JP3382926B2 - Cleaning method for air diffuser and air diffuser - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning an air diffuser and an air diffuser, and more particularly to a technique for aerating a mixed solution in a tank in a membrane separation activated sludge method or the like.

[0002]

2. Description of the Related Art Conventionally, in the membrane separation activated sludge method, an air diffuser is arranged below the membrane separator immersed in the aeration tank, and the activated sludge in the aeration tank is removed by the air diffused from the air diffuser. The mixed liquid in the tank containing the liquid is aerated, and the membrane surface of the membrane separation device is washed by the upward flow of the solid-gas mixed phase generated by the rise of the air that has diffused.

As an air diffuser used in this membrane separation activated sludge method, there is, for example, one in which a plurality of holes of about 10 mm in diameter are only opened under a pipe made of vinyl chloride.
With such an air diffuser, it is difficult to completely eliminate the blockage of the pipe due to the property of the activated sludge. If the air diffuser is clogged, it is highly likely that the cake adhering to the membrane surface of the membrane separator will induce clogging between the membranes, so it is necessary to perform not only the air diffuser cleaning work but also the membrane separation device cleaning work. There is.

For this reason, it is necessary to wash the air diffuser during regular maintenance as a preventive measure before the air diffuser is blocked. Generally, the air diffuser is washed once every two weeks, and the pipe of the air diffuser is injected with water to wash the pipe (referred to as “diffusing pipe water washing”).

[0005]

By the way, as described above, in order to wash the diffuser by the diffuser water washing, it is necessary to install a wash water tank and a wash pump as auxiliary equipment. In addition, since it takes time to operate a cleaning pump or the like when cleaning diffuser water, the burden on a maintenance company increases when the operation is performed manually. Therefore, in the worst case, the diffuser water cleaning is not performed. There are situations.

The present invention is intended to solve the above-mentioned problems, and is a method and a diffuser for cleaning an air diffuser capable of structurally suppressing the blockage of the pipe and cleaning the pipe by a simple operation. The purpose is to provide a device.

[0007]

In order to solve the above-mentioned problems, the method for cleaning an air diffuser of the present invention according to claim 1 supplies air from the base end side to a pipe immersed in a tank, In an air diffuser that diffuses air from multiple air outlets provided below the pipe, open the drain valve of the diffuser drain pipe connected to the tip side of the pipe while supplying air to the pipe, and The air to be supplied is exhausted through a diffused drain pipe, the liquid in the tank is reversely flowed into the pipe from the air ejection port to wash the pipe with water, and the pulsation resulting from the pressure change in the pipe is used to intermittently Repeatedly wash with water .

With the above structure, when the drain valve is opened and the air is discharged from the diffused drain pipe, the static pressure in the pipe is lowered and the liquid in the tank flows in from the air jet port. The liquid in the tank that has flowed into the pipe becomes a gas-liquid multiphase flow together with air and flows out from the outlet of the diffuser drain pipe.

At this time, the balance between the liquid phase and the gas phase of the gas-liquid mixed phase flow in the diffuser drain pipe changes depending on the inflow amount of the liquid in the tank, and the liquid phase acts as resistance as the inflow amount increases. It becomes difficult to carry the liquid in the tank by the exhaust air, and the liquid in the tank accumulated in the diffused drain pipe increases and the exhaust is hindered.

Due to the inhibition by the liquid in the tank, pulsation occurs in the pipe and the diffuser drain pipe, and the liquid in the tank that flows into the pipe from the air ejection port is discharged from the diffuser drain pipe and the inside of the diffuser drain pipe. A diffused state in which air is ejected from the air ejection port due to being obstructed by the liquid in the tank that stays in the
By repeating the water washing, the piping can be surely washed, and the washing water tank and washing pump as the conventional accessory equipment are not required, and the burden on the maintenance worker can be reduced.

The air diffuser of the present invention according to claim 2 is
A trunk pipe that is immersed in a tank and placed horizontally, the base end side of which communicates with an air supply source and a plurality of air outlets at the bottom, and one end that communicates with the tip side of the trunk pipe and the other end. There possess a diffuser drain pipe which opens as an exhaust port at a position above the stem pipe, and a drain valve provided in the diffuser drain pipe,
With the air supplied to the trunk pipe, the diffuser of the diffused drain pipe
Open the lube and supply the air supplied to the main pipe to the diffused drain pipe.
Exhausted through the tank, and the liquid in the tank flows backward from the air outlet into the main pipe.
Inserted and washed the main pipe with water, resulting from the pressure change in the main pipe
The water washing is repeated intermittently by utilizing the pulsation generated as a result .

With the above construction, when the air is diffused, air is supplied from the air source at a predetermined pressure while the drain valve is closed, and the trunk pipe is aerated from the base end side and diffused from the lower air ejection port.

At the time of cleaning, the drain valve is opened in a state where the air having a predetermined pressure is supplied from the air source to the main pipe, and the air supplied to the main pipe is passed from the exhaust port to the atmospheric pressure or the predetermined water depth through the diffused drain pipe. Exhaust.

At this time, the exhaust port is opened above the main pipe, and the air outlet is opened below the main pipe.
The main flow of the air in the main pipe goes to the exhaust port with lower resistance, the static pressure in the main pipe decreases, the liquid in the tank flows back into the main pipe from the air outlet, and the liquid in the tank It is discharged from the exhaust port together with air through the diffused drain pipe.

The balance between the liquid phase and the gas phase of the gas-liquid mixed phase flow in the diffuser drain pipe changes depending on the inflow amount of the liquid in the tank, and the liquid phase acts as a resistance as the inflow amount increases, and the exhaust air As a result, it becomes difficult to carry the liquid in the tank, and the liquid in the tank accumulated in the diffused drain pipe increases, which hinders the exhaust.

This inhibition by the liquid in the tank causes pulsation in the main pipe and the diffused drain pipe, and the water washing state in which the liquid in the tank flowing from the air ejection port into the main pipe is discharged from the diffused drain pipe, and the diffused air The diffused state in which the air is ejected from the air ejection port due to the hindrance to the liquid in the tank staying in the drain pipe is repeated intermittently.

The rapid inflow of the liquid in the tank is repeated to effectively clean the sludge adhered to the inside of the main pipe. The sludge adhering to the inside of the main pipe is dried by the air when it diffuses, but the sludge in the tank infiltrates the sludge and promotes the separation of the sludge. Along with this, it is discharged from the exhaust port.

Therefore, without repeating the operation of opening and closing the drain valve by manual operation or automatic operation,
By simple operation of opening the drain valve once, it is possible to repeatedly perform diffuser pipe water cleaning of the air diffuser by utilizing the pulsation caused by the liquid in the tank that flows back into the pipe. As a supplementary facility, a washing water tank and a washing pump are not required, and the burden on maintenance workers can be reduced.

The air diffuser of the present invention according to claim 3 is
A plurality of pipes that are soaked in a tank and arranged horizontally and whose base end side communicates with an air supply source and one end that communicates with the trunk pipe and the other end that opens as an air ejection port below the trunk pipe. the branch pipe, with one end communicating with the distal end of the stem pipe, possess a diffuser drain pipe which other end is opened as an exhaust port at a position above the stem pipe, and a drain valve provided in the air diffuser drain pipe Diffusing drain pipe with air supplied to the main pipe
Open the drain valve of the and diffuse the air supplied to the main pipe.
Evacuate through the drain pipe, and from the air outlet into the branch pipe
Backflow the internal liquid to wash the branch and trunk pipes with water and
Intermittent using pulsation caused by pressure change in piping
The water washing is repeated .

With the above construction, when the air is diffused, the air supplied from the air source at a predetermined pressure is aerated from the base end side to the trunk pipe while the drain valve is closed, and the air is diffused from the air jet port through the branch pipe.

At the time of cleaning, the drain valve is opened in a state where the air having a predetermined pressure is supplied from the air source to the main pipe, and the air supplied to the main pipe is passed from the exhaust port to the atmospheric pressure or the predetermined water depth through the diffused drain pipe. Exhaust.

At this time, the exhaust port opens at the upper position of the main pipe and the air jet port opens at the lower position of the main pipe, so that the main flow of the air in the main pipe is directed to the exhaust port having smaller resistance. , The static pressure in the main pipe decreases and the pressure difference between the air outlet and the main pipe causes the liquid in the tank to flow back into the main pipe through the branch pipe, and the liquid in the tank diffuses with the air. It is discharged from the exhaust port through the drain pipe.

The balance between the liquid phase and the gas phase of the gas-liquid mixed phase flow in the diffuser drain pipe changes depending on the inflow amount of the liquid in the tank, and the liquid phase acts as a resistance as the inflow amount increases, and the exhaust air As a result, it becomes difficult to carry the liquid in the tank, and the liquid in the tank accumulated in the diffused drain pipe increases, which hinders the exhaust.

Pulsation occurs in the main pipe and the diffuser drain pipe due to the inhibition by the liquid in the bath, and the liquid in the bath flowing from the air jet port of the branch pipe into the main pipe is discharged from the diffuser drain pipe. The diffused state in which the air is ejected from the air ejection port due to the hindrance to the tank liquid remaining in the diffused drain pipe is repeated intermittently.

The rapid inflow of the liquid in the tank through the branch pipe is repeatedly generated, so that the sludge adhering to the inside of the branch pipe and the main pipe is effectively washed. The sludge adhering to the inside of the branch pipes and the main pipe is dried by the air when it was diffused, but the liquid in the tank infiltrates the sludge, which promotes the separation of the sludge, and the separated sludge becomes It is discharged from the exhaust port with the exhaust of.

Therefore, without repeating the operation of opening and closing the drain valve by manual operation or automatic operation,
By simple operation of opening the drain valve once, it is possible to repeatedly perform diffuser pipe water cleaning of the air diffuser by utilizing the pulsation caused by the liquid in the tank that flows back into the pipe. As a supplementary facility, a washing water tank and a washing pump are not required, and the burden on maintenance workers can be reduced.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3, an air diffuser 2 and a membrane separator 3 arranged above the air diffuser 2 are immersed in the aeration tank 1. The membrane separation device 3 is not essential for the aeration tank 1, but is used as a means for separating activated sludge in the membrane separation activated sludge method according to the present embodiment.

The membrane separation device 3 can use various types of separation membranes such as an organic flat membrane type, a tube type, and a ceramic type. Here, a plurality of membrane cartridges using organic flat membrane type separation membranes are used. They are arranged in parallel along the vertical direction at a predetermined interval, forming a flow path between adjacent membrane cartridges. Each membrane cartridge communicates with a membrane permeate flow path (not shown), and operates by using the water head (gravity) in the tank or the pump suction pressure as a driving pressure.

The air diffuser 2 has an air diffuser case 4 surrounding the lower region of the membrane separation device 3 and an air diffuser pipe 5 arranged below the air diffuser case 4, and the air diffuser pipe 5 is arranged horizontally. The trunk pipe 6 is a large-diameter pipe having a predetermined diameter, and a plurality of branch pipes 7 are arranged below the trunk pipe 6 and are small-diameter pipes having a predetermined diameter.

The trunk pipe 6 communicates with a blower 8 which is an air supply source at the base end side thereof, and has an air diffusion drain pipe 9 connected to the tip end side thereof. The branch pipe 7 has an inverted T shape, one end of the upper part communicates with the trunk pipe 6, and both ends of the lower part are opened as air outlets 10 below the trunk pipe 6. The diffuser drain pipe 9 is opened at its tip end side above the trunk pipe 6 as an exhaust port 11, and a drain valve 12 is provided in the middle thereof.
In the present embodiment, the exhaust port 11 is opened under the atmospheric pressure above the water surface, but the exhaust port 11 can be arranged below the water surface. The air diffusion case 4 is fixed to the bottom surface of the tank, and the membrane separation device 3 can be moved up and down along a guide 13 provided between the air diffusion case 4 and the tank opening.

The operation of the above structure will be described below. During normal air diffusing operation, the drain valve 12 is in a closed state, and the air supplied from the blower 8 passes through the trunk pipe 6 and from the air ejection port 10 of each branch pipe 7 into the aeration tank 1 mixture liquid. Gushes into. The diffused air aerates the mixed liquid in the tank, and its rise causes an upward flow of the solid-gas mixed phase. This upward flow stirs and mixes the mixture in the tank,
The in-tank mixed liquid is supplied in a cross flow to the flow path between the membrane cartridges of the membrane separation device 3. The membrane separation device 3 filters the in-tank mixed liquid through the filtration membrane of each membrane cartridge, and the upward flow flows as a sweep stream along the membrane surface, and suppresses the cake from adhering to the membrane surface of each membrane cartridge.

During the cleaning operation, the drain valve 12 is opened with the blower 8 supplying air to the trunk pipe 6 at a predetermined pressure, and the air supplied to the trunk pipe 6 is supplied from the exhaust port 11 through the diffused drain pipe 9 to a large amount. Exhaust to atmospheric pressure.

At this time, the exhaust port 11 is opened above the main pipe 6 under atmospheric pressure, and the air ejection port 10 is opened below the main pipe 6, so that the main flow of air in the main pipe 6 is increased. Moves toward an exhaust port having a smaller resistance, and as shown in FIG. 3, the pressure (static pressure) P1 that acts on the main pipe 6 decreases, and the pressure that acts on the air ejection port 10 (determined by the water level in the tank). Due to the pressure difference h from P0, the in-tank mixed liquid flows back into the main pipe 6 through the branch pipe 7.

The mixed liquid in the tank that has flowed in backward is washed with water by washing away the sludge adhering to the insides of the branch pipe 7 and the main pipe 6, and through the diffuser drain pipe 9 and the exhaust port 11 together with the air flowing through the main pipe 6. Is discharged. The sludge adhering to the insides of the branch pipe 7 and the trunk pipe 6 is dried by the air at the time of diffusion, but the separation of the sludge is promoted when the mixed liquid in the tank infiltrates the sludge.

The balance between the liquid phase and the gas phase of the gas-liquid mixed phase flow in the diffuser drain pipe 9 changes depending on the inflow amount of the liquid in the tank,
The liquid phase acts as a resistance as the inflow increases,
It becomes difficult to carry the liquid in the tank by the exhaust air,
Exhaust gas is hindered by an increase in the liquid in the tank that accumulates in the diffused drain pipe 9.

Due to the inhibition by the liquid in the tank, pulsation is generated in the main pipe 6 and the diffused drain pipe 9, and the liquid in the tank flowing from the air jet port 10 into the branch pipe 7 and the main pipe 6 is discharged from the diffused drain pipe 9. The water washing state and the diffused state in which air is jetted from the air jet port 10 by being disturbed by the in-tank liquid accumulated in the diffused drain pipe 9 are repeated intermittently and repeatedly.
Since the rapid inflow of the mixed liquid in the tank into the branch pipe 7 is repeatedly generated, the sludge attached to the inside of the branch pipe 7 can be repeatedly watered without performing the repeated operation of opening and closing the valve manually or by the control device. It can be washed and sludge can be effectively removed.

As shown in FIGS. 4 to 6, the air diffusing pipe 5 can be constituted by the trunk pipe 6 alone, and a plurality of air ejection ports 10 can be formed.
Is provided below the trunk pipe 6. In this configuration, during normal air diffusion operation, the air supplied from the blower 8 is jetted from the air jet port 10 of the trunk pipe 6 into the mixed liquid in the aeration tank 1 with the drain valve 12 closed. During the cleaning operation, the drain valve 12 is opened with the blower 8 supplying air to the main pipe 6 at a predetermined pressure, and the air supplied to the main pipe 6 is passed from the exhaust port 11 to the atmospheric pressure through the diffused drain pipe 9. Exhaust.

At this time, the exhaust port 11 is opened above the main pipe 6 under atmospheric pressure, and the air ejection port 10 is opened below the main pipe 6, so that the main flow of air in the main pipe 6 is increased. Toward the exhaust port 11 having a smaller resistance, the pressure (static pressure) acting on the main pipe 6 decreases, and the air jet port 10
Due to the difference in pressure from the pressure acting on the tank, the in-tank mixed liquid flows back into the trunk pipe 6 through the air ejection port 10. The in-tank mixed liquid that has flowed in reversely is washed with water by washing away the sludge adhering to the inside of the trunk pipe 6, and is discharged from the exhaust port 11 through the diffused drain pipe 9 together with the air flowing through the trunk pipe 6. Other functions and effects are similar to those of the previous embodiment.

It is preferable that the diffuser pipe 5 is formed according to the size of the aeration tank 1 or the size of the membrane separation device 3. For example, as shown in FIG.
8 may be formed in a U shape, and as shown in FIG. 8, the trunk pipe 6 is formed in a zigzag shape, and the air diffusion drain pipe 9 is formed at an intermediate position.
, And both ends may be connected to an air supply source.
Alternatively, the trunk pipe 6 may be formed in a loop shape, the diffused drain pipe 9 may be connected to the intermediate position, and the air supply source may be connected to the opposite electrode position.

[0040]

As described above, according to the present invention, the reverse flow in the pipe can be performed by simply opening the drain valve once without repeating the operation of opening and closing the drain valve by the manual operation or the automatic operation. By using the pulsation generated from the liquid in the tank to enter, it is possible to repeat the diffusing pipe water cleaning of the air diffusing device, which eliminates the need for a washing water tank and a washing pump as conventional equipment, and maintenance workers Can reduce the burden of.

[Brief description of drawings]

FIG. 1 is a front view showing an air diffuser according to an embodiment of the present invention.

FIG. 2 is a perspective view of the air diffuser.

FIG. 3 is a sectional view of a main part of the air diffuser.

FIG. 4 is a sectional view showing a trunk pipe of an air diffuser according to another embodiment of the present invention.

FIG. 5 is a perspective view showing the air diffuser.

FIG. 6 is a bottom view showing the air diffuser.

FIG. 7 is a bottom view showing an air diffuser according to another embodiment of the present invention.

FIG. 8 is a bottom view showing an air diffuser according to another embodiment of the present invention.

FIG. 9 is a bottom view showing an air diffuser according to another embodiment of the present invention.

[Explanation of symbols]

1 aeration tank 2 Air diffuser 3 Membrane separation device 4 Air diffusion case 5 Air diffuser 6 trunk piping 7 branch piping 8 blowers 9 Aeration drain pipe 10 Air jet 11 exhaust port 12 drain valve 13 Guide

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kiyoji Izumi 1-247 Shikitsu Higashi, Naniwa-ku, Osaka-shi, Kubota Co., Ltd. (56) References JP-A-56-13087 (JP, A) Development 64-36099 (JP, U) Actual development 58-141796 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/20

Claims (3)

(57) [Claims] 1. A state of supplying air to a pipe in a diffusing device for supplying air from a base end side to a pipe immersed in a tank and diffusing the air from a plurality of air ejection ports provided below the pipe. Open the drain valve of the diffuser drain pipe connected to the tip side of the pipe with, exhaust the air to be supplied to the pipe through the diffuser drain pipe, and reversely inject the liquid in the tank into the pipe from the air ejection port to connect the pipe. A method for cleaning an air diffuser, which comprises performing water cleaning and intermittently repeating water cleaning using pulsation generated due to a pressure change in a pipe. 2. A trunk pipe, which is soaked in a tank and arranged in a horizontal direction, the base end side of which communicates with an air supply source and a plurality of air ejection ports provided at the bottom, and one end of which communicates with the tip end side of the trunk pipe. as well as a diffuser drain pipe which other end is opened as an exhaust port at a position above the stem pipe, it possesses a drain valve provided in the diffuser drain pipe, gas dispersion in a state for supplying air to the trunk pipe Dore
Open the drain valve of the main pipe, and supply air to the main pipe.
Exhaust through the diffuser drain pipe, and from the air outlet into the main pipe
Backwash the liquid in the tank into the main pipe to wash the main pipe with water.
Rinsing with water intermittently using pulsation caused by pressure change
An air diffuser characterized by repeating cleaning. 3. A trunk pipe, which is soaked in a tank and arranged horizontally so that a base end side communicates with an air supply source, and one end communicates with the trunk pipe, and the other end is an air jet at a position below the trunk pipe. A plurality of branch pipes that open as outlets, one end that communicates with the tip side of the main pipe, and the other end that opens as an exhaust port at a position above the main pipe, and a drain provided in the diffuser drain pipe. have a valve and, in the state for supplying air to the stem pipe
Open the drain valve of the diffuser drain pipe and supply it to the main pipe.
Air is exhausted through the diffused drain pipe, and from the air outlet
Reversely inflow the tank liquid into the branch pipe to
Rinse with water to remove pulsation caused by pressure changes in the main piping
An air diffuser characterized by intermittently repeating washing with water .