JPS59160788A - Method and apparatus for measuring direction and velocity of flow of ground water - Google Patents

Abstract

PURPOSE:To measure direction and velocity of flow of ground water at an observation well by providing a heater and three or more temperature sensors non- linearly on the same surface of surrounding water in an observation well. CONSTITUTION:Ground water 17 is standing in an observation well about 50cm in diameter and several tens of meters deep. A detecting section 10 is fixed horizontally by a cable 18 and immersed in ground water 17. A heater 12 is provided at the center of the detecting section 10, and four temperature sensors 13- 16 are arranged at a distance of 90 deg. and at equal distance from the heater 12 in the same surface of surrounding water. Temperature information is frequency converted by an electronic circuit 19 and inputted to a signal processing device on the ground. These are protected by a reticulated sensor protector 11. Temperature of ground water is raised by the heater 12, and temperatur rise at points of specified distance is measured by sensors. Thus, direction and velocity of flow of ground water can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for measuring the flow direction and velocity of groundwater several tens of meters underground.

A conventional measurement method will be explained with reference to FIG. Figure 1 is a plan view, and 1 to 5 are observation wells.Saline water is temporarily injected into the observation well 1 located in the center, and the salinity of the water in the observation well increases over time in the surrounding observation wells 2 to 5. The flow direction and speed of groundwater was detected by examining changes.

Such conventional methods require multiple observation wells, and require injection of liquid or solid to wait for the components present inside the observation well, which may contaminate groundwater;
It has many drawbacks such as. The present invention has been made to eliminate all the drawbacks of the conventional method, and proposes an economical measurement method that is easy to handle and does not require multiple observation wells, and a groundwater current meter using the measurement method.

The present invention will be explained using FIGS. 2 and 3.

In Figure 2, groundwater 17 is stored in an observation well l several tens of meters deep, with a surface area of approximately 5 t)m. The detection part 10 is buried in groundwater 17 and fixed with a cable 18 so that the detection part 10 is horizontal.

The detection unit 10 has a heater 12 in the center, and heaters 1 are arranged around the heater 12 at 90° intervals in the same horizontal plane as the heater 12.
Four temperature sensors 13 to 16 are arranged equidistantly from the temperature sensor 2, and the four temperature sensors 13 to 16 are connected to the electronic circuit section 19 together with the heater 12, and the temperature information at each point is transmitted to the electronic circuit section 19. The signal is converted into a frequency signal by the section 19 and taken out of the observation well 1 via a cable 18, and is input to an appropriate processing device on the ground (not shown).

The surroundings of the multiplex circuit section 19 and temperature sensors 13 to 16 are protected by a cylindrical sensor protector 11, and in particular, the part of the sensor protector 11 where the vortices 1/s 13 to 16 are in the d direction is exposed to groundwater (i+t7' 1. It is constructed in a mesh-like manner to the extent that it does not interfere with ``v''f.

Next, a flow direction and flow velocity measurement method using this apparatus will be explained with reference to FIGS. 2 and 3. 1 in FIG. 3 indicates the operating state of the heater 12, and indicates that the heater 12 is operating during the period t1.

2 in FIG. 3 is a temperature sensor 14.3 is a temperature sensor 16, i
5 shows how the temperature sensor 13 and temperature sensor 15 react and change over time.

That is, the measurement is performed on the heater 12 for a time t! By increasing the temperature of the groundwater in contact with the heater 12 and calculating the temperature rise at a point a certain distance away from the heater 12, the flow velocity of the groundwater can be determined and the direction in which the groundwater 17 is flowing can be determined. If not, the four temperature sensors 13 to 16 respond to temperature changes due to heater heating in almost the same way over time, and detect the maximum temperature at t2 after energizing the heater 12.
This state of gradually decreasing thereafter is shown by the solid lines in FIGS. 3-5.

Next, apply the same fortune-telling to the heater 12 as described above. energized for a while,
When the temperature is measured by the temperature sensors 13 to 16, Fig. 3 2
A result like the dotted line of ~5 is obtained, and the temperature sensor 14.1
6. The time when 13 and 15 reached the highest temperature is t31t41tl after energizing the heater 12, respectively! % and t6 (this time is determined by the above-mentioned signal processing device on the ground) ○ Each temperature sensor 13 to 16 is
The distance from
On the other hand, the flow velocity υ is or + try' %, and its direction is
Expressed as an angle with the axis, it is θ-jan 1, and by substituting the above two relationships into these equations, the flow velocity and flow direction of groundwater can be determined.

In the above embodiment, four temperature +w sensors are provided, f'C, ri1
j is shown, but it can be measured if there are three or more. Also,
Regarding the measurement method, the entire measurement method of the present invention can be carried out by using only one temperature sensor and measuring the groundwater temperature at three or more locations by changing the position of this temperature sensor. According to the invention, the flow direction and velocity of groundwater can be measured with a single observation well, the observation cost can be significantly reduced, and there are advantages such as almost no influence on the quality of groundwater. The effect is extremely significant.

[Brief explanation of the drawing]

FIG. 1 is for illustration purposes only and shows a plurality of observation wells. FIGS. 2 and 3 are for explaining the present invention; FIG. 2 shows the configuration of the detection section, and FIG. 3 is a graph showing the measurement results. 1. Observation well 10... Detection section 12...
- Heater 13-16...Temperature sensor. Agent Teru Taniyama Yuji Mi-2 Procedural Amendment Document Showa Gus Parallel JM Application No. M-2-7 No. 3, Relationship with the person making the amendment “l f'l” Applicant 4, Agent Address: 2-6-2 Marunouchi, 2-6-2, Fyo 1t1-ku, Tokyo Shigesu Building 330 - Right → 廿 - Eleventh Amendment The following matters in the specification of this application are amended. Notes 1 and 1 On the 4th to 3rd lines from the bottom of page 2, the statement "The detection unit 10 is..." is corrected to "The detection unit 10 is buried in the groundwater 17, and J." 2. From No. 3 to 6 In the first line, ``1 in Figure 3'' is corrected to ``(1) in Figure 3''. 3. In the third line from the bottom of the third page, ``2...3 in Figure 3 is j'' is changed to ``(2 in Figure 3)''.
) is corrected as temperature sensor 14, and (3) is corrected as j. 4. In the second line from the bottom of page 3, "4 is ... and 5 is ko" is corrected to "(4) is temperature sensor 13, and (5) is 1." 5. Minoh page 4 In lines 11 and 144, “2-5” should be corrected as “(2)-(5)” respectively. 6. On page 5, line 3, “X-axis 1” should be changed to “X-axis 1”. Correct. 7. In the 4th line of page 5, correct [?/Axis 1] to ``Y-axis.'' 1:, -, -, :'a

Claims (1)

[Claims] 1. Heating one point in the groundwater and measuring temperature changes in the groundwater at three or more locations around the heating point that are separated from the heating point and in a non-linear arrangement relationship. Due to the flow direction,
A method for measuring the flow velocity of underground water, characterized by measuring the flow velocity. 2 In a device that measures the flow direction and velocity of ground water, three or more temperature key sensors set in a non-linear manner in the same horizontal plane and a heater placed inside the area surrounded by the three or more temperature sensors. A device for measuring groundwater flow direction and velocity.