JP2528729B2 - Roll press - Google Patents

Description

TECHNICAL FIELD The present invention relates to a roll press for crushing limestone, cement raw materials, blast furnace slag, clinker and various chemical products, and particularly gives a great change to the particle size distribution of the crushed product. The present invention relates to a roll press capable of adjusting the ability without adjusting and correcting a deviation in which both rolls are not parallel during a crushing operation.

[Prior Art] Cement raw materials, coal, chemicals, blast furnace slag, and cement clinker are finely crushed, or as a preliminary crush for obtaining powder as a final product, a pair of rotating in opposite directions around a horizontal rotation axis. A roll press for crushing between cylindrical rolls is widely used.

In this roll press, the crushed raw material, which is arranged just below the hopper that stores the crushed raw material and fills the hopper discharge port and falls, is supplied just above the center between the two rolls, and at the boundary between the two rolls. Rotate in opposite directions towards the side,
And, it passes through the circumferential gap (hereinafter referred to as roll gap) between both rolls, which is crushed and crushed between the two rolls that are brought close to each other by the required pressing force to generate a substantially constant value during operation,
The product has a desired particle size and is dropped and discharged. In this case, the product particle size is the property of the pulverized raw material (grindability), the raw material particle size distribution,
It is regulated by factors such as the roll gap determined by the pressing force between the two rolls and the amount of raw material supply (capacity: weight / hour). Then, during operation, if some disturbance, such as the water content of the raw material or the raw material particle size distribution, changes, more raw material gets caught between both rolls, resulting in an increase in the roll gap, in other words, the product discharge amount. Although the raw material supply amount increased, the product particle size distribution became coarse due to the increase of the roll gap, and it became impossible to obtain a product having a desired particle size.

On the other hand, the above-mentioned roll gap does not have a difference in the axial direction and maintains a substantially uniform value during normal operation, but during operation, some disturbance causes deviation of the roll gap at the left and right ends of the roll. There is. For this cause,
Despite the fact that the positions of the hopper discharge ports are symmetrically arranged in the width direction of the roll, the particle size distribution of the pulverized raw material flowing down in the hopper is caused by the deviation in the width direction of the roll, and There is a cause due to a so-called asymmetry factor, in which heavy loads of the electric motor and the speed reducer, which are the driving devices of the side rolls, concentrate on only one side of the roll rotation shaft.

[Problems to be Solved by the Invention] Therefore, as a countermeasure against this, conventionally, the product particle size is returned to the original desired value by increasing the inter-roll pressing force to narrow the roll gap to the original value. However, since the easiness of biting the raw material is still good and the raw material supply amount does not decrease to the original value, the required power value of the electric motors for driving both rolls exceeds the rated power, and the excess value exceeds the limit. If exceeded, a motor trip will occur and operation will be suspended. Therefore, these countermeasures have their limits.

Also, when the deviation of the roll gap at the left and right ends of the roll generated in the roll press exceeds a certain limit value, the roll gap is the main factor that regulates the product particle size, so If the desired product cannot be obtained due to the spread of the particle size distribution, or the roll peripheral surface is unevenly worn, or if the deviation becomes extremely large, the movable side roll is designed to move in parallel. Each component causes a serious accident such as contact with the fixed roll press member and damage.

[Means for Solving the Problem] The above-mentioned two problems, that is, the crushing ability is changed by the disturbance such as the change of the crushing condition and the product particle size distribution is different from the desired one, and a large deviation in the roll gaps at the left and right ends In order to solve the problem that the product particle size distribution changes to a wider one than the desired one, in the roll press of the present invention, a pulverized raw material that is freely falling from the hopper discharge port is supplied,
Equipped with a pair of rolls that rotate around a horizontal axis, a pair of left and right bearings that support one roll rotation shaft are fixed, and a pair of left and right bearings that support the other roll rotation shaft are slidable in the axis-perpendicular direction. A roll press for arranging and connecting a hydraulic cylinder to each of the bearings to compress and pulverize the pulverized raw material on the adjacent peripheral surfaces of both rolls, and measure the gap between the left and right ends of the both rolls. When the gap sensor is arranged in the casing of the roll press and both the gaps are uniformly expanded, the gap sensor is uniformly expanded based on a preset relationship diagram between the roll rotation speed and the roll gap amount. A control device for controlling the roll rotation speed so as to restore the roll gap amount to the original roll gap amount is provided, and when the deviation between the two gaps exceeds a set value, a hydraulic operation circuit of the hydraulic cylinder is used. The left and right Thereby enabling changing the hydraulic pressure load pressure cylinder, and a roll press in which the rotation driving means of each roll and variable speed reduction motor.

[Operation] In the roll press of the present invention, the rotation speed of both rolls, which used to be a constant speed rotation, is changed to a variable speed by using a variable speed reduction motor, and between the rotation speed and the roll gap in the same crushing capacity operation. The number of rotations is changed by utilizing the fact that there is a correlation. In other words, the lower the roll speed, the larger the roll gap, and conversely, the higher the roll speed, the smaller the roll gap. Therefore, some disturbance during operation (most of them are pulverizability of raw materials and changes in water content). When the crushing capacity increases and the roll gap becomes large and the product particle size becomes coarse, the roll rotation speed is increased to narrow the roll gap and the roll gap is returned to the original state. Return to the one. Then, when the disturbance disappears, the rotation speed is reduced to restore the original operating state.

When the roll gap deviation (difference between the roll gaps at both ends) becomes larger than the set value due to the above operation or other reasons, the hydraulic pressure of the hydraulic cylinder that presses the left and right bearings of the movable roll is set to the hydraulic circuit. The larger roll gap increases the pressure by a certain width, and the hydraulic cylinder with the smaller roll gap decreases the pressure by the same width. By doing this, the specifications of both cylinders (cylinder diameter,
Stroke length etc.) is the same, the total pressing force of both cylinders is kept the same, but the larger roll gap advances more than the smaller roll gap, resulting in a deviation of both roll gaps. Decrease. The deviation is corrected within the set value by repeating the above operation several times by the feedback mechanism. Of course, during this operation, the roll speed does not change.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 4 show an embodiment of the present invention, FIG. 1 is a plan view of a roll press, FIG. 2 is a perspective view of the roll press,
FIG. 3 is an explanatory view of a roll gap generated between both rolls of a roll press, FIG. 3 (a) shows a normal state, and FIG. 3 (b) shows an abnormal state. FIG. 4 is a schematic hydraulic circuit diagram of a hydraulic cylinder for pressing the movable roll. FIG. 5 is a relationship diagram showing the correlation between the roll rotation speed and the roll gap.

In the figure, 1 is a roll press, 2 is a casing, and 2a.
Is a raw material charging port, 3 is a fixed roll, 3a is a bearing, 3b is a speed reducer, 3c is a variable speed motor, 4 is a movable roll, 4a is a bearing,
4b is a speed reducer, and 4c is a variable speed motor (not shown).

That is, both the fixed roll 3 and the movable roll 4 have a pair of bearings 3 that support a rotating shaft that rotates about a horizontal axis.
They are arranged in parallel in the casing 2 by a, 3a and 4a, 4a, and are driven via the variable speed motor 3c, V belt, speed reducer 3b and variable speed motor 4c, V belt, speed reducer 4b, respectively. The upper and lower hydraulic cylinders 5L, 5L are connected to the bearing 4a of the movable roll 4 on the left side when viewed from the movable side, and the other end is fixed to the frame 2c of the casing 2. Similarly, upper and lower hydraulic cylinders 5R, 5R are similarly connected to the right bearing 4a on the right side, and the other end is fixed to the frame 2c of the casing 2. The bearing 4a of the movable roll 4 is configured such that its bottom plate can slide on the frame 2d of the casing 2. The roll rotation speed change range is 5 to 30 rpm.

The rolls 3 and 4 have almost the same diameter and width, and the material is a forged steel product such as SF55. Hardened overlay is applied to the outer peripheral surface to improve wear resistance. Then, they are set to rotate in the opposite directions and rotate downward so that the raw materials that are caught in the adjacent peripheral surfaces move downward. The movable roll 4 has its bearing
4a, 4a are arranged so that they can slide in the direction perpendicular to the axis,
The left and right hydraulic cylinders 5L, 5L and 5R, 5R are provided with a pressing force for the material to be caught by the forward and backward movement of the piston rods, and the roll gap δ between both rolls can be adjusted.

Incidentally, both rolls are provided with mechanical stoppers so as not to damage the roll peripheral surface even if they come close to each other by the pressing force of the hydraulic cylinders 5L, 5L and 5R, 5R. It is designed to maintain a minimum clearance of 7 mm. Since the minimum clearance is increased by wear of the peripheral surface during use, an adjusting device capable of adjusting the clearance is separately provided.

The operation of the roll press of the present invention configured as above will be described.

After rotating both rolls 3 and 4 to the designed normal rotation speed as shown by the arrow in Fig. 2, for example, 14 rpm, hydraulic cylinders 5L and 5L
After setting the tension pressure of to a set value, for example 60 Kg / cm ² ,
When the crushed raw material filled in the hopper directly above the roll press is allowed to fall freely, the crushed pulverized raw material is distributed downwardly between the two rolls in an inverted triangular shape and rotates downward, and both rolls are brought closer by a hydraulic cylinder. Crushed by the pressing force applied in the direction
Fall through more. In this case, the rotation speed of the roll is constant, and the crushability of the raw material, the particle size distribution of the raw material, the water content of the raw material, the trapping angle corresponding to the apex angle of the substantially triangular shape of the raw material staying on the upper part of both rolls, and both rolls The correlation of the pressing force exerted between them determines the value of the roll gap δ, the product discharge amount (that is, the capacity: t / h), and the product particle size distribution.

If the above-mentioned crushing conditions (raw material properties, pressing force, raw material particle size, biting angle, etc.) are unchanged, the roll gap δ is almost constant, and the same roll gap is maintained in the axial direction between the circumferential surfaces. The normal operation that is maintained is continued (state of FIG. 3 (a)).

On the other hand, when the properties of the raw material change, for example, the water content of the raw material increases or the raw material size becomes coarse, the biting property between both rolls inevitably improves, and as a result, the capacity increases, resulting in normal operation. The roll gap δ of increases to δ ₁ ,
The product particle size becomes coarse.

In order to improve this state, in the roll press of the present invention, in order to restore the uniformly expanded roll gap δ ₁ to the original roll gap δ, the roll rotation speed is set to the conventional Nr.
Increase from pm to N ₁ rpm. By doing so, it was possible to cope with the increase in capacity due to the improvement of the biting property of the raw material,
The roll gap δ ₁ between the peripheral surfaces of the rolls, which is pressurized with the normal pressure, returns to δ. Actually, the operation of increasing the number of revolutions performed by receiving the signal value of the roll gap based on the information of the gap sensor 10 which is monitored for a certain period of time is a feedback system, and is gradually performed by several operations. Be improved. By thus restoring the roll gap to the state before the disturbance, the product particle size distribution is restored to the desired one.

When the disturbance disappears, the original operating conditions are restored by the above reverse operation.

The correlation between the roll rotation speed and the roll gap is roughly inversely proportional. Although it is a hyperbola or a straight line with a downward slope, it varies depending on the material to be ground, so it is desirable to collect data with a test machine or an actual machine for each ground material.

FIG. 5 shows the correlation between the roll rotation speed and the roll gap under each roll pressurizing condition when the blast furnace slag was crushed, obtained by an actual machine test. According to this, under a constant roll pressurization condition, the roll gap decreases as the roll rotation speed increases.

In the embodiment of the present invention, the roll driving means is a combination of a variable speed electric motor, a V-belt and a speed reducer, but of course a variable speed speed reducing electric motor may be adopted.

By the way, due to some disturbance, for example, the grain size of the raw material falling in the width direction of the roll is different due to the segregation of the raw material in the hopper (for example, when the raw material is coarse at the left end and fine at the right end). Hydraulic cylinders of the same specifications due to factors such as left-right symmetry in which the motor, V pulley, and reducer, which are heavy objects, are unevenly distributed on the left side of the movable roll 4 when the fixed side is viewed from the movable side.
Even if the same hydraulic pressure is applied to 5L and 5R, the left and right roll gaps δ _R and δ _L will show different values due to factors such as the left side being harder to move forward than the right side and the pressing force being reduced. FIG. 3 (b) state). This Δδ = δ _L −δ _R deviation within a certain limit, for example within 3 mm, is acceptable for operation, but as the limit value is exceeded, the product grain size differs at the left and right ends, and the product as a whole. The particle size distribution has a spread, which is different from the desired one.

Therefore, in the present invention, in order to correct such deviation, first, the gap sensor 10 is installed in the casing 2 at a position where the roll gaps δ _R and δ _L are measured, and the gap sensor 10 is measured at an appropriate time cycle during operation. Deviation Δδ = | δ _L
When −δ _R | exceeds the set value α, by giving a signal to the hydraulic unit 100 having the hydraulic circuit shown in FIG. 4 to make the hydraulic pressures applied to the left and right hydraulic cylinders 5L and 5R different,
It is configured to correct these deviations.

 Hereinafter, these functions will be described with reference to FIG.

In the figure, 104 is a relief valve, and the pressure oil from the oil tank 101 passes through the check valve by the pump 102 to the electromagnetic switching valve 106, and when the hydraulic cylinders 5L, 5R are desired to be moved forward or during operation, they are electromagnetically operated. SOL-1 of the switching valve 106 is excited and the left and right pressure reducing valves 10 are set to the same pressure, for example, 60 kg / cm ^2.
After passing through 7, the same hydraulic pressure is supplied to the left and right hydraulic cylinders 5L, 5L and 5R, 5R on the head side. Here, 110 is a flow rate adjusting valve. When it is desired to retract the hydraulic cylinders 5L and 5R, SOL-2 of the electromagnetic switching valve 106 is excited.

On the other hand, the roll gap [delta] _L, [delta] _{if R} deviation △ [delta] exceeds the set value, for example, as shown in FIG. 3 (b) δ _L>
When δ _R, the amplifier 109L gives a command to the proportional relief valve 108L to increase the pressure by an arbitrary step value, for example, 2 kg / cm ^{2, and} as a result, the left hydraulic cylinder
For example, 60 + 2 kg / cm ² of pressurized oil 62 kg / cm ² is supplied to the line A to the 5L, and conversely, the amplifier 109R gives the proportional relief valve 108R a command of ² kg / cm ² pressure reduction. The line B is supplied with 58 g / cm ² of pressure oil. After that, the deviation value by the gap sensor is compared with the set value, and when the deviation value is larger than the set value, the above operation is repeated until the deviation value is within the set value. In this way, even if the deviation of the roll gap exceeds the set value due to the disturbance, the correction is restored by the automatic control. In the figure, 111 is an accumulator, 112 is a suction filter, and 113 is an oil cooler.

As the gap sensor 10, for example, a non-contact type sensor using eddy current can be used, which is composed of a driver, a sensor, and a target, and a target directly connected to a movable portion penetrates into an annular sensor having a high frequency magnetic field. This is based on the principle that the impedance of the annular sensor changes depending on the position, and the relative position of the movable part can be measured by measuring the impedance of the sensor. The driver has the function of giving a high-frequency current of about 1MHz to the sensor via the oscillator, detector, and amplifier.

[Effects of the Invention] As described above, in the roll press of the present invention, the roll rotation speed is made variable, and even if the biting property between the rolls due to the disturbance of the raw material changes, the roll gap can be immediately dealt with. Since it can be kept constant, long-term stable continuous operation can be achieved without changing the product particle size, and the operability and maintenance of the device are significantly improved.

In addition, a gap sensor is provided so that even if the deviation of the left and right roll gaps between the roll peripheral surfaces exceeds a certain limit, the hydraulic pressures of the left and right hydraulic cylinders are automatically changed by stepwise differences via the hydraulic operation circuit of the hydraulic cylinders. Since the deviation is corrected by the control, the operation of the normal roll arrangement can be stably continued for a long time, so that the production efficiency is improved.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention. FIG. 1 is a plan view of a roll press, FIG. 2 is a perspective view of the roll press, and FIG. 3 is a roll gap formed between both rolls of the roll press. FIG. 3 (a) is a normal state, FIG. 3 (b)
Indicates an abnormal state. FIG. 4 is a schematic hydraulic circuit diagram of a hydraulic cylinder for pressing the movable roll. FIG. 5 is a relationship diagram showing the correlation between the roll rotation speed and the roll gap. 1 ... Roll press, 2 ... Casing, 3 ... Fixed roll, 3a ... Bearing, 3b ... Reducer, 3c ... Variable speed motor, 4 ... Movable roll, 4a ... Bearing, 4b ... … Reducer, 4c …… Variable speed motor, 5,5L, 5R …… Hydraulic cylinder, 10 …… Gap sensor, 100 …… Hydraulic unit, 102 …… Hydraulic pump, 106 …… Solenoid switching valve, 107L, 107R… … Pressure reducing valve, 108L, 108R… Proportional relief valve, 110… Flow control valve.

Claims (1)

(57) [Claims] 1. A pair of rolls, which are supplied with a pulverized raw material that freely falls from a hopper discharge port and rotate about a horizontal axis,
A pair of left and right bearings that support one roll rotation shaft is fixed, and a pair of left and right bearings that support the other roll rotation shaft are slidably arranged in the direction perpendicular to the axis, and hydraulic pressure is applied to each of the bearings. A roll press that connects cylinders and compresses and grinds the grinding raw material on the adjacent peripheral surfaces of both rolls, and a gap sensor that measures the gap between each of the left and right ends of the both rolls is provided in the casing of the roll press. When both the gaps are uniformly expanded, the uniformly expanded roll gap amount is set to the original roll gap amount based on the relationship diagram between the preset roll rotation speed and the roll gap amount. A control device for controlling the roll rotation speed so as to restore is provided, and when the deviation between the gaps exceeds a set value, the hydraulic pressure applied to the left and right hydraulic cylinders can be changed via the hydraulic operation circuit of the hydraulic cylinder. You With a roll press said a rotation driving means variable speed reduction motor for each role.