JPH0337435Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The invention relates to a vacuum belt dryer, and more specifically, it vacuum-dries raw materials prepared in liquid, slurry, or paste form, and converts them into granular dry products. This invention relates to a liquid supply device for a vacuum belt dryer for taking out liquid.

BACKGROUND ART In recent years, with the diversification of dietary habits, many types of processed food materials and instant foods 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. However, due to the latter's freezing and sublimation processes, the structure becomes complicated and the drying cost increases. At this time, 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 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 a heating zone by means of a 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. , and sent to the crusher as a porous intermediate product. Vacuum belt dryers are thus increasingly being recognized as an alternative technology to conventional spray dryers and freeze dryers.

Problems that the invention aims to solve Vacuum belt dryers have significantly superior performance to known spray dryers and freeze dryers in terms of quality retention, composition change prevention, and drying cost reduction. 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.

For example, when feeding food raw materials prepared in the form of a slurry or paste, in a conventional raw material supply device, the raw material discharge nozzle swings at a substantially constant oscillating speed while moving the raw material onto an endless conveyor belt. As the raw material is placed, a striated portion of the raw material is formed at the direction change point R of the swinging motion, as shown in FIG. In this way, if the raw material placed on the endless conveyor belt while forming a thickened part that is thicker than other parts is subjected to drying treatment under the same heating conditions as other thinner parts, Due to the increase in thickness, the drying effect of the keratinized portion decreases, and problems such as deterioration due to insufficient drying occur. On the other hand, if the heating temperature is set high to suit the above-mentioned keratinous portion, other thinner portions and excessive drying will occur, resulting in problems such as deterioration and deterioration of quality.

The main purpose of the present invention is to solve the above-mentioned problems found in conventional vacuum belt dryers.
An object of the present invention is to provide a vacuum belt dryer having a simple structure and a stable drying function.

Means for Solving the Problems In view of this objective, the present invention provides a liquid supply device 5 disposed on the upper surface of the raw material introduction side of the endless conveyor belt 1 rotatably mounted in the vacuum container 18. In the
The liquid supply device 5 is attached to a drive shaft 2 that is swingably installed vertically.
The first swinging arm 5a is fixed to the lower end of the endless conveyor belt 1 and extends along the moving direction of the endless conveyor belt 1. A second swing arm 5c swings within a predetermined angle range along a plane parallel to the swing surface of the first swing arm 5a, and an upper surface of the second swing arm 5c close to the drive shaft 2. Fixed plate 5
d and are disposed opposite to each other on both sides of the movement path of the endless conveyor belt 1, and contact the contact plate 5d near the swinging of the first swinging arm 5a to move the second swinging arm 5c to the first swinging arm 5c.
A stopper 5e for reversing and tilting in the same direction as the moving direction of the second swinging arm 5a, and a liquid supply nozzle 3 fixed to the tip of the second swinging arm. It is.

Function Raw materials for processed foods prepared in liquid, slurry, or paste form are placed on the endless conveyor belt 1 without forming thickened areas due to the double oscillating motion of the liquid supply device 5. It is supplied in the form of a thin film while creating a meandering trace, and vacuum-dried in the drying/cooling device 8 by the constant speed movement of the endless conveyor belt 1. Thereafter, it is turned into granules by the pre-crusher 11 and the main crusher 15. The product is crushed and taken out of the system in batches from a product take-out chamber 17 having a vacuum lock mechanism 16.

Embodiment FIG. 1 is a partially sectional front view illustrating the overall structure of the device of the present invention, and FIG. 2 is a perspective view of the liquid supply device. FIG. 3 is a plan view illustrating the meandering trace of the raw material fed onto the endless conveyor belt by the apparatus of the present invention.

In FIG. 1, a vacuum generator consisting of a known vacuum pump 19, a cold trap 20, and a chiller unit 21 is disposed in the main body of the vacuum container 18. The vacuum container 18 is constructed so that a degree of vacuum of about 10 Torr can be maintained inside the vacuum container 18 during drying of raw materials.

On the other hand, inside the vacuum container 18, there is a first pipe which has a hot water flow path formed therein, extending along the movement path of the endless conveyor belt 1 from the raw material supply side to the product delivery side.
to third heating plates 6a, 6b, 6c, and a cooling plate 7 having a cooling water flow path formed therein;
are arranged in sequence, and correspondingly, in order to supply hot water and cooling water adjusted to a predetermined temperature to the vacuum drying device 8 constituted by the heating plate and the cooling plate, the vacuum container is Main body 18
includes a known tube or plate heat exchanger 22 which functions as a hot water circulation line heater;
A heating medium and cooling medium circulation device consisting of an expansion tank 23 that promotes circulation of hot water by pressurizing air, and a circulation pump 24 connected to a temperature control circuit (not shown) is connected.

The endless conveyance device basically includes a motor (not shown), a drive roller 26, a driven roller 27,
It also comprises a mesh belt 1 formed by endlessly connecting knitted or woven fabrics of synthetic fiber threads, for example polyester fiber threads, and the mesh belt is wound around the drive roller 26 and the driven roller 27 to form a driving yarn. By doing,
A constant speed conveying device having a conveying speed of 0.05 to 0.5 m/min is formed. 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 peelability 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, an endless conveyor belt is made from a woven fabric of polyester multifilament yarn. is being produced. Note that, in view of the above-mentioned required characteristics, the mesh belt 1 is preferably surface-treated with a resin such as silicone or polytetrafluoroethylene.

The liquid 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 swing speed control device 4 attached to the top surface of the vacuum container 18 as illustrated in FIG. A first swinging arm 5a, which extends downstream along the moving surface of the endless conveyor belt 1, is fixed to the lower end of the swingable drive shaft 2, which extends substantially vertically downward. .
A pivot shaft 5b is fixed to the tip of the first swing arm 5a, oriented substantially vertically, and the pivot shaft 5b has a pivot shaft 5b that is parallel to the swing plane of the first swing arm 5a. Second swinging arm 5 swinging along a plane
c is rotatably fitted and supported via a bearing device (not shown). Further, the upper surface of the second swing arm 5c near the drive shaft 2 is attached approximately parallel to the moving direction of the endless conveyor belt 1 by bolting, screwing, adhesion, welding, or other known fixing means. A plate 5d is attached, and correspondingly stoppers 5e for the contact plate 5d are provided on both sides of the moving path of the endless conveyor belt 1. This stopper 5e is a first swing arm whose amplitude is controlled by two sets of proximity switches 34 and 35 incorporated in the swing speed control device 4 when the first swing arm 5a swings.
Before the swinging arm 5a reaches the direction change point of the swinging motion, the contact plate 5d
is pressed, causing the second swinging arm 5c to generate an additional swinging motion about the pivot shaft 5b.
On the other hand, a liquid supply nozzle 3 is attached to the tip of the second swing arm 5c. In this way, the first swing arm 5a, the second swing arm 5
c and the liquid supply nozzle 3 are swingably supported at a predetermined distance from the upper surface of the endless conveyor belt 1, and the raw material stored in the raw material tank 36 is connected to the raw material tank 36. Supply valve 3
7 and reaches the supply nozzle 3, and remains in a liquid, slurry, or paste state due to the compound swing motion of the first swing arm 5a and the second swing arm 5c, and is transferred to the endless conveyor belt. 1 is placed in a meandering manner.

In the device of the present invention, in order to prevent the occurrence of duplicate supply parts of raw materials as shown in Fig. 4 at the turning points of the meandering liquid supply trace, in other words, parts with increased thickness due to the placement of the serpentine. , under the amplitude control of the liquid supply nozzle 3 by the two sets of proximity switches 34 and 35, the stopper is held for a predetermined time before the first swing arm 5a reaches the direction change point R of the swing motion. 5e is brought into contact with the contact plate 5d, and by this locking operation, the second swing arm 5c
Then, an additional swinging motion is generated around the pivot 5b as the center of rotation. As a result, the liquid supply nozzle 3 has
A first swinging arm 5a whose rotation center is the drive shaft 2.
A synthetic motion of the swinging motion based on the swinging of the second swinging arm 5c and the swinging motion based on the swinging of the second swinging arm 5c about the pivot shaft 5e is applied, and the liquid supply nozzle 3
The raw materials supplied to the endless conveyor belt 1 from
As illustrated in FIG. 3, a locus T bulges out in an arc shape toward the moving direction of the endless conveyor belt 1 (indicated by an arrow with reference symbol F) near the edge of the endless conveyor belt 1. draw Thus, as shown in an enlarged view in FIG. 2a, the liquid supply trace _T1 when the liquid supply nozzle 3 moves from the center in the width direction of the endless conveyor belt 1 toward the edge thereof, and the trace of the endless conveyor belt 1. There is a contact plate ₅ between the liquid supply trace T2 when the liquid supply nozzle 3 moves from the edge toward the center in the width direction.
d and the stopper 5e are brought into contact with each other to maintain an arcuate swollen interval S for preventing sclerosis. Therefore, the raw material supplied from the liquid supply nozzle 3 acquires a meandering form that is spaced apart from each other, with almost no increase in thickness caused by the arrangement of the striations, even in the vicinity of the direction change point of the oscillating motion. I can do it.

On the other hand, in the vacuum drying path formed by the endless conveyor belt, heating plates 6a, 6b, 6 with built-in hot water channels are installed along the lower surface of the mesh belt 1.
A hot water circulation type vacuum drying/cooling device 8 consisting of a cooling plate 7 having a built-in cooling water flow path is disposed.

Although the thin film-like raw material introduced into the I-th heating zone constituted by the first heating plate 6a contains a large amount of moisture, the thermal energy transferred from the high-temperature hot water flowing inside the heating plate 6a The raw material is dried, and moisture begins to evaporate on the surface and inside at the same time, so it is spread out into a film and is subjected to vacuum drying while expanding vigorously. Since this first heating zone is maintained in a constant dry state, the temperature of the raw material itself hardly rises, and the raw material is sent to the rear end of the second heating zone in a state in which approximately half of its retained moisture has been evaporated.

Hot water at a slightly lower temperature than the hot water supplied to the first heating plate 6a is introduced into the second heating plate 6b forming the second heating zone, and the raw materials are subjected to constant rate drying. Most of the retained moisture is evaporated. 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 this 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 heat flux is also lowered. Adjust the drying conditions so that the size becomes somewhat smaller. In this way, the raw material is sent from the first heating zone to the subsequent second heating zone in a state in which approximately 90 percent of the water content has been evaporated.

The raw material introduced into the third heating zone formed by the third heating plate 6c has a lower moisture content than the first heating zone and the third heating zone, and has a final moisture content without swelling phenomenon. It is vacuum dried slowly until the end. That is, in the first heating zone, the raw material is dried at a reduced rate, hardening the surface and raising its own temperature. In this first heating zone, the thermal conductivity of the raw material is significantly reduced, so the heating plate 6
The temperature of the hot water to be introduced into c is set lower,
Under the influence of a small heat flux, the raw material is subjected to vacuum drying and sent to a subsequent cooling zone.

The raw material fed into the cooling zone is cooled by low-temperature water introduced into the cooling plate 7, lowering the temperature of the raw material itself and increasing its hardness, thereby improving the peelability of the intermediate product. as well as obtaining a final drying condition suitable for reducing hygroscopicity. 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 liquid supply on the mesh belt 1. The intermediate product that has reached the end of the endless conveyance path is
The mesh belt 1 protruding from the reversing part is first crushed by the vertical movement of the shearing blades 10 of the pre-crusher 11, and then crushed twice by the main crusher 15 composed of a rotating blade and a mesh wire mesh (both not shown). Next, it will be crushed. The granular product thus obtained is transferred to the vacuum lock mechanism 1.
6 into the product take-out chamber 17, and is taken out of the system in a batch manner.

Effects of the invention As can be understood from the above explanation, by adopting the device of the invention, raw materials for processed foods prepared in liquid, slurry or paste form can be
At the direction change point of the oscillating motion of the liquid supply nozzle, the nozzle is arranged in a meandering manner at a predetermined interval between the forward and return passes, without creating any grooves on the endless conveyor belt, and extends over the entire surface of the endless conveyor belt. As a result, a substantially uniform spreading thickness can be maintained. Therefore, according to the device of the present invention, uniform heating and cooling conditions are maintained throughout the entire vacuum drying section, which significantly improves the quality of processed foods compared to when conventional vacuum drying devices are used. It is possible to achieve the desired effect.

[Brief explanation of the drawing]

Fig. 1 is a partially cross-sectional front view illustrating the overall structure of the device of the present invention, Fig. 2 is a perspective view of the liquid supply device, and Fig. 2a is an enlarged plan view showing the operation of the liquid supply device. . Further, FIGS. 3 and 4 are plan views illustrating the meandering trace form of the raw material supplied onto the endless conveyor belt. 1... Endless conveyor belt, 2... Rotating arm, 3
... Raw material discharge nozzle, 4... Rocking speed control mechanism, 5... Liquid supply device, 18... Vacuum container.

Claims (1)

[Scope of utility model registration request] In a liquid supply device disposed on the upper surface of the raw material introduction side of an endless conveyor belt rotatably mounted in a vacuum container, the liquid supply device is connected to the lower end of a drive shaft vertically disposed in a swingable manner. a first swinging arm fixed to the section and extending along the moving direction of the endless conveyor belt;
a second swinging arm that swings within a predetermined angular range along a plane parallel to the swinging surface of the first swinging arm about a pivot that is vertically installed at the tip of the swinging arm; A contact plate fixed to the upper surface of the second swing arm near the drive shaft and a contact plate arranged opposite to each other on both sides of the moving path of the endless conveyor belt, and attached to the contact plate near the swing end of the first swing arm. Consisting of a stopper that contacts and tilts the second swing arm in the same direction as the first swing arm, and a liquid supply nozzle fixed to the tip of the second swing arm. A liquid supply device for a vacuum belt dryer, which is characterized by: