JPH04247272A - Method for controlling vibrating screen - Google Patents

Abstract

PURPOSE:To eliminate clogging of a vibrating screen consisting of an inclined frame over which a screen mesh is laid and transferring a material on the mesh by its vibration by driving the screw mesh vibrating part with a sufficiently larger force than in the normal operation for each specified cycle. CONSTITUTION:A couple of vibrating motors 8a and 8b are energized, an unbalancing weight is synchronously rotated, and a trough 2 is linearly vibrated in the direction (a) by the linear vibrating force due to the resultant force. Each screen mesh vibrating part 12 is energized, and a screen mesh 3 is vertically vibrated. A material to be screened is supplied from an inlet 6 under these conditions, transferred to the right in a specified bed thickness and separated by the screen mesh 3 into oversize and undersize. In this case, the vibrating part 12 is driven by a larger force than in the normal operation for each cycle for a specified time. Consequently, an impulsive force is applied to the screen mesh, and clogging is eliminated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for preventing clogging of a sieve screen in a vibrating sieve device.

0002

[Prior Art and its Problems] There are various types of vibrating sieve devices that sieve the material while transferring it on the sieve net by vibrating a trough on which a sieve net is stretched. However, the particle size of this sieve material is small, and depending on the material, it can easily become clogged.In contrast, in the past, for example, the sieve was placed below the sieve net and housed in the frame. Some devices prevent clogging by applying impact from below due to the bouncing motion of the ball, but the structure is complicated and the device assembly is troublesome.

[0003] Also, by attaching the tip of a driving rod to the sieve screen and vibrating the drive rod in a direction approximately perpendicular to the surface of the sieve screen, the sieve screen is not only vibrated for transport but also prevented from clogging. There are devices designed to improve the sieving efficiency, but even in such devices, it is difficult to install a large number of drive rods over the entire sieve net, and similar to the impact caused by the balls mentioned above, some parts of the sieve net are affected. Although clogging can be prevented, it is difficult to prevent clogging throughout the screen.

0004

[Problems to be Solved by the Invention] The present invention has been made in view of the above problems, and can prevent clogging of material throughout the sieve net with a simple structure, and can maintain the initial high sieving efficiency. The purpose of the present invention is to provide a method for controlling a vibrating sieve device.

[0005]

[Means for Solving the Problems] The above object is to incline and/or vibrate the frame on which the sieve net is stretched, so that the material is transferred on the sieve net, and the sieve net In a method of controlling a vibrating sieve device, the vibrating sieve device includes at least one sieve screen vibration drive unit that extends substantially perpendicularly to the sieve screen and applies vibration force to a rod-shaped member attached to the sieve screen. This is achieved by a method of controlling a vibrating sieve device, which is characterized in that the driving force of the vibrating sieve device is controlled to be sufficiently larger than that during normal operation for a predetermined time at each predetermined period.

[0006]

[Operation] When a large driving force is generated, the sieve screen is vibrated greatly by the rod-shaped member, thereby causing material that is clogged or about to become clogged to be removed from the sieve screen. Therefore, efficient sieving can be performed over a long period of time.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vibrating sieve device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a vibrating sieve device according to an embodiment of the present invention, designated as a whole by 1, in which a sieve screen 3 is stretched in a trough 2. In FIG. 1, a sieve material discharge port 4 and a sieve material discharge port 5 are formed at the right end of the trough 2, and a sieve material supply port 6 is formed at the left end. A vibration drive unit mounting plate 7 is integrally formed on the bottom wall of the trough 2, and a pair of known vibration motors 8a and 8b are fixed to the rear end of this plate.

[0009] The trough 2 has a pair of front, rear, left and right supports 9a,
Anti-vibration springs 11, 11, 11, 1 on 9b, 10a, 10b
1. Further, on the bottom wall of the trough 2, a sieve mesh vibration drive unit 12 according to the present invention is installed as shown in FIG. 3 in this embodiment.
As shown in the figure, five pieces (their positions are indicated by the bolts 34 at the tips) are attached. An electromagnetic vibration feeder 14 is disposed directly above a sieve material supply port 6 formed at the left end of the trough 2, and sieve material is supplied from a hopper 13 to this feeder 14. Also hopper 13
The electromagnetic vibration feeder 14 is placed on a pedestal 15.

Next, the sieve mesh vibration drive unit 12 according to the present invention
The details will be explained below. In this embodiment, these are arranged at five locations as shown in FIG. 3, but since they all have the same configuration, one sieve mesh vibration drive unit 1 shown in FIG.
2 will be explained. This includes a cup-shaped casing 21 as shown in FIG. 4, and its upper end is attached to a pair of angle members 23a and 23b fixed to the bottom wall 2a of the trough 2 by, for example, welding, as shown in FIG. bolt 19
, 19. As shown in FIG. 4, a stationary electromagnet 28 is fixed to the bottom wall of the casing 21 with a coil 29 wound around it, and a movable core 27 is supported by a pair of springs 30 with a gap therebetween. There is. The lower end of a rod 26 is fixed to the center of this movable core 27, and as shown in FIG. An increased diameter part 32 as a mounting part is integrally formed, and an umbrella member 31 made of cup-shaped metal is fixed so as to surround this part.
It is arranged so as to cover the portion protruding from a and the portion under the sieve falling toward the diameter-increasing portion 32 integrally formed at the upper end thereof. Further, a sieve screen mounting member 33 is fixed to the increased diameter portion 32 by bolts 34 above the umbrella member 31 and facing the sieve screen 3 with the sieve screen 3 interposed therebetween. That is, the increased diameter portion 32 is formed with a screw hole (not shown), and the bolt 34 is inserted into the bolt insertion hole formed in the mounting member 33, and the threaded portion of the bolt 34 is inserted into the screw hole formed in the increased diameter portion 32. By tightening the screw into the hole, the rod 26
The distal end portion is configured to be clamped and fixed to the sieve net 3. Further, a cylindrical protrusion 25 is integrally formed on the peripheral edge of the opening 24 formed in the bottom wall 2a of the trough 2, and a rod 26 passes through this.
A cylindrical covering member 35 made of rubber is elastically fixed to the increased diameter portion and the protrusion 25 at its upper and lower ends between the upper end portion and the increased diameter portion 32 .

As described above, the rod 26 is completely covered with the under-sieve material. Next, the structure for tensioning and attaching the sieve net 3 to the trough 2 will be explained with particular reference to FIG. 5.

Mounting members 42a and 42b bent in a V-shape are attached to both side edges of the sieve screen 3, and a pair of holding members 90a and 90b extend along the longitudinal direction of the trough 2. The upper end portions 41a, 41b are elastically pressed against the inner wall of the trough 2. As shown in FIG. 5, the mounting member 42a
, 42b are engaged with the lower end of the holding member 90, and the bolts 4 are inserted into holes formed in the vertical plate portions of the holding members 90a, 90b.
The bolts 43a, 43b are inserted through openings in the side wall 2b of the trough 2, and the bolts 43a, 43b are inserted through openings in the side wall 2b of the trough 2.
3b to the spring 44a, spring receiving member 45a of 44b.
, 45b and nuts 46a, 46b.
By screwing and tightening, the sieve net 3 is installed in the trough 2 under tension with a tension corresponding to the compressive force of the springs 44a and 44b.

As described above, the vibrating sieve device according to the embodiment of the present invention is mechanically constructed, but according to the present invention, as shown in FIG. A vibrator drive circuit 100 is connected thereto, and a setting device 101 for adjusting each output of the drive circuit 100, which will be described later, is also connected thereto. The vibrator drive circuit 100 generates a current whose voltage is constant but whose frequency f periodically changes as shown in FIG. 7, the current applied to each coil 29 changes with a period of time T, and initially generates an alternating current with a frequency f0, but this changes over a predetermined time ΔT, for example, every 0.02 seconds. The current increases stepwise by Δf, for example, every 0.2 Hz, and this is transmitted to the coil 29 of each sieve mesh vibration drive unit 12.
In this way, by increasing Δf for each ΔT,
After time (T-T0), f1 Hz increases from f0 Hz. f0 Hz is, for example, 100Hz, and f1
Hz is 40Hz. Therefore, the frequency increased by 40 Hz during the time (T-T0). This maximum frequency 1
When the frequency of 40 Hz continues for a predetermined time ΔT, the voltage becomes almost zero or zero, and the frequency f also becomes zero. This time is the time T0, and the period T includes this rest period T0, and the circuit is configured such that such periodic frequency changes are repeated every period T time.

Furthermore, according to this embodiment, as shown in FIG.
The frequency is changed every cycle, but the voltages except for the rest period T0 of this cycle T are all constant as shown in FIG. 8, and this is shown as F' in FIG. That is, the magnitude of the voltage changes in a pulse-like manner with a constant time width. According to this embodiment, a pulse P of a higher voltage with a longer time width than the pulse F' is generated at a larger period, for example, every 20 hours (this is referred to as M in FIG. 8).
is generated from the vibrator drive circuit 100.

[0015] The above T, ΔT, Δf, T0, f
0, f1, etc. can be adjusted using the setting device 101.

The vibrating sieve device according to the embodiment of the present invention is constructed as described above, and its operation will be explained next.

In FIG. 1, a pair of vibration electric motors 8a and 8b
When the power is applied to the
It vibrates in a straight line in the direction shown by . It is also assumed that each sieve mesh vibration drive unit 12 is also energized. In FIG. 1, sieve material is supplied from a hopper 13 to a sieve material supply port 6 of a trough 2 by an electromagnetic vibration feeder 14. Since the trough 2 is vibrating linearly in the direction of the arrow a, the sieving material supplied from the supply port 6 forms a certain layer thickness and is transferred to the right in FIG. 1 by the vibration. During this process, the sieve net 3 separates the sieve into an upper sieve and a lower sieve, and according to this embodiment, five sieve net vibration drive units 12 are fixed to the sieve net, as shown in FIG. Since the coil 29 is now energized with the above-mentioned alternating current, an alternating attractive force is generated between the coil 29 and the movable core 27, which causes the rod 26 to vibrate in the vertical direction. Therefore, the sieve screen 3 fixed at its tip is vibrated. The frequency f of the alternating current applied to the coil of this sieve mesh vibration drive unit 12 is assumed to be sufficiently high, and the sieve mesh 3 vibrates at a high frequency in response to this, thereby applying an impact force. The sieve material can be efficiently and sharply sieved into the top and bottom of the sieve without clogging. Therefore, in FIG. 1, the sieve material carried to the right side of the trough 2 is discharged to the outside from the sieve material outlet 4, and the sieve material is discharged to the outside from the sieve material outlet 5.

As described above, the material is sieved on the sieve net 3, and the material under the sieve falls onto the bottom wall 2a of the trough 2. It is then transferred over this bottom wall by linear vibration, and during this process, the bottom wall 2a of the trough is formed with a cylindrical protrusion 25 at the periphery of the opening, as shown clearly in FIG. Therefore, it is transported around this area and does not enter into this cylindrical protrusion 25. That is, the casing 21 of the sieve mesh vibration drive unit 12
It does not invade inside. Furthermore, according to this embodiment, since the covering member 35 made of cylindrical rubber is fixed between the increased diameter part 32 and the protruding part 25 at the upper end of the rod 26, the material under the sieve is completely protected from the sieve mesh vibration. Casing 21 of drive unit 12
Prevented from entering. Furthermore, since the umbrella member 31 is attached to cover the increased diameter part 32, the material under the sieve avoids the protrusion 25 and falls onto the bottom wall 2a of the trough 2. This not only prevents water from entering the casing 21, but also prolongs the life of the rubber covering member 35 (because the material under the sieve is not exposed to direct heat). Also, the sieve net 3 and the bottom wall 2a of the trough 2 undergo relative vibration,
Since the cylindrical member 31 is made of rubber, this deflection is absorbed and does not cause any adverse effects on the vibration of the rod 26.

The vibrating sieve device according to the embodiment of the present invention operates as described above.Next, the operation for replacing the sieve screen 3 will be explained.

When replacing the sieve net with a new one, the sieve net 3 can be easily removed from all the sieve net drive parts 12 by loosening the bolts 34 from above. On top of this, nuts 46a and 46 are screwed onto bolts 43a and 43b that are inserted through holding members 90a and 90b that are engaged with attachment parts 42a and 42b at both edges of the sieve screen 3.
The sieve net 3 can be easily removed by loosening and removing b. Next, since mounting parts similar to the mounting parts 42a and 42b are provided on both edges of the new sieve screen,
The lower ends of the holding members 90a and 90b are engaged with this as shown in FIG.
, 44b and tightening the nuts 46a, 46b, a new sieve screen can be installed in the trough 2 under tension at a predetermined tension. Next, by screwing and tightening the bolts 34 into the screw holes of the increased diameter portions 32 with the attachment members 33 interposed, the tips of the rods 26 of each sieve net drive portion 12 can be fixed to the new sieve net 3. According to this embodiment, the sieve mesh vibration drive unit 12
Since the casing 21 is fixed to the bottom wall 2a of the trough by bolts 19 via a pair of mounting members 23a and 23b as shown in FIG. 6, the sieve screen can be replaced while the casing 21 is attached. , the exchange action of the sieve mesh is much simpler than before.

Next, the operation of the sieve mesh vibration drive unit 12 according to the embodiment of the present invention will be explained in detail. A rod 26 of the sieve net vibration drive section 12 is connected to the sieve net 3. A current as shown in FIGS. 7 and 8 is applied to each sieve mesh vibration drive unit 1.
As a result, the frequency of the current flowing through the coil changes at a period T as shown in FIG. 7 during a period other than the pulse P shown in FIG. 8. As a result, at the attachment part of each sieve screen 3 (see Fig. 3),
Because the tension of the sieve screen 3 at the mounting position of each rod 26 (indicated by 34 in FIG. 3) and the weight of the material being transferred on it are different, the resonance frequency is different for each part. , this is shown in Figure 7 from f0 to f1
Due to the stepwise frequency change increasing by f1, the vibration of the drive rod 26 is configured such that the vibration of the sieve screen 3 passes through the resonant frequency while increasing by f1. The net part vibrates with a large amplitude. Therefore, the sieve material passing through this can be efficiently sieved.

As described above, the resonant frequencies of each part can be effectively utilized over almost the entire area of the sieve net 3 shown in FIG. 3, and the sieving efficiency as a whole can be greatly improved.

Furthermore, according to this embodiment, each parameter can be changed by the setting device 101, but this is because when the sieve net 3 is replaced, its tension changes, and the tension of the sieve net 3 supplied thereon changes. Since the resonant frequency of each part changes depending on the specific gravity of the material and its characteristics, by adjusting the parameters of this setting device 101, it is possible to adjust the resonant frequency of each part effectively over almost the entire area of the sieve net 3. Can be done.

Furthermore, according to this embodiment, as shown in FIG. 8, since pulses P are generated at a large voltage and with a large time width every long period M, the coil 29 of each sieve mesh vibration driving section 12
When the sieve is energized, it shakes with a large width, and as a result, the sieve screen 3 is likely to be clogged, especially when fine powder material is being sieved as a sieve material, because the sieve screen 3 is subjected to an impact force due to the large oscillation width. Since the sieving efficiency is as follows, clogging will not occur in a short period of time, but clogging may occur in a long period of time, so clogging is caused by pulses P every cycle M, or clogging does not occur. The sieve material that is being used as the sieve material is separated from the sieve net 3 as an upper sieve and a lower sieve by impact. Therefore, the main sieve net 3
can guarantee high sieving efficiency over a long period of time.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the embodiments described above, a pair of vibrating electric motors were used to vibrate the trough, but the vibration driving section is not limited to this, and an electromagnetic driving section may also be used. Alternatively, the frame body may be tilted downward and the material transfer drive unit may be omitted.

Further, in the above embodiment, five sieve mesh vibration drive units are provided, but of course, it may be provided at one location, or a larger number of sieve vibration drive units may be provided.

Furthermore, in the above embodiments, during normal driving, the frequency f0 is increased stepwise for a predetermined time by Δf every ΔT time, but instead of such a driving method, a fixed frequency, for example, a constant f0 is used. The sieve screen may be vibrated at a frequency of , and a driving force larger than usual may be applied as a pulse P at predetermined time intervals, that is, at every M. This also makes it possible to significantly reduce clogging of the sieve mesh compared to the conventional method.

Further, in some cases, as shown in FIG. 9, for example, when the sieve net vibration drive section 12 is connected to the sieve net 3 at five locations as in the embodiment, each of the sieve net vibration drive sections 12 may be On the other hand, vibrator drive circuits 100a, 100b, 100c, 100d and 10 configured as described above
Each dimension ( f0,
Δf, ΔT, etc.) may be adjusted.

[0030]Of course, among these, alternating current of a constant frequency may be applied to a certain sieve mesh vibration drive unit 12 as in the conventional case without changing the frequency as shown in FIG. Furthermore, as shown in FIG. 8, a pulse P for preventing clogging was generated every period M, and the height of this pulse was also varied for each sieve mesh vibration drive unit 12 to find the one that caused the most clogging. For easy positions, the height of this pulse P may be increased. Alternatively, this pulse P may not be generated.

Furthermore, the structure of the sieve screen vibration driving section 12 may be changed as shown in FIG. Note that portions corresponding to those in FIG. 4 are designated by the same reference numerals, and description thereof will be omitted.

That is, in FIG. 10, a pair of pillars P are integrally planted in the casing 21, and urethane rubber G is adhered to the upper ends of the pillars P. The gap g between these urethane rubber G and the movable core 27 is the fixed electromagnet 2.
8 and the pole surface of the movable core 27, that is, the distance is smaller than the air gap Q. Therefore, during normal driving, the movable core 27 does not collide with the fixed electromagnet 28, but when a large driving force is applied every predetermined time M, the attractive force to the movable core 27 becomes large, and therefore, with a large amplitude. However, before it collides with the fixed electromagnet 28, it collides with the urethane rubber G on the support column P, and as a result, in addition to a large vibration amplitude, the rod 26 is subjected to an impact force due to the urethane rubber G through the movable core 27. is added. As a result, the sieve screen 3 attached to the upper end surface of the rod 26 is not only vibrated to a greater extent than usual, but also receives an impact force, that is, a large acceleration α, which causes the sieve screen 3 attached to the top end of the rod 26 to A large shock wave is applied not only to the vicinity of the sieve net 3 but also to the entire sieve net 3, and as a result, the sieve material that has clogged the eyes of the sieve net 3, or the sieve material that is about to become clogged, is reliably removed. It is separated from the mesh of the sieve mesh 3 as the sieve top or sieve bottom. Therefore, the effects of the present invention can be more reliably obtained by receiving an impact force (large gravitational acceleration) even if the swing width is simply the same.

Also, according to FIG. 9, each setting device 101a, 10
1b, 101c, 101d, and 101e can adjust the driving force of the sieve screen vibration drive unit 12 at each mounting position relative to the sieve screen 3, but the time and height of the pulse P can be changed using the setting devices 101a to 101e, respectively. You may also do so. Further, the period at which the pulse P is applied may be changed depending on each position.

[0034]

[Effects of the Invention] As described above, according to the control method of the vibrating sieving device of the present invention, clogging of material can be prevented over the entire sieve net with a simple structure, and the initial high sieving efficiency can be maintained. can be done.

[Brief explanation of the drawing]

FIG. 1 is a side view of a vibrating sieve holder according to an embodiment of the invention.

FIG. 2 is a front view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is an enlarged sectional view of a main part of the sieve mesh vibration drive unit in the same embodiment.

FIG. 5 is an enlarged sectional view taken along line [5]-[5] in FIG. 3;

FIG. 6 is a sectional view taken along line [6]-[6] in FIG. 5;

FIG. 7 is a graph showing frequency waves of the current applied to the sieve mesh vibration drive unit in the same example.

FIG. 8 is a graph showing temporal changes in the voltage applied to the sieve mesh vibration drive section.

FIG. 9 is a block diagram showing the arrangement of a sieve mesh vibration drive unit and a drive circuit therefor in a vibrating sieve device according to a modified example.

FIG. 10 is a sectional view showing a modification of the sieve mesh vibration drive unit.

[Explanation of symbols]

3 Sieve net 12 Sieve net vibration drive unit 26 Rod 29 Coil 100 Vibrator drive circuit

Claims (2)

[Claims] Claim 1: The material is transferred on the sieve net by tilting and/or vibrating a frame on which a sieve net is stretched, and the frame body extends substantially perpendicularly to the sieve net; In a method for controlling a vibrating sieve device comprising at least one sieve screen vibration drive section that applies vibration force to a rod-shaped member attached to a sieve screen, the driving force of the sieve screen vibration drive section is controlled at predetermined intervals. 1. A method of controlling a vibrating sieve device, comprising controlling the vibrating sieve device to a sufficiently larger driving force than during normal operation for a predetermined period of time. 2. The method of controlling a vibrating sieve device according to claim 1, wherein the predetermined period and the predetermined time are adjustable.