JP4481887B2 - Aeration system - Google Patents

Description

  The present invention relates to an air diffusion system having a function of preventing clogging of an air diffuser that supplies bubbles for aeration into water to be treated.

  In general, in fields such as clean water treatment, sewage treatment, and human waste treatment, a diffused gas is installed in a reaction tank, air is blown into the diffused gas with a constant air volume control, and bubbles are generated from the diffused gas into the liquid to be treated. There is an aeration process for supplying and aeration. Until now, diffuser plates, diffused cylinders, etc. have been used as diffused gas, but in recent years, membrane-based ones have come to be used. The air diffused by the membrane has a flexible film body such as rubber or synthetic resin, and has a number of fine air diffused holes provided on the surface thereof. In this diffused gas, the inside of the membrane (film body) is expanded by blowing air inside to open the diffuser holes, and fine bubbles are released from the diffuser holes.

  The diffused gas using such a membrane can reduce the size of the diffused bubbles as compared with the diffuser plate and the diffused cylinder, so that the amount of gas-liquid contact is increased when compared with the same amount of air. . For this reason, the amount of diffused air is small, and the amount of air blown from the diffused blower can be reduced. However, since the air diffusion holes are small, blockage of sludge and the like has been a problem.

Then, the proposal about the operation method which prevents clogging of the diffuser using a membrane is made (for example, refer patent document 1). In this operation method, sludge and the like blocked by the air diffusion holes are removed by repeating expansion / reduction of the membrane several times. Here, the membrane is expanded by the air sent into the diffused gas in the normal diffused state. In order to reduce the membrane, an air valve (which may use an air volume adjusting valve) is closed, and a pressure release valve (pressure relief valve) existing between the air valve and the diffused gas is opened. By repeating the expansion / reduction of the membrane several times by the air supply operation with respect to the air diffusion, and the air supply interruption and pressure release operation, sludge and the like blocked in the air diffusion holes are removed.
JP 2004-313938 A

  Conventionally, the operation for removing clogging of the diffused gas using such a membrane has been periodically performed at predetermined time intervals. However, the time until the diffused gas clogs varies depending on the quality of the water to be treated. For this reason, as described above, when the clogging prevention operation interval is set to a fixed time interval set by a timer or the like, if the water quality is poor, the water is blocked earlier than the set time, and the target air volume cannot be maintained. Will occur. On the other hand, if the water quality is good, the clogging removal operation will be carried out after the set time has passed even though there is no actual clogging, resulting in a decrease in the air diffusion efficiency due to the excessive clogging removal operation, etc. The problem occurred.

  An object of the present invention is to appropriately detect clogging by grasping the clogged state of the diffused gas, to prevent excessive clogging removal operation, and to maintain an appropriate amount of diffused air. Qi is to provide a system.

  The air diffusion system of the present invention is provided with a large number of air holes on the surface, and measures the amount of air diffused from the air holes to discharge bubbles into the liquid to be treated and the amount of air supplied to the air supply path to the air diffused. And an air volume adjustment function that is provided in the air supply path and is controlled in opening so that the air volume measured by the air volume meter maintains the set air volume, and is supplied A valve device having a function to shut off air and a pressure release function to release supply air to the diffused gas in a supply air shut-off state, and an opening degree by the air volume adjustment function of the valve device is greater than a set value and measured Clogging detection means for determining that the diffused gas is clogged when a state in which the deviation between the actual airflow and the set airflow is large continues for a set time or longer, and executing a predetermined clogging removal operation. It is characterized by that.

  The air diffusion system of the present invention is provided with a large number of air diffusion holes on the surface portion, a diffused gas for releasing air bubbles into the liquid to be treated from the air diffusion holes, and a supply airflow flowing through the air supply path to the diffused gas An air volume meter for measuring the air volume, and an air volume adjustment function that is provided in the air supply path and whose opening degree is controlled so that the air volume measured by the air volume meter maintains the set air volume, and A valve device having a function of shutting off the supply air and a pressure release function of releasing the supply air to the diffused gas in the supply air shut-off state, a diffuser pressure gauge for measuring the pressure in the air supply path, and the diffuser The liquid level meter that measures the liquid level in the reaction tank in which the gas is provided, and the measured values of the diffuser pressure gauge and the liquid level meter in the air supply state to the diffused gas by the valve device are input, and these measurements are made. Based on diffuse pressure loss and air volume If the state where the difference from the normal pressure loss is equal to or greater than a set value continues for a set time or longer, it may be determined that the diffused gas is clogged, and a clogging detection unit that performs a predetermined clogging removal operation may be provided. .

  The air diffusion system of the present invention is provided with a large number of air diffusion holes on the surface portion, a diffused gas for releasing air bubbles into the liquid to be treated from the air diffusion holes, and a supply airflow flowing through the air supply path to the diffused gas An air volume meter for measuring the air volume, and an air volume adjustment function that is provided in the air supply path and whose opening degree is controlled so that the air volume measured by the air volume meter maintains the set air volume, and A valve device having a function of blocking supply air, and a pressure release function of releasing supply air to the diffused gas in the supply air blocked state, and a shape and distribution of bubbles released from the diffused gas into the liquid to be treated If the bubble state detection means for detecting the state and the state of the bubble detected or detected by the bubble state detection means are different from the set shape and distribution state for a set time or more, clogging of the diffused gas Judgment, place A clogging detecting means for executing an operation of clogging removal may be configured with a.

  In the present invention, the clogging removing operation is an operation of alternately repeating the operation of shutting off and releasing the air blown to the diffused gas and the air blowing operation to the diffused gas by the valve device.

  In the present invention, the bubble state detection means irradiates the bubbles released into the liquid to be treated with ultrasonic waves or radio waves, and detects the bubble state by the reflected waves.

  According to the present invention, in the air supply path, the relationship between the air flow adjustment valve opening and the measured air flow value, the relationship between the aeration pressure and the liquid level in the reaction tank, or the bubbles released from the air diffusion The clogging state of the diffused gas is detected from the shape / distribution state and the clogging removal operation is performed, so appropriate clogging prevention operation can be performed, and excessive clogging removal operation can be prevented to ensure proper air diffusion. The air volume can be maintained.

  Hereinafter, an embodiment of an air diffusion system according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a main configuration of the present embodiment. In FIG. 1, a reaction tank 11 is connected to pipes 12 and 13, and a liquid to be treated such as sewage flowing in through the pipe 12 is aerated and flows out from the pipe 13. Reference numeral 14 denotes a diffused gas, which uses, for example, a membrane or the like. A large number of diffused holes are provided on the surface portion, and bubbles are released into the liquid to be treated from the diffused holes.

  An air supply path 15 is connected to the diffused gas 14, and air is supplied from an air source such as a blower (not shown). The air supply passage 15 is provided with an air diffuser 16 for measuring the amount of supplied air flowing therethrough and a valve device 17 composed of a plurality of valves described later. The valve device 17 includes an air volume control valve 171, an air shut-off valve 172, and a pressure release valve 173. The air volume adjusting valve 171 is provided in the air supply path 15 and is controlled in opening degree so that the air volume measured by the air volume meter 16 maintains the set air volume, and has an air volume adjusting function. The air shut-off valve 172 has a function of shutting off supply air to the diffused gas 14. The pressure release valve 173 opens in the air shut-off state by the air shut-off valve 172 and has a pressure release function for releasing the supply air to the diffused gas 14.

  A supply air amount (aeration air amount) value to the air diffuser 14 is set for the air amount adjusting valve 171. The set air volume 18 may be a preset fixed value, a value proportional to a measured value of the flow meter 20 provided in the inflow pipe 12 (inflow amount into the reaction tank 11), Any one of the values for controlling the dissolved oxygen measurement value by a provided DO meter (not shown) may be used. This air volume setting value 18 is given as SV to the controller 21, compared with the PV value (process value: actual air volume) measured by the diffuser air volume meter 16, and MV (operation value: air volume adjustment) by a predetermined calculation. The opening operation value of the valve 171) is calculated. This MV value is output to the drive motor 171M of the air volume adjusting valve 171.

  Reference numeral 22 denotes a clogging detection means, to which a measurement value (valve opening degree) by an opening meter 23 provided in the air volume control valve 171 and an actual air volume measured by the aeration air volume meter 16 are input. Then, when the valve opening is equal to or greater than a preset value and the state where the deviation between the measured actual air volume and the set air volume 18 is large continues for a set time or longer, it is determined that the diffused gas 14 is clogged. That is, the actual air volume (aeration air volume) does not reach the set air volume 18 even though the air volume adjusting valve 171 is opened more than a certain opening (set opening), and the deviation from the set air volume 18 is large. In this case, it is determined that the diffused gas 14 is clogged.

  When the clogging detection means 22 detects the occurrence of clogging, it performs a predetermined clogging removal operation. The predetermined clogging removal operation is, for example, an operation of alternately repeating the operation of shutting off and releasing the blown air to the diffused gas 14 by the valve device 17 and the blowing operation to the diffused gas 14. For this reason, the clogging detection means 22 outputs operation commands for clogging removal to the drive motor 172M of the air shut-off valve 172 and the drive motor 173M of the pressure release valve 173, respectively.

  Next, the operation will be described. To-be-treated water such as sewage flows into the reaction tank 11 through the pipe 12. Air is supplied from an air source (not shown) through an air supply path 15 to the diffused gas 14 provided at the bottom of the reaction tank 11 and is diffused into the liquid to be treated as bubbles. At this time, the air cutoff valve 172 is in an open state, and the pressure release valve 173 is in a closed state. Further, the air volume control valve 171 is controlled in opening degree by the controller 21 so as to satisfy the set air volume 18.

  Here, the amount of diffused air varies depending on the state of the liquid to be treated and the degree of contamination of the diffused gas 14. For this reason, the air volume constant control is performed by changing the opening degree of the air volume control valve 16 by the controller 21 using the actual air volume measured by the air volume meter 16.

  In such a diffuser system, when the diffused gas 14 starts to be blocked due to long-term use or the like, the pressure loss of the diffused gas 14 increases and the actual air volume decreases, so that the opening of the air volume adjusting valve 171 increases to compensate for this. Become. Further, when the diffused gas 14 becomes clogged and deviates from the air volume adjustment range, control cannot be performed while the opening degree of the air volume adjustment valve 171 is maximized. The clogging detection means 22 detects this state and commands a clogging removal operation.

  That is, the clogging detection means 22 receives the opening information of the air volume adjusting valve 171 from the opening meter 23, and the opening of the air volume adjusting valve 171 is larger than the set opening as shown in FIG. 201) and when the deviation between the set air flow and the actual air flow is large (step 202) and the state continues for a certain time or longer (step 203), it is determined that the diffused air 14 is clogged and is in a closed state. The clogging removal operation is started (step 204).

  The clogging removal operation is, for example, closing the air shut-off valve 172 and opening the pressure release valve 173 to interrupt the air diffused from the diffused gas 14, and then opening the air shut-off valve 172 and releasing the pressure release valve. 173 is closed to diffuse air from the diffused gas 14. By repeating this discontinuation of air diffusion and resumption of air diffusion several times, dirt such as sludge adhering to the air diffuser holes of the air diffuser 14 is eliminated. In particular, when the surface of the diffused gas 14 is a membrane, the membrane expands by blowing air to the diffused gas and expands the diffused holes to release bubbles, and when the blowing is stopped, the membrane shrinks and the diffused holes also shrink. Therefore, by repeating this blowing and blowing stop and repeating the expansion and contraction of the membrane and its diffuser holes, the dirt attached to the diffuser hole portions can be effectively removed.

  In this manner, the blockage of the diffused gas 14 can be determined from the relationship between the valve opening degree of the air volume adjusting valve 171 and the actual air volume, and the blockage removal process can be started based on the determination. Compared to cleaning, appropriate blockage removal can be performed, and stable continuous operation of the diffused gas can be performed.

  Next, the embodiment shown in FIG. 3 will be described. In this embodiment, the clogged state of the diffused gas 14 is detected by a change in the diffused air pressure loss. In FIG. 3, this aeration system is also a system in which a liquid to be treated such as sewage flowing into the reaction tank 11 from the pipe 12 is aerated by the aeration from the diffused gas 14 and flows out from the pipe 13. An air supply path 15 is connected to the diffused gas 14, and the air supply path 15 is provided with a diffusing air flow meter 16, and a valve device 17 including an air volume adjusting valve 171, an air shut-off valve 172, and a pressure release valve 173. ing. The air volume control valve 171 is controlled by the controller 21 so that the air volume set value 18 is maintained.

  The configuration so far is the same as that of the embodiment of FIG. 1, but the method for detecting clogging of the diffused gas 14 is different. That is, an aeration pressure gauge 31 is provided in the air supply pipe 15, and a liquid level gauge 32 is provided in the reaction tank 11 in order to measure the liquid level. The clogging detection means 33 inputs the measured values of the aeration pressure gauge 31 and the liquid level gauge 32 and the actual air volume from the air volume meter 16.

  The clogging detection means 33 detects clogging of the diffused gas 14 as follows based on each input measurement information. That is, the diffused air pressure loss and the blocking pressure loss are obtained from the measured values of the diffuser pressure gauge 31 and the liquid level gauge 32 by the following equations (1) and (2).

Diffuse pressure loss = Diffuse pressure-Liquid level x Specific gravity (1)
Blocking pressure loss = diffuse air pressure loss-normal pressure loss due to air volume (2)
In other words, if the state where the blockage pressure loss, which is the difference between the diffused air pressure loss and the normal pressure loss based on the air volume, is equal to or greater than the set value continues for a set time or longer, it is determined that the diffused gas 14 is clogged, and the predetermined clogging removal operation Is executed.

  In the above configuration, when the diffused gas 14 is clogged, the diffused pressure increases. Since the diffused air pressure varies depending on the amount of diffused air and the water level in the reaction tank 11, the clogging detecting means 33 calculates only the blockage pressure loss increased by the blockage using the above formulas (1) and (2). Then, as shown in FIG. 4, it is determined whether or not the occlusion pressure loss value obtained by this calculation deviates greatly from the expected value (a state equal to or greater than the set value) (step 401). When the state equal to or higher than this set value continues for a certain time or longer (step 402), it is determined that the diffused gas 14 is clogged and is in a closed state, and the clogging removal operation is started (step 403).

  In this way, the blockage of the diffused gas 14 can be determined from the change in the diffused air pressure loss obtained from the measured value of the diffused pressure gauge 31, and the blockage removal operation can be started based on the determination, so that the conventional constant interval is used. Compared to those that perform cleaning, it is possible to carry out appropriate blockage removal, and stable continuous operation of the diffused gas can be performed.

  Next, the embodiment shown in FIG. 5 will be described. In this embodiment, the clogged state of the diffused gas 14 is detected from the shape of bubbles generated from the diffused gas 14 or the distribution state thereof. That is, there is a difference in the shape (size) and distribution of bubbles generated from the diffused gas 14 before and after clogging of the diffused gas 14.

  For example, in the case of the diffused gas 14 using a membrane, if clogging occurs, the bubble diameter becomes larger than before clogging. This is because the internal pressure of the diffused gas 14 increases due to clogging, so that the membrane expands greatly, and when the bubbles are released, the diffused holes are also greatly expanded. Further, when clogging occurs, the distribution of bubbles released from the diffused gas 14 is biased. That is, a large number of diffused holes are hardly clogged uniformly, and the degree of clogging differs for each portion, so that the distribution of released bubbles also differs.

  Therefore, the clogging of the diffused gas 14 can be detected by identifying the shape of the bubbles generated from the diffused gas 14 or the distribution state thereof.

  In this embodiment, bubble state detection means 51 for detecting the shape and distribution state of bubbles released from the diffused gas 14 into the liquid to be treated is provided in the reaction tank 11. The clogging state detection unit 52 determines whether the shape or distribution state of the bubbles detected by the bubble state detection unit 51 is different from the set shape and distribution state by image processing or the like. When the different state continues for a set time or longer, it is determined that the diffused gas 14 is clogged and a predetermined clogging removal operation is executed.

  As the bubble state detection means 51, for example, a device that irradiates the bubbles released into the liquid to be treated with ultrasonic waves or radio waves and detects the bubble state by the reflected waves may be used. Of course, the present invention is not limited to such an apparatus, and any apparatus capable of detecting the shape and distribution of bubbles may be used.

  As described above, by detecting the shape and distribution state of the bubbles released from the diffused gas 14, the blockage of the diffused gas 14 can be determined, and the blockage removing process can be started based on the determination. Compared to cleaning at regular intervals, appropriate blockage removal can be performed, and stable continuous operation of the diffused gas can be performed.

It is a block diagram which shows one Embodiment of the aeration system by this invention. It is a flowchart explaining operation | movement of one Embodiment same as the above. It is a block diagram which shows other embodiment of this invention. It is a flowchart explaining the operation | movement of other embodiment same as the above. It is a block diagram which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Reaction tank 14 Air diffuser 15 Air supply path 16 Air flow meter 17 Valve apparatus 171 Air volume control valve 172 Air shut-off valve 173 Relief valve 22, 33, 52 Clogging detection means 51 Bubble state detection means

Claims (5)

A large number of air holes are provided on the surface, and the air diffused to release bubbles from the air holes into the liquid to be treated;
An air diffuser for measuring the amount of air supplied to the air supply path to the air diffuser;
A function that is provided in the air supply path and has an air volume adjustment function in which the opening degree is controlled so that the air volume measured by the air volume meter maintains the set air volume, and the function of shutting off the supplied air; and A valve device having a pressure release function for releasing supply air to the diffused gas in a supply air shut-off state;
If the opening degree by the air volume adjustment function of the valve device is greater than or equal to a set value and the state where the deviation between the measured actual air volume and the set air volume is large continues for a set time or more, it is determined that the diffused gas is clogged. A clogging detecting means for executing a predetermined clogging removing operation;
A diffuser system characterized by comprising: A large number of air holes are provided on the surface, and the air diffused to release bubbles from the air holes into the liquid to be treated;
An air diffuser for measuring the amount of air supplied to the air supply path to the air diffuser;
A function that is provided in the air supply path and has an air volume adjustment function in which the opening degree is controlled so that the air volume measured by the air volume meter maintains the set air volume, and the function of shutting off the supplied air; and A valve device having a pressure release function for releasing supply air to the diffused gas in a supply air shut-off state;
An aeration pressure gauge for measuring the pressure in the air supply path and a liquid level gauge for measuring the liquid level of a reaction tank in which the diffusion gas is provided;
Input the measured values of the diffuser pressure gauge and the liquid level gauge in the air supply state to the diffused gas by the valve device, and set the difference between the diffused pressure loss obtained from these measured values and the normal pressure loss based on the air volume A clogging detecting means for determining a clogging of the diffused gas and performing a predetermined clogging removing operation when the state of the value or more continues for a set time or more;
A diffuser system characterized by comprising: A large number of air holes are provided on the surface, and the air diffused to release bubbles from the air holes into the liquid to be treated;
An air diffuser for measuring the amount of air supplied to the air supply path to the air diffuser;
A function that is provided in the air supply path and has an air volume adjustment function in which the opening degree is controlled so that the air volume measured by the air volume meter maintains the set air volume, and the function of shutting off the supplied air; and A valve device having a pressure release function for releasing supply air to the diffused gas in a supply air shut-off state;
A bubble state detecting means for detecting the shape and distribution state of bubbles released from the diffused gas into the liquid to be treated;
When the bubble shape or distribution state detected by the bubble state detection means is different from the set shape and distribution state for a set time or longer, it is determined that the diffused gas is clogged, and a predetermined clogging removal operation is performed. Clogging detecting means for executing
A diffuser system characterized by comprising:   The clogging removal operation is an operation in which the air blow to the diffused gas is interrupted by the valve device, and the operation to release the pressure and the air blow to the diffused gas are alternately repeated. Aeration system as described in Crab.   The aeration system according to claim 3, wherein the bubble state detection means irradiates the bubbles released into the liquid to be treated with ultrasonic waves or radio waves, and detects the bubble state based on the reflected waves.

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