JPH0330424B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic film coating device for tablets, granules, etc.

For example, in a device that applies film coating to tablets, a spray gun for film coating liquid (hereinafter referred to as FC liquid) is placed inside a horizontal drum that holds a large number of tablets, and the drum is slowly rotated to agitate the tablets. It is known to spray FC liquid onto this using a spray gun.
In this case, the FC liquid tends to adhere to and accumulate on the FC liquid spout and its surrounding area, clogging it. Also,
Even if the FC liquid spout is not completely clogged, if the FC liquid adheres and its cross-sectional shape changes, the spray pattern of the FC liquid will be disrupted, and the FC liquid will not be sprayed uniformly onto the tablets. , there is a risk of producing a large number of defective tablets. For this reason, in the past, people constantly monitored the condition of the FC liquid ejected from the spray gun, and the FC liquid spout was clogged.
When the spray pattern of the liquid is disrupted, the equipment is stopped and the FC liquid spout of the spray gun is manually cleaned. In this way, with conventional film coating equipment, unattended operation is not possible, and each time an abnormality occurs in the FC liquid spout of the spray gun, the equipment must be stopped and cleaned manually, making it difficult to operate. Poor efficiency.

As a sensor for detecting the presence or absence of an object, there is a known optical sensor that consists of a light emitter and a light receiver that receives the emitted light. If installed on both sides of the front, it can be detected whether FC liquid is being sprayed from the spray gun. However, since the FC liquid ejected from the spray gun has a three-dimensional spread, it is not possible to detect disturbances in the spray pattern of the FC liquid using only one set of optical sensors. In order to detect disturbances in the spray pattern of FC liquid, it is necessary to arrange multiple sets of optical sensor emitters and receivers around the FC liquid spouted from the nozzle, which makes the sensor expensive. , space constraints are also significant. In addition, especially when film coating tablets, the drum is filled with differential particles generated from the tablets, and the presence of such fine particles reduces the amount of light transmitted between the emitter and receiver of the optical sensor. Because it changes,
Even if multiple sets of optical sensors are used to detect disturbances in the spray pattern of FC liquid, there is a risk that the optical sensors may malfunction due to fine powder, making it difficult to accurately detect disturbances in the spray pattern. is difficult.

This invention was made in view of the above-mentioned circumstances, and there is no fear that the FC liquid jet port of the spray gun will become clogged or that the FC liquid spray pattern will be disturbed, and in the unlikely event that the FC liquid spray pattern is disturbed. An object of the present invention is to provide an automatic film coating device that can easily and accurately detect such a situation using an inexpensive sensor and can be operated unmanned for a long time.

The automatic film coating device according to the present invention includes a spray gun that spouts FC liquid, and a cleaning nozzle that sprays cleaning liquid at predetermined time intervals to the FC liquid spouting port of the spray gun and its surrounding area. A sensor is installed in front of the film coating liquid spout to detect disturbances in the spray pattern of the film coating liquid spouted from the spout. It consists of temperature sensors placed around it.

According to the automatic film coating device of the present invention, the FC liquid spout of the spray gun and its surrounding area are cleaned at predetermined intervals, so there is a risk that the FC liquid spout may become clogged or the FC liquid spray pattern may be disrupted. There is no. And just in case the spray gun
When FC liquid adheres to the FC spout, a sensor can detect this as a disturbance in the spray pattern.
For example, since it is possible to take actions such as stopping the spraying of FC liquid, there is no need for humans to monitor the spraying status of FC liquid, and unmanned automatic operation for long periods of time, such as at night, becomes possible. In addition, since the sensor that detects disturbances in the spray pattern is a temperature sensor,
Disturbances in the spray pattern can be easily detected by simply placing it around the FC liquid. Therefore,
There is no need to arrange multiple sets of light emitters and light receivers as in the case of optical sensors, and the cost is low and space constraints are reduced. Further, even if fine powder is generated, the temperature sensor is not affected by the fine powder and can accurately detect disturbances in the spray pattern.

To the FC liquid supply pipe that supplies FC liquid to the spray gun.
It is desirable that a pressure sensor is provided to detect clogging of the FC liquid spout. If you do this, in case
When the FC liquid spout is clogged, it is detected and
For example, appropriate measures such as stopping the spraying of FC liquid can be taken.

In addition, it is preferable that the spray gun sprays out the FC liquid using air that is pumped from an air pump through an air supply pipe, and furthermore, this air supply pipe is equipped with a pressure sensor that detects abnormalities in the air pump. is desirable. In this way, in the unlikely event that an abnormality occurs in the air pump and the pressure of the air supplied to the spray gun decreases, this can be detected and an appropriate action such as stopping the spraying of FC liquid can be taken. measures can be taken.

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

Figures 1 and 2 show the overall configuration of an automatic film coating device for tablets.
A horizontal drum 2, into which a drum is placed, is placed inside the housing 3, and is rotated about its axis by a motor (not shown). A large number of small ventilation holes (not shown) are formed in the peripheral wall of the drum 2, and the housing 3 includes a supply tube 4 that supplies warm air for drying into the drum 2 through these small holes, and a supply tube 4 that supplies air from inside the drum 2. An exhaust pipe 5 for discharging hot air is provided, and each of these pipes 4 and 5 is provided with a fan and a damper (not shown) for adjusting the air volume.

A rod-shaped spray gun support member 6 parallel to the drum 2 is attached to the housing 3 so as to be movable in its length direction, and can be moved in and out of the drum 2 from one end thereof. Three sets of spray guns 7, cleaning nozzles 8, and temperature sensors 9 are attached to this support member 6. These are arranged at predetermined intervals in the length direction of the support member 6, and are arranged in the drum 2 when the support member 6 enters the drum 2.

As shown in detail in Figures 3 to 5,
An FC liquid passage 10 is provided in the center of the spray gun 7, and a narrower FC liquid ejection port 11 is formed at the front end of this passage 10 so as to face forward. Also,
A needle 12 for opening and closing the spout 11 is provided in the FC liquid passage 10 so as to be movable back and forth. Front projections 13 are provided at symmetrical positions with respect to the FC liquid jet ports 11 on both sides of the front surface of the spray gun 7, and an air jet port 14 facing forward and inward is formed at the front end of each projection 13. ing. In addition, the protrusion 13 and
A plurality of forward air jet ports 15 are also formed between the FC liquid jet port 11, and these air jet ports 14,
15 is connected to an air passage 16 provided around the FC liquid passage 10 in the spray gun 7.

As shown in detail in FIG. 3, the cleaning nozzle 8 is arranged diagonally in front of the spray gun 7. A cleaning liquid passage 17 is provided in the center of the nozzle 8, and a cleaning liquid jetting port 18, which is narrower than this, is formed at the front end of this passage 17. An air passage 19 is provided around the cleaning liquid passage 17, and an air outlet 20 is formed at the front end of this passage 19. The cleaning liquid spout 18 and the air spout 20 face the FC liquid spout 11 of the spray gun 7, and the pair of protrusions 1
The cleaning liquid is sprayed from 3 to the FC liquid spout 11.

As shown in detail in FIGS. 3 and 5, the temperature sensor 9 consists of four platinum resistance wires 21 connected in a diamond shape and is arranged in front of the spray gun 7 at right angles thereto. . Four electric wires 23 are connected between the resistance wires 21 from a control device 22, and a Wheatstone bridge is formed by these wires.

An FC liquid tank 24 is arranged outside the housing 3, and a stirrer 2 equipped with a motor 25 is installed inside this tank 24.
6 is provided. An FC liquid supply pipe 27 is provided between the FC liquid tank 24 and the FC liquid passages 10 of the three spray guns 7.
In order from the 4th side: Y-type strainer 28, valve 29, capacitance type proximity switch 30, FC liquid pump 31
and a pressure sensor 32 are provided. The proximity switch 30 detects the end of the FC liquid,
Its output signal line 33 is connected to the control device 22. In addition, the proximity switch 3 of the FC liquid supply pipe 27
The portion corresponding to 0 is a synthetic resin pipe 34. The pressure sensor 32 detects clogging of the FC liquid ejection port 11 of the spray gun 7, and its output signal line 35 is connected to the control device 22. A pipe cleaning liquid tank 36 is arranged above the FC liquid tank 24, and a cleaning liquid supply pipe 37 from this tank 36 to the FC liquid tank 24 is connected to a control device 22.
A solenoid valve 38 is installed which is operated by.

A spray gun cleaning liquid tank 39 is arranged outside the housing 3, and a cleaning liquid supply pipe 40 is provided between this tank 39 and the cleaning liquid passage 17 of the cleaning nozzle 8. A strainer 41 and a solenoid valve 42 operated by the control device 22 are attached to the pipe 40 in this order from the tank 39 side.

An air pump 43 is arranged outside the housing 3, and branch air supply pipes 45 and 46 branched from the main air supply pipe 44 of this pump 43 are connected to air passages 16 and 19 of the spray gun 7 and the cleaning nozzle 8, respectively. has been done. The main air supply pipe 44 is provided with a pressure sensor 47 that detects an abnormality in the air pump 43, and each branch air supply pipe 45, 46 is provided with a solenoid valve 48, 49 operated by the control device 22, respectively. installed. An output signal line 50 of this pressure sensor 47 is connected to the control device 22.

Although not shown in the drawings, each part of the automatic film coating apparatus is provided with sensors, switches, etc. for detecting various abnormal developments as will be described later. The control device 22 is equipped with a microcomputer and controls the entire device to automatically perform the film coating operation, as will be described below.

When performing film coating work, beforehand, pour FC liquid into the tank 24 and
Cleaning liquid is placed in tanks 36 and 39, respectively. As the FC liquid, various materials similar to those used in conventional film coating equipment can be used, such as polymers, dyes, and plasticizers dissolved in water or organic solvents. The amount of FC liquid to be put into the tank 24 is determined from the amount of FC liquid per tablet and the number of tablets to be film coated. Further, as the cleaning liquid, an appropriate material can be used, such as a mixture of ethyl alcohol and water, or a mixture of ethyl alcohol and methylene chloride. The amount of cleaning liquid to be put into the spray gun cleaning liquid tank 39 is determined by taking into account the number of cleanings, time, etc.

When the above criteria are completed, a predetermined amount of tablets 1 are placed in the drum 2, a spray gun 7 or the like is placed in a predetermined position in the drum 2, and the start button is pressed. As a result, the control device 22 controls the drive motor of the drum 2, the fan and damper of the supply cylinder 4 and the exhaust cylinder 5, the needle state 12 of the spray gun 7, the stirrer 26 of the FC liquid tank 24, the FC liquid pump 31, and the air pump. 43 and each solenoid valve 38, 42, 4
8, 49, etc., to automatically perform the film coating work.During the work, the output of each sensor 9, 32, 47, switch 30, etc. is monitored, and if abnormal development is detected, the following measures are taken. Take.

When the start button is pressed, the dampers of the intake pipe 4 and the exhaust pipe 5 open to start the heater, air supply fan, and exhaust fan, and the drum 2 rotates at a low speed (for example, 4 rpm), thereby uniformly distributing the tablets. is stirred. Drum 2 rotates at a low speed for a certain period of time, and then rotates at a high speed (for example, 8 rpm).
At the same time, the FC liquid and air are supplied to the spray gun 7, and the FC liquid is continuously sprayed onto the tablet 1 for a certain period of time (for example, several minutes). At this time, the FC liquid discharged from the FC liquid jet port 11 of the spray gun 7 is atomized by the air jetted forward from the air jet port 15, and also by the air jetted obliquely from the air jet port 14. It is spread out into a fixed pattern with an oval cross section and is uniformly sprayed onto the tablet 1 through the inside of the temperature sensor 9. Then, each time the FC liquid is sprayed continuously for a certain period of time, the supply of the FC liquid and air to the spray gun 7 is stopped, and the spraying of the FC liquid is interrupted.
During this time, the spray gun cleaning liquid and air are supplied to the cleaning nozzle 8 for a certain period of time (for example, several seconds), and the spray gun 7 is cleaned. At this time, the cleaning liquid discharged from the cleaning liquid spout 18 of the cleaning nozzle 8 is sprayed onto the FC liquid spout 11 of the spray gun 7 and its surrounding area by air jetted from the air spout 20 to clean it. When the cleaning of the spray gun 7 is completed, the spraying of the FC liquid starts again in the same manner as described above, and thereafter, the spraying of the FC liquid and the cleaning of the spray gun 7 are continued for a predetermined period of time until the FC liquid in the tank 24 is exhausted. repeated every other time. During this automatic film coating operation, the rotational speed of drum 2 and
The discharge amount of the FC liquid pump is changed at predetermined intervals.

When the FC liquid in the tank 24 runs out, the control device 22 detects this by a change in the output of the proximity switch 30, and after a certain period of time has passed, opens the solenoid valve 38 of the pipe cleaning liquid supply pipe 37 to remove the cleaning liquid and air. is supplied to the spray gun 7. As a result, the cleaning liquid is sprayed onto the tablet 1, and the insides of the FC liquid tank 24, FC liquid pump 31, FC liquid supply pipe 27, and spray gun 7 are cleaned. After these washings are completed, the drum 2 is decelerated (for example, to 4 rpm), and the tablets 1 are kept constant by hot air supplied from the supply cylinder 4 into the drum 2 and discharged through the exhaust pipe 5. Dry for an hour. Once the drying of Tablet 1 is completed, in order to ensure drying,
Intermittent driving is performed in which the drum 2 is rotated and stopped at predetermined intervals. This intermittent driving of the drum 2 is to prevent the film-coated tablets 1 from adhering to each other, and continues until the drum 2 is stopped by manual operation by an operator.

In this way, the FC liquid spout 11 of the spray gun 7 is cleaned every time the FC liquid is sprayed for a certain period of time, so there is no risk that the spout 11 will become clogged or the FC liquid spray pattern will be disrupted. . However, during the above film coating operation, the control device 22 constantly monitors for disturbances in the spray pattern of the FC liquid, clogging of the FC liquid spout 11 of the spray gun 7, abnormalities in the air pump 43, and other abnormalities in development. .

Disturbances in the spray pattern of the FC liquid can be detected by the temperature sensor 9.
It is detected as follows. When the spray pattern of the FC liquid is normal, the atomized FC liquid passes inside the temperature sensor 9, and the distances from each resistance line 21 of the temperature sensor to the outer periphery of the FC liquid are approximately equal to each other. Therefore, each resistance wire 21
The temperatures, or resistance values, are almost equal to each other, and the equilibrium of the Wheatstone bridge is maintained. On the other hand, the spray pattern of the FC liquid is disrupted, resulting in a mist of FC.
If the liquid is biased to one side of the temperature sensor 9, a difference will occur in the distance from each resistance wire 21 to the outer circumference of the FC liquid,
In some cases, a portion of the resistance wire 21 is sprayed. For this reason, a difference occurs in the temperature of each resistance wire 21, and the equilibrium of the Wheatstone bridge is disrupted.
As a result, disturbances in the spray pattern of the FC liquid are detected. While the spraying of FC liquid is interrupted, the FC
The spray pattern of the liquid is not monitored.

A clogging of the spray gun 7 or an abnormality of the FC liquid supply pipe 27 is detected by the pressure sensor 32 in the following manner. FC liquid spout 11 and other parts of spray gun 7 and FC liquid supply pipe 2
7 becomes clogged, the pressure at the pressure sensor 32 becomes abnormally high, and if the FC liquid leaks from the FC liquid supply pipe 27, the pressure at the pressure sensor 32 becomes abnormally low. . Therefore, these abnormal phenomena are detected by changes in the output of the pressure sensor 32. These abnormal phenomena are not monitored while the spraying of FC liquid is interrupted.

An abnormality has occurred in the air pump 43 and the spray gun 7
When the pressure of the air supplied to the air pressure sensor 47 decreases, this is similarly detected by a change in the output of the pressure sensor 47.

If any of the above abnormal phenomena occur during automatic film coating work, first stop spraying the FC liquid, dry the tablets 1 with warm air for a certain period of time, then slow down the drum 2. The drum 2 is driven intermittently in the same manner as described above. In this way, defective tablets will not be produced, and film coating can be performed again after appropriate measures are taken against abnormal phenomena.

Further, during the film coating work, the control device 22 monitors the load on the FC liquid pump 31 and the exhaust temperature in the exhaust pipe 5, and measures the working time. As described above, the discharge amount of the FC liquid pump 31 is changed as appropriate during work, but the control device 22 monitors whether the discharge amount has been changed as instructed. If the motor of the FC liquid pump 31 becomes overloaded, if the exhaust temperature exceeds the set range, if the FC liquid in the tank 24 does not run out even after a certain period of time has passed from the start of work, or if the FC liquid pump If the discharge amount of 31 is not changed as instructed, a series of steps similar to those described above are carried out to interrupt the film coating operation and prevent the production of defective tablets.

Further, the control device 22 monitors the damper openings of the supply cylinder 4 and the exhaust pipe 5 and the loads of the motors of the supply fan and the exhaust fan during the film coating operation. Then, if the damper is not open when it should be open, if the damper opening is not changed even though it is commanded to change, or if the intake fan or exhaust fan motor is overloaded. In this case, the spraying of the FC liquid is first stopped, the drum 2 is decelerated and rotated for a certain period of time, and then the drum 2 is driven intermittently in the same manner as described above.

Further, the control device 22 monitors the load on the drum 2 speed change motor and the rotational speed of the drum 2 during the film coating operation. If the speed change motor is overloaded or the drum 2 is not accelerated or decelerated as instructed, first stop spraying the FC liquid and blow the tablets 1 with hot air.
After drying for a certain period of time, if the drum 2 is rotating at a low speed, the same intermittent drive as described above is performed, otherwise the drum 2 is stopped.

In addition, the control device 22 monitors the power supply and the load on the drive motor of the drum 2 during film coating work, and stops spraying the FC liquid in the event of a power outage or when the drive motor is under load. At the same time, stop the entire device. If a power outage occurs while the drum 2 is rotating at a low speed, the same intermittent drive as described above is performed after the power outage is restored.

Further, the control device 22 monitors the number of rotations of the drum 2 and clocks the continuous rotation time of the drum 2 during the intermittent driving of the drum 2 . Then, if the drum 2 is rotating at a speed other than the low speed, or if it is continuously rotating beyond the set time, the drum 2 is stopped immediately.

As described above, according to this automatic film coating device, if there is no abnormality in each part of the device, the film coating work that repeats spraying the FC liquid and cleaning the spray gun 7, cleaning the piping, and performing the film coating drying of tablet 1,
A series of operations of intermittent driving of the drum 2 are performed automatically, and if an abnormality occurs, the film coating operation is interrupted and the generation of defective tablets is prevented by taking appropriate measures according to the abnormal phenomenon. Ru.
Therefore, there is no need for a person to monitor the device during work, and long-term automatic operation is possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall configuration diagram showing a schematic cross section of the housing of the device and a pipe system;
Fig. 2 is a schematic vertical sectional view of the housing, Fig. 3 is a partially cutaway side view of the spray gun, cleaning nozzle, and temperature sensor, Fig. 4 is a sectional view taken along the line of Fig. 3, and Fig. 5
The figure is a view in the direction of the arrows of FIG. 3--line. 7... Spray gun, 8... Cleaning nozzle, 9...
...Temperature sensor, 11...Film coating liquid spout, 27...Film coating liquid supply pipe, 32...Pressure sensor, 43...Air pump,
44, 45...Air supply pipe, 47...Pressure sensor.

Claims (1)

[Claims] 1. A spray gun 7 that sprays a film coating liquid, and a cleaning nozzle 8 that sprays a cleaning liquid onto the film coating liquid spout 11 of the spray gun 7 and its surrounding area at predetermined intervals, A sensor 9 is provided in front of the film coating liquid spout 11 of the spray gun 7 to detect a disturbance in the spray pattern of the film coating liquid spouted from the spout 11. An automatic film coating device consisting of a temperature sensor placed around the inside of which the liquid passes. 2. In the film coating liquid supply pipe 27 that supplies the film coating liquid to the spray gun 7,
The automatic film coating apparatus according to claim 1, further comprising a pressure sensor (32) for detecting clogging of the film coating liquid spout (11). 3. The spray gun 7 sprays the film coating liquid using the air pumped from the air pump 43 through the air supply pipes 44 and 45. 3. The automatic film coating apparatus according to claim 2, further comprising a pressure sensor 47 for controlling the pressure sensor 47.