JPH02236408A - Water column nozzle - Google Patents

Abstract

PURPOSE:To obtain a stable water column, which entraps no air bubbles and has a uniform pressure in the peripheral direction, without twisting by flowing water from a pressure equalizing chamber having a large transectional area to a nozzle part through a conduit. CONSTITUTION:Water supplied from a water supply port 15 provided in an upper metallic conical part 12b flows downward into a pressure equalizing chamber 21. Since a central partitioning wall part 13c in the chamber 21 is inclined toward the lower end side so that the capacity of the chamber 21 is expanded, water flowing into the chamber 21 flows to stay on the bottom side. After the chamber 21 is completely filled up with water, water is led to conduit 20 like an orifice in the upper part and is sprayed from a water exit 16 through a nozzle part 17. The quantity of water corresponding to the quantity of sprayed water is supplied from the water supply port 15 to always completely fill up the chamber 21 with water.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water column nozzle, and more particularly, the present invention relates to a water column nozzle that is attached to a probe (sensor) and is used to measure the dimensions of an object to be measured, such as a plate, using an ultrasonic pulse/eco system. It is used in devices that automatically measure thickness dimensions and devices that detect internal defects in objects to be measured.

BACKGROUND OF THE INVENTION Conventionally, as shown in FIG. 9, this type of ultrasonic pulse/eco one-type dimension measuring device has a nozzle 2 attached to the tip of a probe 1, and a probe for an object 3 to be measured. Ultrasonic waves emitted from the probe 1 are propagated in a water column 4 ejected from a nozzle 2 and are incident on the object 3 to be measured. A part of the ultrasonic waves incident on the object to be measured 3 is a surface echo E! from the surface of the object to be measured. On the other hand, the ultrasonic waves that entered the object to be measured are reflected on the back surface as back surface echoes E2, and these reflected echoes E! The plate thickness of the object to be measured is measured at the time intervals of E2 and E2.

Conventionally, the water column nozzle 2 used in this type of measuring device has the structure shown in FIGS. A cylindrical nozzle housing 5 is attached, and an inner cylinder 6 is attached concentrically within the housing 5 with a gap. The tip of the inner cylinder 6 (in the conventional example shown in FIG. 11, the inner cylinder 6
A water outlet 7 is provided at the end of the housing 5 connected to the housing 5, and a water supply port 8 is provided on the peripheral wall of the housing 5.

The water supplied from the water supply port 8 passes through a pressure 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 section as shown by the arrow. After passing through the inner cylinder 6 and making contact with the surface of the probe 1 in a licking manner,
The water flows inside towards the water and is sprayed from the water outlet 7. In the conventional example shown in FIG. 10, a rectifier plate l1 is interposed in the flow path from the pressure equalization chamber 9 toward the probe 1, and in the conventional example shown in FIG. Aperture 7
It forms a.

In this type of water column nozzle, as shown in Figs. 10 and 11 above, in any structure, the water flowing in from the water supply port is once equalized in pressure in the pressure equalization chamber, and then After forming a flow toward the surface of the probe, the water is turned back to contact the surface of the probe, and after removing air bubbles and dust adhering to the surface of the probe, the water is injected from the water outlet. is needed.

Problems to be Solved by the Invention When measuring dimensions using the above-mentioned ultrasonic pulse/eco method, the pressure of the water column sprayed from the nozzle onto the material to be measured is uniform and stable in the circumferential direction. This is necessary from the viewpoint of measurement accuracy, and in order to equalize this pressure, it is necessary to reliably prevent air bubbles from entering the water column. However, the conventional nozzle described above has a problem in that it is not possible to reliably eliminate the inclusion of air bubbles.

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, so the distance between the probe and the material to be measured is usually a constant distance. (Indicated by interval W in Figure 9)
. Measurement accuracy can be stabilized and improved by having a stable water column contact the material to be measured at a distance, rather than by having the water column contact the material to be measured at a position close to the nozzle outlet. I can do it. However, in the above-mentioned conventional nozzles, in order to obtain stable water flow, the axial dimension of the nozzle is increased to cover the so-called run-up distance. The problem was that it was not possible to leave a long distance between them. For example, when the distance between the probe and the material to be measured is specified as 38n+m, the distance between the nozzle water outlet and the material to be measured is 5 mmL, which cannot be achieved with the conventional nozzle mentioned above. . In addition, if it is required to create a distance between the material to be measured and the tip of the nozzle due to the presence of some kind of inclusion, the axial dimension of the nozzle itself can be shortened to keep the water column stable and far away. However, the conventional nozzles described above cannot meet this requirement.

The present invention has been made in view of the above problems, and it is possible to obtain a stable water column without entrainment of air bubbles, uniform pressure in the circumferential direction, and without twisting, and to extend the stable water column far away. It can fly a long distance, and
It is an object of the present invention to provide a water column nozzle 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 combines a nozzle upper metal fitting and a nozzle lower metal fitting to form a housing having a short axial length and a large cross-sectional area. The probe is attached to the nozzle upper fitting so that its tip surface is exposed at the upper axial center of the housing, while a water outlet is formed at the bottom axial center of the nozzle lower fitting opposite to the probe tip surface, and , a nozzle part that communicates with the water outlet and extends to the vicinity of the tip surface of the probe is formed by a cylindrical partition wall part protruding from the nozzle lower metal fitting; A large volume annular pressure equalizing chamber is formed between the protrusion and the inner surface of the lower wall of the nozzle upper fitting, and an annular water guide portion with a small gap is formed between the protrusion and the inner surface of the earthen wall. , the inner periphery of the water guide portion is communicated with the upper end of the nozzle portion facing the end face of the probe, the outer periphery is communicated with the pressure equalization chamber, and a water supply port is provided on the outer wall of the pressure equalization chamber. A water column nozzle, characterized in that the fluid that flows into the housing from the water supply port passes through the water guide section from the pressure equalization chamber, contacts the end face of the probe, flows into the nozzle section, and is injected from the water outlet. It provides:

Furthermore, in the present invention, a cylindrical part for attaching a probe is formed in the narrow part of the nozzle upper metal fitting, a protruding part is provided outwardly from the outer peripheral surface of the cylindrical part, and the protruding part and the nozzle lower metal fitting are connected to each other. The present invention provides a nozzle suitable for spraying a column of water upward, having a configuration in which a pressure equalizing chamber is formed between the inner surface of the earthen wall and a water guide section is formed between the inner surface of the lower wall and the inner surface of the lower wall.

As described above, the present invention is provided with a pressure equalization chamber having a short axial length and a large cross-sectional area, and a long annular flow with a small gap in the flow path from the pressure equalization chamber to the nozzle part. A water guide section is provided in the channel, and water flows from the water guide section to the nozzle section from the entire circumference, so that a water flow with uniform pressure in the circumferential direction is obtained at the nozzle section, and water flows from the water outlet of the nozzle to the nozzle section. It is possible to obtain a long and stable water column in the jetted water stream.

Furthermore, since the overall shape of the nozzle is shortened 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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to embodiments shown in the drawings.

In the first embodiment shown in FIG. 1 (AXBXC), 1 is a probe, ! 2 is a nozzle upper metal fitting; [3 is a nozzle lower metal fitting; the nozzle upper metal fitting 12 and the lower metal fitting 13 are combined to constitute a housing of a water column nozzle to be assembled to the probe I.

The nozzle upper metal fitting I2 includes a cylindrical part 12a for mounting a probe, which has openings on the upper and lower end faces into which the probe 1 is fitted, and a cylindrical part 12a for mounting the probe.
A conical part that slopes outward from the lower end of a! 2b and a large-diameter cylindrical portion 12c for forming a pressure equalization chamber, which is bent downward from the outer end of the conical portion 12b, are integrally formed. A water supply port l4 is provided in the conical portion 12b. 4 is connected to a water supply connector l5.

In this embodiment, the inclination angle of the conical portion +2b is α
The angle is 1-30°. Further, a thread for screwing is formed on the outer peripheral surface of the cylinder 12c.

On the other hand, the nozzle lower metal fitting! 3, a cylindrical portion 13a that fits onto the cylindrical tube L2c of the nozzle upper fitting l2; and the cylindrical portion 13a.
It has a structure in which a bottom surface portion 13b that closes the lower end surface of the bottom surface portion 13b and a partition wall portion 13c having a substantially conical cylindrical shape that projects upward from the outer circumference of the water outlet l6 formed at the center of the bottom surface portion 13b are integrally formed. . The partition wall portion 13c forms a nozzle g517 communicating with the water outlet l6 in its hollow portion. The shape of the partition wall portion 13c is a shape having a protruding portion 13d in the outer circumferential direction, specifically, an inclined surface 13d-1 inclined outward and upward from the bottom surface portion 13b, and an inclined surface 13d-1 inclined outward and upward from the upper end of the inclined surface 13dl. It has an inclined surface 13d2, and in this embodiment, the angle of the inclined surface 13dl is α2=60°,
The angle of the inclined surface 13d-2 is the angle α of the nozzle upper fitting l2.
The angle α3 is set to 30°. Further, the nozzle portion l7 is tapered toward the water outlet l6, and is set to φ10 at the upper end and φ6 at the lower end.

The nozzle upper metal fitting I2 and lower metal fitting I3 are shown in Fig. 1 (A
), the cylindrical parts 12c and 13a are screwed together and assembled, and the cylindrical part 12a of the upper fitting 12 is fitted to the probe I via the O-ring l8 and the mounting fitting 19 to assemble the nozzle housing. It is assembled to form. In the assembled deaf, the end face of the probe l is placed in an exposed state at the axial center of the upper end face of the housing, and the water outlet l6 is located at a position facing the end face of the probe via the nozzle part l7. are doing. The upper inclined surface 13d-2 of the protrusion 13d of the partition wall 13c of the lower nozzle fitting 13 is arranged parallel to the conical surface 12b of the upper fitting 12 with a slight gap, forming an annular water guiding section 20. . The upper end of the nozzle l7, which communicates with the inner peripheral part of the water guide part 20, is open to face the lower end surface of the probe l of the housing. Also, the conical surface of the upper metal fitting 12! 2b1 Cylindrical part 12c and lower metal fitting [3 Cylindrical part 13a
, the bottom portion 13b, and the partition wall portion 13c form an annular pressure equalizing chamber 2l. As shown in the figure, the pressure equalizing chamber 2l has a large diameter at the bottom and gradually becomes smaller in diameter toward the water guide section 20 at the upper end, and the upper end outer circumference is shaped so that the water guide section 20 communicates with the outer circumference. The shape of the nozzle is shorter in axial length than the pressure equalizing chamber of a conventional nozzle, but forms a large-capacity chamber with a large cross section.

In this example, the overall dimensions are 27.5 mm from the lower end of the probe I to the water outlet l6, and 27.5 mm in the pressure equalization chamber 2.
The diameter W of the lower end portion of l is φ68 mm. Therefore, the distance from the probe l to the material to be measured 3 is 37.5 mm.
In this case, the distance from the water outlet 16 of the nozzle to the material to be measured 3 can be set to 10 mm. Further, the longer the length B of the water guiding portion 20, the better; however, in this embodiment, 1. It is set as Omrt.

Next, to explain the operation of the above nozzle, water supplied from the water supply port l5 provided in the upper metal conical part 12b flows downward into the pressure equalizing chamber 2l, as shown by the arrow in FIG. 1(A). flowing towards. And, within the pressure equalization chamber 2l,
In particular, since the central partition wall 13c is inclined so as to expand the volume of the pressure equalization chamber toward the lower end, the pressure equalization chamber 2
The water flowing into I flows into the pressure equalizing chamber 21 so as to accumulate on the bottom side. After the pressure equalization chamber 21 is completely filled with water, the water is guided to the orifice-shaped water guide section 20 at the upper part, and then passed through the nozzle section 17 and is injected from the water outlet l6.

An amount corresponding to this injection amount is supplied from the water supply port 15, so that the pressure equalizing chamber 2l is always completely filled with water.

In the above-mentioned nozzle, the pressure equalizing chamber 2 with a large cross-sectional area
The pressure of the inflowing water in the circumferential direction becomes almost uniform within the pressure equalizing chamber 2I, and on the way from the pressure equalization chamber 2I to the nozzle 17, a small gap water guide portion is formed which is annular and has a relatively long flow path. 20, furthermore, the pressure of the water in the circumferential direction becomes uniform.

Therefore, water flows into the nozzle 17 with uniform pressure in the circumferential direction, and the water column sprayed from the water outlet 6 toward the material 3 to be measured is maintained at a long and stable water column with uniform pressure in the circumferential direction. It can be done. In addition, as mentioned above, since the pressure in the circumferential direction is uniform and the pressure equalizing chamber 2I is always filled with water, air bubbles are difficult to generate and entrainment of air bubbles can be prevented. I can do it.

In this way, since a long and stable water column can be formed, accurate measurement results can be obtained even when the distance from the water outlet 16 of the nozzle to the material to be measured 3 is doubled compared to conventional nozzles. can be obtained.

FIG. 2, FIG. 3, and FIG. 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/m3 and a dynamic viscosity coefficient of 1.0 1
l Ql m''/S and an inflow velocity of 0.7 m/S are used.

FIG. 2 (AXB) shows comparative data when the nozzle of the present invention is used and when the conventional nozzle shown in FIG. 1O is used.

In this experiment, the distance from the water outlet to the measurement material was 15 mm.
+ binding, and the fluctuation in the height of the reflected echo was investigated. Second
Figure (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, and almost no whisker-like noise is generated. On the other hand, Fig. 2 (B) shows the case when a conventional nozzle is used, and the fluctuation is large in the range of 4 to 6 cm.
Whisker-like noise is also occurring sporadically.

FIGS. 3 and 4 are computer-generated vector diagrams of the water flow within the nozzle according to the present invention. Figure 3 shows the water flow vector across each nozzle 17, and Figure 3 (A) shows the upper end of the nozzle (the part facing the probe 1, the water outlet 1).
6), Figure 3 (B) is the middle part of the nozzle part (13.75 mm above the water outlet), Figure 3 (
C) is a cross-sectional view in the vicinity of the water outlet (5.5 mm above the water outlet).

In addition, each cross-sectional view shows a half side part from 0 to 180 degrees, and 1
The water flow vector is shown every 0 degrees, but at the left end of the figure, it is subdivided into every 6 degrees.

The dots or lines indicate the flow velocity, and the flow velocity increases according to the length of the line, and the arrow attached to the line indicates the flow direction.

As shown in FIG. 3(A)-1 and FIG. 3(A)-11, which is a partially enlarged view, the nozzle portion! At the upper end of the nozzle 7, the vector of the water flow is uniform and smooth in the entire circumferential direction, and the direction is also toward the center of the nozzle part. Also,
In FIG. 3(C), the flow velocity distribution in the pressure equalizing chamber 5.5 gates above the water outlet has a circumferential component remaining due to the influence of the inflow from the supply port. However, from (C) 8.25
Flow velocity distribution in the pressure equalization chamber above mm, that is, Fig. 3 (B
), the pressure is fairly equalized and the circumferential component is considerably small. The flow velocity distribution in the upper part of the nozzle is all directed toward the center as shown in FIG. 3(A), and the circumferential direction component that causes rotation is almost eliminated.

FIG. 4 is a simulation of the longitudinal section of the nozzle, and it is verified that the water is in an equal pressure state throughout the pressure equalizing chamber 21.

The present invention is not limited to the structure shown in FIG. 1, but can also be made into structures shown in FIGS. 5 to 8.

In each of the modified examples shown in FIGS. 5 to 8, the nozzle upper fitting l2° and the nozzle lower fitting l3° form a horizontally elongated cylindrical nozzle housing with a diameter larger than the axial length. ing.

First, in the modification shown in FIG. 5, the shape of the partition wall part 30 of the nozzle lower metal fitting 13' is modified as shown in the figure, and the part 31 protruding from the central water outlet [6°] of the bottom part 13b' is It has a cylindrical shape, and is provided with an inclined protrusion 32 that protrudes outward largely at its upper end. The upper surface 32a of the protruding part 32 is parallel to the inclined surface 33 of the opposing upper metal fitting 12', forming a water guiding part 20' having a long distance B, and a pressure equalizing chamber 21' having a large volume below the protruding part 32. is formed. Incidentally, the reason why the upper surface 32a of the protrusion 32 is inclined is to make it easier to remove air bubbles, and the reason why the lower surface 32b of the protrusion 32 is inclined is to make it easier to remove air bubbles and to reduce the acoustic This is because by making the surface close to the curved surface of the lens, smooth streamlines can be obtained and bubbles will not adhere to the acoustic lens surface. In addition, there are two to three water supply ports at intervals on the outer wall of the pressure equalization chamber 21'! 5
' is provided. By providing a plurality of water supply ports at intervals, it is possible to reduce the influence of disturbances at the water supply ports on the entire system.

The modification shown in FIG. 6 is the protrusion 3 of the modification shown in FIG.
2 is made to protrude in a direction perpendicular to the axis without being oblique. This structure has the advantage of being easy to process and inexpensive to manufacture.

In the modification shown in FIG. 7, the water outlet 16' is directed upward,
This can be suitably used when forming a water column upward. That is, the bottom part 13 of the nozzle lower metal fitting 13°
From b', as shown in the figure, the partition wall part 40 is formed so as to be inclined in a mountain shape and protrude upward with the central water outlet IS' as the center. The center shaft hole of the partition wall 40 is connected to the nozzle part 1.
It is closed at 7 degrees, and the nozzle portion 17' is tapered toward the water outlet. On the other hand, the nozzle upper metal fitting! 2 is formed with a parallel inclined protruding portion 4l that faces the inclined surface 40a of the partition wall portion 40, and the inclined portion 4! and tilted 4
A water guide section 20'' is formed between the water guide section 0a, and a pressure equalizing chamber 21' is formed on the upper side separated from the water guide section 20° by the inclined protrusion 41.

FIG. 8 is also a modified example that is suitable for use because air bubbles can easily escape when forming a water column upward. At the same time, a partition wall 50 is provided on the upper side that projects horizontally, and a water guide section forming wall 5 that projects upward from the outer edge of the partition wall 50 is provided.
l is installed. With the above configuration, the length of the water guide portion 20' that communicates with the nozzle hole 17' from the pressure equalization chamber 21 is made very long.

Effects of the Invention As is clear from the above explanation, according to the water column nozzle according to the present invention, the pressure of the water supplied from the water supply port is almost equalized in the circumferential direction in the pressure equalization chamber having a large cross-sectional area. At the same time, the water flows from the pressure equalization chamber to the nozzle through the water guide, and the water guide has an annular shape with a small gap to form an orifice and a long flow path. It is possible to flow in a uniform pressure state in the circumferential direction from the entire circumferential direction. Therefore, in the nozzle part, the pressure in the circumferential direction is made uniform, and it becomes possible to stably spray the water column from the water outlet over a long distance.

In addition, the nozzle of the present invention has a large cross-sectional area and a short axial length, so the length from the water outlet of the nozzle to the material to be measured can be made longer than in the past. In addition to being able to form a stable water column as described above, it also has the advantage of improving the accuracy of reflected echoes.

[Brief explanation of drawings]

FIG. 1(A) is a vertical cross-sectional view showing an embodiment of the nozzle according to the present invention, FIG. 1(B) is a cross-sectional view of the nozzle upper metal fitting, FIG. 1(C) is a cross-sectional view of the nozzle lower metal fitting, and FIG. 2(A) and 2(B) are diagrams comparing experimental data between the nozzle shown in FIG. L of the present invention and a conventional nozzle, and FIG. 3(A)
-r, Figure 3 (A) - II, Figure 3 (B), Figure 3 (C) are computer generated vector diagrams of water flow in each cross section of the nozzle section shown in Figure 1 of the present invention. Drawings drawn by simulation, FIG. 4 is a drawing similar to FIG. 3 in the longitudinal section of the nozzle shown in FIG. 1 of the present invention, FIGS. 5 and 6,
7 and 8 are Ichiro cross-sectional views showing displacement examples of the present invention, FIG. 9 is a drawing showing an ultrasonic pulse/eco one-type measuring device to show an example of the use of the nozzle according to the present invention, and FIG. 1
0 and 11 are cross-sectional views showing conventional nozzles. ...Probe, 2.. Nozzle upper fitting, 2a.. Cylindrical part for probe attachment, 2b.. Conical part, 2c.. Cylindrical part for nozzle lower fitting attachment, 3.. Nozzle lower fitting, 3a. -Cylindrical part, 13b...Bottom part, 3c...Partition wall, 15...Water inlet, 6...Water outlet, l
7. Nozzle section, 20. Water guide section, 21. Pressure equalization chamber.

Claims (1)

[Claims] 1. A nozzle upper metal fitting and a nozzle lower metal fitting are combined to form a housing having a short axial length and a large cross-sectional area, and the probe is placed so that its tip surface is the upper surface of the housing. The probe is attached to the nozzle upper metal fitting so as to be exposed at the axial center, and a water outlet is formed at the bottom axis of the nozzle lower metal fitting facing the tip surface of the probe, and communicates with the water outlet. The nozzle part extending to the vicinity of the tip surface is formed by a cylindrical partition wall part protruding from the nozzle lower metal fitting, and the partition wall part is provided with a protrusion part in the outer circumferential direction, and the protrusion part and the nozzle upper part are provided with a protrusion part in the outer circumferential direction. A large volume annular pressure equalizing chamber is formed between the inner surface of either the upper or lower side of the metal fitting, and an annular water guide part with a small gap is formed between the inner surface of the other side, and the inner peripheral part of the water guide part is formed. communicates with the upper end of the nozzle portion facing the end face of the probe, and communicates the outer circumferential portion with the pressure equalization chamber, furthermore, a water supply port is provided on the outer wall of the pressure equalization chamber, and a water supply port is provided into the housing from the water supply port. A water column nozzle characterized in that the inflowing fluid passes through a water guide part from a pressure equalizing chamber, contacts an end face of a probe, flows into a nozzle part, and is injected from a water outlet. 2. A cylindrical section for mounting a probe is formed at the axial center of the nozzle upper fitting, and an outward protrusion is provided from the outer peripheral surface of the cylindrical section, and the protrusion allows both the upper and lower surfaces of the nozzle lower fitting to be attached. 2. The nozzle according to claim 1, further comprising a pressure equalizing chamber and a water guide section formed between the nozzle and the nozzle.