CN102269770A - Stick for gauging flow velocity of optical fibers - Google Patents

Abstract

The invention relates to an optical fiber flow rate detection rod, which comprises a ruler body with a scale, a handle is arranged on the upper end of the ruler body, a circular level is arranged on the upper end of the handle, and an optical fiber grating measuring rod capable of moving up and down along the ruler body is arranged on the ruler body. device. After the optical fiber flow velocity detection rod is placed in the drainage pipe or open channel, the orientation device can automatically adjust the velocity measurement direction of the element, the optical fiber measurement element monitors the water flow velocity, and the scale body shows the water level of the measuring point and the depth of the drainage ditch. There is a certain difference in the water flow velocity at different water levels, so the main body of the sliding measurement part is used for multi-point measurement. Calculate the flow rate of the drainage pipe or open channel from the water level of the measuring point, the water passing area and the water flow velocity of each measuring point, so as to obtain the water inflow of the fissure.

Description

An optical fiber flow velocity detection rod

the

technical field

The invention relates to an instrument for measuring the flow velocity of different water levels in drainage pipes or open channels, in particular to an optical fiber flow velocity detection rod. the

Background technique

At present, the construction of underground projects such as long tunnels, subways, hydropower stations, iron mines, and coal mines is booming in my country, but water inrush accidents often occur, causing a large number of casualties and economic losses. Part of the reason for this is that the monitoring of mine or tunnel drainage is not in place, and there is a lack of effective flow rate monitors to accurately measure the water inflow from cracks. the

Monitoring the liquid flow rate of the drainage ditch, the water level of the monitoring point and the depth of the drainage ditch can finally accurately obtain the flow rate of the gushing water, which can effectively solve the above problems. However, the existing flow rate monitors are relatively large in size, and it is easy to change the flow field, resulting in inaccurate measurement parameters. Accurate, and it is impossible to measure in small cracks. In addition, existing flow rate monitors still have shortcomings such as poor pressure resistance and waterproof ability, inability to realize multi-measurement point measurement, poor leveling ability, etc., and there is still a lot of room for improvement. the

Fiber Bragg grating sensing principle description:

As shown in Figure 10, a fiber grating is a spatial phase grating whose refractive index is periodically distributed along the fiber axis by using a certain method to permanently change the refractive index of the fiber core. A fiber grating is a section of optical fiber with a structure in which the refractive index changes periodically in its core.

Compared with traditional sensors, fiber optic sensors have the following advantages:

(l) High sensitivity;

(2) Passive devices have no effect on the measured object;

(3) The optical fiber is a dielectric, high pressure resistant, corrosion resistant, safe and reliable in flammable and explosive environments;

(4) Frequency bandwidth, large dynamic range;

(5) The geometric shape has various adaptability, and can be made into sensors and sensor arrays of any shape;

(6) Sensors that sense different physical quantities can be made on the basis of a common technology;

(7) It can cooperate with optical fiber telemetry technology to realize long-distance measurement and control;

(8) The fiber optic sensor system composed of fiber optic sensors is convenient to connect with the central computer to meet the requirements of multi-function and intelligence;

(9) The sensor is small in size and light in weight.

Contents of the invention

The object of the present invention is to provide an optical fiber flow velocity detection rod in order to overcome the above-mentioned deficiencies in the prior art. the

To achieve the above object, the present invention adopts the following technical solutions:

An optical fiber flow rate detecting rod comprises a ruler body with scale, a handle is arranged on the upper end of the ruler body, a circular level is arranged on the upper end of the handle, and an optical fiber grating measuring device capable of moving up and down along the ruler body is arranged on the ruler body.

The fiber grating measuring device includes a fixing device, a fiber grating measuring meter and an orientation device, the fixing device is connected to the ruler body, the fiber grating measuring meter is connected to the fixing device, and the orientation device is connected to the fiber grating measuring meter connected. the

The fixing device includes a connecting rod and a collar, one end of the collar is connected to the connecting rod, and the other end is fastened and nested on the ruler through a nut. the

The fiber grating measuring meter includes a measuring meter housing, on which a rotatable housing is arranged, and the rotatable housing is connected with the fixing device. the

The rotatable housing is rotatably connected with the measuring meter housing through several ball rollers. the

The orientation device includes a rod body connected to the housing, and at least one plate-shaped body is connected to the end of the rod body.

There are two sheet-like bodies, one end of both of which is connected to the rod body, and the two have an included angle. the

The bottom end of the ruler body is also provided with a tray. the

The ruler body is composed of a plurality of sub-ruler bodies connected by threads, and the handle and the ruler body are connected by threads. the

The optical signal transmission line drawn out by the fiber grating measuring instrument is arranged in parallel with the ruler body through the optical signal transmission line fixing groove arranged on the ruler body. the

After the optical fiber flow velocity detection rod is placed in the drainage pipe or open channel, the orientation device can automatically adjust the velocity measurement direction of the element, the optical fiber measurement element monitors the water flow velocity, and the scale body displays the water level of the measuring point and the depth of the drainage ditch. There is a certain difference in the water flow velocity at different water levels, so the main body of the sliding measurement part is used for multi-point measurement. Calculate the flow rate of the drainage pipe or open channel from the water level of the measuring point, the water passing area and the water flow velocity of each measuring point, so as to obtain the water inflow of the fissure. the

Compared with other flow rate monitoring instruments, the optical fiber flow rate detection rod of the present invention has the following significant technical advantages and characteristics:

(1) The measurement accuracy is high, and the high sensitivity can be achieved by using the fiber grating sensing principle, which effectively improves the accuracy of the measurement data;

(2) Simple structure, convenient processing and high cost performance;

(3) Adopt single-rod design, which can realize multi-measuring point measurement;

(4) Detachable and easy to carry;

(5) Good waterproof and compressive performance;

(6) Equipped with a speed measuring element orientation device to improve measurement accuracy;

(7) While measuring the flow rate, the water level of the monitoring point and the depth of the drainage ditch can also be measured at the same time.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the side view of ruler body part;

Fig. 3 is the overall plan view of detection rod;

Figure 4 is a side view of the fixture;

Figure 5 is a top view of the fixture;

Figure 6 is a side view of the orientation device;

Figure 7 is a top view of the orientation device;

Fig. 8 is a cross-sectional view of the fiber grating meter;

Fig. 9 is a schematic diagram of the principle of use of the detection rod;

Figure 10 is a schematic diagram of fiber grating sensing.

Among them: 1. Circular level, 2. Handle, 3. Ruler body, 4. Optical signal transmission line fixing groove, 5. Plug, 6. Fixing device, 7. Optical fiber grating measuring instrument, 8. Measuring head, 9. Protective cover , 10. Orientation device, 11. Optical signal transmission line, 12. Tray, 13. Tapered rubber film, 14. Measuring meter housing, 15. Cantilever beam, 16. Measuring grating, 17. Ball roller, 18. End cover, 19. Fixed metal sheet, 20. Target sheet, 21. Photoelectric signal conversion device, 22. Data analysis computer, 23. Optical signal transmission, 24 Electrical signal transmission, 25. Other detection rods. the

Detailed ways

The present invention will be further elaborated below through specific examples. It should be noted that the following descriptions are only for explaining the present invention, and do not limit its content. the

As shown in Figure 1, an optical fiber flow rate detection rod for measuring liquid flow rate and flow rate is composed of a circular level 1, a handle 2, a scale body 3, an optical signal transmission line 11, a fixing groove 4, a plug 5, a pincer It consists of a fixing device 6, a fiber grating measuring meter 7, a measuring head 8, a protective cover 9, an orientation device 10, an optical signal transmission line 11 and a bottom rubber tray 12. the

As shown in Figure 2, the ruler body 3 is composed of two sections of the ruler body and the handle 2 through threaded connections, and the handle 2 and the ruler body 3 are also connected by threads, and each section of the ruler body and the ruler The threads between the body and the handle 2 are the same, and the scales between the ruler bodies match in turn, so the handle 2 can be removed and connected to each section of the ruler body respectively, so as to measure water levels at different depths. According to the representation in Fig. 2, the handle 2 is connected to the ruler body in the middle of the figure, and the ruler body is connected to the ruler body on the right side, and the fixed thread structure is shown in the circle in Fig. 2 . The ruler body 3 is designed as three parts, when the depth of the groove is less than 0.8 meters, the handle 2 and the lower section bar can be combined to measure, and the three parts are used together when the depth of the groove is greater than 0.8 meters. The ruler body 3 is also provided with a fixing groove 4 for the optical signal transmission line, which is convenient for the optical signal transmission line 11 to be stuck in the fixing groove. the

As shown in Fig. 1 and Fig. 3, a handle 2 is provided on the upper end of the ruler body 3, and a circular level 1 is provided on the upper end of the handle 2, and the circular level 1 can conveniently ensure the verticality of the rod. the

As shown in Figure 1, the bottom of the ruler body 3 is provided with a rubber tray 12 to prevent the ruler body 3 from sinking excessively at the bottom of the ditch due to its own weight when the instrument is measuring. the

As shown in FIG. 1 , a fiber grating measuring device capable of moving up and down along the ruler body 3 is also provided on the ruler body 3 . The fiber grating measuring device includes a fixing device 6, a fiber grating measuring gauge 7 and an orientation device 10, the fiber grating measuring gauge 7 is connected to the fixing device 6, and the orientation device 10 is connected to a measuring body. As shown in Figures 4 and 5, the fixing device 6 is a pincer-shaped fixing device, which includes a connecting rod and a collar, the collar is composed of two semicircular rings, and the collar is nested in the ruler body 3, and one end is connected to the connecting rod, and the other end is fastened by a nut. The fixing device 6 can move up and down on the scale body 3 . the

As shown in Figure 8, the fiber grating meter 7 includes a meter housing 14, the upper part of the meter housing 14 is provided with a groove, and three layers of ball rollers 17 are arranged in the groove, and the housing can be rotated Outside the ball rollers 17, the rotatable housing is rotatably connected to the meter housing 14 through several ball rollers 17. Therefore, the measuring body (excluding the part of the rotatable housing) of the fiber grating measuring instrument 7 and the orientation device 10 can rotate together under the force of the water flow, and the ball roller 17 plays a role in reducing frictional resistance. the

As shown in FIG. 6 and FIG. 7 , the orientation device 10 includes a rod body connected (can be welded together) to the measuring meter housing 14 , and two vertically arranged sheet bodies are also connected to the end of the rod body. One ends of the two sheet-shaped bodies are connected to the rod body, and the two form an included angle of 20°. When manually orienting the measuring head toward the direction of water flow, the orientation device 10 and the rotatable fiber grating measuring gauge 7 (relative to the rotatable housing, the fiber grating measuring gauge 7 is rotatable) can make the measuring direction accurate under the action of water flow change. the

As shown in FIG. 8 , one end of the meter housing 14 of the fiber grating meter 7 is connected to an end cover 18 . A fixed metal sheet 19 is installed on the end cover 18, and the fixed metal sheet 19 is connected to the cantilever beam 15. The cantilever beam 15 is provided with a measuring grating 16, and the measuring grating 16 is connected to an optical fiber. The optical fiber passes through the end cover 18 and is transmitted through an optical signal. Line 11 is connected to plug 5 . The end of the cantilever beam 15 is provided with a metal target 20, and the target 20 is to be exposed to the water flow. In order to protect the target 20 when the measuring rod is not in use at ordinary times, the inventor has also designed a detachable protective cover 9 outside the metal target 20. , and the protective cover 9 is unplugged during measurement. The lower end of the fiber grating measuring instrument 7 is a measuring head, and the measuring head includes the lower end of the cantilever beam 15 and the target sheet 20 . A conical rubber membrane 13 is also provided on the cantilever beam 15 , one end of the conical rubber membrane 13 is connected to the meter housing 14 , and the other end is sleeved on the cantilever beam 15 and sealed. The optical signal transmission line 11 drawn from the fiber grating measuring instrument 7 is arranged in parallel with the ruler body 3 through the optical signal transmission line 11 fixing groove 4 provided on the ruler body 3 . the

The measuring grating 16 is a double fiber grating, and they are symmetrically pasted in the middle of both sides of the cantilever beam 15 . For details, please refer to the patent CN101995485A, which is named "Target Fiber Bragg Grating Velocimeter". the

As shown in Figure 9, the signal measured by the optical fiber flow velocity depth measuring rod of the present invention is passed to the photoelectric signal conversion device 21 through the optical signal transmission 23, and the electrical signal conversion device can be connected to multiple other depth measuring rods 25 at the same time, through the electrical signal conversion The electrical signal transmission 24 processed by the device is sent to the data analysis computer 22 for analysis. the

Innovation:

1. The optical fiber flow rate detection rod adopts the principle of fiber grating sensing, which has the advantages of high precision, strong noise resistance, and waterproof. For details, please refer to the description of the principle of fiber grating sensing;

2. Adopt single-rod design, in which the monitoring element can move up and down freely on the rod marked with the scale by means of the card slot, so as to realize the measurement of liquid flow rate at multiple measuring points;

3. Small size, convenient and fast disassembly and assembly, can be used in experiments and engineering applications to monitor the flow rate of slurry in tiny cracks or ditches;

4. It has additional functions such as monitoring the water level of the measuring point and the depth of the drainage ditch;

5. Equipped with the speed measuring element orientation device 10, which can automatically adjust the best direction of the element to measure the flow velocity, so as to make the measurement result more accurate.

Claims (10)

1. A kind of optical fiber velocity detecting rod, it is characterized in that, it comprises the chi body with scale, and the upper end of chi body is provided with handle, and the upper end of handle is provided with circular level, and chi body is also provided with and can move up and down along chi body Fiber Bragg grating measurement device. 2. A kind of fiber optic flow rate detection rod according to claim 1, characterized in that, the fiber grating measuring device comprises a fixing device, a fiber grating measuring meter and an orientation device, the fixing device is connected with the ruler body, and the The fiber grating measuring meter is connected with the fixing device, and the orientation device is connected with the fiber grating measuring meter. 3. A kind of optical fiber flow rate detection rod according to claim 2, characterized in that, the fixing device comprises a connecting rod and a collar, one end of the collar is connected to the connecting rod, and the other end is tightened by a nut. Nested firmly on the ruler body. 4. A fiber optic flow velocity detection rod according to claim 2, characterized in that, the fiber grating measuring instrument comprises a measuring instrument housing, the measuring instrument housing is provided with a rotatable housing, and the rotatable housing connected to the fixture. 5 . The optical fiber flow velocity detection rod according to claim 4 , wherein the rotatable housing is rotatably connected to the measuring meter housing through a plurality of ball rollers. 6 . 6 . The optical fiber flow velocity detection rod according to claim 2 , wherein the orientation device comprises a rod body connected to the housing, and at least one sheet-shaped body is connected to the end of the rod body. 7 . 7 . The optical fiber flow velocity detection rod according to claim 6 , wherein there are two sheet-shaped bodies, one end of both of which is connected to the rod body, and the two have an included angle. 8 . 8 . The fiber optic flow velocity detection rod according to claim 1 , wherein a tray is provided at the bottom end of the blade. 8 . 9 . The optical fiber flow velocity detection rod according to claim 1 , wherein the ruler body is composed of a plurality of subscale bodies connected by threads, and the handle and the ruler body are connected by threads. 10 . 10. A fiber optic flow velocity detection rod according to claim 1, characterized in that the optical signal transmission line drawn from the fiber grating measuring meter is arranged in parallel with the ruler body through the optical signal transmission line fixing groove arranged on the ruler body together.

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