Abstrict A method and apparatus for adjusting the gap width between a rotatable
crusher cone and a crusher housing includes determining a reference
position of the crusher cone relative to the crusher housing, storing
a first quantity representative of the reference position, rotating
the crusher cone, moving the crusher cone to the reference position,
moving the crusher cone from the reference position toward the crusher
housing until a limit is reached and measuring the distance of the
crusher cone from the reference position, storing a second quantity
representative of the distance, repeating the preceding three steps
a plurality of times while separately storing each of the second
quantities, obtaining a new reference position based on each of
the second quantities, and determining an operating position of
the cone crusher based on the new reference position. The apparatus
includes a control device, a memory, a position detecting device
for detecting the position of the crusher cone, and an apparatus
for detecting whether the crusher cone is moving.
Claims I claim:
1. A method for adjusting the gap width between a rotatable crusher
cone and a crusher housing, comprising the steps of:
(a) determining a reference position of the crusher cone relative
to the crusher housing;
(b) storing a first quantity representative of said reference position;
(c) moving said crusher cone to said reference position;
(d) moving said crusher cone from said reference position toward
said crusher housing until a limit position is reached, stopping
the movement of said crusher cone toward said crusher housing when
the limit position is reached, and measuring the distance between
said reference position and said limit position;
(e) storing a second quantity representative of said distance;
(f) repeating steps (c)-(e) a plurality of times while separately
storing each of the second quantities;
(g) obtaining a new reference position by analyzing each of said
second quantities in conjunction with each other;
(h) determining an operating position of said cone crusher based
on said new reference position;
(i) moving said crusher cone to said new operating position; and
(j) performing steps (c)-(i) while continuously rotating said crusher
cone.
2. A method as claimed in claim 1 wherein in step (d) said limit
position is reached upon contact of said crusher cone with said
crusher housing, said contact being detected by measuring movement
of said crusher cone.
3. A method as claimed in claim 1 wherein in step (d) said limit
position is reached upon contact of said crusher cone with said
crusher housing, said contact being detected buy measuring pressure
of a fluid which causes movement of said crusher cone.
4. A method as claimed in claim 1 further comrising in step (g)
comparing each of said second quantities with each other to determine
which one represents the furthest movement of said crusher cone
in the direction of said crusher housing, and selecting that quantity
as representing said new reference position.
5. A method as claimed in claim 1 further comprising in step (f),
when repeating step (c), first moving said crusher cone to an opening
position which is different from said reference position.
6. A method as claimed in claim 5 further comprising in step (g)
after repeating step (c) in step (f), setting said opening position
to be at a predetermined fixed distance from said new reference
position.
7. A method as claimed in claim 1 further comprising the step
of (k) automatically repeating steps (c)-(i) at preselectable timed
intervals.
8. A method as claimed in claim 1 further comprising in step (d),
before the first movement of said crusher cone toward said crusher
housing, providing a time delay starting from interruption of a
supply of material which is to be crushed.
9. A method as claimed in claim 1 wherein in step (d) further
comprising first supplying a granular material of known coarseness
of the gap between said crusher cone and said crusher housing, whereby
said limit position is reached before direct contact occurs between
said crusher cone and said crusher housing.
10. A method for adjusting the gap width between a rotatable crusher
cone and a crusher housing, comprising the steps of:
(a) determining a reference position of the crusher cone relative
to the crusher housing;
(b) storing a first quantity representative of said reference position;
(c) moving said crusher cone to said reference position;
(d) moving said crusher cone from said reference position toward
said crusher housing until a limit position is reached, stopping
the movement of said crusher cone toward said crusher housing when
the limit position is reached, and measuring the distance between
said reference position and said limit position;
(e) storing a second quantity representative of said distance;
(f) repeating steps (c)-(e) a plurality of times while separately
storing each of the second quantities;
(g) obtaining an average of the values of said second quantities,
and storing a new reference position which is representative of
said average;
(h) determining an operating position of said cone crusher based
on said new reference position;
(i) moving said crusher cone to said new operating position; and
(j) performing steps (c)-(i) while continuously rotating said crusher
cone.
Description The invention relates to a method for the adjustment of the gap
width of a cone-type crusher or the like, having a crusher cone
rotating tumblingly and being height-adjustable in respect to the
crusher housing. The crusher cone, by approaching the crusher housing,
can be brought into a reference position and an operating position.
The travel of the crusher cone is determined corresponding to a
set gap width by which the crusher cone should be distant from the
reference position to the operating position. The approach of the
crusher cone to the crusher housing is detected by means of a movement
detection measurement and the respective crusher cone position is
determined by means of a distance measurement.
The gap width, i.e. the width of the crusher discharge gap between
the stationary crusher housing and the crusher cone located approximately
concentrical on the inside of said crusher housing is of decisive
importance for crushing effect and crushing performance of a cone-type
crusher or a crusher of similar construction: if the crusher gap
width is small, the material to be crushed is crushed more finely
than if the crusher gap is larger.
Because of the wear of the crusher cone and crusher housing occurring
during operation, the width of the crusher gap changes, with the
result that the crushed product slowly shows increasing coarseness.
Account of this unwanted effect must be taken by resetting the gap
width at least periodically to a set value.
The axial inclination of the crusher cone results in its having
a smallest and a largest distance, with corresponding transition
zones, from the stationary crusher housing; the point forming the
smallest distance is referred to as the effective width of the crusher
gap.
In a known method, described in British Pat. No. 1080085 the
gap width is set, with the crusher cone at rest, by means of a movement
detection measurement in the form of a pressure measurement and
by a distance measurement such that the crusher cone is first brought
to the crusher housing until it touches it and, based on the reference
position thus determined, a movement of the crusher cone away from
the crusher housing corresponding to a predetermined gap width is
initiated. Attainment the reference position is determined via a
pressure sensor installed in the circuit of the hydraulic shifting
drive of the crusher cone; the amount of travel performed during
the opening movement into the operational position is determined
by means of the measurement of the volume of liquid displaced by
the opening movement. The width of the crusher gap and the amount
of wear can be determined by an inductive distance measurement;
this is accomplished by means of a measuring piston which penetrates
into a coil to a larger or smaller degree. The known method can
also be operated automatically according to a preset program, either
after every stopping of the crusher cone or less often.
A method for the electrical determination and adjustment of the
gap width of a cone-type crusher is already known, for example,
from German Laid-Open Application DE-OS 20 51 398.
SUMMARY OF THE INVENTION
It is an object of the invention to describe a method and the components
necessary for its operation by which the accuracy of setting the
width of the crusher gap is improved. The method should especially
be such that, if possible, different types of wear of the crusher
cone and/or crusher housing can be taken into consideration when
adjusting the gap.
The object is attained by performing successively several approach
cycles with the crusher cone rotating, each cycle consisting of
the approach of the crusher cone to the crusher housing and the
subsequent opening movement away from the crusher housing, and to
use the approach values gained with every approach cycle for the
formation of a reference value fixing the reference position. On
the basis of this reference value, that position of the crusher
cone is determined which it should have to maintain the operating
position in a desired gap width.
The approach operations conducted in the framework of the approach
cycles can either be such that, if need be, the rotating crusher
cone comes to rest momentarily against the crusher housing or is
kept momentarily (especially by means of a layer of test material)
at a short, reproducible distance from the crusher housing. In accordance
with the invention the determination of the reference position can
therefore be based on attaining a momentary touching position (when
reaching the "zero gap width") or an almost touching position
(when reaching the "almost zero gap width") between the
crusher cone and crusher housing.
By "movement detection measurement" in the sense of the
method according to the invention is meant a measuring or sensing
method or the like which shows whether the crusher cone has finished
its respective approach operation within the framework of the predetermined
number of approach cycles, i.e. that it has stopped (if there is
no malfunction) against the crusher housing or close to the crusher
housing.
Collection of the measurements important for the method and control
of the associated component (drives, valves) is appropriately performed
via a control unit into which a computer having sufficient memory
capacity has been integrated.
The end of the approach of the crusher cone directly against the
crusher housing or approximately towards it via a layer of test
material can be measured--especially inductively--via a speed measurement
and/or via a pressure measurement--for example in the pressure system
of a hydraulic shifting drive of the crusher cone. The respective
position of the crusher cone in respect to the stationary crusher
housing can be determined, for example, by the previously noted
known distance measuring methods.
The method is preferably structured such that a mean value is formed
from associated approach values, which constitutes the reference
value; the mean value can especially be calculated from the arithmetic
or the quadratic mean of the associated approach values.
The method of the invention, however, can also be practiced in
such a way that from the associated approach values a certain approach
value is selected as a reference value, namely the one showing the
greatest displacement of the crusher cone in the direction of the
crusher housing determined during the approach cycles.
In an advantageous embodiment of the method the crusher cone, at
least after the end of each approach cycle or if desired before
the first approach cycle, is first brought into a predetermined
opening position which deviates from the reference position. The
advantage of this procedure can be seen in the fact that each approach
cycle, i.e. the approach of the crusher cone to the crusher housing
and the subsequent return to the predetermined opening position,
takes place under similar conditions.
Additionally, the distance between the opening position and the
reference position can be kept constant. This can, for example,
be done by adapting the location of the opening position to the
change noticed after the reference position has been determined.
If the changing values for the location of the opening position
or the reference position are stored and shown in the form of a
curve, the development of wear in the associated time period (to
which the respective positions are to be associated) can be read
from it and a reference point for future wear development can also
be obtained.
The method can be advantageously developed in this context such
that the stored opening position values or reference position values
are compared with a predetermined limiting value. Reaching this
limiting value serves as a signal, for example optical or accoustical,
that the worn part of the cone-type crusher (crusher cone, crusher
housing) must be replaced.
In a number of applications it is sufficient to trigger the checking
and adjustment of the gap width by hand at a suitable time after
the cone-type crusher is empty. The adjustment procedure is performed
such that first the supply of material to be crushed to the cone-type
crusher is interrupted, before the approach cycles for the determination
of the desired reference position automatically start, with a sufficient
time delay. Preferably the approach cycles and the subsequent movement
of the crusher cone into the operating position are automatically
started in predetermined time intervals, the first approach cycle
starting with a time delay for the interruption of the supply of
the material to be crushed.
The already mentioned storage of the reference positions or the
opening positions adapted to them is advantageous to the degree
that false measurements (for example generated by foreign materials)
can be detected by comparison with the stored position values and
can be suppressed as not usable.
If the approach operations always start from the same known opening
position, it is possible to check by means of repeated time of travel
measurements whether the crusher cone has at least traveled a known
distance up to the time of stopping.
The determination of reference positions can also be accomplished
such that the crusher cone is only brought into the vicinity of
the crusher housing in the course of the approach cycles. Each of
these approach procedures end as soon as the rotating crusher cone
rests against the crusher housing over a layer of test material
of a known coarseness. The layer cooperating in the formation of
the reference position can be made by introducing, at least during
the approach procedures, test material in sufficient quantity into
the crusher discharge gap, instead of the material to be crushed.
The method variant under discussion has the advantage that the determination
of the reference position takes place without contact between the
rotating crusher cone and the stationary crusher housing.
BRIEF DESCRIPTION OF THE DRAWING
The invention is described in detail below with reference to the
FIGURE of the drawing, in which a cone-type crusher with components
used in a method of operation being shown schematically.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The housing of a cone-type crusher 1 in connection with which
the method of the invention is used, includes an upper housing part
2a with a supply inlet 2b and a discharge opening 2c, an adjoining
central housing part 2d only partially shown, and a lower housing
part 2e having an upwardly oriented axial bearing 2f.
A crusher cone 3 is disposed pivotably and adjustable in height
inside the housing, its replaceable cone casing 3a and a crusher
housing 4 in the form of a truncated cone and replaceably fixed
to the upper housing part 2a forming a cone discharge gap 5. The
crusher cone 3 is fixedly fastened by means of an attachment ring
6 to a shaft 7 which, in turn, is secured via a pivot bearing 8
which is disposed on the upper housing part 2a. The shaft is supported
by a radial bearing of a rotating drive housing 9 on the central
housing part 2d and, at its downwardly directed front face 7a, on
a height-adjustable piston 10a which is driven by a stationary hydraulic
cylinder 10. The drive housing 9 is provided with a gear ring and
rests on the axial bearing 2f. The drive housing 9 is connected,
via a drive element in the form of a toothed belt 11 with a pinion
12a of a three-phase A.C. motor 12.
The shaft 7 is eccentrically supported within the drive housing
9 because of the eccentric support of the shaft 7 in the drive housing
9 the crusher cone 3 has a tumbling motion inside the crusher housing
4 when the three-phase A.C. motor 12 is operated, the narrowest
spot between the parts 3a and 4 being referred to as a cone discharge
gap 5 the cone discharge gap 5 rotating during operation with respect
to the crusher housing 4.
A conveyor element 13 is placed ahead of the supply inlet 2b, including
a hopper 13a, a spiral conveyor 13c driven by a conveyor motor 13b
and a conveyor chute 13d terminating in the supply inlet 2b. The
conveyor motor 13b is connected via a control line 14 with a control
element 15 with which is integrated a computer 15a having a timer
control unit 15b and sufficient storage capacity for the timed monitoring
and control of the method steps.
The motive power supply system for the hydraulic cylinder 10 includes
a motor-driven hydraulic pump 16 two remote-controlled valves 17
and 18 which are, respectively, installed in the pressure line 19
and the return line 20 of the hydraulic cylinder 10 and an oil
reservoir 21 in which terminate the lines 19 and 20 as well as the
return line 17a of the valve 17. A pressure sensor 22 is switched
upstream of the valve 17 in the direction of the hydraulic cylinder
10 and is connected via a signal line 23 with the control element
15. The components 16 to 18 are respectively connected with the
control element 15 via signal lines 24 25 and 26.
The respective position of the crusher cone 3 in relation to its
stationary surroundings is measured by means of a distance measuring
unit consisting of a measuring element 27a fastened on the shaft
7 and a stationary distance measuring sensor 27b which is connected
via a measuring line 28 to the control element 15.
In order to be able to draw conclusions, if required, in regard
to the operational state of the cone-type crusher 1 from the power
consumption of the three-phase A.C. motor 12 a current-measuring
device 29 is associated with the said drive, the measured values
of which can be entered via a signal line 30 into the control element
15 and processed there.
Certain data stored in the computer 15a can, if required, be displayed
by means of a view screen 31 connected to the control element 15.
In order to manually start the checking and adjustment of the crusher
discharge gap, if required, the control element has a manual switch
32.
The method of the invention proceeds as follows:
By actuation of the manual switch 32 the conveyor motor 13b is
first stopped via the control element 15 and the control line 14
thereby interrupting the supply of the material to be crushed into
the area of the inlet opening 2b of the cone-type crusher 1 while
the crusher cone 3 continues to tumblingly rotate and to crush the
remaining material received which is to be crushed. The measured
value corresponding to the working position of the crusher cone
3 which is picked up by the distance measuring sensor 27b has already
been stored in the memory 15a during the preceding adjustment of
the crusher cone to the present working position.
The crusher cone 3 is lowered into an opening position, which is
predetermined by the memory 15a after a predetermined selectable
time delay via a delay member, not shown, forming a part of the
control element 15. The predetermined selectable time delay occurs
after the actuation of the manual switch 32 and actuates the piston
10a by closing of the valve 17 and opening of the valve 18. The
time delay is selected so that with sufficient assurance the cone-type
crusher 1 does not contain in the area of components 3 and 4 any
material to be crushed, i.e. it is empty.
After reaching the opening position the crusher cone 3 is momentarily
brought into contact with the crusher housing 4 by an appropriate
switching of the hydraulic pump 16 as well as of the valves 17 and
18 in several subsequent approach cycles and then returned to the
predetermined opening position. The approach values corresponding
to the contact on the crusher housing 4 are collected by the distance
measuring sensor 27b and are stored in the computer 15a. After the
last approach cycle, which ends with the return of the crusher cone
into the said opening position, the arithmetic mean value is formed
in the computer from the approach values sensed, which represents
the reference value fixing the reference position of the crusher
cone and which is also stored.
By a comparion of the reference value and of a value corresponding
to the operational position which is also stored in the computer
a distance value is determined corresponding to a predetermined
gap width by which the crusher cone 3 must be distant from the reference
position. The adjustment movement required of the shaft 10 is in
turn caused by an appropriate adjustment in the height of the piston
10a as monitored by the distance measuring sensor 27b the piston
10a being locked in the new adjusted position assumed.
The new distance measuring value is stored which corresponds to
the working position is also stored.
The approach of the crusher cone 3 to the crusher housing 4 when
valve 18 is closed is sensed via the pressure sensor 22 which inputs
the pressure increase in the hydraulic cylinder 10 via the measuring
line 23 to the control element 15. On the basis of this and by the
appropriate operation of the valves 17 and 18 the control element
15 causes the return of the crusher cone 3 to the opening position
already mentioned.
The timer control unit 15b can be used to assign the stored values
for the reference position and/or the working position to the associated
time intervals. In this way it is possible to display, for example,
the stored values for the working position of the crusher cone 3
applied over time, on the view screen 31 and to obtain from this
an indication of the wear so far present on the components 3a and
4.
However, the timer control unit 15b, together with the distance
measuring elements 27a, 27b, can also be used to monitor the approach
operations during the approach cycles. To the extent that there
are no false measurements, the crusher cone 3 can only touch the
crusher housing 4 when the approach operation has ended, i.e. when
the distance measurement value recorded by the distance measuring
sensor 27b no longer changes in respect to the time set by the timer
unit 15b. By cooperation of the components 27a, 27b and 15b, false
measurements can be prevented if, at the same time, by comparison
with already stored approach values, a check is made whether the
crusher cone has traveled a minimum distance in the direction towards
the crusher housing 4.
Other than in the method just described, the checking and adjustment
of the gap width can also be automatically started and completed
with the participation of the timer unit 15b. For example, the timer
unit can be set such that it independently starts the method of
the invention once a day.
The method of the invention also can be designed in such a way
that in addition to or in place of the pressure measurement by means
of the pressure sensor 23 an inductive measuring operation is used,
such as is, for example, known from the German Laid-Open application
mentioned above. By use of a measuring piston which, depending on
the movement of the crusher cone 3 penetrates more or less deeply
into a stationary coil, not only a change in distance travelled
but also movement can be detected; for instance, it can be determined
whether the crusher cone 3 has stopped after touching the crusher
housing 4.
However, the movement of the crusher cone 3 into a predetermined
working position can also be accomplished on the basis of a reference
position where the tumblingly rotating cone crusher 3 only almost
touches the crusher housing 4.
In order to obtain reproducible approach values for the determination
of such a reference position with sufficient accuracy, testing material
of known coarseness is first supplied via the conveyor unit 13 to
the input opening 2b after emptying the cone-type crusher 1 at least
during the approach cycles. The test material forms a layer in the
gap area on top of which the crusher cone 3 is only indirectly supported
against the crusher housing 4. Although this method entails additional
effort, it has the advantage that a reference position of the crusher
cone 3 can be determined via reference values without it having
to touch the crusher housing 4 during the chronological approach
cycles.
To the extent that the location of the opening position is respectively
adapted to the changing reference position and the corresponding
values are stored, a result can be obtained, by comparison of the
stored values with a limiting value, for the opening position as
to the amount of wear present or whether replacement of the cooperating
wear components 3a and 4 is required.
The main advantage of the method of the invention consists in determining
the reference value, based on which a predetermined working position
of the crusher cone is controlled by several approach cycles representing
sensing operations, and while the crusher cone 3 is rotating. Since
several reference values are chronologically determined, an uneven
wear of the two cooperating wear components is also included in
the reference value and thus influences the adjustment of the width
of the crusher discharge gap 5. |