JPH0449918Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a vacuum belt dryer.

BACKGROUND ART In recent years, vacuum dryers have been used as manufacturing equipment for pharmaceuticals and food materials, especially as drying processing equipment for them. For example, many types of processed food materials and instant foods are on the market as people's diets become more diverse.In the field of food processing,
In order to maintain the solubility and ready-to-ready properties at a specified level when consumers use the product as a cooking ingredient, and to give the final product resiliency without deterioration of quality or deterioration of ingredients, various conventional methods are used. Pressure drying equipment and vacuum drying equipment are used. Among such drying devices, attention has been paid to the fact that it is relatively easy to maintain the solubility of processed food materials used 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 problems with the solubility and quality of processed food materials due to restrictions on drying temperature. The retention performance and the prevention performance of component changes are somewhat inferior, and the latter is accompanied by problems such as a complicated structure of the device and a rise in drying costs due to the adoption of a freezing/sublimation process. Therefore, there has been a demand for the development of a vacuum belt dryer as a means of solving the practical problems observed in the above-mentioned spray dryers and freeze dryers.

A vacuum belt dryer has a constant rate drying zone, a decreasing rate drying zone, and a cooling zone sequentially arranged in a vacuum container, and a belt conveyor for conveying materials to be dried, such as processed food materials, to these zones. A device is provided, and the processed food material is distributed and supplied in a liquid, slurry, or paste form, and the processed food material is sequentially introduced into the constant rate drying zone, the decreasing rate drying zone, and the cooling zone by rotation of this endless conveyor belt, It is configured to perform vacuum drying under drying conditions at a relatively low temperature. At this time, the processed food material placed in the form of a thin film on the endless conveyor belt undergoes a violent evaporation phenomenon of the moisture contained inside, causing the processed food material to expand and create a number of ventilation holes inside. The product is formed and sent as a porous intermediate product to a crusher provided at the end of the rotation path of the endless conveyor belt.
As can be seen from the above description, vacuum belt dryers have been evaluated for their usefulness as an alternative technology to conventional spray dryers and freeze dryers. Focusing on this point, the applicant of the present invention previously proposed
Improvements to vacuum belt dryers have been proposed in publications such as 223480.

Problems that the invention aims to solve Vacuum belt dryers are significantly superior to conventional spray dryers and freeze dryers in terms of ease of maintaining product quality, mechanism for preventing changes in components, and ability to reduce drying costs. Although it can exhibit superior performance, there are many points that require further structural and functional improvements in order to respond to the diversification of food materials, pharmaceutical materials, etc. to be subjected to drying processing. for example,
When the material to be dried placed on the endless conveyor belt is sent out from the cooling zone in an undried state and reaches the crusher, the undried material, which contains excess moisture and has become a lump, falls under its own weight without being crushed and is transferred to the crusher. The mesh becomes clogged, making it impossible for the vacuum belt dryer to continue operating. Undried material stuck in the mesh of the crusher must be removed. This hinders the continuous operation of the vacuum drying process and significantly reduces productivity. Furthermore, since dried food materials and food materials that are not sufficiently dried are taken out of the vacuum belt dryer in a mixed state without being separated, maintenance of the quality of the final product is also adversely affected.

The main object of the present invention is to provide a vacuum belt dryer with improved sorting function that eliminates the risk of contamination of undried materials into the final product.

Means for Solving the Problems As a means for solving the above problems, the present invention provides a vacuum belt dryer in which a constant rate drying zone, a decreasing rate drying zone, and a cooling zone are sequentially arranged in a vacuum container.
A bypass for discharging defective dried products is placed adjacent to a dried material take-out duct with a crusher provided below the end of the rotation path of the endless conveyor belt, and an upper end of the dried material take-out duct and the bypass for discharging defective dried products. A rocking plate with a drive unit for selectively guiding dried material falling from the terminal end of the endless conveyor belt to either one of the entrances is disposed between the entrances of the drying material take-out duct and the drying material. A sensor for detecting the degree of dryness of the dried material and controlling the drive section of the rocking plate is disposed in the bypass for discharging defective products, and based on the detection result from the sensor, the undried material with a low degree of dryness is removed from the drying state. The purpose of the present invention is to provide a vacuum belt dryer in which the dried products are guided to the entrance of a bypass for discharging defective products, and the dried products with a high degree of dryness are guided to the entrance of the dried product take-out duct.

Function The vacuum-dried products are distributed to the crusher side or the bypass side for discharge outside the system depending on the moisture content, and this prevents deterioration of product quality due to contamination of undried materials and release of vacuum when discharging defective products. Prevents a decrease in operating efficiency of the vacuum belt dryer due to stoppage.

Embodiment FIG. 1 is a vertical cross-sectional view illustrating the overall structure of a vacuum belt dryer according to the present invention, and FIG. 2 is a schematic vertical cross-sectional view illustrating the operating state of the dry matter distribution device. As illustrated in FIG. 1, the inside of the vacuum vessel 1 is maintained at a vacuum level of approximately 10 Torr by means of a cold trap and a vacuum pump 2 during operation. The material to be dried prepared in the form of a liquid, slurry or paste, such as a concentrated liquid of corn soup, is transferred to an endless conveyor belt 4 by a dispersing nozzle 3.
It is uniformly distributed and supplied in the form of a thin film. The vacuum belt dryer is equipped with a hot water generating device 20 consisting of a water tank 17, a pump 18, and a heat exchanger 19. A functioning first heating plate 5a, a second heating plate 5b, and a third heating plate 5c functioning as a reduction rate drying means are sequentially arranged along the moving direction of the endless conveyor belt 4. Furthermore, a cooling plate 6 is provided downstream of the third heating plate 5c for cooling the material to be dried with cold water supplied from the chiller unit 9. In this way, as the endless conveyor belt 4 moves from the dispersion nozzle 3 at a constant speed, it sequentially passes over the first heating plate 5a, the second heating plate 5b, the third heating plate 5c, and the cooling plate 6, Drying treatment is applied. To explain in more detail, the material to be dried is first heated on the first heating plate 5.
It is heated by a, and starts intense water evaporation and expansion, which evaporates about 50 percent of the retained water and adjusts the dry moisture ratio to about 50 percent and the solid content concentration to 50 to 66 percent. In this state, it moves onto the second heating plate 5b. By being heated by the second heating plate 5b, the material to be dried evaporates most of its retained moisture and is transferred onto the subsequent third heating plate 5c as an intermediately dried product with a substantially constant expanded thickness and surface shape. Sent out.
The intermediately dried product sent out from above the second heating plate 5b has a dry moisture ratio of about 40 by constant rate drying.
% and solids concentration between 66 and 95 percent. Thereafter, by decreasing rate drying on the third heating plate 5c, the moisture content of the intermediately dried product is reduced until it reaches a final moisture content of about 10 percent. This reduced rate drying increases the solids concentration to 95 to 97 percent and hardens the surface of the material to be dried. The solidification process is completed by supplying the above-mentioned intermediately dried product onto a cooling plate 6 having a surface temperature of 20 to 10° C. and curing it by lowering the temperature. In this way, the solid content concentration is reduced to approximately 97
The material to be dried, which has been adjusted to the desired percentage, is sent to the end of the rotating path of the endless conveyor belt 4 as a drying format 11 in a porous chamber, and then transferred to a precrusher 7 equipped with reciprocating shear blades mounted on the upper part of the vacuum container 1. This results in primary crushing.

In the device of the present invention, as shown in FIGS. 1 and 2, a dried material take-out duct 10 is provided below the operating area of the pre-crusher 7 and below the terminal end of the endless conveyor belt 4. A bypass 15 for discharging defective dried products is arranged adjacent to the product take-out duct 10. A swing plate 12 driven by a pneumatic actuator 22 is installed at the upper end of the partition plate 16 between the dried product take-out duct 10 and the bypass 15 for discharging defective dried products.
is installed. This rocking plate 12 is capable of swinging in the left and right directions around a hinge part at the lower end, and the final dried product, that is, the porous format 11, which is primarily crushed by the precrusher 7 and falls under its own weight from the end of the endless conveyor belt 4, is , 11' are sorted and guided to a dried material take-out duct 10 or a bypass 15 for discharging defective dried products depending on the moisture content.

Sensors 23 and 24 for detecting the degree of dryness of the porous format are disposed within the dried material take-out duct 10 and the bypass 15 for discharging defective dried products. The detection results of the sensors 23 and 24 are input to the control device 25, and when the sensor 24 detects a degree of dryness lower than a predetermined value (insufficient dryness), the swing plate 12 swings to the position shown in Fig. 2 A. However, when the sensor 23 detects a degree of dryness higher than a predetermined value (when the dryness is sufficient), the swing plate 12 is configured to swing to the position shown in FIG. 2B. As a result, the sufficiently dried porous format 11 is guided to the dried material take-out duct 10, and the insufficiently dried porous format 11' is guided to the bypass 15 for discharging defective dried products.

A crusher 14 consisting of a rotating blade and a wire mesh is provided at the upper part of the dry matter removal duct 10.
A crusher 14 pulverizes the porous format 11 which has been sufficiently dried and primarily pulverized, and sends it to a product tank 13 as a granular or fine granular product.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified in various ways. For example, the swing plate 12 can be driven by various drive methods other than the pneumatic actuator 22. It is also possible to manually operate the swing plate 12 by visually observing the degree of drying of the dried material in the vacuum container through an inspection window of the vacuum container.

Effects of the Invention By using the device of the present invention, vacuum-dried products can be separated according to their moisture content during operation of a vacuum belt dryer. Therefore, it is effectively possible to avoid deterioration in the quality of the product due to the contamination of defective drying materials and a decrease in the productivity of the vacuum belt dryer due to vacuum release and stoppage when discharging defective drying products.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of the vacuum belt dryer, Figure 2 A is a schematic vertical cross-sectional view of the dry matter sorting device when discharging defective dried products, and B is a schematic cross-sectional view of the dry matter sorting device when taking out dried products. It is a diagram. 1... Vacuum container, 4... Endless conveyor belt, 10
... Dry material removal duct, 12 ... Rocking plate, 1
4... Crusher, 15... Bypass for discharging defective dried products, 16... Partition plate, 22... Actuator (drive unit), 23, 24... Sensor for detecting degree of dryness, 25... Control device.

Claims (1)

[Scope of utility model registration request] In a vacuum belt dryer in which a constant rate dryer, a decreasing rate dryer, and a cooling area are sequentially arranged in a vacuum container, a crusher is installed below the end of the rotation path of the endless conveyor belt to dry the dry material. A bypass for discharging defective dried products is placed adjacent to the take-out duct, and between the upper end entrances of the dry product take-out duct and the bypass for discharging defective dried products, the dry products falling from the terminal end of the endless conveyor belt are removed from the entrance. A rocking plate with a drive unit is disposed in the dry matter take-out duct and the bypass for discharging defective dried products, and the dryness of the dry matter is detected and the rocking plate is guided selectively to one of the two directions. A sensor is provided to control the drive unit, and based on the detection results from the sensor, undried items with a low degree of dryness are guided to the entrance of the bypass for discharging defective dried items, and dried items with a high degree of dryness are guided to the entrance of the bypass for discharging defective dried items. A vacuum belt dryer characterized by being guided to the entrance of a take-out duct.