JPH0768377A - Method and device for detecting working state of gas cutting - Google Patents

Abstract

PURPOSE:To obviate monitoring by visual observation confirmation by an operator and to carry out constitution as an unmanned operating device by detecting a working state according to a current value flowing through a flame formed between a steel sheet and a gas cutting torch. CONSTITUTION:When specified preheating is carried out, a cutting oxygen control mechanism 21 opens a solenoid value 11a to supply cutting oxygen gas to the torch 1, cutting is started for the steel sheet 2 and simultaneously, the cutting oxygen control mechanism 21 transmits a cutting oxygen control signal ON to a confirming means 25. Since a specified cutting current is passed through the flame 5, a measuring means 22 measures the current value and transmits it to a comparing means 24. The comparing means 24 compares the current value with the current value data from a storage part 23 and transmits a flame current signal to the confirming means 25. A recognizing means 25 transmits a present working state to an output part 26. The output part 26 displays cutting, etc., on a specified display part as necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting the ignition status of a cutting crater and the cutting status of the cutting crater in a gas cutting apparatus.

[0002]

2. Description of the Related Art Cutting a steel sheet using a gas cutting torch is widely performed. In particular, a so-called numerical control type gas cutting device that can automatically cut a figure including a curve from a large steel plate according to a preset program has been put into practical use, and is being used by shipbuilding manufacturers, bridge manufacturers, machine manufacturing manufacturers, etc. It is used.

When a steel sheet is cut using a gas cutting torch, a mistake in ignition of the cutting crater in the gas cutting device causes gas leakage of flammable gas, and defective cutting due to the cutting crater is a defective product. Therefore, it is essential to confirm the ignition status of the cutting crater and the cutting status by the cutting crater. Therefore, conventionally, such confirmation is generally performed by visual confirmation by the operator, and it is necessary for the operator to constantly monitor the gas cutting device.

In addition, as a technique of this kind, an infrared detection sensor is attached around the blow pipe to detect the ignition state,
There is one that detects the presence or absence of a flame by detecting infrared rays emitted from the flame. In addition, there is a method in which a photoelectric sensor is attached around the blow pipe to detect the cutting status, and the brightness at the burning point is detected to determine the cutting status.

[0005]

However, in the above-mentioned conventional technique, an infrared sensor or a photoelectric sensor mounted around the blow tube is set to face a predetermined position in the direction, and the presence or absence of a flame or the brightness of a cutting burning point is set. Since each of the sensors is detected, it is necessary to install the sensor in an extremely accurate direction and position with respect to the detection target point, and there is a problem that the sensor cannot be detected if the direction of the sensor deviates for some reason.

Further, particularly in the detection of the cutting burning point by the photoelectric sensor, when the cutting direction with respect to the steel plate changes, the target point to be detected moves to a position contrary to the photoelectric sensor, and the photoelectric sensor set in advance is set. Since it is not possible to detect the combustion point accurately because it detects a position where the detection position of is different from the combustion point, there are problems such as having to install multiple photoelectric sensors and selectively switch and detect. is there.

When the height of the torch changes with respect to the steel plate, the detection position of the photoelectric sensor deviates from the combustion point and cannot be accurately detected. Therefore, the detection position of the sensor follows the height of the torch. There is a problem that a device for controlling the

Therefore, the method for detecting the working condition in gas cutting according to the present invention is based on the current working condition of the steel plate by the gas cutting torch according to the current value flowing in the flame formed between the steel plate and the gas cutting torch. The aim is to provide a way to recognize.

Further, the apparatus for detecting a working state in gas cutting according to the present invention uses the above-mentioned method to produce a steel plate by the gas cutting torch according to a current value flowing in a flame formed between the steel plate and the gas cutting torch. It is an object of the present invention to provide a device for recognizing the current processing status of the.

[0010]

A method of detecting a working state in gas cutting according to the present invention is a method of applying a voltage between a steel plate and a gas cutting torch electrically insulated from the steel plate and applying a current. It is a method for detecting the processing status in gas cutting, which is characterized by measuring the value and recognizing the current processing status of the steel plate by the gas cutting torch according to the measured current value.

Further, the apparatus for detecting a processing state in gas cutting according to the present invention is a gas cutting torch electrically insulated from a steel plate to be cut, and a flow of preheating gas supplied to the gas cutting torch. ， A preheating control mechanism that controls the cutoff,
Flow of cutting oxygen gas supplied to the gas cutting torch,
Cutting oxygen control mechanism for controlling interruption, measuring means for energizing between the gas cutting torch and the steel plate and measuring the current value thereof, preset current value data during non-machining and current value during preheating A storage unit that stores data and current value data at the time of disconnection, a flame current corresponding to the measured current value by comparing the various current value data stored in the storage unit with the current value measured by the measuring unit. A comparison means for generating a signal, a flame current signal generated by the comparison means, and the presence or absence of control signals generated by the preheating control mechanism and the cutting oxygen control mechanism are compared to recognize the current machining situation and recognize the machining status signal. It is a device for detecting a processing state in gas cutting, which has a recognition means for generating

[0012]

[Function] Normally, the flame formed in the gas cutting torch is a high-temperature gas body, so some of the molecules in the gas body are ionized due to thermal energy, and the molecules are negatively charged with thermionic electrons. There are molecules with a charge of. Therefore, by applying a predetermined voltage between the electrically insulated torch and the steel plate, the electrons present in the flame and the molecules having a positive charge move in the flame. Then, the amount of the transferred electric charges is the electric current flowing in the flame, and the present inventor et al.
The experimental data shown in FIG. 5 was obtained using the circuit C shown in FIG.

In FIG. 4, the torch 1 is a good conductor composed of a blow tube 1a made of brass as a main material and a crater 1b made of copper as a main material (see FIG. 1). The steel plate 2 is also a good conductor. The torch 1 and the steel plate 2
When the power source 3 and the resistor 4 are electrically connected to each other in series and the flame 5 is not formed on the torch 1, the air layer between the torch 1 and the steel plate 2 serves as an insulator. No current flows.

When a flame 5 is formed on the torch 1 by using a predetermined means which will be described later, the flame 5 formed acts as a conductor as described above, so that the flame 5 formed on the torch 1 is applied to the steel plate 2. When contacted with, a circuit C composed of the power source 3, the resistor 4, the torch 1, the flame 5, and the steel plate 2 is formed, and the current I
Flows. Therefore, the current I can be measured by connecting an ammeter in series between a and b of the circuit C.

The table shown in FIG. 5 uses the above-mentioned circuit C to keep the power source 3 at a constant DC of 15 V, connects a DC ammeter between a and b of the circuit C, and uses a resistor 4 of 41 Ω to 1200 Ω. The current I was actually measured for three types of working conditions for the steel plate 2 by the gas cutting torch 1, namely preheating, cutting, and defective cutting. In addition, when not processing, that is, flame 5 on torch 1.
The value of the current flowing in the circuit C was 0 in the state in which no slab was formed.

During the preheating, the preheating oxygen gas and the fuel gas (for example, LPG, acetylene gas, propane gas, natural gas, etc.) are supplied to preheat the steel plate 2 with the flame 5 igniting the crater 1b. State. Further, “during cutting” refers to a state in which the cutting oxygen gas is supplied in addition to the preheating oxygen gas and the combustion gas to cut the steel sheet 2. Also,
When the cutting is not good, the preheating oxygen gas, the fuel gas, and the cutting cannot be maintained because the steady state for maintaining the cutting cannot be maintained due to a difference in the coating state of the surface of the steel plate 2 or the gas cutting device knocking for some reason. The state where the cutting is interrupted even though the oxygen gas for supply is supplied.

As is apparent from the table, the current I flowing during preheating and during disconnection failure shows the same value regardless of the value of the resistor 4, and the current I flowing during cutting is different in each case. It was found that the flow rate was 2 to 16 times as high as that during preheating or when cutting was poor.

Therefore, by appropriately selecting the value of the resistor 4, it is possible to set the ratio of the current I flowing in the flame at a desired ratio in accordance with the processing situation. That is, the resistance 4 is set to a predetermined value and the ratio of the current I is 0 in the non-machined state and in the ignition failure without flame, 5 in the preheating and cutting failure, and 10 in the cutting operation. After setting and measuring the current I in a certain machining situation, by comparing the ratios corresponding to the current values, it is possible to determine as one of the machining situations roughly classified into the three types. .

Further, by comparing the current I flowing through the flame 5 with and without the control signal generated by the preheating control mechanism and the cutting oxygen control mechanism, respectively, as shown in FIG. Medium, poor ignition, normal cutting, poor cutting,
It is possible to recognize six types of processing situations of misfire.
Therefore, the method for detecting the machining status of the present invention is possible by the above method.

Further, the processing state detecting apparatus of the present invention uses the above method to energize between the gas cutting torch and the steel sheet, measures the current value thereof, and then outputs the flame current signal corresponding to the current value. By the generated comparison means, it is possible to discriminate the processing status roughly classified into three types: non-processing or ignition failure, preheating or cutting failure, and cutting.

Further, a control signal generated from a preheating control mechanism for controlling the flow and interruption of the preheated oxygen gas and the preheating fuel gas supplied to the gas cutting torch, and the flow of the cut oxygen gas supplied to the gas cutting torch. , A control signal generated from a disconnection oxygen control mechanism for controlling interruption, and a flame current signal corresponding to the current value generated by the comparison means are compared by a recognition means to normally stop, during normal preheating, poor ignition, It is possible to recognize the six types of current processing statuses during normal cutting, poor cutting, and misfire.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a processing status detecting device for gas cutting according to the present invention will be specifically described with reference to the drawings, and its detecting method will be described. FIG. 1 shows the processing status detecting device of the present invention. A schematic side view illustrating the configuration of a gas cutting device that has,
2 is a block diagram of a control system for recognizing the machining status,
FIG. 3 is a recognition table for recognizing the processing status, and FIG. 4 is a basic circuit diagram for measuring the current value of the flame.

In the figure, the torch 1 is held by a holder 8 and attached to an elevating device 7 via an insulator 8a. Further, the torch 1 has a hose 9 for supplying a fuel gas such as LPG and acetylene gas, a hose 10 for supplying an oxygen gas for preheating, and a hose 11 for supplying an oxygen gas for cutting.
Are connected via corresponding insulating tubes 12, 13 and 14, respectively, and a cable 6 for energization and measurement is further connected.

The elevating device 7 to which the torch 1 is attached is attached to a carriage 16 which is traversably mounted on a frame 15 running along a rail (not shown). Further, the power source 3 and the resistor 4 which form the basic circuit C shown in FIG. 4 and the measuring means 22 which measures the current of the flame 5 which forms the control system block shown in FIG. 2 correspond to preset machining conditions. Storage unit 23 for storing various current value data, comparison unit 24 for comparing the measured value measured by the measuring unit 22 and the current value data stored in the storage unit 23, preheating control mechanism 20 and cutting oxygen control mechanism 21, the preheating Recognition means 2 for generating a machining status signal by comparing the control signal of the control mechanism 20 and the control signal of the cutting oxygen control mechanism 21 with the flame current signal generated by the comparison means 24.
5. The output unit 26 that outputs the information recognized according to the processing status signal or generates a predetermined control signal is incorporated in a control panel (not shown).

Further, the hose 9 for supplying the fuel gas for preheating, the hose 10 for supplying the oxygen gas for preheating, and the hose 11 for supplying the oxygen gas for cutting are respectively provided, and electromagnetic waves for respectively flowing and shutting off the respective gases are provided. The valves 9a, 10a and 11a are configured to be activated by respective drive signals generated by the preheat control mechanism 20 and the cutting oxygen control mechanism 21.

The preheating control mechanism 20 is a solenoid valve 9a, 10 provided on each of the hoses 9, 10 for fuel gas and oxygen gas for preheating.
At the same time as outputting a drive signal to a, it is turned on when both gases are flowing to the recognition means 25, and is turned off when both gases are cut off.
Is output as a preheat control signal.

Similarly, the cutting oxygen control mechanism 21 outputs a drive signal to the solenoid valve 11a provided on the cutting oxygen gas hose 11 and simultaneously turns on the recognition means 25 when the gas is flowing and when the gas is shut off. It is configured to output OFF as a cutting oxygen control signal.

The cutting oxygen control mechanism 21 is a preheating control mechanism.
Since it is configured to drive the solenoid valve 11a after confirming that 20 has driven the solenoid valves 9a and 10a, the cutting oxygen control signal is turned on only after confirming that the preheat control signal is turned on. It has a configuration such that

The current value data stored in advance in the storage unit 23 is such that the resistance 4 is set to a predetermined value, and the current I flowing through the flame 5 is the current value during non-machining and ignition failure, during normal preheating and disconnection. The current value at the time of failure and the current value at the time of normal disconnection are configured and set at a ratio of 0: 5: 10 to each other, and are transmitted to the comparison means 24 as necessary.

The measuring means 22 is configured to measure the current value of the flame 5 and transmit the measured data to the comparing means 24. As a method of measuring the current value, an ammeter may be connected between a and b of the circuit C shown in FIG. 4 to directly measure the current value, or the terminal voltage V1 generated across the resistor 4 may be measured to obtain the current value. It may be replaced.

The comparing means 24 compares the measurement data measured by the measuring means 22 with the current value data stored in the storage section 23, and when the ratio of the current values corresponds to 0, it is during non-machining or ignition failure. When the current value ratio is equal to 5, it is determined that the normal preheating is in progress or the disconnection is defective, and the current value ratio is 10
By deciding that the case corresponds to the normal cutting, the measured current value is roughly classified into the above-mentioned three kinds of processing situations and the flame current signal is transmitted to the recognition means 25.

The recognition means 25 outputs the O output from the preheating control mechanism 20.
Preheating control signal consisting of N and OFF, cutting oxygen control mechanism 21
The cutting oxygen control signal consisting of ON and OFF outputted by the above and the flame current signal consisting of 0, 5, 10 outputted from the comparing means 24 are respectively compared, and the present machining status signal is outputted according to the recognition table shown in FIG. Communicate to 26.

That is, when the flame current signal output by the comparison means 24 is 0 and the preheating control signal is OFF (the cutting oxygen control signal is OFF at this time), the machining status signal outputs "normal stop", and When the flame current signal is 0 and the preheat control signal is ON, the machining status signal outputs "ignition failure".

Next, when the flame current signal is 5 and the preheat control signal is ON, the machining status signal outputs "normal preheat". Next, when the flame current signal is 10 and the cutting oxygen control signal is ON (the preheating control signal is ON at this time), the processing status signal outputs "normal cutting", and the cutting oxygen control signal is ON. When the flame current signal becomes 5, "cutting failure" is output as a processing status signal. Similarly, when the cutting oxygen control signal is ON and the flame current signal becomes 0, "misfire" is output as the processing status signal.

The output unit 26 drives various safety devices in response to the above-mentioned processing status signals, informs or warns the operator, and performs various controls for returning the gas cutting device. It is possible to output a signal.

The means for actually recognizing the current processing status by using the processing status detection device configured as described above will be described in detail. For example, in the gas cutting apparatus E of FIG. 20 and cutting oxygen control mechanism 21 are OFF
The preheating control signal and the cutting oxygen control signal are both O
The FF is transmitted to the recognition means 25.

On the other hand, since the flame 5 is not generated, the flowing current is 0, and the current value measured by the measuring means 22 and the current value data stored in the storage section 23 are compared by the comparing means 24 to compare the comparing means. 24 is a means for recognizing the flame current signal 0
Communicate to 25. At this time, the recognition means 25 according to the recognition table of FIG.
Determines that the current machining status is "normal stop" and transmits it to the output unit 26. The output unit 26 displays a stop or the like on a predetermined display unit as needed.

Next, the preheat control mechanism 20 operates the solenoid valves 9a and 10a.
Is opened to ignite the crater 1b to start preheating the steel plate 2, and at the same time, the preheating control mechanism 20 transmits a preheating control signal ON to the recognition means 25. (At this time, the cutting oxygen control mechanism 21 turns off the cutting oxygen control signal with the solenoid valve 11a closed.
Is transmitted to the recognition means 25. At this time, the flame 5 is formed and a predetermined preheating current flows, so that the measuring means 22 measures the current value and transmits it to the comparing means 24.

The comparison means 24 compares the current value with the current value data from the storage section 23 and transmits the flame current signal 5 to the recognition means 25. At this time, the recognizing means 25 judges the current machining status as "normal preheating" according to the recognition table of FIG.
Communicate to. The output unit 26 displays preheat and the like on a predetermined display unit as needed.

At this time, if the ignition to the crater 1b is misfiring, the preheat control mechanism 20 transmits the preheat control signal ON to the recognition means 25, but the flame 5 is not formed, so the current value is 0. Therefore, similarly, the comparing means 24 transmits the flame current signal 0 to the recognizing means 25. Therefore, the recognizing means 25 determines the current machining status as "ignition failure" according to the recognition table and transmits it to the output unit 26. The output unit 26 displays an ignition failure or the like on a predetermined display unit as necessary, and controls the preheat control mechanism 20 as necessary to perform re-ignition or the like.

Next, when a predetermined preheating is performed, the cutting oxygen control mechanism 21 opens the solenoid valve 11a to supply the cutting oxygen gas to the torch 1.
The cutting oxygen control mechanism 21 transmits the cutting oxygen control signal ON to the recognition means 25 at the same time when the cutting of the steel plate 2 is started. (At this time, the preheat control mechanism 20 outputs the preheat control signal O
This is a state in which N is transmitted to the recognition means 25. ) Then, since a predetermined cutting current flows through the flame 5, the measuring means 22 measures the current value and transmits it to the comparing means 24.

The comparison means 24 compares the current value with the current value data from the storage section 23 and transmits the flame current signal 10 to the recognition means 25. At this time, the recognizing means 25 judges the current machining status as "normal cutting" according to the recognition table of FIG.
Communicate to 26. The output unit 26 displays disconnection or the like on a predetermined display unit as needed.

At this time, if the steady state required for cutting cannot be maintained for some reason and the cutting is interrupted, the cutting oxygen control mechanism 21 transmits the cutting oxygen control signal ON to the recognition means 25, but the flame 5 cuts. Attenuates to a defective state, and at the same time the current value also decreases. At this time, the comparison means 24 compares the current value measured by the measurement means 22 with the current value data from the storage section 23 and transmits the flame current signal 5 to the recognition means 25.

The recognizing means 25 judges the current machining status as "cutting failure" according to the recognition table and transmits it to the output section 26.
The output unit 26 can display a defective cutting or the like on a predetermined display unit as necessary, and can control the cutting device E to stop or re-cut as necessary.

In the above case, if the misfire occurs due to some reason, the cutting oxygen control mechanism 21 turns on the cutting oxygen control signal.
Is transmitted to the recognition means 25 (at this time, the preheating control mechanism
20 is a state in which the preheat control signal ON is transmitted to the recognition means 25. ) The flame 5 falls into a misfire state, and at the same time, the current value becomes 0, and the flame current signal 0 is transmitted from the comparison means 24 to the recognition means 25.

The recognizing means 25 judges the current machining status as "misfire" according to the recognition table and transmits it to the output section 26. The output unit 26 displays a misfire or the like on a predetermined display unit as necessary, and controls the cutting device E to stop and restore the device as needed to perform re-cutting after re-preheating. Is.

[0047]

As described above, the method and apparatus for detecting the processing status in gas cutting according to the present invention have the above-described structure and operation, and therefore the processing status can be judged by directly measuring the current flowing through the flame. Therefore, it is possible to configure an unmanned operation device, which does not require monitoring by visual confirmation by an operator as in the past.

In addition, as in the conventional case where the infrared sensor or the photoelectric sensor is attached to the blow tube for indirect measurement, the direction of the sensor is misaligned, the cutting direction is changed, or the torch height is increased. The problem of being undetectable due to changes can also be solved.

[Brief description of drawings]

FIG. 1 is a schematic side view illustrating the configuration of a gas cutting device having a processing status detection device of the present invention.

FIG. 2 is a block diagram of a control system for recognizing a processing status.

FIG. 3 is a recognition table for recognizing a processing status.

FIG. 4 is a basic circuit diagram for measuring a current value of a flame.

FIG. 5 is an experimental data table explaining the operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Torch 1a ... Blowing pipe 1b ... Tractor 2 ... Steel plate 3 ... Power source 4 ... Resistance 5 ... Fire flame 6 ... Cable 7 ... Elevating device 8 ... Holder 8a ... Insulator 9,10,11
... Gas hoses 9a, 10a, 11a ... Solenoid valves 12, 13, 1
4 ... Insulation pipe 15 ... Frame 16 ... Carriage 20 ... Preheating control mechanism 21 ... Cutting oxygen control mechanism 22 ... Measuring means 23 ... Storage part 24 ... Comparison means 25 ... Recognition means 26 ... Output part E ... Gas cutting device

Claims (2)

[Claims] 1. A current applied to a steel sheet by a gas cutting torch according to the measured current value by applying a voltage between the steel sheet and a gas cutting torch electrically insulated from the steel sheet. A method for detecting the processing status in gas cutting, which is characterized by recognizing the processing status. 2. A gas cutting torch electrically insulated from a steel plate to be cut, a preheating control mechanism for controlling the flow and interruption of a preheating gas supplied to the gas cutting torch, and a gas cutting torch. A cutting oxygen control mechanism for controlling the flow and interruption of the cutting oxygen gas, a measuring means for energizing between the gas cutting torch and the steel plate and measuring the current value thereof, and a preset non-working current A storage unit that stores the value data, the current value data at the time of preheating, and the current value data at the time of cutting, and the measurement by comparing the various current value data stored in the storage unit with the current value measured by the measuring unit. Comparing means for generating a flame current signal corresponding to the current value, the presence or absence of the control signal generated by the preheating control mechanism and the cutting oxygen control mechanism and the flame current signal generated by the comparison means. And a processing unit for recognizing the current processing status and generating a processing status signal.