Universal liquid level controller

Abstract

The utility model relates to a universal liquid level controller, and belongs to the technical field of automatic liquid level control. According to the technical scheme, an analog-to-digital conversion circuit (102) comprises an emitter follower circuit composed of a triode BG1 and a resistor R1 and a follower circuit composed of a triode BG2, a resistor R2 and a capacitor C2, an upper electrode (11) of a liquid level sensor (101) is connected with the input end of the emitter follower circuit, and the output end of the emitter follower circuit is connected with a pin 6 of an NE555 chip; a middle electrode (12) of the liquid level sensor (101) is connected with the input end of the follower circuit, the output end of the follower circuit is connected with a second pin of the NE555 chip, and a lower electrode (13) of the liquid level sensor (101) is connected with power supply voltage. An analog-to-digital conversion circuit and a liquid level sensor in the prior art are replaced by a simple circuit, the design is simple, the number of components is small, control is sensitive, and cost is reduced.

Description

Technical Field

[0001] The utility model relates to a universal liquid level controller, belonging to the technical field of liquid level automatic control. Background Art

[0002] Liquid level control is used in various fields, especially in automatic water supply and automatic water replenishment control technology, which is favored by users. For example, the rooftop pool in high-rise buildings, the underground pool in large hotels, the water tower standing on the ground and the treatment of underground sewage pools are inseparable from the liquid level controller. Most of the liquid level controllers in the existing technology use liquid level sensors to detect the liquid level, and then automatically control the control system after analog-to-digital conversion (A / D), such as: Chinese patent CN201520365400.2, named "A water tank liquid level balance control circuit" and CN202023323869.X, named "A water tank liquid level controller", etc. Due to different use environments, the existing technology has inconsistent use of sensors, and there are disadvantages such as complex analog-to-digital conversion (A / D) circuit design circuits, many devices used and high costs. In addition, the liquid level sensor structure of the existing technology is complex and the cost is high. Utility Model Content

[0003] The utility model aims to provide a universal liquid level controller, which replaces the analog-to-digital conversion (A / D) circuit and liquid level sensor of the prior art with a simple circuit, has a simple design, few components, sensitive control, reduces costs, and solves the above-mentioned problems existing in the background technology.

[0004] The technical solution of the utility model is:

[0005] A universal liquid level controller comprises a liquid level sensor, an analog-to-digital conversion circuit, a NE555 circuit, a switch circuit, an actuator and a power supply connected in sequence, wherein the NE555 chip of the NE555 circuit is an 8-pin time-based integrated circuit; the liquid level sensor is a three-electrode sensor, which comprises an upper electrode, a middle electrode and a lower electrode, and the upper electrode, the middle electrode and the lower electrode are respectively arranged at the high liquid level, the low liquid level and the bottom of the water tank; the analog-to-digital conversion circuit comprises an emitter follower circuit composed of a transistor BG1 and a resistor R1 and a transistor BG2, a resistor R 2 and capacitor C2, the upper electrode of the liquid level sensor is connected to the input end of the emitter follower circuit, the output end of the emitter follower circuit is connected to pin 6 of the NE555 chip, the middle electrode of the liquid level sensor is connected to the input end of the follower circuit, the output end of the follower circuit is connected to pin 2 of the NE555 chip, and the lower electrode of the liquid level sensor is connected to the power supply voltage VCC through resistor R0; pin 3 of the NE555 chip is connected to the input end of the switch circuit, the output end of the switch circuit drives the actuator, and the actuator drives the water supply solenoid valve connected to the water tank.

[0006] The liquid level sensor, NE555 circuit, switch circuit, actuator and power supply are all common electronic devices known in the art.

[0007] Furthermore, the three electrodes of the liquid level sensor are three plastic-insulated copper wires, the first plastic-insulated copper wire is exposed at the bottom of the water tank as a lower electrode, the second plastic-insulated copper wire is exposed at the low liquid level of the water tank as a middle electrode, and the third plastic-insulated copper wire is exposed at the high liquid level of the water tank as an upper electrode. The liquid level sensor composed of three plastic-insulated copper wires is simple, practical, and highly reliable.

[0008] Furthermore, the output drive of the actuator is connected to a relay, and the normally open contact of the relay is connected in series in the power supply circuit of the water supply solenoid valve.

[0009] With the utility model, when the liquid level in the water tank is lower than the low liquid level point b, the output of the follower circuit composed of the transistor BG2, the resistor R2 and the capacitor C2 generates a low pulse, the peak voltage of which is less than 1 / 3 of the power supply voltage VCC, thereby triggering the 2nd foot of the NE555 chip, setting the trigger in the NE555 chip to "1", driving the relay of the actuator to pull in, the normally open contact to close, the water supply solenoid valve to work, and water to the water tank. When the water level in the water tank rises to the high liquid level point C, a high level is generated on the base of the transistor BG1, and the emitter follower circuit composed of the transistor BG1 and the resistor R1 instantly generates a high pulse, the pulse peak value> 2 / 3 of the power supply voltage VCC is input to the 6th foot of the NE555 chip, so that the comparator of the NE555 chip outputs a negative pulse, and the trigger RS ​​is set to "0", so that the relay of the actuator is released, the normally open contact is opened, the water supply solenoid valve stops working, and the water tank is stopped from being filled. After a period of time, the liquid level in the water tank gradually decreases. When the water level drops to the low liquid level point b, the base voltage of transistor BG2 changes from high potential to low level, causing the emitter of transistor BG2 to output a low pulse instantly, thereby triggering pin 2 of the NE555 chip, setting its internal trigger RS ​​to "1", driving the actuator's relay to close, closing the normally open contact, and working the water supply solenoid valve to fill the water tank with water. This cycle repeats.

[0010] The utility model has a wide range of applications and can be called a universal liquid level controller. Its analog-to-digital conversion (A / D) circuit uses discrete components to form a separate circuit, and has a simple and novel design, high stability, and strong anti-interference ability.

[0011] The utility model has the beneficial effects of replacing the analog-to-digital conversion (A / D) circuit and the liquid level sensor of the prior art with a simple circuit, with simple design, few components, sensitive control and reduced cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1This is a circuit diagram of an embodiment of the utility model;

[0013] Figure 2 It is a control block diagram of an embodiment of the utility model;

[0014] Figure 3 This is a schematic diagram of the NE555 circuit of the utility model embodiment;

[0015] In the figure: liquid level sensor 101, analog-to-digital conversion circuit 102, NE555 circuit 103, switch circuit 104, actuator 105, power supply 106, water tank 107, water supply solenoid valve 108, relay 109, normally open contact 110, upper electrode 11, middle electrode 12, lower electrode 13, voltage divider 14, comparator 15, trigger RS16, output stage 17, discharge switch 18. DETAILED DESCRIPTION

[0016] The present invention will be further described below through embodiments in conjunction with the accompanying drawings.

[0017] Combined with Figure 1-3 The present embodiment provides a universal liquid level controller, comprising a liquid level sensor 101, an analog-to-digital conversion circuit 102, a NE555 circuit 103, a switch circuit 104, an actuator 105 and a power supply 106 connected in sequence, wherein the NE555 chip of the NE555 circuit 103 is an 8-pin time-based integrated circuit; the liquid level sensor 101 is a three-electrode sensor, which includes an upper electrode 11, a middle electrode 12 and a lower electrode 13, and the upper electrode 11, the middle electrode 12 and the lower electrode 13 are respectively arranged at the high liquid level, the low liquid level and the bottom of the water tank 107; the analog-to-digital conversion circuit 102 comprises an emitter follower circuit composed of a transistor BG1 and a resistor R1 and a transistor The follower circuit consists of a tube BG2, a resistor R2 and a capacitor C2, the upper electrode 11 of the liquid level sensor 101 is connected to the input end of the emitter follower circuit, the output end of the emitter follower circuit is connected to the 6th pin of the NE555 chip, the middle electrode 12 of the liquid level sensor 101 is connected to the input end of the follower circuit, the output end of the follower circuit is connected to the 2nd pin of the NE555 chip, and the lower electrode 13 of the liquid level sensor 101 is connected to the power supply voltage Vcc through the resistor R0; the 3rd pin of the NE555 chip is connected to the input end of the switch circuit 104, the output end of the switch circuit 104 drives the actuator 105, and the actuator 105 drives the water supply solenoid valve 108 connected to the water tank 107.

[0018] The three electrodes of the liquid level sensor 101 are three plastic-insulated copper wires, the first plastic-insulated copper wire is exposed at the bottom of the water tank 107 as the lower electrode 13, the second plastic-insulated copper wire is exposed at the low liquid level of the water tank 107 as the middle electrode 12, and the third plastic-insulated copper wire is exposed at the high liquid level of the water tank 107 as the upper electrode 11. The liquid level sensor composed of three plastic-insulated copper wires is simple, practical and highly reliable.

[0019] The output drive of the actuator 105 is connected to a relay 109 , and a normally open contact 110 of the relay is connected in series to a power supply circuit of the water supply solenoid valve 108 .

[0020] The middle electrode 12 is installed at any position between the high liquid level and the bottom of the water tank 107 and is adjusted according to the height of the water tank.

[0021] The NE555 circuit 103 is a circuit known in the art and includes a NE555 chip, which is composed of a voltage divider 14, a comparator 15, a trigger RS16, an output stage 17 and a discharge switch 18 connected in sequence.

[0022] In the embodiment, when the liquid level in the water tank 107 is lower than the low liquid level point b, the follower circuit composed of the transistor BG2, the resistor R2 and the capacitor C2 outputs a short pulse, whose peak voltage is <1 / 3 of the power supply voltage Vcc, thereby triggering pin 2 of the NE555 chip, setting the trigger in the NE555 chip to "1", driving the relay 109 of the actuator 105 to attract, the normally open contact 110 to close, and the water supply solenoid valve 108 to work, filling the water tank 107 with water. When the water level in the water tank 107 rises to the high liquid level point C, a high level is generated at the base of the transistor BG1, and the emitter follower circuit composed of the transistor BG1 and the resistor R1 instantly generates a high pulse. The pulse peak value > 2 / 3 of the power supply voltage Vcc is input to the 6th pin of the NE555 chip, causing the comparator of the NE555 chip to output a negative pulse, setting the trigger RS ​​to "0", thereby releasing the relay 109 of the actuator 105, opening the normally open contact 110, and stopping the water supply solenoid valve 108 from working, and stopping filling the water tank 107 with water. After a period of time, the liquid level in the water tank 107 gradually decreases. When the water level drops to the low liquid level point b, the base voltage of the transistor BG2 changes from high potential to low level, causing the emitter of the transistor BG2 to instantly output a low pulse, thereby triggering pin 2 of the NE555 chip, setting its internal trigger RS ​​to "1", driving the relay 109 of the actuator 105 to close, the normally open contact 110 to close, and the water supply solenoid valve 108 to work, filling the water tank 107 with water. This cycle repeats.

[0023] Refer to the attached Figure 3The circuit is composed of five parts: voltage divider 14, comparator 15, trigger RS16, output stage 17 and discharge switch 18. The NE555 chip has 8 pins, and the utility model does not need to use pin 7, so pin 7 can be left floating. The voltage divider 14 of the NE555 circuit 103 is composed of three 5KΩ resistors R1, R2 and R3, so the NE555 chip is called NE555. Resistor R1 obtains 1 / 3 of the power supply voltage VCC, resistor R2 obtains 2 / 3 of the power supply voltage Vcc, and resistor R3 obtains the entire power supply voltage VCC.

[0024] The comparator 15 includes comparator A1 and comparator A2. When TR input is a negative pulse of <1 / 3 power supply voltage VCC, comparator A2 outputs a negative pulse, triggering trigger RS16, and the output level is low, so that the output Uo of inverter F becomes high (i.e., pin 3 of NE555 chip), and the high level starts the actuator and water supply solenoid valve 108 to work, and fill the water tank (including water tower or pool) with water until the liquid level in the water tank rises to the high liquid level point C. When the 6-pin input of NE555 chip is a high pulse and the instantaneous pulse voltage is >2 / 3 power supply voltage VCC, comparator A1 outputs a low pulse, which is triggered by trigger RS16, so that the output of trigger RS16 is high, and through inverter F, pin 3 of NE555 chip outputs a low level, so that the actuator and water supply solenoid valve are closed, and the water supply to the tank is stopped. At this time, the liquid level in the water tank rises to the highest level.

Claims

1. A universal liquid level controller, characterized in that: The invention comprises a liquid level sensor (101), an analog-to-digital conversion circuit (102), a NE555 circuit (103), a switch circuit (104), an actuator (105) and a power supply (106) which are connected in sequence. The NE555 chip of the NE555 circuit (103) is an 8-pin time-based integrated circuit. The liquid level sensor (101) is a three-electrode sensor, which comprises an upper electrode (11), a middle electrode (12) and a lower electrode (13). The upper electrode (11), the middle electrode (12) and the lower electrode (13) are respectively arranged at a high liquid level, a low liquid level and the bottom of a water tank (107). The analog-to-digital conversion circuit (102) comprises an emitter follower circuit composed of a transistor BG1 and a resistor R1 and a transistor BG2, A follower circuit is formed of a resistor R2 and a capacitor C2, wherein the upper electrode (11) of the liquid level sensor (101) is connected to the input end of the emitter follower circuit, the output end of the emitter follower circuit is connected to pin 6 of a NE555 chip, the middle electrode (12) of the liquid level sensor (101) is connected to the input end of the follower circuit, the output end of the follower circuit is connected to pin 2 of the NE555 chip, and the lower electrode (13) of the liquid level sensor (101) is connected to a power supply voltage VCC via a resistor R0; pin 3 of the NE555 chip is connected to the input end of a switch circuit (104), the output end of the switch circuit (104) drives an actuator (105), and the actuator (105) drives a water supply solenoid valve (108) connected to a water tank (107).

2. A universal liquid level controller according to claim 1, characterized in that: The three electrodes of the liquid level sensor (101) are three plastic-insulated copper wires, wherein the first plastic-insulated copper wire is exposed as a copper wire at the bottom of the water tank (107) as a lower electrode (13), the second plastic-insulated copper wire is exposed as a copper wire at a low liquid level of the water tank (107) as a middle electrode (12), and the third plastic-insulated copper wire is exposed as a copper wire at a high liquid level of the water tank (107) as an upper electrode (11).

3. A universal liquid level controller according to claim 1 or 2, characterized in that: The output drive of the actuator (105) is connected to a relay (109), and the normally open contact (110) of the relay (109) is connected in series to the power supply circuit of the water supply solenoid valve (108).

Images