JP2000176435A - Supernatant water discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a float type supernatant water discharge device provided with a bellows type extendable discharge pipe in which the shrinkage toward the inside of the extendable discharge pipe is prevented, there is no fear of preventing circulation of the supernatant water, the expansion toward outside due to the reaction at the time of stopping the circulation and capable of elongating the service life of the expansion discharge pipe. SOLUTION: In the float type supernatant water discharge device provided with the bellows-type extendable discharge pipe 2 connected to a water collecting part and expanding and contracting by the vertical motion of a float 4, the supporting pipe 5 inserted till the length of at least 1/4 of the extendable discharge pipe from the upper end port of the extension discharge pipe 2 is provided. The extendable discharge pipe 2 is mainly the resin or rubber made bellows pipe extending and contracting by the vertical motion of the float 4, and the water collecting trough 3 being the water collecting part is connected at its upper end and a fixed discharge pipe 7 is connected at its lower end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supernatant water discharge device in a water treatment facility such as a batch type sewage treatment tank.

[0002]

2. Description of the Related Art Conventionally, a batch type sewage treatment tank for biologically treating wastewater by repeating aeration, sedimentation solid-liquid separation and supernatant water discharge in a single tank, or a sedimentation tank for separating sludge by natural sedimentation. And the like, the supernatant water discharge device (hereinafter simply referred to as the discharge device)
Is used.

[0003] As the discharging device, a plurality of water collecting portions provided with a discharging valve are fixedly disposed at a predetermined height position in a tank,
In some cases, a fixed discharge device that discharges supernatant water by sequentially controlling the opening and closing of a discharge valve, a pump discharge device that suctions and discharges supernatant water using a pump, and the like are used. There are problems with the ability to follow water level fluctuations and the stability of the sludge interface at the time of discharge, and because of the increase in equipment costs, etc., the float type with the water collecting part floated to a predetermined position near the water surface with a float Discharge devices are also widely used.

[0004] In the above-mentioned float type discharge device, a float which moves up and down following the water level fluctuation in the treatment tank to maintain the clear water overflow port of the water collecting portion at a predetermined position near the water surface is provided in the water collecting portion. An apparatus provided with a bellows-shaped telescopic discharge pipe (hereinafter simply referred to as a telescopic discharge pipe) which is connected to a water collecting part and expands and contracts by vertical movement of a float is widely used. In addition,
Since the expansion / contraction discharge pipe bends vertically and horizontally due to the flow of the liquid in the tank, a guide pipe surrounding the outer periphery of the expansion / contraction section of the expansion / contraction discharge pipe, a guide rod set up near the axis of the expansion / contraction discharge pipe, or near the outside, etc. It is supported and the bending movement is regulated.

[0005]

In a conventional float type supernatant water discharging apparatus in a water treatment facility provided with a telescopic discharge pipe, a flexible material is used to form the telescopic discharge pipe in a bellows shape. The inside of the supernatant water flowing from the overflow port of the supernatant water into the telescopic drainage pipe is depressurized and contracted inward by the external water pressure, narrowing the flow passage and impeding the smooth flow of the supernatant water. There is a problem to do. There is also a problem that the life of the telescopic discharge pipe is reduced by repeating the inward contraction and the outward swelling due to the recoil at the time of stopping the flow.

Accordingly, the present invention has a simple structure, is easy to maintain, prevents shrinkage of the bellows-shaped telescopic discharge tube to the inside, does not obstruct the flow of the supernatant water, and is capable of stopping the flow of the supernatant water. The purpose of the present invention is to provide a float type supernatant water discharge device which can prevent the expansion and contraction of the expansion / contraction pipe from extending outward due to the recoil of the water.

[0007]

The gist of the present invention for achieving the above object is to move up and down in accordance with the water level fluctuation in the treatment tank as described in claim 1, Float in a water treatment facility provided with a float for maintaining the clear water overflow port at a predetermined position near the water surface, and provided with a bellows-shaped telescopic discharge pipe connected to a water collecting part and expanded and contracted by vertical movement of the float.
A supernatant water discharge device, characterized in that a support pipe is inserted therein from the upper end of the telescopic discharge tube to at least １ ／ the length of the telescopic discharge tube.

By providing a support pipe which is inserted from the upper end of the telescopic discharge pipe to at least one-fourth of the length of the telescopic discharge pipe, it is generated inside by the flow of clear water flowing into the telescopic discharge pipe. Contraction to the inside of the bellows-shaped telescopic discharge tube due to the reduced pressure and the water pressure from the outside is regulated by the support tube,
In addition to preventing the possibility of obstructing the flow of supernatant water, it also prevents outward swelling due to recoil at the time of stoppage of flow, and there is no inward shrinkage or outward swelling. Can be extended.

Since the pressure reduction caused by the flow of the supernatant water flowing into the expansion / contraction discharge pipe is greater near the overflow port of the supernatant water, the length of the support pipe is 1/4 or less of the expansion / contraction discharge pipe. When the length of the support pipe is at least 1/4 of the length of the telescopic discharge pipe, the length of the vertical portion of the fixed discharge pipe connected to the lower end of the telescopic discharge pipe is small. Since it is necessary to increase the length of the supernatant water more than necessary, the discharge amount of the supernatant water is reduced, and accordingly, the amount of the supernatant water that remains without being discharged increases.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of one embodiment. Reference numeral 1 denotes a float type supernatant water discharge device in a water treatment facility provided with a bellows-shaped telescopic discharge pipe 2 which expands and contracts by the vertical movement of the float.

The expansion / contraction discharge pipe 2 is a bellows-shaped pipe mainly made of synthetic resin or rubber which expands and contracts by the vertical movement of the float, and a water collecting trough 3 which is a water collecting part is connected to the upper end. A fixed discharge pipe 7 is connected to the lower end, and a plurality of rod-shaped guides 11 that prevent the expandable discharge pipe 2 from bending in the horizontal direction when the expandable discharge pipe 2 expands and contracts are provided on the side of the expandable discharge pipe 2. It is erected.

The other end of the fixed discharge pipe 7 penetrates a side wall of a processing tank (not shown), is connected to a pipe of the next process through a supernatant water discharge control valve, and is connected to a vertical discharge pipe 2. The length is set in consideration of the projecting length of the support pipe 5 from the lower end of the telescopic discharge pipe 2 when the telescopic discharge pipe 2 contracts.

The collecting trough 3 is a tubular body having a rectangular cross section with a rectangular cross section, a supernatant water overflow port 8 is formed at the upper end face, and the telescopic discharge pipe 2 is connected at the lower end. A float valve 6 for opening and closing the supernatant water overflow port 8 is supported and accommodated by a guide rod 12, and a valve seat 13 to which the lower end surface of the float valve 6 abuts protrudes from a lower side wall. I have. The float valve 6 may have a columnar or triangular pyramid shape, but is preferably a long float valve having a trapezoidal vertical cross section in view of the obstruction of the supernatant water overflow port 8 and the smoothness of ascending and descending.

Reference numeral 4 denotes a float supported by an engaging member projecting from the water collecting trough 3 to the outside to maintain the supernatant water overflow port 8 at a predetermined position near the water surface at the water collecting part, and prevents the inflow of scum. A scum baffle 14 is provided. In addition,
The float 4 may be an air-filled steel or synthetic resin tubular body, or may be made of a foamed material such as styrene foam, and may have a cylindrical, cylindrical, spherical or square cylinder, prism, or the like. A cylindrical air-filled float is preferable from the viewpoints of durability, easiness of maintenance, arbitrarily setting the air-filling amount, and buoyancy adjustment. Also, the number of attachments is preferably four, but is not limited.

5 is inserted from the upper end of the telescopic discharge pipe 2,
This is a support pipe which is inserted and inserted at least up to the length of the telescopic discharge pipe, and has a thickness with a slight gap with the inner wall of the telescopic discharge pipe, and is made of steel slightly thinner than the fixed discharge pipe 7. And a cylindrical body made of synthetic resin is appropriately used.

The operation of the supernatant water discharging device according to the embodiment will be described in detail below. To discharge the supernatant water, a supernatant water discharge control valve (not shown) provided on the fixed discharge pipe 7 is opened, so that the supernatant water that has accumulated over the water collection trough 3 and the discharge pipes 2 and 7 flows out due to a head difference. Then, the float valve 6 is pushed down by the pressure decrease in the water collecting trough 3 and the water pressure from the upper part, the supernatant water overflow port 8 is opened, and the supernatant water flows into the water collecting trough 3, and the expansion / contraction discharge pipe is provided. It is discharged out of the tank through 2 and the fixed discharge pipe 7. When the supernatant water flows into the collecting trough 3, there is a possibility that the floating scum may flow in at the same time. The floating scum can be prevented by the scum baffle 14 provided on the float.

Further, since a support pipe is inserted from the upper end of the telescopic discharge pipe 2 to at least a length of 伸縮 of the telescopic discharge pipe 2, the clear water flowing into the telescopic discharge pipe 2 is circulated. The contraction inward of the bellows-shaped telescopic discharge pipe 2 due to the decompression caused inside and the water pressure from the outside is caused by the support pipe 5.
To prevent the possibility of obstructing the flow of supernatant water, and also prevent outward swelling due to recoil at the time of stoppage of flow, and there is no inward shrinkage or outward swelling. 2 can extend the life.

Further, in the above supernatant water discharging operation,
The supernatant water overflow port 8 of the collecting trough 3 is constantly adjusted to a constant water level near the water surface by a float 4 for adjusting the buoyancy. Therefore, it descends following the surface of the water in the tank that descends with the discharge of the supernatant water, and a constant amount of the supernatant water can always be discharged continuously.

The discharge of the supernatant water is stopped by closing the above-mentioned supernatant water discharge control valve so that the collection trough 3 and the discharge pipe 2,
The supernatant water stays for 7 and the float valve 6
Rises into the supernatant water overflow port 8 and can be completely closed. Therefore, even during the aeration operation in the batch type sewage treatment tank, the inflow of sewage to the water collecting section is completely prevented.

In the telescopic discharge pipe 2 caused by the discharge of the supernatant water and the stoppage of the drainage, the plurality of bar-shaped guides 11 provided to prevent the telescopic discharge pipe 2 from bending in the horizontal direction when the telescopic discharge pipe 2 expands and contracts. In addition, the opening and closing control of the supernatant water discharge control valve is appropriately controlled according to the treatment state of the wastewater, and the discharge of the supernatant water and the stop of the discharge are sequentially repeated. However, the control may be performed manually, and a timer or the like may be used. It is also preferable to perform automatic control by the above control device.

[0021]

The supernatant water discharger of the present invention has a simple structure, is easy to maintain, and is of a float type, so that it can follow the water level fluctuation very well. The inflow of sewage can be completely prevented, and furthermore, since the support pipe is provided inside the telescopic discharge pipe, shrinkage to the inside of the bellows-shaped telescopic discharge pipe is prevented, thereby impairing the flow of supernatant water. This eliminates fear and prevents swelling to the outside due to recoil at the time of stoppage of distribution, thereby extending the life of the telescopic discharge tube.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a supernatant water discharge device according to an embodiment of the present invention.

[Explanation of symbols]

 1: supernatant water discharger 2: telescopic discharge pipe 3: water collection trough 4: float 5: support pipe 6: float valve 7: fixed discharge pipe 8: supernatant water overflow port 11: rod guide 12: guide Rod 13: Valve seat 14: Scum baffle

Claims (1)

[Claims] 1. A float which moves up and down following a water level fluctuation in a treatment tank to maintain a supernatant water overflow of a water collecting part at a predetermined position near a water surface, and is connected to the water collecting part. In a float type supernatant water discharge device in a water treatment facility provided with a bellows-shaped telescopic discharge tube which expands and contracts by the vertical movement of the float, at least a quarter of the length of the telescopic discharge tube from the upper end of the telescopic discharge tube. A supernatant water discharge device having a support tube inserted therein.