Automatic control circuit for gas delay of plasma cutting machine

Abstract

The invention discloses a gas delay automatic control circuit of a plasma cutting machine, belongs to the technical field of plasma cutting machines, and aims to solve the technical problem of delay time control. According to the technical scheme, a temperature sampling module is connected with a voltage conversion module and used for collecting the temperature of a cutting gun nozzle, converting the temperature into an electric signal and inputting the electric signal to the voltage conversion module; the voltage conversion module is connected with the delay control module and is used for judging and converting the electric signal into a first control signal to be transmitted to the delay control module; the delay control module is connected with the execution module and is used for receiving the second control operation and the first control signal and outputting a delay execution signal; the execution module comprises an electromagnetic valve, starting and stopping of the electromagnetic valve are controlled according to the delay execution signal, the gas delay time is controlled according to the temperature of the cutting torch, the service life of the cutting torch can be prolonged to a certain degree, a user does not need to adjust the cutting torch by himself, and convenience and experience of the user are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma cutters, and in particular to a gas delay automatic control circuit for a plasma cutter. Background Art

[0002] Gas control in a plasma cutter means that after the gas is ejected, it takes a certain period of time to form a plasma and start cutting. This delay phenomenon is normal in plasma cutters, and the main reasons are as follows:

[0003] It takes time for the gas to form a plasma: After the switch is pressed, the gas needs a certain amount of time to form a plasma in the cutting torch, and this process usually takes about 2 seconds. The gas is ionized in the cutting torch to form a plasma, and only then can sufficient energy be generated for cutting.

[0004] Delayed cooling: After cutting is completed, the gas will still be ejected for a period of time to cool components such as the electrode and nozzle of the cutting torch, preventing them from being damaged due to high temperature.

[0005] Arc ignition process: During the arc ignition stage, the gas delay can help stabilize the arc and avoid poor cutting effects caused by unstable gas pressure.

[0006] In existing products, there is no solution to automatically regulate this delay control to improve the performance. Summary of the Invention

[0007] To solve the above technical problems and drawbacks, in view of the fact that the gas delay adjustment time of the existing air plasma cutter cannot be adjusted according to the temperature of the nozzle, this circuit has invented a new control circuit for this problem. It can control the gas delay time according to the temperature of the cutting nozzle, which will extend the service life of the cutting torch to a certain extent, and does not require the user to adjust it himself, greatly improving the convenience and experience of the user.

[0008] To achieve the above object and other related objects, the present invention adopts the following technical solutions:

[0009] A gas delay automatic control circuit for a plasma cutter, including a temperature sampling module, a voltage conversion module, a delay control module, and an execution module.

[0010] The temperature sampling module is connected to the voltage conversion module and is used to collect the temperature of the cutting nozzle and convert it into an electrical signal, and input the electrical signal to the voltage conversion module.

[0011] The voltage conversion module is connected to the delay control module and is used to judge and convert the electrical signal into a first control signal for the delay control module.

[0012] The delay control module is connected to the execution module, and is used to receive the second control operation and the first control signal, and output a delayed execution signal;

[0013] The execution module includes a solenoid valve, and controls the start and stop of the solenoid valve according to the delayed execution signal.

[0014] Preferably, the temperature sampling module includes an NTC thermocouple sensor, an interface, a resistor R3, a capacitor C1, and a resistor R6. The NTC thermocouple sensor is connected through the interface. One end of the interface is connected to the first voltage source, and the other end of the interface is connected to the resistor R3, the resistor R6, and the capacitor C1. The other end of the resistor R3 and the other end of the capacitor C1 are grounded, and the other end of the resistor R6 is used as the output of the electrical signal.

[0015] Preferably, the voltage conversion module includes a resistor R7, a resistor R10, a resistor R12, a resistor R11, a resistor R13, a diode D4, a comparator U2, and a diode D3. One end of the resistor R7 is connected to the first voltage source, and the other end of the resistor R7 is connected to one end of the resistor R10, one end of the resistor R11, and the non-inverting input terminal of the comparator U2. The other end of the resistor R10 is grounded through the resistor R12. The other end of the resistor R11 is connected to the anode of the diode D4 through the resistor R13. The cathode of the diode D4 is connected to the output terminal of the comparator U2 and the cathode of the diode D3. The anode of the diode D3 is used as the output of the first control signal.

[0016] Preferably, the delay control module includes a resistor R2, a capacitor C3, a switch S1, a resistor R9, an optocoupler U1, a resistor R4, a resistor R5, a resistor R8, a capacitor C4, a capacitor C5, and a triode Q2. The second voltage source is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to one end of the capacitor C3 and the anode of the optocoupler U1. The other end of the capacitor C3 is connected to the cathode of the optocoupler U1 and one end of the switch S1. The other end of the switch S1 is grounded through the resistor R9. The second voltage source is also connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the collector of the optocoupler U1 and one end of the resistor R5. The other end of the resistor R5 is connected to one end of the resistor R8, one end of the capacitor C4, the base of the triode Q2, and one end of the capacitor C5. The emitter of the optocoupler U1, the other end of the resistor R8, the other end of the capacitor C4, the other end of the capacitor C5, and the emitter of the triode Q2 are commonly grounded. The base of the triode Q2 receives the first control signal, and the collector of the triode Q2 is used to connect to the execution module.

[0017] Preferably, the execution module includes a solenoid valve, a diode D1, a MOS transistor Q1, a resistor R1, a voltage regulator diode ZD1, a capacitor C2, and a diode D2. One end of the second voltage source is connected to one end of the solenoid valve, the cathode of the diode D1, and one end of the resistor R1. The other end of the solenoid valve is connected to the anode of the diode D1 and the drain of the MOS transistor Q1. The other end of the resistor R1 is connected to the cathode of the voltage regulator diode ZD1, the anode of the diode D2, the positive electrode of the capacitor C2, the anode of the voltage regulator diode ZD1, and the gate of the MOS transistor Q1. The negative electrode of the capacitor C2 is grounded. The cathode of the diode D2 is connected to the collector of the triode Q2 for controlling the on-off of the solenoid valve.

[0018] Preferably, the capacitor C2 is an electrolytic capacitor.

[0019] In summary, the present invention includes at least one of the following beneficial technical effects:

[0020] The temperature sampling module collects the temperature of the cutting torch nozzle and converts it into an electrical signal. In this way, the ambient temperature of the cutting torch nozzle can be first converted into a resistance value, and then the resistance value is converted into an electrical signal. According to the electrical signal, the voltage conversion module further amplifies and compares the electrical signal, thereby improving the reliability and stability of signal transmission. At this time, combined with the signal given by the delay control module, the execution module is jointly controlled to work. Only when the delay control module gives a signal and the voltage conversion module also gives a signal, the execution module triggers the ground connection to 0V, and thus the solenoid valve is energized to work. It aims at the problem that the gas delay adjustment time of the existing air plasma cutting machine cannot be adjusted according to the nozzle temperature for cooling. This solution can control the gas delay time according to the temperature of the cutting nozzle, which will extend the service life of the cutting torch to a certain extent, and there is no need for the user to adjust it by himself, greatly improving the convenience and experience of the user. Description of the Drawings

[0021] Figure 1 is the block diagram of the module connection of the embodiment of the present invention;

[0022] Figure 2 is the first part of the circuit diagram of the embodiment of the present invention;

[0023] Figure 3 is the second part of the circuit diagram of the embodiment of the present invention.

[0024] Description of the reference numerals of the main components:

[0025] 100. Temperature sampling module; 200. Voltage conversion module; 300. Delay control module; 400. Execution module. Detailed Embodiment

[0026] The following describes the implementation manners of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0027] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present invention. The diagrams only show the components related to the present invention, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and ratios of the components in actual implementation can be changed arbitrarily, and the component layout type may also be more complex.

[0028] The following further illustrates the specific implementation manners of the present invention with reference to the accompanying drawings.

[0029] Embodiment:

[0030] An embodiment of the present invention discloses a gas delay automatic control circuit for a plasma cutting machine. Referring to Figure 1 as shown, it includes a temperature sampling module 100, a voltage conversion module 200, a delay control module 300, and an execution module 400.

[0031] The temperature sampling module 100 is connected to the voltage conversion module 200 and is used to collect the temperature of the cutting torch nozzle and convert it into an electrical signal, and input the electrical signal to the voltage conversion module 200; the voltage conversion module 200 is connected to the delay control module 300 and is used to judge and convert the electrical signal into a first control signal for the delay control module 300; the delay control module 300 is connected to the execution module 400 and is used to receive a second control operation and the first control signal, and output a delay execution signal; the execution module 400 includes an electromagnetic valve and controls the start and stop of the electromagnetic valve according to the delay execution signal.

[0032] Combined with Figure 2 and Figure 3As shown, specifically, the temperature sampling module 100 includes an NTC thermocouple sensor, interface P1, resistor R3, capacitor C1, and resistor R6. The NTC thermocouple sensor is connected through interface P1. One end of interface P1 is connected to the first voltage source, and the other end of the interface is connected to resistor R3, resistor R6, and capacitor C1. The other end of resistor R3 and the other end of capacitor C1 are grounded, and the other end of resistor R6 serves as the output of the electrical signal. The first voltage source is a 15V voltage in this example. This voltage source is provided to the NTC thermocouple sensor for operation. Resistor R3 and capacitor C1 form a resistor-capacitor filter to effectively reduce the influence of interference signals and provide a current limit through resistor R6 to the voltage conversion module 200.

[0033] Next, specifically, the voltage conversion module 200 is as follows. The voltage conversion module 200 includes resistor R7, resistor R10, resistor R12, resistor R11, resistor R13, diode D4, comparator U2, and diode D3. One end of resistor R7 is connected to the first voltage source, and the other end of resistor R7 is connected to one end of resistor R10, one end of resistor R11, and the non-inverting input terminal of comparator U2. The other end of resistor R10 is grounded through resistor R12, and the other end of resistor R11 is connected to the anode of diode D4 through resistor R13. The cathode of diode D4 is connected to the output terminal of comparator U2 and the cathode of diode D3, and the anode of diode D3 serves as the output of the first control signal.

[0034] The model of comparator U2 for sampling is LM358. Resistors R7, R10, and R12 form a voltage-dividing signal to set a comparison reference for the non-inverting terminal of comparator U2. When the electrical signal of the temperature reaches the voltage value of the comparison reference, comparator U2 triggers an output signal. The temperature sensor monitors the temperature of the cutting nozzle in real time and feeds back the data. When the temperature exceeds the preset threshold, the gas delay time will be extended to increase the cooling effect of the cutting nozzle, thereby reducing the temperature and protecting the cutting nozzle from overheating damage. Conversely, if the temperature is lower than the threshold, the gas delay time will be correspondingly shortened to improve the cutting efficiency.

[0035] Specifically, in Figure 3Among them, the delay control module 300 includes a resistor R2, a capacitor C3, a switch S1, a resistor R9, an optocoupler U1, a resistor R4, a resistor R5, a resistor R8, a capacitor C4, a capacitor C5, and a triode Q2. The second voltage source is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C3 and the anode of the optocoupler U1, the other end of the capacitor C3 is connected to the cathode of the optocoupler U1 and one end of the switch S1, the other end of the switch S1 is grounded through the resistor R9, the second voltage source is also connected to one end of the resistor R4, the other end of the resistor R4 is connected to the collector of the optocoupler U1 and one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R8, one end of the capacitor C4, the base of the triode Q2, and one end of the capacitor C5. The emitter of the optocoupler U1, the other end of the resistor R8, the other end of the capacitor C4, the other end of the capacitor C5, and the emitter of the triode Q2 are commonly grounded. The base of the triode Q2 receives the first control signal, and the collector of the triode Q2 is used to connect to the execution module 400.

[0036] When the switch S1 is closed, at this time, the second voltage source is 24V, which makes the optocoupler U1 conduct, triggering a decrease in the potential between the resistor R4 and the resistor R5, so as to cooperate with the signal output by the voltage conversion module 200 to control the triode Q1 to conduct together. The triode Q1 is an NPN triode. When it conducts, it enables the execution module 400 to conduct to the ground (a 0V path can be achieved to conduct).

[0037] Specifically, the execution module 400 includes a solenoid valve, a diode D1, a MOS transistor Q1, a resistor R1, a zener diode ZD1, a capacitor C2, and a diode D2. The second voltage source is connected to one end of the solenoid valve, the cathode of the diode D1, and one end of the resistor R1. The other end of the solenoid valve is connected to the anode of the diode D1 and the drain of the MOS transistor Q1. The other end of the resistor R1 is connected to the cathode of the zener diode ZD1, the anode of the diode D2, the positive electrode of the capacitor C2, the anode of the zener diode ZD1, and the gate of the MOS transistor Q1. The negative electrode of the capacitor C2 is grounded. The cathode of the diode D2 is connected to the collector of the triode Q2 to control the on / off of the solenoid valve. The capacitor C2 is an electrolytic capacitor.

[0038] At this time, since the cathode of the diode D2 is in a conductive state to the ground, the current will flow in from the anode of D2. At this time, the capacitor C2 is charged for delay. When the capacitor C2 is fully charged, the zener diode ZD1 stabilizes the voltage of the gate of the MOS transistor Q1, so that the MOS gate is at a high level and works in a conductive state. After the MOS transistor Q1 conducts, at this time the solenoid valve M conducts, so as to perform deflation control. If the temperature drops and does not reach the set value, at this time the triode Q2 does not conduct, so the current does not pass through the diode D2. At this time, the capacitor C2 does not charge for delay, and the MOS transistor Q1 conducts directly, so as to directly control the solenoid valve to work for deflation.

[0039] As can be seen, the temperature sampling module 100 collects the temperature of the cutting torch nozzle and converts it into an electrical signal. In this way, the ambient temperature of the cutting torch nozzle can be first converted into a resistance value, and then the resistance value is converted into an electrical signal. According to the electrical signal, the voltage conversion module 200 is further used to amplify and compare the electrical signal, thereby improving the reliability and stability of signal transmission. At this time, combined with the signal given by the delay control module 300, the execution module 400 is jointly controlled to work. Only when the delay control module 300 gives a signal and the voltage conversion module 200 also gives a signal, the execution module 400 triggers a 0V ground connection, and thus the solenoid valve is energized to work. It aims at the problem that the gas delay adjustment time of the existing air plasma cutting machine cannot be adjusted according to the nozzle temperature. This solution can control the gas delay time according to the temperature of the cutting nozzle, which will extend the service life of the cutting torch to a certain extent, and there is no need for the user to adjust it by themselves, greatly improving the convenience and experience of the user.

[0040] When the temperature exceeds the preset threshold, the delay time of gas deflation will be extended to increase the cooling effect of the cutting nozzle, thereby reducing the temperature and protecting the cutting nozzle from overheating damage. On the contrary, if the temperature is lower than the threshold, the gas delay time will be correspondingly shortened to improve the cutting efficiency.

[0041] The above embodiments are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A gas delay automatic control circuit for a plasma cutting machine, comprising a temperature sampling module (100), a voltage conversion module (200), a delay control module (300), and an execution module (400), characterized in that: The temperature sampling module (100) is connected to the voltage conversion module (200) and is used to collect the temperature of the cutting gun nozzle and convert it into an electrical signal, and input the electrical signal to the voltage conversion module (200); The voltage conversion module (200) is connected to the delay control module (300) and is used to judge and convert the electrical signal into a first control signal to the delay control module (300); The delay control module (300) is connected to the execution module (400), and is used to receive the second control operation and the first control signal, and output a delay execution signal; The execution module (400) comprises a solenoid valve, and the start and stop of the solenoid valve are controlled according to the delayed execution signal.

2. The plasma cutting machine gas delay automatic control circuit according to claim 1, characterized in that: The temperature sampling module (100) comprises an NTC thermocouple sensor, an interface, a resistor R3, a capacitor C1 and a resistor R6; the NTC thermocouple sensor is connected via the interface; one end of the interface is connected to a first voltage source; the other end of the interface is connected to the resistor R3, the resistor R6 and the capacitor C1; the other end of the resistor R3 and the other end of the capacitor C1 are grounded; and the other end of the resistor R6 is used as an output of an electrical signal.

3. The gas delay automatic control circuit for a plasma cutting machine according to claim 1, characterized in that: The voltage conversion module (200) comprises a resistor R7, a resistor R10, a resistor R12, a resistor R11, a resistor R13, a diode D4, a comparator U2 and a diode D3, one end of the resistor R7 is connected to a first voltage source, the other end of the resistor R7 is connected to one end of the resistor R10, one end of the resistor R11 and the non-inverting input end of the comparator U2, the other end of the resistor R10 is grounded via the resistor R12, the other end of the resistor R11 is connected to the anode of the diode D4 via the resistor R13, the cathode of the diode D4 is connected to the output end of the comparator U2 and the cathode of the diode D3, and the anode of the diode D3 is output as a first control signal.

4. The gas delay automatic control circuit for a plasma cutting machine according to claim 3, characterized in that: The delay control module (300) comprises a resistor R2, a capacitor C3, a switch S1, a resistor R9, an optical coupler U1, a resistor R4, a resistor R5, a resistor R8, a capacitor C4, a capacitor C5, and a transistor Q2, wherein a second voltage source is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C3 and an anode of the optical coupler U1, the other end of the capacitor C3 is connected to a cathode of the optical coupler U1 and one end of the switch S1, the other end of the switch S1 is grounded via the resistor R9, and the second voltage source is also connected to the resistor R 4, the other end of the resistor R4 is connected to the collector of the optical coupler U1 and one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R8, one end of the capacitor C4, the base of the transistor Q2, and one end of the capacitor C5, the emitter of the optical coupler U1, the other end of the resistor R8, the other end of the capacitor C4, the other end of the capacitor C5, and the emitter of the transistor Q2 are grounded in common, the base of the transistor Q2 receives the first control signal, and the collector of the transistor Q2 is used to connect to the execution module (400).

5. The gas delay automatic control circuit for a plasma cutting machine according to claim 4, characterized in that: The execution module (400) comprises a solenoid valve, a diode D1, a MOS tube Q1, a resistor R1, a voltage regulator tube ZD1, a capacitor C2, and a diode D2; the second voltage source is connected to one end of the solenoid valve, the cathode of the diode D1, and one end of the resistor R1; the other end of the solenoid valve is connected to the anode of the diode D1 and the drain of the MOS tube Q1; the other end of the resistor R1 is connected to the cathode of the voltage regulator tube ZD1, the anode of the diode D2, the positive electrode of the capacitor C2, the anode of the voltage regulator tube ZD1, and the gate of the MOS tube Q1; the negative electrode of the capacitor C2 is grounded; the cathode of the diode D2 is connected to the collector of the transistor Q2, and is used to control the on and off of the solenoid valve.

6. The gas delay automatic control circuit for a plasma cutting machine according to claim 1, characterized in that: The capacitor C2 is an electrolytic capacitor.

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