JPS61223480A - vacuum belt dryer - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] The present invention relates to a vacuum belt dryer, and more specifically to a vacuum belt dryer for drying liquid, slurry or paste raw materials under vacuum and extracting them as granular dry products. The present invention relates to a vacuum belt dryer.

In recent years, with the diversification of dietary habits, a large number of processed food materials and instant foods of type P1 have become commercially available. In this field of food processing, it is important to maintain the solubility and ready-to-ready properties at a specified level when consumers use the product as a cooking ingredient, and to ensure that the final product does not suffer from deterioration in quality or alteration of ingredients. Various normal pressure drying devices and vacuum drying devices are used for the purpose of imparting restorability. Among such drying devices, attention has been paid to the fact that it is relatively easy to maintain the solubility of products as cooking ingredients at a good level, and the field of use of vacuum drying devices is rapidly increasing. Spray dryers and freeze dryers are known as general-purpose vacuum drying equipment, but while the former has low drying costs, it has somewhat poor performance in maintaining product solubility and quality or preventing changes in components. On the other hand, the latter method employs a freezing/sublimation process, resulting in problems such as a complicated structure and a rise in drying costs. Here, as a means of solving the practical problems recognized in the above spray dryers and freeze dryers,
This led to a request for the development of a vacuum belt dryer. A vacuum belt dryer is equipped with a heating zone and a belt conveying device in a vacuum container, and feeds food material in the form of a liquid, slurry, or paste onto an endless conveyor belt in the form of a thin film, and rotates the endless conveyor belt. The food material is introduced into the heating zone by the heating zone, and is vacuum-dried under drying conditions at a relatively low temperature. At this time, the food material placed in a thin film form on the belt undergoes a strong evaporation phenomenon of the water contained inside, causing the food material to swell and form numerous ventilation holes inside. , which is sent to the crusher as a porous intermediate product. In this way, the usefulness of the vacuum belt dryer is being recognized by the second son as an alternative technical means to conventional spray dryers and freeze dryers.

(°5) Vacuum belt dryers can significantly outperform known spray dryers and freeze dryers in terms of quality retention, prevention of component changes, and reduction in drying costs. However, in order to respond to the diversification of food materials to be subjected to drying processing, there are many points that require further improvements in terms of structure and function.

First, the first problem is that when feeding food raw materials prepared in the form of slurry or paste, in conventional raw material supply devices, the raw material discharge nozzle oscillates at a substantially constant oscillating speed. At the same time, the raw materials are placed on the endless conveyor belt (therefore, as shown in FIG. When a raw material placed on an endless conveyor belt forming an overlapping part with a relatively large thickness is subjected to drying treatment under the same heating conditions as other thinner parts, the increase in thickness causes the overlapping part to dry. On the other hand, if the heating temperature is set high to suit the above-mentioned overlapping areas, other thinner areas will become over-dried. This causes problems such as deterioration in quality and deterioration of quality.

The second problem is that the endless conveyance means consisting of an endless conveyor belt and its driving roller moves at a constant speed from the raw material supply station toward the drying station, and the thin film-like raw material supplied onto the endless conveyor belt is Although it is configured to be able to transmit thermal energy for drying, in reality, the endless conveyor belt is often placed in an unstable driving state with meandering and warping (although once this When such a phenomenon occurs, the conditions for supplying the raw materials onto the endless conveyor belt become extremely unstable, and due to fluctuations in drying conditions, defects such as quality deterioration and deterioration of ingredients occur in the final product.

The third problem is that the end of the endless conveyance means is usually equipped with a device for peeling and crushing intermediate products, such as a rotating blade, but the existing device has a complicated structure and has limited peeling and crushing ability. This was insufficient, resulting in defects such as non-uniform particle size and reduced yield in the final product.

The main object of the present invention is to provide a vacuum belt dryer having a component structure and a stable drying function, which can solve the above-mentioned problems observed in conventional vacuum belt dryers. It is in.

In view of these objectives, the present invention is a vacuum belt dryer for vacuum drying raw materials prepared in a liquid, slurry or paste form and taking out a dried product in the form of granules. A rotary arm (2), a nozzle (3), and a swing speed control mechanism (4) for the nozzle are arranged along the movement path of an endless conveyor belt (1) made from a textile fabric from the raw material supply side to the product delivery side. A raw material supply device consisting of (
5) and multiple heating plays) (6a), (6b),
(6C), a vacuum drying/cooling device (8) formed by a single cooling plate (7), and a fluid pressure cylinder mechanism (
9) and a shear blade (10).
) are sequentially arranged, and a meandering and warping prevention mechanism (12) is attached to the drive device of the endless conveyor belt (1), and further below the pre-crusher (11),
A main crusher (15) consisting of a rotating blade (13) and a mesh wire mesh (14) arranged to surround the rotating blade (13) approximately halfway around it, and a product take-out chamber (17) having a vacuum locking mechanism (16). The gist is a vacuum belt dryer arranged in sequence.

Raw materials for processed foods prepared in the form of liquid, slurry or paste are fed in a thin film form onto the endless conveyor belt (1) in a meandering trace without forming any overlapping parts, thereby preventing meandering and warping. The endless conveyor belt (
1) is vacuum dried in a drying/cooling device (8) by constant speed movement, and then crushed into granules by a pre-crusher (11) and a main crusher (15), and a product take-out chamber having a vacuum locking mechanism (16). (1
7) is taken out of the system in a batch manner.

11 FIG. 1 is a partially sectional front view illustrating the overall structure of the apparatus of the present invention. Moreover, FIGS. 2 to 6 are explanatory diagrams of the detailed structure of the apparatus of the present invention.

In Fig. 1, the main body (18) of the vacuum container includes a vacuum generator (18) consisting of a known vacuum pump (19), a cold trap (2G), and a chiller unit (21).
28) is provided, and by operating the vacuum generator, a vacuum level of approximately 10 Torr can be maintained within the main body (18) of the vacuum container during drying of raw materials.

On the other hand, inside the main body (18) of the vacuum container, there are first to first channels, each of which has a hot water flow path formed therein, from the raw material supply side to the product delivery side along the movement path of the endless conveyor belt (1). 3
Heating plates (6a), (6b), (6G) and cooling plates (7) each having a cooling water flow path formed therein are arranged in sequence, and the heating plates (6a), (6b), (6G) and Vacuum drying device (8) consisting of a cooling plate and a cooling plate.
In order to supply hot water and cooling water adjusted to a predetermined temperature, the main body (18) of the vacuum vessel is equipped with a known tube type or body plate type heat exchanger (18) which functions as a hot water circulation line heater. 22) A heating medium and cooling medium circulation device is connected, which consists of an expansion tank (23) that promotes hot water Φ circulation by pressurizing air, and a circulation pump (24) connected to a temperature control circuit (not shown). ing.

As shown in Fig. 2, the endless conveying device basically consists of a motor (25), a drive roller (26), a driven roller (27), and a knitted or woven fabric made of synthetic fiber yarn, such as polyester fiber yarn. The mesh belt (1) is connected to the drive roller (26) and the driven roller (27).
) by configuring a drive system that is wound around 0.0
A constant speed conveying device is formed having a conveying speed of 5 to 5.5 m/s+in. The mesh belt (1) is manufactured from a knitted fabric made of synthetic fiber yarn with excellent strength, coefficient of friction, heat resistance, and heat conductivity in consideration of the general characteristics required for an endless conveying device. In order to maintain the releasability of vacuum-dried intermediate products, the prevention of leakage of raw materials and intermediate products from the weave and stitches, and the washability at a specified level, endless polyester multifilament yarn woven fabrics are used. We manufacture conveyor belts.

Drive roller (26) and driven roller (27)
is the mesh belt (1) inside the body (18) of the vacuum container.
It is necessary to be able to guarantee a stable conveyance posture without meandering. For this reason, the surfaces of the drive roller (26) and the driven roller (27) are crowned so that the diameter at the center is somewhat larger than the diameter at the ends, and the axis of the driven roller (27) is The pressure cylinder mechanism (29) is connected to a belt tension unit having, for example, an air cylinder mechanism, and forms a tension adjustment mechanism for the mesh belt (1). Further, on the side where the mesh belt (1) is drawn into the drive roller (26) and the driven roller (27), a mesh belt (
When a meandering phenomenon occurs in 1), the mesh belt (1)
Four door wheels (30) are rotatably arranged opposite to each other in pairs for transmitting a restoring pressing force inward to the edge portions, so-called ears. These components are assembled into an integral structure to create a meandering prevention mechanism (12
) is formed.

On the other hand, if the mesh belt (1) warps due to tension imbalance or thermal contraction, the heating plate (6a)
(6b), (6c) and the spacing between the cooling plate (7) and the mesh belt (1) vary along the width direction of the mesh belt (1), causing quality deterioration of the product due to uneven drying. In order to avoid such obstacles, the heating plate (said heating plate) along the movement direction of the mensch belt (1)
(6a), (6b), (6c) and cooling plate (
7), a plurality of presser rollers (31) for pressing the mesh belt (1) are placed at appropriate intervals from the raw material loading surface of the mesh belt (1), and the drive roller (26) and the driven It is rotatably supported via a support bracket (not shown) in alignment with the axial direction of the roller (27). This presser roller (31) works together with the meandering prevention mechanism (12) to prevent the mesh belt (1
) functions as a warping prevention member. The raw material supply device (5) is disposed at the most upstream side of the moving path of the endless conveyor belt (1), and is connected to the rotating shaft of the motor (32) as a swing speed control mechanism (4) of the nozzle (3). As shown in FIG. A forward/reverse rotation speed reducer (35) is connected to the nozzle (3) for changing the direction of the oscillating motion of the nozzle (3). Such a rocking speed? Rotating arm (2) via 11111 mechanism (4)
The nozzle (3) is swingably supported at a predetermined distance from the upper surface of the mesh belt (1), and the raw material stored in the raw material tank (36) is connected to the raw material tank (36). The pulp reaches the nozzle (3) via the raw material supply pulp (37), and is meanderingly placed on the mesh belt (1) in a liquid, slurry or paste state due to the oscillating motion of the nozzle.

In the apparatus of the present invention, the two sets of proximity switches (33), ( When the direction change point of the swing stroke of the nozzle (3) is detected by 34), the forward/reverse rotation reducer (35) of the swing speed 1i1gtJ mechanism (4)
is temporarily stopped, and as shown in FIG. The configuration of the serpentine feed trace is controlled so that the raw material is given a feed trace oriented in the longitudinal direction of the mesh belt (1) near the edge of the mesh belt (1). .

Furthermore, in the device of the present invention, the forward/reverse rotation reducer (35
) by adjusting the reduction ratio of the mesh belt (1) to the running speed of the mesh belt (1), even when drawing the conventional feed trace shown in Fig. It is possible to obtain a meandering form of the raw material in which almost no thickened portion occurs.

On the other hand, the vacuum drying path formed by the endless conveyor belt (1) includes a heating plate (6a), (6
b), (6C) and a hot water circulation type vacuum drying/cooling device (8) consisting of a cooling plate (7) with a built-in cooling water flow path.
is located.

The saI-like raw material introduced into the first heating zone constituted by the first heating plate (6a) contains a large amount of water, which is transferred from the high temperature hot water flowing inside the heating plate (6a). Thermal energy causes water to evaporate on the surface and inside the raw material at the same time, causing the raw material spread into a thin film to expand rapidly and undergo vacuum drying. Since this first heating zone is maintained at a constant rate of dryness, the temperature of the raw material itself hardly rises, and the raw material is sent to the subsequent heating zone (1) in a state in which approximately half of its retained moisture has been evaporated.

Second heating plate (6b) forming the No. 1 heating zone
Hot water at a slightly lower temperature than the hot water supplied to the first heating plate (6a) is introduced into the first heating plate (6a), and most of the water contained in the raw material is evaporated by constant rate drying. Therefore, the expanded thickness and surface shape of the raw material hardly change, the surface of the raw material hardens to some extent, and the temperature of the raw material itself begins to rise. In the first heating zone, the thermal conductivity of the raw material decreases to some extent, so the temperature of the hot water introduced into the heating plate (6b) is set slightly lower than that in the first heating zone, and The drying process conditions are adjusted so that the heat flux is also somewhat reduced. In this way, the raw material has a moisture content of approximately 90%
The evaporated state is sent from the first heating zone to the subsequent second heating zone.

The raw material introduced into the No. 1 heating zone formed by the third heating plate (6c) has a lower moisture content than the first heating zone and the No. 1 heating zone, and does not cause any swelling phenomenon. It is slowly vacuum dried to the final moisture content.

That is, in the first heating zone, the raw material is dried at a reduced rate, hardening the surface and increasing its own temperature. In this first heating zone, the thermal conductivity of the raw material decreases significantly, so
The temperature of the hot water to be introduced into the heating plate (6c) is set lower than that in the heating zone, and the raw material is subjected to vacuum drying under the effect of a small heat flux and sent to the subsequent cooling zone.

The raw material sent to the cooling zone is passed through the cooling plate (7
), which lowers the temperature of the raw material itself and increases its hardness, thereby obtaining a final dry state suitable for improving the peelability and reducing hygroscopicity of the intermediate product. The intermediate product, that is, the expanded product heated and cooled under vacuum in this manner becomes a porous cake and reaches the end of the endless conveyance path while leaving a trace corresponding to the shape of the supplied liquid on the mesh belt (1). Here, at the end of the endless conveyance path, a fourth
As seen in the figure, a pre-crusher (11) is provided which consists of a hydraulic cylinder mechanism (9) and a shearing blade (10) fixed to a reciprocating piston (38) of the hydraulic cylinder mechanism. Therefore, the intermediate product that has reached the end of the endless conveyance path is primarily pulverized by the vertical movement of the shear blade (10) while protruding from the reversing part of the mesh belt (1), and is transported into the outlet duct (39) at the bottom of the main body into a porous state. Fall as broken pieces of cake. In addition, at the end of the endless conveyance path,
The mesh belt is inverted while rotating from top to bottom (
1) is provided with a scraper (40) for peeling off residual cake adhering to the surface. As illustrated in FIG. 5, the scraper (40) has a shaft (42) rotatably supported by a support bracket (41) fixed to the main body (18) of the vacuum container via a Rulon bearing (49). , 11 An arm (43) extending from the shaft
, a cake scraping blade (46) made of fluororesin fixed to (44) via a blade holding plate (45), the cutting edge of the cake scraping blade (46) is attached to a mesh belt (
1), the arm (43
) and a base plate (47) that supports the proximal end of the support bracket (41). The remaining cake is peeled off from the surface of the mesh belt (1) by pressing it over substantially the entire width of the mesh belt under the bias of the tension spring (48) slightly below the reversal part.

On the other hand, in the main body lower outlet duct (39) located below the pre-crusher (11), as shown in FIG. (52), and a rotary blade (13) made of fluororesin fixed via a rotary blade (13), and a rotary blade (13) that surrounds approximately the lower half of the rotation path of the rotary blade (
A main crusher (15) made of a mesh wire gauze (14) is provided at a predetermined distance from the cutting edge of the main crusher (13). The intermediate product, that is, the crushed pieces of the porous cake, is crushed by the pre-crusher (11).
Mesh Gold II has a predetermined mesh size by rotating the rotary blade (13)! (14) and fall as pulverized granules into a product take-out chamber (17) having a vacuum locking mechanism (1B), where they are stored in a vacuum state. Here, the vacuum locking mechanism (16) has a product removal chamber (17) and a first
air valve (53) and product removal chamber (1).
7) and a second air valve (54) provided at the bottom of the air valve 7), and if necessary, an inert gas supply valve such as nitrogen gas may be installed as a means for preventing moisture absorption or oxidation of the product. It is attached to the product removal chamber (17).

The finely powdered product is passed through the first air valve (53).
) and closing the second air valve (54).
17) When the stored amount of the product reaches a predetermined level, the first airlock valve (53) is closed and the second airlock valve (54) is opened to take out the product. The vacuum state in the chamber (17) is released and the work of taking out the product is started under atmospheric pressure. When this product removal work is completed, the main body (18) of the vacuum container is cleaned, and then the first airlock valve (53) and the second airlock valve (54) are operated to remove the product from the product removal chamber. 17) Restore the interior to a vacuum state, and at the same time start the vacuum generator (28) consisting of the vacuum pump (19), cold trap (20), and chiller unit (21) to restore the main body (18) of the vacuum container. The degree of vacuum inside the chamber is adjusted to a predetermined level necessary for restarting the vacuum drying process. In this state, the vacuum drying/cooling device (
8) Adjust the drying conditions and restart the vacuum drying of the raw materials.

Although the preferred embodiments of the present invention have been described above based on the illustrations of the drawings, the gist of the present invention should not be interpreted as limited by such illustrative explanations, but rather the gist of the present invention should not be construed as limited by such illustrative explanations, but rather the basics specified in the claims. For example, a product removal chamber (
In order to prevent air from outside the system from flowing into the main body (18) of the vacuum container from the product take-out chamber (17) when the capacity of the product take-out chamber (17) is large,
A dedicated second vacuum generator can be provided. Furthermore, a steam heating sterilizer or a cleaning device can be attached to sterilize or clean the inside of the vacuum container main body (18) when changing the product in progress. In addition, when carrying out the present invention, the vacuum pump (19) and the cold trap (20
), chiller unit (21), and vacuum drying/
It is desirable to determine the capacity of the cooling device (8), etc., taking into consideration not only the maintenance of the degree of vacuum and dryness, but also the function of preventing dew condensation within the main body (18) of the vacuum container.

Furthermore, as an application example of the present invention, a multi-stage endless conveyor belt (
1) can also be installed in the main body (1B) of a vacuum container to constitute a vacuum belt dryer.

As can be understood from the above explanation, by employing the device of the present invention, the endless conveyor belt can maintain a stable raw material conveyance posture without meandering or warping over a long period of time. In addition, the material discharge nozzle is used for endless conveyance in the form of a liquid, slurry, or paste.
A thin film that prevents overlapping portions from occurring at the direction change point of one swing of the discharge nozzle on the raw material supplied onto the photoreceptor, and maintains a uniform supply thickness over the entire surface of the endless conveyor belt. Therefore, according to the device of the present invention, uniform heating and cooling can be maintained over the entire area of the J air drying section formed along the moving path of the conveyor belt. Furthermore, in the apparatus of the present invention, a multi-stage crushing device consisting of a pre-crusher and a main crusher is provided at the end of the endless conveying means, and this is combined with a vacuum drying/cooling device. Easy particle size adjustment
(1) It constitutes a granulation device with a simple structure. Tsuru is capable of producing final products with uniform particle size, such as instant coffee, powdered soup, powdered miso, and other granular processed foods, under stable operating conditions.

As is clear from the above description, the vacuum belt dryer according to the present invention is capable of completely eliminating various drawbacks observed in conventional devices, and is capable of improving the quality of processed foods as well as manufacturing costs. It can exhibit a remarkable effect in reducing the amount of water.

[Brief explanation of drawings]

FIG. 1 is a front view taken in section -1, illustrating the overall structure of the device of the present invention. 2 to 6 are explanatory diagrams of the detailed structure of the device of the present invention, and
FIG. 7 illustrates a meandering supply state of raw materials by the apparatus of the present invention, and FIG. 8 shows a meandering arrangement state of raw materials by a conventional apparatus. 1 (1)・−・Endless conveyor belt, (2)・−・
Rotating arm 1, (3) --- nozzle, (4) --- nozzle swing speed> control mechanism, (5) --- raw material supply device, (6) i --- heating plate, (7)・−
Cooling plate, (8)' - Vacuum drying/cooling device, (9) Curved/fluid pressure cylinder; Da mechanism, (10)
- Shearing blade, (11) - Preclara' Shear, (
12) -- Mechanism for preventing meandering and warping of endless conveyance means, (13) -- Rotating blade, (14) -- Mesh wire mesh, (15) -- Main crusher, (16) --
- Vacuum lock mechanism, (17) --- Product removal chamber. Procedural amendment May 8, 1985 1. Indication of the case 1985 Patent layer No. 64711 2. Name of the invention Vacuum belt dryer 3. Person making the amendment Relationship to the case Patent applicant name Name Japan Co., Ltd. Saka Seisakusho 4,
Agent: 550 Address: 1-15-26 Edobori, Nishi-ku, Osaka-shi, Osaka Prefecture, Japan, page 10, line 17-18, insert the following sentence between “taru” and “drive roller” do. ``In addition, in (1), it is desirable to perform surface treatment with a resin such as silicone or polytetrafluoroethylene, in view of the above required characteristics.''

Claims (1)

[Claims] (1) A vacuum belt dryer for vacuum-drying raw materials prepared in liquid, slurry, or paste form and extracting them as granular dry products, which is an endless belt dryer made from knitted or woven fabric made of synthetic fiber yarns. In the movement path of the conveyor belt, from the raw material supply side to the product delivery side, there is a raw material supply device consisting of a rotating arm, a nozzle, and a swing speed control mechanism for the nozzle, and a plurality of heating plates and a single cooling plate. A vacuum drying/cooling device, a pre-crusher consisting of a fluid pressure cylinder mechanism and a shearing blade are sequentially installed, and a mechanism for preventing meandering and warping is attached to the drive device for the endless conveyor belt. A vacuum belt dryer characterized by sequentially disposing a main crusher consisting of a rotating blade and a mesh wire mesh arranged so as to surround the circumference approximately halfway around the rotating blade, and a product take-out chamber having a vacuum locking mechanism below. Machine.