JPS6024760B2 - Pressure monitoring device in tablet press - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pressure monitoring device in a tablet press.

A normal tablet press has a rotary disk with a number of days formed at predetermined intervals along its periphery, and the upper and lower punches are placed in positions facing the upper and lower ends of the days, and the rotation of the rotary disk is Accordingly, after supplying the raw material powder or grains within the above-mentioned day, the powder, etc. is instantaneously pressurized with the upper and lower punches and molded into tablets, and the molded tablets are passed through the mortar by the raising of the lower punch. It is discharged from the inside to the outside.

In order to obtain homogeneous tablets in such tablet machines, it is extremely important to control the hardness, thickness, and weight of the molded tablets. There are various pressures at It is necessary to monitor the pressure of the lower pestle (hereinafter referred to as discharge pressure) when discharging from the bottom. This invention has been made in view of the above circumstances, and provides a device that can detect and record various pressures in a tablet press with high accuracy, and can also stop the tablet press based on detection of abnormal pressure. It is something to do.

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

The above-mentioned Honjo force and preload force of the upper punch can be detected in exactly the same way as those of the lower punch, and since the upper punch is not related to the discharge pressure, the following examples will only explain each pressure of the lower punch. do. In FIGS. 1 and 2, the Honjo force, preload force and discharge pressure are detected by strain gauges 11, 21 and 31, respectively.

The strain gauges 11 and 21 are attached to the rotary IJ cam of the tablet press that raises the lower punch at intervals, and the strain gauge 31 is attached to the oblique plate cam of the tablet press that raises the lower punch gradually. . Pressure signals based on resistance changes of these strain gauges 11, 21, 31 are transmitted to strain gauges 12, 2 having bridge circuits.
2 and 32, respectively, and then sent to peak voltage detectors 13, 23, and 33, respectively. The peak voltage detectors 13, 23, 33 are the strain meters 12, 22, 32.
It is reset by the rising edge of the pressure signal from , detects the peak value of the pressure signal, and holds this peak value until it is reset by the next pressure signal (see FIGS. 2B and 2C). Peak voltage detector 13, 2
The peak voltage signals of 3 and 33 are sent to pressure indicators 14, 24, and 34, respectively, each having an A-D converter, where they are converted into digital quantities, and then converted to pressure. Preload pressure and discharge pressure are displayed respectively. The tablet press is equipped with a punch detector 41.

Assume that there are 18 punches in the tablet press, and these are N.
, ~N, numbered up to 8. Then, an identification mark such as a magnetic piece is attached to the pestle N, and this is detected by the detector 41. The position detection signal A of the detector 41 is intensified by an intensifier 42, and then sent to a recording or observation device (described later).
(hereinafter referred to as a recording device) 19. Taking the actual pressure as an example, detection of the abnormal value and recording or observation of the actual pressure of the punches located before and after the punch that generated the abnormal value are performed as follows.

That is, the peak voltage signal C of the peak voltage detector 13 is converted into a digital quantity by the pressure indicator 14 and then sent to the upper and lower limit determiner 15. The upper limit level date and the lower limit level L are preset in digital values in this judger 15, and when the voltage signal C exceeds the upper limit level date or does not reach the lower limit level L, the abnormal pressure detection signal DH or D
Output L. When the voltage signal C is within the range of both levels L, no detection signal is output from the determiner 15, and the pressure is regarded as normal. Abnormal pressure detection signals O and D are alarms 1 consisting of buzzers, lamps, relay contacts, etc.
6 and an alarm is issued. The abnormal pressure detection signal is also sent to the display 14, and the abnormal pressure is displayed. Alarm 1
Preferably, the circuit 6 starts its operation in response to the signals DH and DL and continues its operation until a reset signal is sent by an external operation. Upper and lower limit determiner 1
The abnormal pressure detection signals DH and DL of No. 5 are sent to the timer 18 and the recording device 19 via the switch 1.

The timer 18 starts operating when the detection signal DH or DL is input, and operates for a predetermined set time T (for example, 5 to 15 seconds).
output signal E is generated after the lapse of time). When the detection signal DH or DL is input to this timer 8 during its operation,
From this point on, the clocking operation is started again, and the output E is generated after a time T from the above point. The recording device 19 is composed of, for example, an oscilloscope, an electron tube recorder, etc., and starts a recording operation when the detection signal DH or DL is sent thereto, and stops the operation according to the output E of the timer 19.
The timer 18 defines the operating time of the recording device 19. On the other hand, the pressure signal B of the strain gauge 12 is stored in the delay memory 1.
7) are directly input to the recording device 19 via the changeover switch 2.

The output terminal of the delay memory 17 is connected to the input terminal of the recording device 19 via the switch 2. Therefore, if the switch 2 is switched to the terminal b, the pressure signal B is directly input to the recording device 19, and if the switch 2 is switched to the terminal a, the pressure signal B is delayed by the predetermined time t (for example, several seconds) by the delay memory 7. and is input to the recording device 19. The pressure signals from the strain gauges 22, 32 and the detection signal A from the intensifier 42 are also input to the recording device 19 through the changeover switches 3, 4, 5, respectively. If both changeover switches and 2 are switched to terminal a, the detection signal DH of the determiner 15
, DL are sent to the timer 18 and the recording device 19, and the pressure signal B from the strain meter 12 is input to the recording device 19 after being delayed by a predetermined time by the delay memory 17. for example,
If the Honjo force of the punch with number N4 does not reach the lower limit level L, a detection signal DL is output from the determiner 15, and the timer 18 and the recording device 19 start operating based on this. Since the pressure signal B of the strain gauge 12 is sent to the recording device 19 via the delay memory 17, the pressure signal B from the previous pressure signal B by the delay time t caused by the delay memory 17 before the time when the detection signal D was output is A recording can be made or observed (from the pressure signal of the N2 pestle in FIG. 2). If the Honjo force applied by the N5 pestle also does not reach the lower limit level L, the determination unit 15 outputs the detection signal DL again, and the timer 18 starts counting again from this point.
Time T after the detection signal DL based on the pestle of N5 is output
Later, an output E is generated from the timer 18 and the recording device 19
stops the recording operation. A delay memory 43 is connected in parallel between the multiplier 42 and the recording device 19, the delay time of the parenthetical delay memory 43 is made equal to the delay time of the delay memory 17, and both switches 5 and 44 are connected to terminal a. If the position detection signal A is also delayed by the same amount of time and recorded, it is possible to determine which punch has generated the abnormal pressure. In this way, it is possible to record or observe not only the punch that generated abnormal pressure, but also the Honjo force of the punches located before and after that punch, making it possible to accurately diagnose the tablet press. ing. If both switches 2 are set to terminal b, the Honjo force can be recorded or observed simultaneously regardless of abnormal pressure detection, and if switch 1 is set to terminal a and switch 2 is set to terminal b, Simultaneous recording or observation of actual pressure after abnormal pressure occurs
In addition, by switching the switch to terminal b and the switch 2 to terminal a, it is possible to record or observe the main pressure delayed by the required time regardless of the occurrence of abnormal pressure.

Further, by switching the switches 3 and 4 to terminal a, the preload force and discharge pressure can be recorded or observed. In these cases, it is preferable to read the punch number by appropriately switching the switches 5 and 44. Note that it is also possible to connect an upper/lower limit determiner, a timer, a delay memory, etc. after the dynamic strain gauges 22, 32. FIG. 3 shows a case where the device according to the present invention is applied to a tablet production system.

In this example, the timer 54 starts operating based on the detection signal of the upper and lower limit determiner 15. The number of abnormal pressure occurrences is counted by the counter 51 during the set time of the timer 54, and when this reaches the required number, an alarm is issued.
At the same time, the relay circuit 53 stops the driving of the tablet press 61. Furthermore, based on the signals from the determiner 15 and the detector 41, the pestle number display 52 sequentially displays and records the number of the pestle that has generated the abnormal pressure. FIG. 4 shows a case where pressures of a plurality of tablet presses are monitored.

In this example, a plurality of tablet presses 61a, 61b...61n
Each of the instruments shown in Fig. 1 is equipped with the same numbers as those shown in Fig. 1, and the suffixes a and b are used to distinguish the tablet presses. . . . The description is omitted by adding n. This device is a sequential
It has scanners (multiplexers) 72, 73, 74 controlled by a timer 71. Peak voltage detector 1
The peak voltage signals of 3a, 13b...13n are:
The signals are sent to the scanner 72 via the display devices 14a, 14b, . . . , 14n. The scanner 72 switches the voltage in a fixed order at predetermined time intervals and sends it to the upper and lower limit determiner 15, where the peak voltage level is determined.If the upper and lower limit levels are outside the range of L, the detection signal is output and an alarm is issued. The central alarm device 75 has the same number of buzzers as the number of tablet presses, and is controlled by the timer 71, so that an alarm is emitted from the buzzer corresponding to the tablet press whose punch has generated abnormal pressure. Detectors 41a, 41b.・・・．・・４
1n output and dynamic strain meters 12a, 12b...1
The outputs of 2n are input to delay memories 7 and 43 through scanners 73 and 74, respectively, and sent to the recording device 19 after being delayed for a required period of time. The recording device 19 starts operating when the detection signal of the determiner 15 is input, and records the pressure signal and position detection signal from the tablet press having the punch that generated the abnormal pressure. As explained in detail above, according to the present invention, not only the honjo force but also the preload force and discharge pressure can be detected using a pressure detector such as a strain gauge, and the operation of the tablet press can be observed in detail using these. Since this enables various studies to be carried out based on this, it is possible to control the tableting operation more precisely. Since the peak voltage detector detects and holds the peak value of the pressure signal from the pressure detector, it is possible to display the pressure for each tablet compression, allowing for more precise monitoring. It becomes. Furthermore, since the peak voltage signal from the peak voltage detector is level-discriminated at a required level, it is possible to know for each tableting, that is, which punch has generated abnormal pressure. In addition, the pressure signal from the pressure detector is delayed by the required time and is input to the recording or observation device, and the abnormal pressure detection signal starts the operation of this recording or observation device to record or record the pressure signal. It is displayed. Therefore, it is possible to record or observe not only the punch that generated abnormal pressure, but also the pressure generated by several punches located in front of that punch, and from this, it is possible to examine in detail the process leading up to the generation of abnormal pressure. This makes it possible to greatly contribute to discovering the cause of malfunctions in tablet presses. In addition, since the operation of the recording or observation device is stopped by the output signal of a timer that measures a predetermined time from the output of the abnormal pressure detection signal, abnormal pressure is generated up to several punches located after the punch that generated abnormal pressure. Pressure can be recorded or observed, and the progress after abnormal pressure can be examined as well. Only the minimum amount of data necessary to investigate the cause of the abnormality is recorded or displayed, which avoids the complication of unnecessary data, and because there is no waste in recording or displaying, recording paper, etc. can be saved. You can save money.

[Brief explanation of drawings]

The drawings show an embodiment and an application example of the present invention, FIG. 1 is an overall block diagram of the embodiment, and FIG. 2 is a time chart showing output signal waveforms from each block in FIG. 1.
, FIG. 3 is a block diagram when this invention is applied to a tablet production system, and FIG. 4 is a block diagram when a large number of tablet presses are monitored by this invention. 11, 21, 31...Strain gauge, 12, 22, 32...
...Dynamic strain meter, 13, 23, 33... Peak voltage detector, 15... Upper and lower limit determiner, 17...
・Delay memory, 18...Timer, 19...
Recording or observation equipment. Figure 1 Figure N Ship diagram M Ship diagram dimensions

Claims (1)

[Claims] 1. A pressure detector that detects the pressure at required points in the tablet press, a peak voltage detector that detects and holds the peak value of the pressure signal from this pressure detector, and the required upper and lower limit levels are limited. , an upper and lower limit determiner that outputs an abnormal pressure detection signal when the peak voltage signal from the peak voltage detector deviates from the range of the upper and lower limit levels;
A timer that starts operating in response to the above abnormal pressure detection signal and generates an output after a predetermined time has elapsed; a delay memory that delays the pressure signal of the pressure detector by the required time and outputs it; A pressure monitoring device for a tablet press, comprising: a recording or observing device that starts operation according to the output of the timer, stops the operation according to the output of the timer, and records or displays an output signal of the delay memory during this time.