JPH08299698A - Vacuum drying method - Google Patents

Abstract

PURPOSE: To provide a vacuum drying method capable of forcibly drying leather products processed with water washing and spin-drying in a short time without shrinking or hardening them. CONSTITUTION: Leather clothes 3 are stored in the storage space 10 of a chamber 1. The heating procedure heating the storage space 10 to the temperature Tc by driving a far infrared panel heater 5, feeding the dust-removed, dehumidified, heated control air from an air feed duct 6, and driving a stirring fan 7, the steaming procedure stopping the feed of the control air and controlling the far infrared panel heater 5 to keep the storage space 10 between the temperature Tc and the upper limit temperature Tm, and the decompressing/exhausting procedure discharging the air in the storage space 10 with a vacuum pump 4 are repeatedly conducted. The upper limit temperature Tm is determined to the range not shrinking or hardening the leather clothes 3, and the steam filled in the storage space 10 in the steaming procedure of each cycle is discharged to the outside in the decompressing/exhausting procedure in the oversaturated state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum drying method, not only for drying ordinary laundry but also for washing leather products with water.
The present invention relates to a drying method which is applied to a drying step after dehydration treatment and which is capable of dramatically shortening a drying time and capable of performing a natural finish without causing shrinkage or curing of a leather product after drying.

[0002]

2. Description of the Related Art Conventionally, various washing / drying methods have been adopted in the cleaning industry, but when roughly classified, there are cases of washing with normal water and cases of using Park Roll ethylene or petroleum-based solvent, Regarding drying, there are cases of hot air drying and cases of natural drying.
Then, in the cleaning factory, the requested clothing is classified according to the attributes such as the fiber material, the form, and the sewing mode,
Based on empirical judgment, each classified clothing item is sent to the most suitable treatment step among the various washing and drying steps.

By the way, in recent years, leather-made winter clothes and fashion clothes have come to be widely used by taking advantage of the characteristics of leather (flexibility, toughness, durability, breathability, heat retention, comfortable feel, etc.). However, a lot of leather clothes tend to be concentrated on cleaning before and after the season when the clothes are used, but at the cleaning factory, special treatment is required for the method of washing and drying the leather clothes for the following reasons. Is forced.

There are various kinds of leather raw materials for leather clothing, such as mammals such as cows, pigs and sheep, reptiles such as crocodile and snakes, fish such as sharks, but they are generally weak to heat and have high heat. Shrinks and hardens when exposed to heat (for example, the heat distortion temperature of cow and pig skin is 5
The temperature of the shark skin is as low as 9 ° C and 49 ° C, and the contraction rate is very large, 5 to 25%, although it varies depending on the site. ), Dyeing fastness is weak, it is easy to lose color by washing, the cortex is not constant, and even the integrated leather has different tissues depending on the site, so uniform drying is difficult,
Leather consists of an epidermis, a silver surface layer, and a net-like layer, but it has the peculiarity that water tends to remain in the silver surface layer and the net-like layer, causing mold to develop. . Therefore, in the washing process of leather clothing, water that has less effect of decoloring action is used when it is necessary to consider the problem of dyeing fastness, and when the drying temperature is considered, the volatilization temperature is low. Ethylene, petroleum-based solvents, etc. are used, and in the drying process, since the leather clothing is extremely delicate to heat, the usual hot air drying method cannot be adopted, and most of them are naturally dried.

[0005]

As is apparent from the above, in the washing and drying of leather clothing, the general methods of washing with water and natural drying give the safest and best finished results for the characteristics of the product. It can be said that it is a method. In addition, when petroleum-based solvents are used in the washing process, the vapor must always be liquefied and recovered by a heat exchanger for cooling, etc. in order to generate environmental pollution. Washing with water is preferable.

By the way, in the case of washing with water and natural drying, the leather clothes after washing with water are dehydrated to some extent, suspended in a room, and dried under natural temperature, humidity, and air volume conditions. Such problems have been pointed out. (1) Room temperature, humidity and atmospheric pressure are not always constant,
The circulation of air is indispensable to reduce the humidity in the room in order to improve the drying efficiency, but when forced ventilation is used, the evaporation of water is promoted only on the surface of the leather, and the relationship with the internal stratification in the wet state is promoted. However, the product is not balanced and shrinks or hardens (curves) after drying. (2) In case of natural drying, it greatly depends on the season and weather, so normally, after a few days have passed, it is empirically judged whether or not the drying is completed by checking the dryness by the feel of the hand. However, there are various kinds of leather products, and the empirical judgment is not always accurate, and if moisture remains in the net-like layer or the like, mold will be generated later. (3) As mentioned above, leather clothing tends to be concentrated for cleaning during the season in which it is used, and since the progress of natural drying is extremely slow, it is a dedicated space for drying only leather clothing. Must be secured large, and the equipment area in the cleaning plant becomes very large, resulting in poor space utilization efficiency.

Therefore, the present invention is to wash leather products with water.
We provide a vacuum drying method that can drastically shorten the drying time after dehydration treatment and obtain a natural finish without causing shrinkage or curing of the dried product, thereby resulting in the above-mentioned problems. It was created for the purpose of solving the problem.

[0008]

According to the present invention, in a vacuum drying method, an infrared heater having a radiation surface directed to the accommodation portion side of the drying object, and an air inside a chamber having a space for accommodating the drying object. A stirring fan, a management air supply unit,
A temperature sensor for detecting the temperature of the accommodation space is equipped, a valve for switching the accommodation space and the outside of the chamber between a vented state and a non-vented state, and an air for supplying temperature and humidity controlled air to the control air supply section. A valve is provided after a supply unit and a decompression unit for forcibly discharging the air in the accommodation space to the outside to decompress the atmospheric pressure of the accommodation space, accommodating an object to be dried in the accommodation space and sealing the chamber, A heating step of heating the infrared heater, the air agitating fan, and the air supply means to a ventilation state to heat the accommodation space to a predetermined temperature below the upper limit temperature determined based on the attribute of the object to be dried, When the temperature sensor detects the predetermined temperature, the valve is switched to the non-ventilated state, the driving of the air supply means is stopped, and the infrared ray is transmitted. And procedures steaming for a predetermined time is held at a temperature range of less than the upper limit temperature of the housing space and controls the over data, after a predetermined time has elapsed in the steaming procedure,
The driving of the infrared heater is stopped, the decompression means is activated, and the decompression / exhaust procedure of exhausting the air in the accommodation space to the outside is executed as the first cycle, and thereafter, the valve is kept in the non-ventilated state. The present invention relates to a vacuum drying method characterized in that a cycle including the same procedure as described above is repeatedly executed.

[0009]

In the vacuum drying method of the present invention, the drying target contained in the chamber is repeatedly heated, then steamed, and then decompressed and exhausted, to gradually remove moisture from the target. go. In the heating procedure, heating is performed by supplying management air to the accommodation space of the chamber and radiant heat of infrared rays, and stirring is performed by a stirring fan in order to make the temperature and humidity of the whole uniform. The moisture of the object to be dried gradually starts to evaporate from this stage, and this heating is performed until the accommodation space reaches a predetermined temperature below the upper limit temperature determined based on the attribute of the object to be dried. Air whose temperature and humidity are controlled is supplied from the initial state (first cycle) or the low temperature state after decompression / exhaust (second cycle or later) only by radiant heat of infrared rays. This is because the amount of vapor evaporated from the object to be dried can be increased by decreasing the relative humidity. In the second and subsequent cycles, the decompressed accommodation space is filled with management air.

In the steaming procedure, the temperature of the storage space is determined by the attribute of the object to be dried by controlling the radiation of infrared rays while continuing the stirring while stopping the supply of the control air and keeping the valve non-ventilated. Hold within the following range for a certain period of time. Evaporation of moisture from the object to be dried continues from the above heating procedure, but the temperature of the object to be dried differs between the surface and the inside and between the surface layer and the inner layer, and if the heating procedure is performed above the upper limit temperature, the surface is If only the surface and the surface layer are over-dried and the object to be dried is delicate to heat, irreversible shrinkage / curing will occur. In this steaming procedure, the temperature of the storage space is kept in a constant range close to the upper limit temperature to maintain a steaming state, and the efficiency of heat transfer is increased by high-humidity air to make the temperature of the entire drying object uniform and the surface layer and inner layer. Promotes the transfer of moisture to and from. Therefore, it is possible to promote uniform evaporation of moisture from the entire object to be dried while preventing partial overdrying. Further, in this steaming procedure, since the valve is in a non-ventilated state, the pressure in the storage space increases, the relative humidity decreases, and the evaporation efficiency of the liquid component increases.

In the depressurization / exhaust procedure, the infrared radiation is stopped and the air in the storage space is forcibly discharged to the outside. Are released to the outside.
The air agitating fan loses its practicability when the air is depressurized / exhausted, so it may be stopped in this procedure.

[0012]

Embodiments of the vacuum drying method of the present invention will be described in detail below with reference to the drawings. In this example, the case where the leather clothes are washed with water and dehydrated and then forcedly dried will be described. First, FIG. 1 shows a sectional view of a chamber and a temperature / pressure control system of a housing space in a vacuum drying apparatus to which the method of the present invention is applied, and FIGS. 2 and 3 respectively show a front view of the chamber and FIG. 3 is a sectional view taken along line YY in FIG. In each figure, 1 is a chamber, 2 is a lot of leather clothing
(Object to be dried) 3 is a trolley configured to be suspended on a horizontal rod 2a using a hanger, and the trolley 2 is a chamber 1
It can be slid on the guide table 4 provided on the lower side of the chamber, and can be taken in and out with the front door 1a of the chamber 1 opened. A window 1b sealed with a transparent resin plate is formed in the front door 1a so that the inside of the chamber 1 can be confirmed from the outside. And, inside the both side walls of the chamber 1, a far-infrared panel heater 5 of a steam heating system is installed with its radiation surface facing inward, and a large number of nozzles are formed on the lower side for air supply. Ducts 6 are laid horizontally along both side walls, and stirring fans 7 are installed on both sides of a guide table 4 corresponding to the lower side thereof. In FIG. 1, 8 is a temperature sensor and 9 is a humidity sensor.
11 is a pressure meter,
When the internal pressure of the storage space 10 becomes abnormally high or low, a check valve (not shown) is automatically operated to return the pressure to the allowable pressure.

On the wall of the chamber 1, steam pipes 21a and 21b connected to the far infrared panel heater 5, an air pipe 22 connected to the air supply duct 6, and a decompression / exhaust air pipe. 23 and an air pipe 24 for adjusting exhaust air are respectively provided at appropriate places, and the pipes 21a, 22, 23, 24 are connected to solenoid valves 31, 32, 33, 34, respectively. Note that, in FIG. 1, for convenience, it is expressed as being provided so as to penetrate through the wall portion on the back surface of the chamber 1, but each pipe 21
The a, 21b, 22, 23, and 24 are pierced at optimal positions in consideration of piping and exhaust efficiency problems. In addition, each solenoid valve 31, 32, 33, 34
The supply system and the discharge system via the are configured as follows. Regarding the supply / exhaust system related to the far infrared panel heater 5, steam from a steam supply source (not shown) is a solenoid valve.
It is input to the far infrared panel heater 5 from 31 through the steam pipe 21a, and the steam passing through the far infrared panel heater 5 is discharged to the drain side through the steam pipe 21b. Regarding the control air supply system, the supplied air is sent to the dehumidifier 42 via the dust filter 41, and the line heater
After heating to the specified temperature with 43, from the solenoid valve 32 to the air pipe
It is sent to the air supply duct 6 via 22. Note that steam is also used as a heating source of the line heater 43, the steam is sent to the radiator portion of the line heater 43 via the solenoid valve 43a, and the used steam is discharged to the drain side. Regarding the decompression / exhaust system, the electromagnetic valve 33 connected to the air pipe 23 is connected to the vacuum pump 44, and the air sucked by the vacuum pump 44 is only exhausted to the drain side. Regarding the adjusted exhaust system, the air in the accommodation space 10 is only exhausted to the drain side via the electromagnetic valve 34 connected to the air pipe 24.

On the other hand, the temperature / pressure control system is the controller 5
1, the controller 51 refers to the detection signals of the temperature sensor 8 and the humidity sensor 9 and the count value of the built-in timer, and each solenoid valve 31, 32, 33 based on the program stored in advance. Open / close control of 34, 43a.

Next, the operation state of the vacuum drying apparatus of the present embodiment having the above-mentioned structure will be described with reference to the operation flow chart shown in FIG. 4 and the temperature change graph of the accommodation space 10 shown in FIG.
The operation timing of each system will be described with reference to the corresponding diagrams. First, when the leather clothes 3 that have been washed with water and subjected to a predetermined dehydration treatment are carried in, the front door 1a of the chamber 1 is opened and the dolly 2 is pulled out, and the dolly with the leather clothes 3 hung on the hangers. Hang it on the horizontal rod 2a of 2 and place the trolley 2 on the chamber 1
Return it inside and close the front door 1a. Then, after selecting and inputting a program to the controller 51 in consideration of the attributes such as the type and shape of the leather of the leather garment 3, the number thereof, the water content weight, etc., an instruction to start the drying is given.

When there is the above-mentioned start instruction, the controller 51
First, the solenoid valve 34 is set to open to make the accommodation space 10 and the outside ventilated, and in that state the solenoid valve 32 and the solenoid valve 31 are set to open and the stirring fan 7 is started (S1 to S4). Thereby, the dust, dehumidified, and heated air in the management air supply system is supplied to the accommodation space 10 through the nozzle of the air supply duct 6, and the far infrared panel heater 5 is aerated with steam to accommodate the accommodation space 10. Far infrared rays are radiated inside,
The air in the accommodation space 10 rises while being stirred.

Therefore, the moistened leather garment 3 is supplied with a quantity of heat from the heated control air and is heated by the radiant heat of far infrared rays to evaporate the water content, but the controller 51 stores it by the output of the temperature sensor 8. The temperature of the space 10 is monitored, and the heating procedure is completed when the temperature reaches the predetermined temperature Tc preset by the selected program, and the solenoid valve 34 and the solenoid valve 32 are set to be closed to store the storage space 10 in the storage space 10. It completely shuts off the outside air and also stops the supply of management air (S
5 ~ S7). In this case, the upper limit temperature Tm at which the leather does not shrink or harden during drying is empirically known depending on the attributes of the leather garment, but the predetermined temperature Tc is a lower temperature and the upper limit temperature Tm The temperature value is set so that the temperature can be controlled within the range that does not exceed the limit. Specifically, in the case of leather, the above-mentioned upper limit temperature Tm is generally 35 ° C to 60 ° C, but for example, the Tm of the leather of the leather clothing 3 in this embodiment is 55 ° C and the temperature control is ±. Tc is set to 50 ° C if possible in the 5 ° C range.

Next, when the heating procedure is completed and the solenoid valves 34 and 32 are set to be closed, the controller 51 turns on the temperature sensor.
The electromagnetic valve 31 is controlled to open / close while referring to the temperature detected from 8, and the amount of radiant heat from the far infrared panel heater 5 is controlled to keep the temperature in the housing space 10 for a certain period of time Ct between Tm and Tc. Keep (S8). That is, the steaming procedure is executed for a certain time Ct. The effectiveness of this steaming procedure can be explained as follows. Although the temperature is raised to Tc in the above heating procedure, even if the heating air is stirred by the stirring fan 7, the outside and inside of the leather clothing 3 and the surface layer and the inner layer of the leather having different radiation conditions of far infrared rays are different. Moreover, a temperature difference occurs between the sewn portion and the non-sewn portion having different water contents, and the degree of progress of water vaporization is different in each portion and locally.
In this procedure, while maintaining the temperature in the closed accommodation space 10 in the above range, the heat transfer efficiency is increased by the stirring air containing a large amount of steam with further evaporation of water,
The temperature of the entire leather garment (3) is raised uniformly while preventing partial or local overdrying, thereby promoting evaporation of water.
In addition, as a side effect, since the accommodation space 10 is sealed, the internal pressure rises and the relative humidity decreases, and in that sense, evaporation of water is also promoted. The running time Ct of the steaming procedure is empirically determined in consideration of the attributes of the leather clothing 3 and the initial water content of the leather clothing 3 and the number of times the cycle is performed, and the control data is used as the control data in the program. It is set.

When the above steaming procedure is executed for the time Ct, the controller 51 immediately closes the electromagnetic valve 31 and stops the stirring fan 7, and the humidity sensor 9 causes the humidity Hu in the accommodation space 10 at that stage. Solenoid valve 3 after detecting
By setting 3 to open, the storage space 10 is
The air inside is exhausted and the inside of the space 10 is depressurized (S
9-S13). At this time, the storage space 10
The inside is in a high humidity state, the temperature is lowered by the attenuation of the infrared radiation amount based on the closing setting of the solenoid valve 31, and the solenoid valve 33
When the atmospheric pressure decreases due to the opening setting, the saturated vapor pressure state is changed all at once, and the vapor contained in the air in the accommodation space 10 is condensed into mist and discharged to the outside. In addition, the guideline for the completion of exhaust at this time is managed by the temperature detected by the temperature sensor 8, and the storage space 10 is generated by discharging the high-humidity air in the heating state in the steaming procedure.
Temperature gradually decreases, and when the temperature reaches a predetermined control temperature To, the depressurization / exhaust procedure is completed (S13, S14). In this depressurization / evacuation procedure, although it depends on the volume of the accommodation space 10 and the execution time of the procedure, for example, even if the volume of the accommodation space 10 is 5 m ³ and the execution time is about 9 minutes, the decompression in the accommodation space 10 is performed. About 72 degrees
It is sufficient to make a low vacuum state of about 0 to 730 torr, and most of the condensed water in the storage space 10 can be discharged.

After the completion of the first cycle, the controller 51 repeatedly executes the heating procedure, the steaming procedure, and the decompression / exhaust procedure (S16 → S2 to S16). However, in the second and subsequent cycles, the operation is performed with the solenoid valve 34 kept closed, and step S6 is unnecessary. That is, when the depressurization / exhaust procedure of each cycle is completed, the inside of the accommodation space 10 is in a low vacuum state, but if the solenoid valve 32 is set to open at the start of the next cycle, dust is removed from the control air supply system. -The dehumidified and heated air is automatically sucked and supplied into the accommodation space 10 through the nozzle of the air supply duct 6 to be filled.

The water content of the leather garment 3 is naturally reduced every cycle because water contained in the leather garment 3 is removed by the same action even in the execution stage of each procedure after the second cycle. Then, the humidity data Hu in the accommodation space 10 detected in step S12 before the depressurization / exhaust procedure is gradually decreased, but when a certain number of cycles are executed, the leather clothing 3 The humidity becomes equal to or lower than the humidity threshold value Ha which is estimated to be completed. Therefore, in this embodiment, the controller 51 compares the humidity data Hu obtained in step S12 with the temperature threshold data Ha for each cycle,
When the depressurization / exhaust procedure of the cycle in which Ha ≧ Hu is completed, the repetition is stopped, the solenoid valve 32 is set to open, and the above-mentioned control air is introduced into the accommodating space 10 in the depressurized state, and the internal pressure is increased. Return to the same level as outside air and finish the drying process (S16
→ S17). It should be noted that the control air to be finally supplied does not have to be the heated air as in the heating procedure, and the controller 51 closes the solenoid valve 43a to make the air close to the room temperature level and then supplies the air into the accommodation space 10. Yes (S1
7).

As described above, the vacuum drying apparatus according to the present embodiment is configured to uniformly dry the leather clothing 3 under the condition that neither shrinkage nor hardening occurs to obtain a natural finish. Considering the water content and thickness of the garment 3, the sewing mode, and the properties of the leather with respect to the temperature when the water content is high and when the drying progresses, it is not only controlled by uniform Tm and Tc, but also within each cycle. It may be more appropriate to change the time required for each cycle, the maximum temperature in each cycle, etc. according to the time ratio of each procedure and the progress of drying.

Specifically, it is desirable that the following control be performed according to various conditions of the leather garment 3 based on conventional experience and experiments relating to the drying of the leather garment 3. (1) The control shown in the graph of FIG. 5 is applied when the leather garment 3 is thick and has a large initial water content. In this case, the time zone of the heating procedure and the steaming procedure is set to be relatively longer than the time zone of the decompression / exhaust procedure, and in particular, the heat is deeply permeated into the leather clothing 3 in the steaming procedure,
By removing more water in each cycle, the total drying time is shortened. (2) In the control shown in FIG. 6, when the initial moisture content of the leather garment 3 is not so large, but the shape and sewing are complicated, and heating or steaming for a long time causes contraction or hardening. Applied to. In this case, contrary to the case of Fig. 5, the time zone of the heating procedure and the steaming procedure is set relatively shorter than the time zone of the decompression / exhaust procedure to minimize the influence on the leather material in the heated state. The decompression / exhaust procedure is performed slowly over a long period of time to ensure dehumidification efficiency. (3) The control shown in FIG. 7 (A) is applied to the case where the leather clothing 3 has a large initial water content and the leather has a delicate property to heat all the time. In this case, the time required for each cycle is gradually shortened in accordance with the number of repetitions, and in the first half cycle, heat is surely permeated into the leather clothing 3 to increase the water removal rate, but the drying As the process progresses, the details of the leather are gently dried while reducing the effect of the leather material in the heated state. (4) In the control shown in FIG. 7 (B), although the leather garment 3 is thin and the initial water content is not so large, when the leather garment 3 has a complicated structure or is partially delicate, It is applied when leather that is susceptible to heat when it contains water is used. In this case, contrary to the case of FIG. 7 (A), the time required for each cycle is gradually lengthened in accordance with the number of repetitions, and in the first half cycle, water is gradually removed from the surface to remove It promotes the movement of water, and when the drying progresses to a certain degree, the whole is dried uniformly. (5) The control shown in FIG. 8 (A) is applied when the leather of the leather garment 3 is not so delicate to heat when the water content is high, but becomes delicate when the drying progresses. It In this case, Tm and Tc are gradually decreased in accordance with the number of times the cycle is repeated, and in the first half cycle, heat is surely penetrated into the leather garment 3 to increase the water removal rate and the drying progresses. At this stage, heating and steaming are performed at a low temperature to achieve a natural finish without shrinkage or hardening of the leather garment 3 while shortening the overall drying time. (6) The control shown in FIG. 8 (B) is applied to the case where the leather of the leather garment 3 is delicate to heat when the water content is high and is not so delicate when the drying progresses. . In this case, contrary to the case of FIG. 8 (A), Tm and Tc are gradually increased in accordance with the number of times the cycle is repeated, and in the first half cycle, heating and steaming are performed at a low temperature to gradually increase the temperature. In order to reduce the total drying time, heat is surely penetrated to the inside of the leather garment 3 at the stage of the progress of drying so that the influence of heating does not occur. (7) The control shown in FIG. 9 takes into consideration the temperature at the time of completion of drying of the leather clothing 3 in the control shown in FIG. 8 (A), and in this case, To Is gradually brought close to room temperature Tn so that the leather garment 3 can be immediately taken out of the chamber 1 and packaged without waiting for the reduction of residual heat at the time of finishing. For each of the above controls, a procedure control program corresponding to each specific condition is prepared in the controller 51,
This can be realized by giving an instruction to select one of these programs before the start of the drying operation and causing the controller 51 to execute each cycle based on the selected program.

By the way, in any of the controls shown in FIGS. 5 to 9, when a large amount of the leather clothing 3 is to be dried, the leather clothing is subjected to a heating procedure or a steaming procedure.
It is difficult to control the degree of evaporation of water from 3 accurately, and the accommodation space 10 may be oversaturated. Then, in such a supersaturated state, the air of high humidity gives an excessive amount of heat to the leather garment 3 as a heat transfer medium, and the heat-sensitive leather garment 3 shrinks or hardens.
Therefore, when an unexpected oversaturation state is confirmed from the detection data of the temperature sensor 8 and the humidity sensor 9, the controller 5
1 interrupts a normal control state, and intermittently sets the solenoid valve 34 to open so that the humidity in the accommodation space 10 is lowered. In this way, by complementing imperfections due to the normal control program, safe drying can always be achieved and stable finish results can be obtained.

In this embodiment, a far infrared panel heater is used.
Although steam is used to heat the air in the 5 and line heater 43, this is because steam is often used for multiple purposes in cleaning plants, and if it is used as a heat source, power consumption can be saved. If there is no steam, those heaters 5 and 43 may be of the electric heating type. In addition, in this example, leather clothing after washing with water
Although the drying method for 3 was explained, it can also be applied to the case of using a petroleum solvent in the washing process, in which case Tm and Tc can be set to a lower temperature than the case of washing with water, and The drying time can be shortened. Further, recently, there is a case where a large stuffed toy product is requested to be cleaned, but the drying method of this embodiment is extremely effective for drying such a product, and conventionally, it has been necessary to naturally dry it for many days. Products can be forced to dry in a matter of hours, and the finished product will also look like leather clothing.
It can be kept in its original natural state as in case 3.

[0026]

The vacuum drying method of the present invention has the following effects due to the above constitution. According to the invention of claim 1, the object to be dried can be forcibly dried extremely efficiently and uniformly at a temperature equal to or lower than the upper limit temperature determined by its attribute, and the drying time can be greatly shortened without impairing the naturalness of the object to be dried. enable. In particular, it is applied to the drying process after washing leather products with water, drying it uniformly in a much shorter time compared to the conventional natural drying method, and it does not shrink or harden, and the silver surface layer or net-like layer It is possible to obtain a finish result in which mold is not generated due to the residual water. The invention of claim 2 enables clear confirmation of the completion state of drying. The invention of claim 3 uses the property that the wavelength band of far infrared rays is easily absorbed by the liquid,
Realize efficient heating by radiant heat. The invention of claim 4 realizes energy saving by utilizing an existing steam supply facility such as a cleaning factory. According to the fifth aspect of the present invention, since the control air is removed after being supplied, the finished product can be prevented from being contaminated. In the invention of claim 6, since the effectiveness of the air agitation fan is lost in the depressurization / exhaust procedure, it is stopped to reduce the power consumption. The invention according to claim 7 is based on the general rule of thumb that the shrinkage and hardening of the leather product occur at temperatures higher than 35 ° C to 60 ° C, and the temperature in the heating / steaming procedure is set to be lower than that. In order to obtain good dry finish results. The invention according to claim 8 to claim 10 is the maximum of the execution time ratio of each procedure within one cycle, the execution time of each cycle, and the steaming procedure, depending on the degree of wetting of the object to be dried, the form, the material characteristics, etc. By varying the temperature, it is possible to obtain even better dry finish results. The invention of claim 11 adaptively prevents the accommodation space from being oversaturated in the heating procedure or the steaming procedure to supply excessive heat to the object to be dried, and always obtains a stable dry finish result. enable.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a chamber of a vacuum drying apparatus according to an embodiment of a vacuum drying method of the present invention and a diagram showing a temperature / pressure control system therein.

FIG. 2 is a front view of a vacuum drying device.

FIG. 3 is a sectional view taken along the line YY in FIG.

FIG. 4 is a flowchart showing an operating state of the vacuum drying device.

FIG. 5 is a graph showing the temperature change of the accommodation space in the vacuum drying device (when the initial water content of the leather clothing is large) and the correspondence diagram of the control air supply, far infrared radiation, the stirring fan, and the operation timing of the vacuum pump. is there.

[FIG. 6] Although the initial moisture content of leather clothing is not so high,
It is a graph which shows the temperature change of the accommodation space based on the control applied when a form and sewing are complicated.

FIG. 7 is a control (A) applied when the leather garment has a large initial water content and the leather has a delicate property to heat all the time, and when the leather garment is thin and has an initial moisture content. Although the amount of water is not so large, the temperature of the storage space based on the control (B) applied when the construction of leather clothing is complicated or partially delicate, or when heat-sensitive leather is used when it contains water. It is a graph which shows change.

FIG. 8: Control applied when the leather of leather clothing is not so delicate to heat when the water content is high, but delicate when the drying progresses (A),
And a graph showing the temperature change of the accommodation space based on the control (B) applied when the leather of the leather clothing is delicate to heat in a state of high water content and is not so delicate in the state of progressing drying. Is.

FIG. 9 is a graph showing a temperature change in the accommodation space based on the control when the temperature at the time of completion of drying the leather clothing is taken into consideration in the control shown in FIG. 8 (A).

[Explanation of symbols]

1 ... Chamber, 1a ... Front door, 1b ... Window, 2 ... Cart, 2a ... Horizontal bar, 3 ... Leather clothing, 4 ... Guide table, 5 ... Far infrared panel heater, 6 ... Air supply duct, 7 ... Agitation Fan, 8 ... Temperature sensor, 9 ... Humidity sensor, 10 ... Accommodation space, 11
… Pressure meters, 21a, 21b… Steam pipes, 22, 23, 24…
Air pipe, 31, 32, 33, 34, 43a ... Solenoid valve, 41 ... Dust filter, 42 ... Dehumidifier, 43 ... Line heater, 44 ... Vacuum pump.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Masahiro Yamaguchi 6-4-5 Higashioi, Shinagawa-ku, Tokyo Inside Sataco Engineering Co., Ltd. (72) Inventor Toshio Nakanishi 3-10-10, Kotobuki-cho, Fuchu-shi, Tokyo No. 20 Tokyo Hall Sale Co., Ltd.

Claims (11)

[Claims] 1. A vacuum drying method, wherein an infrared heater having a radiation surface directed to a storage portion side of the drying target, an air stirring fan, and a management air supply are provided inside a chamber having a storage space for the drying target object. Section and a temperature sensor for detecting the temperature of the accommodation space, a valve for switching the accommodation space and the outside of the chamber between a vented state and a non-vented state, and an air for controlling temperature and humidity in the control air supply section. After the air supply means for supplying and the decompression means for forcibly discharging the air in the accommodation space to the outside to reduce the atmospheric pressure of the accommodation space, the object to be dried is accommodated in the accommodation space and the chamber is closed. , The valve is ventilated to activate the infrared heater, the air stirring fan, and the air supply means to determine the accommodation space based on the attribute of the object to be dried. A heating procedure of heating to a predetermined temperature equal to or lower than an upper limit temperature, and when the temperature sensor detects the predetermined temperature, switches the valve to a non-ventilated state and stops driving of the air supply means to control the infrared heater. And the steaming procedure for holding the temperature of the accommodation space for a certain period of time in the range of the upper limit temperature or less, and after the elapse of a certain period of time in the steaming procedure, the driving of the infrared heater is stopped and the pressure reducing means is activated, and The decompression / exhaust procedure of discharging the air in the accommodation space to the outside is executed as the first cycle, and thereafter, the valve is kept in the non-ventilated state and the cycle of the same procedure as described above is repeatedly executed. Vacuum drying method. 2. The vacuum drying method according to claim 1, wherein a humidity sensor is provided in the accommodation space of the chamber, and the degree of drying of the object to be dried is confirmed from the indicated value of the humidity sensor. 3. The vacuum drying method according to claim 1, wherein the infrared heater is a far infrared radiation panel. 4. The vacuum drying method according to claim 1, 2 or 3, wherein the far infrared heater or / and the air supply means uses steam as a heating source. 5. The air supply means has a dust filter,
The control air from which dust has been removed is supplied,
2, 3 or 4 vacuum drying method. 6. The vacuum drying method according to claim 1, wherein the air agitation fan is stopped in the depressurizing / evacuating procedure. 7. The vacuum drying method according to claim 1, 2, 3, 4, 5 or 6, wherein the upper limit temperature in the steaming procedure is 35 ° C. to 60 ° C. when the object to be dried is a leather product. 8. The ratio of the execution time of each of the heating procedure, the steaming procedure, and the depressurization / exhaust procedure is defined as the wetting degree of the drying object or
The vacuum drying method according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the setting is changed according to the form of the object to be dried. 9. The method according to claim 1, 2, 3, wherein the time required for each cycle is changed in time series according to the degree of wetting of the object to be dried, its material characteristics and / or its form.
4, 5, 6, 7 or 8 vacuum drying method. 10. The maximum temperature in the steaming procedure in each cycle is changed in time series according to the degree of wetness of the object to be dried and the temperature characteristic of the material. Vacuum drying method of 5, 6, 7, 8 or 9. 11. In the heating procedure or the steaming procedure, when it is confirmed that the accommodation space of the chamber is in a supersaturated state of steam based on the indicated values of the temperature sensor and the humidity sensor, the valve is appropriately switched to the ventilated state. The vacuum drying method according to claim 2, 3, 4, 5, 6, 7, 8, 9 or 10.