Air-dissolved water control system of air floatation tank

Abstract

The utility model belongs to the technical field of dissolved air water control, and particularly relates to a dissolved air water control system of an air floatation tank. The utility model provides a dissolved air water control system of an air floatation tank, which has a good water purification effect. The device comprises an air floatation tank, an outlet of the air floatation tank is respectively connected with an inlet of a clean water tank and an inlet of an air dissolving water pump, an outlet of the air dissolving water pump is connected with an inlet of an air dissolving water tank, an outlet of the air dissolving water tank is connected with an aeration pipe of the air floatation tank, a water inlet of the air floatation tank is connected with an outlet of a PAC dosing device, and an inlet of the air dissolving water tank is connected with an air compressor.

Description

Technical Field

[0001] The utility model belongs to the technical field of dissolved air water control, and particularly relates to a dissolved air water control system for an air flotation tank. Background Art

[0002] The industrial wastewater in the factory is homogenized in a regulating tank, pumped to an inclined tube sedimentation tank by a lift pump to separate large particle suspensions. The separated purified water enters an intermediate water tank, is lifted by an intermediate water pump, and enters a coagulation tank for further treatment. The wastewater treatment system starts the PAC dosing device in interlock according to the operation condition of the intermediate water pump, and adds polyaluminum chloride to the mixer at the outlet pipeline of the intermediate water pump. The water after dosing undergoes a coagulation reaction and mud-water separation in the coagulation tank. The separated flocs and large particle suspensions are discharged from the bottom sewage pipeline of the coagulation tank to a sludge tank for sludge thickening and mud-water separation. The supernatant liquid separated in the coagulation tank enters the rear-end clear water tank through overflow. A clear water pump is arranged in the clear water tank to pump the purified water in the clear water tank to an automatic backwashing filter, and the water discharged from the automatic backwashing filter enters the rear-end water use system.

[0003] By regularly monitoring the quality of process water (reclaimed wastewater), it is found that the quality of the process water is poor and cannot meet the relevant requirements of "GB / T 19923-2005 Urban Sewage Reclamation and Reuse - Quality of Industrial Water for Reuse". By comprehensively checking the industrial wastewater treatment system, it is found that the coagulation tank cannot achieve the designed coagulation effect. Due to the small design size of the coagulation tank and the short water flow passage, the flocs formed after adding polyaluminum chloride cannot fully settle, resulting in poor separation effect. A large amount of flocs and suspensions flow into the clear water tank by self-flow along with the water produced at the top of the coagulation tank. And the automatic backwashing filter has limited capacity for treating high-solid-content wastewater, resulting in the deterioration of the quality of the produced water. Content of the Utility Model

[0004] The utility model aims at the above problems and provides a dissolved air water control system for an air flotation tank with good water purification effect.

[0005] To achieve the above object, the utility model adopts the following technical scheme. The utility model includes an air flotation tank. The outlet of the air flotation tank is respectively connected with the inlet of the clear water tank and the inlet of a dissolved air water pump. The outlet of the dissolved air water pump is connected with the inlet of a dissolved air water tank. The outlet of the dissolved air water tank is connected with the air supply pipe of the air flotation tank. The inlet of the air flotation tank is connected with the outlet of a PAC dosing device. The inlet of the dissolved air water tank is connected with an air compressor.

[0006] As a preferred scheme, a butterfly valve for the inlet of the dissolved air water pump is arranged at the inlet of the dissolved air water pump. The outlet of the dissolved air water pump is sequentially connected with the inlet of the dissolved air water tank through a check valve for the outlet of the dissolved air water pump and a butterfly valve for the outlet of the dissolved air water pump. The outlet of the dissolved air water tank is connected with the air supply pipe of the air flotation tank through a gate valve for the outlet of the dissolved air water tank.

[0007] As another preferred solution, the outlet of the air compressor of the present utility model is connected to the inlet of the dissolved air water tank through a safety valve and a check valve.

[0008] As another preferred solution, the water inlet of the PAC dosing device of the present utility model is successively connected to the pipeline of the whole plant's industrial wastewater through an intermediate water tank, an inclined tube sedimentation tank, and an industrial wastewater regulation tank. The inlets of the first backwash filter and the second backwash filter are connected to the outlet of the water pump arranged in the clear water tank, and the outlets of the first backwash filter and the second backwash filter are connected to the pipeline for the reuse of process water at the back end; the blowdown ports of the first backwash filter and the second backwash filter are connected to the sewage inlet of the sludge treatment system.

[0009] As another preferred solution, the outlet of the air flotation tank of the present utility model is successively connected to the inlet of the clear water tank and the inlet of the butterfly valve of the dissolved air water pump through a sleeve regulating valve and a tee.

[0010] As another preferred solution, the blowdown port of the air flotation tank of the present utility model is connected to the sewage inlet of the sludge treatment system.

[0011] As another preferred solution, liquid level sampling ports are arranged at the upper and lower parts of the dissolved air water tank of the present utility model. The liquid level sampling ports are connected to a remote differential pressure liquid level transmitter, the detection signal output port of the remote differential pressure liquid level transmitter is connected to the detection signal input port of the PLC, and the frequency conversion control signal output port of the PLC is connected to the frequency conversion control signal input port of the dissolved air water pump.

[0012] As another preferred solution, the outlet of the air flotation tank of the present utility model is arranged in the middle of the air flotation tank in the height direction.

[0013] Secondly, the aeration pipe of the air flotation tank of the present utility model includes seven columns of vertical pipes, and three air outlet holes are arranged on each column of vertical pipes, and an aeration head is installed at the air outlet holes.

[0014] In addition, the start-stop control signal input port of the air compressor of the present utility model is connected to the control signal output port of the internal pressure switch of the dissolved air water tank.

[0015] Advantages of the present utility model.

[0016] The present utility model is provided with a dissolved air water pump, a dissolved air water tank and an air compressor. The dissolved air water pump pumps water from the middle of the air flotation tank, and together with the air compressor, pumps water and air into the dissolved air water tank. A large amount of air is dissolved in the water in the dissolved air water tank to form dissolved air water, which is used as a working medium. Through the aeration pipe of the air flotation tank, the pressure is suddenly reduced and quickly released, generating a large number of fine bubbles that adhere to the "alum flowers" in the wastewater, causing the flocs to float, so as to quickly remove the polluted impurities in the water and achieve the purpose of purifying water.

[0017] The utility model replaces the existing coagulation tank with a dissolved air flotation tank, and makes relevant improvements accordingly, which improves the water quality of the produced water, has a low transformation cost and a small floor area. Description of the Drawings

[0018] The following further describes the utility model in conjunction with the drawings and specific embodiments. The protection scope of the utility model is not limited to the description of the following content.

[0019] Figure 1 It is a schematic structural diagram of the utility model.

[0020] Figure 2 It is a schematic diagram of the internal structure of the dissolved air flotation tank of the utility model. Specific Embodiments

[0021] As shown in the figure, the utility model includes a dissolved air flotation tank. The outlet of the dissolved air flotation tank is respectively connected to the inlet of the clear water tank and the inlet of the dissolved air pump. The outlet of the dissolved air pump is connected to the inlet of the dissolved air water tank. The outlet of the dissolved air water tank is connected to the aeration pipe of the dissolved air flotation tank. The inlet of the dissolved air flotation tank is connected to the outlet of the PAC dosing device.

[0022] A butterfly valve for the inlet of the dissolved air pump is arranged at the inlet of the dissolved air pump. The outlet of the dissolved air pump is sequentially connected to the inlet of the dissolved air water tank through a check valve for the outlet of the dissolved air pump and a butterfly valve for the outlet of the dissolved air pump. The outlet of the dissolved air water tank is connected to the aeration pipe of the dissolved air flotation tank through a gate valve for the outlet of the dissolved air water tank.

[0023] The inlet of the dissolved air water tank is connected to an air compressor.

[0024] The outlet of the air compressor is connected to the inlet of the dissolved air water tank through a safety valve and a check valve.

[0025] The inlet of the PAC dosing device is sequentially connected to the whole plant industrial wastewater incoming pipe through an intermediate water tank, an inclined tube sedimentation tank and an industrial wastewater regulation tank. The inlets of the first backwash filter and the second backwash filter are connected to the outlet of a clear water pump arranged in the clear water tank. The outlets of the first backwash filter and the second backwash filter are connected to the subsequent process water reuse pipe. The blowdown ports of the first backwash filter and the second backwash filter are connected to the sludge inlet of the sludge treatment system. The backwash filter regularly discharges sludge to the sludge thickening tank of the sludge treatment system. The PAC dosing device is a conventional existing structure, including a dosing storage tank, a dosing pump, pipeline valves and a pipeline mixer. The dosing pump pumps the medicine into the pipeline mixer at the inlet pipeline of the dissolved air flotation tank (the inlet of the pipeline mixer is the inlet of the PAC dosing device), and is preliminarily mixed with the raw water in the pipeline mixer. The mixed water enters the dissolved air flotation tank.

[0026] Pumps are arranged between the industrial wastewater regulation tank and the inclined tube sedimentation tank and at the outlet of the intermediate water tank.

[0027] The flotation tank is an above-ground structure, while the clear water tank, intermediate water tank and regulating tank are all underground tanks. The water produced by the flotation tank flows into the clear water tank by gravity.

[0028] The outlet of the air flotation tank is connected to the inlet of the clean water tank and the inlet of the butterfly valve of the dissolved air water pump respectively through the sleeve regulating valve and the three-way connection.

[0029] The outlet of the flotation tank is arranged in the middle of the height direction of the flotation tank. The water outlet of the flotation tank is arranged at the middle height of the tank, which prevents the large suspended particles accidentally leaked from the front section of the flotation tank or the floccules that are not supported by the dissolved air water in time after the coagulation reaction from entering the water production pipeline, causing the water quality of the produced water to deteriorate. At the same time, taking water from the middle can ensure the water quality entering the dissolved air water pump, reduce the wear of the shaft seal water wheel during the operation of the dissolved air water pump, and prevent the above-mentioned large suspended particles or floccules from blocking the outlet check valve of the dissolved air water pump, causing the dissolved air water pump to run without pumping water during operation, and even cause the machine seal to burn out. The releaser designed by the utility model (that is, the aeration pipe of the flotation tank includes seven rows of vertical pipes, each row of vertical pipes is arranged with three air outlets, and an aeration head is installed at the air outlet) can ensure that the dissolved air effect is efficient and stable, and there is no need to adopt the traditional flotation system to take the produced water from the bottom of the flotation tank. There is no defect that the dissolved air water support effect of the original flotation system is poor and the product water must be taken from the bottom.

[0030] The sewage outlet of the air flotation tank is connected to the sewage inlet of the sludge treatment system.

[0031] The upper and lower parts of the dissolved air water tank are provided with liquid level sampling ports, which are connected to the remote differential pressure liquid level transmitter, the detection signal output port of the remote differential pressure liquid level transmitter is connected to the detection signal input port of the PLC, and the frequency conversion control signal output port of the PLC is connected to the frequency conversion control signal input port of the dissolved air water pump. The sampling pipeline is connected from the gas side at the top of the dissolved air water tank to the water side at the bottom, and connected to the remote differential pressure liquid level transmitter. The remote differential pressure liquid level transmitter transmits the internal liquid level analog quantity of the dissolved air water tank to the PLC, and the PLC compares and judges the received analog quantity with the set quantity, and controls the frequency of the dissolved air water pump through PID regulation.

[0032] During operation, you only need to open the gate valve at the outlet of the dissolved air tank to the specified opening to ensure that the dissolved air effect in the flotation tank is good enough. At this time, the dissolved air tank liquid level is automatically activated, and the PLC automatically tracks the dissolved air tank liquid level and adjusts the operating frequency of the dissolved air pump to avoid serious losses and poor dissolved air effect caused by frequent start and stop of the dissolved air pump, which not only ensures the water quality of the produced water, but also saves operating consumables. At the same time, the PLC is used to perform PID tracking and adjustment based on the feedback value of the remote differential pressure level transmitter, avoiding human intervention, improving the precision of control, and improving the intelligent automation of the wastewater treatment system.

[0033] The aeration pipe of the dissolved air flotation tank includes seven columns of vertical pipes, with three air outlets arranged on each column of vertical pipes, and aeration heads are installed at the air outlets. The utility model controls the operation of the dissolved air water tank through PLC, can precisely control the dissolved air water tank, and cooperates with a total of 21 air outlets in seven columns, with uniform air output, ensuring that a sufficient amount of micro bubbles are formed in the dissolved air flotation tank, making the aeration effect in the dissolved air flotation tank uniform and improving the dissolved air flotation effect.

[0034] The start-stop control signal input port of the air compressor is connected to the control signal output port of the internal pressure switch of the dissolved air water tank. It can be set to start the air compressor when the internal pressure of the dissolved air water tank is lower than 0.4 MPa. The air compressor provides air pressure inside the dissolved air water tank.

[0035] The sludge treatment system is an existing conventional technology, consisting of a sludge thickening tank, a sludge screw machine, pipelines, valves, and a centrifuge. An sludge remover is arranged inside the sludge thickening tank, and the thickened sludge inside the sludge thickening tank is pumped to the centrifuge by the sludge screw machine. The centrifuge rotates at a high speed to separate the mud and water, and the separated clear water is pumped back to the sludge thickening tank. The thickened and dewatered sludge is sent to the coal yard for drying (i.e., Figure 1 "sludge transported out for disposal" in

[0036] By adjusting the sleeve regulating valve, the liquid level of the dissolved air flotation tank is controlled to operate 2 cm to 3 cm above the lower edge of the scraper of the sludge scraper. The sludge scraper is controlled by PLC, and reciprocates and operates the sludge scraping operation 3 times every 4 hours, scraping the sludge to the sludge pipeline and bringing it to the sludge thickening tank of the sludge treatment system along with the water flow. The setting of the sludge scraper and the sludge pipeline at the upper end of the dissolved air flotation tank is an existing conventional structure. Contact switches can also be set in the middle of the scraping track of the existing sludge scraper, at both ends of the forward and reverse travel, to monitor the operating position of the sludge scraper. When the guide wheel of the sludge scraper touches the photosensitive switch, the corresponding position contact switch transmits the on-off digital quantity to the digital quantity input port of the PLC. When the PLC receives the switch quantity triggers of the reverse end - middle - forward end in sequence, it is recorded as the end of one forward travel. After a 10-second delay, the motor of the sludge scraper is controlled to reverse. When the PLC receives the switch quantity triggers of the forward end - middle - reverse end in sequence, it is recorded as the end of one reverse travel. Repeating the above operation three times is one sludge scraping cycle. The PLC times 4 hours through a timer, and repeats the above operation when the time is up. This sludge scraper control system realizes the automatic control of forward and reverse travel, avoiding the situation where the forward and reverse travel of the traditional sludge scraper needs to be manually controlled on-site, and avoiding the occurrence of derailment of the guide wheel of the sludge scraper when the motor of the sludge scraper is blocked or the limit is abnormal. Adjusting the liquid level of the connected container through the sleeve regulating valve is an existing conventional technology.

[0037] During operation, after the dissolved air water tank reaches the set pressure and water level, adjust the opening degree of the gate valve at the outlet of the dissolved air water tank so that dense bubbles appear at the top of the air flotation tank. At this time, the gate valve at the outlet of the dissolved air water tank does not need to be adjusted anymore. It is necessary to avoid a large opening degree of the outlet gate valve, which may lead to insufficient output of the dissolved air water pump, the inlet water cannot meet the requirements of the backend, and the compressed air generated by the air compressor directly enters the air flotation tank through the outlet gate of the dissolved air water tank without being proportionally mixed with water, forming a large amount of "flowering" in the air flotation tank. The sudden release of gas causes the water flow velocity at this part to be too fast, resulting in the flocs generated by the coagulation reaction being redispersed, affecting the treatment effect of the system. At the same time, if the gate valve at the outlet of the dissolved air water tank is too small, it will lead to too low a dissolved air water volume entering the air flotation tank, and insufficient tiny bubbles can be formed to lift the flocs generated by the coagulation reaction and remove them from the inside of the air flotation tank through the sludge scraper. The liquid level of the dissolved air water tank is automatically controlled, and the PLC will perform PID tracking adjustment according to the detection value of the remote differential pressure type liquid level transmitter.

[0038] It can be understood that the above specific description of the present invention is only for explaining the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as it meets the usage requirements, it is within the protection scope of the present invention.

Claims

1. A flotation tank dissolved air and water control system, characterized in that: The invention comprises an air flotation tank, the outlet of which is respectively connected to the inlet of the clean water tank and the inlet of the dissolved air water pump, the outlet of the dissolved air water pump is connected to the inlet of the dissolved air water tank, the outlet of the dissolved air water tank is connected to the aeration pipe of the air flotation tank, the water inlet of the air flotation tank is connected to the outlet of the PAC dosing device, and the inlet of the dissolved air water tank is connected to the air compressor.

2. A flotation tank dissolved air and water control system according to claim 1, characterized in that The inlet of the dissolved air water pump is provided with an inlet butterfly valve of the dissolved air water pump, and the outlet of the dissolved air water pump is connected to the inlet of the dissolved air water tank through the outlet check valve of the dissolved air water pump and the outlet butterfly valve of the dissolved air water pump in sequence; the outlet of the dissolved air water tank is connected to the aeration pipe of the flotation tank through the outlet gate valve of the dissolved air water tank.

3. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The outlet of the air compressor is connected to the inlet of the dissolved air water tank through a safety valve and a check valve.

4. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The water inlet of the PAC dosing device is connected to the industrial wastewater pipeline of the whole plant through the intermediate water tank, the inclined tube sedimentation tank, and the industrial wastewater regulating tank in sequence; the inlet of the first backwash filter and the inlet of the second backwash filter are connected to the outlet of the clean water pump arranged in the clean water tank; the outlet of the first backwash filter and the outlet of the second backwash filter are connected to the process water recycling pipeline to the rear end; the sewage outlet of the first backwash filter and the sewage outlet of the second backwash filter are connected to the sewage inlet of the sludge treatment system.

5. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The outlet of the air flotation tank is connected to the inlet of the clean water tank and the inlet of the butterfly valve of the dissolved air water pump respectively through the sleeve regulating valve and the three-way connection.

6. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The sewage outlet of the air flotation tank is connected to the sewage inlet of the sludge treatment system.

7. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The upper and lower parts of the dissolved air water tank are provided with liquid level sampling ports, which are connected to a remote differential pressure liquid level transmitter, a detection signal output port of the remote differential pressure liquid level transmitter is connected to a detection signal input port of a PLC, and a frequency conversion control signal output port of the PLC is connected to a frequency conversion control signal input port of a dissolved air water pump.

8. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The air flotation tank outlet is arranged in the middle of the air flotation tank in the height direction.

9. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The aeration pipe of the air flotation tank comprises seven rows of vertical pipes, three air outlets are arranged on each row of vertical pipes, and aeration heads are installed at the air outlets.

10. The air flotation tank dissolved air and water control system according to claim 1, characterized in that The start / stop control signal input port of the air compressor is connected to the control signal output port of the pressure switch inside the dissolved air water tank.

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