JPS5848219B2 - Device that prevents metal contact between grinding members and measures and controls spacing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the spacing between grinding members in a disk crusher type grinding device, such as a refining device.

The spacing between the grinding elements must be maintained at a predetermined value, in order to obtain a grinding product of the required quality and to avoid damage to the grinding elements or the entire grinding device due to contact of metal materials with each other. It is made extremely small to prevent this.

It is known to utilize electrical circuitry to indicate the actual spacing between electrically conductive grinding members in order to control the spacing mentioned above.

According to the invention, one pole is connected to at least one part of one of the grinding members which is electrically insulated from the other part of the grinding member, and the other pole is connected to the other part of the grinding member. By providing an electrical circuit with an additional power source, the length of the current path through the circuit is increased.

The electrical current in the circuit is forced through the other grinding member and the electrically conductive medium present in the grinding gap by means of an insulating layer separating the two parts mentioned above from each other.

By lengthening the current path in the electrical circuit, it is possible to improve the accuracy of indicating changes in the spacing between the grinding elements and thus the width of the grinding gap.

Thus, according to the present invention, it is possible to obtain a measuring device that produces an easily visible runout in response to changes in electrical resistance caused by changes in the width of the grinding gap.

This makes it possible to activate a regulating device for automatically readjusting the width of the grinding gap, whereby the quantity or quality of the material to be ground can be varied.

The automatic readjustment device provided by the invention makes it possible to completely eliminate the risk of metal contact between the grinding elements during operation as quickly as possible in response to any changes in the spacing of the grinding elements.

The invention provides that at least one of the grinding members can be rotated via a rotating shaft and a power device such as a servo motor to apply axial pressure on the material to be ground passing into the gap between the two electrically conductive grinding members. and electrically insulating the crushing fan plate of at least one of the crushing members and the at least one electrically conductive member connected thereto from other parts of the crushing device for crushing the material to be configured. The present invention relates to a device for measuring and controlling the distance between grinding members in a grinding device by means of an electric circuit.

For example, the spacing between grinding discs in grinding equipment, such as refiners, often needs to be adjusted in response to changes in volume, concentration, and load to obtain the desired high quality of the ground product.

However, it is not possible to constantly control the operator to make the above-mentioned adjustments quickly enough.

As a result, the directly opposing grinding disks or the grinding fan plates attached thereto come into metal contact with the underframe and the shaft by compression, tension, temperature changes, or elongation caused by these.

Such metal-to-metal contact causes wear of the grinding disc or sector plate, and in severe cases leads to complete destruction.

An object of the present invention is to provide a device capable of preventing the metal contact described above.

Another object of the invention is to provide a highly sensitive device that can quickly measure the distance between the two grinding members so that the distance between the two grinding members can be adjusted in a simple manner.

Still another object of the present invention is to provide a device for automatically adjusting the spacing between grinding members.

The device according to the invention is characterized in that the electrical circuit comprises a power source, one pole of which is connected to an insulated part of one of the grinding elements and/or a part connected to this part, and the other pole of which is connected to at least one of the parts of the same grinding element. the other, optionally insulated, part or at least one part connected to this part;
said parts having different poles connected to these parts or to both parts and thereby being overbridged directly via the other grinding element or via the electrically conductive medium present in the grinding gap and the other grinding element. Alternatively, the circuit is closed by a part connected to these parts or an electrically insulating layer between these parts, so that the distance between the crushing members is determined by an electric current.

According to the invention, by the configuration described above, the measuring distance, i.e. the path of the current in the electrically conductive medium present in the gap between the grinding disks, can be increased by twice the measuring distance of known devices of the above-mentioned type. Make it.

As a result, the sensitivity of the circuit to changes in the width of the gap between the grinding disks is greatly increased.

Twice the measuring distance is usually problematic due to the small gap between the grinding discs and because of the relatively thin insulation layer between said parts of the grinding member, the current of the circuit is directed away from the insulating part of the grinding member. and flows from this to the other part.

Furthermore, when using the device according to the invention, both poles of the power supply can be connected to the stationary comminution element, so that the problematic connection via rear end contacts or similar devices can be completely eliminated.

The invention will now be described with reference to the illustrated preferred embodiments.

In the drawing, the device according to the invention is shown in combination with a comminution device constituted by a refining device 10 for processing fibrous or shavings-like materials.

However, the invention can be applied to many similar applications.

As shown in the drawings, a shaft 14 is mounted on the underframe 12 of the device 10 and supported by bearings 16 and 18.

The bearings 16, 18 are suitably configured to permit axial movement of the shaft 14 supported by the bearings.

The detailed structure of such a bearing is known as described in US Pat. No. 3,212,721.

A rotor 20 is mounted on the shaft 14 and a grinding disk 22 is provided on this rotor.

The rotor 20 and the grinding disk 22 are rotatable together with the shaft 14.

A fixed grinding disk 24 is fastened to the horizontally divided casing 26 above the shaft 14 by bolted joints 34 .

The material to be crushed is passed through the central passage 28 in the casing 26.
The separated grinding disks 22, 24 are supplied to the apparatus 10 through
sent outward into the interstices.

A discharge opening 30 is provided at the bottom of the casing 26 for removing the ground product.

In the illustrated example, the stationary grinding disk 24, which is secured to the casing 26 by a bolted joint, is electrically isolated from the casing 26.

This insulation can be provided, for example, by an insulating plate 32 inserted between the back side of the stationary grinding disk 26 and the casing 26.

The insulating plate 32 can be made of a suitable insulating material, and the material can be selected arbitrarily.

For example, a plastic gasket of an appropriate thickness may be suitably used for the purposes of the present invention.

An insulating material 36, which in the illustrated example is a plastic material, is inserted between the bolt 34 used to fasten the stationary grinding disk 24 to the casing 26 and the casing 26.

An insulating material 36 is provided below the bolt head 38 and also extends in the radial direction.

This arrangement electrically isolates the entire stationary grinding disk 24 from all other parts of the grinding device 10.

However, this is not necessary to realize the basic structure of the invention.

According to the invention, it is necessary to electrically insulate only a portion of one of the grinding members from the rest of the grinding device.

In the illustrated example, this part is constituted by a known crushing fan-shaped plate 40 having a plurality of ridges, and an insulating plate 32 along the short radial side and the side facing the axis 14. An electrically insulating layer 42 of the same type is provided.

A grinding disk 24 of the type described above is usually constructed with 12 grinding sectors.

In order to completely achieve the required insulation of the sector plate 40, an insulating plate member occupying only the space between the sector plate 40 and the casing 26 may suffice in place of the insulating plate 32 shown in the drawings.

A fluid servo motor 44 is mounted around the shaft 14 of the device 10.

The cylinder 46 of this servo motor 44 can be formed integrally with the bearing casing 18, and the piston 48 can be connected to the shaft 1.
Install concentrically leaving some play around 4.

Piston 48 is formed with a central flange 50 that is axially movable within cylinder 46 .

A pilot valve 52 is fixed to the cylinder 46 of the servo motor 44.

A piston 54 in this pilot valve 52 is formed with a central flange 56 and two side flanges 58,60.

The pilot valve 52 further includes a central chamber 62 and two side chambers 6.
4 and 66, and the inner diameter of the adjacent valve 52 is adapted to the outer diameter of the flanges 56, 58, 60.

The axial dimension of the flange 56 is made extremely slightly shorter, such as 1/100 to 5/100, compared to the longitudinal dimension of the chamber 62.

Similarly, the axial dimension of flanges 58,60 is very short compared to each of the associated chambers 64 and 66.

In the central position, all flanges 56 , 58 . 6
0 as a straight line in front of the respective associated chambers 62, 64, 66, respectively.

A pipe 68 connects the center chamber 62 of the pilot valve 52 to the oil tank 70.
and a pump (not shown) is installed inside the oil tank 70.

A return pipe 72 connected to pipe 68 is connected to oil tank 70 via spring loaded valve 14 .

Chamber 6 reduced in diameter to approximately the same diameter as the flange diameter
2 and 64 from the space 76 of the pilot valve 52 to the pipe 7
8 extends into a chamber 80 on one side of the flange 50 of the servo motor 44.

A small diameter space 84 located on the other side of the central chamber 62 of the pilot valve 52 is connected by a tube 82 to a chamber 86 located on the other side of the flange 50 .

The side chambers 64,66 are also connected to the oil tank 70 by return pipes 88 and 90, respectively.

A screw 94 is attached to an arm 92 fixed to the servo motor piston 48.
is screwed in so that the thread is coaxial with the piston 54 of the pilot valve 52 and acts on the end of the piston that projects outwardly from the valve casing.

The spring pressure of a spring 96 is applied to the outer end of the piston 54 to force the valve piston 54 toward the screw 94.

The position of the screw 94 can be adjusted by a reversible electric motor 98 and the driving force can be directly transmitted to the screw 94 by the motor shaft, or the motor shaft can be formed integrally with the screw 94.

Oil at a constant pressure is supplied from the oil tank 70 to the central chamber 62 of the pilot valve 52 via a pipe 68.

The piston 54 of the pilot valve 52 is constantly pressed against the screw 94 by the action of the spring, causing the piston 54 to follow the axial movement of the screw 94.

Due to the accumulation of material to be crushed in the grinding gap between the fixed grinding disks 22 and 24, the grinding disks 22. As the pressure between 24 increases, the rotating grinding disk moves against the servo motor piston 48.
Since the screw 94 has been adjusted to a fixed position within the arm 92 connected to the piston 48, the screw 94 is pushed and moved to the left.

The piston 54 of the pilot valve follows the movement of the screw 94.

As a result, as described above, the space 84 of the pilot valve 52
and increases the oil pressure in the servo motor 86.

Correspondingly, the oil pressure in the servo motor chamber 80 is reduced.

In order to maintain the spacing between the grinding discs 22, 24, the pressure on the servo motor piston 54 is increased.

Usually, this interval is 0.2 to 0. 5 mm.

In the opposite situation, i.e. when the grinding discs 22,24 approach each other due to the lack of material supply, the servomotor piston 48 and the screw 94 follow this movement, thereby forcing the pilot valve 52 to the right. Moving.

In this way, the pilot valve 52 and the servo motor chamber 80
increases the pressure in space 76 and decreases the pressure in space 84 and servo motor chamber 86.

Flange 56.58.60 of pilot valve piston 54
Since the difference in axial dimension between the chambers 62, 64, 66 surrounding them is very small, only small displacements of the piston 54 are sufficient to change the grinding pressure.

By changing the relative position of the screw 94 with respect to the arm 92, the initially adjusted spacing between the grinding discs 22.24 can be increased or decreased.

This is necessary to eliminate metal contact between the discs 22, 24 due to tensile elongation of the frame and/or shaft.

By adding the device according to the invention to the known grinding device, two grinding disks 22. The spacing between 24 can be determined very accurately.

A measuring device constructed for this purpose is shown in FIG.

In FIG. 2, arrows 100 indicate connections to other components that are controlled by the measurement results of the measuring device.

The measuring device according to the invention includes a DC power source 104, a grinding disk 22
.

The two different branches 108, 110 of the circuit 102 are directly connected to mutually electrically isolated parts of the stationary grinding disk 24.

With such an arrangement, an indication of the spacing between the grinding discs 22, 24 can be received directly on a measuring device, preferably constituted by an ammeter connected to the measuring electrical circuit 102, which The reason is that water is usually present in the material to be crushed (not shown) located between the grinding discs.

Water is a poor electrical conductor, so that very minute changes in spacing can be accurately read on meter 106.

Measuring device 1 for controlling electric motor 98 that drives screw 94
Motor 98 is connected to meter 106 by conductor 112 so that 0.06 readings or indications can be used.

With this configuration, the crushing disk 22 can
．． The interval between 24 can be adjusted automatically.

In addition to indicating the spacing between the grinding discs 22.24, the device according to the invention makes it possible to obtain an automatic control device that prevents the grinding elements from stopping or completely breaking due to metal contact between the grinding discs 22.24. can.

In both the wet grinding and dry grinding described above, when direct metal contact occurs between the grinding discs, the circuit 10 described above
2 closes immediately.

In such a case, the electric motor 98 is controlled by the meter 106 or other suitable device, such as an electrical circuit breaker or similar device connected to the circuit, to immediately separate the grinding disks 22,24 from each other and to separate the grinding disks 22,24 from each other. continuous metal contact, thus preventing the grinding disk or the entire grinding device from being destroyed.

The present invention prevents contact between grinding disks in a refining device,
As mentioned above, the device according to the invention determines the spacing between two grinding members that are rotatable relative to each other, or prevents metal contact between such grinding members. It can also be applied to other types of grinding equipment that require

Of course, the electrically insulated part of the grinding device can be constructed with more than one grinding sector.

Modifications to the apparatus described above with respect to the drawings may be made within the scope of the invention.

For this reason, the part of one grinding member which is electrically insulated from all other parts of the grinding device can be constructed with a separate electrical conductor which projects through the grinding member and onto the grinding surface.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a disk-type refining device equipped with the device according to the present invention, FIG. 2 is a perspective view showing the device of the present invention together with a part of the refining device shown in FIG. 1, and FIG. 3 is a crushing member. FIG. 10... Refining device, 12... Underframe, 1
4... Shaft, 16, 18... Bearing casing, 20... Rotating body, 22, 24...
・Crushing disk, 26...Casing, 28...
...Center passage, 30...Discharge port, 32...
...Insulating plate, 34...Bolt, 36...
...Insulator, 40...Sector plate, 42...
・Electrical insulation layer, 44... Servo motor, 46.
...Cylinder, 48 ...Piston, 50
... Center flange, 52 ... Pilot valve, 54 ... Piston, 56.58.60.
...flange, 62, 64, 66 ... chamber, 74 ... valve, 92 ... arm, 94 ...
...Screw, 96...Spring, 102...
...Measuring circuit, 108... Measuring instrument.

Claims (1)

Claims: 1. A device for measuring and controlling the distance between two electrically conductive grinding members 22, 24 in a grinding device 10 for grinding materials by means of an electric circuit 102, the device comprising: .24 to apply an axial pressure on the material to be crushed passing through the gap between the crushing members 22;
is rotatable via a rotating shaft 14 and a power device such as a servo motor 98, and the crushing sector plate 40 of at least one crushing member 24 and the at least one electrically conductive member connected thereto are connected to the crushing device. 10, in which one pole of a power source 104 provided in said electrical circuit 102 is connected to said insulated part and parts connected thereto, and the other electrically conductive medium present directly or in the grinding gap via the other grinding member 22 by connecting the poles of the same grinding element to at least one other insulating part and at least one part connected thereto. The circuit 102 is arranged to be closed by an electrically insulating layer 42 between the parts having different poles which are overbridged via the other grinding member 22, so that the spacing between said grinding members can be directed by the electric current. 1. A device for measuring and controlling the distance between grinding members, characterized in that: 2. Device according to claim 1, characterized in that a measuring device 106 responsive to the spacing between the grinding members 22, 24 is connected to the circuit. 3. The device according to claim 1 or 2, characterized in that both poles of the power source 104 are connected to the fixed crushing member 24. 4. The device according to claim 2 or 3, characterized in that the measuring device 106 is constituted by an ammeter that reads or indicates the deflection when the electrical resistance changes between the insulating parts. 5 Control device 9 for adjusting the spacing between the crushing members 22, 24
4.98 is connected to a measuring device 106 so that the device can be automatically adjusted based on the measured value by the measuring device. . 6. Providing at least one separate electrical conductor in said one part of one of the grinding parts electrically isolated from other parts of the grinding device 10, said electrical conductor being passed through the grinding member 24 to the grinding surface. 6. The device according to claim 1, characterized in that it is an elongated device.