Electrostatic spray gun explosion protection device

Abstract

The application discloses an electrostatic spray gun explosion-proof protection device, which comprises a control module, a fuse, an input judging module, an output judging module, a trigger module and a delay module. The input judging module is connected with the power supply end of the control module. When the input voltage is greater than a first threshold value, the input judging module outputs a first trigger signal. The output judging module is connected with the output end of the control module. When the driving voltage is greater than a second threshold value, the output judging module outputs a second trigger signal. The trigger module is connected with the input judging module and the output judging module. When the trigger module receives any one of the first trigger signal and the second trigger signal, a fuse signal is formed to make the fuse fuse. The delay module is connected with the power supply end of the control module and the trigger module. When the power supply end of the control module is powered or the power supply end of the control module is powered off, the delay module controls the trigger module to not form the fuse signal. The design is reliable and stable in operation, and the electrostatic spray gun is safe in use.

Description

Technical Field

[0001] This invention relates to the field of electrostatic spraying electronic circuit technology, and in particular to an explosion-proof protection device for an electrostatic spray gun. Background Technology

[0002] In the coating process production line, electrostatic spray guns use a low-pressure high-atomization device and an electrostatic generator to generate an electrostatic electric field force to efficiently and quickly spray paint onto the surface of the object to be coated. The electrostatic spray gun power supply needs to generate up to 100KV / 100uA of static electricity for the spray gun. The charge of the electrostatic spray gun must comply with the specified standards. If the electrostatic spray gun power supply goes out of control, resulting in overvoltage or overcurrent, it can easily cause dust explosions and fires.

[0003] Existing explosion-proof protection devices for electrostatic spray guns all involve installing fuses on the power supply lines of the input power supply and control module. When the input voltage of the control module or the driving voltage supplied to the electrostatic spray gun after being modulated by the control module is over-voltage, the protection device will melt the fuse to protect the safe use of the electrostatic spray gun.

[0004] However, problems exist in actual use. During the power-on or power-off process of the protection device, the timing of the power supply signal of the input power supply, the power supply of the protection device, and the reference voltage source is inconsistent, which can easily trigger the malfunction of the protection device. Even if no overvoltage occurs, the fuse will blow, which means that the protection device needs to be reset and maintained frequently, and may even damage the protection device. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes an explosion-proof protection device for electrostatic spray guns, which operates reliably and stably, ensuring safe use of the electrostatic spray gun.

[0006] An explosion-proof protection device for an electrostatic spray gun according to a first aspect of the present invention includes: a control module for connection to the electrostatic spray gun, the control module being capable of outputting a driving voltage to control the operation of the electrostatic spray gun; a fuse for connection to an input power supply and a power supply terminal of the control module, the input power supply providing an input voltage to the control module through the fuse; an input judgment module connected to the power supply terminal of the control module to obtain the input voltage, the input judgment module outputting a first trigger signal when the input voltage is greater than a first threshold; and an output judgment module connected to the output terminal of the control module to obtain a driving voltage, the output judgment module outputting a second trigger signal when the driving voltage is greater than a second threshold. The trigger module is connected to the input judgment module and the output judgment module respectively. When the trigger module receives either the first trigger signal or the second trigger signal, the trigger module generates a fuse signal. The trigger module is connected to the fuse element so that the fuse element melts through the fuse signal. The delay module is connected to the power supply terminal of the control module and the trigger module respectively. When the power supply terminal of the control module is powered on, the delay module controls the trigger module to remain in a locked state during the first delay period. When the power supply terminal of the control module is de-powered, the delay module controls the trigger module to remain in a locked state during the second delay period. In the locked state, the trigger module does not generate a fuse signal.

[0007] An explosion-proof protection device for an electrostatic spray gun according to an embodiment of the present invention has at least the following beneficial effects:

[0008] This invention relates to an explosion-proof protection device for electrostatic spray guns. During operation, the input judgment module acquires the input voltage. When the input voltage exceeds a first threshold, it outputs a first trigger signal. Similarly, the output judgment module acquires the driving voltage. When the driving voltage exceeds a second threshold, it outputs a second trigger signal. Either the first or second trigger signal can cause the trigger module to generate a fuse signal, which melts the fuse element, thus ensuring the safe use of the electrostatic spray gun. At the moment the control module is powered on or off, the delay module maintains the trigger module in a locked state during the first delay period after power is on and the second delay period after power is off. In the locked state, the trigger module does not generate a fuse signal, thus preventing the fuse element from melting. Furthermore, in the initial stage of power on, the control module has not yet completed the modulation of the driving voltage, so the driving voltage will not be too high and cause the electrostatic spray gun to go out of control. Similarly, it will not cause the electrostatic spray gun to go out of control when power is off. Therefore, this design is reliable and stable in operation, ensuring the safe use of the electrostatic spray gun.

[0009] According to some embodiments of the present invention, the triggering module includes a first switching unit, a second switching unit, and a triggering unit. The first switching unit and the second switching unit are connected in series to form at least a partial triggering circuit. The controlled terminal of the first switching unit is connected to the input judgment module and the output judgment module, respectively. When the controlled terminal of the first switching unit receives either a first trigger signal or a second trigger signal, the first switching unit is triggered to switch on or off. The controlled terminal of the second switching unit is connected to the delay module, and the delay module can trigger the second switching unit to switch on or off. One end of the triggering circuit is connected to the triggering unit, and the other end of the triggering circuit is grounded or connected to a power supply. When the first switching unit and the second switching unit are closed simultaneously, the triggering unit generates a fuse-breaking signal.

[0010] According to some embodiments of the present invention, the triggering unit includes a third switching unit, the input terminal of the third switching unit is connected to the power supply terminal of the fuse and the control module respectively, the output terminal of the third switching unit is grounded, and one end of the trigger circuit is connected to the controlled terminal of the third switching unit.

[0011] According to some embodiments of the present invention, the third switching unit includes a semiconductor switching transistor Q2, a semiconductor thyristor Q1, and a capacitor C4. The input terminal of the switching transistor Q2 is connected to a power supply, the output terminal of the switching transistor Q2 is connected to one end of the capacitor C4 and the controlled terminal of the thyristor Q1, one end of the trigger circuit is connected to the controlled terminal of the switching transistor Q2, the input terminal of the thyristor Q1 is connected to the fuse and the power supply terminal of the control module, and the output terminal of the thyristor Q1 and the other end of the capacitor C4 are both grounded.

[0012] According to some embodiments of the present invention, the electrostatic spray gun explosion-proof protection device further includes diode D3 and diode D4. The first switching unit includes a semiconductor switching transistor Q4. The switching transistor Q4 and the second switching unit are connected in series to form at least part of the trigger circuit. The positive terminal of the diode D3 is connected to the input judgment module, the positive terminal of the diode D4 is connected to the output judgment module, and the controlled terminal of the switching transistor Q4 is connected to the negative terminals of the diode D3 and the diode D4, respectively.

[0013] According to some embodiments of the present invention, the delay module includes a power-on delay unit and a power-off delay unit. The power-on delay unit is connected to the power supply terminal of the control module and the controlled terminal of the second switching unit, respectively. When the power supply terminal of the control module is powered on, the power-on delay unit maintains the second switching unit in an open state during a first delay period and controls the second switching unit to be turned on after the first delay period. The power-off delay unit is connected to the power supply terminal of the control module and the controlled terminal of the second switching unit, respectively. When the power supply terminal of the control module is de-energized, the power-off delay unit first switches the second switching unit to an open state and maintains the open state of the second switching unit during a second delay period.

[0014] According to some embodiments of the present invention, the power-on delay unit includes a resistor R19 and an energy storage capacitor C12. One end of the resistor R19 is connected to the input power supply, and the other end of the resistor R19 is connected to one end of the energy storage capacitor C12 and the controlled end of the second switching unit, respectively. The other end of the energy storage capacitor C12 is grounded.

[0015] According to some embodiments of the present invention, the electrostatic spray gun explosion-proof protection device further includes a semiconductor switching transistor Q7 and a semiconductor switching transistor Q9. The input judgment module includes a comparator U1, a resistor R2, a diode D1, a resistor R7, and a resistor R10. The first input terminal of the comparator U1 is connected to one end of the resistor R7, one end of the resistor R10, the input terminal of the switching transistor Q7, and the negative terminal of the diode D1. The other end of the resistor R7 is connected to the power supply terminal of the control module. The second input terminal of the comparator U1 is connected to a first reference voltage source. The positive terminal of the diode D1 is connected to one end of the resistor R2. The output terminal of the comparator U1 is connected to the other end of the resistor R2 and the controlled terminal of the first switching unit. The controlled terminal of the switching transistor Q7 is connected to the input terminal of the switching transistor Q9 and the power supply. The controlled terminal of the switching transistor Q9 is connected to the other end of the resistor R19 and one end of the energy storage capacitor C12. The other end of the resistor R10, the output terminal of the switching transistor Q7, and the output terminal of the switching transistor Q9 are all grounded.

[0016] According to some embodiments of the present invention, the power-off delay unit includes a diode D6, an energy storage capacitor C9, a resistor R17, a semiconductor switch Q5, a resistor R20, and a semiconductor switch Q6. The anode of the diode D6 and the controlled terminal of the switch Q5 are both connected to the input power supply. The cathode of the diode D6 is connected to one end of the resistor R17 and one end of the capacitor C9, respectively. The input terminal of the switch Q5 is connected to the other end of the resistor R17. The output terminal of the switch Q5 is connected to one end of the resistor R20 and the controlled terminal of the switch Q6, respectively. The input terminal of the switch Q6 is connected to the controlled terminal of the second switching unit. The output terminal of the switch Q6, the other end of the resistor R20, and the other end of the capacitor C9 are all grounded.

[0017] According to some embodiments of the present invention, the output judgment module includes a comparator U2, a resistor R15, a diode D5, a resistor R12, and a resistor R13. The first input terminal of the comparator U2 is connected to one end of the resistor R12, one end of the resistor R13, and the negative terminal of the diode D5, respectively. The other end of the resistor R12 is connected to the output terminal of the control module. The second input terminal of the comparator U2 is connected to a second reference voltage source. The positive terminal of the diode D5 is connected to one end of the resistor R15. The output terminal of the comparator U2 is connected to the other end of the resistor R15 and the controlled terminal of the first switching unit, respectively. The other end of the resistor R13 is grounded.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 This is a schematic diagram of the principle structure of one embodiment of the explosion-proof protection device of the present invention;

[0021] Figure 2 This is a circuit diagram of one embodiment of the explosion-proof protection device of the present invention.

[0022] Figure label:

[0023] Control module 100; fuse 200; input judgment module 300; output judgment module 400; trigger module 500; first switch unit 510; second switch unit 520; third switch unit 530; delay module 600; power-on delay unit 610; power-off delay unit 620; electrostatic spray gun 700; processing module 800. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] In the description of this invention, it should be understood that the orientation descriptions, such as the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer", indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] like Figure 1 , 2As shown, an explosion-proof protection device for an electrostatic spray gun 700 according to a first aspect embodiment of the present invention includes a control module 100, a fuse 200, an input judgment module 300, an output judgment module 400, a trigger module 500, and a delay module 600. The output terminal of the control module 100 is connected to the electrostatic spray gun 700, and the control module 100 is capable of outputting a driving voltage to control the operation of the electrostatic spray gun 700. The fuse 200 is connected to both an input power supply and the power supply terminal of the control module 100. The input power supply provides an input voltage to the control module 100 through the fuse 200. The input judgment module 300 is connected to the power supply terminal of the control module 100 to obtain the input voltage. When the input voltage is greater than a first threshold, the input judgment module 300 outputs a first trigger signal. The output judgment module 400 is connected to the output terminal of the control module 100 to obtain a driving voltage. When the driving voltage is greater than a second threshold, the output judgment module 400 outputs a first trigger signal. The output judgment module 400 outputs a second trigger signal. The trigger module 500 is connected to the input judgment module 300 and the output judgment module 400 respectively. When the trigger module 500 receives either the first trigger signal or the second trigger signal, the trigger module 500 generates a fuse signal. The trigger module 500 is connected to the fuse 200 so that the fuse 200 melts through the fuse signal. The delay module 600 is connected to the power supply terminal of the control module 100 and the trigger module 500 respectively. When the power supply terminal of the control module 100 is powered on, the delay module 600 controls the trigger module 500 to remain in a locked state during the first delay period. When the power supply terminal of the control module 100 is de-powered, the delay module 600 controls the trigger module 500 to remain in a locked state during the second delay period. In the locked state, the trigger module 500 does not generate a fuse signal.

[0029] The fuse 200 can be selected from conventional fuses and other components. The control module 100 may include a power modulation circuit. The input terminal of the power modulation circuit is connected to the input power supply through the fuse 200. The power modulation circuit modulates a suitable driving voltage according to the power requirements of different specifications of electrostatic spray guns 700. In addition, the explosion-proof protection device may also include a processing module 800. The processing module 800 may include an MCU or CPU and its auxiliary circuits. Specifically, the processing module 800 can also acquire the fuse signal and save the fault information for subsequent analysis and maintenance.

[0030] The electrostatic spray gun 700 explosion-proof protection device of the present invention, during operation, the input judgment module 300 acquires the input voltage. When the input voltage is greater than a first threshold, it outputs a first trigger signal. Similarly, the output judgment module 400 acquires the driving voltage. When the driving voltage is greater than a second threshold, it outputs a second trigger signal. Either the first trigger signal or the second trigger signal can cause the trigger module 500 to generate a fuse signal, and the fuse signal is used to melt the fuse element 200, thereby making the electrostatic spray gun 700 safe to use. Meanwhile, the control module 100... At the moment of power failure or loss of power, the delay module 600 keeps the trigger module 500 in a locked state during the first delay period after power is restored and the second delay period after power failure. In the locked state, the trigger module 500 does not generate a fuse signal, thus preventing the fuse 200 from blowing. Furthermore, in the initial stage of power restoration, the control module 100 has not yet completed the modulation of the drive voltage, so the drive voltage will not be too high and cause the electrostatic spray gun 700 to go out of control. Similarly, the electrostatic spray gun 700 will not go out of control when power is lost. Therefore, this design is reliable and stable in operation, and the electrostatic spray gun 700 is safe to use.

[0031] In some embodiments of the present invention, such as Figure 2 As shown, the trigger module 500 includes a first switch unit 510, a second switch unit 520, and a trigger unit. The first switch unit 510 and the second switch unit 520 are connected in series to form at least a partial trigger circuit. The controlled terminal of the first switch unit 510 is connected to the input judgment module 300 and the output judgment module 400, respectively. When the controlled terminal of the first switch unit 510 receives either a first trigger signal or a second trigger signal, the first switch unit 510 is triggered to switch on or off. The controlled terminal of the second switch unit 520 is connected to the delay module 600. The delay module 600 can trigger the second switch unit 520 to switch on or off. One end of the trigger circuit is connected to the trigger unit, and the other end of the trigger circuit is grounded or connected to a power supply. When the first switch unit 510 and the second switch unit 520 are closed or opened simultaneously, the trigger unit generates a fuse signal.

[0032] A trigger circuit is formed by connecting the first switch unit 510 and the second switch unit 520 in series. The trigger unit generates a fuse signal only when the first switch unit 510 and the second switch unit 520 are closed or opened simultaneously. The input judgment module 300 and the output judgment module 400 control the on / off state of the first switch unit 510, and the delay module 600 controls the on / off state of the second switch unit 520. The control of any one of the delay module 600, the input judgment module 300, and the output judgment module 400 is independent of each other and does not interfere with each other, making the control more stable and reliable.

[0033] In some embodiments of the present invention, such as Figure 2 As shown, the triggering unit includes a third switch unit 530. The input terminal of the third switch unit 530 is connected to the power supply terminal of the fuse 200 and the control module 100, respectively. The output terminal of the third switch unit 530 is grounded. One end of the trigger circuit is connected to the controlled terminal of the third switch unit 530.

[0034] When the first switch unit 510 and the second switch unit 520 are closed at the same time, the third switch unit 530 is turned on. At this time, the current output by the input power supply is directly grounded after passing through the fuse 200. The large current can melt the fuse 200, thereby providing explosion protection for the electrostatic spray gun 700.

[0035] It should be noted that when either the first switch unit 510 or the second switch unit 520 is closed and the other is open, the third switch unit 530 will not be turned on.

[0036] Specifically, the third switching unit 530 includes a semiconductor switching transistor Q2, a semiconductor thyristor Q1, and a capacitor C4. The input terminal of the switching transistor Q2 is connected to the power supply, and the output terminal of the switching transistor Q2 is connected to one end of the capacitor C4 and the controlled terminal of the thyristor Q1. One end of the trigger circuit is connected to the controlled terminal of the switching transistor Q2. The input terminal of the thyristor Q1 is connected to the power supply terminal of the fuse 200 and the control module 100. The output terminal of the thyristor Q1 and the other end of the capacitor C4 are both grounded.

[0037] The switching transistor Q2 is a P-type switching transistor. When the first switching unit 510 and the second switching unit 520 are closed simultaneously, the controlled terminal of the switching transistor Q2 is grounded, and the switching transistor Q2 is turned on. The power supply provides a high level to trigger the thyristor Q1 to turn on. The current output by the input power supply is grounded after passing through the fuse 200 and the thyristor Q1. Alternatively, the switching transistor Q2 is an N-type switching transistor. When the first switching unit 510 and the second switching unit 520 are closed simultaneously, the controlled terminal of the switching transistor Q2 is connected to the power supply, and the switching transistor Q2 is turned on.

[0038] The capacitor C4 is chosen to have a large capacitance value. When the switch Q2 is turned on, a lot of energy can be stored at the capacitor C4. Even if the switch Q2 is turned off for other reasons after it is turned on, the voltage at the capacitor C4 is sufficient to keep the thyristor Q1 on for a period of time until the fuse 200 blows.

[0039] Specifically, the processing module 800 also includes a switching transistor Q3. The controlled terminal of the switching transistor Q3 is connected to the output terminal of the switching transistor Q2, one end of the capacitor C4, and the controlled terminal of the thyristor Q1, respectively. The input terminal of the switching transistor Q3 is connected to the power supply and the MCU or CPU, respectively. The output terminal of the switching transistor Q3 is grounded.

[0040] In some embodiments of the present invention, the electrostatic spray gun 700 explosion-proof protection device further includes diodes D3 and D4. The first switching unit 510 includes a semiconductor switching transistor Q4. The switching transistor Q4 and the second switching unit 520 are connected in series to form at least part of the trigger circuit. The positive terminal of the diode D3 is connected to the input judgment module 300, and the positive terminal of the diode D4 is connected to the output judgment module 400. The controlled terminal of the switching transistor Q4 is connected to the negative terminals of the diodes D3 and D4, respectively.

[0041] The switching transistor Q4 can be an N-type or P-type switching transistor. Specifically, a corresponding high-level or low-level signal is generated based on the switching characteristics of the switching transistor for triggering. This will not be elaborated here. In addition, other switching transistor components in this design can also be selected accordingly.

[0042] By utilizing the unidirectional conduction characteristics of diodes D3 and D4, either the first trigger signal or the second trigger signal can cause the trigger module 500 to generate a fuse-breaking signal. Furthermore, the first trigger signal and the second trigger signal will not interfere with the corresponding input judgment module 300 and output judgment module 400, ensuring stable and reliable control.

[0043] In some embodiments of the present invention, such as Figure 2 As shown, the delay module 600 includes a power-on delay unit 610 and a power-off delay unit 620. The power-on delay unit 610 is connected to the power supply terminal of the control module 100 and the controlled terminal of the second switch unit 520, respectively. When the power supply terminal of the control module 100 is powered on, the power-on delay unit 610 maintains the second switch unit 520 in the off state during the first delay period and controls the second switch unit 520 to turn on after the first delay period.

[0044] When the power supply terminal of the control module 100 is powered on, it triggers the power-on delay unit 610 to perform a delay. For example, the second switching unit 520 is a semiconductor switching transistor Q8. Switching transistor Q8 is an N-type switching transistor. The initial state of switching transistor Q8 is off. During the first delay period, the power-on delay unit 610 maintains the off state of switching transistor Q8 and provides a high level to the controlled terminal of switching transistor Q8 after the first delay period, so that switching transistor Q8 is turned on. Similarly, if switching transistor Q8 is a P-type switching transistor, the initial state of switching transistor Q8 is on. The power-on delay unit 610 needs to switch switching transistor Q8 to the off state first, maintain the off state of switching transistor Q8 during the first delay period, and control switching transistor Q8 to turn on after the first delay period.

[0045] The power failure delay unit 620 is connected to the power supply terminal of the control module 100 and the controlled terminal of the second switch unit 520 respectively. When the power supply terminal of the control module 100 loses power, the power failure delay unit 620 first switches the second switch unit 520 to the off state and maintains the off state of the second switch unit 520 during the second delay period.

[0046] When the power supply to the control module 100 fails, the power failure delay unit 620 performs a delay. During the power-on process, the switch Q8 is in the on state. At the moment of power failure, the power failure delay unit 620 needs to switch the switch Q8 to the off state first, and maintain the off state of the switch Q8 during the second delay period. It should be noted that the switch Q8 can be an N-type switch. At the moment of power failure, the power failure delay unit 620 needs to quickly provide a low level to the controlled terminal of the switch Q8 to maintain the off state of the switch Q8. After the second delay period, there may still be a small amount of electrical energy in the explosion-proof protection device, which can drive the switch Q8 to turn on again. However, at this time, the input power supply has stopped, and it is unlikely to cause the fuse 200 to blow. This method is also within the protection scope of this design. If the switch Q8 is a P-type switch, at the moment of power failure, the power failure delay unit 620 needs to quickly provide a high level to the controlled terminal of the switch Q8 to maintain the off state of the switch Q8 during the second delay period.

[0047] Specifically, the power-on delay unit 610 includes a resistor R19 and an energy storage capacitor C12. One end of the resistor R19 is connected to the input power supply, and the other end of the resistor R19 is connected to one end of the energy storage capacitor C12 and the controlled end of the second switching unit 520, respectively. The other end of the energy storage capacitor C12 is grounded.

[0048] When the power supply terminal of the control module 100 is powered on, the electrical energy charges the energy storage capacitor C12. In the initial stage of power-on, the energy storage voltage of the energy storage capacitor C12 is low and fails to trigger the second switching unit 520 to conduct. The second switching unit 520 remains in the off state. After the first delay period, the energy storage voltage of the energy storage capacitor C12 increases, causing the second switching unit 520 to conduct. The time of the first delay period can be changed by setting the parameters of the resistor R19 and the energy storage capacitor C12. Manufacturers can set it according to actual needs.

[0049] In some embodiments of the present invention, such as Figure 2As shown, the electrostatic spray gun 700 explosion-proof protection device also includes semiconductor switching transistors Q7 and Q9. The input judgment module 300 includes a comparator U1, a resistor R2, a diode D1, a resistor R7, and a resistor R10. The first input terminal of the comparator U1 is connected to one end of the resistor R7, one end of the resistor R10, the input terminal of the switching transistor Q7, and the cathode of the diode D1. The other end of the resistor R7 is connected to the power supply terminal of the control module 100. The second input terminal of the comparator U1 is connected to the first reference voltage. The source connection is as follows: the positive terminal of the diode D1 is connected to one end of the resistor R2; the output terminal of the comparator U1 is connected to the other end of the resistor R2 and the controlled terminal of the first switching unit 510; the controlled terminal of the switching transistor Q7 is connected to the input terminal of the switching transistor Q9 and the power supply; the controlled terminal of the switching transistor Q9 is connected to the other end of the resistor R19 and one end of the energy storage capacitor C12; and the other end of the resistor R10, the output terminal of the switching transistor Q7, and the output terminal of the switching transistor Q9 are all grounded.

[0050] The input voltage output from the input power supply is divided by resistors R7 and R10 to provide a sampled value of the input voltage to the first input terminal of comparator U1. The voltage value of the first reference voltage source can be set according to the manufacturer and the actual needs of the electrostatic spray gun 700. For example, when the sampled value of the input voltage is greater than the first threshold, comparator U1 outputs a high level to form the first trigger signal.

[0051] Resistor R2 and diode D1 provide a hysteresis voltage for comparator U1, so that comparator U1 can maintain a high output level when the sampled value of the input voltage is greater than the first threshold.

[0052] In the initial stage of powering on the control module 100, there may be fluctuations in the input voltage. Since the control module 100 has not completed modulation in the initial stage of powering on, the output drive voltage is usually low and will not exceed the second threshold. Therefore, in the initial stage of powering on, the energy storage voltage of the energy storage capacitor C12 is low, and the switching transistor Q9 drives the switching transistor Q7 to conduct, thereby pulling down the voltage of the first input terminal of the comparator U1 to prevent false triggering.

[0053] Specifically, both switch Q9 and switch Q7 can be N-type switches. Of course, with appropriate circuit modifications, P-type switches can also be selected.

[0054] In some embodiments of the present invention, such as Figure 2As shown, the power-off delay unit 620 includes a diode D6, an energy storage capacitor C9, a resistor R17, a semiconductor switch Q5, a resistor R20, and a semiconductor switch Q6. The anode of the diode D6 and the controlled terminal of the switch Q5 are both connected to the input power supply. The cathode of the diode D6 is connected to one end of the resistor R17 and one end of the capacitor C9, respectively. The input terminal of the switch Q5 is connected to the other end of the resistor R17. The output terminal of the switch Q5 is connected to one end of the resistor R20 and the controlled terminal of the switch Q6, respectively. The input terminal of the switch Q6 is connected to the controlled terminal of the second switch unit 520. The output terminal of the switch Q6, the other end of the resistor R20, and the other end of the capacitor C9 are all grounded.

[0055] Switch Q5 can be a P-type switch, and switch Q6 can be an N-type switch. During the power-on process, the power supply charges the energy storage capacitor C9. At the moment of power failure, switch Q5 turns on, and the energy storage capacitor C9 can provide a high level to the controlled terminal of switch Q6, turning on switch Q6, thereby pulling down the level of the controlled terminal of switch Q8, so that switch Q8 remains off.

[0056] In some embodiments of the present invention, such as Figure 2 As shown, the output judgment module 400 includes a comparator U2, a resistor R15, a diode D5, a resistor R12, and a resistor R13. The first input terminal of the comparator U2 is connected to one end of the resistor R12, one end of the resistor R13, and the negative terminal of the diode D5. The other end of the resistor R12 is connected to the output terminal of the control module 100. The second input terminal of the comparator U2 is connected to the second reference voltage source. The positive terminal of the diode D5 is connected to one end of the resistor R15. The output terminal of the comparator U2 is connected to the other end of the resistor R15 and the controlled terminal of the first switching unit 510. The other end of the resistor R13 is grounded.

[0057] The driving voltage output by the control module 100 is divided by resistors R12 and R13 to provide a sampled value of the input voltage to the first input terminal of comparator U2. The voltage value of the second reference voltage source can be set according to the manufacturer and the actual needs of the electrostatic spray gun 700. For example, when the sampled value of the driving voltage is greater than the second threshold, comparator U2 outputs a high level to form a second trigger signal.

[0058] Resistor R5 and diode D15 provide hysteresis voltage for comparator U2, so that comparator U2 can maintain a high output level when the sampled value of the drive voltage is greater than the second threshold.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An explosion-proof protection device for an electrostatic spray gun, characterized in that, include: A control module is used to connect to the electrostatic spray gun, and the control module is capable of outputting a drive voltage to control the operation of the electrostatic spray gun; A fuse is used to connect to the input power supply and the power supply terminal of the control module respectively. The input power supply provides the input voltage to the control module through the fuse. An input judgment module is connected to the power supply terminal of the control module to obtain the input voltage. When the input voltage is greater than a first threshold, the input judgment module outputs a first trigger signal. An output judgment module is connected to the output terminal of the control module to obtain the driving voltage. When the driving voltage is greater than the second threshold, the output judgment module outputs a second trigger signal. The trigger module is connected to the input judgment module and the output judgment module respectively. When the trigger module receives either the first trigger signal or the second trigger signal, the trigger module generates a fuse signal. The trigger module is connected to the fuse element so that the fuse element melts through the fuse signal. The delay module is connected to the power supply terminal of the control module and the trigger module respectively. When the power supply terminal of the control module is powered on, the delay module controls the trigger module to remain in the locked state during the first delay period. When the power supply terminal of the control module is de-powered, the delay module controls the trigger module to remain in the locked state during the second delay period. In the locked state, the trigger module does not generate a fuse signal.

2. The explosion-proof protection device for an electrostatic spray gun according to claim 1, characterized in that: The triggering module includes a first switch unit, a second switch unit, and a triggering unit. The first switch unit and the second switch unit are connected in series to form at least a partial triggering circuit. The controlled terminal of the first switch unit is connected to the input judgment module and the output judgment module, respectively. When the controlled terminal of the first switch unit receives either a first trigger signal or a second trigger signal, the first switch unit is triggered to switch on or off. The controlled terminal of the second switch unit is connected to the delay module, which can trigger the second switch unit to switch on or off. One end of the triggering circuit is connected to the triggering unit, and the other end of the triggering circuit is grounded or connected to a power supply. When the first switch unit and the second switch unit are closed simultaneously, the triggering unit generates a fuse signal.

3. The electrostatic spray gun explosion-proof protection device according to claim 2, characterized in that: The triggering unit includes a third switching unit. The input terminal of the third switching unit is connected to the power supply terminal of the fuse and the control module, respectively. The output terminal of the third switching unit is grounded. One end of the trigger circuit is connected to the controlled terminal of the third switching unit.

4. The explosion-proof protection device for an electrostatic spray gun according to claim 3, characterized in that: The third switching unit includes a semiconductor switching transistor Q2, a semiconductor thyristor Q1, and a capacitor C4. The input terminal of the switching transistor Q2 is connected to the power supply. The output terminal of the switching transistor Q2 is connected to one end of the capacitor C4 and the controlled terminal of the thyristor Q1. One end of the trigger circuit is connected to the controlled terminal of the switching transistor Q2. The input terminal of the thyristor Q1 is connected to the fuse and the power supply terminal of the control module. The output terminal of the thyristor Q1 and the other end of the capacitor C4 are both grounded.

5. The explosion-proof protection device for an electrostatic spray gun according to claim 2, characterized in that, It also includes diodes D3 and D4. The first switching unit includes a semiconductor switching transistor Q4. The switching transistor Q4 and the second switching unit are connected in series to form at least part of the trigger circuit. The positive terminal of the diode D3 is connected to the input judgment module, and the positive terminal of the diode D4 is connected to the output judgment module. The controlled terminal of the switching transistor Q4 is connected to the negative terminals of the diodes D3 and D4, respectively.

6. The explosion-proof protection device for an electrostatic spray gun according to claim 2, characterized in that, The delay module includes a power-on delay unit and a power-off delay unit. The power-on delay unit is connected to the power supply terminal of the control module and the controlled terminal of the second switch unit, respectively. When the power supply terminal of the control module is powered on, the power-on delay unit maintains the second switch unit in the off state during the first delay period and controls the second switch unit to be turned on after the first delay period. The power failure delay unit is connected to the power supply terminal of the control module and the controlled terminal of the second switching unit respectively. When the power supply terminal of the control module loses power, the power failure delay unit first switches the second switching unit to the off state and maintains the off state of the second switching unit during the second delay period.

7. The explosion-proof protection device for an electrostatic spray gun according to claim 6, characterized in that, The power-on delay unit includes a resistor R19 and an energy storage capacitor C12. One end of the resistor R19 is connected to the input power supply, and the other end of the resistor R19 is connected to one end of the energy storage capacitor C12 and the controlled end of the second switching unit. The other end of the energy storage capacitor C12 is grounded.

8. The explosion-proof protection device for an electrostatic spray gun according to claim 7, characterized in that, It also includes semiconductor switching transistors Q7 and Q9. The input judgment module includes comparator U1, resistor R2, diode D1, resistor R7, and resistor R10. The first input terminal of comparator U1 is connected to one end of resistor R7, one end of resistor R10, the input terminal of switching transistor Q7, and the negative terminal of diode D1. The other end of resistor R7 is connected to the power supply terminal of the control module. The second input terminal of comparator U1 is connected to the first reference voltage source. The positive terminal of diode D1 is connected to one end of resistor R2. The output terminal of comparator U1 is connected to the other end of resistor R2 and the controlled terminal of the first switching unit. The controlled terminal of switching transistor Q7 is connected to the input terminal of switching transistor Q9 and the power supply. The controlled terminal of switching transistor Q9 is connected to the other end of resistor R19 and one end of energy storage capacitor C12. The other end of resistor R10, the output terminal of switching transistor Q7, and the output terminal of switching transistor Q9 are all grounded.

9. The electrostatic spray gun explosion-proof protection device according to claim 6, characterized in that, The power-off delay unit includes a diode D6, an energy storage capacitor C9, a resistor R17, a semiconductor switch Q5, a resistor R20, and a semiconductor switch Q6. The anode of the diode D6 and the controlled terminal of the switch Q5 are both connected to the input power supply. The cathode of the diode D6 is connected to one end of the resistor R17 and one end of the capacitor C9. The input terminal of the switch Q5 is connected to the other end of the resistor R17. The output terminal of the switch Q5 is connected to one end of the resistor R20 and the controlled terminal of the switch Q6. The input terminal of the switch Q6 is connected to the controlled terminal of the second switching unit. The output terminal of the switch Q6, the other end of the resistor R20, and the other end of the capacitor C9 are all grounded.

10. The electrostatic spray gun explosion-proof protection device according to claim 2, characterized in that, The output judgment module includes a comparator U2, a resistor R15, a diode D5, a resistor R12, and a resistor R13. The first input terminal of the comparator U2 is connected to one end of the resistor R12, one end of the resistor R13, and the negative terminal of the diode D5. The other end of the resistor R12 is connected to the output terminal of the control module. The second input terminal of the comparator U2 is connected to a second reference voltage source. The positive terminal of the diode D5 is connected to one end of the resistor R15. The output terminal of the comparator U2 is connected to the other end of the resistor R15 and the controlled terminal of the first switching unit. The other end of the resistor R13 is grounded.

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