JPH073298Y2 - Sludge sedimentation interface detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is directed to a sludge sedimentation interface detector in a wastewater treatment tank,
More specifically, it relates to a sludge settling interface detector using a transmission type optical sensor.

[Background of the Invention] In biological treatment of wastewater, particularly in a treatment method using suspended microbial flocs, it is necessary to completely separate supernatant water from suspended sludge after sludge is settled. In particular, when the purpose is to denitrify as well as to decompose organic matter, a part of sludge is likely to be entrained in the discharge of the supernatant water because the sedimentation speed of sludge is slow.

In order to properly control the discharge of the supernatant water and prevent the sludge from being caught, the sludge sedimentation interface must be accurately detected. The technical idea of detecting a sludge sedimentation interface using a transmissive optical sensor is already known, for example, the sixth
In the known sludge sedimentation interface detector shown in the figure, a transmission type optical sensor in which a light projecting surface 2'a and a light receiving surface 2'b are concentrically opposed to each other at a predetermined interval is lowered from the interface to project and receive light. It seeks the sludge's sedimentation interface by attenuating the transmitted light between the surfaces, or tries to detect the increase of light with the sedimentation of the interface by fixing it at a certain depth.

However, if such a known transmissive optical sensor is used to perform the interface detection action, in the search method, the light emitting / receiving surfaces 2'a, 2'b must be lowered from the interface each time aeration is started. Also, if the fixed position type is used, if the water level in the sewage treatment tank increases or decreases due to the volume of sewage inflow,
Since the increase / decrease change cannot be dealt with immediately, the set positions of the light emitting / receiving surfaces 2'a, 2'b must be changed every time the intermittent aeration is started. In any case, using these known transmissive optical sensors, it is extremely difficult to perform unattended management of batch discharge type intermittent aeration.

As a further problem to be solved, due to sludge and algae attached to the light emitting / receiving surfaces 2'a, 2'b of the optical sensor,
The detection function may be impaired.

[Object of the Invention] The purpose of the present invention is to detect the sludge sedimentation interface properly at a certain depth from the water surface regardless of the increase or decrease of the water level in the sewage treatment tank so that the sludge is not caught in the discharge of the supernatant water. It can be used for automatic time control of intermittent aeration in the sewage treatment tank, and can contribute to unattended management of batch discharge type intermittent aeration. It is an object of the present invention to provide an improved sludge sedimentation interface detector that is not affected by sludge and algae attachment.

[Structure of the Invention] In the sludge sedimentation interface detector according to the present invention, the float that moves up and down according to the increase and decrease of the water level in the wastewater treatment tank is provided with a vertical plane facing each other with a predetermined gap. It is formed so that the water in the tank flows through, and the sensing part of the transmission type optical sensor is arranged so that the light emitting surface and the light receiving surface concentrically face each other at a predetermined interval through the water in the tank. In a sludge sedimentation interface detector configured to detect a change in transmitted light caused by passing through the position where the optical sensor sensing unit is disposed, in a linear or linear position at a position orthogonal to the vertical plane across the gap. Vertically-arranged planar elevating guides are fitted in the gap, and vertical plates movably opposed to the elevating guides are connected to each other by inclined plates, and both side edges of the inclined plates are vertically connected to each other. With a wiper mechanism configured to make sliding contact with each surface None, the vertical plane is configured to be wiped by both side edges of the inclined plate when the float is moved up and down or when the wiper mechanism is moved up and down.

[Embodiment] In the drawings of the embodiment, reference numeral 1 denotes a twin or annular float which moves up and down in the wastewater treatment tank in accordance with the water level, and which are opposed to each other with a vertical plane 1a between them with a gap g in which water in the tank can be interposed. The outer surface of each of the vertical surfaces 1a and 1b is covered with a transparent plate such as glass to form a smooth surface. The light emitting surface 2a of the transmissive optical sensor is embedded in one of the vertical surfaces 1a so as to face the gap g, and the light receiving surface concentrically faces the light emitting surface 2a.
2b is embedded in the other vertical surface 1b, and these emitting and receiving surfaces 2
The a and 2b form a sensing unit of the optical sensor. Then, the float 1 is arranged so that the light emitting / receiving surfaces 2a and 2b forming the sensing portion are located at an arbitrary predetermined depth below the water surface of the tank water.
Set the buoyancy of. 3 is a weight of the buoyancy adjusting surface. 4a, 4
Reference numeral b denotes a linear or planar elevating guide which is vertically installed so as to face each other at a position orthogonal to the vertical planes 1a and 1b. Reference numerals 5a and 5b denote vertical plates fitted in the gap g and movably opposed to the elevating guides 4a and 4b. Reference numeral 6 denotes inclined plates for connecting the vertical plates 5a and 5b. The wiper mechanism 7 is configured by the portions 6a and 6b slidingly contacting the vertical surfaces 1a and 1b, respectively. A sludge drop hole 6h is formed in the lower part of the inclined plate 6. The connection between the vertical plates 5a, 5b and the inclined plate 6 is
It should be formed with an acute angle to enhance the sludge slid-off effect. FIGS. 1A and 1B show an example in which a vertical N-shaped wiper mechanism 7 is constructed by connecting vertical plates 5a and 5b in an oblique manner with inclined plates 6. In FIG. 1 [C], by connecting the vertical plates 5a and 5b with the V-shaped inclined plate 6,
This is an example in which the side M-shaped wiper mechanism 7 is configured. In FIG. 1 [D], the vertical plates 5a and 5b are replaced by the inverted V-shaped inclined plate 6
By connecting with, the side reverse M-shaped wiper mechanism 7
This is an example of the configuration.

In FIGS. 2 [A] [B] and FIG. 3, 8 ... 8 is a cord body that controls the action of the guide rail for moving the float 1 up and down, and 9 ... 9 is engaged with the cord body 8 ... 8. Is an engaging element. The upper end of the wiper 7 fitted in the gap g is suspended by a string body 10a fixed to an external fixed body, and
At the lower end of the wiper 7, a cord body 10b to which a weight 11 having an appropriate weight is attached is suspended. Therefore, when the float 1 moves up and down as the water level in the tank rises and falls, the vertical planes 1a and 1b slide up and down while being wiped by both side edges of the inclined plate 6, so that sludge and algae are projected and received by the optical sensor. It is possible to prevent attachment to the surfaces 2a and 2b.

In FIGS. 4 [A] and [B] and FIG. 5, 12 is a small motor installed above the float 1, and 13 is an extension / contraction operation in the vertical direction by rotation of the small motor 12 via a known straight advance mechanism. The end of the expandable shaft 13 is connected to the upper end of the wiper 7. And telescopic shaft 13
When the extension is performed, the wiper 7 reaches below the position where the sensor projecting / receiving surfaces 2a, 2b are arranged, and when the expansion shaft 13 is shortened, the wiper 7 reaches above the position where the sensor projecting / receiving surfaces 2a, 2b are arranged. Is designed to. Therefore, when the expansion / contraction shaft 13 is expanded / contracted by the rotation of the small motor 12, both side edges 7a, 7b of the inclined plate 7 move up and down in the gap g while slidingly contacting the vertical planes 1a, 1b, and the sensor The dirt and attached substances on the light receiving surfaces 2a and 2b are removed.

In batch discharge type intermittent aeration control, sludge precipitation and supernatant water discharge are performed after the end of intermittent aeration. When the layer depth of the supernatant water is increased to a preset predetermined value by the descending sedimentation interface, a separate supernatant water discharge device is activated,
The operation of the supernatant water discharge device is temporarily stopped when the layer depth of the supernatant water is reduced to a preset predetermined value by the operation of the supernatant water discharge device, and the sludge settling interface is detected to be further lowered and then kept constant. The discharge circuit electrically connected is configured so that the operation stop of the supernatant water discharge device is continued until the layer depth of the supernatant water increases and recovers to a predetermined value over time.

If the electric circuit of the sludge sedimentation interface detector of the present invention is switched from the discharge control circuit to the aeration control circuit, Japanese Patent Application No. 62-319
It can also be used for the automatic time control device for intermittent aeration in No. 83.

[Effects of the device] Since the sludge sedimentation interface detector of the present invention is an elevating type that uses a float, unlike the conventional search system and fixed position type, the sludge settling interface detector will detect The detection action is performed properly at a certain depth, and the supernatant liquid is discharged only when the depth of the supernatant liquid is sufficiently deep and there is no risk of sludge inclusion. In this condition, the discharge will be automatically stopped, and there is the advantage that accidents involving sludge can be prevented and the quality of treated water can be guaranteed.

Further, the wiper 7 removes dirt and adhering substances on the sensor projecting / receiving surfaces 2a and 2b, so that an accurate interface detecting function without malfunction is always maintained. Moreover, since the wiper 7 in the detector of the present invention is constructed such that the vertical plates 5a, 5b are connected by the inclined plate 6 and both side edge portions 6a, 6b thereof slidably contact the vertical surfaces 1a, 1b. It has a great effect of removing sludge.

[Brief description of drawings]

FIG. 1 is a perspective view of a wiper in the sludge sedimentation interface detector of the present invention, where [A] and [B] are N-shaped side surfaces, [C] are M-shaped side surfaces, D]
Shows an example of an inverted M-shaped configuration. FIG. 2 is a vertical sectional side view of an essential part of the detector of the present invention in a case where the wiper mechanism is supported at a fixed position by a separate supporting mechanism, and [A] shows a state when the float is raised,
[B] shows the state when the float is descending. FIG. 3 is a cross sectional plan view of the float in the embodiment of FIG. FIG. 4 is a vertical sectional side view of the main part of the detector of the present invention in the case where the wiper mechanism is separately moved up and down by operating the lifting device. [A] is a state when the wiper is lowered,
[B] shows the state when the wiper is raised. FIG. 5 is a cross-sectional plan view of the float in the embodiment of FIG. FIG. 6 is a side view of a sensing part of a sludge sedimentation interface detector using a known transmission type optical sensor. 1 ... Float, 1a, 1b ... Vertical surface, 2a ... Emitting surface, 2b
...... Light receiving surface, 4a, 4b ...... Lifting guide, 5a, 5b ...... Vertical plate,
6 ... Inclined plate, 6a, 6b ... Both side edges, 6h ... Sludge drop hole, 7 ... Wiper mechanism, g ... Predetermined gap.

Claims (6)

[Scope of utility model registration request] 1. A float (1) which moves up and down in response to an increase or decrease in water level in a sewage treatment tank is provided with vertical faces (1a, 1b) facing each other while maintaining a predetermined gap (g). g) The inside of the tank is formed so as to circulate, and the transmission type optical sensor senses so that the light projecting surface (2a) and the light receiving surface (2b) concentrically face each other at a predetermined interval through the water in the tank. In the sludge sedimentation interface detector configured to detect the change in transmitted light caused by the sludge interface passing through the position where the optical sensor sensing unit is disposed. A linear or planar elevating guide (4a, 4b) is vertically installed so as to face each other at a position orthogonal to the vertical planes (1a, 1b), and fitted in the gap (g) to elevate the guide (4a, 4b). 4b) movably opposed vertical plates (5a, 5b) connected by inclined plates (6), and both side edges (6a, 6b) of the inclined plates (6) are The wiper mechanism (7) is formed by sliding contact with the vertical surfaces (1a, 1b),
The vertical planes (1a, 1b) are configured to be wiped by the side edge portions (6a, 6b) of the inclined plate (6) when the float (1) is moved up and down or the wiper mechanism (7) is moved up and down. Sludge sedimentation interface detector characterized by. 2. The sludge sedimentation interface detection according to claim 1, wherein a sludge drop hole (6h) is formed in a lower portion of the inclined plate (6) which constitutes the wiper mechanism (7). vessel. 3. A side face N-shaped wiper mechanism (7) is constructed by connecting the vertical plates (5a, 5b) in an oblique manner with the inclined plates (6). And the sludge sedimentation interface detector according to item 2. 4. A side face M-shaped or inverted M-shaped wiper mechanism (7) is constructed by connecting vertical plates (5a, 5b) with a V-shaped or inverted V-shaped inclined plate (6). The sludge settling interface detector according to the first or second aspect, which is characterized by being set. 5. The float (1) is supported by a wiper mechanism (7) in the gap (g), which is supported at a fixed position by a separate support mechanism.
The vertical planes (1a, 1b) are slid up and down while being wiped by both side edge portions (6a, 6b) of the inclined plate (6) as the vertical axis moves up and down. The sludge settling interface detector according to the paragraphs 3, 3 and 4. 6. The wiper mechanism (7) in the gap (g) is moved up and down at an appropriate time by the operation of a separate lifting device so that both side edges (6a, 6b) of the inclined plate (6) have vertical planes (1a). The sludge sedimentation interface detector according to the first, second, third or fourth aspect is characterized in that it is configured to slide up and down while rubbing (1b).