JPS6232412B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wall soil pressure meter that is attached to a wall surface and used to detect the vertical stress exerted on the wall surface from a fluidized granular material such as fluidized sand grains.

As shown in Fig. 1, the conventional soil pressure gauge has a double diaphragm structure consisting of a large-diameter primary diaphragm 1 as a pressure-receiving surface and a small-diameter secondary diaphragm 3 to which a strain gauge 2 is bonded. Next, a mercury filling chamber 4 is provided by reducing the gap with the diaphragm 3, and mercury is sealed therein.The vertical load applied to the pressure-receiving surface is converted into fluid pressure, and the fluid pressure is used to control minute displacements of the pressure-receiving surface. It is configured such that it is transmitted to the secondary diaphragm 3 at an expansion rate approximately proportional to the square of the diaphragm diameter ratio, and can be detected with high sensitivity by the strain gauge 2 bonded to the diaphragm 3.

As shown in FIG. 2, another example of a conventional soil pressure meter has a primary diaphragm structure including a bottomed cylindrical case 5 and a diaphragm 6 mounted on the open end side of the cylindrical case 5. So, diaphragm 6
The central part is formed thickly to form a pressure receiving surface part 6a, the peripheral part is formed thinly to form a strain generating part 6b, and the peripheral part is further formed thinly to form a crowning part 6c for attaching to the cylindrical case 5. A strain gauge 2 is bonded to the inner surface of the strain portion 6b, and the vertical load applied to the pressure receiving surface portion 6a can be detected by the strain gauge 2 bonded to the strain generating portion 6b.

However, when these conventional soil pressure gauges are installed on a wall, the soil pressure gauge itself is deformed. In the case of the above example, the strain generating portion 6b is deformed, so that there is a problem that the cutting edge unbalance value changes significantly. Furthermore, if the wall surface itself is deformed, the earth pressure meter itself is likely to be deformed as well, and there is a possibility that a vertical stress different from the true value may be detected. Furthermore, since both the primary diaphragm 1 in the former case and the strain-generating portion 6b of the diaphragm 6 in the latter example are thin, they are susceptible to impact and easily wear out.
There is a problem in that the output voltage sensitivity changes.
Furthermore, as in the former example, there is a risk of mercury leakage in the mercury-enclosed type, so there is a drawback that it cannot be used for detecting the fluid pressure of foods and the like.

The present invention was made to solve these problems, and it is easy to install on a wall, and when doing so, there is little change in the initial unbalance value, and the soil pressure meter itself is not deformed by deformation of the wall itself. The impact resistance of the pressure receiving plate is high, so the output voltage sensitivity is not affected by wear, so it can be used with confidence for detecting the pressure of all types of fluid powder and granules, as well as food products, and the output equivalent strain at the rated output. Provided is a wall soil pressure gauge that can reduce the amount of deflection of a pressure receiving plate under a constant condition, that is, can significantly reduce the value of the ratio between pressure receiving plate displacement and pressure receiving plate diameter, and can derive an output that accurately corresponds to the applied pressure. It is intended to.

That is, the gist of the present invention is to provide a pressure-receiving cylinder that has a cylindrical shape with a bottom and has a high rigidity and whose bottom part is a pressure-receiving plate; It is considered a small diaphragm,
a strain tube housed in the pressure tube with a gap between the pressure tube and the inner wall of the pressure tube such that the diaphragm surface faces the inner wall of the pressure plate; and a center of the diaphragm of the strain tube. and a transmission rod that connects the central part of the pressure receiving plate of the pressure receiving cylinder and the cylindrical part of the pressure receiving cylinder and the cylindrical part of the strain cylinder, the rod is elastic in the axial direction and is elastic in the radial direction. It has a bottomed cylindrical shape with a highly rigid circular plate and a mounting flange on the bottom side, and the pressure receiving surface of the pressure receiving plate is exposed to create a gap between the pressure receiving cylinder and the strain generating cylinder and the inner wall. and a cylindrical case with a bottom that is housed through watertight means, transmits the vertical load applied to the pressure receiving plate to the diaphragm of the strain tube via the transmission rod, and reduces the amount of strain generated in the diaphragm. The structure is such that a strain gauge attached to the diaphragm converts the output into an electrical output.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a partially cutaway front view showing the configuration of an embodiment of the present invention.

In the figure, reference numeral 7 denotes a pressure receiving plate forming a pressure receiving cylinder in the shape of a bottomed cylinder with an open end.The pressure receiving surface 7a at the bottom is formed thickly to increase rigidity, and an annular groove is formed on the side circumferential surface of the pressure receiving plate 7. 7b is formed, and the pressure receiving surface portion 7
A female thread 7e is formed at the center of the inner (back) side of a. Reference numeral 8 denotes a strain-generating cylinder having a bottomed cylindrical shape with one end open.The cylindrical portion 8a is formed thickly to increase rigidity, and the diaphragm 8b at the bottom is formed thinly to reduce rigidity. In the center of the surface,
A transmission rod 9 having a male screw 9a is fixed, and a circular plate 10 having a thin-walled brim shape and having low rigidity and elasticity in the axial direction and high rigidity in the radial direction is attached to the side circumference of the cylinder. A contact portion 1 extending in a direction perpendicular to the side circumferential surface and having a wall thickness approximately the same as that of the open end 7c of the pressure receiving plate 7 is provided at the circumferential end of the circular plate 10.
0a is formed, and an internal thread 8d is formed at the open end 8c. Reference numeral 11 denotes a bottomed cylindrical case with one end open and a mounting flange on the closed end (bottom) side, and at least the mounting flange 11a and the bottom 11b are formed thick to increase rigidity.
This mounting flange 11a has a through hole 11c for a tightening bolt for attaching this earth pressure gauge to a part to be measured.
The bottom part 11b is provided with an insertion hole 11d for a tightening bolt 17 for connecting the case 11 and the strain tube 8. It is formed at a height such that when the pressure receiving plate 7 is assembled, it becomes approximately the same surface as the pressure receiving surface portion 7a of the pressure receiving plate 7. Note that reference numeral 11f is a circumferential groove having a concave cross section formed on the inward upper surface of the flange portion 11a. A strain gauge 12 is bonded to the inner surface (back surface) of the diaphragm 8b. Reference numeral 13 denotes a cable lead-out part, which is fixed to the bottom 11b of the case 11 by, for example, screwing, welding, etc. Inside the cable lead-out part, a gauge lead 14 connected to a terminal of the strain gauge 12 is connected to a gauge lead 14 which is drawn out to the outside and connected to a measuring instrument. The continuous cables 15 are connected. 1
A sealing O-ring 6 is fitted into the annular groove 7b of the pressure receiving plate 7 with a portion thereof protruding. Numeral 17 is a tightening bolt for attaching the strain tube 8 to the case 11.

The pressure receiving plate 7 and the strain cylinder 8 are connected by screwing the male thread 9a of the transmission rod 9 fixed to the strain cylinder 8 into the female thread 7e formed on the pressure plate 7. At this time, the open end 7c of the pressure receiving plate 7 and the contact portion 10a of the annular plate 10 come into contact. This contact portion is fixed by welding. Strain tube 8 assembled in this way
is attached to the case 11 by inserting the tightening bolt 17 into a hole 11d formed in the bottom 11b of the case 11 and screwing it into a female thread 8d formed in the bottom of the strain cylinder 8. At this time, the inner peripheral surface of the cylindrical portion 11e of the case 11 and the outer peripheral surface of the pressure receiving plate 7 are
Watertight sealing is provided by the ring 16, and the pressure receiving surface portion 7a of the pressure receiving plate 7 and the opening end surface of the cylindrical portion 11e of the case 11 are aligned on substantially the same plane. Apply the mounting jig 19 of an appropriate thickness to the mounting wall 18 (for example, the wall of a pipe for pumping earth and sand), adjust the pressure receiving surface 7a of the pressure receiving plate 7 so that it is flush with the mounting wall 18, and attach it to the mounting wall 18. The jig 19 is fixed by welding. After that, attach the case 11 to the wall 18
and fit into the hole drilled in the mounting jig 19.
Then, the case 11 is attached to the mounting wall 18 via the mounting jig 19 by inserting the tightening bolt 20 into the hole 11c drilled in the flange 11a and further screwing into the female thread 19a formed in the mounting jig 19. . Note that an O-ring 21 inserted between the mounting flange 11a and the mounting jig 19 is provided to prevent fluid from leaking to the outside. In this way, granular materials such as earth and sand, grains, ores are accumulated on the mounting wall of the measurement target to which the wall soil pressure gauge is attached, and their weight is statically applied, or fluid granular materials are moved. When this dynamic load is applied, the pressure receiving plate 7 receives a vertical load (or pressure) on its pressure receiving surface portion 7a and is displaced in the axial direction of the cylinder. At this time, since the pressure receiving plate 7 is formed to have a high rigidity, the amount of deflection thereof is so small that it can be ignored, and there is only movement in the axial direction.

This displacement force of the pressure plate 7 in the axial direction is applied to the transmission rod 9
The pressure is transmitted to the diaphragm 8b through the diaphragm 8b, causing the diaphragm 8b to be bent significantly, and is also transmitted from the open end 7c of the pressure receiving plate 7 to the annular plate 10 extending from the strain tube 8, causing the annular plate 10 to deform. The amount of deflection of the diaphragm 8b is converted into an electrical quantity by changing the resistance value of a strain gauge 12 bonded thereto, which is extracted, and then converted into a pressure to be displayed or recorded.

As described above, according to the above embodiment, first of all, since the mounting flange for attaching to the wall surface of the object to be measured is provided at the bottom of the case, the attachment is easy.
Furthermore, since the flange portion and the cylindrical portion of the strain tube are formed to have high rigidity, changes in the initial unbalance value when the earth pressure gauge is attached to a wall surface can be extremely minimized.

Second, similar to the above reason, deformation of the wall soil pressure gauge itself is unlikely to occur due to deformation of the wall itself, and therefore even if the wall itself deforms, it is hardly transmitted to the diaphragm and is not perpendicular to the wall. The true value of stress can be detected and measured.

Thirdly, since the pressure receiving plate itself has a high rigidity, it is strong against impact, wear due to sliding movement of earth and sand can be almost ignored, and output voltage sensitivity is not affected.

Fourthly, if the pressure receiving plate has high rigidity and the wall surface to be measured and the pressure receiving surface are aligned almost on the same plane, there will be no protruding parts that impede the movement of particulate matter. Force is difficult to transmit, and even if a lateral force were to be transmitted to the pressure receiving plate, the strain gauge is arranged so that it cannot be sensed in the lateral direction, and the inner wall of the cylindrical portion of the pressure receiving cylinder, which is rigid, is also highly rigid and causes strain. Since it is connected to the outer periphery of the cylindrical part of the cylinder by a circular plate which has low rigidity and elasticity in the axial direction and relatively high rigidity in the radial direction, tilting of the pressure receiving plate is reliably prevented. The diaphragm to which the strain gauge is bonded hardly receives any bending moment, and can only detect the vertical component load (pressure) applied to the pressure receiving surface. In addition, almost no lateral force is applied to the upper surface of the cylindrical portion of the case, but even if it were applied, the structure is such that it is difficult to transmit to the pressure receiving plate and the diaphragm of the strain tube. Therefore, it is not affected by forces from the lateral direction.

Fifth, since there are no dangerous substances such as mercury inside the wall soil pressure meter, it can be safely used to measure the pressure of fluidized powder particles such as foods.

Sixthly, the load received by the pressure receiving plate is directly transmitted from the center of the pressure receiving plate to the center of the diaphragm of the strain cylinder via the transmission rod, so that the load received by the pressure receiving plate is not applied to the pressure receiving plate. The load is greatly expanded and transmitted to the diaphragm, deforming the diaphragm greatly. On the other hand, by appropriately setting the thickness of the circular plate extending around the strain tube, the displacement of the diaphragm can be reduced. Since the amount can be adjusted, the amount of deflection of the pressure receiving plate at the rated output and the output equivalent strain amount can be adjusted, and a larger output equivalent strain amount can be detected with a smaller amount of deflection. Therefore, it is possible to obtain a detection output that accurately corresponds to the applied load even though the configuration is extremely simple.

Seventh, since an O-ring as a watertight means is interposed between the inner circumferential surface of the case and the outer circumferential surface of the pressure-receiving plate, water, powder, etc. are prevented from entering the case, and the displacement of the pressure-receiving plate is prevented. There is no problem with the operation, and since moisture does not enter the case, performance deterioration due to moisture absorption of the strain gauge can be prevented. Since the strain gauge is enclosed within the strain cylinder, even if moisture leaks from the O-ring and enters the case, it will not reach the strain gauge.

Note that the present invention is not limited to the embodiments described above, and various modifications can be made without changing the gist thereof.

For example, in the above embodiment, the mounting flange was constructed integrally with the case, but it may also be formed as a separate member and then integrated by means such as screwing or welding, or the strain tube and the case may be integrated. It may be integrally molded.

In addition, this earth pressure meter can be applied to wall earth pressure in dems and building foundations, the tip of drilling blades used in ore mining, tunnel excavation, etc., walls of silos and hoppers, and pumping of pulverized coal. It can be attached to the wall of a pipe to measure the wall pressure.

As detailed above, according to the present invention, it is easy to install it on a wall surface, there is little change in the initial unbalance value, it is less affected by the deformation of the wall surface itself, and the pressure receiving plate has excellent impact resistance. In addition, the output voltage sensitivity is not affected by wear, so it can be safely used for detecting the pressure of all liquid powder fluids as well as food products, and the amount of deflection of the pressure receiving plate can be reduced under conditions where the output equivalent strain at the rated output is constant. In addition, even if an uneven load (or unevenly distributed load) or a frictional force acts on the pressure receiving plate in the direction along the pressure receiving surface of the pressure receiving plate, it is not substantially transmitted to the diaphragm. Vertical component force (pressure) applied to the plate
It is possible to provide a wall soil pressure gauge that can obtain an electrical output that accurately corresponds to the

[Brief explanation of the drawing]

1 and 2 are sectional views showing the configuration of a conventional soil pressure meter, FIG. 3 is a partially cutaway front view showing the configuration of an embodiment of the wall soil pressure meter according to the present invention, and FIG. 4 is the same. It is a partially cutaway front view showing a state in which the embodiment is attached to a wall surface. 7... Pressure receiving plate, 7a... Pressure receiving surface portion, 8... Strain cylinder, 8b... Diaphragm, 9... Transmission rod, 10
... circular plate, 11 ... case, 11a ... mounting flange, 12 ... strain gauge, 13 ... cable lead-out section, 16, 21 ... O-ring, 18 ... mounting wall.

Claims (1)

[Claims] 1. A pressure receiving cylinder having a bottomed cylindrical shape and having a pressure receiving plate at the bottom, and a pressure receiving cylinder having a bottomed cylindrical shape with a thick walled cylinder having high rigidity and a diaphragm having low rigidity at the bottom. a strain-generating cylinder housed in the pressure-receiving cylinder such that there is a gap between the strain-generating cylinder and the inner wall thereof and the diaphragm surface faces the inner wall of the pressure-receiving plate; a transmission rod that connects the center of the pressure receiving plate of the cylinder; and a circle that is elastic in the axial direction and rigid in the radial direction and that connects the cylindrical part of the pressure receiving cylinder and the cylindrical part of the strain cylinder. It has a bottomed cylindrical shape with a ring plate and a mounting flange on the bottom side, the pressure receiving surface of the pressure receiving plate is exposed, and there is a gap between the pressure receiving cylinder and the strain generating cylinder and the inner wall, and watertight means. The vertical load applied to the pressure receiving plate is transmitted to the diaphragm of the strain tube via the transmission rod, and the amount of strain generated in the diaphragm is attached to the diaphragm. A wall soil pressure gauge characterized in that it is configured to convert the output into an electrical output and take it out using a strain gauge made of the same material.