CN213022232U - Experimental table capable of measuring water hammer pressure wave velocity of different pipes under multiple working conditions - Google Patents
Experimental table capable of measuring water hammer pressure wave velocity of different pipes under multiple working conditions Download PDFInfo
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- CN213022232U CN213022232U CN202022483228.4U CN202022483228U CN213022232U CN 213022232 U CN213022232 U CN 213022232U CN 202022483228 U CN202022483228 U CN 202022483228U CN 213022232 U CN213022232 U CN 213022232U
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Abstract
The utility model provides a different tubular product water hammer pressure ripples velocity of wave laboratory bench under measurable multiplex condition, belongs to check out test set technical field. The high-level water tank, the water pump and the ground water tank are all connected in series on a closed loop pipeline, and at least one replacement pipe is arranged in the closed loop pipeline and is in pipeline loose joint with the closed loop pipeline through two clamp type loose joints. And the high-level water tank supplies water to the closed-loop pipeline and the ground water tank in a stable pressure manner, and performs related water hammer experiments of reservoir water supply. The water supply is provided for a closed-loop pipeline and a ground water tank through a water pump, and the water supply device is used for a pump-stopping water hammer and an upstream valve-closing transient flow experiment. And when a water flowing pipe is connected outside the closed loop circuit, performing a downstream valve closing water hammer experiment. And a three-way pipe is connected to the downstream of the closed-loop pipeline, the solenoid valve seven is arranged on the rest branch pipe on the three-way pipe, and the solenoid valve seven is used for connecting an exhaust valve. The utility model discloses can set up the experimental work condition of multiple difference correspondingly according to different experiment places, can satisfy the demand in various experiment places basically.
Description
Technical Field
The utility model belongs to the technical field of check out test set, especially, relate to a water hammer pressure ripples speed laboratory bench.
Background
The pressure pipelines for urban water supply, heat supply, gas supply and the like are life lines for ensuring normal life of people, but hydraulic accidents often occur in the conveying process of the pipelines, wherein the water hammer phenomenon which can cause the damage of the pipelines and pipe fittings is more prominent. The generation of water hammer is often accompanied by the sudden increase or decrease of pressure in the pipeline and periodically propagates along the pipeline, so that the pipeline body can vibrate and be accompanied by noise, and if the vibration occurs at a weak part of the pipeline wall or a firm supporting point outside the pipeline, the pipeline is easy to break. In addition, when the pressure in the pipeline is greatly reduced, gas in water can be separated out, gas-liquid two-phase flow can occur in the pipeline, cavitation can occur in some parts of the pipeline, and a water hammer can be closed by flow cutoff in severe cases. The generation of water hammer can cause damage to the pipeline, and can also cause damage to hydraulic equipment in the pipeline system, for example, the water pressure is too high, so that a valve or a water pump can be damaged, engineering accidents are caused, and the life and property safety of people is endangered.
In order to better prevent the damage of the pipeline and the pipe fittings, at the beginning of the design of the pipeline system, the prediction and analysis are needed according to the parameters of the pressure wave velocity of the water hammer appearing in the pipeline, the maximum and minimum pressure and the like, thereby ensuring the safety and the reliability of the pipeline system. In recent years, the mixed pipeline system with the elastic steel pipe and various other types of pipelines coexisting is gradually replacing the pipeline system made of a single material, compared with the traditional elastic steel pipe, the wave velocity of the water hammer pressure wave of the pipeline system is different, and the difference between the wave velocity of the pressure wave of the pipe obtained by theoretical analysis and the actual engineering is larger. The existing pipeline water hammer pressure wave velocity detection device is essentially based on an ultrasonic wave velocity testing device, can only detect a single type of pipeline and pipeline working conditions, and is complex to operate. Therefore, it is necessary to design a test bench which is simple to operate and can measure the wave velocity of water hammer pressure waves of different pipes under multiple working conditions.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a different tubular product water hammer pressure ripples speed laboratory bench under measurable multiplex condition for solve above-mentioned problem.
The utility model adopts the technical proposal that: a test bench capable of measuring water hammer pressure wave velocity of different pipes under multiple working conditions comprises a ground water tank, a solenoid valve seven, a water pump, a high-level water tank, a closed-loop pipeline and a water flowing pipe; the high-level water tank, the water pump and the ground water tank are all connected in series on a closed loop pipeline, at least one replacement pipe is arranged in the closed loop pipeline and is in pipeline loose joint with the closed loop pipeline through two clamp type loose joints, and the high-level water tank supplies water to the closed loop pipeline and the ground water tank in a stable pressure manner to perform a related water hammer experiment of reservoir water supply; the water supply is provided for the closed-loop pipeline and the ground water tank through the water pump and is used for a pump-stopping water hammer and an upstream valve-closing transient flow experiment; when a water pipe is connected outside the closed loop pipeline, a water hammer experiment of a reservoir at the downstream is carried out, a three-way pipe is connected at the downstream of the closed loop pipeline, the solenoid valve seven is installed on the rest branch pipe on the three-way pipe, and the solenoid valve seven is used for connecting an exhaust valve.
The beneficial effects of the utility model reside in that:
1. the experiment table can be used for measuring the water hammer pressure wave velocity of the pipeline system with different pipe combinations under multiple experiment working conditions.
2. The experiment table can be correspondingly provided with a plurality of different experiment working conditions according to different experiment sites, and can basically meet the requirements of various experiment sites;
3. the experiment table is based on a computer for controlling each valve and collecting data, can remotely control and monitor a pipeline system, reduces the workload of workers and provides a working environment suitable for measuring and analyzing the water hammer wave velocity.
Drawings
FIG. 1 is a schematic structural view of the present invention;
wherein: 1. a water drainage tank; 2. a fifth electromagnetic valve; 3. a fourth electromagnetic valve; 4. a second pneumatic valve; 5. a second pressure sensor; 6. a first pressure sensor; 7. a first pneumatic valve; 8. a flow meter; 9. a ground water tank; 10. a sixth electromagnetic valve; 11. a water replenishing pipe; 12. a power distribution cabinet; 13. a third electromagnetic valve; 14. a seventh electromagnetic valve; 15. a first electromagnetic valve; 16. a computer; 17. a water pump; 18. a second electromagnetic valve; 19. a high-level water tank; 20. an overflow pipe; 21. a closed loop pipeline; 22. a water flow pipe; 23. a third pressure sensor; 24. replacing the tube; 25. and a third pneumatic valve.
Detailed Description
As shown in FIG. 1, the experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions comprises a ground water tank 9, a solenoid valve seven 14, a water pump 17, a high-level water tank 19, a closed-loop pipeline 21 and a water flowing pipe 22; the high-level water tank 19, the water pump 17 and the ground water tank 9 are all connected in series on a closed loop pipeline 21, at least one replacement pipe 24 is arranged in the closed loop pipeline 21 and is in pipeline loose joint with the closed loop pipeline 21 through two clamp type loose joints, and the high-level water tank 19 supplies water to the closed loop pipeline 21 and the ground water tank 9 in a stable pressure manner to perform a related water hammer experiment of reservoir water supply; the water is supplied to the closed-loop pipeline 21 and the ground water tank 9 through the water pump 17, wherein the water source of the water pump 17 is municipal water supply and is used for a pump-stopping water hammer and an upstream valve-closing transient flow experiment; when a water flowing pipe 22 is externally connected to the closed-loop pipeline 21, a downstream water hammer closing experiment is carried out, a three-way pipe is connected to the upstream of the closed-loop pipeline 21, the seven electromagnetic valves 14 are installed on the rest branch pipes on the three-way pipe, and the seven electromagnetic valves 14 are used for being communicated with exhaust valves.
The high-level water tank 19 is connected with two pipelines of the closed-loop pipeline 21, the first electromagnetic valve 15 and the third electromagnetic valve 13 are respectively arranged on the two pipelines, the water supply and the water cut-off of the high-level water tank 19 are realized by opening and closing the first electromagnetic valve 15 and the third electromagnetic valve 13, the second electromagnetic valve 18 is arranged on the pipeline, connected with the closed-loop pipeline 21, of the water pump 17, and the water supply and the water cut-off of the water pump 17 are realized by opening and closing the second electromagnetic valve 18.
At least two pressure sensors are mounted on the closed-loop pipeline 21.
The replacement pipe 24 can be replaced with a pipe of a different pipe material.
The water flowing out of the water flowing pipe 22 flows into the water draining groove 1, the air-operated valve three 25 is arranged on the water flowing pipe 22, and the closed loop pipeline 21 controls the water flow direction through the electromagnetic valve five 2 arranged on the closed loop pipeline and the electromagnetic valve four 3 arranged on the water flowing pipe 22.
An overflow pipe 20 is arranged at the upper end of the high-level water tank 19, and the overflow pipe 20 is connected to the ground water tank 9.
And a water replenishing pipe 11 provided with a six electromagnetic valve 10 is arranged on the ground water tank 9.
And a first pneumatic valve 7 and a second pneumatic valve 4 are respectively arranged at the upstream and the downstream of the closed-loop pipeline 21.
The closed loop pipeline 21 is provided with a flowmeter 8. The flowmeter 8 adopts an electromagnetic flowmeter, and the use of the electromagnetic flowmeter can not only reduce the impedance of the electromagnetic flowmeter to the pipe flow to the maximum extent, but also can accurately measure the flow of the pipe flow.
The first electromagnetic valve 15, the second electromagnetic valve 18, the third electromagnetic valve 13, the fourth electromagnetic valve 3, the fifth electromagnetic valve 2, the sixth electromagnetic valve 10, the seventh electromagnetic valve 14 and the at least two pressure sensors are controlled by a computer 16 and are powered by a power distribution cabinet 12.
The pressure sensor converts the pressure signal into an analog signal, and the analog signal is converted into a digital signal by the data acquisition unit and then sent to the computer 16 for calculation and analysis. The computer 16 can remotely control each valve by connecting a control chip; and converting signals such as flow and pressure acquired by the data acquisition unit into a visual data analysis chart.
The working method comprises the following steps: in the system shown in fig. 1, different hydraulic conditions are achieved by controlling three solenoid valves upstream of the pipe: the first control electromagnetic valve 15 and the third control electromagnetic valve 13 are closed, the second control electromagnetic valve 18 is opened to realize direct water supply of the water pump 17, and the water pump can be used for pump-stopping water hammer and upstream valve-closing transient flow experiments; and the first control electromagnetic valve 15 and the third control electromagnetic valve 13 are opened, and the second control electromagnetic valve 18 is closed, so that the pressure stabilization and water supply of the high-level water tank can be realized, and the related hydraulic transient experiment of reservoir water supply is carried out. In the figure 1, a fourth electromagnetic valve 3 at the downstream of the pipeline system is closed, and a fifth electromagnetic valve 2 is opened, so that a hydraulic transient experiment with a downstream tail end serving as a valve can be realized; and the fourth electromagnetic valve 3 is opened, and the fifth electromagnetic valve 2 is closed, so that the water hammer experiment of the downstream reservoir can be realized.
When the electromagnetic valve seven 14 is in an open state, the exhaust valve can be communicated to play a role of exhausting, and the gas content of the pipe flow of the closed-loop pipeline 21 is controlled to be lowest; when the exhaust valve is used, air and water vapor in the closed-loop pipeline 21 can be exhausted out of the pipeline system, so that pure liquid-phase hydraulic transient flow is generated,
the seven electromagnetic valve 14 can perform a gas-liquid two-phase transient flow experiment in a closed state. The ground water tank 9 can also be used as a downstream reservoir of a pipeline system besides the water storage function, and the water level of the ground water tank 9 is automatically or actively regulated and controlled by the computer 16 through the electromagnetic valve six 10. The pipeline to be tested is replaced between the two clamp type movable joints. Before the water hammer experiment related to valve closing is carried out, the corresponding valve is adjusted according to different working condition requirements and the operation, and the computer 16 is used for remotely controlling the pneumatic valve I7 (pneumatic valve II 4) to carry out the water hammer experiment of upstream valve closing (downstream valve closing).
And after the corresponding water hammer experiment is finished, analyzing and processing the acquired pressure and flow data. The experimental data are analyzed through a filtering method, and the water hammer pressure wave velocity of the corresponding pipe can be accurately obtained.
A pair of clamp type movable joints are arranged in a pipeline system of the experiment table, so that different mixed pipe forms can be realized in the same pipeline system. Pressure sensors are respectively arranged beside the two clamp-type movable joints (such as a pressure sensor I6 and a pressure sensor II 5 in the figure 1, and a pressure sensor III 23 is arranged on the closed-loop pipeline 21 on the other side) and can transmit pressure signals to the computer 16 in real time after transient flow occurs so that the computer 16 can calculate and analyze the wave speed of the water hammer pressure wave.
Firstly, test bed equipment and experiment process suggestion:
1. the pipes and the pipe fittings (overflow pipe 20, closed loop pipe 21, water flowing pipe 22, replacement pipe 24 and three-way pipe) of the experiment table are required to have the same inner diameter as much as possible, so that the flow resistance is reduced.
2. The water pump 17 should be a fixed-frequency water pump as much as possible, and if a variable-frequency water pump is necessary, the signal line of the water pump frequency converter should be prevented from contacting with the signal line of each sensor.
3. The sampling frequency of the acquisition card (the acquisition card is arranged near the computer 16 and is mainly used for acquiring pressure, flow and strain data and transmitting the acquired data to the computer 16) is more than 2 times of the fluctuation frequency of the water hammer pressure wave (for example, the sampling frequency of the acquisition card is about 2000Hz for a steel pipe, and about 500Hz for a plastic pipe).
4. The precision requirement of the pressure sensor is high (the precision is generally about +/-0.25%), and the cathodes of the signal lines of the sensors are uniformly and intensively grounded to prevent the interference of external signals.
5. The valves (the second pneumatic valve 4, the first pneumatic valve 7 and the third pneumatic valve 25) for transient flow excitation are preferably solenoid valves or pneumatic valves with high reaction speed, and the pneumatic solenoid valves are preferably spherical pneumatic solenoid valves with response time less than 0.2 s.
6. The water source used in the experiment should be pretreated by pressurization to remove air bubbles in the water. During the operation, the gas is not required to be entrained, so that a gas-liquid two-phase flow is formed. The exhaust valve is normally mounted directly above the closed loop pipe 21, vertically. The exhaust valve is directly connected to the highest point of the pipeline when in threaded connection.
7. The flow meter 8 should be selected as low resistance flow meter as possible (e.g. electromagnetic flow meter or ultrasonic flow meter).
8. Before the experiment, the water temperature in the pipe, the basic parameters of the pipe (such as the elastic modulus, the pipe diameter and the wall thickness of the pipe), and the initial flow and pressure of the pipe system under the steady-state working condition are measured.
9. Before the experiment, the constraint conditions of the pipeline system are determined, and the corresponding correction coefficients are determined through wave velocity empirical formulas in different pipeline system constraint forms.
II, principle and technical support suggestion:
(1) calculating the wave velocity of the water hammer by a theoretical formula
1. The known basic parameters of the pipe are as follows: inner diameter D, wall thickness E, and elastic modulus E, Poisson ratio upsilon.
2. And obtaining the water body temperature T by the thermometer, and then checking the density rho.
3. Using formulas
Solving the theoretical wave velocity of the water hammer, and determining a correction coefficient C according to the constraint conditions of different pipeline systems0Then the wave velocity formula becomes
Wherein the bulk modulus K of water is 2.1 × 109N/m2。
The influence of the pipe support type on the wave velocity can be divided into the following three cases:
a) the pipe is anchored only upstream and,
b) the pipe is fully anchored against axial movement, (C)0＝1-ν2)；
c) Anchored by telescopic joints (C)0＝1.0)；
(2) Experimental method for determining water hammer wave velocity
1. According to the pressure curve of the pressure sensor by
The velocity of the experimental water hammer wave, where t1、t2The time(s) for the pressure sensor to acquire the initial pressure rise (pressure drop) and L is the relative distance (m) between the two pressure sensors.
2. And comparing the water hammer wave velocity calculated through experimental data with a theoretical calculation value so as to determine the water hammer wave velocity of the pipeline system.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. 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 (9)
1. The utility model provides a different tubular product water hammer pressure ripples speed laboratory bench under measurable multiplex condition which characterized in that: comprises a ground water tank (9), an electromagnetic valve seven (14), a water pump (17), a high-level water tank (19), a closed-loop pipeline (21) and a water flowing pipe (22); the high-level water tank (19), the water pump (17) and the ground water tank (9) are all connected in series on a closed loop pipeline (21), at least one replacement pipe (24) is arranged in the closed loop pipeline (21) and is in pipeline loose joint with the closed loop pipeline (21) through two clamp type loose joints, and the high-level water tank (19) supplies water to the closed loop pipeline (21) and the ground water tank (9) in a stable pressure manner to perform a related water hammer experiment of reservoir water supply; a water pump (17) is used for supplying water for a closed-loop pipeline (21) and a ground water tank (9) and is used for a pump-stopping water hammer and upstream valve-closing transient flow experiment; when a water flowing pipe (22) is connected to the outside of the closed-loop pipeline (21), a downstream valve closing water hammer experiment is carried out, a three-way pipe is connected to the upstream of the closed-loop pipeline (21), a seven electromagnetic valve (14) is installed on the rest branch pipes on the three-way pipe, and the seven electromagnetic valve (14) is used for being connected with an exhaust valve.
2. The experiment table capable of measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 1, is characterized in that: the high-level water tank (19) is connected to two pipelines of the closed-loop pipeline (21) and is provided with a first electromagnetic valve (15) and a third electromagnetic valve (13) respectively, the high-level water tank (19) is supplied with water and stopped by opening and closing the first electromagnetic valve (15) and the third electromagnetic valve (13), the water pump (17) is connected to the pipeline of the closed-loop pipeline (21) and is provided with a second electromagnetic valve (18), and the water pump (17) is supplied with water and stopped by opening and closing the second electromagnetic valve (18).
3. The experiment table capable of measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 2, is characterized in that: at least two pressure sensors are arranged on the closed loop pipeline (21).
4. The experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 2 or 3, wherein the experiment table comprises: the water flowing out of the water flowing pipe (22) flows into the water drainage tank (1), a third pneumatic valve (25) is installed on the water flowing pipe (22), and the closed-loop pipeline (21) controls the water flow direction through a fifth electromagnetic valve (2) arranged on the closed-loop pipeline and a fourth electromagnetic valve (3) arranged on the water flowing pipe (22).
5. The experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 4 is characterized in that: an overflow pipe (20) is arranged at the upper end of the high-level water tank (19), and the overflow pipe (20) is connected to the ground water tank (9).
6. The experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 5, is characterized in that: and a water replenishing pipe (11) provided with a six electromagnetic valve (10) is arranged on the ground water tank (9).
7. The experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 6, is characterized in that: and a pneumatic valve I (7) and a pneumatic valve II (4) are respectively arranged at the upstream and the downstream of the closed loop pipeline (21).
8. The experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 7 is characterized in that: and a flowmeter (8) is arranged on the closed loop pipeline (21).
9. The experiment table for measuring the wave velocity of the water hammer pressure wave of different pipes under multiple working conditions according to claim 8 is characterized in that: the electromagnetic valve I (15), the electromagnetic valve II (18), the electromagnetic valve III (13), the electromagnetic valve IV (3), the electromagnetic valve V (2), the electromagnetic valve VI (10), the electromagnetic valve VII (14) and the at least two pressure sensors are all controlled by a computer (16) and are powered by a power distribution cabinet (12).
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113639987A (en) * | 2021-06-21 | 2021-11-12 | 广州市自来水有限公司 | Valve state detection system and method based on transient flow |
| CN114112454A (en) * | 2021-09-14 | 2022-03-01 | 中国人民解放军海军潜艇学院 | Water hammer comprehensive protection method for ship water transfer system |
-
2020
- 2020-10-30 CN CN202022483228.4U patent/CN213022232U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113639987A (en) * | 2021-06-21 | 2021-11-12 | 广州市自来水有限公司 | Valve state detection system and method based on transient flow |
| CN114112454A (en) * | 2021-09-14 | 2022-03-01 | 中国人民解放军海军潜艇学院 | Water hammer comprehensive protection method for ship water transfer system |
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