JPS598180B2 - Sand separation equipment for sewage sedimentation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for recovering sand from sediment that has settled in a sewage settling basin, and also to a device for cleaning and separating sand.

Conventionally, in order to recover sand from a settling basin, the garbage and
A flight conveyor is installed in a trough with horizontal and ascending slopes, and the conveyor is equipped with water and air injection pipes, etc. to separate dust from the sand being transported. The sludge was washed away, the water was drained at the ascending slope of the flight conveyor trough, and the sand was carried out.

However, since sewage sediment contains a large amount of dirt and sludge, and the surface of the sand is covered with organic matter, spewing out water and air in the conveyor trough is insufficient to remove bad odors. The small amount of sand cannot be recovered, and the sand that drains poorly and is surrounded by a film of organic material and has a foul odor is transported out.

As a countermeasure to this problem, a device as shown in FIG. 1 has recently been developed.

The device includes a screen 3 installed in a stirring tank 1, a stirrer 2 installed in front of the screen 3 to form a stirring chamber 1a,
A pump 4 is provided on the rear surface of the screen 3 to form a pump chamber 16.

The pump 4 is connected to a cyclone 6 through a pipe 5, and an overflow pipe 6a and an underflow pipe 6b are connected to the cyclone 6. The overflow pipe 6a is connected to the drain, and the underflow pipe 6b is connected to the tail part of the drain conveyor 7. It has been done.

Next, to explain the operation of the above device, the sediment that has flowed into the stirring chamber 1a is stirred by the agitator 2 together with the dilution water, and the dust and sand in the sediment are dispersed, and the sand that has been incorporated into the fibrous dust is dispersed. minutes are also dispersed into the water.

Among the garbage, sludge, and sand dispersed in the water,
When passing through the screen 3, dust is removed, and sand and sludge flow into the pump chamber 16.

The pump chamber 16 is equipped with a pump 4. Generally, a high-head volute pump is often used for this pump, but since this type of pump has a narrow flow path and is easily clogged with dirt, etc., the screen 30 in the previous stage is used. It is necessary to keep the eye opening small.

The sand and sludge sucked into the pump 4 are
It is sent to the cyclone 6 at high pressure (3 to 10 kβ), and due to the centrifugal effect caused by the strong eddy current, light substances such as sludge flow out to the drain through the overflow pipe 6a, while heavy substances such as sand flow into the underflow pipe 6b. The water flows out to the draining conveyor 7, and is carried out after being drained.

However, in the case of this equipment, if large debris gets mixed into the sand settling, the debris collides with the stirring blades that perform strong mechanical stirring to disperse the debris, sand, and sludge, causing abnormal vibrations and causing the equipment to vibrate. The disadvantage is that the process must be temporarily stopped to remove bulky debris.

The object of the present invention is to eliminate the above-mentioned drawbacks and to provide a device that can continuously recover sand with good drainage and little odor even from settled sand containing bulky waste.

FIG. 2 is an explanatory diagram of a sewage sediment cleaning and separation apparatus showing an embodiment of the present invention.

First, a coarse screen 13 and a fine screen 15 are installed before and after the stirring tank 11, and a water or air injection pipe 12 is installed in front of the coarse screen 13 to form the first stage stirring chamber 11.
constitute a.

An injection pipe 12 having an injection nozzle 12a is provided at the bottom of the first stage stirring chamber 11a.

A mechanical stirrer 14a is installed between the coarse screen 13 and the fine screen 15 to constitute a second stage stirring chamber 1lb.

Further, a pump 16 is installed behind the fine screen 15 to form a pump chamber 11c.

A pipe 17 is provided from the pump 16 to the cyclone 18, and an overflow pipe 18a and an underflow pipe 18b are arranged from the cyclone 18.
A is connected to the drain, and the under 7 row t'l8b is connected to the tail portion 19b of the draining conveyor 19.

Next, the operation will be explained. First, the settled sand flows into the first stage stirring chamber 11a together with the dilution water.

At this time, the waste is composed of settled sand, bulky garbage, dirt, sand, and waste, and the bulky garbage generally consists of solid materials such as wood chips and stone blocks.

In addition, the garbage contains a large amount of fibrous materials such as wood chips and stone blocks, and a considerable amount of sand is included in the garbage.

In the conventional sand washing and separation apparatus shown in Fig. 1, the inflowing settled sand is subjected to strong mechanical stirring to disperse the sand contained in the fibers, so that large debris collides with the stirring blade 2a. This may cause abnormal noises and vibrations.

The function of the first stage stirring tank 11a in FIG.
There is a 1 lb stage agitation tank, which disperses the sand content and is therefore focused on removing bulky debris.

However, when removing bulky debris, it is not desirable to remove attached sludge and sand at the same time.
It is necessary to stir these thoroughly.

In this embodiment, since air or water is injected from the injection nozzle 12a in the first stage stirring tank 11a, a stirring water flow is generated in the tank.

Since the bulky waste includes many stones, concrete lumps, wood chips, etc., the above-mentioned agitation flow is sufficient to disperse the adhesion.

In addition, in order to suspend sand, sludge, dirt, etc. in water,
Since this level of stirring strength is insufficient, it is better to make the bottom of the tank slanted to make it easier to flow into the 1 lb second stage stirring tank. It flows into a two-stage stirring tank 1 lb.

At this time, the sediment consists of garbage, sand, and sludge, but the garbage mainly consists of fibers, and since it contains a large amount of sand and sludge, it must be completely removed. Must be dispersed in water.

Due to the strong stirring of the mechanical stirrer 14 installed in the second-stage stirring tank 1Ib, sand and dirt contained in the fibers are also dispersed in the water. Minutes, sludge, and garbage remain suspended in the water for a long time and do not settle to the bottom of the tank.

In the above state, the fine screen 15 removes dust from the settled sand, and the sand and dust flow into the pump chamber 11c.

Since the screen 15 generally has a strong rectifying effect, the sand separates and rapidly settles within the pump chamber 11c.

Note that in order to send sand to the pump 16, it is also preferable to make the bottom of the tank diagonal and further install an auxiliary agitator 14b.

The process from the pump 16 through the pipe 17 to the cyclone 18 is the same as in the conventional apparatus.

As mentioned above, the present invention divides the stirring tank into two stages, removes foreign debris in the first stage and removes fine dust in the second stage, and provides optimal stirring to each stage, resulting in smoother mixing than in a single tank. The effect of enabling driving can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a conventional device, and FIG. 2 is an explanatory diagram showing an embodiment of the present invention. 11... Stirring tank, 11a... First stage stirring chamber, 11b... Second stage stirring chamber, 12...
... Injection pipe, 13 ... Coarse screen, 14a
... Mechanical stirrer, 15 ... Fine screen, 16 ... Pump.

Claims (1)

[Claims] 1 In equipment for transporting washed sand from a sewage settling basin, a coarse screen on the upstream side and a fine screen on the downstream side are installed in the stirring tank, an injection pipe is installed upstream of the coarse screen, and a jet pipe is installed between the coarse screen and the fine screen. A sand separation device for sewage sedimentation, characterized in that a mechanical agitator is provided, a pump is provided on the downstream side of a fine screen, and a liquid cyclone connected to the pump is provided outside the agitation tank.