CN202393687U - Water supply network pipeline resistance coefficient testing device - Google Patents

Abstract

The utility model relates to a water supply network pipeline resistance coefficient testing arrangement, including pipe-line system, pressure test module, flow test module and control system, pipe-line system is including being responsible for section, branch pipe section, preceding fire hydrant, well fire hydrant, back fire hydrant pressure test module includes pressure sensor, pressure sensor installs in the front on the fire hydrant in the middle of the fire hydrant be responsible for being equipped with back control flap in the section be equipped with preceding control flap in the branch pipe section, pressure test module is connected with control system through an interface converter, flow test module includes ultrasonic flowmeter, ultrasonic flowmeter installs on the fire hydrant of back ultrasonic flowmeter control system is inside to be equipped with one set of intelligent recording system. The utility model discloses improving measurement accuracy, having had very big progress in the aspect of quick accurate record and high-efficient processing data etc, for the accurate determination of pipeline resistance coefficient provides more perfect method, promoted the development of water supply network pipeline resistance actual measurement technique.

Description

Water supply network pipe resistance coefficient test device

technical field

The utility model belongs to the technical field of environmental engineering, in particular to a test device for resistance coefficient of a water supply pipe network. the

Background technique

After years of operation of the water supply pipe network, due to the corrosion of the inner wall of the pipe, microbial adhesion, deposition and other reasons, the cross-sectional area of the water in the pipe has been continuously reduced, and the head loss has increased, which seriously affects the flow capacity of the pipe. Therefore, a more accurate grasp of the water flow capacity of key pipe sections in the water supply network is of great significance for establishing a simulation model of the water supply network and realizing safe and rational operation of the water supply network. However, due to the long running time and long history of laying in the actual water supply pipe network, the resistance coefficients of different pipes are quite different. Existing data and codes can only give the resistance coefficient value of the new pipeline, which cannot accurately reflect the actual operation of the pipeline. At present, domestic scholars have done many theoretical studies on the determination of pipeline resistance coefficient, such as: "two-point method", "three-point method" and so on. However, there are few studies on the measuring device for the resistance coefficient of the water supply pipe network, and there is no relatively mature measuring device for the resistance coefficient of the pipeline. the

For the determination of the resistance coefficient of domestic pipelines, some domestic companies and scientific research institutions have used the obtained pipe wall slices to obtain the absolute roughness coefficient of the pipe wall by measuring methods such as vernier calipers to obtain the specific resistance of various pipe materials and different ages. Due to the rough surface of the pipe wall, its size, shape, height, density, and arrangement are changing along the pipe, unless a section of the pipe wall with sufficient pipe length is obtained, and there is a correct scientific measurement of the irregular shape and arrangement of protrusions Or post-conversion method, otherwise the accuracy of this manual measurement method is difficult to guarantee. the

There are currently four different methods for on-site testing of pipeline friction, namely: two-point method, three-point method, four-point method, and five-point method. In actual engineering, we can choose a test method that meets the local actual conditions for on-site testing based on the site of the test site and the specific conditions of the pipeline accessories. Among them, the two-point method is the most basic method and the most commonly used method for measuring pipeline resistance designed by using the hydraulic pipeline specific resistance formula. the

(1) Two-point method

In actual engineering, the "two-point method" is usually used to measure the friction coefficient of pipelines. That is to test the head loss and pipeline flow on a section of pipeline, and calculate the specific resistance K value of the pipeline through formula 3-2. the

The formula for calculating the pipeline resistance is: $K=\frac{\mathrm{\Δh}/l}{Q^{\mathrm{\α}}}$

so: $K=\frac{(h_1-h_2)/l}{Q^{\mathrm{\α}}}$

If the factor of ground elevation is considered, the formula becomes: $K=\frac{(z_1+h_1-z_2-h_2)/l}{Q^{\mathrm{\α}}}$

In the formula: H ₁ , H ₂ —— water pressure at the test point (m);

l——the distance between H ₁ and H ₂ (m);

z ₁ , z ₂ —— ground elevation of pressure measuring point (m);

Q——the flow rate in the pipeline (m ³ /s);

α——exponent value, take 1.852. the

The "two-point method" has a clear principle and requires less on-site data. When conditions permit, using this method is the most convenient and quickest method of actual measurement among all methods. the

(2) Three-point method

On the premise of the same pipe diameter, same pipe material, and pipe section of the same laying age, a field measurement method of "three-point method" was proposed,

After considering the factors of ground elevation, the calculation formula is:

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{{<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}}{\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}$

In the formula, H ₁ , H ₂ , H ₃ —— water pressure at the test point (m);

l ₁ , l ₂ ——the distance between H ₁ , H ₂ and H ₂ , H ₃ (m)

z ₁ , z ₂ , z ₃ ——the ground elevation of the three pressure measuring points (m);

α——exponent value, take 1.852. the

This method overcomes the shortcoming of needing to measure the flow of the main pipe, but in practical applications, due to the simultaneous existence of pressure measurement and flow measurement at the second point, the pressure relief at this point is serious, which interferes with the measurement data of the pressure measurement point. the

(3) Four-point method

The "four-point method" is to take 4 points on the same straight pipeline, of which 3 points are used for pressure measurement and 1 point is used for flow measurement. The schematic diagram is shown in the figure below. Utilizing this method can effectively avoid the phenomenon that both flow and pressure are measured in the middle, which makes the pressure measurement in this place abnormal. the

After considering the factors of ground elevation, the formula is transformed into:

$\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{{<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}}{\mathrm{<span\; class="notranslate">\; q</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}$

In the formula:

H ₁ , H ₂ , H ₃ ——water pressure at the test point (m);

l ₁ , l ₂ , l ₃ ——the distance between H ₁ , H ₂ and H ₂ and the flow point, and between the flow point and H ₃ (m)

z ₁ , z ₂ , z ₃ ——the ground elevation of the three pressure measuring points (m);

α——exponent value, take 1.852. the

To sum up, the "two-point method" test principle is relatively simple. Although the "three-point method" and "four-point method" are improved on the basis of the "two-point method", the test process is more complicated, and the test site conditions Often difficult to achieve, due to the complexity of the test process, it often causes more test errors, so it is not often used. the

Contents of the invention

The utility model overcomes the deficiencies of the prior art and proposes a test device for the resistance coefficient of the water supply pipe network. Point method” and developed a test device for the resistance coefficient of the water supply pipe network. The device takes the absolute pressure of two adjacent fire hydrants on the measured pipeline as the core, measures the head loss of the straight pipe section between the two adjacent fire hydrants, and uses the fire hydrant discharge method to measure the flow of the pipe section with a high-precision ultrasonic flowmeter, and then Through analysis and calculation, the resistance coefficient of the measured pipe section is obtained. In the process of measuring the resistance coefficient of the pipeline, the device effectively avoids the error caused by the measurement of the differential pressure meter, greatly improves the measurement accuracy, and is relatively simple and convenient to operate. Large areas without water for a long time. Using this device to test the pipe resistance coefficient of the water supply pipe network not only provides a data basis for the simulation modeling of the water supply pipe network, but also provides technical support for the water company to grasp the flow capacity of key water supply pipe sections, so as to carry out scientific management of the water supply pipe network . the

The technical solution of the utility model is: a water supply pipe network pipeline resistance coefficient test device, including a pipeline system, a pressure test module, a flow test module and a control system, the pipeline system includes a main pipe section, a branch pipe section, a front fire hydrant, a middle fire hydrant, a rear The fire hydrant and the pressure test module include a pressure sensor, the pressure sensor is installed on the front fire hydrant and the middle fire hydrant, the rear control valve is provided on the main pipe section, and the front control valve is provided on the branch pipe section. The pressure test module is connected with the control system through an interface converter, the flow test module includes an ultrasonic flowmeter, and the ultrasonic flowmeter is installed on the rear fire hydrant, and a set of intelligent recording system is arranged inside the control system. the

The branch pipe section communicates with the main pipe section through pipe fittings. the

The front fire hydrant communicates with the main pipe section through pipe fittings. the

The intermediate fire hydrant communicates with the main pipe section through pipe fittings. the

The rear fire hydrant communicates with the main pipe section through pipe fittings. the

The interface converter is an RS485 converter. the

The utility model has the following beneficial effects:

1. The absolute pressure of the fire hydrant of the measured pipeline is measured by a high-precision pressure sensor, which effectively reduces the system error caused by using a U-shaped differential pressure gauge to measure the resistance coefficient of the pipeline in the past. the

2. During the measurement process, the developed automatic recording system is used to automatically record the measured pressure value, effectively avoiding the error caused by manual recording; and the pressure change curve can be drawn in real time, and the pressure change law during the test process can be observed. The data processing efficiency is high, and it can be adjusted in time when problems are found. the

3. The independent fire hydrant downstream of the pressure measuring fire hydrant on the measured pipeline is used for flow test, which effectively avoids the interference caused by the pressure measurement during the discharge process of the fire hydrant. the

4. High-precision pressure sensor is used to measure the pipeline flow in a non-contact manner, which avoids pipeline excavation and has high measurement accuracy. the

5. It is not necessary to accurately measure the burial depth of the pipeline. It is only necessary to measure the ground elevation where the pressure measuring fire hydrant is located and the height of the hydrant to obtain a more accurate measurement of the head loss of the pipe section, and then obtain the pipeline resistance coefficient. the

6. Great progress has been made in reducing manpower, shortening installation and commissioning time, improving measurement accuracy, fast and accurate recording and efficient data processing, etc. It provides a relatively complete method for the accurate determination of pipeline resistance coefficient and promotes the water supply network. Development of pipeline resistance measurement technology. the

Description of drawings

Further illustrate the utility model below in conjunction with accompanying drawing and specific embodiment. the

Accompanying drawing is the schematic diagram of principle of the utility model. the

In the figure, 1. Front fire hydrant; 2. Pressure sensor; 3. Shielded signal line; 4. Interface converter; 5. Control system; 6. Middle fire hydrant; 7. Rear fire hydrant; 8. Ultrasonic flowmeter; 9. Rear control Valve; 10. Main pipe section; 11. Front control valve; 12. Branch pipe section. the

Detailed ways

The following will be further described in conjunction with the accompanying drawings, but not to limit the scope of the present utility model. the

Referring to the accompanying drawings, the utility model includes a pipeline system, a pressure test module, a main pipe section 10, a flow test module and a control system 5. A branch pipe section 12 is provided on the main pipe section 10, and a front pipe section 12 is provided on the branch pipe section 12. After the control valve 11 is installed and debugged, the utility model can carry out resistance coefficient test, pressure test and flow test. The pressure test and flow test need to be measured at the same time. The test method is:

(1) Stress test

The pressure test module uses the pressure sensor 2 for absolute pressure test, which can output 4-20mA or 0-10V signal, and the analog value of the measured value is transmitted to the control system 5 through the 4-core shielded signal line 3 and the interface converter, and the interface is converted The device 4 is usually an RS485 converter, and a set of intelligent recording system is arranged inside the control system 5 . The intelligent recording system includes READ30 software, which can store signals and graphics on the control system 5, and can measure up to one hundred and twenty-eight pressure sensors 2, while using the bus mode for communication. During the measurement, two pressure sensors 2 were installed at the water outlets of the front fire hydrant 1 and the rear fire hydrant 7, and the valves of the front fire hydrant 1 and the rear fire hydrant 7 should all be opened. During the test, through the self-developed intelligent recording system, The control system 5 can simultaneously record two sets of pressure test data, and users can set the data recording frequency according to their own needs, and draw pressure change curves in real time. This system is conducive to discovering on-site operation problems and correcting them at any time, which improves the accuracy of the test. the

(2) Flow test

The flow test module uses a high-precision portable ultrasonic flowmeter 8 for pipe flow test. During the test, the rear control valve 9 and the front control valve 11 at the downstream end of the test pipe section are closed. The flow test can be carried out at the middle fire hydrant 6 or the front fire hydrant 1. Here, it is recommended to conduct the flow test at the rear fire hydrant 7, which can avoid the disturbance of the water flow to the pressure test of the middle fire hydrant 6, and the flow state is relatively stable, so as to reduce the system test error. During the test, gradually open the valve of the rear fire hydrant 7 until the opening reaches 100%. After the system stabilizes, record the water outlet flow and the absolute pressure at the front fire hydrant 1 and middle fire hydrant 6 under different valve opening conditions. This device uses a non-contact method to measure the flow rate. The pressure loss is small and the structure is simple. The detector is installed on the outside of the pipeline, which does not require excavation, does not damage the pipeline, and has high measurement accuracy. The high-precision portable ultrasonic flowmeter 8 needs to meet the following conditions at the same time when it is installed and tested on site:

① The ultrasonic flowmeter 8 must have a suitable installation position, mainly to facilitate the horizontal installation of the operator;

②The site needs 220v working power supply;

③ The detection point is used as the collimation pipe section to meet the following requirements on site, 10D upstream and 5D downstream (D is the straight path of the pipeline);

④ On-site pipeline material and wall thickness, whether the inner wall of the pipeline is lined and the type of lining;

⑤Two installation options: Z-type and V-type, Z-type installation is mainly used;

⑥Ultrasonic working state: the normal working state is displayed as R;

⑦Ultrasonic signal strength: It is normal to meet 1.8, the greater the signal strength, the higher the measurement stability;

⑧Compare the ultrasonic flowmeter with the on-site flowmeter. The on-site flowmeter needs to have instantaneous flow and cumulative flow display. the

(3) Drag coefficient test

When using this device to test the resistance coefficient of the water supply pipe network, the ground elevation of the front fire hydrant 1 and the middle fire hydrant 6, the height of the fire hydrant opening, and the distance between the front fire hydrant 1 and the middle fire hydrant 6 should also be measured, and the pressure test should be carried out After the flow and flow tests, using the test results, it is easy to use the formula of the two-point method to calculate the resistance coefficient of the measured pipeline. the

Claims (6)

1. water supply network resistance of ducting coefficient testing device; Comprise piping system, pressure test module, flow rate test module and control system; Said piping system comprises main leg, a pipeline section, preceding hydrant, middle hydrant, back hydrant, and it is characterized in that: said pressure test module comprises pressure transducer, and said pressure transducer is installed on preceding hydrant and the middle hydrant; On said main leg, be provided with the back by-pass valve control; On said pipeline section, be provided with preceding by-pass valve control, said pressure test module is connected with control system through an interface convertor, and said flow rate test module comprises ultrasonic flow meter; Said ultrasonic flow meter is installed on the hydrant of back, is provided with the intelligent register system of a cover in said control system inside.

2. water supply network resistance of ducting coefficient testing device according to claim 1 is characterized in that: said pipeline section is connected with the main leg through pipe fitting.

3. water supply network resistance of ducting coefficient testing device according to claim 1 and 2 is characterized in that: hydrant is connected with the main leg through pipe fitting before said.

4. water supply network resistance of ducting coefficient testing device according to claim 3 is characterized in that: hydrant is connected with the main leg through pipe fitting in said.

5. water supply network resistance of ducting coefficient testing device according to claim 4 is characterized in that: said back hydrant is connected with the main leg through pipe fitting.

6. water supply network resistance of ducting coefficient testing device according to claim 4 is characterized in that: said interface convertor is the RS485 converter.