JPS61180881A - Rotary drum type vacuum hot-air circulating drying method - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides an air blower that stores materials to be dried inside a rotating drum and connects the rotating drum to the rotating drum while continuously or intermittently rotating the drum. Driving to force indoor air to the outside @
At the same time, outside air is heated and introduced into the drying chamber, and the atmosphere inside the rotating drum is maintained at a predetermined vacuum state due to the difference between the amount of air being exhausted and the amount of air flowing in. The present invention relates to a rotating drum type vacuum hot air circulation drying method in which an object to be dried is dried while circulating air inside a rotating drum through an object to be dried stored in a rotary drum.

<Conventional technology> Conventionally, the material to be dried is stored inside the drum that rotates once.

A rotating drum type hot air drying device that dries the material to be dried using hot air is a device that dries under open atmospheric pressure.

<Problems to be Solved by the Invention> It is widely known that the color and taste of the dried tea confectionery can be improved by drying tea in high altitude mountainous areas with low atmospheric pressure. The results also show that the difference in water column height on a water column manometer is lOO~5.
When the plants were dried under vacuum conditions of about 00 Aq (Zoo to 500 Aq), drying efficiency was improved and dried products with good color and taste could be obtained.

Therefore, good drying efficiency can be achieved by storing the material to be dried inside a rotating drum and artificially providing the same conditions inside the rotating drum as in mountainous highlands while rotating the rotating drum continuously or intermittently. Moreover, it is possible to dry plants with good color and taste.

The present invention stores the material to be dried inside a one-rotation drum, and while rotating the drum continuously or intermittently, the interior of the one-rotation drum is adjusted to 1 in the water column height difference measured by a water column manometer.
It enables hot air drying under vacuum conditions of about 00 to 500 mAq (100 to 500 mAq).

<Means for Solving the Problems> An embodiment of the vacuum hot air circulation drying apparatus according to the present invention will be specifically described with reference to the accompanying drawings.

1 is a rotating drum, and rails 2 and 3 are provided on the left and right sides of the outer circumference of this drum, and the zero-rotation drum is supported by two pairs of guide rollers 5, 5 and 6, 6 arranged on a machine frame 4. 1 is closed by mirror plates 7 and 8, one of the mirror plates 7 has a Cheno foil 9, and the other mirror plate 8 has an exhaust port 10 and an air inlet 1.
1 and four exhaust fans 12, 1 are installed at the exhaust port 10.
2. ... are connected in series, and the air inlet 1
1 is provided with an air heating device 13.

Inside the rotating drum, a porous and ventilated partition wall 14 made of wire mesh, punched steel plate, etc. is provided near the mirror plate 8.

A drying chamber 15 is formed between the end plate 7 and a blower chamber 24 is formed between the end plate 8, and a porous air passage 16 made of wire mesh or punched steel plate is provided at the bottom of the drying chamber 15. One of them communicates with a circulation blower 17 via a partition wall 14 .

The drum 1 is provided with an input port 18 at the top and an opening/closing lid 19 that covers the opening and closing, and the opening/closing lid 19 is sealed when the drum 1 is rotating and drying, and when the material to be dried is loaded or taken out. It should open.

Also, at the bottom of the drum 1 is a belt conveyor 20 for taking out.
is placed horizontally, and the drum 1 is rotated to open an opening/closing lid 19 provided at the input port 18 to transfer and take out the dried material discharged onto the take-out belt conveyor 2o. The drum 1 is connected to and driven by a motor 21 provided on the machine frame 4 via a chino 22. 23 is the temperature aSI,
Reference numeral 25 is an electric control panel that communicates with the heater of the air heating device 13 to control the heater, and 26 is a slip ring that supplies electricity to the electric control panel 25 of the rotating drum 1.

<Operation> Stop the drum 1 at the stop position and open the rl of the upper input port 18.
The 1M lid 19 is opened and the material to be dried is introduced using a supply device such as a packet elevator or a belt conveyor.

When this input is completed, the opening/closing lid 19 is closed and sealed, and the exhaust fans 12, 12, . . . , circulation fan 17, air heating device 13, and motor 21 are started to start drying. Exhaust fan12.
12..., the air inside the rotary drum 1 is continuously expelled to the outside, resulting in a negative pressure inside the rotary drum 1, and the outside air is heated by the air heating device 13 and flows into the inside of the rotary drum 1. Then, the air inside the drum is sent under pressure by a circulation blower 17 to a porous and breathable air passage 16 for materials such as wire mesh or punched steel plates. It flows into the blower chamber 24 through the porous and breathable partition wall 14, and the exhaust fan 1
2.12..., and a part of the heated air is sucked into the circulation blower 17 along with the heated air flowing in from the outside via the air heating device 13.

It is possible to dry the rotary drum 1 while continuously rotating it, or to dry it while repeatedly stopping it for one rotation, or to dry it by stopping the rotary drum 1 at a stop position and then rotating it for a certain period of time.

After spreading and mixing the material to be dried inside the rotary drum 1, the rotary drum 1 is again stopped at the stop position and drying is repeated, etc.
It can be freely selected depending on the type, shape, moisture content, etc. of the material to be dried.

The exhaust fan 12 used in this example has the characteristics shown in the figure, and has a static pressure of 60 m'/
Exhaust capacity of m (at rotation speed of 3600r, p, m)
When four of these exhaust fans 12 are connected in series, the air inside the rotating drum 1 is sucked in and exhausted to the outside, and the inflow of air is blocked, the inside of the rotating drum is equal to the water column height difference in the water column manometer. , a vacuum state of approximately 500m+Aq is created.

From this state, while letting outside air flow in from the outside, the inside of the rotating drum 1 has a water column height difference of 310 m as measured by a water column manometer.
The resistance value of the passage resistance of the incoming air flowing into the rotating drum while being heated by the air heating device [13] is set so as to maintain a vacuum of (310 ma+Aq). By providing the passage resistance at the time of inflow as described above, the number of operating exhaust fans 12 can be reduced from 4 to 3 to 2, thereby reducing the amount of air flowing in from the outside and the vacuum inside the rotating drum. The table below is shown.

Operating status of exhaust fan Incoming air volume Vacuum volume inside drum/m
■A (1 2 units in operation (2 units stopped) 6.6 1503 units in operation (1 unit stopped) 7.5 2254 units in operation
9.0 By reducing the number of 310 wandering fans in operation from 4 to 3 to 2, the amount of air flowing in from the outside, that is, the amount of air ventilating the inside of the rotating drum, will be 6.6 to 9. 0rrr/m, and the vacuum inside the rotating drum is 150~
It can be set to 310 ■Aq (150 to 310 ■Aq). Also, by changing the rotation speed of the exhaust fan,
The same effect as changing the number of operating exhaust fans described above can be obtained.

<Effects of the invention> To briefly explain the effects of the invention in the final drying of tea production, in which rough tea with a moisture content of about 10% is dried to a moisture content of 4 to 5%, the tea confectionery that is dried and processed at the producing farm has a moisture content of 4 to 5%. This rough tea is dried to 4 to 5%, and the water stems and hard leaves that impair the taste and appearance of the tea are removed, which is called tea finishing, and the shape of tea confectionery is changed. The products are prepared by aligning and blending the products. Conventionally, a continuous dryer with a ventilation band conveyor is used, and the drying takes about 40 minutes with hot air at about 100 degrees Celsius, thus avoiding deterioration of the color of the tea and sweets. It was impossible.

In the method according to the present invention, the amount of tea to be finished on the first day (usually about 2 tons to 5 tons) is stored in a rotating drum by the rotating drum type vacuum hot air circulation drying method according to the present invention after the work is completed, While starting work the next day,
It enables long-time drying at low temperatures under vacuum conditions, and after completion of drying, it allows continuous tea finishing work while discharging the required amount from the rotating drum, and serves as a storage device and fixed-quantity supply device. This also contributes to the rationalization of tea finishing plants.

In the large-scale apparatus used in this method, approximately 5 tons of tea confections are stored in a rotating drum with a capacity of 30 rrr, and 40 to 6
Drying is completed in 12 hours while circulating hot air at 0°C.

First, in the first half of the process, by setting the first process drying time timer switch to 4 hours, four exhaust fans are operated to circulate hot air at 60° C. for drying. Therefore, the degree of vacuum is increased and the amount of ventilation (amount of air exchanged in the drying room) is increased to speed up the initial drying of the tea confectionery and avoid the generation of strange odors and discoloration.

Next, in the intermediate second step, the second step drying time timer switch is set to 4 hours, the same as the first step, and three exhaust fans are operated and one exhaust fan is stopped, so that the evaporated moisture is removed. As the temperature decreases, the degree of vacuum is lowered and the amount of ventilation is also reduced to circulate hot air at 50°C for drying.

Next, in the second half of the third step, the second step drying time timer switch was set to 4 hours, and the evaporated moisture was continuously reduced by operating two exhaust fans and stopping the two exhaust fans. The degree of vacuum is low and the amount of ventilation is further reduced to circulate hot air at 40°C to complete drying.

Also, throughout each drying process, 1 usually stops at a stop position,
By rotating the rotary drum about 10 degrees once every hour, the confectionery contained therein is mixed and uneven drying is prevented.

As mentioned above, the temperature of the circulating hot air is lowered over time according to the program built into the timer, and the number of operating units and rotational speed of the exhaust fan is reduced. Replacement amount (ventilation amount)
By sequentially changing the drying process and completing the drying while mixing the tea confectionery contained therein by appropriately rotating the rotary drum, it is possible to prevent quality deterioration such as discoloration of the tea confectionery and generation of strange odors.

In addition, when drying objects whose shape cannot be destroyed by the rotation of the rotating drum, such as orange peels and grains, or objects whose shape can be destroyed, the rotating drum is continuously rotated during the drying time. Drying time can be shortened by improving air permeability between the layers.

[Brief explanation of drawings]

The drawings show an embodiment of the rotary drum type vacuum hot air circulation drying method according to the present invention. 1. Rotating drum 2, 3. Rail 4. Machine frame 5
．． 6. Guide roller 7. 8. End plate 9. Cheno wheel 10. Exhaust port 11. Air inlet 12.
・Exhaust fan 13... Air heating device 14... Partition wall 15
・・Drying room 16・・Air duct 17・・Circulation blower 18
...Input port 19...Input lid 20...Belt conveyor
21...Softnight 22...Cheno 23...Temperature regulator 24...Blower room 25...Electric control panel 26...Slip ring patent applicant Kuni Okamura Original drawing engraving (no changes to the content) Income Procedural amendment 1 Indication of the case 1985 Patent Application No. 17957 2 Name of the invention Rotating drum type vacuum hot air circulation drying method 3 Person making the amendment Relationship to the case Patent applicant Address (residence) 3 Takayanagi, Fujieda City, Shizuoka Prefecture -30-23 Address (residence)

Claims (2)

[Claims] (1) A rotating drum with both ends of the cylinder closed by mirror plates is arranged on the machine frame and supported rotatably, and the rotating drum is connected to a drive source to rotate the rotating drum continuously or intermittently, and further rotates. The drum has an exhaust port and an air inlet,
For the amount of air exhausted from inside the rotating drum to the outside by operating one or several exhaust fans connected to the exhaust port,
As the air inside the rotating drum is removed, the outside air is heated by an air heating device through an air inlet provided in the rotating drum, and the passage resistance when flowing into the rotating drum is set to a predetermined resistance value. , maintaining the amount of outside air flowing in to a smaller amount than the amount of air exhausted from the inside of the rotary drum, and increasing the air temperature inside the rotary drum while continuously maintaining the inside of the rotary drum at a desired degree of vacuum;
A rotary drum type vacuum hot air circulation drying method characterized in that a circulating blower is attached to promote drying while circulating the air inside the rotary drum through the material to be dried stored in the rotary drum. (2) Drying is carried out while adjusting the degree of vacuum inside the rotating drum and the amount of air exchange inside the rotating drum to predetermined target values by adjusting the number of operating units and rotation speed of the exhaust fan. A rotating drum type vacuum hot air circulation drying method according to Item 1.