JPS60256346A - Method of drying tea leaf - Google Patents

Abstract

PURPOSE:To dry uniformly tea leaves even if there is variability in particle size and form of tea leaves, by placing tea leaves of raw material on a drying stand, irradiating them with radiation energy from above while vibrating them vertically. CONSTITUTION:The heating element 1 to irradiate radiation energy such as microwave, far infrared rays, etc. towards the tray 2 are set above the tray 2 vibrating vertically, tea leaves of raw material in a proper thickness are placed on the tray 2, and they are vibrated vertically and irradiated with radiation energy. The tray consists of a trough conveyor, and intermittently vibrated by the use of a timer, etc. The bottom face 3 of the tray or trough conveyor is made of the air-permeable plate 5, and from it air flow at a proper temperature is blown up. Consequently, the tea leaves can be almost uniformly dried even if there is variability in particle size and form of tea leaves, and, especially when the trough conveyor is used,a continuous operation is made possible by stopping the conveyor intermittently.

Description

Detailed Description of the Invention The present invention relates to a method for drying tea leaves using radiant energy such as microwaves and far infrared rays as a heat source, and in particular, tea leaves are placed on a drying table, vibrated up and down, and radiant energy is applied from above. It is characterized by irradiating energy.

The green tea manufacturing process is divided into a rough tea process and a finishing process.

The aracha process involves processing the raw tea picked from the tea gardens to the final stage, including drying, pasteurization, sieving, and combining. In the finishing process, the drying process is the most important, and the quality of the drying directly affects the taste and aroma of the green tea product. Traditionally, tea leaves were dried by hot air drying.

This uses a dryer equipped with several shelves or tray conveyors in the drying room, and since hot air is used as the drying medium, the dryer has the advantage of a simple structure and low fuel consumption. However, on the other hand, tea confectionery has the disadvantage that its quality deteriorates because it loses some of the flavor and aroma characteristic of green tea along with the moisture it contains.

By the way, it is known that when tea leaves are dried using radiant energy such as far infrared rays or microwaves, the tea confectionery loses less flavor and aroma, making it much more flavorful than those dried with hot air. . For this reason, attempts have been made to develop dryers that use these energies as heat sources.

However, the area of the source of the above-mentioned traveling energy is much smaller than the effective area of the trays and conveyors of practical dryers, and the strength of this energy is inversely proportional to the square of the distance from the source. It is not possible to irradiate energy with the same intensity evenly to the effective surface of the shelves, etc., and since the tea confectionery is placed on the shelves VCg with a predetermined thickness, there is a difference between what is on the top surface and what is on the bottom layer. The violet that irradiates energy is different between the two. the result,
The degree of dryness of tea confectionery tends to be quite uneven, and as a result, the green tea product cannot be of satisfactory quality.

As a measure to solve this problem, rotary drum dryers have been tried in the past. This is a drying chamber with a rotating drum equipped with a far-infrared heater, and since the tea leaves are stirred inside the drum, everything receives the same amount of infrared rays. , the macroscopic drying unevenness mentioned above disappears. However, for individual tea leaves, uneven drying still occurs even with this method. In other words, as mentioned above, raw tea leaves are made of different materials, and they also have different shapes, such as curling into needles or small flakes. If the same amount of energy is applied to all of the areas, the degree of dryness will inevitably differ.

As mentioned above, the present invention takes into consideration the fact that individual tea confections have different shapes and materials, and therefore their apparent specific gravity and weight differ by several times or more. The aim is to eliminate uneven dryness and obtain earthy green tea.

The present invention will be specifically explained below.

The present invention provides vertical vibration to tea leaves and
The dryer is equipped with trays for fine imaging on the top and bottom, and a heating element that emits microwave or far-infrared radiation energy is installed above the tray. To dry the ingredient tea confectionery using this dryer, place a predetermined amount of the ingredient confectionery on the tray,
The tray is vibrated up and down, and this vibration is transmitted to the material tea confectionery, causing it to vibrate up and down, and radiant energy is irradiated to the confectionery material. In other words, since the tea confections are turned upside down and stirred together in this way, the top and bottom surfaces of each confection will receive the same amount of heat irradiation, and the confections will receive the same amount of heat irradiation. The overlap is resolved, the difference between the upper layer and the upper and lower layers is eliminated, and uneven drying is eliminated. Particularly in this case, it is important that the number of layers of tea confectionery overlap on the tray. That is, tea confectionery is a collection of products of different materials, shapes, and dimensions, and there are considerable differences among them. Therefore, each tea confectionery rises to a different height due to the vibration, so a particle size gradient occurs vertically on the tray.

Of course, in this case, the larger and heavier tea leaves become the soil layer, and the lighter, flaky ones become the lower layer, so the larger and heavier the tea leaves, the more irradiation will be received with probability.

As a result, the drying unevenness between each tea cake has become even more uneven,
This results in high-quality green tea.

The figure shows an example in which the drying work can be performed continuously.The tray is used as a trough conveyor, and the entire bottom of the tray is used as a ventilation plate to blow air at the appropriate temperature onto the tea cakes. It is something.

In the figure, numeral 1 is a heating element, and 2 is a trough conveyor. The heating element 1 is a heat source that emits radiant energy such as microwaves and far infrared rays, and the trough conveyor 2 is similar to a normal conveyor in this building, and is equipped with a vibration device (not shown) to move the tea cakes up and down. This gives a tendency to vibrate and move it to the left in the figure.

The bottom surface 3 of the trough conveyor 2 is formed using a ventilation plate, and a duct 4 is attached to the bottom surface 3 of the trough conveyor 2, and an air blower 4 is connected to the duct so as to blow an appropriate hot air onto the bottom surface 3. A perforated plate or a mesh can be used as the ventilation plate, and the figure shows as an example a large number of bent plates bent in an F-shape stacked one on top of the other with appropriate distances between their edges. Since the slit 5 for blowing out air is oriented sideways, even if the tea confectionery is mixed with powder, it will not fall down through the slit, and the air blown out has the effect of moving the confectionery forward. Because of this, it is possible to reliably advance even tea confections that are extremely minute and hardly move only by vibration.

Next, the procedure for drying tea confections using this trough conveyor will be explained. From heating element 1) is the trough °′
``C@ radiant heat 2 is irradiated towards the trough conveyor 2.The blower 4 is driven as necessary to blow up air at an appropriate temperature from the ventilation plate, and the tea leaves are quantitatively delivered to the starting end of the trough conveyor 2. The trough conveyor 2 is then intermittently vibrated. As in the case of tray drying described above, the tea confectionery is turned upside down by the vibration, stirred and mixed with each other, and then moved toward the rear end of the conveyor. Then, when the vibration of the conveyor 2 is stopped, the tea remains on the conveyor and is dried by receiving radiant heat from the heating element 1.Of course, in this case, if the wind is blown up from the bottom surface 3 of the trough conveyor 2, the tea leaves will be Since the steam generated and surrounding the tea confectionery is not immediately removed by this wind, the drying speed of the confectionery is increased accordingly, and if this wind is hot air, the speed is further increased.

By the way, the purpose of this method is to stop the photographing of the trough conveyor 2 intermittently by setting a timer or the like, for example. This causes the trough conveyor 2 to vibrate. With this method, it takes several tens of seconds to several minutes to move a tea confection from its starting end to its rear end, whereas it takes several minutes to several tens of minutes to dry tea leaves. Since there is a large difference between the two, by stopping the vibration of the trough conveyor 2 and stopping its movement, the residence time of the tea and confectionery is extended and an appropriate drying time is obtained.

In this case, the larger and heavier the tea confectionery, the faster the moving speed and the shorter the residence time on the conveyor. If the tea leaves are opened in the direction of movement of the tea leaves, the lighter the tea leaves, the stronger the tendency for them to be blown away by the wind blowing out of the tea leaves, so the retention time of all the tea leaves will be balanced.

As detailed above, the present invention is a method of drying tea confections by subjecting them to four vertical vibrations and irradiating them with radiant energy such as microwaves. Especially when a trough conveyor is used, by intermittent stopping of the trough conveyor, connected operation is possible.

[Brief explanation of the drawing]

The figure is a side view schematically showing an embodiment of the present invention. 1; Heat generating body 2; Trough conveyor 3;Bottom 4;Dat 5; Blower Patent applicant agent

Claims (1)

[Scope of Claims] / A heating element for radiant energy such as microwaves and far infrared rays is provided above the tray that vibrates up and down toward the diaphragm, and the material tea and confectionery is placed on the diaphragm to an appropriate thickness. , a tea leaf drying method characterized by applying vertical vibration to the tea leaves and irradiating them with radiant energy. The tea cake drying method according to claim 1, wherein the tray is a trough conveyor, and the tray is intermittently vibrated using a timer or the like. 3. The tea confectionery drying method according to claim 1, characterized in that the bottom surface of the tray or trough conveyor is used as a ventilation plate from which wind at an appropriate temperature is blown up.