JPS58106381A - Method of controlling drying - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drying control method that automatically detects the degree of dryness of the material to be dried in the drying process of medicines, foods, etc. and allows the drying level to be adjusted as desired. It is something.

That is, the present invention is directed to a method of drying a material containing water using a ventilation type dryer, and includes the following methods: ,
■The output signal from the electric temperature measuring element installed in the dryness area or at the exhaust port, and ■The output signal from the detector that measures the humidity of the drying air used for drying are converted into signal numbers for these three systems. It is originally installed in a humidity detection control device equipped with means for calculating and detecting relative humidity, detects the relative humidity in the drying room, and stops drying when the relative humidity in the vending machine reaches a preset relative humidity value. The present invention relates to a method for controlling Ig drying, which is characterized by arbitrarily adjusting the degree of dryness of a material to be dried.

In the production of powders, granules, fine granules, tablets, etc. using the wet drop granulation method, it is extremely important to control the drying layer during the drying process. It is hoped that

The method of controlling dryness by measuring exhaust narrow humidity was an ideal method for controlling dryness. It is difficult to measure the humidity of the soft part stably, and it is virtually impossible to control the degree of dryness by measuring the humidity. In order to control the drying process to achieve the optimum drying condition, it is necessary not only to keep the open air during drying, drying temperature, and humidity of the drying air on the air supply side constant, but also to sample samples at random during drying. It was necessary to measure the moisture content of the material and dry it until it reached the optimum moisture content, and it was necessary to apply an electrolytic layer using an extremely labor-intensive method.

In other words, although it is important to optimally control the drying conditions in the drying process, it is extremely difficult both in terms of drying technology and equipment, and in the past it has been difficult to obtain products of consistent quality. is the current situation.

Therefore, the inventors of the present invention have conducted various studies on methods to arbitrarily control the degree of dryness by measuring humidity, which has been difficult in the past. It has been found that the relative humidity in the drying chamber can be determined by setting up a temperature measuring element and calculating from the eight factors of both temperatures and the absolute humidity on the air supply side using the relational expression described later.

In other words, the relative humidity is determined by a humidity detection control device equipped with an arithmetic circuit that derives the relative humidity based on the output codes from both electrical temperature measuring elements and the output codes from the detector that measures the supply air humidity on the air supply side. It turns out that it can be detected. The inventors have discovered that the present device H can easily and accurately detect the humidity that causes a delay in the drying process, and that the degree of dryness can be arbitrarily controlled, leading to the completion of the present invention.

In order to measure the change in temperature using this device, a suitable electrical temperature measuring element such as a thermistor or a resistance thermometer is used as the temperature sensing element. Since there is no interference from other causes, it is possible to measure the humidity inside a drying room where dust accumulates, which was previously impossible, and it has the revolutionary feature of being able to constantly detect humidity in a stable state. ing.

In other words, the present invention is an epoch-making device that makes it possible for the first time to detect humidity, which is an extremely important main factor in controlling the degree of dryness during drying. , the relative humidity during drying can be detected and the degree of dryness can be controlled arbitrarily, improving the quality of tablets, etc.

A method for calculating the relative humidity required to carry out the present invention will be described below.

Note that the relative m degree in the present invention is not taken as the relative humidity in the strict sense as long as it satisfies the control regarding the adjustment of the dryness of the material to be dried.

HD is the absolute humidity of the drying air used for drying.

When the temperature is TD, as the humidity in the drying chamber decreases, the temperature inside the drying chamber increases along the adiabatic cooling line. The absolute humidity when the temperature of the drying room reaches Tw is defined as Hw.

If the water vapor pressure in the drying room when the temperature of the drying room reaches Tw is Psv, the saturated water vapor pressure at PW, then the relative humidity R can be found from the following equation.

Psw of the Fi1 formula is determined from the formula (2) by applying Antoin's formula (Chemical Engineering Handbook, edited by Chemical Engineering Handbook, p. 26, p. 26).

The relational expression between PIIW and TW is (not limited to the following expression). Temperature TW and saturated water vapor pressure of water at that temperature TW P8w
If it is possible to find %, other formulas such as Frasius and Clapeyron's relational formulas may be applied.

(Equation 11 (D pw is known to be found from Equation (3).

Further, when the absolute humidity of the dry fluidized air is HD and the temperature is TD, the adiabatic cooling line is shown by equation (4), so the absolute humidity Hw at the temperature Tw in the drying chamber can be found by the equation (b).

CH(TD-Ty) = rw(HW-Hn) n1
CH: Moist specific heat (koal/Kg dry air °C) rW: T
It is known that #CH, which is the latent heat of vaporization of W (koal/water 1-), can be found using the equation (-).

CH-0,24+ 0.46HD (61ry is found by equation (7).

Above, PW is fil, +l), +6), +
HD, TD from 7j type.

A function with Ty as a variable. Psw is a function using TW as a variable from equation (2). Therefore, such HD
, TV, and TD as variables into a calculation circuit, the relative humidity R is calculated.

As for the location where the electrical temperature measuring element is installed, it is desirable to install it in the vicinity of the vent to the drying chamber in order to measure the temperature corresponding to the above-mentioned T[). The temperature corresponding to τ1 is preferably measured at a location inside the drying chamber, or may be installed near the exhaust port entrance. As the electrical temperature measuring element, an electrical measuring element such as a thermistor or a measuring resistor is used.

The aforementioned HD may be measured at any position between the air intake port and the vent to the drying chamber. Absolute humidity) ID detection measures the temperature of the rolling bulb and wet bulb according to the principle of wet and dry bulb humidity needles, and calculates the absolute humidity HD using an electronic circuit.
Detected as a yield of a porous sintered body of a polymer-11 material mainly composed of a conductive polymer or a metal oxide semiconductor,
An electronic circuit that calculates HD, or an electronic circuit made by chemically treating thin slices of plant pith and attaching electrodes) fD
HD is detected by a hygrometer that can calculate HD using an electronic circuit, such as one that calculates l(D) using an electronic circuit from the measurement of electrical conductivity, or directly using an absolute humidity needle. Can be measured.

Ventilation 11 using air as the main medium for carrying out the present invention
Dryers include a fluidized bed dryer that dries the material to be dried while fluidizing it with airflow within a tube body, a box IM (batch type) dryer, and a rotating drum with a reduced pressure ventilation drying mechanism. Examples include a reduced pressure ventilation drying device that performs drying while rolling. The present invention is limited to drying materials containing water.

The concentration detection control device of the present invention can calculate and detect the relative humidity during drying using the method described above, and can also store the relative humidity for stopping drying in advance. When the relative humidity reached reaches a preset relative humidity, a control signal can be sent to stop drying. When the dryness is controlled by the humidity detection of the present invention, a preset relative humidity can be transmitted. The above-mentioned HW is stored in the humidity detection control device.

When the relative humidity R calculated from Tl) and Tw reaches the above relative humidity, drying is automatically stopped. The stored relative humidity is a value determined separately through experimental trial and error, and is usually specified as a value in the range of 20 to 60 degrees.

The present invention will be briefly explained based on the embodiment shown in FIG. 1. FIG. 1 shows a control circuit for fluidized bed drying, 8 and 9 indicate electrical temperature measuring elements 10. and 11 is a transmitter that emits a signal proportional to the temperature measured by the electrical temperature measuring elements 8 and 9.

12 is a humidity detector for fluidized dry air; 18 is a humidity sensor for 12
This is a transmitter that calculates the humidity detected by the sensor into absolute humidity and emits a signal proportional to the absolute humidity. The electrical signals transmitted from each transmitter are input to the humidity detection controller W114, and the relative humidity is calculated by a calculation circuit in the humidity detection control chamber.The relative humidity can also be displayed by this device.

Furthermore, when the relative humidity calculated and detected by this device reaches the relative humidity stored in advance, a control signal is input to the controller 15 of the fluidized bed dryer to stop drying, and the exhaust fan is activated. It is also possible to stop the operation of the rotating electric motor 6 and stop the drying process.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention in the desiccant control method.
Figure 3 shows a schematic diagram illustrating an example. In Figure 1, 1 is an air intake for drying and fluidizing, 2
1 is a heat exchanger that heats the air from 1, 8 is a container for storing the material to be granulated or dried, 4 is the material to be dried, 5 is an electric motor for rotating the exhaust fan, and 6 is the material to be dried. A bag filter 17 that separates drying and fluidizing air represents an exhaust port. 8 windows and 9 are electrical temperature measuring elements, IO and 11 are temperature signal transmitters, 12 is a humidity sensor, 18 is an absolute humidity calculation transmitter, 14 is a humidity detection controller, and 15 is a fluidized dryer controller. show. 16 indicates a vent to the drying chamber. Note that the arrows in the figure indicate the flow of air, and the broken lines indicate the path of the detection signal, respectively. 1. Written amendment to the figure procedure (voluntary) Ushi January 22, 1980 1. Indication of the case 1982 Patent application No. 204966 2. Name of the invention Drying control method 3. Relationship with the supplementary +ni- person case Patent application Address 51'l'H5 Kitahama, Higashi-ku, Osaka City Name (
209) Mr. Hijikata, Representative of Purchase Chemical Industry Co., Ltd.
Takeshi 1 Agent Address: 5-15-6 Kitahama, Higashi-ku, Osaka Contents of amendment (1) The scope of claims for special ifF will be amended as shown in the attached sheet. (2) The specification shall be amended as follows. In the method of drying a material to be dried containing water using a ventilated dryer, there is provided an output signal from an electrical temperature measuring element provided at a vent to the drying chamber; Relative humidity is calculated based on the output signal from the electric temperature measuring element installed at the mouth, and the output signal from the detector that measures the humidity of the drying air used for drying. It is installed in a humidity detection control device equipped with a detection means, detects the relative humidity in the drying chamber, and when the relative humidity reaches a preset relative humidity, the dryness of the object to be dried is stopped. A drying control method characterized by forming sub-streaks on. 42

Claims (1)

[Claims] In the method of drying a material to be dried containing water using a ventilation type dryer, the following steps are taken: ■ An output signal from an electrical temperature measuring element installed at the vent to the drying chamber; Relative humidity is calculated based on the output signal from the electrical temperature measuring element installed at the mouth and the output signal from the detector that determines the supply humidity of the drying air used for drying. It is installed in a humidity detection control device equipped with a calculation detection means to detect the relative humidity in the drying room, and when the vending relative humidity reaches a preset relative value, the drying is stopped and the dryness of the item to be dried is checked. A drying control method characterized by arbitrary adjustment.