CN112880861A - High-precision surface temperature measuring device and measuring method thereof - Google Patents

Abstract

The invention relates to the technical field of temperature measuring devices, in particular to a high-precision earth surface temperature measuring device and a measuring method thereof, wherein the temperature measuring device comprises a fixing mechanism and a temperature measuring mechanism; the fixing mechanism comprises a plastic pipe, at least one temperature measuring mechanism is sleeved outside the plastic pipe, the temperature measuring mechanism comprises a metal pipe and an optical fiber, the metal pipe is fixedly sleeved outside the plastic pipe, the optical fiber is wound on the metal pipe, and grid points on the optical fiber are adhered to the metal pipe through glue. The high-precision superficial layer earth surface temperature measuring device provided by the invention has the advantages of simple structure, low cost, easiness in installation and suitability for popularization and use; the method has the outstanding advantages of high sensitivity, high reliability, electromagnetic interference resistance, good safety, quasi-distributed real-time measurement, high precision and the like, is a promotion and supplement for the existing shallow geothermal monitoring technology, and has very important significance for promoting the study of shallow geothermal energy.

Description

High-precision surface temperature measuring device and measuring method thereof

Technical Field

The invention relates to the technical field of temperature measuring devices, in particular to a high-precision earth surface temperature measuring device and a measuring method thereof.

Background

The shallow geothermal energy is a novel, high-quality and reproducible clean energy source, and has the advantages of energy conservation and emission reduction, wide distribution, huge reserves, rapid regeneration, strong availability, high safety and the like. The evaluation research of the shallow geothermal energy resource potential and the influence factors thereof has great significance for understanding the reserves and the distribution of the regional shallow geothermal energy and the popularization and the application of the ground source heat technology, not only can provide decision basis for the planning and development of the shallow geothermal energy of government related departments, provide key reference indexes for the evaluation of the regional shallow geothermal energy resource potential, but also provide basis for the reasonable design and construction of ground source hot springs, provide reference for the utilization and the design optimization of the shallow geothermal energy according to local conditions, avoid the blind unreasonable development, and ensure the scientificity, rationality and reliability of the shallow geothermal energy development.

The potential of shallow geothermal energy resources and the influence factors thereof are researched, firstly, the distribution rule and the influence factors of a shallow geothermal field are researched, the shallow underground rock +/-body original temperature field is monitored, and further the rationality of development and utilization of the shallow geothermal energy is analyzed. At present, the conventional method for monitoring the shallow geothermal field is to put a U-shaped or single temperature sensor into a borehole, and common sensors comprise a conventional sensor and a fiber grating sensor. The conventional sensors mainly comprise Pt100 and iButton, are metal sensors, are buried underground for a long time, and are easy to corrode and damage. The fiber bragg grating sensor has the advantages of being distributed, single-ended in detection, long in distance, good in durability, strong in interference resistance, strong in implantability, simple and convenient to operate and the like, and comprises distributed temperature measurement optical fibers (DTS) and Fiber Bragg Gratings (FBGs), but the temperature measurement accuracy of the DTS and the FBGs is only 0.4 ℃ and 0.1 ℃, so that the application provides the high-precision earth surface temperature measuring device and the measuring method thereof.

Disclosure of Invention

In order to solve the technical problems, the invention provides a high-precision earth surface temperature measuring device and a measuring method thereof.

The invention provides the following technical scheme:

a high-precision earth surface temperature measuring device comprises a fixing mechanism and a temperature measuring mechanism; the fixing mechanism comprises a plastic pipe, at least one temperature measuring mechanism is sleeved outside the plastic pipe, the temperature measuring mechanism comprises a metal pipe and an optical fiber, the metal pipe is fixedly sleeved outside the plastic pipe, the optical fiber is wound on the metal pipe, and grid points on the optical fiber are adhered to the metal pipe through glue.

Preferably, the fixing mechanism comprises a screw, and the metal tube is fixed on the plastic tube by at least one screw.

Preferably, the device further comprises a protection mechanism, and the protection mechanism is sleeved outside the metal pipe.

Preferably, the outer diameter of the plastic tube is larger than the outer diameter of the metal tube.

Preferably, the glue is epoxy resin glue.

Preferably, the protection mechanism is a PVC reducer union.

Preferably, a dedicated optical fibre protective sleeve is secured between two of said protective mechanisms. Use the PVC reducing joint to protect in the outside, use special optic fibre protection sheath to the FBG optic fibre between the PVC reducing joint to protect, can freely adjust the length of whole device according to the degree of depth of shallow geothermal testing.

Preferably, the metal pipe is a copper pipe, an aluminum pipe or an iron pipe.

Preferably, the optical fiber is a DTS fiber and a FBG fiber.

A measuring method of a high-precision earth surface temperature measuring device comprises the following steps:

s1: monitoring the depth of the shallow geothermal temperature according to the requirement to drill;

s2: the assembled device is vertically lowered into the borehole, and the device is prevented from bending in the process;

s3: after the device is placed at the bottom of the drill hole, protecting the lead part of the hole opening, and detecting whether a loop is communicated by using a red light pen;

s4: backfilling the drilled hole after the preliminary test of the optical cable is finished;

s5: the optical fiber is connected to the fiber grating demodulator, so that the device can be monitored in real time, and high-precision shallow geothermal data can be acquired.

The invention relates to a high-precision surface temperature measuring device and a measuring method thereof, which have the beneficial effects that the high-precision superficial surface temperature measuring device is simple in structure, low in cost, easy to install and suitable for popularization and use; the method has the outstanding advantages of high sensitivity, high reliability, electromagnetic interference resistance, good safety, quasi-distributed real-time measurement, high precision and the like, is a promotion and supplement for the existing shallow geothermal monitoring technology, and has very important significance for promoting the study of shallow geothermal energy.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a cross-sectional view of a high-precision shallow surface temperature measuring device according to the present invention;

FIG. 2 is a partial cross-sectional view of a high-precision shallow surface temperature measuring device according to the present invention;

FIG. 3 is a diagram of calibration parameters of the shallow surface temperature measurement device of example 1;

reference numerals: 1. a plastic tube; 2. a special optical fiber protective sheath; 3. a PVC reducer union; 4. a metal tube; 5. screw, 6, optical fiber.

Detailed Description

The conception, the specific structure and the technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings to fully understand the objects, the schemes and the effects of the present invention. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. Further, the description of the upper, lower, left, right, etc. used in the present invention is only with respect to the positional relationship of the respective components of the present invention with respect to each other in the drawings.

As shown in fig. 1 to 2, a high-precision earth surface temperature measuring device comprises a fixing mechanism and a temperature measuring mechanism; the fixing mechanism comprises a plastic pipe 1 and a screw 5, at least one temperature measuring mechanism is sleeved outside the plastic pipe 1 and comprises a metal pipe 4 and an optical fiber 6, the metal pipe 4 is fixedly sleeved outside the plastic pipe 1, the optical fiber 6 is wound on the metal pipe 4, and grid points on the optical fiber 6 are adhered to the metal pipe 4 through glue. The metal pipe 4 is fixed on the plastic pipe 1 through at least one screw 5, the PVC reducing joint 3 is sleeved outside the metal pipe 4, and the special optical fiber protective sleeve 2 is fixed between the two PVC reducing joints 3. The PVC reducer joints 3 are used for protection at the outer sides, the optical fibers 6 among the PVC reducer joints 3 are protected by the special optical fiber protection sheaths 2, and the length of the whole device can be freely adjusted according to the depth of shallow geothermal testing.

Example 1:

a high-precision earth surface temperature measuring device comprises a fixing mechanism and a temperature measuring mechanism; fixing mechanism includes the plastic tubing, at least one temperature measurement mechanism cup joints outside of the tubes the plastic tubing, temperature measurement mechanism includes copper pipe and FBG optic fibre, the copper pipe is through four the screw fixation cup joints outside of the tubes the plastic tubing, FBG optic fibre winding is in on the copper pipe, the bars point on the FBG optic fibre is glued through epoxy glue on the copper pipe.

Shallow layer ground temperature changes and leads to the breathing of copper pipe, and the FBG optic fibre of winding on the copper pipe surface can the breathing of perception copper pipe, shows on the change of grating point wavelength on the FBG optic fibre. The temperature change conditions of all parts of the shallow geothermal field are monitored in real time by monitoring the wavelength change of the FBG optical fiber. The measurement of the higher thermal expansion coefficient of copper pipe and a plurality of FBG fiber grating points on single copper pipe can effectively improve the monitoring precision of shallow geothermal temperature.

A measuring method of a high-precision earth surface temperature measuring device comprises the following steps:

s1: monitoring the depth of the shallow geothermal temperature according to the requirement to drill;

s2: the assembled device is vertically lowered into the borehole, and the device is prevented from bending in the process;

s3: after the device is placed at the bottom of the drill hole, protecting the lead part of the hole opening, and detecting whether a loop is communicated by using a red light pen;

s4: backfilling the drilled hole after the preliminary test of the optical cable is finished;

s5: the optical fiber is connected to the fiber grating demodulator, so that the device can be monitored in real time, and high-precision shallow geothermal data can be acquired.

Example 2:

a high-precision earth surface temperature measuring device comprises a fixing mechanism and a temperature measuring mechanism; the fixing mechanism comprises a plastic pipe, at least one temperature measuring mechanism is sleeved outside the plastic pipe, the temperature measuring mechanism comprises an aluminum pipe and a DTS optical fiber, the aluminum pipe is fixedly sleeved outside the plastic pipe through four screws, the DTS optical fiber is wound on the aluminum pipe, and grid points on the DTS optical fiber are adhered to the aluminum pipe through epoxy resin glue. The PVC reducing joint is sleeved outside the aluminum pipe, and the special optical fiber protective sleeve is fixed between the two PVC reducing joints.

A measuring method of a high-precision earth surface temperature measuring device comprises the following steps:

s1: monitoring the depth of the shallow geothermal temperature according to the requirement to drill;

s2: the assembled device is vertically lowered into the borehole, and the device is prevented from bending in the process;

s3: after the device is placed at the bottom of the drill hole, protecting the lead part of the hole opening, and detecting whether a loop is communicated by using a red light pen;

s4: backfilling the drilled hole after the preliminary test of the optical cable is finished;

s5: the optical fiber is connected to the fiber grating demodulator, so that the device can be monitored in real time, and high-precision shallow geothermal data can be acquired.

Example 3:

a high-precision earth surface temperature measuring device comprises a fixing mechanism and a temperature measuring mechanism; fixing mechanism includes the plastic tubing, at least one temperature measurement mechanism cup joints outside of the tubes plastic tubing, temperature measurement mechanism includes iron pipe and FBG optic fibre, the iron pipe is through four the screw fixation cup joints outside of the tubes plastic tubing, FBG optic fibre winding is in on the iron pipe, the bars point on the FBG optic fibre passes through epoxy glue and glues on the iron pipe. The PVC reducing joint is sleeved outside the iron pipe, and the special optical fiber protective sleeve is fixed between the two PVC reducing joints.

A measuring method of a high-precision earth surface temperature measuring device comprises the following steps:

s1: monitoring the depth of the shallow geothermal temperature according to the requirement to drill;

s2: the assembled device is vertically lowered into the borehole, and the device is prevented from bending in the process;

s3: after the device is placed at the bottom of the drill hole, protecting the lead part of the hole opening, and detecting whether a loop is communicated by using a red light pen;

s4: backfilling the drilled hole after the preliminary test of the optical cable is finished;

s5: the optical fiber is connected to the fiber grating demodulator, so that the device can be monitored in real time, and high-precision shallow geothermal data can be acquired.

As shown in fig. 3, it is evident that the temperature change and the wavelength change of the grating point of the FBG fiber in the calibration test in embodiment 1 show perfect linear change along with the temperature increase, the data is stable, and the monitoring precision of the grating point wavelength can reach 1pm (10 pm)^-12m), the monitoring precision of the temperature can reach 0.013 ℃, and the feasibility and the superiority of the high-precision superficial layer earth surface temperature measuring device provided by the invention are verified.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A high-precision earth surface temperature measuring device is characterized by comprising a fixing mechanism and a temperature measuring mechanism; the fixing mechanism comprises a plastic pipe, at least one temperature measuring mechanism is sleeved outside the plastic pipe, the temperature measuring mechanism comprises a metal pipe and an optical fiber, the metal pipe is fixedly sleeved outside the plastic pipe, the optical fiber is wound on the metal pipe, and grid points on the optical fiber are adhered to the metal pipe through glue.

2. The high-precision earth surface temperature measuring device according to claim 1, wherein the fixing mechanism comprises screws, and the metal tube is fixed on the plastic tube through at least one screw.

3. The high-precision earth surface temperature measuring device according to claim 1, further comprising a protection mechanism, wherein the protection mechanism is sleeved outside the metal pipe.

4. The high accuracy earth surface temperature measuring device of claim 1, wherein the outer diameter of the plastic tube is larger than the outer diameter of the metal tube.

5. The high-precision earth surface temperature measuring device according to claim 1, wherein the glue is epoxy resin glue.

6. The high-precision earth surface temperature measuring device according to claim 3, wherein the protection mechanism is a PVC reducer union.

7. A high-precision earth surface temperature measuring device according to claim 3 or 6, characterized in that a special optical fiber protective sleeve is fixed between the two protection mechanisms.

8. The high-precision earth surface temperature measuring device according to any one of claims 1 to 6, wherein the metal pipe is a copper pipe, an aluminum pipe or an iron pipe.

9. The high-precision earth surface temperature measuring device according to any one of claims 1 to 6, wherein the optical fiber is a DTS optical fiber and a FBG optical fiber.

10. The method for measuring the high-precision earth surface temperature measuring device according to any one of claims 1 to 9, which is characterized by comprising the following steps:

s1: monitoring the depth of the shallow geothermal temperature according to the requirement to drill;

s2: the assembled device is vertically lowered into the borehole, and the device is prevented from bending in the process;

s3: after the device is placed at the bottom of the drill hole, protecting the lead part of the hole opening, and detecting whether a loop is communicated by using a red light pen;

s4: backfilling the drilled hole after the preliminary test of the optical cable is finished;

s5: the optical fiber is connected to the fiber grating demodulator, so that the device can be monitored in real time, and high-precision shallow geothermal data can be acquired.

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