JPH08186304A - Gas laser apparatus - Google Patents

Abstract

PURPOSE: To provide an apparatus by which a laser gas is injected until a gas pressure at the inside of a gas circulation system reaches atmospheric pressure while it is being confirmed that the laser gas is supplied from the outside when an operation is suspended. CONSTITUTION: A gas laser apparatus is provided with a solenoid valve which injects a laser gas into the inside of a gas circulation system, with a first pressure switch 4 which detects that a gas pressure at the inside of the gas circulation system has reached atmospheric pressure, with a second pressure switch 5 which detects that the laser gas is supplied from the outside and with an abnormality display device 19 which detects and displays the abnormality of a laser-gas supply source on the basis of the state of the first pressure switch and the second pressure switch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device for injecting a laser gas until the gas pressure inside the gas circulation system reaches atmospheric pressure when the device is stopped.

[0002]

2. Description of the Related Art In a gas laser device, the inside of the gas circulation system is operated at a gas pressure lower than the atmospheric pressure (atmospheric pressure) of the outside, so that water and dust easily enter due to the pressure difference from the outside. . Therefore, when the gas laser device is not used for a long period of time, the gas pressure inside the gas circulation system is made equal to the external atmospheric pressure (atmospheric pressure) to prevent the intrusion of water and dust. As a method therefor, there has been a device having a configuration as shown in FIGS. 1 and 2.

FIG. 1 is a diagram showing an example of a conventional apparatus. In FIG. 1, 1 is a discharge tube, 2 is a sequence controller, 5 is a pressure switch, 6 is a laser gas cylinder, and 7 is a forced circulation of laser gas. Blower, 8 is a vacuum pump,
9 is a circulation path, 10 and 11 are solenoid valves, 14 is a manual on-off valve, 15 is a desiccant chamber, 16 is an output mirror, 17 is a reflecting mirror,
20 and 21 are gas regulators.

In FIG. 1, an output mirror 16 and a reflecting mirror 17 are arranged so as to sandwich the discharge tube 1 to form an optical resonator. The laser gas is circulated by the blower 7 through the circulation path 9 and forms a gas flow in the discharge tube 1. The first solenoid valve 1 is provided in each of the branch paths branched from the circulation path 9.
0, a second solenoid valve 11 and a manual on-off valve 14 are provided. The first solenoid valve 10 is connected to the laser gas cylinder 6, and the second solenoid valve 11 is connected to the vacuum pump 8. The gas pressure at the outlet of the laser gas cylinder 6 is adjusted by the gas regulator 20, and the gas pressure at the inlet of the first solenoid valve 10 is adjusted by the gas regulator 2.
It is regulated by 1. A desiccant chamber 15 is provided between the opening / closing valve 14 and the outside. Each solenoid valve 1
The operations of 0, 11, the blower 7 and the vacuum pump 8 are controlled by the sequence controller 2. The pressure switch 5 detects that the laser gas is being supplied from the laser gas cylinder 6 connected to the outside, and its output signal is connected to the sequence controller 2.

In the above structure, the first electromagnetic valve 10 and the second electromagnetic valve 11 are open and the open / close valve 14 is closed during the operation of the gas laser device. Fresh laser gas is supplied from the laser gas cylinder 6 through the first solenoid valve 10 to the circulation path 9, is sent out from the circulation path to the discharge tube 1 by the blower 7, and passes through the discharge tube 1 and the circulation path 9 to the blower 7
Return to and circulate. Further, the laser gas deteriorated due to circulation and discharge is discharged to the outside from the circulation path 9 through the second electromagnetic valve 11 by the vacuum pump 8.

When the gas laser device is stopped for a long period of time,
The blower 7 and the vacuum pump 8 are stopped, and the first solenoid valve 1
0 and the second solenoid valve 11 are closed, the opening / closing valve 14 is opened, and the external air is passed through the desiccant in the desiccant chamber 15 to remove water contained in the air, and then circulate. When the gas is injected into the passage 9 and the gas pressure inside the gas circulation system becomes equal to the atmospheric pressure and the inflow of air stops, the on-off valve 1
Close 4

FIG. 2 is a diagram showing another example of a conventional device. In FIG. 2, 3 and 12 are solenoid valves, and 13 is opened when the pressure on the inlet side and the pressure on the outlet side become equal. A constant pressure valve that outputs an open state as a signal, 22 is a gas regulator, and other parts have the same functions as those in FIG.

In FIG. 1, an output mirror 16 and a reflecting mirror 17 are arranged so as to sandwich the discharge tube 1 and form an optical resonator. The laser gas is circulated by the blower 7 through the circulation path 9 and forms a flow in the discharge tube 1. Circuit 9
The first branch of the solenoid valve 10 and the second branch of the second branch path
Solenoid valve 11, third solenoid valve 3 and fourth solenoid valve 12
Is provided. The first solenoid valve 10 and the third solenoid valve 3 are connected to the laser gas cylinder 6, and the second solenoid valve 11 is connected to the vacuum pump 8. The gas pressure at the exit of the laser gas cylinder 6 is adjusted by the gas regulator 20, the gas pressure at the entrance of the first solenoid valve 10 is adjusted by the gas regulator 21, and the gas pressure at the entrance of the third solenoid valve 3 is adjusted by the gas regulator 22. Has been done. Further, a constant pressure valve 13 that automatically opens when the gas pressure inside the gas circulation system reaches atmospheric pressure is provided between the fourth solenoid valve 12 and the outside. Each solenoid valve 10, 11, 3,
The operations of 12, the blower 7, and the vacuum pump 8 are controlled by the sequence controller 2. The output signal of the second pressure switch 5 that detects that the laser gas is being supplied from the laser gas cylinder 6 connected to the outside and the output signal of the operating state of the constant pressure valve 13 are connected to the sequence control device 2. There is.

In the above structure, the first solenoid valve 10 and the second solenoid valve 11 are open, and the third solenoid valve 3 and the fourth solenoid valve 12 are closed during the operation of the gas laser device. Fresh laser gas is supplied from the laser gas cylinder 6 through the first electromagnetic valve 10 to the circulation path 9, is sent from the circulation path 9 to the discharge tube 1 by the blower 7, and is passed through the discharge tube 1 and the circulation path 9 to the blower 7 Return to and circulate.
Further, the laser gas deteriorated due to circulation and discharge is discharged to the outside from the circulation path 9 through the second electromagnetic valve 11 by the vacuum pump 8.

When the gas laser device is stopped, that is, the blower 7 and the vacuum pump 8 are stopped, and the first solenoid valve 10 and the second solenoid valve 11 are closed, the third solenoid valve 3 is opened and the gas is shut off. Laser gas is injected into the circulation system to
Open the solenoid valve 12 of. When the gas pressure inside the gas circulation system reaches the atmospheric pressure, the constant pressure valve 13 is automatically opened, and when this is detected, the third solenoid valve 3 and the fourth solenoid valve 12 are closed.

[0011]

However, in the case of the method shown in FIG. 1, when a large amount of air is suddenly introduced, there is a possibility that water may not be sufficiently removed or that the on-off valve may be left unclosed due to manual operation. . In addition, when the desiccant deteriorates and the moisture absorption capacity deteriorates, it is necessary to replace the desiccant, which requires a cost and labor. Figure 2
In the case of the method (1), a large amount of gas flows when the solenoid valve 3 is opened, which causes the gas pressure at the inlet to drop, and the pressure switch 5 outputs a pressure drop signal. Since this pressure drop signal is generated even when the internal pressure of the cylinder is insufficient, the two cannot be distinguished from each other, and it is necessary to provide the sequence control device 2 with a complicated determination function.

That is, the pressure detected by the pressure switch 5 varies depending on the residual pressure of the gas cylinder, the capacity of the gas regulator 20 for adjusting the original pressure of the laser gas, the pipe length and the pipe diameter between the gas cylinder and the gas laser device, and the like. Therefore, for example, when the gas regulator 20 has a small capacity, if the laser gas is rapidly injected into the gas circulation system,
The supply of gas from the cylinder cannot catch up, and the gas pressure at the outlet of the gas regulator 20 temporarily drops. As a result, the pressure switch 5 may fall below the set value.
In this case, just observing the output of the pressure switch indicates whether the gas pressure has dropped due to the injection of laser gas into the gas circulation system, or the gas pressure has dropped due to some abnormality in the laser gas supply source or supply path. Therefore, it is impossible to judge whether the gas pressure drop phenomenon is normal or abnormal.

On the other hand, if the injection amount of the laser gas is reduced to such an extent that the pressure switch 5 does not detect the pressure drop, it takes a long time to inject the laser gas. Further, when the output of the pressure switch is ignored during the injection of the laser gas, even if an abnormality occurs in the gas pressure of the laser gas supplied from the outside, the abnormality cannot be detected.

The present invention has been made in view of the above problems, and an object thereof is to be able to inject a laser gas into the gas circulation system in a short time regardless of the laser gas supply capacity from the outside and to inject the laser gas during the injection of the laser gas. Provided is a gas laser device that detects when the gas pressure of the laser gas supplied from the device is lowered due to an abnormality in the laser gas supply source or the supply path, stops the injection of the laser gas, and warns the occurrence of the abnormality. Is.

[0015]

In order to achieve the above object, the present invention provides a gas laser device for oscillating a laser while circulating a laser gas, in which a laser gas is injected into a gas circulation system consisting of a discharge tube and a circulation path. Valve, a first pressure switch that operates when the gas pressure inside the gas circulation system becomes atmospheric pressure, a second pressure switch that detects the pressure in the laser gas supply side piping, and a solenoid valve when the device is stopped. Is opened for a certain period of time to inject the laser gas into the gas circulation system, and when the solenoid valve is closed due to the end of the time period of the timed circuit, the second pressure switch causes the pressure of the gas supply side pipe to reach a predetermined value within a certain period of time. When it is detected that the above has been reached, the time limit circuit is activated again, and if it does not reach the predetermined value or more after the elapse of a certain time, it is judged as abnormal and the first
The present invention proposes a gas laser device equipped with a sequence control circuit that suspends the operation of the timed circuit when the pressure switch of FIG.

[0016]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 3 is a diagram showing an embodiment of the device of the present invention, in which 1 is a discharge tube, 2 is a sequence controller, 4 and 5 are pressure switches, 6 is a laser gas cylinder, 7 is a blower, and 8 is a vacuum. Pump, 9 is a circulation path, 3, 1
0 and 11 are solenoid valves, 16 is an output mirror, 17 is a reflector,
Reference numeral 19 is an abnormality indicator, and 20, 21 and 22 are gas regulators.

In FIG. 1, an output mirror 16 and a reflecting mirror 17 are arranged so as to sandwich the discharge tube 1 to form an optical resonator. The laser gas is circulated by the blower 7 through the circulation path 9 and forms a gas flow in the discharge tube 1. The first solenoid valve 1 is provided in each of the branch paths branched from the circulation path 9.
0, a second solenoid valve 11 and a third solenoid valve 3 are provided. The first solenoid valve 10 and the third solenoid valve 3 are connected to the laser gas cylinder 6 and the second solenoid valve 11 is connected.
Is connected to a vacuum pump 8. Laser gas cylinder 6
The gas pressure at the outlet of the gas regulator 20,
The gas pressure at the inlet of the first solenoid valve 10 is adjusted by the gas regulator 21, and the gas pressure at the inlet of the third solenoid valve 3 is adjusted by the gas regulator 22. The operation of each solenoid valve 3, 10, 11, the blower 7, and the vacuum pump 8 and the display output of the abnormality indicator 19 are controlled by the sequence controller 2. The first pressure switch 4 detects the gas pressure inside the gas circulation system consisting of the discharge tube 1 and the circulation path 9, generates an output signal when the gas pressure inside reaches the atmospheric pressure, and outputs the second pressure switch. Reference numeral 5 detects the laser gas pressure supplied from the laser gas cylinder 6 connected to the outside, and the output signals thereof are connected to the sequence controller 2.

FIG. 4 is a time chart when the laser gas is injected into the gas circulation system in the embodiment of FIG. 3, and FIG. 5 is a flow chart when the laser gas is injected into the gas circulation system in the embodiment of FIG. FIG. 6 is a time chart when an abnormality occurs when the laser gas is injected into the gas circulation system in the embodiment of FIG.

In the embodiment of FIG. 3, the case where the laser gas is injected into the gas circulation system to bring it to atmospheric pressure is shown in FIG.
This will be described with reference to FIGS. 5 and 6. The gas laser device is stopped, that is, the blower 7 and the vacuum pump 8 are stopped,
In the state where the first solenoid valve 10 and the second solenoid valve 11 are closed, first, it is confirmed by the first pressure switch 4 whether the inside of the gas circulation system is already at the atmospheric pressure before the laser gas is injected, and the outside is checked. Check whether the laser gas is being supplied from the second
Check with the pressure switch 5 (Step 2 in FIG. 5,
3). Next, laser gas is injected until the third solenoid valve 3 is opened and the first pressure switch 4 is turned on, or until T1 seconds have elapsed after the third solenoid valve 3 was opened, and the third solenoid valve 3 The valve 3 is closed (steps 4 to 7 in FIG. 5). The injection time T1 of the laser gas in this case is such that the output of the gas laser device is not affected even if a gas other than the laser gas is mixed into the gas circulation system due to an abnormality, that is, the laser gas is injected into the gas circulation system. It is preferable to set the time to about 10% of the time required to reach atmospheric pressure.

Here, when the external laser gas supply capacity is low, the gas pressure of the laser gas supplied decreases when the third solenoid valve 3 is opened, and the second pressure switch 5 is OF
It becomes F (timing “A” in FIG. 4). However, even in this case, if the third solenoid valve 3 is closed T1 seconds after opening the third solenoid valve 3 and the laser gas is normally supplied, by the time T2 seconds after the abnormality detection time limit, The gas pressure of the supplied laser gas is restored to the original level, and the second pressure switch 5 is turned on (timing "b" in FIG. 4). The abnormality detection time limit T2 in this case is the second pressure switch when the gas pressure of the supplied laser gas is restored to the original level after the third solenoid valve 3 is closed when the laser gas is normally supplied. It suffices that the time is longer than the time required for the switch 5 to be turned on, and for example, it may be set to about twice the time.

As described above, even if the second pressure switch 5 is once turned off by opening the third solenoid valve 3, the second pressure switch 5 is turned on when the third solenoid valve 3 is closed. In this case, it is considered that the laser gas is normally supplied, and the third electromagnetic valve 3 is opened again to inject the gas. This control is repeated until the gas pressure inside the gas circulation system reaches the atmospheric pressure, that is, until the first pressure switch 4 is turned on (timing "C" in FIG. 4). (Steps 3 to 8 in FIG. 5)

If the laser gas is no longer supplied from the outside for some reason, such as when the residual pressure of the laser gas cylinder becomes low or the gas pipe is damaged during the injection of the laser gas, the third solenoid valve 3 is turned on. When opened, the gas pressure of the supplied laser gas drops and the second pressure switch 5
Is turned off (timing “d” in FIG. 6), and even if the third solenoid valve 3 is closed thereafter, the gas pressure of the laser gas supplied by the time T2 seconds after the abnormality detection time limit is not recovered. The second pressure switch 5 remains OFF. In this way, even if the third solenoid valve 3 is closed after the second pressure switch 5 is turned off by opening the third solenoid valve 3, the gas supply side pressure does not rise and the second pressure If the switch 5 remains off, it is considered that some abnormality has occurred in the supply of the laser gas from the outside, and the abnormality signal is output to the abnormality indicator 19 with the third solenoid valve 3 closed (timing in FIG. 6). "E", steps 8 to 1 in FIG.
0).

In the above-mentioned embodiment, the case where the gas injected to bring the gas pressure inside the gas circulation system to the atmospheric pressure is the laser gas has been described, but the present invention is not limited to this and other dry gas is used. The same applies to, for example, those containing dry air, nitrogen gas and the like.

Since the second pressure switch 5 can also serve as a pressure switch for detecting the supply of the laser gas during the normal operation, it is not necessary to provide a new pressure switch.

[0025]

As described above, according to the present invention, when an abnormality occurs in the laser gas supply capacity from the outside, the abnormality can be detected promptly and accurately, and the gas is used for detecting the abnormality. Since it is not necessary to reduce the supply amount of the gas, the gas pressure inside the gas circulation system can be brought to atmospheric pressure in a short time.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a conventional device.

FIG. 2 is a diagram showing an example of another conventional device.

FIG. 3 is a diagram showing an embodiment of the present invention.

FIG. 4 is a time chart when the laser gas is injected into the gas circulation system in the embodiment of FIG.

5 is a flowchart for injecting a laser gas into the gas circulation system in the embodiment of FIG.

FIG. 6 is a time chart when an abnormality occurs when a laser gas is injected into the gas circulation system in the embodiment of FIG.

[Explanation of symbols]

 1 Discharge Tube 2 Sequence Control Device 3 Third Solenoid Valve 4 First Pressure Switch 5 Second Pressure Switch 6 Laser Gas Cylinder 7 Blower 8 Vacuum Pump 9 Circulation Path 10 First Solenoid Valve 11 Second Solenoid Valve 12 Second 4 Solenoid valve 13 Constant pressure valve 14 Manual on-off valve 15 Desiccant chamber 16 Output mirror 17 Reflector 19 Abnormality indicator 20, 21, 22 Gas regulator

Claims (1)

[Claims] 1. A gas laser device for performing laser oscillation while circulating a laser gas, wherein a solenoid valve for injecting a laser gas into a gas circulation system consisting of a discharge tube and a circulation path, and a gas pressure inside the gas circulation system are atmospheric pressure. A first pressure switch that operates when the temperature of the laser gas reaches a second pressure switch that detects the pressure of the laser gas supply side pipe, and the electromagnetic valve is opened for a certain period of time when the apparatus is stopped to allow the laser gas to flow in the gas circulation system. And a second circuit for detecting that the pressure in the gas supply side pipe has exceeded a predetermined value within a certain time when the solenoid valve is closed due to the end of the time circuit. When the time limit circuit is activated again, if it does not reach the predetermined value or more after a certain period of time, it is judged as abnormal and when the first pressure switch operates. A gas laser device comprising a sequence control circuit for stopping the operation of the time circuit.