JP3455813B2 - Method and apparatus for drying ceramic moldings - Google Patents

Description

Detailed Description of the Invention

The present invention relates to a drying apparatus for ceramic moldings such as roof tiles, tiles and bricks.

[0002]

2. Description of the Related Art Ceramic products such as roof tiles, tiles and bricks are generally manufactured from a raw material composed mainly of clay containing moisture. The moisture content of the ceramic molding immediately after molding is about 20%. Therefore, it is known that it is necessary to dry the ceramic molding. When the ceramic molded product is dried, it is inevitable that the ceramic molded product will shrink due to the drying.

In particular, in the case of so-called forced drying, which uses hot air widely used in the industry, there is a possibility that a difference in shrinkage due to this drying may occur remarkably. It was a cause of deformation and cracks. Therefore, it is important to properly control the drying of the ceramic molding in order to prevent deformation and cracks in the ceramic molding. It was a big factor to realize.

Drying of ceramic moldings can be divided into three periods: a preheating period, a constant rate drying period, and a decreasing rate drying period.

During the preheating period, the temperature of the ceramic molding rises,
It refers to the period until the temperature is kept constant. The preheating period is
This is a period during which the temperature of the ceramic molded article rises due to the hot air supplied into the drying furnace, and most of the heat of the hot air is spent on increasing the temperature of the ceramic molded article and not on the drying of the ceramic molded article.

[0006] However, if the surface of the ceramic molded product is dried before the temperature inside the ceramic molded product rises, the water inside the ceramic molded product cannot move sufficiently, so that a significant shrinkage due to the drying occurs. A difference occurs, and this remarkable difference in shrinkage causes deformation and cracks in the ceramic molding.

Therefore, it is required to raise the temperature of the ceramic molding as much as possible in order to suppress the drying from the surface of the ceramic molding while shortening the drying time.

The constant rate drying period is a period from when the temperature of the ceramic molded product is kept substantially constant to when the moisture content of the ceramic molded product reaches the critical moisture content. During the constant rate drying period, the temperature of the ceramic molding remains almost constant, but the moisture inside the ceramic molding evaporates from the surface of the ceramic molding and the moisture inside the ceramic molding is adjusted to follow the evaporation of water from the surface. It is in a state of moving toward the surface. Therefore, in the constant rate drying period, the ceramic molding is dried at a substantially constant drying rate until the moisture content of the ceramic molding reaches the critical moisture content.

Generally, the higher the temperature of the ceramic molded product, the more the amount of water that migrates from the inside of the ceramic molded product to the surface. However, simply raising the temperature in the drying oven to raise the temperature of the ceramic molding increases the amount of water that evaporates from the surface, while the water that moves from the inside to the surface corresponds to the water that evaporates from the surface. Will not be able to follow.

Therefore, a difference occurs in the dry state between the surface and the inside of the ceramic molded article. As a result, the ceramic molded product undergoes a significant difference in shrinkage due to drying, and the ceramic molded product is deformed or cracked. Therefore, in the constant rate drying period, it is important to prevent the difference in shrinkage due to drying from occurring in the ceramic molded article as much as possible.

The rate-reduced drying period refers to a drying period until the moisture content of the ceramic molding reaches from the critical moisture content to the equilibrium moisture content. During the rate-decreasing drying period, the amount of water evaporated from the surface of the ceramic molding becomes larger than the amount of water that moves from the inside to the surface, and the drying speed decreases as the water remaining in the ceramic molding decreases. During the rate-decreasing drying period, the temperature of the ceramic molding rises, and when the moisture content of the ceramic molding reaches the equilibrium moisture content, the drying of the ceramic molding ends. During the rate-decreasing drying period, the shrinkage of the ceramic molded product hardly occurs, so that the ceramic molded product is less affected by deformation and cracks due to the drying.

Next, a conventional drying apparatus of this type will be described together with a drying method. In the drying device shown in FIG. 6, a hot air supply passage having a burner i is connected to a drying furnace a for containing a ceramic molded product which is wet-molded, and the temperature inside the furnace is provided in the drying furnace a. The sensor k controls the combustion amount of the burner i based on the detected value of the furnace temperature and the set value of the furnace temperature to adjust the temperature in the drying furnace.

A humidifier j provided in the hot air supply passage for mixing steam into the hot air, a hot air humidity sensor r for detecting the relative humidity of the hot air to be supplied, and a temperature of the hot air to be supplied are detected. Hot air temperature sensor p, the set value of the furnace relative humidity, and the absolute humidity is calculated from the detected value of the furnace temperature by the furnace temperature sensor k or the set value of the furnace temperature, further,
The absolute humidity is calculated by calculating the relative humidity at the temperature of the hot air obtained by the hot air temperature sensor p and outputting the calculated value as a correction value for the relative humidity.

Further, there is provided control means s for controlling the amount of steam mixed in the humidifier j based on the difference between the detected value of the hot air humidity sensor r and the correction set value obtained by the calculation means.

According to this apparatus, when controlling the relative humidity of the drying oven a, the set value of the oven relative temperature preset by the calculating means t and the value of the oven temperature detected by the oven temperature sensor k or The absolute humidity is calculated from the preset value of the furnace temperature, and the relative humidity at the temperature of the hot air obtained by the hot air temperature sensor p is calculated for that absolute humidity, and the calculated value is the correction value of the relative humidity. Is output as.

Subsequently, in the control means s, the detected value of the relative humidity of the hot air obtained by the hot air humidity sensor r is compared with the correction set value output from the arithmetic means t, and based on the difference. The amount of steam mixed in the hot air from the humidifier j is controlled, and the relative humidity of the hot air is controlled to the correction set value.

In this case, the amount of steam mixed into the hot air is controlled in anticipation of changes in the furnace temperature and changes in the furnace relative humidity, so that the furnace temperature changes. The relative humidity in the furnace is accurately adjusted to the set value.

Therefore, since the relative humidity in the furnace is controlled more accurately and delicately, it is possible to prevent breakage and deformation even in a ceramic molded article having a complicated shape to improve the drying yield, and to improve the drying time. It is said that it has advantages such as further shortening.

However, in the above-mentioned conventional technique, the temperature in the drying oven is measured, and the temperature in the drying oven is controlled based on the difference between the measured oven temperature and the set value of the oven temperature.
In order to maintain the set relative humidity in the drying oven, the relative humidity of hot air is controlled using a humidifier. That is, the temperature control in the drying furnace is performed by the hot air heating control, and the relative humidity in the drying furnace is controlled by the steam mixing amount of the hot air.

However, if the temperature of the hot air is controlled to control the temperature inside the drying oven, the relative humidity of the hot air follows and changes, and the relative humidity inside the drying oven changes. Therefore, although steam is mixed according to the change in relative humidity and maintained at the set relative humidity, the following procedure is required to control the amount of steam appropriately. Determine the absolute humidity from the set value of the relative humidity in the furnace and the measured value of the temperature in the furnace. The temperature of the hot air is measured, and the relative humidity as a correction set value is obtained from the measured value of the temperature of the hot air and the calculated absolute humidity in the furnace. The measured value of the humidity of the hot air measured by the hot air humidity sensor is compared with the correction set value. The amount of steam mixed is controlled according to the comparison result.

As described above, since controlling the temperature in the drying furnace by controlling the temperature of the hot air has a close and complicated relationship between the temperature and the relative humidity, the relative humidity should be adjusted so as to correspond to the change in temperature. Therefore, the control of relative humidity in the drying furnace becomes complicated, and it is extremely difficult to find the conditions for achieving optimum drying of the ceramic molding.

Therefore, the control of the drying for realizing the optimum drying is limited to those who are familiar with the drying technique such as the designer of the drying apparatus, and the operator engaged in the production of the ceramic molded article is the ceramic molded article. It was impossible to freely change these controls according to changes in the.

[0023]

The problem to be solved by the present invention is that the conventional drying technique controls the temperature of the hot air to control the temperature inside the drying furnace, while steam is mixed into the hot air to dry the drying furnace. In order to control the relative humidity inside, the change in relative humidity is taken into account to correspond to the change in temperature due to the point that complicates the control of relative humidity in the drying furnace and the close and complicated relationship between temperature and relative humidity. In addition to the fact that it is not possible to control temperature and relative humidity individually, it is also difficult to find the conditions for achieving optimal drying of ceramic moldings. The control of relative humidity and temperature is limited to those who have specialized knowledge of drying.

The object of the present invention is to achieve optimum drying of the ceramic molding, and to separately control the temperature of hot air and the supply amount to facilitate the optimum drying control of the ceramic molding. Another object of the present invention is to provide a drying device for a ceramic molded product, which allows an operator of a drying furnace having no special knowledge or experience in drying control to easily control the drying conditions.

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

Means and effects of the order to achieve the above eye
In order to achieve the object, the drying device for the ceramic molded article according to claim 1 is provided with a drying furnace for accommodating the wet molded ceramic molded article, and a hot air supply source is provided in a hot air supply duct connected to the drying furnace. In a ceramic molding drying device in which an outside air suction duct is connected to the hot air source and an exhaust duct is connected to the drying furnace, an outside air temperature sensor that measures the temperature of the outside air and an outside air humidity sensor that measures the relative humidity of the outside air There is provided in the outside air suction duct, the outside air relative humidity measured by the outdoor air temperature and outdoor air humidity sensor which is measured by the outside air temperature sensor
More, the calculating means is provided to determine the target temperature of the hot air corresponding to the set wet-bulb temperature of the preset drying oven, the temperature of the hot air to be supplied into the drying furnace hot air source so that the target temperature Heating control means for controlling is provided, on the other hand, a furnace temperature sensor for measuring the temperature in the drying furnace is provided in the drying furnace, and the furnace temperature measured by the furnace temperature sensor and a preset furnace setting Supply into the drying furnace based on the temperature difference
Air volume control means for controlling the supply amount of hot air is characterized in that is provided.

[0039] Thus, according to the drying apparatus according to claim 1 ceramic molding according, outside air is sucked to the air suction duct,
The outside air temperature sensor measures the outside air temperature, and the outside air humidity sensor measures the outside air relative humidity. The target temperature of the hot air to be supplied into the drying furnace is calculated by the calculating means based on the preset wet-bulb temperature in the drying furnace, the measured outside air temperature and the outside air relative humidity.

The heating control means controls the hot air source so that the obtained target temperature of the hot air is reached, the outside air is heated by the hot air source, and the hot air of the target temperature is supplied into the drying furnace through the hot air supply duct. .

Then, the ceramic molded article is dried by the hot air supplied into the drying oven, and the wet-bulb temperature of the hot air supplied into the drying oven is the same as the set wet-bulb temperature in the drying oven. Further, when the hot air is adiabatically cooled by drying, the relative humidity of the hot air rises, but the wet-bulb temperature of the hot air does not change. Therefore, since there is no difference between the temperature of the ceramic molded product and the wet-bulb temperature in the drying furnace, the drying proceeds stably, and the deformation and cracks of the ceramic molded product due to the significant difference in shrinkage accompanying drying are suppressed. It

On the other hand, the hot air supplied to the drying furnace is set at a target temperature based on the set wet-bulb temperature in the drying furnace, the outside air temperature and the outside air relative humidity. Cannot be followed. Therefore, the temperature in the drying oven is measured by the oven temperature sensor to obtain the oven temperature, the difference between the oven temperature and the oven set temperature is obtained, and the air volume control means is controlled based on this difference to control the hot air flow. By controlling the supply amount, the temperature in the drying furnace is kept at the set temperature in the furnace.

A drying device for a ceramic molded article according to claim 1 is
Since it is configured as described above, it has the following advantages. Hot air with a target temperature corresponding to the set wet-bulb temperature in the drying furnace can be supplied, and the ceramic molding can be dried in a state where the wet-bulb temperature of the hot air and the temperature of the ceramic molding match. It is possible to suppress the deformation and cracking of the ceramic molded article due to the difference in shrinkage due to the drying which tends to occur due to the difference between the wet-bulb temperature and the temperature of the ceramic molded article, and it is possible to dry the ideal ceramic molded article.

By controlling the wet-bulb temperature in the drying furnace by controlling the temperature of the hot air and controlling the temperature in the drying furnace by controlling the supply amount of the hot air, ideal drying of the ceramic molded article is realized, and the ceramic molded article is realized. The dry yield can be improved.

Further, the temperature control of the hot air is aimed at controlling the wet-bulb temperature in the drying furnace, and the control of the supply amount of the hot air is aimed at controlling the temperature in the drying furnace. It is possible to control the temperature and supply amount of hot air independently compared to the case of controlling the temperature of hot air and the amount of steam mixed to control the temperature, and to optimize the atmosphere in the drying oven. This is extremely easy, and an operator of a drying furnace or the like having no special knowledge about drying can easily change the control of drying.

According to a second aspect of the present invention, there is provided an apparatus for drying a ceramic molded article,
A drying furnace for housing the wet-molded ceramic moldings is provided, a hot air supply source is provided in the hot air supply duct connected to the drying furnace, an outside air suction duct is connected to the hot air generation source, and an exhaust duct is provided in the drying furnace. In the connected kiln molding drying device, a hot air temperature sensor that measures the temperature of hot air and a hot air humidity sensor that measures the relative humidity of hot air are installed in the hot air supply duct, and the hot air temperature and hot air measured by the hot air temperature sensor Based on the hot air relative humidity measured by the humidity sensor, a calculating means for obtaining a target temperature of hot air corresponding to a preset wet-bulb temperature in the drying oven, and the temperature of the hot air supplied to the drying oven is the target temperature. Heating control means for controlling the hot air source is provided so that the drying furnace is provided with an in-furnace temperature sensor for measuring the temperature in the drying furnace, and the heating temperature is measured by the in-furnace temperature sensor. Air volume control means for controlling the supply amount of hot air was based on the difference between the furnace temperature and a preset furnace set temperature is characterized in that is provided.

According to the drying apparatus for the ceramic molded article of the second aspect , the outside air is sucked into the outside air suction duct, and the outside air is heated by the hot air source and fed into the hot air supply duct. The hot air temperature sensor measures the hot air temperature and the hot air humidity sensor measures the hot air relative humidity.

Based on the preset wet-bulb temperature in the furnace, the measured hot air temperature and the hot air relative humidity, the target temperature of the hot air to be supplied into the drying furnace is calculated by the calculating means. The heating control means controls the hot air source so that the obtained target temperature of the hot air is reached, the outside air is heated by the hot air source, and the hot air of the target temperature is supplied into the drying furnace through the hot air supply duct.

The ceramic molding is dried by the supplied hot air, and the wet-bulb temperature of the hot air supplied into the drying furnace is the same as the set wet-bulb temperature in the drying furnace. When the hot air is adiabatically cooled by drying, the relative humidity of the hot air rises, but the wet-bulb temperature of the hot air does not change. Therefore, since there is no difference between the temperature of the ceramic molding and the wet-bulb temperature in the drying furnace, the drying proceeds stably, and the deformation or cracking of the ceramic molding due to the significant difference in shrinkage accompanying drying is suppressed. It

On the other hand, the hot air supplied to the drying oven is set at a target temperature based on the set wet-bulb temperature in the drying oven, the hot air temperature, and the relative humidity of the hot air. Cannot be followed. Therefore, the temperature in the drying oven is measured by the oven temperature sensor to obtain the oven temperature, the difference between the oven temperature and the oven set temperature is obtained, and the air volume control means is controlled based on this difference to control the hot air flow. By controlling the supply amount, the temperature inside the drying furnace is kept at the set temperature inside the furnace.

The drying apparatus for the ceramic molded article according to claim 2 is:
Since it is comprised as mentioned above, in addition to the effect of the drying apparatus of the ceramic molding of Claim 1 , it has the following advantages. Since the hot air temperature sensor and the hot air humidity sensor are provided in the hot air supply duct, the target temperature of the hot air supplied into the drying furnace can be maintained more stably. If these sensors are provided near the drying oven of the hot air supply duct, the accuracy of the target temperature of the hot air can be further improved.

According to a third aspect of the present invention, there is provided a device for drying a ceramic molded article,
In the drying apparatus for the ceramic molded article according to claim 1 or 2 , the air flow control means has a blower fan provided in the outside air suction duct, and the difference between the furnace temperature measured by the furnace temperature sensor and the furnace preset temperature. And a blower controller that controls the blower fan based on the above.

According to the ceramic molded article drying apparatus of the third aspect, the blower controller controls the blower fan on the basis of the difference between the furnace temperature measured by the furnace temperature sensor and the furnace preset temperature. Therefore, the supply amount of hot air corresponding to the set temperature of the drying furnace is accurately controlled.

[0054] Further, the drying apparatus according to claim 3 ceramic moldings according, since the configuration of the above, in addition to the effect of drying apparatus according to claim 1 or 2 ceramic molded product described exhibit, sucking the outside air by the blowing fan And because hot air is supplied into the drying oven,
Since it is not necessary to install a damper in the outside air suction duct or hot air supply duct, the structure of the device is simple, and since the air volume control means consists of a blower fan and a blower controller, the blower controller is controlled by the blower controller. Therefore, hot air corresponding to the set temperature in the furnace can be accurately supplied, and the temperature of the drying furnace can be easily and accurately controlled.

According to a fourth aspect of the present invention, there is provided a drying device for a ceramic molded article,
The drying apparatus according to claim 1 or 2 Ceramic moldings according, air volume control means comprises a hot air damper provided in the hot air supply duct, the furnace temperature and furnace setting temperature measured by the furnace temperature sensor The opening / closing controller opens / closes the hot air damper based on the difference between the hot air damper and a circulation duct that circulates a part of the hot air branched by the hot air damper to the outside air suction duct and a blower fan for the outside air suction duct. It is characterized by being provided.

[0056] supplying According to the drying apparatus according to claim 4 ceramic molded product according the Aspirate to Rutotomoni hot outside air by the blowing fan into the drying furnace. A hot air damper is provided in the hot air supply duct to which hot air is supplied, and the opening / closing controller opens and closes the hot air damper based on the difference between the furnace temperature measured by the furnace temperature sensor and the furnace preset temperature. Since the air blowing is controlled by, the supply amount of hot air corresponding to the set temperature of the drying furnace is accurately controlled. Moreover, a part of the hot air branched by the hot air damper is circulated to the outside air suction duct through the circulation duct.

According to a fourth aspect of the present invention, there is provided a drying device for a ceramic molded article,
Due to the above-mentioned configuration, in addition to the effect of the drying device for the ceramic molded article according to claim 1 or 2 , a blower for sucking outside air and supplying hot air into the drying furnace is provided, but a damper for hot air The opening and closing of the hot air controls the amount of hot air supplied to the drying furnace, and part of the hot air branched by the hot air damper is circulated to the outside air suction duct through the circulation duct, so the hot air must be reused. Can
It is possible to reduce the amount of heating to the outside air by the hot air source to save energy in the drying device.

Further, since the air volume control means comprises the hot air damper and the opening / closing controller, the opening / closing of the hot air damper is controlled by the opening / closing controller, so that the hot air corresponding to the set temperature in the furnace can be accurately measured. In addition to being able to supply, the temperature inside the drying furnace can be controlled easily and accurately, and the blower fan can be operated while maintaining a constant rotation speed.

[0059]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a ceramic molding drying apparatus according to the first embodiment, FIG. 2 is a schematic view of a ceramic molding drying apparatus according to the second embodiment, and FIG. 3 is a third embodiment. A schematic diagram of a drying device for such a ceramic molding,
FIG. 4 is an explanatory diagram showing the relationship between the wet bulb temperature and temperature control, and FIG.
Is a graph showing the drying characteristics of the ceramic molded article drying apparatus according to the first embodiment, and FIG. 6 is a schematic view of the conventional ceramic molded article drying apparatus.

A ceramic molded article drying apparatus according to the first embodiment of the present invention will be described. (Overall Structure) As shown in FIG. 1, a batch-type drying oven 10 for accommodating the ceramic moldings is provided, and although not shown, the air in the drying oven 10 is agitated inside the drying oven 10. A stirring fan is provided to make the atmosphere in the drying furnace 10 more uniform.

One end of the hot air supply duct 12 is connected to the drying oven 10, the hot air generation source 14 is connected to the other end of the hot air supply duct 12, and the outside air suction duct 18 is connected to the hot air generation source 14.
Is connected to one end and the other end of the outside air suction duct 18 is open.

The hot air supply duct 12 is for supplying hot air (outside air heated by the hot air source 14) into the drying furnace 10. The outside air suction duct 18 is a source of hot air for the outside air 1
4, the hot air source 14 is for heating the outside air, and a burner is used as a concrete means.

The outside air suction duct 18 is provided with a blower fan 16. The blower fan 16 sucks the outside air into the outside air suction duct 18 and sends the outside air sucked into the outside air suction duct 18 to the hot air source 14. In addition, it has a function of supplying hot air into the drying furnace 10.
Constitutes a part of the air volume control means 32 for controlling the supply amount of hot air described later.

At the upstream side of the outside air suction duct 18 provided with the blower fan 16, an outside air temperature sensor 20 for measuring the dry-bulb temperature of the outside air (hereinafter, simply referred to as outside air temperature) and the relative humidity of the outside air (hereinafter, referred to as An outside air humidity sensor 22 is provided for measuring the outside air relative humidity).

[0065] the outside air temperature sensor 20 and the outside Kishime temperature sensor 2
2 is connected to the calculating means 24 so that the measured outside air temperature and the measured outside air relative humidity can be transmitted to the calculating means 24 provided separately. If an outside air damper is provided further upstream of both sensors 20 and 22 provided in the outside air suction duct 18, the amount of outside air suctioned can be controlled by opening and closing the outside air damper.

(Calculating Means) The calculating means 24 is a target dry-bulb temperature of hot air which is optimum for drying (hereinafter, simply referred to as target temperature).
In addition to the above, it has a function of controlling the heating control means 26 described later based on the target temperature. Then, the calculation means 24 stores the data of the set wet-bulb temperature in which the wet-bulb temperature in the drying furnace 10 is preset, and also sets the wet-bulb temperature in the drying furnace 10, the measured outside air temperature and the outside air. A program for determining the target temperature of hot air based on relative humidity is stored.

The program for obtaining the target temperature of the hot air by the calculating means 24 comprises a procedure for obtaining the following elements based on the humidity chart shown in FIG. Relative humidity 10 corresponding to the set wet bulb temperature in the drying oven 10
Adiabatic cooling line at 0%. Absolute humidity (kg / kg) at measured outside air temperature and outside air relative humidity. Temperature (target temperature) at the intersection of the adiabatic cooling line at the set wet-bulb temperature in the drying furnace 10 and a relative humidity of 100% and the measured outside air temperature and absolute humidity (kg / kg) at the outside air relative humidity.

On the basis of this humidity chart, the intention to obtain the target temperature from the set wet-bulb temperature in the drying furnace 10, the measured outside air temperature, and the outside air relative humidity is, in particular, the deformation of the ceramic molding during the constant rate drying period and This is to control the wet bulb temperature in the drying furnace 10 by controlling the temperature of hot air in order to suppress cracks.

(Heating control means) The heating control means 26 is connected to the above-mentioned calculation means 24 and also to the hot air source 14 and is based on the target temperature of the hot air obtained by the calculation means 24. This is for controlling the heating of the hot air generating source 14 with respect to the outside air.

Therefore, the hot air source 14 heats the outside air under the control of the heating control means 26, but heats the outside air until the temperature of the hot air obtained by heating the outside air reaches the target temperature. In this embodiment, in order to increase the accuracy of the heating temperature of the outside air by the hot air source 14, the hot air temperature sensor 34 that measures the temperature of the hot air is used as the hot air supply duct 12
The hot air temperature sensor 34 is connected to the heating control means 26.

Therefore, the temperature of the hot air measured by the hot air temperature sensor 34 (hereinafter referred to simply as the hot air temperature) is transmitted to the heating control means 26, and the measured hot air temperature and the target temperature of the hot air are compared, and the result is obtained. Hot air source 14
Therefore, the temperature control of the hot air is extremely accurately performed.

On the other hand, the oven temperature sensor 28 for measuring the temperature in the oven 10 is provided in the oven 10. The in-furnace temperature sensor 28 is connected to the blast controller 30 so that the measured in-furnace temperature (hereinafter, simply referred to as in-furnace temperature) can be transmitted to a separately provided blast controller 30. The blower controller 30 is for controlling the operation of the blower fan 16 provided in the outside air suction duct 18, and the blower controller 30 and the blower fan 16 constitute an air volume control means 32.

The blower controller 30 will be described in detail. Comparison between the in-furnace temperature measured by the in-furnace temperature sensor 28 and a preset temperature in the drying oven 10 (hereinafter, simply referred to as in-furnace preset temperature) Is performed by the blower controller 30 and the temperature inside the furnace is higher than the preset temperature inside the furnace, the blower fan 1
6 reduces the amount of hot air supplied to the drying furnace 10 on the other hand, and on the other hand, when the temperature in the furnace is lower than the preset temperature in the furnace, the blower controller 30 is used to increase the amount of hot air supplied by the blower fan 16. The operation of the blower fan 16 is controlled to maintain the temperature inside the drying furnace 10 at the furnace set temperature.

The purpose of the air volume control means 32 consisting of the air blower fan 16 and the air blow controller 30 is to suppress the deformation and cracks of the ceramic molding during the constant rate drying period, and at the same time, to control the hot air supply rate in the drying furnace. The purpose is to control the temperature.

The preset temperature in the furnace in this embodiment is set so as to increase with time in the constant rate drying period in order to further shorten the drying time of the ceramic molding. The data of the set temperature in the furnace is stored in the blower controller 30.

Further, by setting the set temperature in the furnace so as to increase with time, the water content contained in the ceramic molded article decreases and the strength of the ceramic molded article increases as the temperature rises. It is possible to suppress deformation and cracks due to a significant difference in shrinkage due to.

(Exhaust Duct) An exhaust duct 36 is provided in the drying furnace 10 for discharging the air in the drying furnace 10, and an exhaust damper 38 for adjusting the exhaust amount is provided in the exhaust duct 36. On the other hand, a furnace pressure sensor 40 is installed in the drying furnace 10.
Is provided, and the opening and closing of the exhaust damper 38 is controlled according to the pressure in the drying furnace 10 measured by the in-furnace pressure sensor 40 to exhaust gas.

The drying furnace 1 is controlled by controlling the opening / closing of the exhaust damper 38.
The purpose of adjusting the pressure in 0 is that when the pressure in the drying furnace 10 becomes high, the supply of hot air to the drying furnace 10 is hindered and the inner wall of the drying furnace 10 may be physically damaged. In view of this, it is to prevent the physical damage to the inner wall of the drying furnace 10 as well as to stably supply the hot air into the drying furnace 10.

Next, the control of the drying method will be described together with the control of the drying apparatus for the ceramic molded article according to the first embodiment. Regarding the control of the wet-bulb temperature in the drying oven 10 of this embodiment, the outside air temperature measured by the outside air temperature sensor 20, the outside air relative humidity measured by the outside air humidity sensor 22, and the preset drying oven 10 are set. The target temperature of the hot air is obtained by the calculating means 24 from the set wet-bulb temperature in the inside, and the heating control means 26 is controlled based on the target temperature to control the heating of the outside air by the hot air source 14.

The control of the wet-bulb temperature in the drying furnace 10 by controlling the temperature of the hot air is effective for preventing the deformation and cracks during the drying of the ceramic molding. Since the undried ceramic moldings are moist containing water, the temperature of the ceramic moldings was measured by the wet-bulb temperature of the atmosphere around the ceramic moldings (a damp gauze was attached to the thermometer. Temperature) can be treated almost the same.

Therefore, if the temperature of the ceramic molding during the constant rate drying period and the wet-bulb temperature in the drying furnace 10 during the constant rate drying period can be kept equal after the heating period has passed, the heat of the hot air will change to the moisture content. It is used only for evaporation and can dry ceramic moldings at appropriate drying rates. Therefore, it is possible to prevent deformation and cracks in the ceramic molded product during the constant rate drying period without causing rapid drying of a part of the ceramic molded product or dew condensation on the surface of the ceramic molded product.

In the substantially closed drying oven 10, even when hot air is used for drying the ceramic molding, it is approximately adiabatically cooled, and when the hot air is adiabatically cooled, the wet-bulb temperature of the hot air is obtained in the process of adiabatic cooling. Does not change.

In order to maintain the wet-bulb temperature in the drying furnace 10 at the set wet-bulb temperature, the target temperature of the hot air should be located on the adiabatic cooling line corresponding to the set wet-bulb temperature in the drying furnace 10. And the outside air may be heated so as to reach the obtained target temperature.

Therefore, the heating of the target temperature is performed by the drying furnace 10.
Even if the hot air is supplied to the inside of the drying oven 10 and the hot air is used for drying in the drying oven 10, the wet bulb temperature in the drying oven 10 is maintained at the same as the set wet bulb temperature. Since the temperature of the molded product is the same, the drying of the ceramic molded product proceeds stably during the constant rate drying period.

On the other hand, the temperature control in the drying furnace 10 is performed by controlling the supply amount of hot air. That is, when the temperature in the drying oven 10 is lower than the temperature of the hot air, even if the temperature of the hot air is constant, increasing the supply amount of the hot air to be supplied causes the temperature in the drying oven 10 to increase according to the supply amount. It utilizes the rising phenomenon.

A specific example of controlling the drying of the ceramic molded article in this embodiment was performed based on the following program. The heating period was set to about 2 hours, and the wet bulb temperature in the drying furnace 10 was set to increase from 35 ° C. to 45 ° C. so that the temperature of the ceramic molded product rises from 35 ° C. to 45 ° C. in this period.

Next, the constant rate drying period was set to about 8 hours, the set wet-bulb temperature in this period was set to 45 ° C., and the furnace temperature was set to increase stepwise from 47 ° C. to 68 ° C. The rate-decreasing drying period was set to about 4 hours, and the set wet-bulb temperature during this period was also set to 45 ° C, while the furnace temperature was raised from 68 ° C to 80 ° C, and the holding time was set to about 2 hours at 80 ° C. (See Figure 5).

Since the outside air temperature in this drying was 35 ° C. and the relative humidity of the outside air was 60%, the set wet-bulb temperature in the drying furnace 10 was also 45 ° C.
Therefore, the target temperature of the hot air was 145 ° C. (see FIG. 4).

When the ceramic moldings were dried based on the above settings and conditions, almost no deformation or cracks due to drying occurred in the dried ceramic moldings. That is, the target temperature of hot air corresponding to the set wet-bulb temperature in the drying furnace 10 is obtained from the set wet-bulb temperature in the drying furnace 10, the measured outside air temperature and the outside air relative humidity, and the outside air is heated to the target temperature. However, the hot air obtained by heating the outside air is supplied into the drying furnace 10, and the hot air having the target temperature supplied into the drying furnace 10 does not change the wet-bulb temperature even if it is used for drying, and the set wet-bulb temperature is maintained. By maintaining the temperature, the temperature of the ceramic molded article and the wet-bulb temperature in the drying furnace 10 are kept in agreement with each other, so that a part of the ceramic molded article does not undergo rapid drying or dew condensation on the surface. is there.

Since the control is such that the set wet-bulb temperature in the drying furnace 10 during the constant rate drying period and the temperature of the ceramic molded product are always matched, the set wet-bulb temperature can be freely changed according to the type of the ceramic molded product. Since the target temperature of the hot air is calculated so that the temperature of the ceramic molding matches the set wet-bulb temperature, there is no need to consider the relationship between temperature and relative humidity as in the conventional case.
It became easy to change the control of drying by the 0 operator.

[0091] In addition, is performed by controlling the supply amount of the temperature control hot air drying furnace 10, if wet-bulb temperature be varied the temperature of the drying oven 10 is long as it is maintained at the set wet-bulb temperature The drying time can be freely changed within a certain range, and in this embodiment, the drying time can be shortened to 14 hours.

Further, even if the outside air temperature or the outside air relative humidity fluctuates during drying, the calculation means 24 obtains the target temperature of the hot air so as to correspond to these fluctuations, and the heating control means based on the target temperature. 26 is controlled,
The hot air can be appropriately heated by the hot air source 14.

Next, a drying device for ceramic molded articles according to the second embodiment will be described. In the drying device of this embodiment, the hot air temperature sensor 42 and the hot air humidity sensor 4 are used.
4 is provided in the hot air supply duct 12, and the hot air temperature sensor 4
The temperature of the hot air measured by 2 (hereinafter simply referred to as the hot air temperature) and the relative humidity of the hot air measured by the hot air humidity sensor 44 (hereinafter simply referred to as the hot air relative humidity) are calculated by the calculating means 4
6 is different from that of the previous embodiment in that it is provided so as to be transmitted to No. 6.

Therefore, the hot air temperature is detected by the hot air temperature sensor 4
2 and the hot air relative humidity is measured by the hot air humidity sensor 44. The measured hot air temperature and hot air relative humidity are transmitted to the calculating means 46, and the calculating means 46 obtains the target temperature of the hot air from the hot air temperature, the hot air relative humidity, and the set wet-bulb temperature in the drying furnace 10. Based on the obtained target temperature, the heating control means 26 causes the hot air source 14
To control the heating of the outside air.

In this embodiment, the hot air temperature sensor 42 is provided near the drying oven 10 of the hot air supply duct 12, and the hot air temperature is monitored immediately before the hot air is supplied to the drying oven 10. The heating control of the hot air source 14 by the heating control means 26 can be a more delicate control with respect to the target temperature of the hot air, and therefore the temperature of the hot air supplied into the drying furnace 10 can be controlled more accurately. .

Next, a drying device for ceramic molded articles according to the third embodiment will be described. In the drying device of this embodiment, a hot air damper 50 is provided in the hot air supply duct 12, and an opening / closing controller 52 is provided in place of the air blowing controller 30 in the first embodiment. Open / close controller 5
Reference numeral 2 denotes a furnace temperature sensor 5 so that the furnace temperature measured by the furnace temperature sensor 54 can be transmitted to the switching controller 52.
4 is connected to the hot air damper 50 in order to control the opening and closing of the hot air damper 50.

A circulation duct 56 for circulating a part of the hot air branched by the hot air damper 50 to the outside air suction duct 18 is provided. The circulation duct 56 is provided from the hot air damper 50 to the outside air temperature sensor 20 and the outside air humidity. Sensor 2
2 is connected to the outside air suction duct 18 on the upstream side.

The open / close controller 52 includes a furnace temperature sensor 54.
It is possible to control the opening and closing of the hot-air damper 50 according to the temperature inside the furnace, which is measured by, to control the supply amount of hot air. Therefore, the air volume control means 48 in this embodiment comprises the opening / closing controller 52 and the hot air damper 50. In this embodiment, the blower fan 58 provided in the outside air suction duct 18 is operated at a constant rotation speed, and an air volume control means 48 for controlling the supply amount of hot air based on the temperature inside the furnace is used. It does not constitute.

According to this embodiment, the blower fan 58
The outside air sucked by the outside air suction duct 18 is heated by the hot air source 14. Hot air source 14 at this time
In the heating control by the same as in the first embodiment, the target temperature of the hot air is obtained and calculated by the calculating unit 24 from the set wet-bulb temperature in the drying furnace 10, the measured outside air temperature, and the outside air relative humidity. The outside air is heated by the hot air source 14 so as to reach the target temperature of the hot air, and the hot air source 14 is controlled by the heating control means 26.

On the other hand, the temperature control in the drying furnace 10 is performed by controlling the supply amount of hot air by the air amount control means 48.
The air volume control means 48 includes a hot air damper 50 and an opening / closing controller 5.
Since it is composed of two, the furnace temperature measured by the furnace temperature sensor 54 is transmitted to the opening / closing controller 52, and the opening / closing controller 52 controls opening / closing of the hot air damper 50 according to the furnace temperature. Then, the supply amount of the hot air supplied into the drying furnace 10 is controlled.

Since it is not necessary to supply a part of the hot air branched by the hot air damper 50 into the drying furnace 10, it is recovered to the outside air suction duct 18 through the circulation duct 56. The hot air collected in the outside air suction duct 18 is mixed with the outside air and sent to the hot air generating source 14, and is heated again and reused as the hot air, so that the amount of heat to the outside air by the hot air generating source 14 is reduced and drying is performed. Energy saving of the device can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view of a drying device for ceramic molded articles according to a first embodiment.

FIG. 2 is a schematic view of a drying device for ceramic molded articles according to a second embodiment.

FIG. 3 is a schematic view of a drying device for ceramic molded articles according to a third embodiment.

FIG. 4 is an explanatory diagram showing a relationship between a wet bulb temperature and temperature control.

FIG. 5 is a graph showing the drying characteristics of the ceramic molded article drying apparatus according to the first embodiment.

FIG. 6 is a schematic view of a drying device for a conventional ceramic molded article.

[Explanation of symbols]

10 drying oven 12 Hot air supply duct 14 Hot air source 16 Blower fan 18 Outside air suction duct 20 Outside air temperature sensor 22 Outside air humidity sensor 24 Computing means 26 Heating control means 28 Furnace temperature sensor 30 Blower controller 32 Air volume control means 34 Hot air temperature sensor 36 Exhaust duct 38 Exhaust damper 40 In-furnace pressure sensor 42 Hot air temperature sensor 44 Hot air humidity sensor 46 computing means 48 Air volume control means 50 Hot air damper 52 Open / close controller 54 In-furnace temperature sensor 56 Circulation duct 58 Blower fan

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI F27D 7/06 F27D 7/06 C (58) Fields investigated (Int.Cl. ⁷ , DB name) F26B 25/22 F26B 3 / 04 F26B 9/06 F26B 21/00 F27D 7/06

Claims (4)

(57) [Claims] 1. A dry container for containing a wet-molded ceramic molding.
A hot air supply duct equipped with a drying oven and connected to the drying oven
A hot air source is provided, and an outside air suction duct is installed at the hot air source.
Ceramic moldings that are connected and have an exhaust duct connected to the drying furnace
In the drying apparatus, the outside air temperature sensor for measuring the outside air temperature and the ambient relative humidity
An outside air humidity sensor for measuring
The outside air temperature and outside air humidity measured by the outside air temperature sensor
Preset by the relative humidity of the outside air measured by the sensor.
Temperature of hot air corresponding to the set wet-bulb temperature in a dry oven
Is provided so that the temperature of the hot air supplied into the drying furnace reaches the target temperature.
The heating control means for controlling the hot air source is installed in the drying oven , while the oven temperature sensor for measuring the temperature in the drying oven is installed in the drying oven.
Sensor is installed, and the temperature in the furnace measured by the temperature sensor in the furnace is set in advance.
Heat supplied to the drying oven based on the difference in the set temperature in the oven
The provision of air volume control means for controlling the air supply volume
Characteristic ceramic molding drying equipment. 2. A dry material containing a wet-molded ceramic molding.
A hot air supply duct equipped with a drying oven and connected to the drying oven
A hot air source is provided, and an outside air suction duct is installed at the hot air source.
Ceramic moldings that are connected and have an exhaust duct connected to the drying furnace
In the drying apparatus, a hot air temperature sensor and the hot air of relative humidity to measure the temperature of hot air
A hot air humidity sensor is installed in the hot air supply duct to measure
Is, hot air temperature measured by the hot air temperature sensor and a hot air humidity Se
Preset by hot air relative humidity measured by the sensor
Target temperature of hot air corresponding to the set wet-bulb temperature in the drying oven
And the temperature of the hot air supplied to the drying furnace to the target temperature
The heating control means for controlling the hot air source is installed in the drying oven , while the oven temperature sensor for measuring the temperature in the drying oven is installed in the drying oven.
Sensor is installed, and the temperature in the furnace measured by the temperature sensor in the furnace is set in advance.
The hot air supply rate is controlled based on the difference in the set temperature in the furnace .
Ceramic molding characterized by the provision of air flow control means
Equipment for drying things. 3. An air volume control means is provided in an outside air suction duct.
Furnace measured by built-in blower fan and furnace temperature sensor
Controls the blower fan based on the difference between the internal temperature and the set temperature in the furnace
2. A blower controller for controlling
Or the drying device for the ceramic molded article according to 2 . 4. An air volume control means is provided in the hot air supply duct.
Measured by the hot air damper and the furnace temperature sensor.
Based on the difference between the furnace temperature and the preset temperature
An open / close controller that opens and closes the heater, and part of the hot air branched by the hot air damper is sucked into the outside air.
There is a circulation duct for circulation to the
A blower fan is provided in the suction duct.
The apparatus for drying a ceramic molding according to claim 1 or 2.