JPH0317232B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-power laser oscillator.

Conventional configuration and its problems A high-speed axial flow laser oscillator is known as a high-output laser oscillator.

FIG. 1 shows the general configuration of a high-speed axial flow laser oscillator. 1 is a discharge tube, 2 and 4 are heat exchangers, and 3 is a gas circulation pump. 7 is a medium gas inlet, 5 is a pipe, 6 is a gas flow direction, and arrow 8 is a laser beam.

In the above configuration, the laser gas is supplied into the discharge tube 1 by the gas circulation pump 3 through the pipe 5 and through the medium gas introduction section 7. is influenced by

FIG. 2 is a flow velocity distribution diagram of gas flowing inside the discharge tube 1, where a shows a case where the gas flow distribution is non-uniform and b shows a case where the gas flow distribution is uniform. Compared to a, b has a large discharge volume, stable discharge, can input a large amount of power, and has a large output.

Therefore, attempts have been made to make the flow velocity distribution within the discharge tube 1 closer to the state shown in diagram b by devising the structure of the medium gas introduction section 7.

3 to 6 show the structure of a conventional medium gas introduction section. A step-by-step explanation will be given below.

FIG. 3 is an example of an orifice type opening. 1 is a discharge tube, 70 is a reflecting mirror, and 71 is an orifice plate. When the gas flow 6 that has passed through the pipe 5 passes through the orifice plate 71, turbulence is promoted, and the flow velocity distribution becomes substantially uniform as shown in FIG. 2b before flowing into the discharge tube 1.

FIG. 4 is an example of a donut-shaped opening. Reference numeral 72 denotes an opening, and a uniform flow velocity distribution is obtained by ejecting gas from a donut-shaped gap formed by the cylindrical end surface of the discharge tube 1 and the inner tube end surface of the medium gas introduction section 7.

Figure 5 shows a slit 73 inside the medium gas introduction part.
This is an example of a case where

Figure 6 shows the nozzle type, and the laser gas is fed through the nozzle 74.
This is an example in which the liquid is ejected from the discharge tube 1, curves at a right angle, and flows into the discharge tube 1.

In all of these conventional examples, the cross-sectional area of the opening is made small and a pressure difference is obtained before and after the opening, thereby obtaining a locally high-speed flow and promoting turbulence. For this reason, the conductance of the opening is small, and the compression ratio of the gas circulation pump is large (for example, the inlet of the opening is 60Torr, and the inside of the discharge tube is 60Torr).
If it is 30Torr, the compression ratio is 2. ), and requires a large exhaust capacity under high pressure (more than 60 Torr in the above example). In addition, the types of pumps are limited, the size of the pump increases, power consumption increases, the amount of loss due to heat generation increases, the cooler for cooling the pump becomes large, and the price of the entire device decreases. occupied a large proportion.

Purpose of the Invention The present invention has been made to solve the above-mentioned conventional problems, and by increasing the conductance of the gas jet port at the inlet of the discharge tube, it promotes turbulence and makes the flow velocity distribution more uniform than before. The aim is to increase scale output, downsize the pump, and reduce costs.

Structure of the Invention The present invention achieves the above object, and includes a medium gas introduction section for introducing medium gas into the laser tube,
The laser tube has a structure that allows medium gas to flow at high speed in the laser tube, and the medium gas introduction part is provided with rotary blades that can be rotated by the gas flow, and when the gas passes through the rotary blade, the direction of the gas flow is changed, In addition to promoting turbulence, rotation is added to the gas flow to further increase the flow velocity near the inner wall, making the flow velocity portion uniform, and reducing the load on the gas circulation pump.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 7 shows an embodiment of the present invention. 1 is a discharge tube, and 75 is a rotary blade which is held in the inner tube of the medium gas introduction section 7 via a rotary bearing 76. 5 is piping, 6
is the gas flow direction, and 70 is a reflecting mirror. FIG. 8 shows an example of a rotor blade. Each blade has a twist θ about the axis of rotation.

When the gas flow 6 hits the blades, it rotates the rotor blades 75 and the gas flow itself is also bent, so that the laser gas as a whole moves through the discharge tube 1 in a spiral motion, increasing the flow velocity near the tube wall and creating a uniform flow velocity distribution. Create. Further, the gas hitting the edge of the blade and the gas leaving the edge further promote turbulence. Further, there is no reduction in conductance at the opening.

As described above, according to this embodiment, there is no need to narrow the opening to create turbulence as in the conventional system, and it is possible to achieve an ideal flow velocity distribution and promote turbulence without reducing conductance. be able to.

The gas pressure on the rotor inlet side is kept at 60 Torr, the same as before.
Therefore, the gas pressure inside the discharge tube is approximately 50 Torr (conventionally
30Torr), and the compression ratio of the circulation pump is as small as 1.2 (previously 2.0), allowing conventional pumps to operate with sufficient margin, resulting in a significant reduction in heat generation from the pump and downsizing of the pump cooling system. .
Furthermore, by increasing the gas pressure inside the discharge tube 1, it is possible to obtain approximately 1.7 times the output. This means that in order to obtain the same output, a smaller circulation pump is required and a significant cost reduction can be achieved.

Furthermore, the inertia of the rotor blades has the effect of absorbing small pulsating flows from the pump, which greatly contributes to output stability.

Effects of the Invention As described above, the present invention has a structure in which a medium gas flows into a laser tube through a medium gas introduction part, and a rotor blade that can be rotated by the gas flow is provided in the medium gas introduction part. This laser oscillator has the advantages of promoting turbulence in the medium gas in the laser tube, making the flow velocity distribution uniform, increasing the output, making the circulation pump smaller, and lowering the cost. .

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the general configuration of a high-speed axial flow laser oscillator, and Figure 2 is a diagram showing the flow velocity distribution in the laser tube, where a is an example of a nonuniform gas flow velocity distribution, and b is an example of a gas flow velocity distribution. Here is a uniform example. 3 to 6 are cross-sectional views of a conventional medium gas introduction part, and FIG. 7 is a cross-sectional view of a medium gas introduction part in an embodiment of the present invention.
FIG. 8 is a perspective view of a rotor blade used in one embodiment of the present invention. 1... Laser tube, 5... Piping, 6... Gas flow,
7...Medium gas introduction part, 70...Reflector, 75...
...rotor blade, 76...rotary bearing.

Claims (1)

[Claims] 1. A laser oscillator configured to flow a medium gas into a laser tube through a medium gas introduction section, and characterized in that the medium gas introduction section is provided with rotary blades that are rotatable by the gas flow.