JP2005287373A - Dry-sterilizing device using reduced pressure superheated steam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry-sterilizing device using reduced pressure superheated steam, having a high drying capacity, capable of coping with by a small-sized facility, drying a material weak for heat degeneration such as foods, also especially keeping a form before the drying and further performing sterilization well. <P>SOLUTION: This dry-sterilizing device is constituted by a vacuum pump D for reducing pressure in the device, a steam tank A generating steam under the reduced pressure generated by the action of the vacuum pump D, a heater B for heating the reduced pressure steam to make the reduced pressure superheated steam and a drying device body C for drying the materials to be dried, such as the foods. The reduced superheated steam is flown into the drying device body C for drying the materials to be dried (a) in a standing still state by the reduced pressure superheated steam. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention uses a vacuum superheated steam that has a high drying capacity, can be handled with small equipment, can be dried even with foods that are vulnerable to thermal denaturation, can maintain the shape before drying, and can be well sterilized. The present invention relates to a dry sterilization apparatus.

  As a drying method that is more efficient than conventional methods, a method of increasing the temperature of hot air to increase the temperature difference from the temperature of an object to be dried and a method of using superheated steam are known. Superheated steam is characterized by a higher drying rate than using hot air, but it needs to be 170 ° C. or higher under atmospheric pressure to exert its effect, and can be applied in food drying. Currently there are few products.

There is also a vacuum drying method. When the raw material is vacuum-dried by this method, the air is in a state of being lost, and how to transfer heat is usually a direct heat transfer method that transfers the heat on a plate. In this case, the plate must be enlarged. Furthermore, in order to prevent the shape of the raw material from collapsing under vacuum conditions, it is necessary to heat it slowly over time, and there is a disadvantage that it takes drying time. was there. As another vacuum drying method, there is a vacuum freeze-drying method (freeze-drying). However, compared with the above-mentioned vacuum drying, a freezing process is added, so that it takes more time to dry, and the equipment becomes larger, and at low temperatures. There was a problem that it could not be sterilized. Moreover, in patent document 1, since it was high temperature, it was unsuitable for food drying.
JP 2002-62044 A

  However, in particular, foods and the like are required to be able to dry even those that are vulnerable to heat denaturation, in particular to be able to maintain their shape and to be sterilized. For this reason, the problem (technical problem or purpose) to be solved by the present invention can be dried even if it is vulnerable to heat denaturation, and in particular, the shape before drying can be maintained and sterilization can be achieved. It is to respond.

Accordingly, as a result of earnest and research to solve the above problems, the inventor of the present invention has a vacuum pump for reducing the pressure inside the apparatus, and a steam tank for generating steam while the pressure is reduced by the operation of the vacuum pump. A heating heater that heats the reduced-pressure steam to produce reduced-pressure superheated steam, and a drying device main body that dries food to be dried, and the reduced-pressure superheated steam flows into the drying device main body to reduce the pressure. The above-mentioned problems have been solved by providing a dry sterilization apparatus using reduced-pressure superheated steam, wherein the object to be dried is dried in a standing state with superheated steam.

Moreover, the said subject was solved by setting it as the dry sterilization apparatus using the pressure reduction superheated steam characterized by the said pressure reduction superheated steam being about 50 degreeC thru | or about 150 degreeC in the said structure. Furthermore, in the said structure, it was set as the dry sterilization apparatus using the decompression superheated steam characterized by providing the cooling capacitor which condenses a part of said decompression superheated steam between the said drying apparatus main body and the said vacuum pump. This solves the problem. In the above-mentioned configuration, a drying condenser using a reduced pressure superheated steam, wherein a cooling condenser and a cooling unit for condensing a part of the reduced pressure superheated steam are provided between the drying apparatus main body and the vacuum pump. By using the apparatus, the above-mentioned problems are solved.

  In the invention of claim 1, the drying ability is high, it can be handled with small equipment, and even foods that are vulnerable to heat denaturation such as food can be dried, in particular, the shape before drying can be maintained and sterilization can be performed. Play. Further, in the invention of claim 2, the temperature is easy to operate as drying of food and sterilization is possible. Furthermore, the invention of claim 3 has an advantage that it can be handled with a smaller equipment. Moreover, in invention of Claim 4, there exists an effect which can respond with a small installation.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of the present invention, mainly a steam tank A, a heating heater B, a drying apparatus main body C, The vacuum pump D, the cooling condenser E, and the cooling unit F are comprised. Further, the minimum configuration includes a steam tank A, a heating heater B, a drying apparatus main body C, and a vacuum pump D. Basically, the depressurized superheated steam is allowed to flow into the drying apparatus main body C and is used as a heat source to dry and sterilize the material to be dried a in the drying apparatus main body C.

  The steam tank A is provided with a steam jacket 2 around the tank body 1 and heated. The tank body 1 is provided with a supply water tank 3 that stores water (for example, ion exchange water, pure water, etc.) that does not contain impurities used as steam. From the steam tank A, steam is generated as decompressed steam while being decompressed by the operation of the vacuum pump D. Further, a reduced pressure steam supply pipe 4 is provided between the steam tank A and the drying apparatus main body C. Specifically, a heating heater B (electric heater, steam heater, oil heater, etc.) is interposed in the middle of the decompression steam supply pipe 4, and the first decompression is performed between the steam tank A and the heating heater B. It is called a steam supply pipe 4a, and the decompression steam supply pipe 4 between the heating heater B and the drying apparatus main body C branches in the middle, and the heating heater B side is connected to the second decompression steam supply pipe 4b. And the said drying apparatus main body C side is each called the 3rd pressure reduction steam supply piping 4c.

  Further, a reduced-pressure steam suction pipe 5 is provided between the drying apparatus main body C and the vacuum pump D. Specifically, a cooling condenser E is interposed in the middle of the reduced-pressure steam suction pipe 5. The decompression steam suction pipe 5 between the drying apparatus main body C and the cooling condenser E branches in the middle, the first decompression steam suction pipe 5a on the drying equipment main body C side and the second decompression on the cooling condenser E side. It is called the vapor suction pipe 5b. Further, a space between the cooling condenser E and the vacuum pump D is referred to as a third reduced-pressure steam suction pipe 5c.

Further, switching valves V ₁ and V ₂ are provided at a branch point of the reduced-pressure steam supply pipe 4 and a branch point of the reduced-pressure steam suction pipe 5, respectively. A decompression steam escape pipe 6 is provided between the branch points. The cooling condenser E is provided with a cooling unit F, and is provided with a cooling water supply pipe 7 and a cooling water return pipe 8. The cooling unit E may not be provided with the cooling unit F. Reference numeral 9 denotes an exhaust pipe of the vacuum pump D. Reference numeral 10 denotes a condensed water drain tank.

  As shown in FIGS. 3 to 6, the drying apparatus main body C causes the depressurized superheated steam to flow into the inside through the third depressurized steam supply pipe 4 c from the lower side of the drying case 20, and From the upper side of 20, it continues to the first vacuum steam suction pipe 5 a. Further, the dry casing 20 is provided with a plurality of plate-like partition layers 21, and a rear circulation space 23 is provided on the rear side of the multilayer partition layers 21, 21,... Via a rear partition wall 22. It has been. Further, side flow spaces 25, 25 are provided on both side portions of the multilayer partition layers 21, 21,... Via side partition walls 24, 24, respectively. The rear partition wall 22 has an inflow opening 22a, and the side partition walls 24, 24 have a plurality of discharge holes 24a, 24a,. A drying ridge 26 is accommodated between the partition layers 21 and 21 so that it can be taken in and out from the front side. An object to be dried a such as a food is placed in the drying jar 26.

  The drying apparatus main body C has the above-described configuration, and the depressurized superheated steam from the lower side of the drying casing 20 flows between the rear circulation space 23 and the inflow opening 22a between the upper and lower partition layers 21 and 21. In addition, the depressurized superheated steam is in contact with the drying trough 26 accommodated therein evenly. The to-be-dried object a is dried and sterilized using the reduced pressure superheated steam as a heat source.

  The operation of the present invention will be described. First, steam is generated from the steam tank A as decompressed steam while the pressure is reduced by the operation of the vacuum pump D. At this time, water (for example, ion-exchanged water, pure water, etc.) that does not contain impurities used as reduced-pressure steam is allowed to flow into the steam tank A. The decompressed steam (for example, about 38 ° C.) from the steam tank A is decompressed (for example, −95 kPa). The reduced-pressure steam is heated by the heating heater B (for example, about 75 ° C.), and becomes reduced-pressure superheated steam. The point is that this is depressurized superheated steam.

As shown in FIG. 2A, the switching valves V ₁ and V ₂ are switched to the normal operation type so as to circulate through the third reduced pressure steam supply pipe 4c, the drying apparatus main body C, and the first reduced pressure steam suction pipe 5a. Then, the depressurized superheated steam (for example, about 75 ° C.) is brought into contact with an object to be dried a such as food in the drying apparatus main body C to dry and sterilize the object to be dried a. This dry state is stationary drying. That is, the object to be dried a in the drying ridge 26 is dried without moving.

  Such stationary drying is performed, and the reduced pressure superheated vapor (for example, about 67 ° C.) accompanied by moisture evaporated from the dried object a such as food is cooled by the cooling condenser E (for example, about 25 ° C.). ), Moisture is condensed and enters the condensed water drain tank 10. Further, the depressurized superheated steam from the cooling condenser E is exhausted from the vacuum pump D through an exhaust pipe 9.

Further, as shown in FIG. 2 (B), the switching valves V ₁ and V ₂ are switched to the operation stop type, and the reduced pressure superheated steam does not pass through the drying apparatus main body C, and the reduced pressure steam escape pipe 6 is connected. Through the cooling condenser E and exhausted from the vacuum pump D through the exhaust pipe 9. When the drying object a such as food in the drying apparatus main body C is completely dried, the drying basket 26 is pulled out and the drying object a is taken out.

In order to measure the degree of drying, although it is an embodiment, the drying basket 26 and the entire drying apparatus main body C containing the material to be dried a such as food are weighed by the weighing machine 15 before and after drying. In some cases, the weight of the raw material is grasped and the drying condition is checked. Then, a dried product a such as a new food is put in the drying jar part 26 and the drying jar part 26 is stored in the drying apparatus main body C. From this state, the switching valves V ₁ and V ₂ are switched to the normal operation type to perform drying and sterilization.

  As described above, in the present invention, the drying capacity is high, and it can be handled with a small facility. This is a comparison with the case of vacuum drying. Vacuum drying is a direct heat transfer method that is carried on a plate and has a low drying capacity. For this reason, in the present invention, the equipment cost can be relatively reduced. In addition, compared to superheated steam (about 170 ° C.) under atmospheric pressure, the product can be heated while keeping the product temperature low, so that even foods that are vulnerable to heat denaturation such as food can be dried. In particular, the shape of the food before drying can be maintained. Furthermore, even if the temperature of the food product itself is low, a sterilizing action can be obtained because of drying at about 50 ° C. to about 150 ° C.

When cocoon is used as a raw material that is thermally denatured and crushed when dried at normal pressure. When normal pressure drying (air-drying) was performed, the surface turned white in less than 10 minutes at a set temperature of 70 ° C., and even after 24 hours, only the vicinity of the surface was dried, and the internal moisture remained. By raising the set temperature to 90 ° C. and carrying out finish drying for about 6 hours, a dry product could be obtained, but it was dark brown flat.
When this apparatus was used to dry the drying case 20 of the drying apparatus main body C at -90 to -95 kPa and a reduced pressure superheated steam temperature of 70 ° C., the drying was completed in about 16 hours. Further, although the size was reduced by about 10%, a product was obtained in which the fresh shape was maintained and the color remained vivid red.

When maiko (size as harvested, 70-120 g per stock) is used as a raw material that is dried at normal pressure.
In the case of normal pressure drying (aeration drying), the drying was completed at a set temperature of 70 ° C. for about 8 hours. Although the size is about 10% smaller, the shape of the product is maintained and no noticeable discoloration is observed. It feels very fresh.
On the other hand, when the inside of the drying case 20 of the drying apparatus main body C was kept at -90 to -95 kPa and the reduced pressure superheated steam temperature of 70 ° C. using this apparatus, the drying was completed in about 8 hours. In comparison with the atmospherically dried product at this time, the freshness is the same level or more, and the apparatus is finished more plumply.

Therefore, when both samples were pulverized and the number of viable bacteria was examined, the following differences were observed.
Test target Number of coliform bacteria Number of general bacteria Normal pressure dry (aeration dry) product 300 or less / g 4000 / g
Depressurized superheated steam dried product 300 or less / g 300 or less / g
From this, it can be seen that the finished state is the same for objects that can be sun-dried, but for sterilization effect, it is not necessary to introduce a new sterilizer and can be distributed in the market for a long time The merit of introducing this device is great.

  Although it is the structure which combined the vacuum drying of the prior art, and the superheated steam stationary drying of the prior art, it is an invention which shows especially a remarkable effect. That is, the drying capacity is high compared to vacuum drying, and it can be handled with small equipment. In vacuum drying, it is a direct heat transfer method that is carried on a plate, and the drying capacity is low. The drying capacity can be increased while the equipment cost is relatively cheap. In addition, compared to superheated steam (about 170 ° C.) under atmospheric pressure, the product can be heated while keeping the product temperature low, so that even foods that are vulnerable to heat denaturation such as food can be dried. In particular, the shape of the food can be maintained. Furthermore, there are many advantages that a sterilizing action can be obtained because of drying at about 50 ° C. to about 150 ° C. even if the temperature of the food itself is low, and the industrial applicability is extremely large.

It is a block diagram of the present invention. (A) is a block diagram which shows the action | operation state of the main member related to the switching valve made into the normal operation state, (B) is a block diagram which shows the action state of the main member related to the switch valve made into the operation stop state. It is principal part sectional drawing of a drying apparatus main body. (A) is a perspective view of a drying apparatus main body, (B) is the perspective view which a part of drying apparatus main body cut away. (A) is a cross-sectional top view of a drying apparatus main body, (B) is XX arrow sectional drawing of (A). (A) is a principal part perspective view of a drying apparatus main body, (B) is a principal part perspective view of the drying apparatus main body except the drying ridge part in (A).

Explanation of symbols

A ... Steam tank, B ... Heating heater, C ... Dryer body, D ... Vacuum pump,
E: Cooling condenser, F: Cooling unit.

Claims (4)

A vacuum pump that depressurizes the inside of the apparatus, a steam tank that generates steam while being depressurized by the operation of the vacuum pump, a heating heater that heats the decompressed steam to form depressurized superheated steam, and a food to be dried A drying apparatus body for drying an object, wherein the depressurized superheated steam is allowed to flow into the drying apparatus body and the object to be dried is dried in a stationary state with the depressurized superheated steam. Dry sterilizer using steam. The dry sterilization apparatus using reduced-pressure superheated steam according to claim 1, wherein the reduced-pressure superheated steam is about 50 ° C to about 150 ° C. 3. The dry sterilization apparatus using reduced-pressure superheated steam according to claim 1 or 2, wherein a cooling condenser that condenses a part of the reduced-pressure superheated steam is provided between the drying apparatus main body and the vacuum pump. The drying using reduced pressure superheated steam according to claim 1 or 2, wherein a cooling condenser and a cooling unit for condensing a part of the reduced pressure superheated steam are provided between the drying device main body and the vacuum pump. Sterilizer.

Images