Gas heating furnace fan speed detection circuit and gas heating furnace

Abstract

The present invention discloses a fan speed detection circuit for a gas heating furnace and the gas heating furnace. The detection circuit includes a fan speed input circuit for obtaining a fan speed signal; a hysteresis comparator circuit for shielding interference signals and connected to the fan speed input circuit; and a fan speed feedback circuit for outputting a fan speed feedback signal and connected to the hysteresis comparator circuit. By providing a hysteresis comparator circuit, the present invention can shield the fan speed detection process from interference from the external environment, accurately detect the fan speed, achieve precise control of the fan, and improve the operating efficiency of the gas heating furnace.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas heating furnaces, and in particular relates to a fan speed detection circuit of a gas heating furnace and the gas heating furnace. Background Art

[0002] Gas heating furnaces typically use gas as fuel, transferring heat energy through combustion to cold water flowing through a heat exchanger, achieving both heating and hot water production. A typical gas heating furnace consists of a combustion chamber, ignition device, control valve, fan, smoke pipe, and control panel. The fan is located at the top of the furnace, while the control panel is located at the bottom.

[0003] When the gas heating furnace is working, the control valve is opened, and the gas enters the combustion chamber through the control valve and starts to burn under the action of the ignition device. The fan speed is determined according to the amount of gas, and air is introduced into the combustion chamber through the fan to ensure that the amount of gas corresponds to the air volume, so that the gas heating furnace can work normally.

[0004] Gas heating furnaces require varying amounts of gas and air under different load conditions. The performance of a gas heating furnace is determined by both the gas and air. The stability of the gas is determined by the control valve, while the amount of air is ensured by the fan. Air volume can fluctuate due to variations in altitude, installation environment, and the characteristics of the smoke pipe itself. Air volume is determined by the fan speed.

[0005] To improve the efficiency of gas heating furnaces, it is necessary to test the fan speed and accurately control the fan based on the test results. During the test process, interference from the high temperature of the combustion chamber, the high-voltage ignition device, and the mains electricity can lead to inaccurate test results and affect the precise control of the fan.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a fan speed detection circuit and a gas heating furnace for a gas heating furnace, which can shield the interference of the environment on the fan speed detection and accurately detect the fan speed.

[0008] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0009] A fan speed detection circuit for a gas heating furnace, comprising:

[0010] Fan speed input circuit, used to obtain fan speed signal;

[0011] The hysteresis comparator circuit is used to shield interference signals and is connected to the fan speed input circuit;

[0012] The fan speed feedback circuit is used to output a feedback signal of the fan speed and is connected to the hysteresis comparison circuit.

[0013] Preferably, the hysteresis comparison circuit includes a voltage comparator IC1, the inverting input terminal IN1- of the voltage comparator IC1 is connected to the fan speed input circuit, the non-inverting input terminal IN1+ of the voltage comparator IC1 is connected to the first end of the resistor R1 and the first end of the resistor R2, the second end of the resistor R2 is connected to the first power supply, the second end of the resistor R1 is grounded, and the output terminal OUT1 of the voltage comparator IC1 is connected to the fan speed feedback circuit.

[0014] Preferably, the non-inverting input terminal IN1+ of the voltage comparator IC1 is connected to the output terminal OUT1 of the voltage comparator IC1 via the resistor R3, the non-inverting input terminal IN1+ of the voltage comparator IC1 is grounded via the capacitor C1, and the output terminal OUTA of the voltage comparator IC1 is connected to the first power supply via the resistor R4.

[0015] Preferably, the fan speed feedback circuit includes a resistor R5 and a capacitor C3, the output end OUT1 of the voltage comparator IC1 is connected to the first end of the resistor R5, the second end of the resistor R5 is connected to the fan speed feedback port P1, and the second end of the resistor R5 is grounded via the capacitor C3.

[0016] Preferably, the fan speed input circuit includes a transistor N1, the base of the transistor N1 is connected to the fan speed signal input port P3, the collector of the transistor N1 is connected to pin 3 of the electrical connector CN1 via a resistor R7, the emitter of the transistor N1 is grounded, and the pin 2 of the electrical connector CN1 is connected to the reverse input terminal IN1- of the voltage comparator IC1 via a resistor R6.

[0017] Preferably, the collector of the transistor is connected to the first power supply via the resistor R8, the pin 5 of the electrical connector CN1 is connected to the second power supply, and the pin 4 of the electrical connector is grounded.

[0018] Preferably, it includes a fan power feedback circuit, which includes a transistor N2, the base of the transistor N2 is connected to pin 1 of the electrical connector CN1 via a resistor R9, the collector of the transistor N2 is connected to the fan power feedback port P2, and the emitter of the transistor N2 is grounded.

[0019] Preferably, the base of the transistor N2 is connected to the first end of the resistor R10 and the first end of the capacitor C4, and the second end of the resistor R10 and the second end of the capacitor C4 are grounded.

[0020] Preferably, the collector of the transistor N2 is connected to the first end of the resistor R12 and the first end of the resistor R11, the second end of the resistor R12 is connected to the fan power feedback port P2, the second end of the resistor R12 is grounded via the capacitor C5, and the collector of the transistor N2 is connected to the first power supply via the resistor R11.

[0021] Another object of the present invention is to provide a gas heating furnace, comprising a fan and a control circuit board, wherein the fan is connected to the control circuit board, and the control circuit board is provided with a fan speed detection circuit of the gas heating furnace as described above.

[0022] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0023] The present invention provides a hysteresis comparison circuit that shields interference signals with smaller amplitudes and is suitable for protecting important signals in a working environment with complex interference signals. The interference of the external environment on the fan speed detection process can be shielded during the detection of the fan speed, and the fan speed can be accurately detected to achieve precise control of the fan, thereby ensuring the normal operation of the gas heating furnace and improving the working efficiency of the gas heating furnace. The present invention protects the fan speed signal and uses a hysteresis comparison circuit to shield the interference signal, making the signal transmitted to the single-chip microcomputer cleaner and more effective, allowing the single-chip microcomputer to accurately detect the fan speed and ensure that the gas heating furnace can operate normally in an environment with strong interference.

[0024] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are part of the present invention and 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, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0026] Figure 1 The present invention is a schematic diagram of a fan speed detection circuit for a gas heating furnace.

[0027] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0031] like Figure 1 As shown, an embodiment of the present invention introduces a fan speed detection circuit for a gas heating furnace, including a fan speed input circuit for obtaining a fan speed signal; a hysteresis comparison circuit for shielding interference signals, connected to the fan speed input circuit; and a fan speed feedback circuit for outputting a feedback signal of the fan speed, connected to the hysteresis comparison circuit.

[0032] To ensure proper operation of a gas heating furnace, the air intake must be adjusted according to the gas level. This is typically done via a proportional valve installed within the furnace, and the air intake is adjusted by adjusting the fan speed. However, when detecting fan speed, the high internal temperature of the furnace during operation interferes with signal transmission, leading to inaccurate fan speed detection and affecting the furnace's proper operation.

[0033] The present invention provides a hysteresis comparison circuit that shields interference signals with smaller amplitudes and is suitable for protecting important signals in a working environment with complex interference signals. The interference of the external environment on the fan speed detection process can be shielded during the detection of the fan speed, and the fan speed can be accurately detected to achieve precise control of the fan, thereby ensuring the normal operation of the gas heating furnace and improving the working efficiency of the gas heating furnace. The present invention protects the fan speed signal and uses a hysteresis comparison circuit to shield the interference signal, making the signal transmitted to the single-chip microcomputer cleaner and more effective, allowing the single-chip microcomputer to accurately detect the fan speed and ensure that the gas heating furnace can operate normally in an environment with strong interference.

[0034] like Figure 1 As shown, in the embodiment of the present invention, the hysteresis comparison circuit includes a voltage comparator IC1, the inverting input terminal IN1- of the voltage comparator IC1 is connected to the fan speed input circuit, the non-inverting input terminal IN1+ of the voltage comparator IC1 is connected to the first end of the resistor R1 and the first end of the resistor R2, the second end of the resistor R2 is connected to the first power supply, the second end of the resistor R1 is grounded, and the output terminal OUT1 of the voltage comparator IC1 is connected to the fan speed feedback circuit.

[0035] The non-inverting input terminal IN1+ of the voltage comparator IC1 is connected to the output terminal OUT1 of the voltage comparator IC1 through the resistor R3, the non-inverting input terminal IN1+ of the voltage comparator IC1 is grounded through the capacitor C1, and the output terminal OUTA of the voltage comparator IC1 is connected to the first power supply through the resistor R4.

[0036] The voltage comparator IC1 in this embodiment is a dual voltage comparator LM393-SOP8, the voltage of the first power supply is 5V, the fan speed signal is input to the reverse input terminal IN1- of the voltage comparator IC1, the resistance value of the resistor R3 is 33KΩ, the resistance value of the resistor R2 is 56KΩ, and the resistance value of the resistor R1 is 56KΩ.

[0037] The voltage at the non-inverting input terminal IN1+ of the voltage comparator IC1 is Ut. When the voltage comparator IC1 outputs a high level, the voltage Uo at the output terminal OUT1 of the voltage comparator IC1 is usually 3.8V. According to the formula (Uo-Ut) / R3+(5-Ut) / R2=Ut / R1, it can be calculated that the voltage Ut at the non-inverting input terminal IN1+ of the voltage comparator IC1 when the voltage comparator IC1 outputs a high level is 3V.

[0038] When the voltage comparator IC1 outputs a low level, the voltage U0 at the output terminal OUT1 of the voltage comparator IC1 is usually 0 V. At this time, Ut / R3+Ut / R1=(5-Ut) / R2. It can be calculated that the voltage Ut at the non-inverting input terminal IN1+ of the voltage comparator IC1 is 1.3 V when the voltage comparator IC1 outputs a low level.

[0039] When the voltage at the non-inverting input terminal of the voltage comparator IC1 is higher than the voltage at the inverting input terminal of the voltage comparator IC1, the voltage comparator IC1 outputs a high level; if the voltage at the non-inverting input terminal of the voltage comparator IC1 is lower than the voltage at the inverting input terminal of the voltage comparator IC1, the voltage comparator IC1 outputs a low level.

[0040] In this embodiment, the fan speed signal is input to the inverting input terminal of the voltage comparator IC1. Only when the high level of the voltage value of the fan speed signal is lower than 1.3V, or the low level rises to above 3V, the high and low level signals will be reversed at the output terminal OUT1 of the voltage comparator IC1. The output signal of the voltage comparator IC1 is transmitted to the single-chip microcomputer through the fan speed feedback circuit. The single-chip microcomputer outputs the correct control signal according to the received signal to control the fan, thereby ensuring the normal operation of the gas heating furnace.

[0041] like Figure 1 As shown, in the embodiment of the present invention, the power supply terminal VCC of the voltage comparator IC1 is connected to the first power supply and the first end of the capacitor C2, and the second end of the capacitor C2 is grounded.

[0042] The present invention provides a capacitor C2 at the power supply terminal VCC of the voltage comparator IC1, thereby filtering interference in the power supply, stabilizing the voltage, improving the working stability of the voltage comparator IC1, ensuring the normal operation of the voltage comparator IC1, shielding interference signals, improving the accuracy of the fan speed detection results, and ensuring the normal operation of the gas heating furnace.

[0043] like Figure 1 As shown, in this embodiment of the present invention, the fan speed feedback circuit includes a resistor R5 and a capacitor C3. The output terminal OUT1 of the voltage comparator IC1 is connected to the first end of the resistor R5. The second end of the resistor R5 is connected to the fan speed feedback port P1. The second end of the resistor R5 is grounded via the capacitor C3. The fan speed feedback port P1 is connected to the detection pin of the microcontroller.

[0044] The fan speed feedback circuit is a filter circuit used to filter out the noise in the output signal of the voltage comparator IC1. The output signal of the voltage comparator IC1 passes through the filter circuit and is transmitted to the microcontroller through the fan speed feedback port. The microcontroller outputs the correct control signal based on the received signal to control the fan and ensure the normal operation of the gas heating furnace.

[0045] like Figure 1 As shown, the fan speed input circuit includes a transistor N1, the base of the transistor N1 is connected to the fan speed signal input port P3, the collector of the transistor N1 is connected to the pin 3 of the electrical connector CN1 via the resistor R7, the emitter of the transistor N1 is grounded, and the pin 2 of the electrical connector CN1 is connected to the inverting input terminal IN1- of the voltage comparator IC1 via the resistor R6.

[0046] The collector of the transistor is connected to the first power supply via the resistor R8 , the pin 5 of the electrical connector CN1 is connected to the second power supply, and the pin 4 of the electrical connector is grounded.

[0047] The fan speed signal is input to transistor N1, which amplifies the fan speed signal to prevent distortion. A pull-up resistor R3 is connected to the collector of transistor N2. R3 is connected to a +5V power supply, providing a DC bias for the collector of transistor N2, allowing transistor N1 to operate in an amplified state.

[0048] like Figure 1 As shown, the fan power feedback circuit includes a transistor N2, the base of the transistor N2 is connected to the pin 1 of the electrical connector CN1 via the resistor R9, the collector of the transistor N2 is connected to the fan power feedback port P2, and the emitter of the transistor N2 is grounded.

[0049] The base of the transistor N2 is connected to a first end of the resistor R10 and a first end of the capacitor C4 , and a second end of the resistor R10 and a second end of the capacitor C4 are grounded.

[0050] The collector of transistor N2 is connected to the first end of resistor R12 and the first end of resistor R11, the second end of resistor R12 is connected to the wind turbine power feedback port P2, the second end of resistor R12 is grounded via capacitor C5, and the collector of transistor N2 is connected to the first power supply via resistor R11.

[0051] The fan power feedback circuit is used to detect the fan power based on the fan speed signal, and to determine the fan's operating status based on the fan power, thereby determining whether the fan is operating normally. By detecting the fan speed and fan power simultaneously, the present invention obtains the fan's operating status in real time, allowing the gas heating furnace to operate normally in an environment with strong interference, ensuring the normal operation of the gas heating furnace and improving its operating efficiency.

[0052] An embodiment of the present invention introduces a gas heating furnace, including a fan and a control circuit board. The fan is connected to the control circuit board, and the control circuit board is provided with a fan speed detection circuit of a gas heating furnace as described in any of the above embodiments.

[0053] To ensure proper operation of a gas heating furnace, the air intake must be adjusted according to the gas level. This is typically done via a proportional valve installed within the furnace, and the air intake is adjusted by adjusting the fan speed. However, when detecting fan speed, the high internal temperature of the furnace during operation interferes with signal transmission, leading to inaccurate fan speed detection and affecting the furnace's proper operation.

[0054] During the operation of the heating furnace, the fan speed signal passes through the fan speed input circuit and is transmitted to the hysteresis comparator circuit. The hysteresis comparator circuit is used to shield the interference signal, accurately detect the fan speed, and achieve precise control of the fan, thereby ensuring the normal operation of the gas heating furnace and improving the working efficiency of the gas heating furnace.

[0055] The present invention provides a hysteresis comparison circuit that shields interference signals with smaller amplitudes and is suitable for protecting important signals in a working environment with complex interference signals. The interference of the external environment on the fan speed detection process can be shielded during the detection of the fan speed, and the fan speed can be accurately detected to achieve precise control of the fan, thereby ensuring the normal operation of the gas heating furnace and improving the working efficiency of the gas heating furnace. The present invention protects the fan speed signal and uses a hysteresis comparison circuit to shield the interference signal, making the signal transmitted to the single-chip microcomputer cleaner and more effective, allowing the single-chip microcomputer to accurately detect the fan speed and ensure that the gas heating furnace can operate normally in an environment with strong interference.

[0056] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0057] All features disclosed in this specification (including accompanying claims, abstracts and drawings) and all processes or units of any method or apparatus disclosed herein may be combined in any combination, except where at least some of such features and / or processes or units are mutually exclusive. Unless expressly stated otherwise, each feature disclosed in this specification (including accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0058] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features and not other features included in other embodiments, the combination of features from different embodiments is intended to be within the scope of the invention and to form different embodiments.

[0059] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments of equivalent changes using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. The implementation schemes in the above-mentioned embodiments can also be further combined or replaced. However, any simple modifications, equivalent changes and modifications made to the above-mentioned embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A fan speed detection circuit for a gas heating furnace, characterized in that: include: Fan speed input circuit, used to obtain fan speed signal; The hysteresis comparator circuit is used to shield interference signals and is connected to the fan speed input circuit; The fan speed feedback circuit is used to output a feedback signal of the fan speed and is connected to the hysteresis comparator circuit; Electrical connector CN1, used to integrate the fan speed input signal and power feedback signal, with pin 2 connected to the hysteresis comparator circuit, pin 3 connected to the fan speed input circuit, pin 1 connected to the fan power feedback circuit, pin 5 connected to the second power supply, and pin 4 connected to ground; The wind turbine power feedback circuit includes a transistor N2, the base of the transistor N2 is connected to pin 1 of the electrical connector CN1 via a resistor R9, the collector of the transistor N2 is connected to the wind turbine power feedback port P2, and the emitter of the transistor N2 is grounded; The fan speed input circuit includes a transistor N1 , the base of which is connected to the fan speed signal input port P3 , the collector of which is connected to the pin 3 of the electrical connector CN1 via a resistor R7 , and the emitter of which is grounded.

2. A fan speed detection circuit for a gas heating furnace according to claim 1, characterized in that: The hysteresis comparison circuit includes a voltage comparator IC1, an inverting input terminal IN1- of the voltage comparator IC1 is connected to the fan speed input circuit, a non-inverting input terminal IN1+ of the voltage comparator IC1 is connected to the first end of the resistor R1 and the first end of the resistor R2, a second end of the resistor R2 is connected to the first power supply, a second end of the resistor R1 is grounded, and an output terminal OUT1 of the voltage comparator IC1 is connected to the fan speed feedback circuit.

3. The fan speed detection circuit of a gas heating furnace according to claim 2, characterized in that: The non-inverting input terminal IN1+ of the voltage comparator IC1 is connected to the output terminal OUT1 of the voltage comparator IC1 through the resistor R3, the non-inverting input terminal IN1+ of the voltage comparator IC1 is grounded through the capacitor C1, and the output terminal OUTA of the voltage comparator IC1 is connected to the first power supply through the resistor R4.

4. The fan speed detection circuit of a gas heating furnace according to claim 3, characterized in that: The fan speed feedback circuit includes a resistor R5 and a capacitor C3. The output terminal OUT1 of the voltage comparator IC1 is connected to the first end of the resistor R5. The second end of the resistor R5 is connected to the fan speed feedback port P1. The second end of the resistor R5 is grounded via the capacitor C3.

5. A fan speed detection circuit for a gas heating furnace according to any one of claims 2 to 4, characterized in that: Pin 2 of the electrical connector CN1 is connected to the inverting input terminal IN1- of the voltage comparator IC1 via the resistor R6.

6. A fan speed detection circuit for a gas heating furnace according to claim 5, characterized in that: The collector of the transistor is connected to the first power supply via the resistor R8 , the pin 5 of the electrical connector CN1 is connected to the second power supply, and the pin 4 of the electrical connector is grounded.

7. A fan speed detection circuit for a gas heating furnace according to claim 6, characterized in that: The base of the transistor N2 is connected to a first end of the resistor R10 and a first end of the capacitor C4 , and a second end of the resistor R10 and a second end of the capacitor C4 are grounded.

8. The fan speed detection circuit of a gas heating furnace according to claim 7, characterized in that: The collector of transistor N2 is connected to the first end of resistor R12 and the first end of resistor R11, the second end of resistor R12 is connected to the wind turbine power feedback port P2, the second end of resistor R12 is grounded via capacitor C5, and the collector of transistor N2 is connected to the first power supply via resistor R11.

9. A gas heating furnace, characterized in that: The invention comprises a fan and a control circuit board, wherein the fan is connected to the control circuit board, and the control circuit board is provided with a fan speed detection circuit of a gas heating furnace as described in any one of claims 1 to 8.

Images