Flocculation basin control device for water purification plant

Abstract

The utility model relates to the field of water purification treatment, in particular to a control device for a flocculation basin of a water purification plant, which comprises a floating ball liquid level meter, a frequency converter I, a frequency converter II, a thermal resistor, an acquisition plate and a control unit, the floating ball liquid level meter is arranged in the flocculation basin, and the thermal resistor is arranged on a water inlet pipe; the water inlet pump and the water outlet pump are driven by corresponding frequency converters, the thermal resistor is connected with the acquisition board, and the gate valve is connected with the main loop; and the main loop, the frequency converter, the acquisition board and the floating ball liquid level meter are respectively connected with the control unit. The utility model has the advantages that the water inlet pump and the water outlet pump of the flocculation section are driven by the frequency converter, the communication card is arranged in the frequency converter, and an operator adjusts the rotating speed of the water inlet pump and the water outlet pump through the potentiometer arranged on the HIM human-computer interaction screen, so that the electric energy loss is reduced; a built-in communication card of the frequency converter is used for transmitting operation states, such as operation states and fault states, of the water inlet pump and the water outlet pump to the HIM man-machine interaction screen, and unified monitoring of a central control room is facilitated.

Description

Technical Field

[0001] The utility model relates to the field of water purification and treatment, in particular to a flocculation tank control device for a water purification plant. Background Art

[0002] The flocculation tank is a key step in the water treatment process. It is mainly used to aggregate suspended particles in the water into flocs by adding flocculants, thereby accelerating sedimentation and achieving solid-liquid separation. Currently, the control of the flocculation tank mainly relies on manual operation, which has the following technical defects:

[0003] 1. Energy efficiency issues:

[0004] The inlet and outlet pumps in the flocculation section are usually operated in a direct start mode, lacking adjustment of the pumps, resulting in energy waste and high operating costs;

[0005] 2. Liquid level monitoring relies on manual labor:

[0006] The liquid level of the flocculation tank is usually monitored by a liquid level gauge, which requires manual inspection and data recording at regular intervals. This is prone to inaccurate data recording, delays, or missed inspections, affecting the timeliness and reliability of gate valve control.

[0007] 3. Insufficient temperature collection accuracy:

[0008] The temperature collection accuracy of the water inlet pipe is low, which affects the precise adjustment of the subsequent gate valve opening, and thus affects the flocculation effect and overall water treatment efficiency. Utility Model Content

[0009] The utility model aims to provide a flocculation tank control device for a water purification plant, which does not require manual inspection and is centrally monitored by a central control room.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0011] A water purification plant flocculation tank control device includes a gate valve, an inlet pump, and an outlet pump. The inlet pump is arranged on an inlet pipe, and the outlet pump is arranged on an outlet pipe. The inlet pipe is connected to the upper portion of one side of the flocculation tank, and the outlet pipe is connected to the upper portion of the other side of the flocculation tank. The flocculation tank is provided with a gate valve, and also includes a float level gauge, a first frequency converter, a second frequency converter, a thermal resistor, a data acquisition board, and a control unit. The float level gauge is arranged in the flocculation tank, and the thermal resistor is arranged on the inlet pipe.

[0012] The water inlet pump and outlet pump are driven by the corresponding frequency converter, the thermal resistor is connected to the acquisition board, and the gate valve is connected to the main circuit;

[0013] The main circuit, frequency converter, acquisition board and float level gauge are connected to the control unit respectively.

[0014] The acquisition board includes a protection circuit, a filtering circuit, an analysis circuit, a switching circuit, and an acquisition circuit. The input end of the protection circuit is connected to the thermal resistor through a port, the output end of the protection circuit is connected to the input end of the filtering circuit, the output end of the filtering circuit is connected to the input end of the analysis circuit, the output end of the analysis circuit is connected to the input end of the acquisition circuit, and the output end of the acquisition circuit is connected to the control unit.

[0015] The protection circuit includes a transient diode D, a varistor R, and a discharge tube V. The first input terminal of the protection circuit is connected to one end of the discharge tube V and one end of the varistor R, respectively. The second input terminal of the protection circuit is connected to the other end of the discharge tube V and the other end of the transient diode D, respectively. The second input terminal of the protection circuit is grounded.

[0016] The filtering circuit includes a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, a filter chip U1, and an operational amplifier 1. The resistor R1, the capacitor C1, and the capacitor C2 constitute a first-level π-type RC filtering circuit, and the resistor R2 and the capacitor C3 constitute a second-level RC filtering circuit. The input pin in of the filter chip U1 is connected to the input terminal 1 of the filter circuit, the output pin out of the filter chip U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the input terminal of the operational amplifier 1, the output terminal of the operational amplifier 1 is connected to one end of the resistor R2, the other end of the capacitor C3, the other end of the capacitor C1, and the other end of the capacitor C2 are connected to the input terminal 2 of the filter circuit, and the input terminal 2 of the filter circuit is grounded.

[0017] The analysis circuit includes an operational amplifier 2 and a signal processing chip U2. The input pin in of the signal processing chip U2 is connected to the input end of the analysis circuit, the reference end of the signal processing chip U2 is respectively connected to the output end of the operational amplifier 2, and the output pin out of the signal processing chip U2 is connected to the output end of the analysis circuit.

[0018] The switching circuit includes a channel switching chip U3 and a coprocessor U4. The input pin in of the channel switching chip U3 and the pin adc of the coprocessor U4 are both connected to the input end of the switching circuit. The pins io1, io2, and io3 of the coprocessor U4 are respectively connected to the channel switching chip U3. The output pins out1, out2, and out3 of the channel switching chip U3 are connected to the output end of the switching circuit.

[0019] The acquisition circuit includes an analog-to-digital converter, the input end of the analog-to-digital converter is connected to the input end of the acquisition circuit, and the output end of the analog-to-digital converter is connected to the control unit;

[0020] The main circuit includes a reversing contactor and an overheating relay, a forward contactor, and a circuit breaker connected to the gate valve in sequence. The main contacts of the forward contactor are connected between the three-phase AC power supply and the gate valve to form a forward connection mode. The main contacts of the reversing contactor are connected between the three-phase AC power supply and the gate valve to form a reversing connection mode. The coils of the forward contactor and the reversing contactor are respectively connected to the control unit.

[0021] The digital input terminals of the inverter are respectively connected to the normally open contacts of the relay group, the analog output terminals of the inverter are connected to the input terminals of the isolation barrier, the output terminals of the isolation barrier are connected to the control unit, and the inverter is connected to the control unit through a built-in communication card.

[0022] The control unit includes an analog input module, a digital output module, and a communication module. The communication module is connected to the frequency converter through a built-in communication card. The analog input module is connected to the float level meter, the acquisition board, and the isolation barrier through ports. The digital output module is connected to the coil of the relay group, the coil of the forward contactor, and the coil of the reverse contactor.

[0023] The flocculation tank is divided into several vertical shafts by partition walls. Water holes are opened at the upper and lower parts of the vertical shafts in the order of water flow; each vertical shaft is equipped with a corresponding float level gauge; the gate valve is a long-stem gate valve, and a long-stem gate valve is installed in each vertical shaft. The actuator of each long-stem gate valve is set above the flocculation tank.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. The inlet and outlet pumps in the flocculation section are driven by a frequency converter with a built-in communication card. Operators adjust the speed of the inlet and outlet pumps via potentiometers on the HIM human-machine interface screen to reduce power loss. The built-in communication card in the frequency converter is used to transmit the operating status of the inlet and outlet pumps, such as operating status and fault status, to the HIM human-machine interface screen, facilitating unified monitoring in the central control room.

[0026] 2. The float level gauge in the shaft transmits the data to the HIM human-machine interactive screen through the analog input module. The HIM human-machine interactive screen is equipped with an over-limit alarm prompt, which facilitates data monitoring and eliminates the need for manual regular inspections and data recording, saving time and effort.

[0027] 3. Use the acquisition board to improve the temperature acquisition accuracy of the water inlet pipe, ensure the linearity of temperature acquisition, and provide timely feedback to the control unit, making the control system more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the control structure diagram of the flocculation tank in the water purification plant.

[0029] Figure 2This is the schematic diagram of the inverter drive for the flocculation tank in a water purification plant.

[0030] Figure 3 This is the network diagram of the inverter for the flocculation tank in a water purification plant.

[0031] Figure 4 This is the schematic diagram of the gate valve.

[0032] Figure 5 The control unit principle Figure 1 .

[0033] Figure 6 The control unit principle Figure 2 .

[0034] Figure 7 The control unit principle Figure 3 .

[0035] Figure 8 This is the schematic diagram of the acquisition board.

[0036] Figure 9 This is the structural diagram of the flocculation tank in the water purification plant.

[0037] In the figure: 1. Water inlet pump; 2. Water outlet pump; 3. Gate valve; 4. Thermal resistor; 5. Water inlet pipe; 6. Water outlet pipe; 7. Partition wall; 8. Water passage; 9. Mud discharge hopper; 10. Turbidity sensor. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to the accompanying drawings. However, it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0039] The following examples are implemented under the premise of the technical solution of the present utility model, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present utility model is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0040] Example 1:

[0041] A flocculation tank control device for a water purification plant, see Figure 9The flocculation tank is divided into four vertical shafts by a partition wall 7. Water holes 8 are opened at the upper and lower parts of the vertical shafts in sequence according to the water flow order; each vertical shaft is provided with a corresponding float level gauge for detecting the liquid level in the corresponding vertical shaft; each vertical shaft is provided with a gate valve 3, which is a long-rod gate valve 3, and the actuator of each long-rod gate valve 3 is arranged above the flocculation tank; a mud bucket 9 and a mud discharge pipe are provided at the bottom of each vertical shaft for discharging the collected mud at the bottom of the vertical shaft; an inlet pipe 5 is connected to the upper part of one side of the flocculation tank, and an outlet pipe 6 is connected to the upper part of the other side of the flocculation tank. The inlet pump 1 is arranged on the inlet pipe 5, and the outlet pump 2 is arranged on the outlet pipe 6; a thermal resistor 4 and a turbidity sensor 10 are provided on the inlet pipe 5, and the thermal resistor 4 is a four-wire system.

[0042] The flocculation tank control device of the water purification plant also includes frequency converter 1, frequency converter 2, acquisition board, and control unit. The control unit is PLC. The inlet pump 1 and the outlet pump 2 are driven by the corresponding frequency converter. Figure 2 、 Figure 3 , thermal resistor 4 is connected to the acquisition board; gate valve 3 is connected to the main circuit, see Figure 4 .

[0043] See Figure 8 The acquisition board includes a protection circuit, a filtering circuit, an analysis circuit, a switching circuit, and an acquisition circuit. The protection circuit includes a transient diode D, a varistor R, and a discharge tube V, which are used to suppress the destructive interference of high voltage and high current superimposed on the input signal line and protect the normal operation of other internal circuits; terminals 1-2 of the thermal resistor 4 are respectively connected to one end of the discharge tube V and one end of the varistor R, and terminals 1-4 of the thermal resistor 4 are respectively connected to the other end of the discharge tube V and the other end of the transient diode D, and the second input terminal of the protection circuit is grounded; terminal 1-1 of the thermal resistor 4 is connected to the constant current source of the analog-to-digital converter AD7124-4, and terminal 1-3 of the thermal resistor 4 is connected to another constant current source of the analog-to-digital converter AD7124-4.

[0044] The filtering circuit includes resistor R1, resistor R2, capacitor C1, capacitor C2, capacitor C3, filter chip U1, and operational amplifier 1. Operational amplifier 1 is used for high-frequency signal filtering, and filter chip U1 is used to filter out industrial frequency interference signals. Resistor R1, capacitor C1, and capacitor C2 form a first-level π-type RC filtering circuit. Operational amplifier 1 uses chip OPA277, and filter chip U1 uses chip UAF42. Resistor R2 and capacitor C3 form a second-level RC filtering circuit. The input pin in of filter chip U1 is connected to the other end of varistor R, and the output pin out of filter chip U1 is connected to one end of resistor R1. The other end of resistor R1 is connected to input port 3-3 of operational amplifier 1, output port 3-6 of operational amplifier 1 is connected to one end of resistor R2, and output port 3-6 of operational amplifier 1 is connected to input port 3-2 of operational amplifier 1. The other end of capacitor C3, the other end of capacitor C1, and the other end of capacitor C2 are connected to input terminal 2 of the filtering circuit, and input terminal 2 of the filtering circuit is grounded.

[0045] The analysis circuit includes an operational amplifier 2 and a signal processing chip U2, which are used to perform preliminary and rapid analysis and screening on the input signal of the thermal resistor 4. When the input signal mutates or the input signal changes in a sluggish manner, the erroneous signal will be removed. If a large mutated signal is input, the input signal will be quickly disconnected to ensure that other internal devices and the subsequent circuit will not collect the mutated signal, thereby ensuring that the PLC will not produce erroneous control. The operational amplifier 2 is used to generate a standard voltage value for comparing the mutated voltage. The signal processing chip U2 is used to compare the input signal with the standard voltage value and quickly switch the input signal channel to avoid damaging the subsequent circuit. The input pin in of the signal processing chip U2 and the other end of the resistor R2, and the reference end of the signal processing chip U2 are respectively connected to the input port 4-2 of the operational amplifier 2 and the output port 4-6 of the operational amplifier 2, and the input port 4-3 of the operational amplifier 2 is connected to the power supply VCC.

[0046] The switching circuit includes a channel switching chip U3 and a coprocessor U4. The channel switching chip U3 adopts an MCU, and the coprocessor U4 adopts an analog switch chip. The coprocessor U4 mainly analyzes the input signal value of the thermal resistor 4 based on the value collected by the ADC, and controls the channel switching chip U3 through the I0 port based on the defined measurement range, switches the input signal of the thermal resistor 4 to different channels, and inputs it into different sampling channels of the analog-to-digital converter. At the same time, the coprocessor U4 can also be used to analyze whether the input signal of the thermal resistor 4 is abnormal, such as long-term unchanged or sudden change, and report it to the PLC system through the serial port of the coprocessor. At the same time, the erroneous input signal is cut off to protect the subsequent circuit; the input pin in of the channel switching chip U3 and the pin adc of the coprocessor U4 are connected to the output pin out of the signal processing chip U2, and the pins io1, io2, and io3 of the coprocessor U4 are respectively connected to the channel switching chip U3.

[0047] The acquisition circuit includes an analog-to-digital converter, which uses the AD7124-4 chip. The analog-to-digital converter is used to perform analog-to-digital conversion on the input signal of the input thermal resistor 4. The input end of the analog-to-digital converter is connected to the output pins out1, out2, and out3 of the channel switching chip U3, and the output end of the analog-to-digital converter is connected to the analog input module of the PLC.

[0048] See Figure 4 The main circuit includes a reverse contactor KM2 and an overheating relay FR, a forward contactor KM1, and a circuit breaker QK connected in sequence to the gate valve 3. The main contacts of the forward contactor KM1 are connected between the three-phase AC power supply and the gate valve 3 to form a forward connection mode. The main contacts of the reverse contactor KM2 are connected between the three-phase AC power supply and the gate valve 3 to form a reverse connection mode. The coils of the forward contactor KM1 and the reverse contactor KM2 are respectively connected to the PLC.

[0049] The digital input terminals of the inverter are respectively connected to the normally open contacts of relays ka1~ka5, the analog output terminals of the inverter are connected to the input terminals of the isolation barrier, and the output terminals of the isolation barrier are connected to the PLC to prevent the high-frequency noise of the inverter from being transmitted to the PLC through the analog signal, ensuring the purity of the analog signal. The isolation barrier is used to isolate interference signals. The inverter is connected to the PLC through a built-in communication card.

[0050] See Figure 1 、 Figure 5 、 Figure 6 、 Figure 7,PLC includes CPU module, analog input module, digital input module, digital output module, communication module 1, communication module 2, CPU module, analog input module, digital input module, digital output module, communication module 1, communication module 2 are connected through ports, communication module 1 is connected to the engineer station in the central control room, the engineer station is equipped with an HMI human-computer interaction screen, and the data information of the flocculation tank is transmitted to the HMI human-computer interaction screen through communication module 1, which is convenient for unified monitoring; communication module 2 is connected to the inverter through a built-in communication card, see Figure 4 , used to transmit the operating signal of the inverter to the HMI human-machine interaction screen; the analog input module is connected to the float level gauge, acquisition board, and isolation barrier through ports respectively, and is used to transmit the current signals of the float level gauge, thermal resistor 4, and inverter to the HMI human-machine interaction screen. The digital output module is connected to the coils of relays ka1~ka5, the coil of forward contactor KM1, and the coil of reverse contactor KM2 respectively. Relays ka1~ka5 are used by the PLC to send low speed, high speed, forward, ready, and fault reset commands to the inverter respectively; the normally open auxiliary contacts of the forward contactor KM1 and the normally open auxiliary contacts of the reverse contactor KM2 of each gate valve 3 are connected to the digital input module through ports respectively, and are used to transmit the forward operation information and reverse operation information of each gate valve 3 to the HMI human-machine interaction screen.

[0051] Working process:

[0052] The water inlet pump and the water outlet pump adjust the speed of the corresponding frequency converter according to the float level gauge installed in the vertical shaft; the raw water temperature of the water inlet pipe collected by the thermal resistor and the turbidity data collected by the turbidity sensor are fed back to the PLC, and the gate valve opening is adjusted in real time. When the turbidity of the raw water is high turbidity, the flocculation time can be controlled by lowering the gate valve at the bottom water hole and raising the gate valve at the top water hole; when the gate valve is open and the turbidity of the raw water is low temperature and low turbidity, the flocculation time can be controlled by raising the gate valve at the bottom water hole and lowering the gate valve at the top water hole; when the gate valve is open and the turbidity of the raw water is neither low temperature and low turbidity nor high turbidity, the flocculation time can be controlled by only raising the gate valve at the bottom water hole or only lowering the gate valve at the top water hole.

[0053] The inlet pump and outlet pump of the flocculation section of the utility model are driven by a frequency converter with a built-in communication card. The operator adjusts the rotation speed of the inlet pump and the outlet pump through the potentiometer provided on the HIM human-machine interaction screen to reduce power loss; the built-in communication card of the frequency converter is used to transmit the operating status of the inlet pump and the outlet pump, such as the operating status and fault status, to the HIM human-machine interaction screen, so as to facilitate unified monitoring by the central control room; the float level gauge in the vertical shaft transmits the information to the HIM human-machine interaction screen through the analog input module, and the HIM human-machine interaction screen is provided with an over-limit alarm prompt, which facilitates data monitoring and eliminates the need for manual regular inspections and data recording, saving time and effort; the acquisition board is used to improve the temperature acquisition accuracy of the water inlet pipe, ensure the linearization of temperature acquisition, and provide timely feedback to the control unit, making the control system more stable.

Claims

1. A flocculation tank control device for a water purification plant, comprising a gate valve, an inlet pump, and an outlet pump, wherein the inlet pump is arranged on an inlet pipe, the outlet pump is arranged on an outlet pipe, the inlet pipe is connected to the upper portion of one side of the flocculation tank, and the outlet pipe is connected to the upper portion of the other side of the flocculation tank, and the flocculation tank is provided with a gate valve, characterized in that: It also includes a float level gauge, a frequency converter 1, a frequency converter 2, a thermal resistor, a collection board, and a control unit. The float level gauge is set in the flocculation tank, and the thermal resistor is set on the water inlet pipe. The water inlet pump and outlet pump are driven by the corresponding frequency converter, the thermal resistor is connected to the acquisition board, and the gate valve is connected to the main circuit; The main circuit, frequency converter, acquisition board and float level gauge are connected to the control unit respectively.

2. A water purification plant flocculation tank control device according to claim 1, characterized in that: The acquisition board includes a protection circuit, a filtering circuit, an analysis circuit, a switching circuit, and an acquisition circuit. The input end of the protection circuit is connected to the thermal resistor through a port, the output end of the protection circuit is connected to the input end of the filtering circuit, the output end of the filtering circuit is connected to the input end of the analysis circuit, the output end of the analysis circuit is connected to the input end of the acquisition circuit, and the output end of the acquisition circuit is connected to the control unit.

3. A water purification plant flocculation tank control device according to claim 2, characterized in that: The protection circuit includes a transient diode D, a varistor R, and a discharge tube V. The first input terminal of the protection circuit is respectively connected to one end of the discharge tube V and one end of the varistor R. The second input terminal of the protection circuit is respectively connected to the other end of the discharge tube V and the other end of the transient diode D. The second input terminal of the protection circuit is grounded.

4. A flocculation tank control device for a water purification plant according to claim 2, characterized in that: The filtering circuit includes a resistor R1, a resistor R2, a capacitor C1, a capacitor C2, a capacitor C3, a filter chip U1, and an operational amplifier 1. The resistor R1, the capacitor C1, and the capacitor C2 form a first-level π-type RC filtering circuit, and the resistor R2 and the capacitor C3 form a second-level RC filtering circuit. The input pin in of the filter chip U1 is connected to the input terminal 1 of the filtering circuit, the output pin out of the filter chip U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the input terminal of the operational amplifier 1, the output terminal of the operational amplifier 1 is connected to one end of the resistor R2, the other end of the capacitor C3, the other end of the capacitor C1, and the other end of the capacitor C2 are connected to the input terminal 2 of the filtering circuit, and the input terminal 2 of the filtering circuit is grounded.

5. A flocculation tank control device for a water purification plant according to claim 2, characterized in that: The analysis circuit includes an operational amplifier 2 and a signal processing chip U2. The input pin in of the signal processing chip U2 is connected to the input end of the analysis circuit, the reference end of the signal processing chip U2 is respectively connected to the output end of the operational amplifier 2, and the output pin out of the signal processing chip U2 is connected to the output end of the analysis circuit.

6. A water purification plant flocculation tank control device according to claim 2, characterized in that: The switching circuit includes a channel switching chip U3 and a coprocessor U4. The input pin in of the channel switching chip U3 and the pin adc of the coprocessor U4 are both connected to the input end of the switching circuit. The pins io1, io2, and io3 of the coprocessor U4 are respectively connected to the channel switching chip U3. The output pins out1, out2, and out3 of the channel switching chip U3 are connected to the output end of the switching circuit.

7. A flocculation tank control device for a water purification plant according to claim 2, characterized in that: The acquisition circuit includes an analog-to-digital converter, the input end of the analog-to-digital converter is connected to the input end of the acquisition circuit, and the output end of the analog-to-digital converter is connected to the control unit; The main circuit includes a reversing contactor and an overheating relay, a forward contactor, and a circuit breaker connected to the gate valve in sequence. The main contacts of the forward contactor are connected between the three-phase AC power supply and the gate valve to form a forward connection mode. The main contacts of the reversing contactor are connected between the three-phase AC power supply and the gate valve to form a reverse connection mode. The coils of the forward contactor and the reverse contactor are respectively connected to the control unit.

8. The flocculation tank control device for a water purification plant according to claim 1, characterized in that: The digital input terminals of the frequency converter are respectively connected to the normally open contacts of the relay group, the analog output terminals of the frequency converter are connected to the input terminals of the isolation barrier, the output terminals of the isolation barrier are connected to the control unit, and the frequency converter is connected to the control unit via a built-in communication card.

9. The flocculation tank control device for a water purification plant according to claim 1, characterized in that: The control unit includes an analog input module, a digital output module, and a communication module. The communication module is connected to the frequency converter through a built-in communication card. The analog input module is connected to the float level meter, the acquisition board, and the isolation fence through ports. The digital output module is connected to the coil of the relay group, the coil of the forward contactor, and the coil of the reverse contactor.

10. The flocculation tank control device for a water purification plant according to claim 1, characterized in that: The flocculation tank is divided into several vertical shafts by partition walls, and water holes are opened at the upper and lower parts of the vertical shafts in sequence according to the water flow order; each vertical shaft is provided with a corresponding float level gauge; the gate valve is a long-stem gate valve, and a long-stem gate valve is provided in each vertical shaft, and the actuator of each long-stem gate valve is arranged above the flocculation tank.

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