A non-contact inspection well water level measuring device and use method

Abstract

The present invention provides a non-contact inspection well water level measuring device, including an outer ring and an inner ring, and a plurality of connecting rods for connecting the outer ring and the inner ring, a plurality of horizontal adjustment mechanisms are arranged at intervals at the bottom of the outer ring; a liquid level meter is arranged in the inner ring; a power supply, an RTK antenna and a tape measuring mechanism are also arranged on the connecting rod; the tape measuring mechanism includes a bracket, a laser rangefinder and a rotating shaft installed on the bracket; the rotating shaft is connected to the rocker, and a tape measure is coaxially wound on the rotating shaft; a hanging plate is connected to the end of the tape measure, the hanging plate has buoyancy, and the upper surface is coated with a highly reflective material; the present invention also provides a method for using the aforementioned non-contact inspection well water level measuring device. The benefits of the present invention are: by pulling away the tape measure, it can be judged whether the hanging plate reaches the water surface, and finally the rough measurement of the water surface can be achieved; the hanging plate reaching the water surface provides an effective reflection plane for the laser rangefinder, so as to achieve the liquid level measurement of the laser rangefinder.

Description

Technical Field

[0001] The invention relates to the technical field of inspection well measurement, and in particular to a non-contact inspection well water level measuring device and a use method thereof. Background Art

[0002] Manhole water level measurement is of great significance in the fields of municipal engineering and environmental engineering. It plays an important role in leak detection of pipeline networks and monitoring of pipeline siltation. However, the existing manhole water level measurement technology still has certain errors.

[0003] Non-contact distance measuring devices often use ultrasonic, electromagnetic or laser rangefinders for measurement. Among them, the measurement of water level by ultrasonic and electromagnetic level gauges is calculated based on the ground elevation of the inspection well, the distance between the liquid surface and the probe, and the distance between the probe and the ground. Water level = ground elevation - distance between the probe and the ground - distance between the liquid surface and the probe. Due to the characteristics of high temperature, high humidity, and strong convection of domestic sewage, the measurement of ultrasonic probes lacks the correction function for temperature, humidity, and airflow, and the existing temperature correction probes are arranged around the ultrasonic probes, which cannot reflect the temperature and humidity differences under different well depth conditions during the propagation of sound waves. Excessive temperature and humidity faults can also cause reflections of ultrasonic and even electromagnetic waves, thereby causing water level measurement deviations. In addition, due to the problem of the minimum emission angle of ultrasonic and electromagnetic wave measuring instruments, the beam will be refracted multiple times on the deep wellbore, forming measurement noise and affecting the measurement accuracy. The laser rangefinder has better light beam parallelism, but due to irregular mirror reflections on the water surface, the laser rangefinder can easily receive light signals reflected from the mirror onto the wall of the inspection well, resulting in measurement deviations. It may also cause measurement failure because the light fails to enter the sensor after mirror reflection on the water surface.

[0004] In order to reduce the error of water level measurement caused by the complex internal environment of the pipe in the sewer system and to better monitor the liquid level in the inspection well stably, a new type of non-contact inspection well water level measurement device is urgently needed. Summary of the invention

[0005] The purpose of the present invention is to provide a non-contact inspection well water level measuring device to solve the problems existing in the prior art.

[0006] The invention provides a non-contact inspection well water level measuring device, comprising an outer ring and an inner ring which are arranged concentrically, and a plurality of connecting rods for connecting the outer ring and the inner ring, wherein the outer diameter of the outer ring is larger than the diameter of the manhole cover of the inspection well, and a plurality of level adjustment mechanisms are arranged at intervals at the bottom of the outer ring for helping the outer ring to maintain levelness; a liquid level meter is arranged in the inner ring, and the measurement origin of the liquid level meter is flush with the upper surface of the connecting rod; the invention also comprises a power supply, an RTK antenna and a tape measuring mechanism arranged on the same or different connecting rods, and the RTK antenna is used to measure the elevation of the upper surface of the connecting rod; the tape measuring mechanism comprises a bracket, a laser rangefinder and a rotating shaft installed on the bracket, and the center line of the laser rangefinder is parallel to the axis of the rotating shaft; the rotating shaft is connected to a rocker, and a tape measure is coaxially wound on the rotating shaft, and the tape measure can be lowered or retracted by rotating the rocker; a hanging plate is connected to the end of the tape measure, and the hanging plate has buoyancy and the upper surface is coated with a high-reflective material; the power supply is used to power the RTK antenna, the laser rangefinder and the liquid level meter.

[0007] Preferably, the level adjustment mechanism comprises a knob, an adjusting screw and a foot which are sequentially arranged from top to bottom, the adjusting screw passes through the outer ring and is threadedly connected to the outer ring, and a bubble level is embedded in the knob.

[0008] Preferably, an inner ring sleeve is provided inside the inner ring, and the liquid level meter is installed in the inner ring sleeve.

[0009] Preferably, the liquid level meter is an ultrasonic liquid level meter probe or an electromagnetic wave liquid level meter probe.

[0010] Preferably, it also includes a guide tube, the air inlet of which is connected to the wind source, and an air inlet bracket is provided at the bottom to stabilize the air inlet; the air outlet of the guide tube is connected to the outer ring; the inner diameter of the guide tube gradually increases along the air inlet toward the air outlet.

[0011] Preferably, the wind source is a silent fan.

[0012] The present invention also provides a method for using the aforementioned non-contact inspection well water level measuring device, comprising the following steps:

[0013] The distance between the zero scale of the tape measure and the bottom of the hanging plate is recorded as D1, and then the tape measure is installed on the rotating shaft, and the distance between the rotating shaft and the upper surface of the connecting rod is recorded as D2; adjust the horizontal adjustment mechanism to keep the outer ring horizontal, and then turn the rocker to lower the tape measure, so that the hanging plate at the end of the tape measure drops; when the tension on the tape measure suddenly decreases, the hanging plate has contacted the water surface in the inspection well. At this time, the operator's line of sight is in line with the center line of the laser rangefinder and the rotating shaft, and the scale D3 on the tape measure where the tension mutation point is located is read; calculate D3+D1-D2 to obtain the rough distance L1 between the upper surface of the connecting rod and the water surface;

[0014] Record the distance between the laser rangefinder and the upper surface of the connecting rod as D4, then turn on the laser rangefinder and confirm that the laser point is on the upper surface of the hanging plate; then put the guide tube on the outer ring to ensure that the air inlet is stable and the outer ring remains horizontal; turn on the air source and send dry and clean air into the inspection well. After the laser rangefinder reading is stable, read the degree D5 of the laser rangefinder. Calculate D5-D4 to get the precise distance L2 between the upper surface of the connecting rod and the water surface;

[0015] According to the reflection angle α of the level gauge, determine the relationship between tan(α / 2)*L1 and the radius of the inspection well, and determine whether diffuse reflection will occur;

[0016] If tan(α / 2)*L1 is greater than the radius of the inspection well, remove the guide tube and the measurement ends;

[0017] If tan(α / 2)*L1 is smaller than the radius of the inspection well, a level gauge can be used for precise measurement. In this case, first remove the guide tube, turn the rocker to retract the tape measure, so that the hanging plate rises, and remove the tape measure and the hanging plate; then put on the guide tube to ensure that the air inlet is stable and the outer ring remains horizontal; turn on the air source to send dry and clean air into the inspection well, and then turn on the level gauge. After the level gauge reading stabilizes, read the level gauge to obtain the precise distance L3 between the upper surface of the connecting rod and the water surface;

[0018] Compare the difference between L1 and L2 / L3. If the difference between L1 and L2 / L3 is less than 5%, L2 or (L2+L3) / 2 is used as the liquid level depth L4. If the difference between L1 and L2 / L3 is greater than 5%, L1 is used as the liquid level depth L4.

[0019] Turn on the RTK antenna, measure the elevation L5 of the upper surface of the connecting rod, and obtain the liquid level value of the inspection well as L5-L4.

[0020] The present invention is beneficial in that:

[0021] 1) Use the interconnected tape measure and hanging plate, and judge whether the hanging plate reaches the water surface by pulling away the tape measure, so as to finally achieve the rough measurement of the water surface;

[0022] 2) Combined with the rough measurement results of the ruler, according to the emission angle of the current level meter, calculate whether diffuse reflection will occur, affecting the measurement accuracy;

[0023] 3) The hanging plate reaching the water surface provides an effective reflection plane for the laser rangefinder to realize the liquid level measurement of the laser rangefinder;

[0024] 4) Integrated RTK antenna to comprehensively calculate the liquid level in the inspection well;

[0025] 5) Add a deflector cover and a fan to introduce dry and clean gas into the inspection well to ensure consistent temperature and humidity inside the well, optimize the temperature and humidity correction effect, eliminate the temperature and humidity fault, and prevent signal reflection and liquid level mismeasurement caused by the temperature and humidity fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a bottom view of the non-contact inspection well measuring device of the present invention;

[0027] Figure 2 is a side view of the non-contact inspection well measuring device of the present invention;

[0028] Figure 3 It is a bottom view of the non-contact inspection well measuring device of the present invention in a state of preparing for measuring;

[0029] Figure 4 It is a side view of the non-contact inspection well measuring device of the present invention in a state of preparing for measuring;

[0030] Figure 5 It is a bottom view of the non-contact inspection well measuring device of the present invention in a measuring state;

[0031] Figure 6 It is a side view of the non-contact inspection well measuring device of the present invention in the measuring state.

[0032] Component number description:

[0033] 1 Outer ring

[0034] 2 Outer ring wall

[0035] 3 Knobs

[0036] 4 Adjusting screw

[0037] 5. Stepping

[0038] 6 Upper reinforcement

[0039] 7 Lower reinforcement rib

[0040] 8 Inner Ring

[0041] 9 Inner ring sleeve

[0042] 10 Connecting rod

[0043] 11 Power Supply

[0044] 12 Support rods

[0045] 13 RTK Antenna

[0046] 14 Bracket

[0047] 15. Laser rangefinder

[0048] 16 Axis

[0049] 17 Joystick

[0050] 18. Tape measure

[0051] 19 Suspension tray

[0052] 20 Liquid level gauge

[0053] 21. Guide tube

[0054] 22 Air Inlet

[0055] 23 Air inlet bracket

[0056] 24 Air inlet support feet DETAILED DESCRIPTION

[0057] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0058] In the description of the present invention, it should be noted that the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0059] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0061] like Figure 1-4 As shown, the present invention provides a non-contact inspection well water level measuring device, including an outer ring 1 and an inner ring 8 arranged concentrically, and a plurality of connecting rods 10 for connecting the outer ring 1 and the inner ring 8. The number of connecting rods 10 is preferably four, and the four connecting rods 10 are distributed in a cross shape, which can effectively strengthen the structural strength of the device in the horizontal direction. The outer diameter of the outer ring 1 is larger than the diameter of the manhole cover of the inspection well, and a plurality of level adjustment mechanisms are arranged at intervals at the bottom thereof to help the outer ring 1 to maintain level. Specifically, the level adjustment mechanism includes a knob 3, an adjusting screw 4 and a foot 5 arranged in sequence from top to bottom, the adjusting screw 4 passes through the outer ring 1 and is threadedly connected to the outer ring 1, and a bubble level is embedded in the knob 3. By twisting the knob 3, the screw 4 can be driven to rise and fall, so as to adjust the level of the outer ring 1. A circle of outer ring wall 2 extending upward is also provided along the circumference of the outer ring 1, and the outer ring wall 2 is used to be sleeved with the subsequent guide tube 21.

[0062] An inner ring sleeve 9 is provided on the inner side of the inner ring 8, and a liquid level meter 20 is installed in the inner ring sleeve 9. The liquid level meter 20 is an ultrasonic liquid level meter probe or an electromagnetic wave liquid level meter probe. The measurement origin of the liquid level meter 20 is flush with the upper surface of the connecting rod 10, which is convenient for subsequent calculations. The inner ring 8 can strengthen the structural strength of the device in the vertical direction and support the inner ring sleeve 9. An upper reinforcing rib 6 is provided between the outer ring wall 2 and each connecting rod 10, and a lower reinforcing rib 7 is provided between the inner ring 8 and each connecting rod 10. The upper reinforcing rib 6 and the lower reinforcing rib 7 can increase the bending resistance of the device.

[0063] The device also includes a power supply 11, an RTK antenna 13 and a tape measuring mechanism. When considering the installation positions of these components, each component can be set on a different connecting rod 10 as in a specific embodiment of the present invention to prevent the device from tipping over due to the shift in the center of gravity. Alternatively, two or three of the components can be set on the same connecting rod 10 as needed. Among them, the RTK antenna 13 is installed on the connecting rod 10 through a support rod 12, and is used to measure the elevation of the upper surface of the connecting rod 10. The tape measuring mechanism includes two brackets 14 installed on the connecting rod 10, a laser rangefinder 15 and a rotating shaft 16 respectively installed on the two brackets 14, and the center line of the laser rangefinder 15 is parallel to the axis of the rotating shaft 16. The rotating shaft 16 is connected to a rocker 17, and a tape measure 18 is coaxially wound on the rotating shaft 16. By rotating the rocker 17, the tape measure 18 can be lowered or retracted. A hook is provided at the end of the tape measure 18 for connecting to a hanging plate 19. The suspension plate 19 has buoyancy and is coated with a highly reflective material on its upper surface, which can provide an effective reflection plane for the laser rangefinder 15 to help the laser rangefinder 15 to achieve accurate liquid level measurement. The power supply 11 is used to power the RTK antenna 13, the laser rangefinder 15, and the liquid level meter 20.

[0064] In order to ensure that the temperature and humidity in the inspection well are consistent, there is no temperature and humidity mutation section, optimize the temperature and humidity correction effect, and thus ensure the accuracy of the measurement, the non-contact water level measurement device of the present invention also includes the following Figure 5 and Figure 6 The guide tube 21 shown, the air inlet 22 of the guide tube 21 is connected to the wind source, and the wind source is preferably a silent fan. An air inlet bracket 23 is provided at the bottom of the air inlet 22, and an air inlet support foot 24 is provided at the bottom of the air inlet bracket 23. The air inlet bracket 23 and the air inlet support foot 24 can help stabilize the air inlet 22 and weaken the vibration effect of the air inlet 22. The air outlet of the guide tube 21 is connected with the outer ring wall 2 of the outer ring 1. The inner diameter of the guide tube 21 gradually increases from the air inlet 22 to the air outlet direction, and a bending portion is provided between the air inlet 22 and the air outlet. Such an arrangement can reasonably arrange the installation space while facilitating the loading and unloading of the guide tube 21. Preferably, the power supply 11 and the air inlet bracket 23 and the air inlet support foot 24 are arranged in different directions of the device, so that the center of the device can be balanced and the device can be prevented from being skewed.

[0065] The present invention also provides a method for using the aforementioned device, comprising the following steps:

[0066] The distance between the zero scale of the tape measure 18 and the bottom of the hanging plate 19 is recorded as D1, and then the tape measure 18 is installed on the rotating shaft 16, and the distance between the rotating shaft 16 and the upper surface of the connecting rod 10 is recorded as D2; the horizontal adjustment mechanism is adjusted to keep the outer ring 1 horizontal, and then the rocker 17 is rotated to lower the tape measure 18, so that the hanging plate 19 at the end of the tape measure 18 is lowered; when the tension on the tape measure 18 suddenly decreases, it means that the hanging plate 19 has contacted the water surface in the inspection well. At this time, the operator's line of sight is in line with the center line of the laser rangefinder 15 and the rotating shaft 16, and the scale D3 on the tape measure 18 where the tension mutation point is located is accurately read; D3+D1-D2 is calculated to obtain the rough distance L1 between the upper surface of the connecting rod 10 and the water surface;

[0067] The distance between the laser rangefinder 15 and the upper surface of the connecting rod 10 is recorded as D4, then the laser rangefinder 15 is turned on to confirm that the laser point is located on the upper surface of the hanging plate 19; then the guide tube 21 is put on the outer ring 1 to ensure that the air inlet 22 is stable, and the movement amplitude during this installation process should be as small as possible to keep the outer ring 1 horizontal; turn on the wind source to send dry and clean air into the inspection well, and after the reading of the laser rangefinder 15 is stable, read the degree D5 of the laser rangefinder 15. Calculate D5-D4 to obtain the precise distance L2 between the upper surface of the connecting rod 10 and the water surface;

[0068] According to the reflection angle α of the level gauge 20, determine the relationship between tan(α / 2)*L1 and the radius of the inspection well, and determine whether diffuse reflection will occur;

[0069] If tan(α / 2)*L1 is larger than the radius of the inspection well, the level meter 20 cannot be used for precise measurement. In this case, the guide tube 21 can be removed to end the measurement. Compare the difference between L1 and L2. If the difference between L1 and L2 is less than 5%, L2 is used as the liquid level depth L4. If the difference between L1 and L2 is greater than 5%, L1 is used as the liquid level depth L4. Turn on the RTK antenna 13, measure the elevation L5 of the upper surface of the connecting rod 10, and obtain the liquid level value of the inspection well as L5-L4.

[0070] If tan(α / 2)*L1 is smaller than the radius of the inspection well, the level gauge 20 can be used for precise measurement. At this time, first remove the guide tube 21, turn the rocker 17 to retract the tape measure 18, so that the hanging plate 19 rises, and remove the tape measure 18 and the hanging plate 19; then put the guide tube 21 on the outer ring wall 2 to ensure that the air inlet 22 is stable and the outer ring 1 remains horizontal; turn on the air source to send dry and clean air into the inspection well, and then turn on the level gauge 20. After the reading of the level gauge 20 is stable, read it. Take the liquid level meter 20 and obtain the precise distance L3 between the upper surface of the connecting rod 10 and the water surface; compare the difference between L1 and L2, L3. If the difference between L1 and L2, L3 is less than 5%, (L2+L3) / 2 is used as the liquid level depth L4; if the difference between L1 and L2 / L3 is greater than 5%, L1 is used as the liquid level depth L4; turn on the RTK antenna 13, measure the elevation L5 of the upper surface of the connecting rod 10, and obtain the liquid level value of the inspection well as L5-L4.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A non-contact inspection well water level measuring device, characterized in that: It comprises an outer ring (1) and an inner ring (8) which are arranged concentrically, and a plurality of connecting rods (10) for connecting the outer ring (1) and the inner ring (8). The outer diameter of the outer ring (1) is larger than the diameter of the manhole cover of the inspection well, and a plurality of level adjustment mechanisms are provided at intervals at the bottom thereof to help the outer ring (1) maintain a level state; A liquid level gauge (20) is provided inside the inner ring (8), and a measurement origin of the liquid level gauge (20) is flush with the upper surface of the connecting rod (10); The invention also comprises a power supply (11), an RTK antenna (13) and a tape measure mechanism which are arranged on the same or different connecting rods (10), wherein the RTK antenna (13) is used to measure the elevation of the upper surface of the connecting rod (10); the tape measure mechanism comprises a bracket (14), a laser rangefinder (15) and a rotating shaft (16) which are installed on the bracket (14), wherein the center line of the laser rangefinder (15) is parallel to the axis of the rotating shaft (16); the rotating shaft (16) is connected to a rocker (17), and a tape measure (18) is coaxially wound on the rotating shaft (16), and the tape measure (18) can be lowered or retracted by rotating the rocker (17); the end of the tape measure (18) is connected to a hanging plate (19), wherein the hanging plate (19) has buoyancy and the upper surface is coated with a highly reflective material; the power supply (11) is used to supply power to the RTK antenna (13), the laser rangefinder (15) and the liquid level meter (20).

2. The non-contact inspection well water level measuring device according to claim 1 is characterized in that: The level adjustment mechanism comprises a knob (3), an adjustment screw (4) and a foot (5) which are arranged in sequence from top to bottom; the adjustment screw (4) passes through the outer ring (1) and is threadedly connected to the outer ring (1); and a bubble level is embedded in the knob (3).

3. The non-contact inspection well water level measuring device according to claim 1 is characterized in that: An inner ring sleeve (9) is arranged inside the inner ring (8), and the liquid level meter (20) is installed in the inner ring sleeve (9).

4. The non-contact inspection well water level measuring device according to claim 1 or 3, characterized in that: The liquid level meter (20) is an ultrasonic liquid level meter probe or an electromagnetic wave liquid level meter probe.

5. The non-contact inspection well water level measuring device according to claim 1 is characterized in that: It also comprises a guide tube (21), the air inlet (22) of the guide tube (21) being connected to a wind source, and an air inlet bracket (23) being provided at the bottom for stabilizing the air inlet (22); the air outlet of the guide tube (21) being connected to the outer ring (1); and the inner diameter of the guide tube (21) gradually increases along the air inlet (22) towards the air outlet.

6. The non-contact inspection well water level measuring device according to claim 5 is characterized in that: The wind source is a silent fan.

7. A method for using the non-contact inspection well water level measuring device as claimed in claim 5, characterized in that: The following steps are involved: The distance between the zero scale of the measuring tape (18) and the bottom of the hanging plate (19) is recorded as D1, and then the measuring tape (18) is installed on the rotating shaft (16), and the distance between the rotating shaft (16) and the upper surface of the connecting rod (10) is recorded as D2; the horizontal adjustment mechanism is adjusted so that the outer ring (1) remains horizontal, and then the rocker (17) is rotated to lower the measuring tape (18), so that the hanging plate (19) at the end of the measuring tape (18) is lowered; when the tension on the measuring tape (18) is suddenly reduced, the hanging plate (19) has contacted the water surface in the inspection well, and at this time, the operator's line of sight is collinear with the center line of the laser rangefinder (15) and the rotating shaft (16), and the scale D3 on the measuring tape (18) where the tension mutation point is located is read; D3+D1-D2 is calculated to obtain the rough distance L1 between the upper surface of the connecting rod (10) and the water surface; The distance between the laser rangefinder (15) and the upper surface of the connecting rod (10) is recorded as D4, and then the laser rangefinder (15) is turned on to confirm that the laser point is located on the upper surface of the hanging plate (19); then the guide tube (21) is put on the outer ring (1) to ensure that the air inlet (22) is stable and the outer ring (1) remains horizontal; the air source is turned on to send dry and clean air into the inspection well, and after the reading of the laser rangefinder (15) is stable, the degree D5 of the laser rangefinder (15) is read; Calculate D5-D4 to obtain the precise distance L2 between the upper surface of the connecting rod (10) and the water surface; According to the reflection angle α of the level meter (20), the relationship between tan(α / 2)*L1 and the radius of the inspection well is determined, and whether diffuse reflection will occur; If tan(α / 2)*L1 is greater than the radius of the inspection well, remove the guide tube (21) and the measurement is completed; compare the difference between L1 and L2, if the difference between L1 and L2 is less than 5%, L2 is used as the liquid level depth L4; if the difference between L1 and L2 is greater than 5%, L1 is used as the liquid level depth L4; turn on the RTK antenna (13), measure the elevation L5 of the upper surface of the connecting rod (10), and obtain the liquid level value of the inspection well as L5-L4; If tan(α / 2)*L1 is less than the radius of the inspection well, the level gauge (20) is used for precise measurement. At this time, the guide tube (21) is first removed, and the rocker (17) is turned to retract the tape measure (18), so that the hanging plate (19) rises, and the tape measure (18) and the hanging plate (19) are removed; then the guide tube (21) is put on, and the air inlet (22) is ensured to be stable and the outer ring (1) is kept horizontal; the air source is turned on to send dry and clean air into the inspection well, and then the level gauge (20) is turned on, and the reading of the level gauge (20) is stable. After the determination, read the liquid level meter (20) to obtain the precise distance L3 between the upper surface of the connecting rod (10) and the water surface; compare the difference between L1 and L2, L3. If the difference between L1 and L2, L3 is less than 5%, (L2+L3) / 2 is used as the liquid level depth L4; if the difference between L1 and L2, L3 is greater than 5%, L1 is used as the liquid level depth L4; turn on the RTK antenna (13), measure the elevation L5 of the upper surface of the connecting rod (10), and obtain the liquid level value of the inspection well as L5-L4.

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