Purified water alternating current electric heating system

Abstract

The utility model discloses an alternating current heating system for purified water. The alternating current heating system comprises a heating control circuit, a microcontroller, a direct current voltage stabilizing circuit, a display unit, a temperature acquisition unit and a heating unit, the input end of the heating control circuit is connected with the PWM signal output end of the microcontroller, and the output end of the heating control circuit is connected with the heating unit; a communication interface of the microcontroller is connected with the display unit, and a data interface of the microcontroller is connected with the temperature acquisition unit; the power output end of the direct-current voltage stabilizing circuit is connected with the power input end of the microcontroller, and the direct-current voltage stabilizing circuit is used for providing set direct-current power for the microcontroller. Whether the heating unit is abnormal or not is judged by detecting the temperature value, the heating system is turned off in time when abnormity occurs, and expansion of faults of the heating system is effectively prevented; the microcontroller adjusts the duty ratio of the output PWM signal in real time according to the temperature detection value to control the heating power of the heating unit, the target temperature control precision of the water temperature is high, the heating speed is high, and meanwhile power consumption is reduced.

Description

Technical Field

[0001] The utility model relates to purified water used in medical devices, in particular to an alternating current heating system for the purified water. Background Art

[0002] In the field of medical devices, the purified water needs to be quickly heated to a target temperature to quickly clean the sample needle and the air bubbles in its pipeline. Since the direct current heating of purified water has disadvantages such as low efficiency and long heating time, the alternating current heating method is usually adopted for the purified water used in medical devices; to improve the heating speed of purified water, the method of increasing the heating current is mostly used to achieve it; however, increasing the heating current makes it difficult to control the target temperature of the water temperature, and at the same time, the overcurrent protection mainly uses fuses and circuit breakers, resulting in a long recovery heating time after the overcurrent protection occurs, which also reduces the heating efficiency of the purified water. Summary of the Invention

[0003] The utility model provides an alternating current heating system for purified water, which can quickly heat the purified water to the target temperature while ensuring the safe and reliable operation of the alternating current heating system.

[0004] To achieve the above object, the utility model adopts the following technical solutions:

[0005] The alternating current heating system for purified water of the utility model includes a heating control circuit, a microcontroller, a DC voltage stabilizing circuit, a display unit, a temperature acquisition unit, and a heating unit.

[0006] The control signal input end of the heating control circuit is connected to the PWM signal output end of the microcontroller, and the control signal output end of the heating control circuit is connected to the heating unit, which is used to control the heating unit to connect / disconnect the AC power supply and control the temperature of the heating unit; the communication interface of the microcontroller is connected to the display unit, and the data interface of the microcontroller is connected to the temperature acquisition unit, which is used to receive the temperature data sent by the temperature acquisition unit; the temperature acquisition unit is used to collect the temperature value of the heating unit in real time and send the temperature value to the microcontroller; the power output end of the DC voltage stabilizing circuit is connected to the power input end of the microcontroller, which is used to provide a set DC power supply to the microcontroller.

[0007] Optionally, the heating unit includes a heat exchanger, which is composed of a housing provided with an inlet and an outlet, and an electric heating rod and a water level gauge arranged in the housing; the detection signal output end of the water level gauge is connected to the data signal input end of the microcontroller; the power input end of the electric heating rod is connected to a two-phase AC power supply through the heating control circuit; the water level gauge is used to detect the water level of the purified water in the housing of the heat exchanger and output the water level detection data to the microcontroller;

[0008] The temperature acquisition unit includes a temperature sensor; the temperature sensor is arranged inside the heat exchanger housing, and the signal output end of the temperature sensor is connected to the data signal input end of the microcontroller;

[0009] The heating control circuit includes an opto-coupler isolator U1 and a bidirectional thyristor Q1; the input end of the opto-coupler isolator U1 is connected to the PWM signal output end of the microcontroller, and the output end of the opto-coupler isolator U1 is connected to the first anode t1, the second anode t2 and the gate g of the bidirectional thyristor Q1 through a voltage dividing circuit composed of resistors R3, R4 and R5.

[0010] Optionally, the opto-coupler isolator U1 is a zero-crossing bidirectional thyristor opto-coupler isolator, and a heating indication circuit composed of a series circuit of R1 and D1 is connected to the input end of the zero-crossing bidirectional thyristor opto-coupler isolator.

[0011] Compared with the prior art, the beneficial effects of the present utility model are:

[0012] 1. By detecting the temperature value sent by the temperature detection unit in real time, it is judged whether the heating unit is abnormal, and when an abnormal situation occurs, the heating system is turned off in time, effectively preventing the expansion of the heating system failure;

[0013] 2. According to the temperature detection value sent by the temperature acquisition unit to the microcontroller in real time, the duty cycle of the output PWM signal is adjusted in real time, and the heating power of the heating unit is controlled through the heating control circuit, with high control accuracy of the target water temperature, fast heating speed, and reduced power consumption at the same time;

[0014] 3. The status of the heating system is displayed in real time through the display unit, and when an abnormal situation occurs in the heating system, personnel are notified in time for handling. Description of the Drawings

[0015] Figure 1 is the circuit principle block diagram of the special heating system described in the present utility model.

[0016] Figure 2 is the schematic diagram of the principle of the heating control circuit described in the present utility model.

[0017] Figure 3 is the structural schematic diagram of the heat exchanger described in the present utility model.

[0018] Figure 4 is the heating flow chart of the heating unit described in the present utility model. Detailed Embodiments

[0019] In order to make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0020] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "inside" and "outside" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0021] As Figures 1-3 shown, the purified water alternating current heating system described in the present utility model includes a heating control circuit 1, a microcontroller, a DC voltage stabilizing circuit, a display unit, a temperature acquisition unit, and a heating unit 2.

[0022] The control signal input end of the heating control circuit 1 is connected to the PWM signal output end of the microcontroller (single-chip microcomputer, model GD32F103RET6). The control signal output end of the heating control circuit 1 is connected to the heating unit 2. The heating control circuit 1 is used to control the heating unit 2 to connect / disconnect the 220V AC power supply and control the temperature of the heating unit 2. The communication interface of the microcontroller is connected to the display unit (display) for displaying the working state of the heating system. The data interface of the microcontroller is connected to the temperature acquisition unit for receiving the temperature data sent by the temperature acquisition unit. The temperature acquisition unit is used to collect the temperature value of the heating unit 2 in real time and send the collected temperature value to the microcontroller. The power output end of the DC voltage stabilizing circuit is connected to the power input end of the microcontroller for providing a set DC power supply to the microcontroller.

[0023] Preferably or exemplarily, as Figure 3 shown, the heating unit 2 includes a heat exchanger, which is composed of a housing 2.3 provided with inlets and outlets 2.1 and 2.2, and an electric heating rod 2.4 and a water level gauge 2.5 arranged inside the housing 2.3. The detection signal output end of the water level gauge 2.5 is connected to the data signal input end of the microcontroller, and the liquid level data of the purified water in the housing 2.3 is sent to the microprocessor in real time. The power input end of the electric heating rod 2.4 is connected to the 220V AC power supply through the heating control circuit 1.

[0024] As an embodiment, the temperature acquisition unit includes a temperature sensor 2.6. The temperature sensor 2.6 is arranged in the inner cavity of the heat exchanger housing 2.3, and the detection signal output end of the temperature sensor 2.6 is connected to the data signal input end of the microcontroller.

[0025] Preferably or exemplarily, as Figure 2As shown, the heating control circuit 1 includes a zero-crossing bidirectional thyristor optocoupler isolator U1 (model MOC3063) and a bidirectional thyristor Q1; the signal input terminal (pin 2) of the zero-crossing bidirectional thyristor optocoupler isolator U1 is connected to the microcontroller PWM signal output terminal PWM_0 via a filter circuit composed of a resistor R1 and a capacitor C1, which effectively prevents signal interference and signal oscillation; the power input terminal (pin 1) of the zero-crossing bidirectional thyristor optocoupler isolator U1 is connected to the microcontroller PWM signal output terminal PWM_0 via a current limiting resistor R2 and a light emitting diode D1, which is used to give a heating indication when the microcontroller outputs a PWM signal, and is turned off when the microcontroller has no PWM signal output.

[0026] The first signal output terminal T1 (pin 4) of the zero-crossing bidirectional thyristor optocoupler isolator U1 is connected to the gate g of the bidirectional thyristor Q1, and is connected to the first anode t1 of the bidirectional thyristor Q1 via the resistor R5; the second signal output terminal T2 (pin 6) of the zero-crossing bidirectional thyristor optocoupler isolator U1 is connected to the second anode t2 of the bidirectional thyristor Q1 via the series resistors R3 and R4; the second anode t2 of the bidirectional thyristor Q1 is connected to the live wire terminal of the 220V AC power supply, and the first anode t1 of the bidirectional thyristor Q1 is connected to the neutral wire terminal of the 220V AC power supply via the electric heating rod 2.4 and the fuse F1.

[0027] like Figure 4 As shown, the working process of the heating unit of the utility model is as follows:

[0028] Step 1: Set the target temperature value T of the heating unit through the microcontroller M 、Target temperature upper limit T s 、Target temperature lower limit T x ;

[0029] Step 2: When the heating unit is not heated, the display unit displays the liquid level information; the microcontroller detects whether the temperature acquisition unit is abnormal. If the temperature acquisition unit is abnormal, the abnormal cause is reported and the heating is stopped through the display unit; the specific steps are as follows:

[0030] Step 2.1, when the temperature sensor 2.6 selects a positive temperature coefficient such as a PTC type temperature sensor, the microcontroller compares the temperature measuring resistance value of the temperature value sent by the temperature sensor 2.6 with the resistance value in the resistance graduation table of the temperature sensor 2.6:

[0031] If the temperature sensor 2.6 sends a temperature value with a temperature measuring resistance value greater than the maximum resistance value in the resistance scale, the microcontroller determines that the temperature sensor 2.6 is open circuited; if the temperature sensor 2.6 sends a temperature value with a temperature measuring resistance value less than the resistance value corresponding to 0°C in the resistance scale, and the ambient temperature is greater than 0°C, the microcontroller determines that the temperature sensor 2.6 is short circuited; an ambient temperature greater than 0°C indicates that the temperature of the heated purified water is higher than the freezing point;

[0032] Step 2.2, when the temperature sensor selects a negative temperature coefficient such as an NTC type temperature sensor, the microcontroller compares the measured temperature resistance value of the temperature value sent by the temperature sensor 2.6 with the resistance value in the resistance graduation table of the temperature sensor 2.6: If the measured temperature resistance value of the temperature value sent by the temperature sensor 2.6 is greater than the maximum resistance value in the resistance graduation table and the ambient temperature is greater than 0°C, the microcontroller determines that the temperature sensor 2.6 is open; if the measured temperature resistance value of the temperature value sent by the temperature sensor 2.6 is less than the minimum resistance value in the resistance graduation table, the microcontroller determines that the temperature sensor 2.6 is short-circuited; the ambient temperature being greater than 0°C means that the temperature of the purified water being heated is higher than the freezing point;

[0033] Step 3, when the heating unit is heating, the temperature sensor 2.6 sends the temperature detection value T0 to the microcontroller in real time; when T0 < T x , the microcontroller outputs a PWM signal with a duty cycle of 100% to the heating control circuit 1, and the heating control circuit controls the heating unit to heat at full power;

[0034] Step 4, when T0 ≥ T s , the microcontroller outputs a PWM signal with a duty cycle of 0 to the heating control circuit 1, and the heating control circuit 1 controls the heating unit to stop heating;

[0035] Step 5, when T x < T0 < T s , the microcontroller adjusts the duty cycle of the output PWM signal, that is: when T0 < T M , increase the duty cycle of the output PWM signal; when T M < T0, decrease the duty cycle of the output PWM signal; when T0 = T M , keep the duty cycle of the currently output PWM signal.

[0036] During the heating process of the heating unit, the microcontroller detects whether the temperature acquisition unit is abnormal in real time according to Step 2.1 or Step 2.2. If an abnormality occurs, the microcontroller outputs a PWM signal with a duty cycle of 0 to the heating control circuit 1, and the heating unit stops heating and reports the cause of the abnormality to avoid further fault losses.

Claims

1. A purified water AC heating system, characterized in that: It includes a heating control circuit, a microcontroller, a DC voltage stabilizing circuit, a display unit, a temperature acquisition unit, and a heating unit; The control signal input end of the heating control circuit is connected to the PWM signal output end of the microcontroller, and the control signal output end of the heating control circuit is connected to the heating unit, which is used to control the heating unit to connect / disconnect the AC power supply and control the temperature of the heating unit; the microcontroller communication interface is connected to the display unit, and the microcontroller data interface is connected to the temperature acquisition unit, which is used to receive the temperature data sent by the temperature acquisition unit; the temperature acquisition unit is used to collect the temperature value of the heating unit in real time and send the temperature value to the microcontroller; the DC voltage stabilizing circuit power supply output end is connected to the microcontroller power supply input end, which is used to provide a set DC power supply to the microcontroller.

2. The purified water AC heating system according to claim 1, characterized in that: The heating unit comprises a heat exchanger, which is composed of a shell provided with a water inlet and a water outlet, and an electric heating rod and a water level meter arranged in the shell; the detection signal output end of the water level meter is connected to the data signal input end of the microcontroller; the power input end of the electric heating rod is connected to a two-phase AC power supply through a heating control circuit; The temperature acquisition unit includes a temperature sensor; the temperature sensor is arranged inside the heat exchanger housing, and the temperature sensor detection signal output end is connected to the microcontroller data signal input end; The heating control circuit includes an optical coupling isolator U1 and a bidirectional thyristor Q1; the input end of the optical coupling isolator U1 is connected to the PWM signal output end of the microcontroller, and the output end of the optical coupling isolator U1 is connected to the first anode t1, the second anode t2 and the gate g of the bidirectional thyristor Q1 through a resistor voltage divider circuit.

3. The purified water AC heating system according to claim 2, characterized in that: The optical coupling isolator U1 is a zero-crossing bidirectional thyristor optical coupling isolator, and a heating indication circuit is connected to an input end of the zero-crossing bidirectional thyristor optical coupling isolator.

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