JPH08243319A - Screen device - Google Patents

Abstract

PURPOSE: To provide a screen device by which sand palm deposit in sludge are effectively removed while continuously removing highly viscous sediment. CONSTITUTION: On the outer periphery of a cylindrical screen 4, a spiral scraper 6 is freely, relatively rotatably installed coaxially with the screen 4 to forcibly scrape off the sediment on the surface of the screen 4. Filtrate is taken out from a discharge port 5 for the filtered sludge in the lower part of the screen 4, and sand palm deposit are taken out from a discharge port 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a screen device used in a sludge treatment plant or the like.

[0002]

2. Description of the Related Art For example, in a sludge treatment plant that discharges water from a water purification plant, sludge having a high solid content is sent to a pressure dehydrator with a single screw pump for dehydration. Since a large amount of residue is contained, there is a problem that the pump life is extremely shortened. For this reason, it is necessary to remove sandy residue in advance at the front stage of the pump.

Therefore, a vibrating screen or a screen device has been conventionally used. However, since the deposits on the screen and screen surface are highly viscous and have a large amount of fibrous material, these conventional devices cause clogging in a short time if the openings are such that sand can be removed, and operation can be continued. Disappear. Further, although a flat type scraper has been conventionally attached to the screen device, this scraper also cannot sufficiently remove highly viscous deposits, and there is a problem that continuous operation for a long time cannot be performed. .

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and can effectively remove sand and residue in sludge, and continuously removes highly viscous deposits. The present invention was made in order to provide a screen device capable of preventing clogging.

[0005]

The screen device of the present invention, which has been made to solve the above problems, is configured such that a spiral scraper is coaxially rotated relative to a screen on an outer circumference or an inner circumference of a cylindrical screen. It is characterized by being provided freely.

[0006]

The screen device of the present invention supplies sludge to a cylindrical screen and takes out the filtered sludge from the inside or the outside thereof. However, sand or residue in the sludge accumulates on the filtering surface of the screen. Is the same as the conventional one. However, since a spiral scraper is provided on the filter side of this screen so that it can rotate relative to the screen coaxially, rotating the scraper or screen forcibly scrapes the deposit on the screen filter downward. It is dropped and discharged to the outside. Moreover, since this scraping work can be continuously performed during operation, it is possible to operate the screen device for a long period of time without causing clogging.

[0007]

The present invention will now be described in more detail with reference to the illustrated embodiments. In this embodiment, the sludge is supplied from the outside of the screen and the filtered sludge is taken out from the inside thereof. In FIG. 1, 1 is a casing, 2 is a sludge introduction port provided in the upper part thereof, and 3 is a sand sludge residue discharge port provided in the lower part thereof. Inside the casing 1, a cylindrical screen 4 is provided. In this embodiment the screen 4 is fixed to the bottom of the casing 1,
A discharge port 5 for filtering sludge is provided at the lower end of the screen 4. As the screen 4, for example, a stainless plate having a horizontally long slit having a width of about 0.5 mm is used.

A spiral scraper 6 is provided on the outer periphery of the cylindrical screen 4. In this embodiment, the scraper 6 forms one continuous thread,
Its inner surface is in contact with the outer peripheral surface of the cylindrical screen 4. The upper part of the scraper 6 is connected to an upper support plate 8 by a rod 7. By rotating the upper support plate 8 with a rotary shaft 9 provided on the upper part of the casing 1, the scraper 6 is rotated. . The lower end of the rod 7 is attached to a lower support plate 11 provided with a roller 10 to smoothly rotate the scraper 6 while the roller 10 rolls along the outer peripheral surface of the screen 4.

When the scraper 6 is rotated, the deposit on the outer peripheral surface of the screen 4 is forcibly scraped by the inner surface of the scraper 6. Therefore, the scraper 6 is rotated in such a direction that the deposits attached to the outer peripheral surface of the screen 4 can be scraped downward. As a result, the deposits are collected on the inclined bottom surface 12 of the casing 1 and taken out from the sand and palm residue outlet 3 to the outside.

In this embodiment, the scraper 6 is a single-thread continuous thread, but it may be a 2- or 3-thread multiple thread or a non-continuous thread depending on the property of sludge. When the discontinuous screw is used, a notch is formed between the scrapers 6, so that the edge portion can be expected to have an effect of scraping off the deposit. Further, although the screen 4 is fixed and the scraper 6 is rotated in this embodiment, it is also possible to rotate the screen 4 in reverse.

The usage of the screen device of this embodiment will be described as follows. First, sludge discharged from the water purification plant and having a high solid content is supplied from the sludge introduction port 2 into the casing 1. The sludge is separated from this sludge by the screen 4, and the filtered sludge is taken out from the outlet 5 of the filtered sludge at the lower end of the screen 4. In addition, sandy residue with a large particle size contained in the sludge settles and settles on the bottom of the casing 1.

If such filtration is continued, as described above, the sand and debris adheres to the outer surface of the screen 4 as a highly viscous deposit, which easily causes clogging. Therefore, when the scraper 6 is rotated at an appropriate timing, the deposit adhered to the outer surface of the screen 4 is forcibly scraped down toward the lower part of the casing 1 and is taken out from the sand and dust residue discharge port 3 to the outside. Be done. As a result, the clogging of the screen 4 is eliminated, and the screen device can be continuously operated for a long period of time. It is also possible to operate the screen device while constantly rotating the scraper 6.

In this embodiment, a backwash water supply pipe 13 is provided inside the screen 4. This backwash water supply pipe
13 is a nozzle that rotates together with the rotary shaft 9 and projects laterally
The screen 4 can be backwashed by ejecting backwash water from 14. However, this backwashing means can be omitted.

[0014]

As described above, the screen device of the present invention can effectively remove sand and residue in sludge, and continuously remove highly viscous deposits adhering to the screen surface. Since it can be removed to prevent clogging, it is a valuable screen device particularly suitable for treating sludge discharged from a water purification plant.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a screen device according to an embodiment.

[Explanation of symbols]

1 casing, 2 sludge inlet port, 3 sand and sludge outlet port, 4 screen, 5 filtration sludge outlet port, 6 scraper, 7 rod, 8 upper support plate, 9 rotating shaft, 10
Roller, 11 lower support plate, 12 beveled bottom, 13 backwash water supply pipe, 14 nozzle

Claims (2)

[Claims] 1. A screen device, wherein a spiral scraper is provided on the outer circumference or inner circumference of a cylindrical screen so as to be rotatable relative to the screen coaxially. 2. The screen device according to claim 1, wherein the spiral scraper scrapes down deposits attached to the outer peripheral surface or the inner peripheral surface of the screen.