A low-intensity transient current exciter

Abstract

The invention discloses a low-intensity transient flow exciter. The low-intensity transient flow exciter comprises an energy accumulator air tank used for storing compressed air and water, a magnetostriction liquidometer arranged on the energy accumulator air tank and used for measuring the water level falling amplitude and speed in the energy accumulator air tank in real time, and a pressure meter arranged on the top of the energy accumulator air tank and used for measuring the pressure value of air of the energy accumulator air tank in real time. One end of a water outlet pipe is connected with the bottom of the energy accumulator air tank, the other end of the water outlet pipe is connected with a pipeline at the tail end of a pipe net system through a control ball valve, high-pressure water is provided for the pipe net system through rapid opening or closing of the control ball valve, and low-intensity transient flow is generated. The low-intensity transient flow exciter is simple in structure, economical and practical, influences on the pipeline from the flow change generated due to excitation are weak, and the water attack pressure waves of the pipeline system can be calculated only by measuring four key parameters; and the low-intensity transient flow exciter is not sensitive to the control ball valve opening speed, ball valve opening and closing control is convenient, and operability of the leakage transient detection method in the actual pipeline project is greatly improved.

Description

technical field [0001] The invention relates to leak detection equipment for water supply pipelines and pipe network systems, in particular to a low-intensity transient flow exciter. Background technique [0002] The transient detection method is a method with high accuracy and reliability in the leakage detection of water supply pipelines and pipe networks, because under transient conditions, even if there is a small leakage, the water pressure waveform of the pipeline is obviously different, which is different from other Compared with other methods (such as pressure gradient method, negative pressure wave method, etc.), using this feature can better determine the location of leakage. [0003] In the field of water diversion or water supply engineering, the generalized physical models of pipeline systems currently studied internationally are as follows: figure 1 As shown, the leakage detection method of this arrangement type is specifically as follows: the end excitation v...

AI Technical Summary

Problems solved by technology

For modern large-scale pipeline water diversion projects, the line is long and the diameter of the pipeline is large. In order to reduce pipeline investment, slow valve opening and closing speeds are generally used to reduce the water hammer pressure on the pipeline, or to prevent the pipeline from vaporizing due to low instantaneous pressure. In order to ensure the safe operation of the system; for the pipe network water supply system, due to the different pressure resistance of various pipe materials (such as steel pipes, PE pipes, cast iron pipes, cement pipes, etc.), the pressure of the rapid closing of the valve is too large to easily cause water hammer problems , it may increase the risk of tube explosion, so this transient flow excitation method is not feasible

[0010] (2) Use the small opening of the valve at the end of the pipeline to quickly fully close or fully open to generate flow pulses, which are not easy to control during operation

Although the flow rate of the pipeline decreases after the valve opening is reduced, and the transient flow pressure induced by the rapid full opening or full closing of the valve is much lower than that of the large opening, it will not have a major impact on the safety of the pipeline, but the small opening of the valve The degree flow coefficient is not easy to determine, and it is necessary to determine the valve closing law, that is, the relationship between the valve opening degree and the flow coefficient

[0011] (3) When the pipeline valve is completely closed, the change process of the valve flow rate has no effect on the hydraulic transient in the pipeline and is uncertain, which may cause errors in the final detection results

When the time T of the pipeline valve is completely closed is very short, such as T≤L / a (L is the pipe length, a is the water hammer wave velocity), the change of the valve flow rate can be expressed by the pulse function, because the shape of the valve flow change process curve has a great influence on the pipeline The medium hydraulic transient has no effect; however, when the valve is closed slowly (manual fast closing generally takes about 0.2 seconds), the curve shape of the valve flow change process has a great influence on the hydraulic transient in the pipeline, which cannot be used The pulse function describes the change of the valve flow, that is, it cannot be simply expressed by a flow pulse function. In this case, the flow change process has a great influence on the hydraulic transient, and it must be considered

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