JPH03263588A - Drying furnace for powder - Google Patents

Abstract

PURPOSE:To dry fine powders uniformly with a high speed without dispersing them by a method wherein heaters, heating a tray from the upper part and the lower part of the tray, is provided in a furnace body, an air injection pipe is provided above the tray, a powder supplying machine, equipped with a smoothing device, is provided at the inlet part of the furnace body and a powder withdrawal hopper as well as a tray vibrating device, applying the tray with impact and attached to the upper part of the hopper, are provided at the outlet part of the furnace body. CONSTITUTION:Trays 3 are sent into a furnace body 1 sequentially and are heated by heaters 5 and an air injection pipe 6 from both upper and lower surfaces of the trays 3 to dry powders. The drying time of about 60 minutes is enough and it is the speed of two times compared with the drying time of 120 minutes in a batch furnace so far. The powders, charged onto the shallow trays 3 so as to have a uniform thickness, are dried so that the powders in the side of front surface and the powder in the side of rear surface are dried so as to contain the same moisture. The powder, dried in such a manner, are dropped into a powder withdrawal hopper 24 by converting the trays 3 at the outlet part of the furnace body 1 while the powders, adhered to the trays 3, are dropped perfectly by the tray vibrating device 25.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a powder drying oven used for automatically drying powder such as ceramic powder.

(Prior technology) Electrically heated batch furnaces have traditionally been used to dry the moisture in powders such as ceramic powders, but it takes a long time to dry and only the surface layer of the powder is dried. There were drawbacks such as dryness and a tendency to create a moisture imbalance with the powder in the lower layer. It is also conceivable to stir the powder in the oven during drying, but this has not been practical since fine powder tends to scatter around.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and provides a powder drying oven that can uniformly dry fine powder at high speed without scattering it. It has been perfected for the purpose of

(Means for Solving the Problems) The present invention, which has been made to solve the above problems, provides a heater for heating the trays from above and below inside a furnace body to which a large number of powder transfer trays are transferred, and a heater for heating the trays from above and below. An air injection pipe is installed above, and a powder feeder equipped with a leveling device is installed at the inlet of the furnace body, while a hopper for taking out powder and a tray above it are installed at the outlet of the furnace body. The present invention is characterized by being equipped with a tray vibrating device that applies an impact.

(Examples) The present invention will be explained in more detail below using illustrated examples.

In Figure 1, (1) is a tunnel-shaped furnace body, and (2) is an intermittent drive type conveyor that passes through the inside of the furnace body. Powder transfer trays (3) that are long and shallow in the furnace width direction are provided at regular intervals. It is desirable to form ribs (4) on the bottom surface of this tray (3) to expand the heat receiving area and prevent thermal distortion. As shown in Figure 5, the furnace body (1)
Heaters (5), (5) for heating the tray (3) from above and below are provided inside the , and an air injection pipe ( 6
) is provided. The heater (5) is of an infrared radiation type with heating wires embedded inside a ceramic plate, and the atmosphere inside the furnace is maintained at 300''C in the first half of the furnace, and the atmosphere inside the furnace is maintained at 300''C in the second half of the furnace. For example, it is arranged so that the temperature can be maintained at 500°C.In addition, the air injection pipe (6) blows a weak wind with an injection speed of around 3 m/sec toward the tray (3) to accelerate drying. While it took 80 minutes to dry without spraying, drying can be completed in 60 minutes with air spray.This is because the air flow causes convective heat transfer and This is because the flow has the effect of removing a thermal film that obstructs heat transfer.

A powder feeder (8) equipped with a leveling device (7) is provided at the inlet of the furnace body (1). As shown in FIGS. 3 and 4, the powder feeder (8) is equipped with a hopper (9) whose lower surface is an inclined surface, and the upper part of this inclined surface has a hole a.
ω is formed. (11) is a packet that can be brought into close contact with the back surface of this hole 00) as shown in FIG.

The packet (11) is fixed to the tip of the arm side that can swing around the pin 0, and the L-shaped lever 0 that swings around the pin (12a) by the cylinder 04.
The tip of 5) is slidably engaged with this arm 03). For this reason, cylinder 04) is L-shaped lever 05)
When the packet (11) is swung clockwise, the packet (11) assumes an upper position in close contact with the back side of the hole 00) of the hopper (9) as shown in Fig. 4, and the cylinder 04) moves the L-shaped lever 05) counterclockwise. When the packet 01) is swung in the direction shown in FIG. 3, the packet 01) can assume a downward position inverted downward toward the tray (3) as shown in FIG.

06) is a scraping plate provided inside the hopper (4). The scraping plate 06) is supported at the tip of a long arm a'7), and the upper end of this arm 07) is pivotally connected to a cart 09) which can be raised and lowered along a rail 08). This arm surface is supported by the cylinder QΦ,
By adjusting the air pressure acting on this cylinder (to) to a pressure slightly lower than the pressure required to support the weight of the arm 01 and the scraper F1a6), the scraper plate 06
) can be brought into contact with the surface of the pile of powder in the hopper (9) with a very small force, and the powder on the surface of the pile can be scraped together.

Note that (21) is a leveling plate that can slide along a horizontal guide (22), and is driven by a cylinder (23) to flatten the pile of powder that has risen on the top surface of the tray [3]. It is something.

At the outlet of the furnace body (1), as shown in FIG. 5, a hopper (24) for taking out powder is provided, and the powder in the inverted tray (3) is dropped therein. Further, a tray vibrator (25) is provided on the bottom side of the tray (3) to apply an impact to the tray (3) to cause the powder to fall completely.

In addition, as shown in Figure 1, there is a water washing system that sprays water from the underside of the tray (3), which is placed face down on the return side of the conveyor (2), to clean the tray (3)! (26) may also be provided.

(Function) With this configuration, the packet (11) is brought into close contact with the back side of the hole 00) of the hopper (9) as shown in FIG. If the scraping plate aO at the tip of the arm 07) is moved upward from the hopper (9), it will move along the surface of the pile of powder in the hopper (9) with a very light force and remove only the powder on the surface. Scrape it toward you, and then scrape it up along the slope to pass through the upper surface of hole 00). As a result, a certain amount of powder enters the bucket (11) through hole 0, and excess powder flows downward. At this time, since the scraping plate 0ω only lightly scratches the surface of the pile of powder, almost no scattering of the powder occurs even if the powder is fine. Next packet 01
) is reversed by cylinder 04) as shown in Figure 3,
The powder in the packet 01) is supplied in a heaped manner into the tray (3). At the same time, the scraping plate 06) returns to the position indicated by the imaginary line in Figure 1. Next, the tray (3) is moved to the conveyor (2).
The powder is sent to a position below the leveling plate (2I), and the leveling plate (21) moves forward and horizontally from the position shown in FIG. 3 to the position shown in FIG. 4, thereby leveling the powder.

After that, the tray (3) is sent into the furnace body (1) one after another, and is heated from both the upper and lower sides of the tray (3) by the heaters (5), (5) and the air injection pipe (6) described above, and the powder is pulverized. will be dried. As mentioned above, a drying time of about 60 minutes is sufficient, which is twice as fast as the drying time in a conventional batch oven, which was 120 minutes. Further, the powder placed on the shallow tray (3) to a uniform thickness is dried so that both the front and back surfaces have almost the same moisture content. The powder thus dried falls into the powder take-out hopper (24) by reversing the tray (3) at the outlet of the furnace body (1), and also falls into the powder take-out hopper (24).
3) is also completely removed by the tray vibration device (25).

(Effects of the Invention) As explained above, the present invention supplies fine powder to the tray from the inside of the hopper without scattering, and evenly dries it in a short period of time. It can be taken out and is particularly suitable for drying ceramic powder and the like. Therefore, the present invention greatly contributes to the development of industry as a powder drying furnace that solves the problems of the conventional powder drying furnace.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a partially cutaway perspective view of the tray, Fig. 3 is a front view of the inlet section, and Fig. 4 is the same inlet section with a different operating mode. FIG. 5 is a partially cutaway front view of the outlet portion, and FIG. 6 is a partially cutaway side view showing the water washing device. (1): Furnace body, (3): Tray, (5): Heater, (6
): Air injection pipe, (7): Leveling device, (8): Powder feeder, (24): Hopper for taking out powder (25):
) Ray vibration device.

Claims (1)

[Claims] A furnace body (1) to which a large number of powder transfer trays (3) are transferred.
) is equipped with a heater (5) that heats the tray (3) from above and below.
), an air injection pipe (6) is provided above the tray (3), and a powder feeder (8) equipped with a leveling device (7) is provided at the inlet of the furnace body (1). On the other hand, the powder drying method is characterized in that the outlet portion of the furnace body (1) is provided with a hopper (24) for taking out the powder and a tray vibration device (25) that applies an impact to the tray (3) above the hopper (24). Furnace.