JP3620023B2 - Pneumatic cylinder for vacuum chamber of fluorescent X-ray analyzer and fluorescent X-ray analyzer using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic cylinder used in a vacuum chamber of a fluorescent X-ray analyzer and a fluorescent X-ray analyzer using the same.
[0002]
[Prior art]
Conventionally, in the fluorescent X-ray analysis apparatus comprising a vacuum chamber to form a vacuum or helium atmosphere, excessive and for advancing and retracting the comb-shaped damping plate just before the detector to attenuate the X-ray filter to X-ray path In order to advance and retract the spectroscopic element, a pneumatic cylinder is used. In particular, as shown in the right side cross-sectional view of FIG. 6, there is a simple structure that can be directly attached to the outer wall (the outer surface of the wall) 1a of the vacuum chamber. In this pneumatic cylinder 27, the front surface 22a of the cylinder 22 having a cover in the front and rear in the axial direction A is attached so as to be in close contact with the outer wall 1a of the vacuum chamber. The piston 3 reciprocates in the axial direction A in the cylinder 22 by the pressure of air supplied to the ports 22d and 22e provided in the front part 22b and the rear part 22c of the cylinder.
[0003]
That is, when the supply of air to the port 22e at the rear part of the cylinder is stopped and the air is supplied to the port 22d at the front part of the cylinder, the piston 3 is pushed backward and moves (the state in FIG. 6), and vice versa. When the supply of air to the port 22d at the front part of the cylinder is stopped and the air is supplied to the port 22e at the rear part of the cylinder, the piston 3 is pushed forward and moves. The rear end portion of the rod-shaped piston rod 14 is fixed to the piston 3, and the front portion penetrates the front portion 22b of the cylinder and the wall 1 of the vacuum chamber, so that the front end portion 14a extends in the axial direction A in the vacuum chamber. Move back and forth. Here, the air supplied to the port 22d at the front part of the cylinder does not leak into the vacuum chamber from the hole 22f of the front part 22b of the cylinder provided for passing the piston rod 14 and the hole of the wall 1 of the vacuum chamber. As described above, the rod packing 15 through which the piston rod 14 penetrates closely is provided in the front portion 22b of the cylinder.
[0004]
When the piston rod 14 rotates about its axis, for example, when the comb-like attenuation plate is attached to the tip end portion 14a of the piston rod, the attenuation rate of the X-ray incident on the detector is also rotated. Therefore, the hole 22f of the front portion 22b of the cylinder is a non-rotating hole 22f that prevents the piston rod 14 from rotating about its axis when the piston rod 14 is inserted. That is, instead of making the piston rod 14 cylindrical, as shown in the front view of FIG. 7, the cross section perpendicular to the axis is, for example, an oval shape, and the anti-rotation hole 22f is also an oval shape that matches the piston rod 14 ( The size is slightly larger than the cross section of the piston rod 14 so that the piston rod 14 can reciprocate in the axial direction A), and the rod packing 15 has an annular shape in close contact with the piston rod 14. It should be noted that the hole in the wall 1 of the vacuum chamber through which the piston rod 14 of FIG. 6 passes does not have to be an oval shape that matches the piston rod 14.
[0005]
As described above, since not only the function of preventing air leakage into the vacuum chamber but also the function of preventing rotation of the piston rod 14 is applied to the front part 22b of the cylinder, the rod packing 15 provided on the front part 22b of the cylinder has a cross-sectional oval shape. In order to be in close contact with the piston rod 14, the shape is not an annular shape but an angular shape.
[0006]
[Problems to be solved by the invention]
However, while the inside of the vacuum chamber is vacuum or almost atmospheric pressure (in a helium atmosphere), the pressure of air supplied to the cylinder ports 22d and 22e is 4 to 5 kgf / cm ² (about 4 to 5) in terms of gauge pressure. Therefore, the rod packing 15 having an angular shape is insufficiently in close contact with the piston rod 14 and sufficiently prevents the air supplied to the port 22d at the front of the cylinder from leaking into the vacuum chamber. The result of X-ray fluorescence analysis could not be stabilized and could not be sufficiently accurate. There is a similar problem even if the cross-sectional shape of the piston rod 14 is a hexagon.
[0007]
The present invention has been made in view of such problems. In a pneumatic cylinder directly attached to the outer wall of a vacuum chamber of a fluorescent X-ray analyzer , the piston rod does not rotate around its axis, and the vacuum cylinder enters the vacuum chamber. It is an object of the present invention to provide an apparatus capable of sufficiently preventing air leakage, and a fluorescent X-ray analyzer capable of performing sufficiently accurate analysis using the apparatus.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the pneumatic cylinder for a vacuum chamber according to the first aspect of the present invention is used in a vacuum chamber of a fluorescent X-ray analyzer , and has a cylindrical shape and covers in front and rear in the axial direction. The cylinder is mounted so that the front surface is in close contact with the outer wall of the vacuum chamber, and the pressure of air supplied to the ports provided at the front and rear of the cylinder is reciprocated in the axial direction within the cylinder. And a piston to perform. Further, a rod-shaped piston rod that penetrates the wall of the vacuum chamber and the front portion of the cylinder and is fixed to the piston so that the tip portion reciprocates in the axial direction in the vacuum chamber; and the front of the cylinder Provided with a rod packing through which a cylindrical portion of the piston rod penetrates closely. Further, when the piston rod is inserted, an anti-rotation hole for preventing the piston rod from rotating about its axis is provided in the rear portion of the cylinder, and a port provided in the rear portion of the cylinder is provided with the anti-rotation device. It is located in front of the hole.
[0009]
In the pneumatic cylinder for vacuum chamber of the first invention of the present application, the function of preventing rotation of the piston rod is provided at the rear part of the cylinder and the function of preventing air leakage into the vacuum chamber is provided at the front part of the cylinder. Since the rod packing to be provided has an annular shape sufficiently close to the circular section of the piston rod, it is possible to sufficiently prevent the air supplied to the front port of the cylinder from leaking into the vacuum chamber. That is, in the pneumatic cylinder directly attached to the outer wall of the vacuum chamber of the fluorescent X-ray analyzer , the piston rod does not rotate around the axis, and air leakage into the vacuum chamber can be sufficiently prevented.
[0010]
The pneumatic cylinder for a vacuum chamber according to the second invention of the present application is also used for a vacuum chamber of a fluorescent X-ray analyzer . First, the cylinder has a cover in front and rear in the axial direction, and the front surface is the outer wall of the vacuum chamber. The cylinder is mounted so as to be in close contact with the cylinder, and the elastic force of the coil spring provided in the cylinder and the pressure of the air supplied to the port provided at the rear of the cylinder reciprocate in the cylinder in the axial direction. And a piston. Further, a rod-shaped piston rod that penetrates the wall of the vacuum chamber and the front portion of the cylinder and is fixed to the piston so that the tip portion reciprocates in the axial direction in the vacuum chamber; and the front of the cylinder A rod packing through which the piston rod penetrates closely. Further, when the piston rod is inserted, an anti-rotation hole for preventing the piston rod from rotating about its axis is provided in the front portion of the cylinder, and the inside of the cylinder communicates with the atmosphere at the front portion of the cylinder. A hole is provided.
[0011]
In the pneumatic cylinder for a vacuum chamber according to the second invention of the present application, it is a coil spring that moves the piston backward, and high pressure air is not supplied to the front part of the cylinder and is at most atmospheric pressure. Even if the rod packing provided in the portion has an angular shape corresponding to the piston rod rotation prevention, air leakage into the vacuum chamber can be sufficiently prevented. That is, in the pneumatic cylinder directly attached to the outer wall of the vacuum chamber of the fluorescent X-ray analyzer , the piston rod does not rotate around the axis, and air leakage into the vacuum chamber can be sufficiently prevented.
[0012]
The X-ray fluorescence analyzer of the third invention of the present application includes a vacuum chamber and uses the pneumatic cylinder for a vacuum chamber of the first or second invention of the present application. According to this X-ray fluorescence analyzer, since the vacuum chamber pneumatic cylinder according to the first or second invention of the present application is used in the vacuum chamber, air leakage into the vacuum chamber can be sufficiently prevented, and X-ray fluorescence can be prevented. The result of the analysis is sufficiently stable and accurate.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a pneumatic cylinder for a vacuum chamber according to a first embodiment of the present invention will be described with reference to the drawings. This pneumatic cylinder 7 is used in a vacuum chamber of a fluorescent X-ray analyzer , and as shown in the right side sectional view of FIG. A cylinder 2 attached so that the front surface 2a is in close contact with the outer wall 1a of the vacuum chamber, and a piston rod 4 to be described later are fixed, and air supplied to ports 2d and 2e provided at the front part 2b and the rear part 2c of the cylinder 2 And a piston 3 that reciprocates in the axial direction A in the cylinder 2 by the pressure of. The cylinder 2 is composed of a cylindrical cylinder tube and a cover attached to the front and rear in the axial direction A so as to close the opening thereof, but is illustrated here integrally. The front cover constitutes a front portion 2b of the cylinder 2, and the rear cover constitutes a rear portion 2c of the cylinder 2. The principle of the reciprocating movement of the piston 3 is the same as that described in the prior art.
[0014]
The rod-like piston rod 4 provided in the pneumatic cylinder 7 has a front portion penetrating the vacuum chamber wall 1a and the front portion 2b of the cylinder and a rear portion fixed to the piston 3, so that the front end portion 4a is inside the vacuum chamber. Reciprocate in the axial direction A. A rod packing 5 through which a cylindrical portion of the piston rod 4 penetrates closely is provided at the front portion 2b of the cylinder. Furthermore, a rotation stop hole 2 f that prevents rotation of the piston rod 4 around the axis by inserting the rear end portion 4 b of the piston rod 4 is provided in the rear portion 2 c of the cylinder.
[0015]
That is, the rear end portion 4b of the piston rod is not formed in a columnar shape, and the cross section perpendicular to the axis is, for example, an oval shape as shown in the rear view of FIG. An oval shape (the size is slightly larger than the cross section of the rear end portion 4b of the piston rod so that the piston rod 4 can reciprocate in the axial direction A) matches the portion 4b. As for the other part of the piston rod 4, as shown in the front view of FIG. 2, the tip 4a is provided with a damping plate or the like except that the cross section perpendicular to the axis is semicircular, for example. The rod packing 5 has an annular shape that is in close contact with the cylindrical portion of the piston rod 4. The cross-sectional shape of the rear end portion 4b of the piston rod and the shape of the anti-rotation hole 2f may be a hexagon or the like.
[0016]
As described above, in the vacuum chamber pneumatic cylinder 7 of the first embodiment, the piston rod rotation prevention function is provided to the rear part 2c of the cylinder, and the function of preventing air leakage into the vacuum chamber is provided to the front part 2a of the cylinder. For this reason, the rod packing 5 provided in the front part 2a of the cylinder has an annular shape that is sufficiently in close contact with the circular section of the piston rod 4, so that the air supplied to the port 2d at the front part of the cylinder is in the vacuum chamber. Leakage can be sufficiently prevented. That is, in the pneumatic cylinder directly attached to the outer wall 1a of the vacuum chamber of the fluorescent X-ray analyzer , the piston rod 4 does not rotate around the axis, and air leakage into the vacuum chamber can be sufficiently prevented.
[0017]
Next, a vacuum chamber pneumatic cylinder according to a second embodiment of the present invention will be described. This pneumatic cylinder 17 is also used in the vacuum chamber of the fluorescent X-ray analyzer , and as shown in the right side sectional view of FIG. A cylinder 12 attached so that 12a is in close contact with the outer wall 1a of the vacuum chamber, and a piston rod 14 to be described later are fixed. The elasticity of the coil spring 6 provided in the cylinder 12 and the port 12e provided in the rear portion 12c of the cylinder 12 And a piston 3 that reciprocates in the axial direction A in the cylinder 12 by the pressure of the air supplied to the cylinder 12. The cylinder 12 includes a cylindrical cylinder tube and a cover attached to the front and rear in the axial direction A so as to close the opening thereof, but is illustrated here integrally. The front cover constitutes a front portion 12b of the cylinder 12, and the rear cover constitutes a rear portion 12c of the cylinder 12.
[0018]
The principle of the reciprocating movement of the piston 3 is as follows, unlike the conventional technique and the first embodiment. That is, the coil spring 6 in which the front end portion is fitted in the recess provided in the front portion 12b of the cylinder urges the piston 3 rearward at the rear end portion (the state shown in FIG. 4). When air is supplied to the rear port 12e, the piston 3 is pushed forward by air pressure and moves. When the supply of air to the rear port 12e of the cylinder is stopped, the piston 3 is elastic (extension) of the coil spring 6. Force) to move backward. In the vacuum chamber pneumatic cylinder 17 of the second embodiment, the air for moving the piston 3 is not supplied to the port 12g provided in the front portion 12b of the cylinder, but simply for communicating the inside of the cylinder 12 with the atmosphere. It is a hole.
[0019]
The rod-like piston rod 14 provided in the pneumatic cylinder 17 is the same as described in the prior art, and the front part passes through the hole in the vacuum chamber wall 1a and the hole 12f in the front part 12b of the cylinder, and the rear part. When the end portion is fixed to the piston 3, the tip end portion 14a reciprocates in the axial direction A in the vacuum chamber. A rod packing 15 through which the piston rod 14 penetrates closely is provided at the front portion 12b of the cylinder. Further, the hole 12f in the front portion 12b of the cylinder is a non-rotating hole 12f that prevents the piston rod 14 from rotating about its axis when the piston rod 14 is inserted.
[0020]
That is, as described in the prior art, the piston rod 14 is not formed in a columnar shape, and as shown in the front view of FIG. Also, it is of an oval shape that matches the piston rod 14 (the size is slightly larger than the cross section of the piston rod 14 so that the piston rod 14 can reciprocate in the axial direction A). The ring is in close contact with the shape. The tip end portion 14a of the piston rod has, for example, a semi-oval type cross section perpendicular to the axis for mounting a damping plate or the like. The cross-sectional shape of the piston rod 14 and the shape of the anti-rotation hole 12f may be hexagonal or the like, and the rod packing 15 may be an annular shape in close contact with the piston rod 14.
[0021]
As described above, in the vacuum chamber pneumatic cylinder 17 of the second embodiment, it is the coil spring 6 that moves the piston 3 rearward, and high pressure air is not supplied to the front portion 12b of the cylinder. Because of the atmospheric pressure, even if the rod packing 15 provided on the front portion 12b of the cylinder has a corner-shaped profile corresponding to the rotation prevention of the piston rod 14, air leakage into the vacuum chamber can be sufficiently prevented. That is, in the pneumatic cylinder directly attached to the outer wall 1a of the vacuum chamber of the fluorescent X-ray analyzer , the piston rod 14 does not rotate around the axis, and air leakage into the vacuum chamber can be sufficiently prevented.
[0022]
Next, a fluorescent X-ray analyzer according to the third embodiment of the present invention will be described. First, the configuration will be described. As shown in FIG. 8, this apparatus includes a vacuum chamber 11 (vacuum chamber wall 1 and its internal space) that forms a vacuum or helium atmosphere, and the vacuum chamber pneumatic cylinder 7 of the first or second embodiment. , 17 is a fluorescent X-ray analyzer. Specifically, first, in the vacuum chamber 11, at least a tip portion of the X-ray tube 31, a sample stage 32, a spectroscopic element 33, and a detector 34 are provided.
[0023]
Further, in order to advance and retract the comb-like attenuation plate 35 for attenuating excess X-rays 39 to the detector 34 immediately before the detector 34, the vacuum chamber pneumatic cylinders 7 and 17 of the first or second embodiment are used. Are directly attached to the outer wall 1a of the vacuum chamber. That is, the front surfaces 2a and 12a of the pneumatic cylinders 7 and 17 are attached so as to be in close contact with the outer wall 1a of the vacuum chamber, and in the vacuum chamber 11, the tip portions 4a and 14a of the piston rod and the damping plate 35 attached thereto. Is reciprocated in the axial direction A of the cylinder (perpendicular to the X-ray optical path from the spectroscopic element 33 to the detector 34). FIG. 8 shows a state in which the attenuation plate 35 has advanced just before the detector 34. The attenuation plate 35 may be moved back and forth in the X-ray optical path between the spectroscopic element 33 and the detector 34 except for just before the detector 34, and between the X-ray tube 31 and the sample 36, You may make it advance / retreat to / from the spectroscopic element 33 in the X-ray optical path. Further, not only the attenuation plate 35 but also the pneumatic cylinders 7 and 17 may be used to advance or retract the filter in the X-ray optical path, or to selectively advance one of the plurality of spectral elements to the X-ray optical path. Good.
[0024]
Next, the operation of this apparatus will be described. A vacuum or helium atmosphere is formed in the vacuum chamber 11, the sample 36 placed on the sample stage 32 is irradiated with primary X-rays 37 from the X-ray tube 31, and the fluorescent X-rays 38 generated from the sample 36 are dispersed into the spectroscopic element. Spectroscopy at 33 to obtain a fluorescent X-ray 39 having a wavelength to be measured. Here, when it is considered that the spectroscopic fluorescent X-ray 39 has an excessive intensity with respect to the detector 34, the attenuation plate 35 is advanced immediately before the detector 34 by the pneumatic cylinders 7 and 17. The fluorescent X-rays 40 whose intensity has been appropriately attenuated by the attenuation plate 35 are made incident on the detector 34 and the intensity thereof is measured. The intensity of the original fluorescent X-ray 39 is calculated based on the attenuation ratio of the attenuation plate 35. When the spectroscopic fluorescent X-ray 39 is considered to have an appropriate intensity with respect to the detector 34, the attenuation plate 35 is retracted from immediately before the detector 34 by the pneumatic cylinders 7 and 17, and the spectroscopic fluorescent X The line 39 is directly incident on the detector 34 and its intensity is measured.
[0025]
Now, if there is an air leak into the vacuum chamber 11, the intensity of the measured fluorescent X-rays 39 and 40 gradually decreases, but the effect is measured as a vacuum atmosphere while pulling the inside of the vacuum chamber 11 with a vacuum pump. In the case of measuring as a helium atmosphere while injecting helium into the vacuum chamber 11, it is more likely to appear. Therefore, the inside of the vacuum chamber 11 is helium atmosphere, and the conventional pneumatic cylinder 27 (FIG. 6) is used for comparison in addition to the vacuum chamber pneumatic cylinders 7 and 17 of the first and second embodiments. In the case of the above, the first and second implementations are carried out by reciprocating the piston rod tips 4a and 14a with the damping plate 35 removed, and examining the gradient at which the measured intensity of the fluorescent X-ray 39 decreases with time. Even when the vacuum chamber pneumatic cylinders 7 and 17 of the form were used, it was about one third of that when the conventional pneumatic cylinder 27 was used.
[0026]
As described above, it is verified that the vacuum chamber pneumatic cylinders 7 and 17 of the first and second embodiments have less air leakage into the vacuum chamber 11 of the X-ray fluorescence analyzer than the conventional pneumatic cylinder 27. It was done. Therefore, according to the X-ray fluorescence spectrometer of the third embodiment using the vacuum chamber pneumatic cylinders 7 and 17 of the first and second embodiments for the vacuum chamber 11, air leakage into the vacuum chamber 11 is sufficiently prevented. The result of X-ray fluorescence analysis is sufficiently stable and accurate .
[0027]
【The invention's effect】
As described above in detail, according to the pneumatic cylinder for a vacuum chamber of the present invention, it can be directly attached to the outer wall of the vacuum chamber of the fluorescent X-ray analyzer , the piston rod does not rotate around the axis, and the vacuum chamber Air leakage into the chamber can be sufficiently prevented. Further, according to the fluorescent X-ray analysis apparatus of the present invention, since the vacuum chamber pneumatic cylinder of the present invention is used in the vacuum chamber, air leakage into the vacuum chamber can be sufficiently prevented, and the fluorescent X-ray analysis can be performed. The result is sufficiently stable and accurate.
[Brief description of the drawings]
FIG. 1 is a right side sectional view showing a vacuum chamber pneumatic cylinder according to a first embodiment of the present invention.
FIG. 2 is a front view showing the pneumatic cylinder.
FIG. 3 is a rear view showing the pneumatic cylinder.
FIG. 4 is a right side cross-sectional view showing a vacuum chamber pneumatic cylinder according to a second embodiment of the present invention.
FIG. 5 is a front view showing the pneumatic cylinder.
FIG. 6 is a right side sectional view showing an example of a conventional pneumatic cylinder.
FIG. 7 is a front view showing the pneumatic cylinder.
FIG. 8 is a schematic view showing a fluorescent X-ray analyzer according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber wall, 1a ... Vacuum chamber outer wall, 2, 12 ... Cylinder, 2a, 12a ... Front of cylinder, 2b, 12b ... Front of cylinder, 2c, 12c ... Rear of cylinder, 2d ... Front of cylinder Air supply port provided at the part, 2e, 12e ... Air supply port provided at the rear part of the cylinder, 2f, 12f ... Anti-rotation hole, 3 ... Piston, 4, 14 ... Piston rod, 4a, 14a ... Piston rod Tip portion, 5, 15 ... Rod packing, 6 ... Coil spring, 7, 17 ... Vacuum cylinder pneumatic cylinder, 11 ... Vacuum chamber, A ... Axial direction of cylinder.

Claims (3)

A pneumatic cylinder used in a vacuum chamber of an X-ray fluorescence analyzer ,
A cylinder having a cover in front and back in the axial direction and attached so that the front surface is in close contact with the outer wall of the vacuum chamber;
A piston that reciprocates in the cylinder in the axial direction by the pressure of air supplied to ports provided at the front and rear of the cylinder;
A rod-shaped piston rod that penetrates the wall of the vacuum chamber and the front part of the cylinder and is fixed to the piston, so that the tip portion reciprocates in the axial direction in the vacuum chamber;
A rod packing provided at a front portion of the cylinder, through which a cylindrical portion of the piston rod closely passes,
When the piston rod is inserted, an anti-rotation hole for preventing rotation of the piston rod about its axis is provided at the rear portion of the cylinder.
A vacuum cylinder for a vacuum chamber, wherein a port provided at a rear portion of the cylinder is positioned in front of the rotation stop hole. A pneumatic cylinder used in a vacuum chamber of an X-ray fluorescence analyzer ,
A cylinder having a cover in front and back in the axial direction and attached so that the front surface is in close contact with the outer wall of the vacuum chamber;
A piston that reciprocates in the axial direction in the cylinder by the elasticity of a coil spring provided in the cylinder and the pressure of air supplied to a port provided in the rear part of the cylinder;
A rod-shaped piston rod that penetrates the wall of the vacuum chamber and the front part of the cylinder and is fixed to the piston, so that the tip portion reciprocates in the axial direction in the vacuum chamber;
A rod packing provided at a front portion of the cylinder, and through which the piston rod penetrates closely;
When the piston rod is inserted, an anti-rotation hole that prevents rotation of the piston rod about its axis is provided in the front portion of the cylinder,
A pneumatic cylinder for a vacuum chamber, wherein a hole for communicating the inside of the cylinder with the atmosphere is provided at a front portion of the cylinder. A fluorescent X-ray analysis apparatus comprising a vacuum chamber and the vacuum chamber pneumatic cylinder according to claim 1.

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