JPS6354792A - Gas supplying/discharging device for gas laser oscillator - Google Patents

Abstract

PURPOSE:To so adjust gas discharging as to reduce a pressure variation in a laser gas vessel by branching a gas discharge passage to two passages, and setting the discharge flow rates of the passages to the values near the injecting flow rate. CONSTITUTION:A conduit from a pipe 26 to a vacuum pump 30 disposed at the rear stream side of a discharge passage is branched to two passages 44, 45. The opening of a valve 41 is so set by a manual adjustment that the discharge flow rate of the laser gas passing one passage 44 is slightly more than the injecting gas flow rate from a gas cylinder 21 and the discharge flow rate of the laser gas passing the other passage 45 is slightly less than the injecting gas flow rate from the cylinder 21. Solenoid valves 42, 43 are so opened or closed as to alternately switch to selectively open the passages 44, 45 by the pressure variation in a vessel 6 to control the laser gas pressure in the vessel 6 in a predetermined range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for continuously supplying and exhausting laser gas into a laser gas container of a continuous gas exchange type gas laser oscillator.

[Conventional technology] There are two broad types of gas laser oscillators.

One of these is the "laser gas sealed type", which is mainly used for large-capacity products.When a portion of the laser gas is sealed in the laser gas container, the gas is released during laser operation. Gas is not supplied or exhausted, but the entire amount of gas is replaced after a predetermined period of use.

Another type is the "continuous gas exchange type," which exchanges gas by continuously supplying and exhausting a portion of the laser gas in the laser gas container during laser operation.

It is equipped with a gas supply and exhaust system to exchange part of the gas.

The reason why the laser gas in the container is replaced in this manner is that the components of the filled laser gas change as the laser output increases.

Of the above two types, the conventional technology of the latter type of gas laser oscillator will be explained with reference to Fig. 3. In the figure, (1) and (2) are arranged opposite to each other,
), (4) is a total reflection mirror, (5) is a partial reflection mirror placed opposite to total reflection mirror (4), and (6) is a laser gas container, inside which a laser oscillation is carried out. The container (6) is filled with a laser gas for the purpose of the laser treatment, and the gas is circulated in the container (6) as shown by the arrow by a blower (7).(8)
is a gas cooler that cools the laser gas excited and heated in the discharge space (9) by glow discharge caused by the electrodes (1) and (2). (10) is a beam laser,
In this beam laser ('to), the laser gas gains energy and is excited by the discharge in the discharge space (9), causing laser oscillation, and the laser is reflected by fi (4), (5).
Each time it moves back and forth between the two, discharge energy is obtained and reflected repeatedly, and then it passes through a partial reflecting mirror (5) and is emitted to the outside for a predetermined purpose.

The gas container (6) of the gas laser oscillator (11) with such a configuration
) A gas supply/exhaust device as shown in the figure is provided in order to continuously exchange a part of the laser gas in the gas cylinder (21) during laser output. (22), (23) are injected in fixed amounts into the container (6) via the flowmeter (24) and pipe (25). In this case, the predetermined injection flow rate is set by manually adjusting the opening degree of the valve (23), while the laser gas in the container (6) is discharged through a pipe that communicates the gas with the container (6). (26), the solenoid valve (29) is opened and closed based on the reference pressure H and L signals from the pressure gauge (2nd) which indicates the pressure inside the container (6) through the valve (27). There is. That is, when the pressure inside the container (6) increases and reaches the upper limit reference pressure H, the solenoid valve (29) becomes "open" due to the output signal, and the "open" state continues and the inside of the container (6) When the pressure decreases to the lower limit reference pressure, the output signal causes the solenoid valve (29) to close. In this case, the predetermined discharge flow rate is set by the valve ( This is done by manually adjusting the opening degree of step 27), but it needs to be set considerably larger than the injection flow rate. This is because if the gas exhaust flow rate is set close to the gas injection flow rate, the pressure range to be controlled will become unstable due to dust clogging in the valve (27), etc., and changes over time caused by seasonal temperature changes, etc. If the gas exhaust flow rate becomes smaller than the gas injection flow rate, the laser gas pressure inside the container (6) will continue to rise even if the electromagnetic 4r (2a) is in the "open" state, resulting in a dangerous situation. This is for the purpose of In addition, (30) is a vacuum pump that is constantly operating even during gas supply and exhaust, and (31) is a T
This is a bypass circuit for the L solenoid valve 29), and normally the valve (3
2) is “closed”.

[Problems to be Solved by the Invention] Normally, the pressure of the laser gas in the container (6) is several tens of Torr.
rl (e.g. 50 Torr) c7) Note that this is often the case, but since the laser oscillation efficiency changes with fluctuations in the laser gas pressure, if the fluctuation range of the internal pressure of the container (6) is large (e.g. 50 Torr ± 5 Torr), the laser Since the fluctuation in output also becomes large, it is necessary to adjust the pressure so as to reduce the range of fluctuation.

However, when adjusting the pressure with a small fluctuation range (for example, 50 Torr ± 1 Torr) using the gas supply and exhaust device of the conventional gas laser oscillator as described above, the valve (2
7) It takes time to finely adjust the opening, and moreover, the exhaust gas flow rate tends to change over time. Also, it is desirable that the solenoid valve (29) opens and closes less frequently (for example, once/1 time).
(approximately 0 seconds), and in the conventional device, the frequency of opening and closing is very high (for example, 1 to 3 times/second), and therefore the life of the solenoid valve (29) is shortened, and this solenoid valve (29) has to be operated frequently. The problem was that it had to be replaced. In particular, the above-mentioned problem becomes serious when the volume of the container (6) is small or when the gas injection flow rate is large.

Furthermore, if the pressure of the laser gas in the container (6) increases too much, the load on the blower (7) disposed in the container (6) will increase, causing seizure of the bearing of the blower (7) and damage to the power supply. There was a problem in that a failure occurred and the blower (7) could no longer be rotated in the normal direction.

This invention was made to solve these problems, and it is possible to perform gas discharge 3J to reduce pressure fluctuations in the laser gas container, and to reduce the frequency of opening and closing of the solenoid valve. The object of the present invention is to obtain a gas supply/exhaust device for a gas laser oscillator that can improve the service life.

[Means for solving the problem] A gas supply and exhaust device for a gas laser oscillator according to the present invention has the following features:
A laser gas container is filled with a laser gas for laser oscillation, and the laser gas is continuously supplied and exhausted into the container for gas exchange.The exhaust path is branched into two, and one branch path is The exhaust flow rate is set to be slightly higher than the injection gas flow rate, and the other branch route is set to a discharge flow rate slightly lower than the injection gas flow rate, and a switch is installed on the exhaust route, and this switch One branch path is selectively opened and circulated by an upper limit setting pressure signal from a pressure gauge that detects the internal pressure, and the other branch path is selectively opened by a lower limit setting pressure signal from the pressure gauge. It is.

[Operation] In the present invention, since the gas exhaust route is branched into two routes, it is possible to set the exhaust flow rate through each route to a value close to the injection flow rate.

[Embodiment] Based on an embodiment of the present invention shown in FIG. 1, the features of the present invention will be mainly explained below, with the same or equivalent parts as those in the prior art being given the same reference numerals. FIG. 1 is an explanatory diagram of the apparatus of this embodiment, and as shown in the figure, one feature of the present invention is the means for discharging the laser gas in the laser gas container (6).

That is, a gas exhaust pipe (
26) is installed, and in this exhaust route, a pipe (26) and a vacuum pump (30) arranged on the downstream side are installed.
The route between the two branches is divided into two routes (44) and (45). One branch route (44) has a valve (40) and a switch (42), and the other branch route (45) has a valve (41).
and a switch (43) are respectively provided. In this embodiment, a case is shown in which electromagnetic valves are used as the opening/closing Ws (42) and (43), respectively. In addition, a bypass circuit (31) equipped with equipment for injecting gas into the container (6) and a valve (32) is provided.
), and a pressure gauge (28) similar to that shown in FIG. 3 is provided.

Next, the operation of the above-described embodiment configured as above will be explained. First, the solenoid valve (43) is "closed" and the solenoid valve (43) is "closed".
2) is in the "open" state, one branch route (44)
The exhaust flow rate of the laser gas passing through the cylinder (21
) The zero-order solenoid valve (42) is set by manually adjusting the opening degree of the valve (40) so that a predetermined flow i (Q+) is slightly larger than the injection gas flow ff1 (Q) from the When the solenoid valve (43) is in the “closed” state and the solenoid valve (43) is in the “open” state, the other branch path (
The opening degree of the valve (41) is manually adjusted so that the discharge flow rate of the laser gas passing through the cylinder (45) is a predetermined flow rate (Q2) that is slightly smaller than the injection gas flow rate (Q) from the cylinder (21). Set.

However, at first, both solenoid valves (42) and (43) were "closed".
When the laser gas is injected from the cylinder (21) into the container (6) in a constant amount (Q) at a time, the container (
6) rises and reaches the upper limit reference pressure H, the solenoid valve (4) is activated by the upper limit setting pressure signal from the pressure gauge (28).
2) becomes “open”, then route (44) becomes (Q+
) is discharged. Here, the discharge flow rate (Q+
) is slightly higher than the injection flow rate (Q), so the container (8)
The internal pressure slowly decreases and eventually reaches the lower limit reference pressure. Then, the solenoid valve (42) is "closed" by the lower limit setting pressure signal from the pressure gauge (28), and the solenoid valve (43) is closed.
) becomes "open", then the set discharge flow rate (Q2) of route (45) is slightly smaller than the injection flow rate (Q), so
The pressure inside the container (6) increases slowly and eventually reaches the upper limit reference pressure H, and the solenoid valves (42) and (43) are switched by the upper limit setting pressure signal from the pressure gauge (28). Thereafter, the above switching is repeated due to pressure fluctuations within the container (6). In this way, by alternately switching the two branch paths (44) and (45) to selectively open and circulate the two branch paths (44) and (45) using the solenoid valves (42) and (43),
The laser gas pressure within the container (6) is controlled within a certain range.

FIG. 2 is an explanatory diagram showing another example device, and shows two branch paths (44) in this example.

(45) to selectively open and circulate the switch (5
0) shows the case where one three-way solenoid valve (50) is used instead of the two solenoid valves used in the above embodiment. That is, the branch paths (44) and (45) can be switched by operating the three-way solenoid valve (50) based on the -upper and lower constant pressure signals from the pressure gauge (28).

Therefore, in each of the above embodiments, the route (44).

(45) In both cases, the container (
6) Since the gas within is constantly exhausted, the pressure control width (
For example, even if the temperature is 50 Torr±ITorr), the number of openings and closings of the solenoid valves (42), (43) or the three-way TL solenoid valve 50) will be reduced (for example, the number of openings and closings can be reduced to about 710 seconds each time). , the life of the solenoid valve or three-way solenoid is extended, and the failure of the switch is reduced. In addition, since the range of gas pressure fluctuation in the container (6) can be reduced, it is possible to prevent a decrease in laser oscillation efficiency, and the pressure of the laser gas in the container (6) can drop too much, causing abnormal arc discharge in the electrode section. , it is also possible to prevent a failure in which the ``rrL pole portion is destroyed.

Note that as the switch, a valve operated by air pressure may be used instead of a solenoid valve or a three-way solenoid valve operated by electricity.

In addition, the types of the pressure gauge (28) include a Bourdon tube type pressure gauge, one using a semiconductor sensor, a manometer type,
It may be of any type, such as the Villany type.

By the way, in each L2 example, a case was shown in which a switch was provided on the gas exhaust side and two branched paths were provided, but a switch was provided on the gas injection side, that is, between the cylinder (21) and the container (6). This embodiment also produces the same effects as the above embodiment.

[Effects of the Invention] As explained above, this invention branches the gas exhaust route into two routes, sets the exhaust flow rate of one route to be slightly higher than the gas injection Ktm, and the other route to be slightly lower, and alternately By switching to selectively open and flow, the discharge flow rate can be set to a value close to the injection flow rate, allowing for slow pressure control, reducing the number of times the switch is turned on and off. This has the effect of increasing the lifespan of the device and making the laser oscillator less likely to fail and highly reliable.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a path of a gas laser oscillator equipped with a gas supply/exhaust device showing one embodiment of the present invention, FIG. 2 is an explanatory diagram showing another embodiment of the device of the invention, and FIG. 3 is a conventional diagram. FIG. 2 is an explanatory diagram corresponding to FIG. 1 showing a path of a gas laser oscillator equipped with a gas supply/exhaust device. In the figure, (6) is a laser gas container. (11) is a gas laser oscillator, (28) is a pressure gauge,
(42), (43) are switches (solenoid valves), (44) is one branch route, (45) is the other branch route, (50) is a switch (three-way solenoid valve), Q is the injection gas flow rate . Ql is a discharge flow rate slightly higher than Q, and Q2 is a discharge flow rate slightly lower than Q. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2

Claims (1)

[Claims] In a gas laser oscillator, which is equipped with a laser gas container filled with laser gas for laser oscillation, and which continuously supplies and exhausts the laser gas into the container for gas exchange, the exhaust path is branched into two, and one branch is connected to the other branch. One route is set to a discharge flow rate slightly higher than the injection gas flow rate, and the other branch route is set to a discharge flow rate slightly lower than the injection gas flow rate. Gas in a gas laser oscillator, characterized in that a switch is provided for selectively opening and circulating one branch path in response to an upper limit setting pressure signal and selectively opening and circulating the other branch path in response to a lower limit setting pressure signal from the pressure gauge. Supply and exhaust equipment.