JPS6258839B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a preliminary dewatering device for a dehydrator for separating a certain amount of water from raw materials and obtaining a stable water concentration at the inlet hopper of the dehydrator. It is.

[Prior Art] When dewatering fish meal, paper sludge, activated sludge from sewerage, etc., a continuous dehydrator of the screw press type is often used. Figure 2 is a sectional view of the basic structure of a continuous dehydrator. To briefly explain the dewatering process performed in this continuous dehydrator, the screw barrel 2 is formed into a tapered shape with a larger diameter on the discharge section 1 side. , a filter cylinder which is mounted around a freely rotatable shaft 3, around which screw blades 4 are spirally wound with a constant outer diameter, and which has a large number of filter holes perforated around the screw blades 4. 5 is placed. When the slurry-like raw material to be dehydrated is introduced from the hopper 6 into the space surrounded by the filter cylinder 5 and the screw barrel 2, the raw material is sent toward the discharge section 1 as the shaft 3 rotates. It is gradually compressed and dehydrated by the filter cylinder 5.

When feeding raw materials to such a continuous dehydrator, if the water concentration is stable, dewatering can be performed efficiently, but if the raw materials have varying water concentrations, the dewatering efficiency will decrease. For this reason, it is preferable to preliminarily make the water concentration as constant as possible for raw materials whose water concentration is not stable before being fed to the dehydrator. Conventionally, in order to eliminate this variation in water concentration, it has been known to supply raw materials to a continuous dehydrator through a preliminary dehydrator such as a rotating sieve or drum screen, but such equipment is large-scale. , a large amount of expense and effort must be spent on installation area, installation costs, and maintenance after installation.

[Object of the Invention] The object of the present invention is to provide a dehydrator that eliminates the disadvantage of requiring large-scale equipment as described above and makes it possible to supply raw materials with a stable moisture concentration to the dehydrator using simple equipment. Our purpose is to provide a preliminary dehydration device.

[Summary of the invention] The gist of the present invention for achieving the above object is as follows:
A plate-shaped filtration screen that divides the inside of the hopper into first and second compartments is provided with its fulcrum at the lower part of the hopper so that it can be tilted in only one direction, and the tilting direction inside the hopper is This is a preliminary dewatering device for a dehydrator, characterized in that a raw material supply port is provided in a first compartment on the side, and a drain hole is provided in a second compartment on the opposite side.

[Embodiments of the Invention] The present invention will be explained in detail based on the embodiment shown in FIG. Note that the same reference numerals as in FIG. 2 indicate the same members.

FIG. 1 is a cross-sectional view of an inlet hopper 10 of a continuous dehydrator. The wall surface of this hopper 10 has a rectangular cross-section, and a filtration screen 12 having a certain weight is set at the lower part of one wall surface as a fulcrum 11. It is constructed so that it can freely tilt within the hopper 10 due to its own weight. A stopper 13 is provided on the top of the hopper 10, and the screen 12 can be tilted from a vertical direction along the wall surface to an angle at which it comes into contact with the stopper 13. This screen 12 has a large number of small holes drilled into, for example, an iron plate. The inside of the hopper 10 is divided into two compartments by a screen 12, and a raw material supply port 14 is provided in the compartment leading to the screw barrel 2, and a drain hole 15 is provided in the wall surface of the compartment on the opposite side. It is being Furthermore, to detect the raw material level,
For example, the electrodes 16a, 16b, 16c are connected to the hopper 10.
These electrodes 1
According to the raw material level signal from 6, the raw material supply port 1
The raw material S is fed into the hopper 10 via the hopper 4.

The raw material S is supplied into the hopper 10 from the supply port 14, separated into a filtrate and a concentrate by the screen 12, and when the liquid level reaches the drain hole 15, the filtrate is discharged to the outside. When there is almost no raw material S in the hopper 10, the screen 12 is in a position where it contacts the stopper 13, and water oozes out from the raw material S through the screen 12 and is discharged from the drain hole 15. Supply port 1
Due to the pressure of the raw material S fed from 4, the pressure applied to the screen 12 also increases, so that the free end of the screen 12 is gradually pushed and moved from the original position of the stopper 13, and the raw material S enters sufficiently and the raw material level rises. This will cause it to stand up almost vertically.

The pressure of the raw material S applied to the screen 12 is canceled out as the screen 12 moves, and the pressure of the raw material S applied to the screen 12 is
The second clogging phenomenon is prevented from occurring. The screen 12 causes the raw material S to be concentrated, and the filtrate is extracted and discharged from the drain hole 15, and the raw material S
As the raw material level decreases as the screen 12 is delivered by the screw blade 4, the screen 12 begins to tilt due to its own weight. At this time, a portion of the filter residue adhering to the screen 12 falls off as the screen 12 tilts. When the concentration of the raw material S progresses and the liquid level falls, the raw material S is supplied again from the raw material supply port 14 and the concentration action is repeated. At this time, there is almost no filter cake attached to the screen 12, so
The filtration action of the screen works effectively to smoothly separate the filtrate and concentrate, resulting in a stable water concentration of the raw material S.

Assuming that the screen 12 is tilted and fixed, as the raw material S is supplied, the pressure of the raw material S is concentrated on the screen 12, and the screen 12
Raw materials near , quickly form a sieve layer,
This filter slag layer bites into the small holes of the screen 12 and the filtration effect gradually deteriorates. In this state, only part of the raw material S near the screen 12 is concentrated, and the raw material inside is not concentrated at all. Therefore, the screen 12 becomes a mere partition plate, and the volume of the hopper 10 becomes narrower by the section partitioned by the screen 12, and the hopper 1 of the raw material S
The residence time in the hopper 10 is also short, and the dehydration processing capacity in the hopper 10 is significantly reduced. Further, the clogging of the screen 12 increases, and even if the screen 12 is inclined, if it is fixed, the filter residue will not fall off naturally, so a cleaning device or the like must be provided as ancillary equipment.

Although the screen is tilted by its own weight, it may be tilted automatically using a drive mechanism according to changes in the level of the raw material S. Further, the raw material supply port 14 is not provided on the side wall of the hopper 10, but is placed above the hopper 10, and the raw material supply port 14 is
You may also drop it. Furthermore, although the above-described embodiment has been described as a preliminary dewatering device for a dehydrator attached to a screw press type continuous dehydrator, it goes without saying that the present invention can also be used in other types of dehydrators.

[Effects of the Invention] As explained above, the preliminary dewatering device of the dehydrator according to the present invention has a filtration screen that is tilted in the hopper, so that it has a stable moisture concentration without requiring large-scale equipment. raw materials can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a preliminary dewatering device of a dehydrator according to the present invention, and FIG. 2 is a block diagram of a conventional continuous dehydrator. Code 2 is the screw body, 4 is the screw blade, 10
is the hopper, 11 is the fulcrum, 12 is the screen, 13
is a stopper, 14 is a raw material supply port, 15 is a drain hole,
16 is an electrode.

Claims (1)

[Scope of Claims] 1. A plate-shaped filtration screen that divides the inside of the hopper into first and second compartments is provided with its fulcrum at the lower part of the hopper so that it can be tilted in only one direction. A preliminary dewatering device for a dehydrator, characterized in that a raw material supply port is provided in a first compartment on the tilting direction side of the hopper, and a drain hole is provided in a second compartment on the opposite side. 2. The preliminary dewatering device for a dehydrator according to claim 1, wherein the filtration screen is tilted by its own weight.