JP2616635B2 - Dry compression granulation method and apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for granulating powder by dry compression.

[0002]

2. Description of the Related Art Dry compression granulators are used in the field of handling powders, whether inorganic or organic, such as resins, chemicals, pigments, and the like.
It is used in a wide range of industrial fields, such as food, electronic components and other new materials. For example, in the manufacture of pharmaceuticals, dry compression granulators are often used because they can be molded under conditions with high productivity and little use of lubricants, which is desirable from the viewpoint of quality and easily conforms to pharmaceutical manufacturing standards. Have been. In other fields of use, compared to the wet granulation method using water and solvents, there are many opportunities to be adopted due to their quality and process advantages and the above reasons,
High productivity and stable quality of molded products are one of the decisive factors.

[0003] Therefore, the evaluation of the quality of a molded article is an important factor in use, and each user determines its own standard and manages the quality. Among the conventional technologies, the main ones are as follows. Generally, the crushing strength of the molded product, the density of the molded product, or the molded product is naturally dropped from a certain height by a certain amount and a certain number of times. The measurement of the drop strength for examining the degree of chemical conversion is widely performed. In each case, a test sample is sampled and measured under a certain condition by using another test facility. Therefore, this quality control does not go beyond the follow-up test of the molded product, and even if an abnormality is found, after many molded products have already been produced, real-time quality information that adjusts the operating conditions of the running equipment is obtained. It is hard to say what to give. For this purpose, a conventional technique has been developed in which a required numerical value is measured from a device in operation in order to stabilize the quality of a molded product, and the operating conditions are controlled based on the numerical value.

[0004] In Japanese Patent Publication No. 53-42474, irregularities are provided on the surfaces of a pair of rolls so as to mesh with each other.
A powder supply control device that supports the rotation axis of a roll with a spring spring, detects the roll interval by the pressure applied to the spring, and increases or decreases the number of rotations of the roll rotation motor based on the detected interval. . It states that this special roll shape has made the compression force uniform during powder compaction, and has further prevented leakage.

Japanese Patent Application Laid-Open No. 61-133133 discloses a method of controlling the strength of a molded product by variably adjusting the product of a roll linear pressure and a roll driving power while keeping the product constant. It is proposed that the linear pressure is adjusted by adjusting the roll pressing force, and the roll driving power is adjusted by adjusting the amount of powder pressed between the rolls. That is, a proportional relationship is established between the roll linear pressure and the strength of the molded product, and an inversely proportional relationship is established between the roll linear pressure and the thickness of the burr. Since a proportional relationship holds between
It is stated that if the product of the roll forming linear pressure and the roll power is kept constant and both are adjusted, the burr strength can be changed without changing the strength of the formed product.

Japanese Patent Publication No. 63-45615 discloses a method of controlling the roll torque by controlling the number of rotations of a screw and the number of rotations of a screw when the rotation speed of the screw reaches the upper limit rotation speed or the lower limit rotation speed of the screw. It is a proposal to control the roll torque by holding the number of rotations in front of it, and for that purpose, it has each adjuster and an arithmetic unit, and this arithmetic unit has a program function unit, a switch function unit, and a rotation speed holding function unit. It is characterized by being satisfied.

[0007]

The prior art exemplified here measures the dynamic elements of the apparatus during the operation of the apparatus and accepts the numerical values as information for controlling the quality stability. Obviously, it is no doubt that it has surpassed the level of management that used to be a sampling test that followed. However, in Japanese Patent Publication No. 53-42474, when the flow of the powder is not constant, a bridging phenomenon occurs and the flow stagnates and smooth operation does not continue. It is required to maintain a constant, and does not directly adjust the number of rotations of the screw for quality control of the molded product. Further, in Japanese Patent Application Laid-Open No. 61-133133, it is necessary to grasp in advance the roll linear pressure and the strength of the molded product, or the roll power and the strength of the molded product, and this relationship depends on the size of the apparatus. Naturally, they differ from each other, and even the same apparatus is affected by properties such as the particle size and shape of the powder, so that complicated adjustment is inevitable.
Also, in dry-type compression granulators, it is customary to attach a seal plate to prevent powder from leaking from the side of the roll, but for this reason, there is a high possibility that power unrelated to quality enters as an error. However, in this type of apparatus, it is often difficult for the power value to be an index directly indicating the strength of the molded article. As in the case of JP-B-63-45615, the roll torque is not affected by the seal plate or scraper of the apparatus, and is not always recognized as forming an accurate index as quality information of a molded product.

In other words, the dry compression granulation method of the prior art lacks an index for reliably ascertaining the quality of the molded article that is currently being collected, and therefore, it is necessary to maintain this quality constant or to obtain a desired quality. It is construed that there remains an unsolved major problem that there is no basic information to respond immediately when a change is required. In order to solve the problems described above, the present invention first finds an index that reliably captures the quality of a molded product flowing out of an operating apparatus, and performs dry compression that performs quality control in real time based on this index. An object of the present invention is to provide a granulation method and an apparatus therefor.

[0009]

In the dry compression granulation method according to the present invention, a powder P in a hopper 2 is pushed into a space between a pair of rolls 3 rotating in opposite directions by a rotating screw 1 and compressed. In a dry compression granulation method for molding,
The above problem has been solved by calculating the discharge density D of the molded article from the discharge volume V and the discharge weight W of the molded article due to the rotation of the roll, and controlling the quality of the molded article using the discharge density D as an index. In addition to this basic method, the pressing force p of the roll is adjusted in order to keep the discharge density D of the molded product constant, and in addition to this method, the thickness t of the molded product is kept constant. It is suggested that the object of the invention can be more effectively achieved by adding the adjustment of the rotation speed r of the screw for adjusting the rotation speed R of the screw to maintain the arbitrarily set molding ability. I do.

[0010]

Now, assuming that the discharge volume of the molded article is V and the weight discharged from the roll per unit time is W, the discharge density D of the molded article is calculated by D = W / V. Next, the discharge volume V can be calculated as follows: V = K1 × π × d × w × t × R Here, K1 is a unique constant, d is the diameter of the roll, w is the width of the roll, t is the thickness of the molded product, and R is the number of rotations of the roll. On the other hand, it is already known that there is a correlation as shown in FIG. 3 between the discharge density D of the molded product and the pressure p of the roll. More specifically, the pressing force p of the roll is generated by a hydraulic device and a hydraulic jack, so it is practical to substitute the pressure with the hydraulic pressure. From these two relationships, the discharge density D of the molded product is represented by the thickness t of the molded product,
Calculation is performed in real time by detecting the discharge weight W and the rotation number R of the roll, and the pressing force p of the roll is adjusted so as to keep the discharge density D constant even if disturbance occurs on the apparatus or the flow of the powder P. As a result, it is possible to continuously obtain molded products having a constant quality.

In the above equation for calculating V, if the action of adjusting the number of revolutions r of the screw is added in order to keep the thickness t of the molded product constant, the discharge per unit time due to the variation of the thickness t of the molded product is obtained. Since the occurrence of an error in the relationship between the volume V and the discharge weight W can be prevented, a more stable discharge density D of the molded product can be maintained.

Furthermore, under the above-mentioned complex control conditions, the thickness t of the molded article is controlled to be constant, so that D = W / R, Discharge weight W, that is, when the device is used to convert a powder to a predetermined molded product per unit time
The ability to mold are optionally co <br/> Control only by the rotational speed R of the roll, to come <br/> that might need to modify the molding ability, are also comprises immediately corresponding function.

[0013]

FIG. 1 is a block diagram showing one embodiment of the present invention. The powder P supplied to the dry-type compression granulator is pushed between two rolls 3A and 3B rotating in opposite directions at the lower portion by rotation of the screw 1 in the hopper 2. The rotation of the screw is driven by an electric motor 11 which is connected to an adjuster 12 for the rotational speed r of the screw, which is further connected to a setter 13 for the thickness t of the molded product, so that the The thickness t is specified by adjusting the rotation speed r of the screw as set.

Among the two rolls, the roll 3A has a fixed position, but the roll 3B can be moved in the horizontal direction, and the hydraulic mechanism 31 always moves in the direction to reduce the roll interval.
Is energized by The hydraulic mechanism 31 is connected to and controlled by a roll pressure adjuster 32, and the adjuster 32 is connected to the calculator 4. The powder P pressed between the rolls by the rotation of the screw is compacted by the pressure of the rolls and the rotation to form a sheet and squeezed out from between the rolls. 3B is pushed horizontally against the urging force, the distance between the rolls fluctuates according to the amount of bite, and the value of the thickness t of the molded product also fluctuates. The biting amount of the powder P is controlled by a regulator 12 of the screw rotation speed r, and the pressing force p of the roll is controlled by a hydraulic regulator 32. The thickness t of the molded product discharged from between the two rolls is measured by a sensor 33 for detecting the roll interval, and the sensor 33 is connected to the controller 12 and the calculator 4 of the screw rotation speed r and to a control system. Is composed. The roll receives a driving force for rotation by the electric motor 34. Since the rotation of the electric motor 34 is linked to the rotation speed R of the roll, the rotation speed is transmitted to the arithmetic unit 4, while
It is connected to an adjuster 51 which is connected to the molding capability setter 5 and is under its control.

The molded product discharged from between the rolls is crushed into granules having a predetermined particle size by a crusher 6 arranged below the roll, and the weight W discharged per unit time is measured on a measuring device 7. Is done. The meter 7 provides the data underlying the coupling to be molded ability <br/> force set controller 51 of the forming ability with important calibration values to the arithmetic unit 4.

As described above, the arithmetic unit 4 is connected to the controller 12 for the screw rotation speed r, the controller 32 for the roll pressing force p, and the information transmission path for the roll rotation speed R. Thus, it is directly connected to the setting device 41 of the emission density D and is the main component of a functional control system.

The control system of this embodiment is realized by combining analog information processing. However, a personal computer is introduced, the measurement from each part, and the measured value are A / D converted and input. It goes without saying that a digital method may be used in which the CPU performs a calculation and a comparison, and sends a signal for instructing each of the drive units the amount of fluctuation to be adjusted, thereby integrally controlling the amount of change.

An example of the procedure in actual work is as follows. First, in order to keep the thickness t of the molded product constant, the screw is set so that the thickness obtained from the sensor 33 for detecting the displacement of the roll becomes equal to the set value of the setter 13. Is automatically controlled. In order to maintain a constant quality, the signal value of the number of rotations R of the roll, the thickness t of the molded product, and the discharged weight W detected by the measuring device 7 are sent to an arithmetic unit, and the discharged density D is calculated instantaneously. The hydraulic pressure applied to the roll is automatically adjusted by the roll pressing force p adjuster 32 so as to match the calculated D and the value set in the discharge density setter 41. If these two controls are combined, a molded product of a constant quality can be stably obtained at a constant flow rate. Further, if the molding capacity is set by the molding capacity setting unit 5 under the conditions of this control, the regulator 51 of the rotation number R of the roll is operated until the molding capacity measured by the measuring device 7 matches the set value. To realize the desired molding ability.

The forming roll may be a flat roll as shown in FIG. 1 or a grooved roll having a groove cut into the surface of the roll. At this time, the discharge density D of the molded article can be obtained based on the above-mentioned formula and used as an index as it is for the control, but the coefficient K1 in the formula is corrected by the shape of the groove on the roll surface. And K2
There is also a method of calculating as

FIGS. 2A and 2B show an embodiment of the control of the dry compression granulator of the present invention. The roll diameter d is 110 mm, the roll width w is 35 mm, and the roll rotation speed is 0 to 110 rpm.
Is a variable expression. The oil pressure can be adjusted in the range of 0 to 280 kg / cm ² . As the raw material powder P, barium carbonate,
Automatic control operation was performed using gypsum and lactose. The progress of the operating values relative to time was fully interlocked as shown in the figure, demonstrating that the control system was functioning as planned.

[0021]

As described above, the dry compression granulation method according to the present invention newly establishes the discharge density D of a molded article as a universal index of quality, and is difficult to avoid in a granulation system. The quality of the molded product is always kept constant by adjusting the value of D to be constant with respect to disturbance, and further, the control for controlling the thickness t of the molded product to be constant by adjusting the number of rotations r of the screw is combined with the control. The function to continuously obtain high quality molded products was secured. Also, under this combined control, the forming capacity of the equipment is specified only by the number of rotations of the rolls, so it is possible to easily set and change the forming capacity. There are many effects such as improvement, application of unskilled workers, etc., and it can be expected that ultimately it will be a driving force to make a great progress toward factory FA.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a chart showing the progress of various values during operation according to the same embodiment according to (A) and (B).

FIG. 3 is a chart showing a relationship between a density of a molded product and a roll pressing force.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Screw 2 Hopper 3 Roll 4 Computing unit 5 Forming capacity setting unit 6 Crusher 7 Meter 11 Electric motor (for screw rotation) 12 Regulator (rotation speed r of screw) 13 Setter (rotation speed r of screw) 31 Hydraulic mechanism 32 Controller for the pressure p of the roll 33 Sensor 34 Electric motor (for rotating the roll) 41 Setter for the discharge density D 51 Controller for the molding capacity V Discharge capacity of the molded article W Discharge weight of the molded article D Discharge density of the molded article R Number of rotations of roll r Number of rotations of screw p Pressure of roll t Thickness of molded product P Powder

Claims (5)

(57) [Claims] A hopper (2) is rotated by a rotating screw (1).
In a dry compression granulation method in which the powder P in the inside is pressed between a pair of rolls 3 rotating in opposite directions to each other and compression-molded, the discharge volume V and the discharge weight W of the molded product due to the rotation of the rolls
A dry compression granulation method characterized in that the discharge density D of a molded article is calculated from the above, and the quality of the molded article is controlled using the discharge density D as an index. 2. The discharge density D of a molded product according to claim 1,
Wherein the pressure p of the roll is adjusted in order to keep the pressure constant. 3. The dry compression granulation method according to claim 2, wherein the rotational speed r of the screw is adjusted in order to keep the thickness t of the molded product constant. 4. The method according to claim 3, wherein the setting is arbitrary.
A dry compression granulation method comprising adjusting the number of revolutions R of a roll in order to maintain a molding ability. 5. A hopper 2 by a rotating screw 1.
In a dry-type compression granulator, the powder P inside is pressed between a pair of rolls 3 rotating in opposite directions and compression-molded.
Measuring means for measuring the number of rotations R of the roll, the thickness t of the molded product, and the discharged weight W, and control means for adjusting the pressing force p of the roll, the number of rotations r of the screw, and the number of rotations R of the roll based on the measurement. Dry compression granulator with a combined control system.