A device for stabilizing dissolved oxygen in sewage treatment system

Abstract

The present invention provides a device for stabilizing dissolved oxygen in a sewage treatment system, belonging to the technical field of dissolved oxygen treatment equipment. The device comprises: a detection module, a control box, a frequency converter and an aerator. When the system operates in an automatic state, a PLC controls the frequency converter to start. The PLC performs PID adjustment based on the error between a set dissolved oxygen value and an actual detected dissolved oxygen value, and outputs a frequency setting signal to the frequency converter. The frequency converter ensures that the dissolved oxygen remains within a small range above and below the set value based on the frequency setting signal and a preset aerator speed, thereby achieving stable operation of a constant dissolved oxygen value. The device can efficiently and conveniently stabilize the dissolved oxygen in water to an appropriate range, and can ensure long-term safe and stable operation.

Description

Technical Field

[0001] The invention belongs to the technical field of dissolved oxygen treatment and relates to a device for stabilizing dissolved oxygen in a sewage treatment system. Background Art

[0002] Dissolved oxygen is closely related to sludge concentration. High activated sludge concentration has a significantly higher demand for dissolved oxygen than low activated sludge concentration. Dissolved oxygen is related to the amount of organic matter in the raw water. Specifically, the more organic matter there is in the raw water, the more dissolved oxygen microorganisms need to consume to metabolize and decompose these organic matter, and vice versa. Dissolved oxygen is also related to some special components in the raw water. For example, the presence of detergents in the water creates an isolation layer on the surface of the aeration tank that isolates the atmosphere, affecting the improvement of aeration effect.

[0003] Among them, the patent with publication number CN210559634U discloses an automatic stabilization control system for dissolved oxygen, including an anoxic tank and an aerobic tank; it also includes a controller, a delay device, a dissolved oxygen probe, an aeration device, and a frequency converter. The document adopts a method of calculating the average value; the average value is compared with the dissolved oxygen target value set by the data setting module. If it does not meet the requirements, the frequency is repeatedly adjusted to adjust it within the range by trial and error. This method has low efficiency in regulating dissolved oxygen, easily causes frequent start and stop of the equipment, and is not conducive to the long-term, effective, safe and stable operation of the equipment. Therefore, how to efficiently and conveniently stabilize the dissolved oxygen in the water to an appropriate range and achieve long-term, safe and stable operation of the equipment is a technical problem that needs to be solved. Summary of the Invention

[0004] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a device for stabilizing dissolved oxygen in a sewage treatment system, comprising: a detection module, a control box, a frequency converter and an aerator, the detection module being connected to a first port of the control box, the second port of the control box being connected to one end of the frequency converter, and the other end of the frequency converter being connected to the aerator; the detection module comprising a detection probe and a meter for detecting the dissolved oxygen concentration; the control box comprising a PLC for receiving dissolved oxygen concentration information, processing the information to obtain dissolved oxygen and frequency converter curves, and adjusting the operation of the frequency converter according to the dissolved oxygen and frequency converter curves; the frequency converter ensures that the dissolved oxygen remains within a small range above and below the set value based on a given frequency signal and a pre-set aerator speed, thereby achieving stable operation of a constant dissolved oxygen value.

[0005] Furthermore, the detection module includes a mounting frame, a probe junction box, a reinforced polyethylene tube, and a cleaning fluid. The mounting frame is fixedly installed at the edge of the pool. The mounting frame installs the probe junction box above the pool. The pool contains sewage. The mounting frame adopts a tubular bracket. A plurality of clamps are provided on the tubular bracket. The clamps are used to clamp and fix the detection probe. The detection probe is in the pool and in contact with the sewage. The detection probe is connected to the probe junction box through the reinforced polyethylene tube. A cleaning valve is installed on the reinforced polyethylene tube. The cleaning valve is controlled by the SJC-209 circuit of the control box. The cleaning fluid can enter the reinforced polyethylene tube through the cleaning valve to perform the probe cleaning operation.

[0006] Furthermore, the dissolved oxygen and inverter curves are used to monitor the dissolved oxygen value and inverter operating frequency at any time in the past 7 days; the inverter high and low limits are set to ensure that the water flow is small and the dissolved oxygen is constant for a long time, and the inverter operates at an ultra-low frequency.

[0007] Furthermore, the touch screen has a high and low limit alarm for dissolved oxygen. When the dissolved oxygen exceeds the set upper and lower limits due to unexpected reasons, the PLC will output an alarm signal and the external alarm will be activated to remind the on-duty personnel to deal with it in time.

[0008] The beneficial effects of the present invention are:

[0009] The present invention provides a device for stabilizing dissolved oxygen in a sewage treatment system, comprising: a detection module, a control box, a frequency converter and an aerator. The detection module has a self-cleaning function and can be suitable for long-term effective operation in sewage. It can realize that the system operates in an "automatic" state and the PLC controls the frequency converter to start. The PLC performs PID adjustment based on the error between the dissolved oxygen set value and the actual dissolved oxygen detection value, and outputs a frequency setting signal to the frequency converter. The frequency converter ensures that the dissolved oxygen remains within a small range above and below the set value based on the frequency setting signal and the pre-set aerator speed, thereby realizing stable operation of the dissolved oxygen constant value. It can efficiently and conveniently stabilize the dissolved oxygen in water to an appropriate range, and the device can ensure long-term safe and stable operation.

[0010] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0012] Figure 1 This is a working diagram of a device for stabilizing dissolved oxygen in a sewage treatment system according to the present invention;

[0013] Figure 2 A schematic structural diagram of a detection module of the present invention;

[0014] Figure 3 It is a structural schematic diagram of the control box of the present invention;

[0015] Figure 4 This is a schematic diagram of the overall structure of a device for stabilizing dissolved oxygen in a sewage treatment system according to the present invention;

[0016] Among them: 1. Water pool; 2. Sewage; 3. Mounting frame; 4. Probe junction box; 5. Reinforced polyethylene pipe; 6. Cleaning fluid; 7. Control box; 8. Touch screen; 9. Automatic button; 10. Manual button; 11. Dissolved oxygen and inverter curves. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this embodiment have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0019] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0020] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention, and should not be understood as limiting the present invention.

[0021] In the present invention, terms such as "fixed connection," "connected," and "connection" should be interpreted broadly to mean a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediary. Relevant researchers or technicians in this field may determine the specific meanings of these terms in the present invention based on specific circumstances, and they should not be construed as limitations of the present invention.

[0022] Example 1, as Figure 1-Figure 4As shown, this embodiment provides a device for stabilizing dissolved oxygen in a sewage treatment system, including: a detection module, a control box, a frequency converter and an aerator. The detection module includes a detection probe and a meter for detecting the dissolved oxygen concentration; the control box includes a PLC for receiving dissolved oxygen concentration information, processing it to obtain dissolved oxygen and frequency converter curves, and adjusting the frequency converter operation according to the dissolved oxygen and frequency converter curves. The PLC performs PID conditioning based on the error between the dissolved oxygen set value and the actual dissolved oxygen detection value, and outputs a frequency setting signal to the frequency converter; the frequency converter ensures that the dissolved oxygen remains within a small range above and below the set value based on the frequency setting signal and the pre-set aerator speed, thereby achieving stable operation of a constant dissolved oxygen value.

[0023] Specifically, the detection module is set up and installed as follows Figure 1 As shown, Figure 1 It includes a water pool 1, sewage 2, a mounting frame 3, a probe junction box 4, a reinforced polyethylene tube 5, and a cleaning fluid 6. The mounting frame 3 is fixedly installed on the edge of the water pool 1. The mounting frame 3 installs the probe junction box 4 above the water pool 1. The water pool 1 contains sewage 2. The mounting frame 3 adopts a tubular bracket. A plurality of clamps are provided on the tubular bracket. The clamps are used to clamp and fix the detection probe. The detection probe is in the water pool 1 and contacts the sewage. One end of the detection probe is electrically connected to the probe junction box 4, and the other end of the detection probe is connected to the cleaning pipeline through the reinforced polyethylene tube 5. A cleaning valve is installed on the reinforced polyethylene tube 5. The cleaning valve is controlled by the SJC-209 circuit of the control box. The cleaning fluid 6 can enter the reinforced polyethylene tube 5 through the second valve to perform the probe cleaning operation.

[0024] Dissolved oxygen and inverter curve 11 is used to monitor the dissolved oxygen value and inverter operating frequency at any time in the past 7 days;

[0025] PID conditioning is proportional-integral-derivative control (PID conditioning for short). It forms a control deviation based on the given value and the actual output value, and linearly combines the deviation into a control quantity based on the proportion, integration and differentiation to control the controlled object.

[0026] PID conditioning utilizes a PID conditioning module, which includes a deviation calculation circuit, P, I, and D conditioning modules, a summing circuit, a zero-bias circuit, a dither signal circuit, and a power amplifier circuit. The deviation calculation circuit calculates the difference between the feedback signal and the command signal. The deviation calculation circuits for the inner and outer loops function essentially the same way.

[0027] P, I, and D conditioning modules: used to implement P conditioning, I conditioning, and D conditioning on the signal output by the deviation output circuit. The P conditioning module can be used alone, and the other two need to be combined with the P conditioning module to form PI conditioning, PD conditioning, or the three together to form PID conditioning.

[0028] Summing circuit: It is used to sum the signals after PID conditioning. The functions of the summing circuits of the inner and outer loops are basically the same.

[0029] Zero bias circuit: used to adjust the output zero position, with an adjustable range of 0 to ±10 V. The zero bias circuits of the inner and outer loops have basically the same function and are implemented using high-precision op amps.

[0030] Dither signal circuit: This circuit provides the inverter with a high-frequency, low-amplitude signal to compensate for system friction. The dither signal's amplitude and frequency can be adjusted using a potentiometer and a high-precision op amp.

[0031] Power amplifier circuit: This circuit converts the servo drive signal from voltage to current (V / I), amplifies the drive power, and ultimately outputs a current signal to drive the inverter. The current drive output signal can be adjusted to different ranges by switching the switch in the selection circuit. The circuit primarily utilizes high-current output and high-precision op amps.

[0032] The inverter has high and low limit settings. When the dissolved oxygen meter is abnormal, in order to ensure the normal operation of the air compressor and save electricity, the air compressor is set to an upper limit to ensure system stability. To ensure a small water flow and long-term constant dissolved oxygen, the inverter is operated at an ultra-low frequency. The aeration pressure is low, causing water pressure backflow and clogging the aeration head. The inverter is set to a low-limit frequency operation. Set the low-limit operation on the touch screen to make the inverter operate at the set low limit.

[0033] Dissolved oxygen high and low limit alarm: The touch screen is set with dissolved oxygen high and low limit alarm. When the dissolved oxygen exceeds the set upper and lower limits due to unexpected reasons, the PLC will output an alarm signal and the external alarm will be activated to remind the on-duty personnel to deal with it in time.

[0034] Specifically, the detection module consists of a set of Leici sewage online dissolved oxygen detection probes and a meter, which outputs the dissolved oxygen as a 4-20MA analog quantity.

[0035] Control box: PLC and touch screen group and auxiliary components. The auxiliary components include a DC24V switching power supply for the signal module, a group of alarm isolation relays, 3 groups of power switches, the dissolved oxygen value is displayed on the touch screen, and the touch screen 8 has PLC data display and setting, manual and automatic operation switching, sampling setting, inverter frequency high and low limit setting, dissolved oxygen high and low alarm setting, dissolved oxygen and inverter operation monitoring curves, etc.; Figure 3 As shown, the control box 7 is provided with a touch screen 8, an automatic button 9 and a manual button 10, and the touch screen 8 displays a dissolved oxygen and a frequency converter curve 11.

[0036] Frequency converter and aerator: The aerator can adopt the ZK37-60 model of Hudu Technology. The frequency converter ensures that the dissolved oxygen is kept within a small range above and below the set value based on the frequency given signal and the pre-set aerator speed, thus achieving stable operation of constant dissolved oxygen value.

[0037] Manual-automatic operation switching: When the probe needs maintenance, replacement, or calibration, the system is set to "manual" state. When the PLC receives no signal or an error signal, the system is in normal operation.

[0038] Working Principle: Power is turned on and the system is put into operation in "Auto" mode. The PLC controls the inverter to start. The PLC performs PID control based on the error between the set dissolved oxygen value and the actual measured dissolved oxygen value, and outputs a frequency reference signal to the inverter. Based on this frequency reference signal and the pre-set aerator speed, the inverter ensures that the dissolved oxygen value remains within a small range above and below the set value, achieving a constant dissolved oxygen value and stable operation.

[0039] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A device for stabilizing dissolved oxygen in a sewage treatment system, characterized in that: include: A detection module, a control box, a frequency converter and an aerator, wherein the detection module is connected to a first port of the control box, a second port of the control box is connected to one end of the frequency converter, and the other end of the frequency converter is connected to the aerator; The detection module includes a detection probe and a probe junction box for detecting dissolved oxygen concentration. The control box includes a PLC for receiving dissolved oxygen concentration information, processing it to obtain dissolved oxygen and inverter curves, and adjusting inverter operation according to the dissolved oxygen and inverter curves. The PLC performs PID conditioning based on the error between the dissolved oxygen set value and the actual dissolved oxygen detection value, and outputs a frequency setting signal to the inverter. The inverter ensures that the dissolved oxygen remains within a small range above and below the set value based on the frequency setting signal and the pre-set aerator speed, achieving stable operation of a constant dissolved oxygen value. The detection module comprises a mounting frame (3), a probe junction box (4), a reinforced polyethylene tube (5), and a cleaning fluid (6). The mounting frame (3) is fixedly mounted on the edge of the pool (1). The mounting frame (3) mounts the probe junction box (4) above the pool (1). The pool (1) contains sewage (2). The mounting frame (3) adopts a tubular bracket. A plurality of clamps are arranged on the tubular bracket. The clamps are used to clamp and fix the detection probe. The detection probe is in the pool (1) and contacts the sewage. The detection probe is connected to the probe junction box (4) through the reinforced polyethylene tube (5). A cleaning valve is installed on the reinforced polyethylene tube (5). The cleaning fluid (6) enters the reinforced polyethylene tube (5) through the cleaning valve to perform a probe cleaning operation. PID conditioning uses a PID conditioning module: including deviation calculation circuit, P, I, D conditioning module, summing circuit, zero bias circuit, dither signal circuit and power amplifier circuit; Deviation calculation circuit: used to calculate the difference between the feedback signal and the command signal; P, I, D conditioning module: used to implement P conditioning, I conditioning and D conditioning on the signal output by the deviation output circuit; Summing circuit: used to realize summation processing of each signal after PID conditioning; Zero bias circuit: used to adjust the output zero position, the adjustable range is 0 ~ ± 10V; Dither signal circuit: provides a high-frequency, low-amplitude signal to compensate for system friction; the amplitude and frequency of the dither signal are adjusted by a potentiometer and implemented using an op amp; Power amplifier circuit: used to realize the voltage-current conversion of the servo drive signal and the drive power amplification, and finally output the current signal to drive the inverter.

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