JPS6316711B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field to which the invention pertains] The present invention relates to a groundwater particle motion measuring device, and in particular, to a groundwater flow measurement device that enables repeated and continuous measurement of minute flows of groundwater. Regarding equipment.

[Prior art and its problems]

In recent years, in the foundation construction sector in fields such as civil engineering and construction, groundwater flow (flow velocity and/or flow direction) is used to determine whether or not to adopt freezing construction methods for soft ground, or to investigate the progress of groundwater contamination. ) is increasingly needed to be measured as accurately as possible.

On the other hand, a so-called tracer method has been widely used as a method for measuring groundwater flow.
This method involves injecting salt or dye into a specific borehole out of multiple boreholes, examining changes in electrical resistance or concentration over time between it and other boreholes, and determining the time at which the maximum change occurs and The purpose is to perform four simple arithmetic operations based on the position and thereby measure the groundwater flow situation.

However, in this conventional technology, it is necessary to drill a large number of boreholes with a depth of 20 m to 40 m, which results in extremely high survey costs overall, and furthermore, the groundwater flow rate is extremely slow. In some cases, measurements take a long time, and changes in flow due to rain occur during long measurements, making accurate measurements extremely difficult overall.

On the other hand, in recent years, with the intention of improving the above-mentioned drawbacks, propeller-type flow measuring devices, the invention disclosed in Japanese Patent Publication No. 45-25029, or radioisotopes are introduced into flowing water, and the Various methods have been proposed, including methods for measuring flow by tracing changes in the radiation dose distribution due to flowing water.

However, when measuring flow using a propeller type, it is difficult to measure minute flow velocities of, for example, 2 cm/sec or less. Or, special public service No. 45-25029
The method described in the publication attempts to estimate the groundwater flow situation from the pressure difference due to the upward and downward flow of water in the borehole that acts on the disk by lowering the disk into the borehole. However, even with this method, as with the above propeller method, it is actually difficult to accurately measure minute flows in which there is almost no pressure difference between upward flow and downward flow. Furthermore, the methods using radioactive materials always have drawbacks, such as not only being dangerous to handle, but also making the entire device extremely expensive.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a groundwater flow measuring device capable of improving the conventional inconveniences and, in particular, being able to repeatedly measure at least the flow direction of groundwater over a long period of time while maintaining the same settings. .

[Means for solving problems]

Therefore, the present invention includes an observation section in which a plurality of measurement electrodes are arranged concentrically and at predetermined intervals on the same surface at one end, and the fluid to be measured in this observation section has electrical or scientific properties. A probe body is provided in which a displacement fluid pouring mechanism for pouring out different displacement fluids is provided in close proximity to the observation section, and the outer periphery of the observation section of the probe body is sealed with a cylinder that is filled with the displacement fluid as necessary. The measuring device is equipped with a shaped sleeve mechanism that can be moved up and down, communicates the insides of the displacement fluid dispensing mechanism and the observation section, and also replaces part of the liquid in each section when re-measuring. , thereby attempting to achieve the above objective.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 to 10.

FIG. 1 is a schematic explanatory diagram showing an example of actual measurement using the fluid flow measuring device according to the present invention. In this Figure 1, 1 is a groundwater layer (sand layer,
This is a borehole for measurement that is drilled into the depths of the gravel layer, etc. In this borehole 1, a support conduit 2
A measurement probe (hereinafter simply referred to as "probe") 3 suspended via the test probe is inserted down to the test depth. Here, the direction of the probe 3 is confirmed by a compass 4 (see FIG. 2) built into the upper part of the probe 3, and the probe 3 is installed and fixed in a predetermined direction. In the groundwater layer in the ground E, there is a flow of groundwater as shown by the arrow F in the figure, so that the borehole 1 below the groundwater level
Groundwater W gushes out inside the tank, and the probe 3 is immersed in this groundwater W. The probe 3 includes a multicore cable 5 disposed within the support conduit 2.
(see Figure 2), it is electrically connected to external measuring equipment, etc. (not shown).
Groundwater flow is being measured and recorded.

FIG. 2 shows a specific mechanism of the probe 3 mentioned above. In this figure, 6 indicates a cylindrical probe body. One end of the probe body 6, which is the lower end in the figure, is surrounded by a disc-shaped head board 7 made of an insulating material, and a bottom board 8 mounted opposite the head board 7 at a predetermined distance. An observation section 20 is provided. In addition, in this observation unit 20, a substituting fluid having electrical or chemical properties different from that of groundwater, which is the object to be measured (for example, an electrolytic solution such as NaCl solution when groundwater has low conductivity), or A displacement fluid dispensing mechanism 30 for dispensing pure water, etc., is used when the liquid contains NaCl etc. and has a relatively high conductivity.
It is built in. The above-mentioned azimuth gauge 4 is housed in the probe body 6 above the displacement fluid dispensing mechanism 30, and its azimuth signal is sent to the support conduit 2 connected to the center of the upper end of the probe body 6. It is designed to be transmitted to the outside via wiring (not shown) arranged in the . Further, 50 indicates a sleeve mechanism, and 60 indicates a sleeve drive section.

Next, each component of the probe 3 will be explained in more detail.

The head panel 7, which forms the main part of the observation section 20, includes a second
As shown in FIG. 7 and FIG. 7, a plurality of electrode wire groups 9 (described specifically later) projecting downward in FIG. 2 are arranged concentrically and at equal intervals around the electrode wire 10. has been done. The head board 7 includes four threaded columns 21, 21, . . . each having a predetermined length.
... is screwed to the lower end surface of the probe body 6 via a waterproof rubber ring 21A, thereby sealingly fitting the probe body 6. Further, on the top surface of the head board 7 in FIG.
A terminal plate 19 is attached for connecting the terminal to an external circuit, and the end of the multi-core cable 5 described above is fixed to this terminal plate 19, and each electrode of the electrode wire group 9 is connected to the terminal plate 19 via the multi-core cable 5. The lines are individually connected to external signal detection and display means (not shown).

A bottom plate 8, which is provided opposite to the head plate 7, is fixed at the lower end portions of threaded columns 21, 21, . . . with nuts. A space 2 serving as an observation section is formed between the bottom plate 8 and the head plate 7.
When the sleeve mechanism 50 is opened, which will be described later, groundwater can flow into the tube.

On the other hand, the bottom plate 8 functions as the bottom of the container when filling an electrolytic solution (for example, NaCl solution) as a replacement fluid as described later, and also functions as a bottom of the container.
When lowering the whole into the borehole 1, if the whole is pushed down to the bottom of the borehole 1 by mistake, it has a function to prevent damage to the electrode wire group 9 part, and also has a function to prevent the electrode wire group 9 from being damaged. It also has the function of stabilizing the flow of fluid.

Further, a wire mesh 25 is arranged in a cylindrical shape between the peripheral end of the head board 7 and the peripheral end of the bottom board 8 so as to surround the electrode wire group 9. This wire mesh 25
In addition to preventing the intrusion of foreign matter into the space 20 serving as the observation section due to collapse of the hole wall 1A of the borehole 1 shown in FIG. In addition to having the function of removing the influence of external noise, it also suppresses the generation of turbulence that occurs when the sleeve mechanism 50 (described later) rises, and furthermore, it can rectify the water flow in the space 20 serving as the observation section together with the bottom plate 8. ing.

The displacement fluid pouring mechanism 30 that pours out the displacement fluid into the observation section 20 includes spacers 31A, 31A, . . .
A cylinder 31 is fixed to the upper end surface of the head board 7 in FIG. 2 through...
a piston 32 and a piston rod 33 that reciprocate within the cylinder 1; a rod guide member 34 that guides the piston rod 33 at the upper end of the cylinder 31;
and a piston drive section 35 that transmits reciprocating force to the piston. In addition, water conduit pipes 36 and 3 leading to the observation unit 20 from the center of the lower end of the cylinder 31 and the side surface of the upper end of the cylinder 31 in FIG.
6 and 37, 37 are arranged. moreover,
An introduction pipe 38 for feeding replacement fluid from the outside is provided on the side surface of the lower end of the cylinder 31 . This introduction pipe 38 is equipped with a check valve 39,
This prevents the liquid in the cylinder 31 from rising and flowing back to the outside through the introduction pipe 38 even if the piston 32 moves downward.

Further, the piston drive unit 35 of the replacement fluid pouring mechanism 30 includes a small motor 35A whose start, stop, and forward/reverse operation are freely controlled by a first motor control unit (not shown) provided externally. , a reduction gear 35B connected to this motor 35A, and a gear mechanism 39 consisting of a rack 33A and a pinion 33B for transmitting the output of this reduction gear 35B to the piston rod 33 (see Fig. 2). (See Figure 3). Of these, Rack 33A
is formed by processing on the side surface of the piston rod 33. Further, this piston rod 33 is equipped with a rotation prevention mechanism 70 for preventing rotation during this vertical movement.

In the displacement fluid dispensing mechanism 30 configured in this manner, when the piston 32 is lowered by a predetermined stroke by the piston drive unit 35, the cylinder 3
The replacement fluid in the observation unit 1 is poured out into the observation unit 20 via water conduit pipes 36, 36. Incidentally, in this embodiment, the displacement fluid pouring mechanism 30 also serves as a main part of the displacement fluid stirring mechanism 70, as described later.

Next, the sleeve mechanism 50 is composed of a cylindrical sleeve 51 whose lower end is open in FIG. 2, and a sleeve support 52 which is hermetically fixed to the upper end of this sleeve 51. sleeve 5
1 is inscribed in the seal mechanisms 6A, 6B provided on the outer periphery of the probe body 6 and the seal mechanism 8A provided on the outer periphery of the bottom plate 8 forming the observation section 21. It is mounted on the outer peripheral side of the main body 6 so as to be able to move up and down. Further, the sleeve support body 52 is connected to the second part of the probe body 6.
It is locked by a doughnut-shaped connecting plate 6C that is hermetically fixed to the upper end in the figure and the support conduit 2 planted on the connecting plate 6C, and is thereby attached to the upper end of the probe body 6. ing.

Connecting plate 6C of probe body 6 and support conduit 2
The sleeve drive unit 60 described above is provided between the sleeve mechanism 50 and the sleeve mechanism 50 . The sleeve drive unit 60 includes a sleeve lifting mechanism 61 for pulling up the sleeve mechanism 50 to allow external groundwater to flow through the inside of the observation unit 20, and a sleeve lifting mechanism 61 for sealing and shielding the observation unit 20 from the outside. The sleeve pull-down mechanism 62 is configured.

Of these, the sleeve lifting mechanism 61 is configured using water pressure as the driving force, and the sleeve lifting mechanism 61 is configured using water pressure as the driving force.
A through hole 52C formed in the sleeve support 52 and a hydraulic hose 65 connected to the upper end of the through hole 52C are inserted into a gap 63 provided between the connecting plate 6C and the sleeve support 52. Pressurized water is pumped in from the ground through the sleeve mechanism 50, whereby the sleeve mechanism 50 is relatively pulled upward from the state shown in FIG. 4 as shown in FIG. 5. In this case, the water that is forced into the cavity 63 is absorbed by the sealing mechanism 6A described above and the sealing mechanism 5 which is separately provided between the sleeve supporter 52 and the support conduit 2 and which is locked to the sleeve supporter 52.
2A prevents its leakage.

Further, the sleeve pulling down mechanism 62 mainly includes a compression spring 64 installed between the sleeve support body 52 and the support conduit 2 as shown in FIG. That is, the lower end of the compression spring 64 in FIG. There is. Therefore, when the sleeve mechanism 50 is pulled up as shown in FIG. 5 by the sleeve lifting mechanism 61 described above, the compression spring 64 becomes compressed by the upward movement of the sleeve support 52. When the pressure of the water press-fitted into the sleeve lifting mechanism 61 is released by an external operation, the sleeve mechanism 50 is moved to the second position by the pressing force of the spring 64.
The state shown in FIG. 4 is restored. In this case, the water sent into the sleeve lifting mechanism 61 is sent back to the ground via the hydraulic hose 65. In addition, support conduit 2
A sealing mechanism 52B is attached to the sleeve support 52 and seals between the sleeve support 52 and the support conduit 2 at the upper end portion of FIG. This prevents groundwater etc. from entering the interior. Similarly, the pressurized water pressurized into the sleeve pulling mechanism 61 is transferred to the sleeve pulling mechanism 61 by the sealing mechanism 52A described above.
2 is prevented from entering. Also,
Air within the sleeve pulling down mechanism 62 can freely enter and exit the support conduit 2 through ventilation holes 2E and 2F formed in the support conduit 2.

The upward movement of the sleeve mechanism 50 is limited by a stopper 2S formed in the support conduit 2 (see FIGS. 4-5). In this case,
The entire observation section 20 is exposed. Further, the downward movement of the sleeve mechanism 50 is caused by the annular protrusion 2A provided on the support conduit 2 hitting the seal locking member 67 fixed to the sleeve support 52 for locking the seal mechanism 52B described above. It is designed to be limited by abutting (see Fig. 2). In this case, the lower end of the sleeve 51 in FIG.
0 is set in a position that is sealed from the outside.

Here, the overall function and operation sequence of the probe 3 configured as described above will be explained.

First, after filling the observation section 20 and the cylinder 31 with a replacement fluid, the probe 3 is placed in a predetermined borehole 1 as shown in FIG. Next, the sleeve lifting mechanism 61 is operated to slowly pull up the sleeve 51 and set it to the state shown in FIG. As a result, as described above, a state is established in which groundwater can flow into the observation unit 20, and at the same time, measurement of the flow direction and velocity of the groundwater is started as described later. On the other hand, when the sleeve 51 is pulled up, turbulent flow may occur around the observation section 20 as shown by arrow B in FIG. 6, and the replacement fluid may be dispersed irregularly. The action of the wire mesh 25 suppresses the turbulent flow and prevents the displacing fluid from dispersing, thereby making it possible to more accurately measure the flow direction and velocity of groundwater.

Next, when the displacement fluid in the observation section 20 is washed away together with the groundwater and the first measurement is completed, the pressure is released from the pressurized water press-fitted into the sleeve lifting mechanism 61 by an external operation, as described above. As shown in FIG.
The state shown in FIG. 4 is set. in this case,
The observation section 20 is filled with groundwater.

Next, the piston drive unit 3 of the displacement fluid ejection mechanism 30
5 is actuated by external control as described above to lower the piston 32, the displacement fluid in the cylinder 31 flows through the water conduit pipes 36, 36 to the observation unit 20.
At the same time, the groundwater in the observation section 20 is sequentially drawn into the upper side of the cylinder 31 in FIG. 2 through the water conduit pipes 37, 37. In this case, since the displacement fluid that is poured out is poured into the groundwater within the observation section 20, it takes a relatively long time for the displacement fluid to become uniform. This time is not directly involved in the measurement. For this reason, a stirring mechanism 71 is provided within the probe body 6 with the intention of speeding up the work. In this embodiment, the stirring mechanism 71 is configured with the replacement fluid pouring mechanism 30 as its main part.

That is, the stirring mechanism 71 includes the replacement fluid pouring mechanism 30 and a second motor control section (not shown) provided on the ground outside that drives the motor 35A of the piston drive section 35 of the displacement fluid pouring mechanism 30 in forward and reverse directions. It is composed of. Therefore, when the motor 35A of the replacement fluid pouring mechanism 30 is rotated forward and backward by the second motor control section, each fluid in the observation section 20 and the cylinder 31 is The reciprocating movement is repeated via 37. During this reciprocating process, the displacement body uniformly dissolves into the groundwater within the observation section 20, thereby uniformly filling the observation section 20 with the displacement fluid that directly contributes to measurement. In this case, the piston 32 is in the cylinder 3
It is designed to be stopped at the lower end within 1.
Thereafter, exactly the same operations as in the first measurement described above are performed, and thereby a second groundwater flow measurement is performed.

Thereafter, the same process is repeated every time replacement fluid is supplied from the outside into the cylinder 31, thereby moving the aforementioned probe 3 portion to the borehole 1.
It is now possible to measure groundwater flow any number of times by operating it on the ground while it is still installed in the ground.

Next, the configuration of the electrode wire group 9 protruding from the head panel 7 and the specific method of measuring the flow of groundwater described above will be explained.

First, as shown in FIG. 7, the electrode wire group 9 includes outer electrodes 11A, 12A,
..., 18A are arranged concentrically at equal intervals, and corresponding to the outer electrodes 11A to 18A, inner electrodes 11B, 12B, . . . , 18B are similarly arranged concentrically at equal intervals. Therefore, in the embodiment shown in FIG. 7, the electrode wires are arranged radially in eight directions with the electrode wire 10 as the center. Each electrode wire 10, 11A, 11B from now on,
12A, 12B, ... 18A, 18B are approximately 1/2 of the protruding parts from the head board 7 on the head board 7 side.
Parts are insulated. The electrode wires arranged in one direction, for example, the outer electrode 11A, the inner electrode 11B, and the center electrode 10 constitute a set of measurement electrodes. For example, when using the difference in resistivity between the displacement fluid and groundwater,
As shown in FIG. 8, for a pair of fixed resistors R ₁ and R ₂ , the resistance (liquid resistance) RX ₁₁ between the outer electrode 11A and the inner electrode 11B and the resistance between the inner electrode 11B and the center electrode 10 Connect RY ₁₁ with bridge,
A predetermined AC voltage is applied between the outer electrode 11A and the center electrode 10, and a change in the voltage _V11 between the terminal S between the fixed resistors _R1 and _R2 and the inner electrode 11B is measured. . By configuring the measurement circuit 81 as a signal detection and display means in this way, when the electrolytic solution etc. filled in the observation section 20 in advance are pushed out of the observation section 20 as groundwater flows in, the outer electrode 11A resistance RX 11 between the inner electrode 11B and the inner electrode 11B, and the resistance RX ₁₁ between the inner electrode 11B and the center electrode 10.
Since the resistance RY ₁₁ between the two changes sequentially, this change in resistance can be interpreted as a change in the measured voltage V ₁₁ . Specifically, when substitution progresses from the outer electrode 11A toward the center electrode 10,
When the groundwater reaches the outer electrode 11A, the measured voltage V ₁₁ starts to change, and when the groundwater reaches the inner electrode 11B, the difference between the resistances RX ₁₁ and RY ₁₁ reaches its maximum and peaks, and the voltage V 11 starts to change when the groundwater reaches the inner electrode 11B. When it progresses to that point, it returns to the original value again. Therefore, the timing at which groundwater reaches the inner electrode 11B can be detected from the peak of the measured voltage _V11 . The other outer electrodes 12A to 18A and inner electrodes 12B to 18B are configured in exactly the same way as the outer electrode 11A and inner electrode 11B described above, and voltage changes are applied to each measurement electrode line group in the bridge circuit. Correspondingly, they are now being measured individually.

Next, the measurement operation of the above embodiment will be explained based on FIGS. 9 and 10.

Now, a replacement fluid 80 having electrical or chemical properties different from that of the groundwater to be measured (for example, when the conductivity of the groundwater is low,
An electrolytic solution such as a NaCl solution is used, while pure water or the like is used when underground water contains NaCl and has a relatively high conductivity. Here, we will use NaCl solution. ), and with the sleeve 51 moved to the lowest position (see Figure 4), the probe 3 is lowered to a predetermined measurement depth in the borehole 1, and then waits for the groundwater disturbance to subside. to gradually raise the sleeve 51. Then, when the sleeve 51 moves to the uppermost end, the groundwater W sequentially flows into the observation section 20 as the groundwater W flows.
NaCl solution 80 is forced to the outside. here,
For example, if we consider the case where groundwater W flows in the direction from the outer electrode 11A to 15A, first the outer electrode 11A
Since the groundwater W reaches , the voltage V ₁₁ changes first (see T ₁ in FIGS. 9A and 10). As a result, the flow direction of groundwater W is changed from the outer electrode 11A to 15A.
It is detected that the direction is . Subsequently, when the groundwater W advances to the position of the inner electrode 11B, the resistance between the outer electrode 11A and the inner electrode 11B becomes maximum, and the voltage V ₁₁ reaches its peak (see T ₃ in Figures 9B and 10). ). As the groundwater W further advances, the resistance between the inner electrode 11B and the center electrode 10 also increases, so that the pressure _V11 returns to the original level (see C in FIG. 9 and _T4 in FIG. 10). Therefore, by measuring the peak time of the voltage V ₁₁ , the timing when the groundwater W reaches the inner electrode 11B can be determined.

On the other hand, in other measurement electrode groups, for example, the measurement voltage V ₁₂ related to the bridge circuit between the outer electrode 12A, the inner electrode 12B, and the center electrode 10 is determined by the timing at which the groundwater W reaches the outer electrode 12A and the timing at which the groundwater W reaches the outer electrode 11A. Therefore, the start of change in voltage V ₁₂ is also delayed (as shown in Figure 10).
(see T ₂ ). In addition, the outer electrode 11B and the center electrode 10
Since the groundwater W diffuses and advances relatively obliquely to the direction of , the change in resistance becomes gradual.
The peak of the voltage V ₁₂ is smaller than the peak of the measured voltage V ₁₁ (see FIG. 10).

When the substitution between the groundwater W and the NaCl solution 80 progresses further and the groundwater W comes to the opposite side of the center electrode 10, the center electrode 1 in the direction of movement of the groundwater W advances.
0, the inner electrode 15B, and the outer electrode 15A, the measurement voltage V ₁₅ changes in the same manner as described above. The peak time of this voltage V ₁₅ (see FIG. 9D and T ₅ in FIG. 10) represents the timing when the leading edge of groundwater W reaches the inner electrode 15B, and the distance between the inner electrodes 11B and 15B is L
, the groundwater flow velocity can be determined from the calculation formula L/(T ₅ −T ₃ ).

According to this embodiment, the rise of the sleeve 51 is
This can be done by simply injecting pressurized water from the outside using a piston-cylinder mechanism, so there is no need for complicated structures such as extending the outer wall of the sleeve to the ground and raising it using wires, etc. It is possible to prevent erroneous operations such as entanglement of wires when the robot is moved, and to ensure upward movement. In addition, each measurement electrode 10, 11A, ..., 11B, ...
Since the structure is such that the voltage change is detected by connecting the ... with a bridge, the measurement diagram shows a peak, and therefore accurate flow measurement can be performed. moreover,
Even in re-measurement, by the action of the displacement fluid pouring mechanism 30 installed in the probe 3, the sleeve mechanism 50 is simply moved up and down by external operation while the probe 3 remains inserted into the borehole 1. This makes it possible to remeasure the groundwater W as many times as you like, which not only speeds up the measurement process, but also enables more accurate flow measurement of groundwater W. Further, in the above embodiment, since the stirring mechanism 71 is provided in addition to the observation section 20, there is an advantage that the measurement work can be speeded up, especially from the second time onwards.

In the above embodiment, pressurized water is used to raise the sleeve 51, but other means such as compressed air or pressurized oil may be used as long as they can drive the piston/cylinder mechanism. Moreover, when pulling down the sleeve, although the configuration uses the pressing force of the compression spring 64, it is also possible to use pressurized water, compressed air, or the like as long as it functions equally well. Furthermore, as the replacement fluid 80, in addition to the electrolyte, insulating oil with a high dielectric constant may be used to take advantage of the difference in capacitance with groundwater, or a liquid with a different PH value (acid or alkaline solution) may be used. and the displacement with the groundwater may be detected by an electrode for PH measurement,
Furthermore, it is possible to improve the measurement sensitivity by using a composite material mixed with metal fine particles, etc., and the key point is to improve the electrical (conductivity, inductivity, etc.) or chemical (PH, etc.) properties of the groundwater at the measurement location. Any liquid substances (including sol substances), corresponding electrodes, and measurement circuits may be used. Furthermore, the measurement electrodes may be arranged not only radially but also in a mesh pattern. Further, in the above embodiment, the case where the displacement fluid pouring mechanism 30 is used as the stirring mechanism 70 has been exemplified, but the present invention is not necessarily limited to this. It may be installed so as to be buried in the upper end portion of 8.

Next, another embodiment will be described based on FIG. 11.

In this embodiment, when replacing the groundwater in the observation section 20 with the replacement fluid in the first embodiment, the filled groundwater is first drawn out from below and moved to the upper side of the cylinder 31. be. Also, when stirring the replacement fluid, when the fluid is discharged from the head plate 7 side above the observation section 20, it is sucked in by the lower bottom plate 8 side, and on the other hand, when the fluid is discharged from the bottom plate 8 side, the upper head plate The stirring mechanism 85 is configured so as to suck in the water on the 7 side.

In this case, a porous member 8A is attached to the entire surface of the upper surface of the lower base plate 8, and an opening for the water conduit 37 described above is provided below the center of the porous member 8A. Similarly, the upper head board 7
A porous member 7A is attached to the entire surface of the lower surface of the side, and an opening for the water conduit 36 described above is provided above the center of the porous member 7A.

In this way, when the fluid inside the observation section 20 is withdrawn and discharged for its replacement and stirring, the entire fluid can be simultaneously withdrawn and discharged, and the fluid agitation inside the observation section 20 is reduced. Therefore, it is convenient because the preparation time for measurement can be shortened. The rest of the structure and operation are the same as in the previous embodiment.

〔Effect of the invention〕

Since the present invention is configured and functions as described above,
According to this, when not measuring, the observation part can be sealed by the action of the sleeve mechanism, and the sleeve mechanism maintains the sealed state of the observation part, and the liquid inside the observation part and the displacement fluid pouring mechanism is kept in a sealed state. Although it is a displacement fluid method, it has the unprecedented advantage of being able to repeatedly measure groundwater flow at the same location for a long period of time with the observation unit fixed. It is possible to provide a groundwater flow measuring device.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state in which underground water flow is measured using a probe containing a fluid flow measurement device according to the present invention, and FIG. 2 is a detailed vertical sectional view showing the probe portion of FIG. Figure 3 is the − of Figure 2.
4 to 6 are operation explanatory diagrams, FIG. 7 is a cross sectional view taken along the - line in FIG. 2, and FIG. 8 is a cross sectional view taken along the line - of FIG. Illustrative circuit diagrams, Figures 9A, B, C, D
10 is a diagram showing an example of a measurement result, and FIG. 11 is a partial sectional view showing another example. 6...Sleeve body, 10, 11A, 11B,
12A, 12B, ~18A, 18B...Measurement electrode, 20...Observation section, 30...Displacement fluid pouring mechanism, 50...Sleeve mechanism, 60...Sleeve drive unit, 71, 85...Stirring mechanism, 80 . . . Substitution fluid, 81 . . . Circuit diagram as signal detection means.

Claims (1)

[Claims] 1. An observation section in which a plurality of measurement electrodes are arranged concentrically and at predetermined intervals on the same surface at one end, and the fluid to be measured in this observation section is electrical or scientific. A probe body is provided which is equipped with a displacement fluid pouring mechanism close to the observation section for pouring out displacement fluids having different properties, and the displacement fluid is hermetically filled into the outer periphery of the observation section of the probe body as necessary. A cylindrical sleeve mechanism is equipped to be movable up and down, the displacement fluid dispensing mechanism is formed by a combination of a piston and a cylinder, and water conduit pipes are provided at one end and the other end of the cylinder, each communicating with the observation section. are installed separately, and at the end of the cylinder,
Ground water characterized by being equipped with a displacement fluid introduction pipe for introducing displacement fluid from the outside, and this displacement fluid conduit pipe being equipped with a check valve that prevents liquid from flowing out from inside the cylinder to the outside. flow measuring device.