JPS6250511A - Sand level meter - Google Patents

Abstract

PURPOSE:To exactly measure the level of sand by a method in which micro waves are transmitted from a transmitting antenna toward the face of sand in a cylinder, and reflected waves are received by a receiving antenna and processed on the basis of the time lag between the transmission and the receiving. CONSTITUTION:When micro waves M are transmitted from a transmitting antenna 16 toward a sand face 12a in the lower part of a cylinder 10, the waves M collide with the sand face 12a and the upward reflecting waves are received by a receiving antenna 18. On the basis of the time lag between the transmission and receiving of the waves M, the sand face 12a is measured for level by a processor 20 and the results are sent out to a displayer and a recorder. When the measurement is ended and sand 12 is charged, a protective case 14 is turned the axial direction of the cylinder 10 by an air cylinder 22 to protect the antennas 16 and 18 and the processor 20.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a sand level gauge used when constructing compacted sand piles, and particularly to a sand level gauge using microwaves.

(Conventional technology and problems) Conventionally, in order to improve the soil quality of soft ground, the so-called sand compaction method has been used, in which sand is buried in the ground and compacted by applying vibrations and shocks to form sand piles. provided.

In the sand compaction method, a hollow cylindrical sheath is usually buried in the ground, and a specified amount of sand is poured into the sheath.
A sand pile of a predetermined length was created by lifting the sheath slightly and applying vibration and impact to the sand ejected at the tip of the sheath, and repeating this operation one after another.

The strength of the formed sand pile is determined by the compaction of the sand,
This was confirmed by measuring the position of the sand surface after compaction to ensure the specified strength7).

As a sand level gauge, for example, a metal electrode plate is suspended inside the sheath, a constant voltage is applied between the plate and the sheath, and the change in resistance between the electrode plate and the sheath is used to measure the sand level. Means are provided for sensing the surface.

However, with this method, the electrode plate is fixed to a weight or the like, connected to an electric cord, and suspended vertically within the sheath, but this connection is often severed when sand is thrown in. Sometimes the electrode plate touched too much and came into contact with the sheath, resulting in malfunction.

Another disadvantage was that when sand was added, it adhered to the electrode plates, reducing measurement sensitivity.

On the other hand, in order to solve these problems, devices have been proposed that measure the sand surface using ultrasonic waves without making direct contact with the sand, but this method also has the following problems. .

In other words, normally in this type of construction method, pressurized air is injected from above the sand surface in order to facilitate the evacuation of the sand inside the sheath, but the sound of the compressed air being ejected during injection sometimes made measurements impossible. .

Injection sound contains a wide range of frequency components, making it difficult to measure even if the ultrasonic frequency was changed.

In addition, the mechanical impact noise during compaction is relatively loud, and when construction work is being carried out in parallel at nearby locations, this impact noise also affects the construction, making accurate measurement difficult.

This invention was made in view of these problems, and its purpose is to provide a sand level meter that can measure sand level without being affected by the sound of air jets or surrounding mechanical impact sounds. It is about providing.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a sand compaction method for compacting sand put into a hollow cylindrical body. A transmitting antenna that projects microwaves toward the lower part of the body; a receiving antenna that receives reflected waves of the microwaves from the sand surface; It is characterized by comprising a processing device that calculates the sand surface based on the received reflected waves, and a protective case that houses the transmitting/receiving antenna and the processing device.

(Function) The sand level meter with the above configuration measures the sand surface by projecting and reflecting microwaves without directly contacting the sand surface, so it does not make any noise when discharging the sand or other sand piles. Accurate measurements can be made without being affected by surrounding sound waves that occur during construction, such as the sound of the impact created during construction.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show an embodiment of a sand level meter according to the present invention.

The sand level meter shown in the same figure puts sand 12 into a hollow cylindrical body 10 that is submerged in the soil, discharges the sand 12 from its tip, and compacts it by impact and vibration. It is used in the sand compaction construction method in which sand piles are created inside, and is installed near the upper end of the cylindrical body 10.

As shown in detail in FIG. 2, the sand level gauge includes a disc-shaped protective case 14 and a transmitting antenna 1 housed inside the protective case 14.
6, a receiving antenna 18, and a processing bag W120.

The protective case 14 protects the internal antennas 16, 18, etc. from the sand 12 thrown in, and is made of a material that does not absorb electromagnetic waves, such as rubber or plastic.

The above method/receiving antenna 16.18 is a microwave M (
900 MHz to IGHz), and as shown in FIG. It is located on the top side.

The processing device 20 is located on the bottom side of the protective case 14 and is electrically connected to the antenna 16. It is comprised of an amplifier for amplification, an arithmetic unit for calculating the sand surface based on the time difference between transmission and reception of the microwave M projected toward the sand surface 12a, a power source battery, and the like.

The protective case 14 that houses the antenna 16, 18 and the processing device 20 is connected to the cylinder 10 through its radially provided axis.
An air cylinder 22 is provided on the outside of the cylindrical body 10 to rotate the protective case 14 in any direction via this shaft.

During measurement, the sand level meter with the above configuration is rotated by the air cylinder 22 so that the protective case 14 is perpendicular to the axial direction of the cylindrical body 10, as shown by the solid line in FIG. A certain transmitting/receiving antenna 16.18 is on the sand surface 12
It is set so that it faces side a.

In this state, the microwave M is projected from the transmitting antenna 16 toward the sand surface 12a below the cylinder 10, and the microwave M
The receiving antenna 18 receives the reflected wave upward after colliding with the sand surface 12a.

Then, the sand surface 12a is measured by the processing device 20 based on the time difference between transmission and reception of the microwave M, and the results are outputted to an appropriate display device and recording device.

Microwave M can be generated by the sound of compressed air jetting out like an ultrasonic wave,
The sand surface 12a can be accurately measured because it is not affected by the impact noise caused by forming other sand piles.

On the other hand, when the sand 12 is put in after the measurement, the first
As shown by the dotted line in the figure, the protective case 14 is rotated by the air cylinder 22 in the axial direction of the cylindrical body 10.

As a result, the sand 12 is smoothly introduced into the cylindrical body 10, and since the antennas 16, 18 and the processing device 20 are inside the protective case 14, damage caused by the introduction of the sand 12 is prevented.

FIG. 3 shows another embodiment of the sand level meter according to the present invention, and only its features will be described below.

In this embodiment, the transmitting/receiving antennas 16, 18 and the processing device 20, which are the basic structure of the sand level gauge, are housed in a disc-shaped protective case 14, as in the above embodiment.

In this embodiment, an opening 26 is formed below an on-off valve 24 provided near the upper end of the cylindrical body 10 to control the introduction of sand 12, and this opening 26 is closed to form a hollow disk-like shape. A rotary air cylinder 30 is provided at the joint between the storage case 28 and the cylindrical body 10 on the outside, and the rotating shaft of the cylinder 30 is connected to a stay 148 provided on the protective case 14 to provide protection. Case 1
The protective case 14 is supported in a substantially horizontal state with the upper and lower surfaces of the case 4 perpendicular to the axis of the cylinder 10, and the protective case 14 is configured to be able to move forward and backward into the cylinder 10 through the opening 26 by rotation of the air cylinder 30. .

The transmitting/receiving antennas 16 and 18 inside the protective case 14 are located on the bottom side of the case 14, and are rotated to the solid line position in FIG. 3 at the time of measurement.
Measure 2a.

When the sand 12 is introduced, it is rotated to the imaginary line position shown in FIG. 3 and evacuated into the storage case 28.

(Effects of the Invention) As explained above in detail in the actual fMW4, the sand level meter according to the present invention is a micro-sand meter that is completely unaffected by the sound waves generated inside and outside the cylindrical body into which sand is charged and compacted. Since waves are used, the sand surface can be accurately measured even if other sand piles are being constructed in close proximity.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the installation state of the sand level meter of the present invention, Figure 2
The figure is a view of the main parts of the sand level gauge. FIG. 3 is an explanatory diagram of an installed state showing another embodiment of the present invention. 10...Tube rest 12...
... Sand 14 ... Protective case 16 ...
・Transmission antenna 18...Reception antenna 20・
... Processing device 22 ... Air cylinder
24...Opening/closing valve 26...Opening
28...Storage case 30...Rotary air cylinder Patent applicant Obayashi Corporation Representative Patent attorney - Irokanosuke Figure 1 (A)

Claims (3)

[Claims] (1) In the sand compaction method of compacting sand put into a hollow cylindrical body, a transmitting antenna that is located near the upper end of the hollow cylindrical body and projects microwaves downwardly of the hollow cylindrical body; a receiving antenna that receives reflected waves from the sand surface; a processing device that transmits the microwave to the transmitting antenna and calculates the sand surface based on this and the reflected wave received by the receiving antenna; A sand level meter comprising a protective case that houses the transmitting/receiving antenna and the processing device. (2) The protective case is rotatably attached within the hollow cylinder, and is positioned in the axial direction of the hollow cylinder when sand is being introduced, and is positioned perpendicular to the axis during measurement. A sand level gauge according to claim 1, characterized in that: (3) The protective case is attached to the side of the hollow cylinder so that it can move forward and backward into the hollow cylinder, and is moved back out of the hollow cylinder when the earth and sand is thrown in, and enters into the hollow cylinder during measurement. 2. The sand level meter according to claim 1, wherein the sand level meter is positioned in a direction perpendicular to its axis.