JP3078798B1 - Gas laser oscillation device - Google Patents

Abstract

An object of the present invention is to achieve a balance between a filtration degree for oil mist, a low pressure loss for laser gas, and liquefied oil separation. SOLUTION: A circulation tube 26 which constitutes a circulation path of a laser gas 34 together with a discharge tube, a blower provided in a passage of the circulation tube 26, and an oil mist provided between the blower and an exhaust pump. And a filter 27a capable of trapping a laser beam. The filter 27a is formed in a cylindrical shape having at least a double layer structure so that the laser gas 34 passes from the outer layer to the inner layer.
3 to 1.0 mm, 1 to 5 mm thick cylindrical sintered metal 2
In the outer layer, a metal mesh 31 having an opening of 0.1 to 0.5 mm was wound around the inner layer so as to have a thickness of 10 to 50 mm. Accordingly, it is possible to prevent the oil mist from being mixed into the laser gas 34 and to reduce the lubricating oil in the blower, and to prevent a decrease in laser output and a failure of the blower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser oscillator using a blower.

[0002]

2. Description of the Related Art A conventional gas laser oscillator will be described with reference to FIG. A laser gas 2 is circulated in a discharge tube 1 made of a dielectric. Electrodes 3 provided around discharge tube 1,
The high-voltage power supply 5 connected to 4 generates a discharge 6 in the discharge tube 1. The laser gas 2 is excited by the discharge 6 and is output as a laser beam 9 to the outside through the total reflection mirror 7 and the partial reflection mirror 8. The laser gas 2 is sent by a blower 11 inside a circulation tube 10 forming a circulation path of the laser gas 2 together with the discharge tube 1, and the heat exchanger 12 is used to lower the temperature of the laser gas 2 raised by the discharge 6 and the blower 11. , 13 are arranged.

FIG. 9 is a detailed view of the blower 11 and its peripheral parts. Since the molecules of the laser gas 2 are dissociated by the discharge 6 and the purity of the laser gas 2 deteriorates with the passage of time, the dissociated laser gas 2 is discharged at a constant rate, and a new laser gas 2 having the same amount as the discharged amount is discharged. Need to replenish. In order to discharge the laser gas, a certain amount of the laser gas 2 is discharged from the circulation pipe 10 through the exhaust pipe 23 by the vacuum pump 24. On the other hand, fresh laser gas 2 is supplied from the circulation pipe 10 through the fresh gas supply pipe 25. The laser gas pressure inside the discharge tube 1 and inside the circulation tube body 10 is 50 to 100 Torr depending on the balance between the laser gas discharge and the supply.
r is maintained.

Next, the structure and operation of the blower 11 will be described. The blower 11 includes a blowing unit 14 and driving units 15a and 15b sandwiching the blowing unit 14, and the driving units 15a and 15b are connected to each other. Blower 11
Is filled with the laser gas 2 in the same manner as in the circulating tube 10 in both the blowing unit 14 and the driving units 15a and 15b.
The blower 14 is directly connected to the circulation pipe 10 in the vertical direction of FIG. A gas blower 16 such as a rotary wing housed in a blower unit 14, a drive unit 17 such as a motor housed in a drive unit 15 a, and a gear unit 18 housed in another drive unit 15 b are mutually connected to a shaft 19. Connected by
The laser gas 2 is circulated in the circulation pipe 10 by rotating the gas blowing means 16 such as a rotary wing by the driving means 17 such as a motor. For lubrication and cooling of the driving means 17 and the gear section 18, the driving sections 15a, 1
The lubricating oil 21 is stored in the lubricating oil 5b. Therefore, the laser gas 2 in the driving units 15a and 15b contains mist-like oil generated from the lubricating oil 21, so-called oil mist 22. However, in the circulating pipe body 10,
When the oil mist 22 enters, the oil mist 22 is mixed into the laser gas 2 circulating in the circulation pipe 10 and the discharge tube 1, causing a problem that the purity of the laser gas 2 is reduced and the laser output is reduced. I do. Therefore, the gap around the shaft 19 is sealed by the shaft seal 20, so that the oil mist of the driving units 15 a and 15 b does not enter the blowing unit 14.

[0005] However, it is impossible to completely fill the gap between the shafts 19, which are rotating bodies, even though they are sealed.
Strictly speaking, there is a slight gap. If the pressure in the driving units 15a and 15b is higher than the blowing unit 14, the flow of the laser gas 2 from the driving units 15a and 15b to the blowing unit 14 is generated according to the pressure gradient, and the oil mist 22 is generated together with the laser gas 2. Will enter the air blower 14. In order to prevent this, a certain amount of gas in the driving units 15a and 15b is sucked and discharged by the vacuum pump 24 through the driving unit exhaust pipe 26, and the pressure in the driving units 15a and 15b is constantly increased.
So that it is lower than the internal pressure. In this state, the laser gas 2 flows from the blowing section 14 to the driving sections 15a and 15b through the delicate gap of the shaft seal 20, and the oil mist 22 can be prevented from entering the blowing section 14.

[0006] The oil mist 22 communicates with the exhaust pipe 26 of the drive unit and is discharged to the vacuum pump 24 side by the suction of the gas from the drive units 15a and 15b. However, two problems occur here. First, the drive unit 15 is driven by oil mist discharge.
The lubricating oil 21 in a and 15b may gradually decrease and become insufficient over time. As a result, the driving means 1
There is a possibility that adverse effects such as seizure of the gear 7 and the gear portion 18 due to insufficient lubricating oil may occur. Second, the inside of the drive unit exhaust pipe 26, the exhaust pipe 23, the circulation pipe 10, etc.
Due to the vacuum state of about orr, oil mist that should be discharged to the vacuum pump 24 side through the drive unit exhaust pipe 26 diffuses to the exhaust pipe 23 side and enters the circulation pipe body 10 due to the so-called vacuum diffusion phenomenon. By doing so, the possibility of mixing in the laser gas 2 is conceivable. In order to prevent these adverse effects, it is necessary to selectively collect only the oil mist from the laser gas 2 sucked from the driving units 15a and 15b, liquefy the collected oil mist, and then return the collected oil mist to the inside of the driving unit again. Needed. With this configuration, it is possible to prevent oil mist from entering the circulation pipe and decrease lubricating oil in the drive unit. Generally, a filter 27 is provided between the drive unit exhaust pipe 26 and the vacuum pump 24 based on this idea.

The above is the configuration and operation of the conventional laser oscillation device.

[0008]

The function of the filter 27 is to selectively collect only the oil mist from the laser gas 2 and to liquefy the oil mist after the collection into the drive units 15a and 15b again. It is necessary to return. It is also required that this function can be maintained for a long time.
In order to satisfy these requirements, it is necessary to have the following three characteristics. First, a high degree of filtration that can collect oil mist. Second, the pressure loss when the laser gas 2 passes is small, that is, low pressure loss. If the pressure loss is large, a sufficient amount of the laser gas 2 cannot be discharged from the driving units 15a and 15b, and the purpose of lowering the pressure in the driving units 15a and 15b below the pressure in the blowing unit 14 cannot be achieved. I will. Third, the collected and liquefied oil mist, so-called liquefied oil, can be quickly separated from the filter 27, that is, the separation property of the liquefied oil. If the liquefied oil mist stays without being separated from the filter 27, the filter 27 will become clogged with time and the pressure loss will increase. The drive unit 15
Since the liquefied oil cannot be returned to a and 15b, the lubricating oil also decreases. Therefore, the filter 27
The liquefied oil after collection is quickly separated, and the driving unit 1
It is necessary to return to inside 5a, 15b.

Heretofore, it has been very difficult to achieve all three factors at the same time. This is because it is relatively easy to obtain a degree of filtration of oil mist with a resin foam, a hollow fiber material, paper, etc., which are often used as a general filter, and the pressure loss is initially low. However, the collected oil mist immediately turns into a highly viscous liquefied oil, so that its separability from the filter is extremely poor.
Also, due to the poor separation property, even if the pressure loss of the filter is initially low, the filter immediately becomes clogged during use and the pressure loss increases. Conventionally, attempts have been made to use a sintered metal obtained by sintering metal particles having a particle diameter of about several hundred microns in a cylindrical shape as a filter. By adopting a metal filter element, the aim was to improve the separability of liquefied oil and prevent a long-term increase in pressure loss. However, if the metal particle diameter is reduced in order to obtain a sufficient degree of filtration, if a large amount of oil mist enters, the liquefied oil cannot be discharged sufficiently, resulting in clogging and an increase in pressure loss. Conversely, if the metal particle diameter is increased to reduce the pressure loss, the dilemma that the filtration degree decreases cannot be avoided, and in some places, the filtration degree and the pressure loss are balanced, which is a fundamental problem. It could not be solved.

[0010] Accordingly, an object of the present invention is to provide a filter that balances the three factors of the degree of filtration for oil mist, low pressure loss for laser gas, and the ability to separate liquefied oil, so that oil mist is mixed into the laser gas from the blower. To prevent the laser output from lowering and the lubricating oil inside the blower to prevent the fan from malfunctioning.
An object of the present invention is to provide a highly reliable gas laser oscillation device that can be used stably for a long period of time.

[0011]

According to a first aspect of the present invention, there is provided a gas laser oscillation apparatus, comprising:
A discharge tube forming a flow path of the laser gas, a circulating tube forming a gas circulation path together with the discharge tube, a blowing unit connected to a path of the circulating tube, and a driving unit adjacent thereto; A blower that causes a laser gas to flow in the axial direction of the discharge tube when the gas blower is driven by the drive unit, an exhaust pump connected to the circulation pipe and the drive unit, and an exhaust gas provided between the drive unit and the exhaust pump. from laser gas sucked from the drive unit in the pump a gas laser oscillation apparatus and a filter capable trapping oil mist, filter,
At least each has a cylindrical shape having a layer structure of two or more layers functioning as a filter, and is configured so that the laser gas passes from the outer layer to the inner layer, the inner layer is a cylindrical sintered metal, and the outer layer is a metal mesh wound around the inner layer. It is characterized by being formed by attaching.

[0012] In this way, the filter, at least it
Each of them has a cylindrical structure having two or more layers functioning as a filter, and is configured so that the laser gas passes from the outer layer to the inner layer. The inner layer is a cylindrical sintered metal, and the outer layer is a metal mesh wound around the inner layer. Since the filter is formed by attaching the filter, it is possible to provide a filter that combines the three factors of the degree of filtration of the oil mist in the laser gas, the low pressure loss of the laser gas, and the liquefied oil separation. As a result, it is possible to prevent oil mist from being mixed into the laser gas and to reduce the amount of lubricating oil in the blower, and to prevent a decrease in laser output and a malfunction of the blower, thereby providing a reliable gas laser oscillation that can be used stably for a long period of time. Equipment can be provided.

According to a second aspect of the present invention, in the gas laser oscillation device according to the first aspect, the sintered metal has a particle diameter of 0.3 to 1.0 m.
m, thickness 1 to 5 mm, and the metal mesh
The thickness was 1 to 0.5 mm and the thickness was 10 to 50 mm.

The laser gas mixed with the oil mist in the filter according to the above configuration first passes through the outer layer.
The outer layer has a structure in which a metal mesh having an opening of 0.1 to 0.5 mm is wound around the inner layer so as to have a thickness of 10 to 50 mm. This structure has a very high density in the direction in which the gas passes, because there are multiple mesh layers. On the other hand, the direction perpendicular to the direction in which the gas passes has a sparse structure. The laser gas mixed with the oil mist travels in a direction that is denser than the metal mesh, so that the laser gas efficiently collides with the metal mesh, and is condensed and liquefied during the collision process to become liquefied oil. Although the liquefied oil tends to drop by its own weight, the metal mesh is sparse in this direction, so that the liquefied oil descends very smoothly downward, is discharged out of the metal mesh, and returns to the inside of the drive unit.

By passing the metal mesh from the outer periphery to the inner periphery, oil mist in the laser gas is almost eliminated. The laser gas in a state in which the oil mist is slightly mixed then passes through the inner layer. The inner layer has a particle diameter of 0.3 to
It is a cylindrical sintered metal with a thickness of 1.0 mm and a thickness of 1 to 5 mm. Compared with a metal mesh, it has a high-density, isotropic, and homogeneous structure to increase the filtration degree. A small amount of oil mist can be collected. Most of the oil mist is filtered by the outer metal mesh, and the amount of oil mist collected by the sintered metal is relatively small. There is no cause.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are shown in FIGS.
It will be described based on. FIG. 1 is an explanatory diagram showing details and functions of a filter according to an embodiment of the present invention. The configuration other than the filter is the same as that of the conventional example, and the same reference numerals are given to the same configuration as the conventional example, and the description will be omitted.

The filter 27a is roughly composed of a casing 32 and an element 33. The structure is such that the element part 33 is housed in the casing part 32, and after the laser gas 34 introduced from the driving part exhaust pipe 26 below the casing part 32 passes through the element part 33, the casing part 32 32 will be discharged from the upper part. The element part 33 is formed of a two-layer cylinder whose axis is vertical. The inner layer is made of a sintered metal 28 obtained by sintering metal particles into a cylindrical shape as in the conventional example, and has a particle diameter of 0.3 to 1.0 mm and a radial thickness of 1 to 5 mm. is there. The outer layer has an aperture of 0.1 to 0.1.
It is made of a metal mesh 31 of 5 mm wound in a cylindrical shape around the inner layer of the sintered metal 28, and has a radial thickness of 10 to 50 mm. A lid 29 is attached to the lower part so that the laser gas 34 does not enter from the lower part of the two-layer cylinder.

Next, the operation will be described. Laser gas 3 mixed with oil mist sucked from the drive unit
Numeral 4 passes through the drive unit exhaust pipe 26 and enters the filter 27 a through a hole at the lower part of the casing 32.

The laser gas 34 mixed with the oil mist in the filter 27a passes from the outside to the inside of the element portion 33. First, it passes through a metal mesh 31 which is an outer layer. The metal mesh 31 has a structure wound around the sintered metal 28 of the inner layer. This structure has a very high density in the horizontal direction of the drawing, that is, in the direction in which the gas 34 passes, because there are multiple layers of mesh layers. On the other hand, the vertical direction in the figure, that is, the direction perpendicular to the direction in which the gas 34 passes, has a sparse structure. Since the laser gas 34 mixed with the oil mist travels in the lateral direction of the metal mesh 31, that is, in a dense direction, the laser gas 34 collides with the metal mesh 31 efficiently, and is condensed and liquefied in the collision process to become the liquefied oil 30. The liquefied oil 30 tends to drop by its own weight. Since the metal mesh 31 is sparse in the vertical direction, the liquefied oil 30 descends extremely smoothly downward, is discharged out of the metal mesh 31, and is driven through the lower hole of the casing 32 to the drive unit exhaust pipe 26. It descends down and is returned to the drive section.

By passing through the metal mesh 31 from the outer periphery to the inner periphery, oil mist in the laser gas 34 is almost eliminated. The laser gas 34 slightly mixed with the oil mist then passes through the inner layer of the sintered metal particles 28. As compared with the metal mesh 31, the sintered metal particles 28 have a high density and a uniform
It has a homogenous structure and can collect even a slight oil mist in the laser gas 34. Most of the oil mist is filtered by the outer metal mesh 31, and the amount of oil mist collected by the sintered metal particles 28 is relatively small. Regardless, there is no clogging.

Thus, the point of the present invention is that the filter element has a two-layer structure having different characteristics. The outer layer has anisotropy in density in the direction in which the laser gas 34 passes and the direction in which the liquefied oil descends. With this structure, a large amount of oil mist can be collected, and the liquefied oil can be discharged downward in the direction of gravity without causing clogging. However, due to this anisotropy, the oil mist cannot be completely collected, and some oil mist passes through. This is because particles that move under a low pressure of about 50 to 100 Torr generally do not proceed straight in one direction, but move in a direction along the pressure gradient as a whole while performing random movement. Can be seen. This is a so-called pruning phenomenon. In order to completely capture this random movement, it is desirable that the filter element be homogeneous and isotropic. Since the filter outer layer of this embodiment has a very sparse structure in the vertical direction in the direction of gravity, it can hardly collect oil mist traveling in that direction. Therefore, a small amount of oil mist passes through the outer layer, but the remaining oil mist is completely collected by the inner layer, which is dense, homogeneous and isotropic. That is, the outer layer performs the rough removal of the oil mist, and the inner layer performs the complete collection of the oil mist.

If only the inner layer of the sintered metal particles 28 is used, the state is the same as in the conventional example, and the discharge of the liquefied oil cannot catch up with a large amount of oil mist, causing clogging. On the other hand, if only the outer metal mesh 31 is used, a sufficient degree of filtration cannot be secured.

According to the structure of this embodiment, since the outer layer and the inner layer cover the respective weak points and draw out their respective strengths, an ideal filter which cannot be realized conventionally, that is, an oil mist in the laser gas 34, And a filter that achieves a balance between the three factors: low filtration loss, low pressure loss with respect to the laser gas 34, and liquefied oil separation.

As shown in FIGS. 2 to 5, it has been experimentally confirmed that both the metal mesh 31 of the outer layer and the sintered metal particles 28 of the inner layer have the optimum specifications for maximizing their characteristics. FIG. 2 is a graph showing the optimum value of the metal mesh opening. The solid line A indicates the liquefied oil separating property, and the broken line B indicates the amount of collected oil mist. The optimum value of the balance between the oil mist trapping amount B and the liquefied oil separation A is 0.1
It can be seen that it is ~ 0.5 mm. FIG. 3 is a graph showing an optimum value of the radial thickness of the metal mesh, and a solid line C indicates a pressure loss. It can be seen that the optimal value that balances the pressure loss C and the amount of collected oil mist B is 10 to 50 mm. FIG. 4 is a graph showing the optimum value of the sintered metal particle diameter. It can be seen that the optimum value that balances the amount of collected oil mist B and the liquefied oil separability A is 0.3 to 1.0 mm. FIG. 5 is a graph showing the optimum value of the radial thickness of the sintered metal particle diameter. The optimal value in which the amount of collected oil mist B and the pressure loss C are balanced is 1 to 5
mm.

FIG. 6 shows the performance as an oil mist collecting filter in the embodiment of the present invention and the conventional example, and shows the amount of lubricating oil remaining in the blower driving section with respect to the operation time. In the conventional example, since the oil mist passes through the filter and is discharged with time, the remaining amount of the lubricating oil is decreasing. In this state, an adverse effect such as a failure of the blower occurs due to a shortage of lubricating oil. on the other hand,
In the embodiment of the present invention (example of the present invention), oil mist is efficiently collected and separated from the filter,
Since the lubricating oil can be returned to the driving section again, the phenomenon of lubricating oil does not occur over time, and the long-term reliability of the blower can be ensured.

FIG. 7 shows a comparison of the filter performance between the embodiment of the present invention and the conventional example, and shows the time change of the laser output. In the conventional example, oil mist that has passed through the filter over time is mixed into the laser gas 34, which causes a decrease in laser output. On the other hand, in the embodiment of the present invention (example of the present invention), since the oil mist hardly mixes into the laser gas 34, it can be seen that a stable laser output can be secured for a long period of time.

Although the filter has two layers, the filter may have at least two or more layers.

[0028]

As is apparent from the above description, according to the gas laser oscillation device according to the first aspect of the present invention, the filter has a cylindrical shape having at least two or more layers each functioning as a filter. The laser gas is configured to pass from the outer layer to the inner layer.
Since it is a cylindrical sintered metal having a thickness of 3 to 1.0 mm and a thickness of 1 to 5 mm, and the outer layer is formed by winding a metal mesh having an opening of 0.1 to 0.5 mm around the inner layer so as to have a thickness of 10 to 50 mm, Thus, it is possible to provide a filter that achieves both the degree of filtration of oil mist in laser gas, low pressure loss for laser gas, and liquefied oil separation. As a result, it is possible to prevent oil mist from being mixed into the laser gas and to reduce the amount of lubricating oil in the blower, and to prevent a decrease in laser output and a malfunction of the blower, thereby providing a reliable gas laser oscillation that can be used stably for a long period of time. Equipment can be provided.

According to the second aspect, the sintered metal has a particle diameter of 0.3
~ 1.0mm, thickness 1 ~ 5mm, metal mesh,
Since the mesh size is 0.1 to 0.5 mm and the thickness is 10 to 50 mm, the specifications are the most suitable for maximizing the characteristics of the metal mesh and the sintered metal particles.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing details of a filter and a function thereof in an embodiment of the present invention.

FIG. 2 is a graph showing an optimum value of a metal mesh opening in the embodiment of the present invention.

FIG. 3 is a graph showing an optimum value of a radial thickness of a metal mesh according to the embodiment of the present invention.

FIG. 4 is a graph showing an optimum value of a sintered metal particle diameter in the embodiment of the present invention.

FIG. 5 is a graph showing an optimum value of a thickness of a sintered metal particle in a radial direction in the embodiment of the present invention.

FIG. 6 is a graph showing a comparison of filter performance between the embodiment of the present invention and a conventional example, and is a graph showing a remaining amount of lubricating oil in a blower driving unit with respect to an operation time.

FIG. 7 is a graph showing a comparison of filter performance between an embodiment of the present invention and a conventional example, and is a graph showing laser output with respect to operation time.

FIG. 8 is a schematic diagram illustrating the entire configuration of a conventional gas laser oscillation device.

FIG. 9 is a detailed view of a blower and its peripheral parts in a conventional gas laser oscillation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge tube 2 Laser gas 3 Electrode 4 Electrode 5 High voltage power supply 6 Discharge 7 Total reflection mirror 8 Partial transmission mirror 9 Laser beam 10 Circulation tube 11 Blower 12 Heat exchanger 13 Heat exchanger 14 Blower 15 Drive 16 Gas blower Means 17 Drive means 18 Timing gear 19 Shaft 20 Shaft seal 21 Lubricating oil 22 Oil mist 23 Exhaust pipe 24 Vacuum pump 25 Fresh gas supply pipe 26 Drive exhaust pipe 27, 27a Filter 28 Sintered metal particles 29 Lid 30 Liquefied oil 31 Metal Mesh 32 Casing part 33 Element part 34 Laser gas containing oil mist 35 Laser gas without oil mist

Claims (2)

(57) [Claims] A discharge tube forming a flow path of a laser gas;
A circulating pipe that forms a gas circulation path together with the discharge tube, a blowing unit connected to a path of the circulating pipe, and a driving unit adjacent thereto; gas blowing means in the blowing unit is controlled by the driving unit. A blower that causes the laser gas to flow in the axial direction of the discharge tube by being driven; an exhaust pump connected to the circulation pipe and the drive unit; and the exhaust pump provided between the drive unit and the exhaust pump. in a gas laser oscillation apparatus and a filter capable collecting oil mist from laser gas sucked from said drive unit, wherein the filter, the machine at least each as a filter
A cylindrical structure with a layer structure of two or more layers that allows the laser gas to pass from the outer layer to the inner layer.The inner layer is a cylindrical sintered metal, and the outer layer is formed by winding a metal mesh around the inner layer. A gas laser oscillation device characterized by the above-mentioned. 2. The sintered metal has a particle diameter of 0.3 to 1.0 m.
m, thickness 1 to 5 mm, and the metal mesh
The gas laser oscillation device according to claim 1, wherein the gas laser oscillation device has a thickness of 1 to 0.5 mm and a thickness of 10 to 50 mm.