JPH0453552Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an air purge tube for a radiation thermometer that sends air into the measurement optical path of a radiation thermometer to remove foreign matter from the measurement optical path, and particularly relates to an air purge tube for a radiation thermometer that removes foreign matter from the measurement optical path. The present invention relates to an air purge tube that can effectively eliminate foreign matter in a measurement optical path with a flow of air.

BACKGROUND ART One type of thermometer is a radiation thermometer that receives radiant energy emitted from a temperature-measuring object and measures the temperature of the temperature-measuring object from the magnitude of the radiant energy. In such radiation thermometers, foreign matter such as smoke, dust, oil smoke, etc. is present in the path through which the radiant energy emitted from the object to be measured enters the radiation thermometer, that is, in the measurement optical path of the radiation thermometer. Then,
Radiant energy is reflected or absorbed, impairing temperature measurement accuracy. For this reason, conventional air purge tubes have a cylindrical shape and are attached to the tip of the radiation thermometer so that the measurement optical path passes through the cylinder, and send air into the cylinder to remove foreign matter from the measurement optical path. It is widely used from

For example, the one shown in FIG. An annular air reservoir 4 is formed between them, and air is supplied from a supply port 5. The air supplied into the air reservoir 4 is distributed at second intervals at equal angular intervals around the center of the measurement optical path of the radiation thermometer 6, that is, the axis l of the main body 3.
Multiple (for example, about 6) provided in block 2
It is ejected from the small hole 7 of the first block 1, collides with the wall surface 8 of the first block 1, is reflected, and then flows out along the axis l within the measurement optical path. This outflow of air eliminates foreign substances such as smoke and dust from the measurement optical path.

Problems to be solved by the invention By the way, in such an air purge tube, in order to effectively eliminate foreign substances in the measurement optical path, it is desirable that the air in the measurement optical path be in a laminar flow state without stagnation. It can be done. However, conventional air purge tubes are not always fully satisfactory in this respect, and may cause pulsation or turbulence, causing foreign matter to remain in the measurement optical path, or attract foreign matter into the measurement optical path from outside. Something happened.

For example, regarding the air purge pipe shown in Figure 4 above, when we investigated the flow state of the air by adding cigarette smoke to the supplied air, we found that a generally good laminar flow state was obtained. When the flow rate is low, pulsation tends to occur, and when the flow rate is high, turbulence tends to occur, and the flow rate is unstable depending on the amount of air supplied.

Means for Solving the Problems The present invention was developed against the background of the above circumstances, and its purpose is to create an air purge tube in which the air sent into the measurement optical path is always in a good laminar flow state. Our goal is to provide the following.

In order to achieve such an object, the present invention provides an air purge tube for a radiation thermometer that sends air into the measurement optical path of a radiation thermometer to remove foreign matter from the measurement optical path, which comprises: (a) said measurement optical path; (b) a cylindrical main body attached to the tip of the radiation thermometer so that the air passes through the cylinder; and (b) the air is supplied from a supply port formed in the main body and provided on the outer periphery of the main body. (c) an annular first air reservoir provided in the inner circumference of the main body at a position spaced apart from the first air reservoir in the axial direction of the main body, and substantially uniform around the axis; a second air reservoir communicated with the first air reservoir;
(d) is attached to the main body so as to constitute an inner wall of the second air reservoir, and allows the air that has flowed into the second air reservoir from the first air reservoir to pass approximately uniformly into the measurement optical path. It is characterized by having a cylindrical air filter that allows the air to flow out.

Effect of operation and invention In such an air purge tube for a radiation thermometer, the air supplied from the supply port is first stored in the annular first air reservoir formed in the main body, and then, The air flows into a second air reservoir provided in communication with the first air reservoir. Second
Since the air reservoirs are communicated with the first air reservoir approximately evenly around the axis of the main body, the air supplied into the first air reservoir flows into the second air reservoir approximately evenly around the axis of the main body. I am made to do so. Then, the air flowing into the second air reservoir is
The air filter constituting the inner wall of the second air reservoir is passed approximately evenly around the axis of the main body,
It flows out into the cylinder of the main body, that is, into the measurement optical path of the radiation thermometer.

Here, the pressure distribution of the air that has passed through the two air reservoirs and the air filter is made uniform when the flow direction changes in the process or when it passes through the air filter, and the air that flows out from the air filter The measuring optical path can be caused to flow in a smooth and even flow, that is, in a laminar state. In particular, since the air purge tube of the present invention is equipped with an air filter, it can maintain a stable laminar flow state compared to, for example, an air purge tube that only changes the flow direction as shown in FIG. You will be able to get it. This prevents foreign matter from staying inside the cylinder, that is, within the measurement optical path of the radiation thermometer due to pulsation or turbulence, or from drawing foreign matter into the measurement optical path from the outside. temperature measurement accuracy is improved.

In addition, the air filter has a cylindrical shape and is designed to allow air to pass from the outside to the inside. Compared to the case where an air filter is used, an equivalent air passage area can be obtained with a smaller diameter size, and the air purge tube can be configured to be smaller and lighter.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 10 denotes a radiation thermometer that measures the temperature by condensing radiant energy emitted from a temperature-measuring object (not shown) onto a photoelectric conversion element using a condensing lens 12 and converting it into an electrical signal. be. The radiation thermometer 10 of this embodiment is installed in an environment with high temperatures and a lot of foreign matter such as dust, and is cooled by being stored in a water-cooled pipe 14 through which cooling water flows. At the same time, an air purge tube 16 and a sighting tube 18 are attached to the tip to exclude foreign matter such as dust from the measurement optical path of the radiation thermometer 10, which is the incident path of radiant energy. Dot-dashed line m in Figure 1
is the axis of the radiation thermometer 10, that is, the center line of the measurement optical path, and both the air purge tube 16 and the sighting tube 18 have a cylindrical shape, and are arranged so that their axes coincide with the center line m. It is set up. Note that FIG. 1 shows a state in which the radiation thermometer 10, air purge tube 16, and sighting tube 18 are separated from each other in the axial direction. Further, 20 is a cover of the radiation thermometer 10.

The air purge pipe 16 is shown in FIGS.
As shown in detail in the figure, the first block 22 and the second block made of aluminum casting are integrally screwed together.
It has a cylindrical body 26 made up of blocks 24. Both ends of the first block 22 are provided with outward flanges 28 and 30, respectively, and the main body 26 has its axis l aligned with the center line m, as described above.
In other words, it is attached to the tip of the radiation thermometer 10 via the flange 28 so that the measurement optical path passes through the cylindrical interior of the main body 26.
Further, the sighting tube 18 is attached to the other flange 30.

The second block 24 has a smaller diameter and is shorter than the first block 22, and an annular first air reservoir 32 is formed between them. A supply port 34 provided in the first block 22 is opened to this first air reservoir 32, and a nipple 3
Pressure air is supplied from an unillustrated air supply pipe connected to 6. As is clear from FIG. 3, the supply port 34 is provided eccentrically with respect to the axis l of the main body 26, and supplies air to the annular first air reservoir 32 from a tangential direction. Therefore, from the supply port 34 to the first
The air supplied into the air reservoir 32 is made to flow within the first air reservoir 32 in the circumferential direction.

The second block 24 is screwed onto the first block 22 at one end thereof, that is, the end located on the flange 28 side, and is hermetically sealed with an O-ring 38. However, the other end is provided with a flange-like protrusion 40 that protrudes toward the outer circumferential side, and the distance between it and the inner circumferential surface of the first block 22 is only slightly narrowed. This protrusion 40 connects the supply port 34 to the first air reservoir 32.
This restricts the air that has flowed into the first air reservoir 32 from directly flowing out to the other end of the second block 24. As a result, the air supplied from the supply port 34 is temporarily stored in the first air reservoir 32, and then Protrusion 40
and the inner circumferential surface of the first block 22 to flow out into the second air reservoir 42.

The second air reservoir 42 is provided on the inner periphery of the first block 22 adjacent to the first air reservoir 32 in a direction parallel to the axis 1, and communicates with the first air reservoir 32 over its entire circumference. I'm forced to. Therefore, the air in the first air reservoir 32 is made to flow approximately evenly into the second air reservoir 42 around the axis l.

On the other hand, an air filter 44 having a cylindrical shape is provided concentrically at the other end of the second block 24, and constitutes the inner wall of the second air reservoir 24. This air filter 44 is made of a sintered metal porous body equivalent to type BC3 (bronze casting), and its filtration accuracy is about 120 μm. One end of the air filter 44 is fixed to the second block 24 with an adhesive or the like, and the other end is fixed to the second block 24 with an adhesive or the like.
When the block 24 is screwed onto the first block 22, the flange 30 of the first block 22
The side ends are brought into airtight contact with a filler 46 interposed therebetween. Therefore, the air that has almost evenly flowed into the second air reservoir 42 is passed from the entire outer circumferential surface of the air filter 44 to the inner circumferential side almost evenly, and the air is allowed to flow into the cylinder of the air purge pipe 16,
That is, it is sent into the measurement optical path of the radiation thermometer 10. Then, along the center line m of the measurement optical path, the air is caused to flow from the air purge tube 16 into the sighting tube 18 toward the distal end side.

The air purge pipe 16 of this embodiment is as follows:
Pressure air supplied from the supply port 34 is supplied to the two air reservoirs 32, 42 and the air filter 44.
Since the air is sent out into the measurement optical path through a The measurement optical path can be moved in a flow state, that is, in a smooth, even flow. In particular, since this air purge pipe 16 is equipped with an air filter 44, it is possible to change the amount of air supplied, for example, compared to an air purge pipe that only changes the flow direction as shown in FIG. Regardless of the situation, a stable laminar flow state can always be obtained.
This prevents foreign objects from staying in the measurement optical path due to pulsation or turbulence, or from drawing foreign objects into the measurement optical path from the outside, so that foreign objects can be effectively removed from the measurement optical path. As a result, the temperature measurement accuracy of the radiation thermometer 10 is improved.

In addition, since the air filter 44 has a cylindrical shape, it is different from the case where, for example, a disk-shaped air filter with a circular hole formed in the center for securing the measurement optical path of the radiation thermometer 10 is used. , an equivalent air passage area can be obtained with a smaller diameter dimension, and the air purge pipe 16 can be configured to be smaller and lighter.

In addition, when we investigated the flow state of air by blowing cigarette smoke into the supply port 34 of the air purge pipe 16 of this embodiment, we found that compared to the conventional example shown in FIG. It was also confirmed that air flows in a stable laminar flow state.

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention can also be implemented in other embodiments.

For example, in the above embodiment, a sintered metal porous body is used as the air filter 44, but the material may of course be changed. It is also possible to employ a filter. Moreover, the filtration accuracy can also be changed as appropriate.

Furthermore, although the second air reservoir 42 in the embodiment described above is communicated with the first air reservoir 32 along its entire circumference, a partition plate or the like is provided at the portion where the protrusion 40 is provided, and a plurality of communication channels are provided at equal angular intervals. There is no problem even if holes are formed.

Further, the second air reservoir 42 is provided closer to the tip of the measurement optical path than the first air reservoir 32 in the direction parallel to the axis l, that is, on the left side in FIG. There is no problem even if the position of is reversed.

Further, the main body 26 in the above embodiment is composed of two blocks 22 and 24 made of aluminum casting, but the structure, material, etc. are determined as appropriate in consideration of the usage conditions of the radiation thermometer 10, etc. be.

Although no other examples are given, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a radiation thermometer equipped with an air purge tube, which is an embodiment of the present invention, and is a front view showing each part separated in the axial direction. FIG. 2 is a longitudinal sectional view of the air purge pipe of FIG. 1. FIG. 3 is a - sectional view in FIG. 2. FIG. 4 is a sectional view illustrating an example of a conventional air purge pipe. 10...Radiation thermometer, 16...Air purge pipe, 26...Main body, 32...First air reservoir, 34
...Supply port, 42...Second air reservoir, 44...
...Air filter, l...Axis of air purge tube, m...Center line of measurement optical path.

Claims (1)

[Claims for Utility Model Registration] An air purge tube for a radiation thermometer that sends air into a measurement optical path of a radiation thermometer to remove foreign matter from the measurement optical path, the air purge tube for a radiation thermometer, which a cylindrical main body attached to the tip of the radiation thermometer; and an annular first air reservoir formed within the main body and to which the air is supplied from a supply port provided on the outer periphery of the main body. , an annular shape provided on the inner circumference of the main body at a position spaced apart from the first air reservoir in the axial direction of the main body, and communicating with the first air reservoir approximately evenly around the axis; a second air reservoir attached to the main body so as to constitute an inner wall of the second air reservoir, and a second air reservoir configured to form an inner wall of the second air reservoir;
An air purge tube for a radiation thermometer, comprising a cylindrical air filter that allows the air that has flowed into the air reservoir to pass therethrough substantially uniformly and flows out into the measurement optical path.