely
rotatable for giving thrown stones centrifugal force. The crushers
have dead stock spaces for crushed stones to be accumulated therein.
The dead stock spaces are located in the circumferential area around
the rotor. The anvils for crushing stones discharged from the rotor
are mounted in the circumferential area around the rotor. The respective
anvils are located between the respective dead stock spaces with
the intervals occurring in the peripheral direction around the rotor,
while the rotor includes multiple pairs of tips, the respective
pairs of tips being located symmetrically with respect to the angularly
oriented axes disposed at equal angular intervals, the axes extending
from the rotational axis line of the rotor in the radial direction.
Respective tips of the pairs which point forward in the rotational
direction with respect to the respective axes are made of hard material
in comparison with material that follows. Respective tips of the
pairs which point backward in the rotational direction with respect
to the respective axes are made of softer material in comparison
with the above hard material.
In the vertical shaft-type impact crushers of the present invention,
stones are crushed by collision with not only anvils but also dead
stocks. The dead stocks are formed with the respective angles of
rest. Some stones are smoothed by the dead stocks, while the other
stones are crushed into stones of a small grain size.
Stones of a large size collide with less hard tips, while stones
of a small size collide with harder tips. The wear of the harder
tips brought about by the collision with stones of a large size
is less because of the rotation in the forward rotational direction.
The wear of the softer tips brought about by the collision with
stones of a small size is less because of the rotation in the reverse
direction.
The other aspects and operations of the present invention are explained
in detail through embodiments of the present invention as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a first embodiment of a vertical shaft
type impact crusher in accordance with the present invention.
FIG. 2 is a cross-sectional view of the crusher of FIG. 1.
FIG. 3 is a top view of a dead stock space of another embodiment.
FIG. 4 is a horizontal cross-sectional view of FIG. 1.
FIG. 5 is a vertical cross-sectional view of the rotor of the crusher
of FIG. 1.
DETAILED DESCRIPTION OF EMBODIMENTS
Referring now to the figures, an embodiment of a vertical shaft-type
impact crusher constructed in accordance with the present invention
is described in the following. FIGS. 1 and 2 illustrate a vertical
shaft-type impact crusher. A casing 1 includes a casing body 1a
and a covering lid 1b. Covering lid 1b is rotatably mounted on the
upper portion of the casing body 1a by means of a mounting means
(not shown).
Covering lid 1b is opened and closed relative to the casing body
1a by means of a lever 5 which pivots about a pivot axis and is
forced upwardly and downwardly by a hydraulic cylinder 4. Covering
lid 1b has an inlet opening 2. Two guide chutes 7 and 8 are located
at the respective lower positions of the inlet opening 2 affixed
to the suspended portion of the casing body 1a. Lower guide chute
8 is attached to a multiple number of vertically suspended, circumferentially
spaced ribs 8a. Vertically suspended ribs 8a are provided as a portion
of the casing body 1a.
A rotor 10 is located under the guide chute 8. Rotor 10 is mounted
on a top surface of the vertical rotating shaft 11. Vertical rotating
shaft 11 is rotatably supported in the axle-housing 15 through bearings
13 and 14. Axle-housing 15 is mounted on the casing body 1a through
brackets 16. A pulley 17 is attached to the lower portion of the
vertical rotating shaft 11. Pulley 17 is connected to a reversible
motor (not shown) through a belt (not shown). Vertical rotating
shaft 11 is rotated in alternate directions in response to the operation
of the motor.
Rotor 10 includes a rotor body 21 a distributing cone-like body
22 three circumferentially spaced wings 23 23 23 and three pairs
of liners disposed intermediate the respective wings. Distributing
cone-like body 22 is mounted on the upper side of the central portion
of the rotor body 21. The respective three wings 23 23 23 are
adjustably positionable in three angular intervals of 120 degrees
therebetween. Pairs of liners are placed between the respective
wings in the respective 120 degree angular intervals. Casing 1 is
generally square in the sectional view.
As shown in FIG. 1 four protecting liners 40 are fixedly mounted
on the respective inner side surfaces of the respective walls forming
the casing 1. A dead stock forming plate 30 is horizontally disposed
in the casing body 1a. Dead stock forming plate 30 is designed as
a square plate of which the peripheral edge portion is affixed against
the inner surface of the casing body 1a.
As shown in FIG. 1 dead stock forming plate 30 has a circular
opening 31 the diameter of which is designed to be larger than
that of the rotor 10. Circular opening 31 and rotor 10 have a common
central axis-line. Four anvils 32a, 32b, 32c, 32d are located upwardly
apart from the dead stock forming plate 30. Respective anvils 32a,
32b, 32c, 32d have respective anvil members 33 affixed to the respective
central portions of the inner surfaces of the casing body 1a.
Each anvil member is made of an erosive wear-resistant material,
e.g., manganese steel. The locations of the anvils 32 create four
dead stock spaces 34a, 34b, 34c, 34d formed therebetween. Respective
dead stock spaces 34a, 34b, 34c, 34d are respectively provided as
four corner portions partly forming the inner space of the casing
1.
Each horizontal distance between each anvil and the rotor 10 is
adjustable as follows. Spacers 35 are replaceably inserted between
the respective surfaces of the casing body 1a and the respective
anvil members. The number of the spacers 35 enables the above distance
in the horizontal direction to be adjustable.
The volume of the dead stock spaces 34a, 34b, 34c, 34d is also
adjustable as follows. As shown in FIGS. 1 and 2 diameter-adjusting
ring 36 is located at the circumferential edge of the circular opening
31. Adjusting ring 36 is circumferentially divided into a multiple
of segments 37. Each segment is replaceably affixed to the dead
stock forming plate 30 by means of a bolt 38.
A flange 41 is formed the inner circumferential edge portion of
the respective segments 37. Many kinds of segment groups, the radii
of which are different from one another, can be prepared. The replacement
of the segment group allows the above volumes of the dead stock
spaces 34 to be altered. A multiple number of single body rings
may be used for altering the ring diameter.
Another embodiment of a diameter-adjusting ring is illustrated
in FIG. 3. Each segment 37 has an elongated hole 37a extending in
the radial direction. The mounting position of the segment 37 relative
to the dead stock-forming plate 30 is aligned in the radial direction.
Each segment is secured to the dead stock-forming plate 30 by means
of a bolt (not shown in FIG. 3) passing through the elongated hole
37a. In this case, a space is formed between adjacent segments 37
37. Such spaces do not cause any problems because they become filled
with crushed rocks.
FIGS. 4 and 5 illustrate the detailed structure of rotor 10. A
liner 50 to protect the rotor body 21 is fittedly mounted on the
outer periphery of the rotor body 21. Liner 50 is bolted to the
rotor body. A flat plane 52 is formed as the top surface of the
distributing cone-like body 22 in the center of the upper side thereof.
The outer periphery of the distributing cone-like body 22 is formed
as a tapered surface 53 around the rotor axis.
A circular recess 54 is formed on the lower side of the distributing
cone-like body 22. Recess 54 engages with a circular step portion
55 formed on the top surface of the rotor body 21 thereby locating
the body cone-like 22 at the proper position. The distributing cone-like
body 22 has a bore 56 in the center thereof allowing an engaging
portion of a suspending means (not shown) to be engaged therewith
during assembly and disassembly.
Each wing 23 includes a support 57. Supports 57 are fixedly mounted
on the rotor body 21 and are disposed on the outer peripheral zone
around the distributing cone-like body 22. Supports 57 are provided
as three bodies disposed in the three angular orientations equal
on 120 degree circumferential spacing.
Each support 57 includes a radially extending portion 58 a circumferentially
extending portion 59 and a plate portion 60. Radially extending
portion 58 extends in the radial direction on the rotor body 21
while the circumferentially extending portion 59 generally extends
oppositely in circumferential back-and-forth directions on the rotor
body 21 from the outer portion of the radially extending portion
58.
By means of the plate portion 60 the radially extending portion
58 is integrally secured to the circumferentially extending portion
59. Discharge passage liners 24 are located between each pair of
supports 57 57 in the above described respective angular intervals.
A projection 61 is provided on the lower side of the discharge passage
liner 24. Projection 61 is fitted into a recess 62 provided on the
upper side of the rotor body 21 thereby effecting the positioning
of the discharge passage liner 24. When the discharge passage liner
24 is disposed on the rotor body 21 with the distributing cone-like
body 22 placed at the proper position, a notch portion 63 is engaged
with the discharge passage liner 24. This causes the distributing
cone-like body 22 to press the discharge passage liner 24 against
the rotor body 21.
A first wall liner 64 is fixedly mounted on the outside of each
support 57. Studbolts 65 as integral screw members are provided
for the first wall liner 64. Nuts are fittedly inserted into the
studbolts 65 of the first wall liner 64 by which the first wall
liner 64 is secured to the circumferentially extending portion 59
of the support 57. On the circumferentially extending portions 59
of the respective supports 57 are mounted second wall liners 66
third wall liner 67 and outer tip plates 68. Studbolts 71 as integral
screw members are provided with the second wall liner 66. The third
wall liner 67 is secured at the intermediate position between the
second wall liner 66 and the circumferentially extending portion
59 by means of the studbolts 71 and nuts (not shown) fitted on the
studbolts 71.
As shown in FIG. 4 super-hardness tips or non-super-hardness tips
72 are mounted on the base body 69 of the outer tip plates 68. A
non-super-hardness tip 72 is made of hard steel or hard alloy, e.g.,
Cr-steel or Ni-Cr-steel, that is more easily worn but hard to chip
because of its pliability. The expression, "to be hard to chip",
means, in strength of material, that chipping wear is comparably
less. On the other hand, the expression, "super-hardness",
means that the super-hardness of steel or super-hardness of the
alloy is more wear resistant but is easier to chip.
The expression, "to be easy to chip", means, in strength
of material, that chipping wear is comparably more. Examples of
super-hard alloys are known as sintered alloys, included in WC-Co
series, WC-TiC-Co series, WC-TiC-TaC (NbC)-Co series, TaC-Ni series,
Cr-Ni series that correspond in hardness to diamond and are made
by means of a sintering method in which Fe-composition combined
with soft carbide is molded under pressure and sintered after molding.
It is apparent from the above definition that not only may alloy
be applied for super-hardness tips, but fine ceramics, as well.
The two portions 59 extending oppositely in the circumferential
back-and-forth direction are the same in structure. Inner tip plates
73 are disposed on the inner peripheral portion of the supports
57. These plates are U-shaped to receive the radially extending
portion 58 of the wing support 57. Each inner tip plate 73 includes
an inside tip and right and left side tips. These tips are made
of material of the same kind as the above material for tips 72
that is super-hardness alloy or non-super-hardness alloy, as described
above.
In the state where inner tip plate 73 is mounted on the support
57 the lower portion of the inside tip plate 73 is engaged with
the chipping portion of the distributing cone-like body 22. Support
57 is covered by means of a top covering plate 77. A step portion
78 for positioning is formed on the lower side of the top covering
plate 77. Step portion 78 is fitted into a recess formed on the
plate portion 60 of the support 57 thereby the top covering plate
77 is positioned at the proper engaged position.
A downwardly bent portion 79 is formed as an inner side edge of
the top covering plate 77. Inner tip plate 73 is secured to and
between the downwardly bent portion 79 and the distributing cone-like
body 22. Top covering plate 77 is affixed to the plate portion 60
of the support 57 and the base body 69 of the outer tip plates 68
by means of a bolt 80 and other bolts (not shown) at four positions.
FIG. 4 illustrates three centerlines L, M, N which are in different
angular positions. Line L is different from line M by 120 degrees.
Line M is different from Line N by 120 degrees. Line N is different
from Line L by 120 degrees. Respective centerlines L, M and N are
aligned with the centerlines of the respective radially extending
portions 58 58 58 of the supports and are perpendicular to the
rotational axis K of the rotor 10 meeting at one point on the axis
K.
The three rotor portions 10LM, 10MN and 10NL of the rotor 10 between
one selected centerline and the two other adjacent centerlines and
between the two other centerlines are substantially congruent to
each other. Wing 23L has symmetry with respect to the centerline
L. Wing 23M has symmetry with respect to the centerline M. Wing
23 N has symmetry with respect to the centerline N. As an example,
the base bodies 69 are given as a set of two base bodies 69L1 and
69L2 that are circumferentially symmetrical with respect to the
centerline L. The other base bodies 69 are given as a set of two
base bodies 69M1 and 69M2 that are circumferentially symmetrical
with respect to the centerline M. The still other base bodies 69
are given as a set of two base bodies 69N1 and 69N2 that are circumferentially
symmetrical with respect to the centerline N.
As such, all parts included in the rotor 10 are symmetrically located
with respect to each centerline L, M, or N. Such symmetry is needed
for high speed rotation of the rotor 10. The tips 72 are fixedly
mounted on the two respective base bodies 69L1 and 69L2 as a set
of two tips 72L1 and 72L2 that are symmetrical to each other with
respect to the centerline L. Each of the other tips 72 are fixedly
mounted on the respective other base bodies 69M1 and 69M2 as pairs
of tips 72M1 and 72M2 that are symmetrical to each other with respect
to the centerline M. The still other tips 72 are fixedly mounted
on the respective two base bodies 69N1 and 69N2 as a pair of tips
72N1 and 72N2 that are symmetrical to each other with respect to
the centerline N.
According to such a location of the tips, tip 72L1 and tip 72M2
are located in the rotor portion 10LM, tip 72M1 and tip 72N2 are
located in the rotor portion 10MN and tip 72N1 and tip 72L2 are
located in the rotor portion 10 NL. One group of tips 72L1 72M1
and 72N1 that have the respective phases identical with one another
in the rotational direction, are made of super-hardness material
as defined above. The other group of tips 72L2 72M2 and 72N2 that
have the respective phases identical with one another in the rotational
direction, are made of ordinary material that is non-super-hardness
material as defined above. One group of tips 72L1 72M1 72N1 and
the other group of tips 72L2 72M2 72N2 are all replaceable. It
is not necessary to apply a super-hardness material for the inner
tip plates 73.
Dead spaces 91L, 91M and 91N occur within the respective wings
23L, 23M and 23N on the both sides in the circumferential direction.
One group of dead spaces 91L1 91M1 and 91N1 are in the same phase
in the rotational direction. The other group of dead spaces 91L2
91M2 and 91N2 are in the same phase in the rotational direction.
The respective phases of the dead spaces 91L1 and dead spaces 91L2
are different from each other.
Dead space 91L1 and dead space 91L2 are symmetrical with respect
to the centerline L. Dead space 91M1 and dead space 91M2 are symmetrical
with respect to the centerline M. Dead space 91N1 and dead space
91N2 are symmetrical with respect to the centerline N. Each dead
space is located between one of the wings 23 and one of the discharge
passage liners 24.
(Operation of the Embodiment)
Rotor 10 is driven at a high speed by a driving motor (not shown).
Raw rocks are supplied onto the rotor through the inlet opening
2 and through the guide chutes 7 and 8. The supplied raw rocks are
distributed by the distributing cone-like body 22 along the discharge
passages formed between the respective two adjacent wings. Such
distributed raw rocks are accelerated with a given centrifugal force.
This causes the rocks to be discharged from the peripheral end of
the rotor.
Such discharged raw stones are crushed into stones with smaller
diameters by collision with one of the anvils 32a, 32b, 32c, 32d.
Some crushed stones are accumulated on the dead stock forming plate
30 of the dead stock spaces 34a, 34b, 34c, 34d. At the beginning
of the operation, accumulated crushed stones do not perfectly form
a dead stock. In a short time, a sufficient amount of stones are
accumulated on the dead stock forming plate 30 to form a perfect
dead stock. As shown in FIG. 2 four dead stocks 42 42 42 42
are formed with respective angles of repose. As a result, discharged
raw stones are crushed by collision with such formed dead stocks.
Other dead stocks are also formed with respect to the rotor 10
by stones that are prevented from discharging by the supports 57
and the circumferentially extending portion 59. Such dead stocks
have the respectively specified angles of repose under operation
of centrifugal force and gravitational force. Collision of raw stones
with anvil 32 which has a high degree of hardness and is made of
manganese steel causes discharged stones to be crushed into relatively
small radii, while collision of raw stones with dead stock 42 which
has a low degree of hardness and is formed of accumulated stones
causes discharged stones to be crushed into relatively large radii.
It is not accurate to say that the collision of a stone with a dead
stock is to be expressed as "crush". A stone colliding
with a dead stock is reduced little in radius, but is merely made
smooth because of surface wear.
Changing the horizontal distance between each anvil 32 and the
rotor 10 not only makes stones different in material or size to
be of the same grain size, but also makes stones equivalent in material
or size to be of different grain size. A decrease in the number
of the spacers 35 enables the achievement of crushed stones of a
small grain size, while an increase in the number the spacers 35
enables the achievement of crushed stones of a large grain size.
Otherwise, alteration of the inner radius of the adjusting ring
36 enables the change of the grain size of crushed stones.
Raw stones, that are accelerated and rolled on the surface of the
dead stocks accumulated on the dead stock forming plate 30 in the
dead stock spaces 34a, 34b, 34c, 34d, collide with tips 72. Tips
72 wear less easily but are easier to chip when the thrown raw stones
are of large grain size. On the other hand, tips 72 are harder to
chip but easier to wear when the thrown raw stones are of small
grain size.
Controlling the operation of a crusher according to the present
invention enables the production efficiency to increase. Super-hardness
tips 72L1 72M1 72N1 are applied as tips mounted in the dead stock
spaces 91L1 91M1 91N1 where dead stocks are formed with respect
to the rotor when it is rotating in one direction (i.e., the clockwise
direction), while non-superhardness tips 72L2 72M2 72N2 are applied
as tips mounted in the dead stock spaces 91L2 91M2 91N2 where
dead stocks are formed with respect to the rotor when it is rotating
in the reverse direction (i.e., the anti-clockwise direction). Operation
control includes means to rotate the rotor 10 in the clockwise direction
or to rotate the rotor 10 in the anti-clockwise direction in correspondence
to the grain size or grain size distribution of the raw stones supplied
to the crusher.
For the large size of stones being produced, that is, raw stones
being of large size, the rotor is rotated in the clockwise direction
as seen in FIG. 4. Most stones collide with the non-super-hardness
tips 72L2 72M2 72N2 that are less worn because of a lower collision
frequency and hard to chip because of its physical properties.
For the small size of stones being produced, that is, raw stones
being of small size, the rotor is rotated in the anti-clockwise
direction. Most stones collide with the non-super-hardness tips
72L1 72M1 72N1 that are hard to chip because of their small moments
and of less wear because of their physical properties, despite a
higher collision frequency.
Such an operation method may be conducted on a regular basis but,
alternatively, may be performed intermittently on an irregular basis
in combination with the regular operation. When large sized stones
are produced, the rotor is rotated in the clockwise direction and
when small sized stones are produced, the rotor is rotated in the
anti-clockwise direction. In consideration of the degree of abrasion
to be experienced by the non-super-hardness tips 72L1 72M1 72N1
or by the non-super-hardness tips 72L2 72M2 72N2 regular rotation
or irregular rotation may be operated. Such a combination of regular
operation with irregular operation results in an extension in the
common tip life.
A single crusher is not always used. A number of crushers according
to the present invention may be simultaneously or synchronously
operated. It is normal that a number of crushers are operated in
relation to each other. Simultaneous operation enables processes
to be synchronous in which stones of a large grain size are in multi-processes
crashed into stones of a small grain size. Rotors are rotated in
the respective rotational directions in the respective processes:
a first step crasher being rotated in the clockwise direction; a
second step crasher being rotated regularly in one direction or
irregularly in alternate directions; a third step crusher being
rotated in the anti-clockwise direction. Such a group-control operation
results in an extension of the tip life. |