JP2880520B2 - Water column nozzle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water column nozzle, and more particularly, to a water column nozzle, which is attached to a probe (sensor) and measures the size of an object to be measured by an ultrasonic pulse echo method, for example, a plate thickness. It is used for a device for automatically measuring the size of a sample, a device for flaw detection of an internal defect of an object to be measured, and the like.

2. Description of the Related Art Conventionally, as shown in FIG. 9, a dimension measuring device of this type of ultrasonic pulse echo method has a nozzle 2 attached to a tip of an ultrasonic probe (hereinafter, referred to as a probe) 1. Ultrasonic waves oscillated from the probe 1 with respect to the DUT 3 are propagated in a water column 4 jetted from the nozzle 2 so that the DUT 3
Incident on A part of the ultrasonic wave incident on the DUT 3 is reflected from the surface of the DUT as a surface echo El, while the ultrasonic wave entering the DUT is reflected as a back echo E2 on the back surface. The thickness of the object to be measured is measured by the time interval between the reflection echoes El and E2.

As the water column nozzle 2 used in this type of measuring apparatus, those having the structure shown in FIGS. 10 and 11 have been conventionally provided. In each case, the tip of the probe 1 is concentric with the probe. The cylindrical nozzle housing 5 is attached by the above, and the inner cylinder 6 is attached concentrically inside the housing 5 with a gap. A tip of the inner cylinder 6 (the tip of the housing 5 connected to the inner cylinder 6 in the conventional example shown in FIG. 11) is used as a water outlet 7 and a water supply port 8 is provided on a peripheral wall of the housing 5. The water supplied from the water supply port 8 passes through an equalizing chamber 9 formed between the inner wall of the housing 5 and the outer wall of the inner cylinder 6 and passes through an orifice-shaped turnback portion 10 as shown by an arrow. After the surface of the touch element 1 is brought into contact with the lick, it flows forward in the inner cylinder 6 and is jetted from the water outlet 7. Incidentally, in the conventional example shown in FIG.
A flow straightening plate 11 is interposed in the flow path toward, and a restrictor 7a is formed in the portion of the water outlet 7 in the conventional example shown in FIG.

In this type of water column nozzle, FIG. 10 and FIG.
As shown in Fig. 11, in either structure, after the water flowing from the water supply port was once equalized in the pressure equalizing chamber, a flow toward the probe was formed, and then turned back to search. There is a need to have a configuration in which a jet is made to come out from a water outlet after being brought into contact with the surface of the probe to remove bubbles and dust adhering to the surface of the probe.

Problems to be Solved by the Invention When performing the dimension measurement by the ultrasonic pulse echo method, a water column jetted from the nozzle to the material to be measured,
That the pressure is uniform and stable over the circumference,
This is necessary from the point of measurement accuracy, and in order to make the pressure uniform, it is necessary to surely prevent air bubbles from entering the water column. However, the above-mentioned conventional nozzle has a problem that air bubbles cannot be reliably removed.

Furthermore, in general, the material to be measured is on a predetermined line, and the probe of the measuring device is also installed at a predetermined position. Therefore, the distance between the probe and the material to be measured is usually set to a fixed distance. It is specified (indicated by an interval W in FIG. 9). The measurement accuracy is more stable and improved as the water column comes into contact with the material to be measured at a greater distance than the water column contacts the material to be measured at a position close to the nozzle outlet. I can do it. However, in the above-mentioned conventional nozzle, in order to obtain a stable water column, the so-called so-called approach distance is increased, and the axial dimension of the nozzle is increased.
Therefore, there is a problem that a long distance cannot be provided between the water outlet of the nozzle and the material to be measured. For example, when the distance between the probe and the material to be measured is specified to be 38 mm, the distance between the nozzle water outlet and the material to be measured can be only 5 mm with the conventional nozzle. In addition, when it is required to keep a distance due to the presence of some kind of inclusion between the material to be measured and the tip of the nozzle, the axial dimension of the nozzle itself is short, and the water column is stable and far away. Although it is preferable to fly to the above, in the above-mentioned conventional nozzle,
This requirement cannot be met.

Further, as a pressure equalizing chamber provided on the outer periphery of the probe, Japanese Utility Model Application Laid-Open No. 60-46065, Japanese Utility Model Application No. 60-72562, and Japanese Utility Model Application Laid-Open No. 60-72563 have been proposed. In each of these cases, the water flow flowing along the outer periphery of the probe generates a vortex at the periphery of the front surface of the probe, so that it is difficult to form a long and stable water column, and there is a problem that air bubbles easily accumulate. was there.

The present invention has been made in view of the above problems, and has no entrainment of air bubbles, uniform pressure in the circumferential direction, a stable water column can be obtained without generating a twist, and the stable water column is far away. It is an object of the present invention to provide a water column nozzle that can fly to a distance and that can shorten the axial length of the nozzle itself.

Means for Solving the Problems In order to achieve the above object, the present invention relates to a nozzle which is mounted on an ultrasonic probe to form a water column as a contact medium, and has a cylinder coaxial with the ultrasonic probe. A nozzle part formed of a partition wall in a shape of a circle and forming a water column on the front surface of the ultrasonic probe,
A pressure equalizing chamber formed on the outer periphery of the nozzle portion and provided with a water suction port communicates with the pressure equalizing chamber and the ultrasonic probe front side of the nozzle portion, and is coaxial with the ultrasonic probe and the nozzle portion. An annular water guiding portion provided on the partition wall portion, the water guiding portion extending from a rear end of the partition wall portion in a circumferential direction to a rear surface of the protruding portion, and an extending portion extending outward from a front surface of the ultrasonic probe. And by arranging it in parallel with a slight gap with the front surface of the ultrasonic probe, the direction of the water flow introduced into the front surface of the ultrasonic probe is inclined in a direction orthogonal or opposite to the outflow direction of the water column. It is a thing.

The underwater nozzle includes two members, a front member and a rear member, which are assembled coaxially with each other, the front member includes a front wall portion of the nozzle portion and the water guiding portion, and the rear member includes an ultrasonic probe holding portion. It is preferable to provide a configuration including a rear wall portion of the water guide section.

Action The present invention provides an annular water guide provided coaxially with the ultrasonic probe and the nozzle, communicating the pressure equalizing chamber with the front side of the ultrasonic probe of the nozzle, and detecting the water from the water guide. Since it is made to flow from the entire circumference to the front edge of the probe at an angle that is orthogonal or opposite to the direction of the water column, no vortex is generated on the front surface of the probe, and the nozzle portion is circumferentially A water stream having a uniform pressure can be obtained, and a long and stable water column can be obtained in the water stream injected from the water outlet of the nozzle.

In addition, since the axial length of the pressure equalizing chamber can be shortened and the cross-sectional area can be increased, the overall shape of the nozzle becomes shorter in the axial direction,
The distance between the water outlet of the nozzle and the material to be measured can be made longer than in the past.

Examples Hereinafter, the present invention will be described in detail with reference to examples shown in the drawings.

In the first embodiment shown in FIGS. 1 (A), 1 (B) and 1 (C), 1 is a probe, 12 is a nozzle upper fitting, 13 is a nozzle lower fitting, and the nozzle upper fitting 12 and the lower fitting 13 are combined. A water column nozzle housing that is assembled to the probe 1 in combination is configured.

In FIG. 1, a water outlet 16 to be described later is directed downward, so that 12 is a nozzle upper bracket and 13 is a nozzle lower bracket. Can be used towards the side. Therefore, “upper” and “lower” are used for the purpose of explanation only, the nozzle lower bracket 13 constitutes a member (front member) in the jetting direction (front) of the water column, and the nozzle upper bracket 12 forms the member of the water column. It constitutes a member (rear member) in the direction (rear) opposite to the ejection direction.

The nozzle upper fitting 12 includes a probe mounting cylindrical portion 12a having upper and lower end openings to which the probe 1 is fitted, a conical portion 12b inclined downward from the lower end of the cylindrical portion 12a toward the outside and lower, and It has a structure in which a large-diameter pressure equalizing chamber forming cylindrical portion 12c bent downward from the outer end of the conical portion 12b is integrally formed. The conical portion 12b has a water supply port 14 formed therein.
Is connected to a water supply connector 15. In this embodiment, the inclination angle of the conical portion 12b is α1 = 30 °. Further, a screw for screw fitting is formed on the outer peripheral surface of the cylindrical portion 12c.

On the other hand, the nozzle lower bracket 13 is formed at the center of the cylindrical portion 13a that fits over the cylindrical portion 12c of the nozzle upper bracket 12, a bottom portion 13b that closes the lower end surface of the cylindrical portion 13a, and a center portion of the bottom portion 13b. It has a structure in which a substantially conical cylindrical partition wall portion 13c protruding upward from the outer peripheral portion of the water outlet 16 is integrally formed. The partition wall portion 13c has a nozzle portion 1 communicating with a water outlet 16 in a hollow portion thereof.
Forming 7 The shape of the partition wall portion 13c is a shape having a projecting portion 13d in the outer peripheral direction, and more specifically, an inclined surface 13d-2 inclined upward and outward from the bottom surface portion 13b, and the inclined surface 13d-2.
In this embodiment, the angle of the inclined surface 13d-2 is α2.
= 60 °, the angle of the inclined surface 13d-1 is the same as the angle α1 of the nozzle upper bracket 12, and the angle α3 is set to 30 °. Also,
The nozzle part 17 is tapered toward the water outlet 16,
The upper end is set to φ10, and the lower end is set to φ6.

FIG. 1 (A) shows the nozzle upper fitting 12 and the lower fitting 13.
As shown in the figure, the cylindrical portions 12c and 13a are screwed together and assembled, and the cylindrical portion 12a of the upper metal fitting 12 is attached to the probe 1 by an O-ring 1.
The nozzle housing is formed by fitting through the fitting 8 and the mounting bracket 19 and assembled. In the assembled state, the end face of the probe 1 is arranged so as to be exposed at the axial center of the upper end face of the housing, and the nozzle portion is located at a position facing the end face of the probe.
A water outlet 16 is located via 17. Nozzle lower bracket 13
The upper inclined surface 13d-1 of the protruding portion 13d of the partition wall portion 13c is arranged in parallel with the conical surface 12b of the upper fitting 12 with a slight gap therebetween, and forms an annular water guide portion 20. The upper end of the nozzle part 17 communicating with the inner peripheral part of the water guide part 20 is the probe 1 of the housing.
And is open facing the lower end surface of. In addition, the conical surface 12b and the cylindrical portion 12c of the upper fitting 12 and the cylindrical portion 13a and the bottom 1
3b, an annular pressure equalizing chamber 21 surrounded by the partition wall 13c is formed. The pressure equalizing chamber 21 has a large cross-sectional area at the bottom as shown in the drawing, and a gradually decreasing cross-sectional area toward the upper water-guiding section 20, and has an outer peripheral portion at the upper end communicating with the water-guiding section 20,
The overall shape is a large-capacity chamber that has a shorter axial length but a larger cross-section than a conventional pressure equalizing chamber of a nozzle.

In the present embodiment, the overall dimension is such that the length L from the lower end surface of the probe 1 to the water outlet 16 is 27.5 mm, and the diameter W of the lower end portion of the pressure equalizing chamber 21 is φ68 mm. Therefore, when the distance from the probe 1 to the workpiece 3 is 37.5 mm, the distance from the water outlet 16 of the nozzle to the workpiece 3 can be set to 10 mm. In addition, it is preferable that the flow path length B of the water guide section 20 is as large as possible, but in the present embodiment, it is set to 10 mm. As described above, the size of the nozzle portion 17 is φ at the upper end portion.
10, φ6 at exit at lower end. Therefore, the diameter of the outer peripheral portion (inlet) of the water guide section 20 is set to be twice or more the diameter of the inner peripheral portion (outlet). Further, the gap between the water guide sections 20 is shown in FIG.
As shown in (1), it is preferable that the length is not more than one fifth of the flow path length B.

Next, the operation of the nozzle will be described.Water supplied from a water supply port 14 provided in the conical portion 12b of the upper fitting 12 is
As shown by an arrow in FIG. 1 (A), the gas flows downward into the pressure equalizing chamber 21. Further, in the pressure equalizing chamber 21, the water flowing into the pressure equalizing chamber 21 is particularly large because the central partition wall portion 13c is inclined so as to increase the volume of the pressure equalizing chamber toward the lower end side. Flows into the pressure equalizing chamber 21 so as to collect on the bottom side. After the pressure equalizing chamber 21 is completely filled with water, the water is guided to an upper orifice-like water guide section 20 and then jetted from a water outlet 16 through a nozzle section 17. An amount commensurate with the injection amount is supplied from the water supply port 14, so that the pressure equalizing chamber 21 is always in a state of being completely filled with water.

In the above-mentioned nozzle, the equalizing chamber with a large cross-sectional area
In the inside 21, the pressure in the circumferential direction of the inflowing water becomes substantially uniform, and the water guide section having a small gap that is annular and has a relatively long flow path on the way from the equalizing chamber 21 to the nozzle section 17. By passing through 20, furthermore, the circumferential pressure of the water becomes uniform. Therefore, water flows into the nozzle portion 17 at a uniform pressure in the circumferential direction, and a water column sprayed from the water outlet 16 toward the material 3 to be measured is formed into a long and stable water column at a uniform circumferential pressure. You can do it. In addition, as described above, since the pressure in the circumferential direction is uniform and the pressure equalizing chamber 21 is always filled with water, bubbles are hardly generated, and the entrapment of bubbles is prevented. Can be done.

As described above, since a stable water column can be formed long, even when the distance from the water outlet 16 of the nozzle to the material 3 to be measured is twice as long as that of the conventional nozzle, the measurement result with high accuracy can be obtained. Can be obtained.

2, 3 and 4 show experimental data of the nozzle according to the present invention. The nozzle of the present invention uses the embodiment shown in FIG. 1, and the fluid has a specific weight of 998.2 kg / m ³ , a kinematic viscosity coefficient of 1.010 × 10 ⁻⁶ m ³ / S, and an inflow velocity of 0.7 m / m. S is used.

FIGS. 2A and 2B show comparison data between the case where the nozzle of the present invention is used and the case where the conventional nozzle shown in FIG. 10 is used.

In this experiment, the distance from the water outlet to the material to be measured was 15 mm, and the fluctuation of the height of the reflected echo was examined. FIG. 2 (A) shows the case where the above-mentioned nozzle of the present invention is used, and the fluctuation is
In the range of 4.5 to 5.2 V, almost no whisker-like noise is generated. On the other hand, FIG. 2 (B) shows a case where a conventional nozzle is used. The fluctuation is large in the range of 4 to 6 V, and many whisker-like noises are generated.

FIGS. 3 and 4 are diagrams in which a computer simulates a vector diagram of the water flow in the nozzle according to the present invention. FIG. 3 shows the vector of the water flow in the cross section of each part of the nozzle, and FIG.
And the upper end of the nozzle portion 17 (a portion facing the probe 1 and 27.5 mm above the water outlet 16), FIG. 3 (B) is a middle portion of the nozzle (13.75 mm above the water outlet), FIG. C) is a cross-sectional view of a portion near the water outlet (5.5 m above the water outlet).

Each cross section shows the half side of 0 to 180 °, and 10
Although the water flow vector is expressed every degree, in the figure, at the left end corresponding to the water supply port, the water flow vector is subdivided every 6 °. Points or lines indicate the flow velocity, the flow velocity increases according to the length of the line,
The arrows attached to the lines indicate the flow direction.

As shown in FIG. 3 (A) -I and a partially enlarged view of FIG. 3 (A) -II, the water flow vector at the upper end of the nozzle portion 17 is uniform and smooth throughout the circumferential direction. And the direction is also toward the center of the nozzle portion 17. In FIG. 3 (C), that is, the flow velocity distribution in the equalizing chamber 5.5 mm above the water outlet 16 is affected by the inflow from the water supply port 14, and a circumferential component remains. However, in the pressure distribution in the pressure equalizing chamber 8.25 mm above (C), that is, in FIG. 3 (B), the pressure is considerably equalized, and the circumferential component is considerably small. Fig. 3 (A)
As shown in the figure, all are directed to the center, and there is almost no circumferential component causing rotation.

FIG. 4 is a simulation of a longitudinal section of the nozzle,
It has been proved that the water is in a pressure equalized state throughout the pressure equalizing chamber 21.

The present invention is not limited to the structure shown in FIG. 1, but may be a structure shown in FIGS. The modified examples shown in FIG. 5 to FIG.
And the nozzle lower bracket 13 'form a cylindrical nozzle housing having a diameter larger than the axial length.

First, in the modification shown in FIG. 5, the shape of the partition wall 30 of the nozzle lower bracket 13 'is modified as shown in FIG.
A portion 31b 'protruding from the central water outlet 16' is formed in a cylindrical shape, and an inclined protruding portion 32 protruding largely outward is provided at an upper end thereof. The upper surface 32a of the projecting portion 32 is parallel to the inclined surface 33 of the upper metal fitting 12 'to form a water guiding portion 20' having a long distance B, and a large capacity equalizing chamber 21 'below the projecting portion 32. Is formed. The inclination of the upper surface 32a of the protrusion 32 is for facilitating the removal of air bubbles, and the inclination of the lower surface 32b of the protrusion 32 is for facilitating the removal of air bubbles and acoustic noise. The reason for this is that by making the shape close to the curved surface of the lens, a smooth streamline is obtained and no air bubbles adhere to the acoustic lens surface. Further, a space is provided on the outer wall of the
A water inlet 15 'is provided at each location. Providing a plurality of water inlets at intervals can reduce the influence of disturbance at the water inlets on the whole.

The modification shown in FIG. 6 is a projection of the modification shown in FIG.
32 is not inclined, but protrudes in a direction perpendicular to the axis. With this structure, there is an advantage that processing can be performed easily and inexpensively.

In the modification shown in FIG. 7, the water outlet 16 'is directed upward,
It can be suitably used when forming a water column upward. That is, the bottom portion 13b 'of the nozzle lower bracket 13'
Further, as shown in the figure, the partition wall portion 40 is formed so as to incline in a mountain shape with the center water outlet 16 'as a center and protrude upward. The central shaft hole of the partition wall portion 40 is a nozzle portion 17 ', and the nozzle portion 17' is tapered and tapered toward the water outlet. On the other hand, the above-mentioned partition wall
40, a parallel inclined projection 41 facing the inclined surface 40a is formed, a water guide 20 'is formed between the inclined portion 41 and the inclined surface 40a, and the water guide 20' is formed by the inclined projection 41. The pressure equalizing chamber 21 'is formed on the upper side which is partitioned.

FIG. 8 is also a modified example in which bubbles are easily removed when a water column is formed upward, and is preferably used. The inclined protruding portion 41 shown in FIG. 7 is modified so that the lower side is inclined as shown. At the same time, a partition wall part 50 protruding in the horizontal direction is provided on the upper side, and a water guide part forming part 51 protruding upward from an outer edge of the partition wall part 50 is attached. With the above configuration, the pressure equalizing chamber 21 ′
The length of the water guide section 20 'communicating with the nozzle section 17' is greatly increased.

Effect of the Invention As is clear from the above description, according to the water column nozzle of the present invention, in a pressure equalizing chamber having a large cross-sectional area,
The flow of the water supplied from the water supply port is substantially equalized in the circumferential direction, and the water is supplied from the equalizing chamber to the nozzle portion through the water guiding portion, and the water guiding portion has an annular shape and forms an orifice. Since the gap is so small and the flow path is long, it is possible to flow into the nozzle portion at a uniform pressure in the circumferential direction from the entire circumferential direction. Therefore,
In the nozzle section, uniform pressure in the circumferential direction is achieved,
It is possible to fly the water column jetted from the water outlet in a stable state and far away.

In addition, the nozzle of the present invention has a large cross-sectional area, a short axial length, and a longer length from the nozzle water outlet to the material to be measured as compared with the conventional nozzle. In addition to the ability to form a water column, it also has advantages such as improvement in the accuracy of the reflected echo.

[Brief description of the drawings]

1 (A) is a vertical sectional view showing an embodiment of a nozzle according to the present invention, FIG. 1 (B) is a sectional view of a nozzle upper fitting, FIG. 1 (C) is a sectional view of a nozzle lower fitting, 2 (A) and 2 (B) are diagrams comparing experimental data between the nozzle shown in FIG. 1 of the present invention and a conventional nozzle, and FIG. 3 (A).
-I, Fig. 3 (A) -II, Fig. 3 (B), Fig. 3 (C)
FIG. 4 is a drawing in which a computer simulates a vector diagram of a water flow in each cross section of the nozzle portion shown in FIG. 1 of the present invention, and FIG. 4 is a vertical sectional view of the nozzle shown in FIG. 1 of the present invention. 5, FIG. 6, FIG. 7, FIG. 7, and FIG. 8 are partial cross-sectional views showing a displacement example of the present invention, and FIG.
FIG. 1 is a drawing showing an ultrasonic pulse-echo type measuring device for showing an example of use of a nozzle according to the present invention, and FIGS. 10 and 11 are sectional views showing a conventional nozzle. 1… Probe, 12… Nozzle upper fitting, 12 a …… Probe cylindrical part, 12 b… Conical part, 12 c… Nozzle lower fitting cylindrical part, 13… Nozzle lower fitting, 13 a …… Cylindrical part, 13b …… Bottom part, 13c …… Partition wall part, 14 …… Water inlet,
16 ... water outlet, .17 ... nozzle, 20 ... water guide, 21 ...
... Equalizing chamber.

────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference Jikken 46-22559 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01B 17/00-17/04

Claims (2)

(57) [Claims] 1. A nozzle mounted on an ultrasonic probe to form a water column as a contact medium, the nozzle being formed by a cylindrical partition wall coaxial with the ultrasonic probe,
A nozzle portion that forms a water column on the front surface of the ultrasonic probe, a pressure equalizing chamber formed on the outer periphery of the nozzle portion and provided with a water suction port, and an ultrasonic probe front surface of the pressure equalizing chamber and the nozzle portion An annular water guiding portion provided coaxially with the ultrasonic probe and the nozzle portion, wherein the water guiding portion is a rear surface of a projecting portion that projects outward from a rear end of the partition wall portion. Are formed by arranging them in parallel with the front surface of the extension part extending outside the front surface of the ultrasonic probe with a slight gap, and the direction of the water flow introduced into the front surface of the ultrasonic probe. Is inclined in the direction orthogonal or opposite to the outflow direction of the water column. 2. The apparatus according to claim 1, further comprising: a front member and a rear member which are assembled coaxially with each other, wherein the front member includes the nozzle portion and a front wall portion of the water guide portion, and the rear member includes an ultrasonic probe holding portion. The water column nozzle according to claim 1, further comprising a rear wall portion of the water guiding section.