JP2001174361A - Hydraulic pressure test device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine quality of water-tightness on the basis of the hydraulic pressure lowering characteristic in a synthetic resin-made pipeline. SOLUTION: Initial hydraulic pressure is applied inside of a synthetic resin- made pipeline and a change with the lapse of time is detected by a hydraulic pressure detecting means. The hydraulic pressure and the passing time detected in order are respectively converted to logarithmic values by a logarithm converting means. Change of the hydraulic pressure value converted to the logarithm in relation to the passing time converted to the logarithm is outputted as the hydraulic pressure lowering characteristic. For example, the hydraulic pressure lowering characteristic is computed as a first and a second approximate straight line, and a slope ratio of the first approximate straight line to the second approximate straight line is computed. In the case where the slope ratio is a certain value or more, water-tightness of the pipeline is determined satisfactory, and in the case where the slope ratio is less than the certain value, probability of water leak is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic test apparatus,
More particularly, the present invention relates to a hydraulic test apparatus for judging the watertightness of a pipe made of synthetic resin buried underground, for example.

[0002]

2. Description of the Related Art When a hydraulic test is performed on a synthetic resin pipe such as a polyethylene pipe, the pipe expands due to the initial water pressure applied to the pipe because the pipe has flexibility.
The water pressure drops as shown in FIG. Therefore, when a hydraulic test of a synthetic resin pipeline is performed using a conventional hydraulic test device corresponding to a hard pipeline such as a ductile cast iron pipeline, is such a water pressure drop caused by water leakage? Or, it was difficult to determine whether the cause was expansion of the tube.

On the other hand, a research report on the water pressure drop characteristics of a synthetic resin pipe has been reported in the WRC (Water Research Center) in the UK.
r). According to this, when the relationship between the elapsed time and the water pressure change is plotted on a log-log graph, the water pressure drop characteristic graph is as shown in FIG. That is, when there is no water leakage in the pipeline and the water tightness is maintained, a straight line A descends to the right, and when there is water leakage in the pipeline and the water tightness is impaired, the curve B is located below the straight line A, When air is mixed in the pipeline,
The curve C is located above the straight line A.

Accordingly, a hydraulic pressure test apparatus for a synthetic resin pipe based on the hydraulic pressure drop characteristic has been developed, and an example thereof is disclosed in Japanese Patent Application Laid-Open No. 11-166871.

[0005]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. H11-1668
In the hydraulic pressure test apparatus disclosed in Japanese Patent Publication No. 71, an approximate curve is calculated by graphing the relationship between the elapsed time and the change in hydraulic pressure, and an approximate curve is calculated. Is determined.

However, it is difficult to eliminate suddenly erroneously detected data due to a detection error of the water pressure test device or a disturbance factor. Even if a dead zone is provided as a criterion, erroneous determination of watertightness may be caused. There was sex.

[0007] Therefore, a main object of the present invention is to provide a water pressure test apparatus capable of accurately determining the quality of water tightness based on the water pressure drop characteristics of a synthetic resin pipeline.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a water pressure test apparatus for judging whether watertightness is good or bad based on a change over time of water pressure applied to a synthetic resin pipe. Water pressure detection means for detecting, and logarithmic conversion means for respectively converting the water pressure value sequentially detected by the water pressure detection means and the elapsed time from the time when the initial water pressure was applied to logarithmic values,
Whether the watertightness of the pipeline is good or bad is determined based on the gradient ratio between the first approximate straight line and the second approximate straight line that is expressed when the relationship between the water pressure value log-converted by the logarithmic conversion means and the elapsed time is graphed. It is a hydraulic test device to be determined.

[0009]

A hydraulic pressure is applied to a pipe made of a synthetic resin, and a change with time is detected by a hydraulic pressure detecting means. The sequentially detected water pressure value and elapsed time are respectively converted into logarithmic values by logarithmic conversion means. Then, a change in the logarithmically converted hydraulic pressure value with respect to the logarithmically converted elapsed time is output as a hydraulic pressure drop characteristic.

The present inventor has proposed a water pressure test apparatus (Japanese Patent Laid-Open No. 11-1).
As a result of continuing verification with respect to Japanese Patent Application Laid-Open No. 66871, when a graph of the water pressure drop characteristic when there is water leakage in the pipeline is provided, as shown in FIG. 1) and draws an inflection point at a certain point in time, and then draws an approximate straight line (second approximate straight line) with a relatively large slope toward the right, and also draws the first approximate straight line and the second approximate straight line. It was verified that the quality of the watertightness can be determined based on the gradient ratio with the approximation line of 2.

Therefore, according to the present invention, the hydraulic pressure drop characteristic is the first.
And a second approximate straight line, and a gradient ratio between the first approximate straight line and the second approximate straight line is calculated. The slope ratio is
When there is no water leakage in the pipeline, the value is close to 1, and when the amount of water leakage in the pipeline is large, the value is close to 0. Therefore, when the gradient ratio is a certain value or more, it is determined that the watertightness of the pipeline is good, otherwise,
It is determined that there is a possibility of water leakage or that retesting is necessary due to insufficient test conditions.

[0012]

According to the present invention, the quality of water tightness is accurately determined based on the gradient ratio between the first approximate straight line and the second approximate straight line in the hydraulic pressure drop characteristic of a synthetic resin pipeline. be able to.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a hydraulic pressure test apparatus 10 of this embodiment is used for a hydraulic pressure test for a synthetic resin pipe such as a polyethylene pipe buried in the ground. To determine the quality of the watertightness of the pipeline.

The hydraulic pressure test apparatus 10 includes a pressure sensor 12 for detecting a water pressure in a pipeline, and a device main body 14 for displaying a hydraulic pressure drop characteristic in a graph and judging whether or not the watertightness of the pipeline is good and informing.

The pressure sensor 12 is set in a pipe made of a synthetic resin to be tested and detects the water pressure in the pipe. For example, a well-known type such as a Bourdon pipe type, a bellows type, and a diaphragm type is used. Pressure sensor is used.

The apparatus main body 14 includes a casing 14a, and a control unit 16 is provided inside the casing 14a.

As shown in FIG. 2, the control unit 16 temporarily stores a CPU 18 for performing a predetermined calculation or control process, a ROM 20 in which a predetermined processing program (including a judgment on the quality of test results) is stored, and data. RAM2 to be stored in
2, and the entire operation is controlled according to the above-mentioned predetermined program.

The CPU 18 has a pressure sensor 1 via an A / D converter 24 for converting an analog signal into a digital signal.
2 is connected, and the operation keys 26, the display unit 28,
The printer 30 and the notification unit 32 are connected.

The operation keys 26 are provided on the upper surface of the casing 14a, for example, as shown in FIG. 1, and include a key group such as a test time setting key, a test start key, a test end key, a print instruction key, an ambient temperature, and a pipeline. And a key group for inputting a correction element that affects the hydraulic pressure drop characteristics such as the branch structure of the pipe and the height difference of the pipeline. When the operation key 26 is operated, a signal corresponding to each operation is output to the CPU 18.

The display unit 28 is an LCD (Liquid Crystal D)
isplay) or the like, and is provided, for example, on the upper surface of the casing 14a. The display unit 28 receives the signal output from the CPU 18 and graphically displays the water pressure drop characteristic of the synthetic resin pipe.

The printer 30 receives the signal output from the CPU 18 and records the hydraulic pressure drop characteristic graph displayed on the display unit 28 on a chart paper or the like.

The notifying unit 32 includes an LED (Light Emitting D)
iode), etc., and when it is determined that the watertightness of the pipeline is good, a blue LED or the like is turned on to determine that the watertightness of the pipeline is poor or that a retest is necessary. When the test is performed, a red LED or the like is turned on to notify the test result (good or bad of watertightness of the pipeline).

The apparatus body 14 is operable with a battery.

Next, a method of performing a water pressure test on a synthetic resin pipe using the water pressure test apparatus 10 will be described.

First, a sealing jig such as a water stop flange and a cap is attached to an end of a synthetic resin pipe to be tested to seal the pipe, and a pressure sensor 12 is provided in the pipe.
Is set. Then, water is supplied into the pipeline by the water supply pump, and a predetermined initial water pressure is obtained in the pipeline. This initial water pressure value needs to be set to a suitable value according to the purpose of the pipe, the structure of the pipe, the type of pipe such as wall thickness and diameter, and the like.

On the other hand, the power switch of the apparatus main body 14 is turned on.
The operating keys 26 are used to set the conditions required for the test such as the correction factors such as the ambient temperature, the branch structure of the pipeline, the height difference of the pipeline, and the test time.
To enter.

When a state where a predetermined initial water pressure is applied to the pipeline is obtained, the test is started by turning on the test start key of the operation key 26.

Hereinafter, the control operation of the CPU 18 of this embodiment will be described with reference to the flowchart of FIG. The elapsed time from when the test start key is turned on, that is, when the initial hydraulic pressure is applied to the pipeline is measured by a timer in the CPU 18.

In step S1, a process of taking in a water pressure value is performed. This process is performed based on a preset water pressure value taking interval. Here, the intake interval of the water pressure value is set in advance corresponding to the test time input by the test time setting key of the operation key 26. That is, since the synthetic resin pipe expands due to the applied initial water pressure, the rate of change with time (water pressure drop) of the water pressure value is relatively large immediately after the start of the test. Therefore, in this time zone, the data capture interval is set to be short, such as at intervals of 1 second, 5 seconds, 10 seconds, etc., so that the behavior of the water pressure value over time can be finely captured. On the other hand, after a certain period of time has elapsed since the start of the test, the rate of change over time (water pressure drop) of the water pressure value becomes relatively small. Therefore, in this time zone, the data acquisition interval is set long, for example, every 30 minutes.

In step S3, a process of logarithmically converting the water pressure value and the elapsed time is performed. In other words, for example, with water pressure value p _n, the time that captures and it is assumed to be t _n,
First, the hydraulic pressure value _pn is corrected with a correction value (or correction coefficient) set from correction elements such as the ambient temperature, the branch structure of the pipeline, and the height difference of the pipeline, and then the corrected hydraulic pressure value _pn ' Is logarithmically transformed with the acquisition time t _n . These values are R
It is written to AM22.

In step S5, the previous fetched data and the current fetched data are linearly approximated, and the gradient of the straight line is calculated. That is, for example, the previous data (water pressure value) is p _(n-1) , and the time when it was taken is t _(n-1)
, And the current data (pressure value) at p _n, the time that captures and it is assumed to be t _n, the ratio i.e. the approximate straight line from the log-transformed previous and current data, pressure change with respect to the elapsed time slope of Δ _(n-1) is calculated, which is written to the RAM 22. This gradient Δ _(n−1) is calculated based on Equation 1. In the first process immediately after the start of the test, the gradient calculation process is not performed because there is no previous data.

[0033]

[Number 1] _{Δ (n-1) = (} logp (n-1) '-logp n')
/ (Logt _n -logt _(n-1) ) Further, the measurement data is displayed on the display unit 28 at any time as a water pressure drop characteristic graph plotted on a square graph or a log-log graph. The display format of the graph can be selected by the graph display key of the operation key 26.

In step S7, it is determined whether the test has been completed. If the test time entered with the operation keys 26 has elapsed, or if the test end key of the operation keys 26 has been pressed, it is determined that the test has been completed; otherwise, it is determined that the test is ongoing. You. Step S7
If “YES” is determined in step S9, the process proceeds to step S9.
If "NO", the process returns to step S1 and the measurement is continued.

In step S9, an inflection point calculation process is performed. This processing is performed based on the water pressure drop characteristic when water leakage occurs in the pipeline. That is, as shown in FIG. 5, an inflection point occurs in the hydraulic pressure drop characteristic graph when water leakage occurs in the pipeline, and before and after this inflection point, the ratio of the temporal change of the water pressure value, that is, the approximate straight line It has the feature that the gradients differ greatly. Therefore, in order to calculate the inflection point, it is sufficient to detect a point having a greatly different gradient before and after a certain measurement point. Specifically, first gradient delta ₀ immediately after start of the test calculated in step S5 and the next slope delta ₁
Are read from the RAM 22 and compared with each other. Is approximately the value of the slope delta ₀ and delta ₁ same case (the ratio is close to 1), the points on the graph in the measurement time t ₁ is determined not to be the inflection point, the average slope delta ₀ and delta ₁ The value a ₀ is calculated. Subsequently, it is compared in the same manner for a ₀ and the next slope delta _2, if the values are about the same mean value a ₁ of them is calculated. In this way, the average value of the slope up to a certain measurement time t _k a _(k-2) and its subsequent slope Δ
_k are sequentially compared. And, if these values are significantly different, in terms of measurement time t _k it is determined to be the inflection point. On the other hand, if the values do not greatly differ, it is determined that there is no inflection point.

In step S11, it is determined whether or not there is an inflection point. If “YES” in the step S11, the process proceeds to the step S13. If “NO”, the process proceeds to the step S13.
Proceed to 15.

In step S13 (processing when there is an inflection point), the processing of calculating the gradient L1 of the first approximate straight line, the gradient L2 of the second approximate straight line, and the ratio R (= L1 / L2) of the gradients is performed. Done. Here, for example, the gradient L1 of the first approximate straight line is obtained by linearly approximating a point (measurement time t ₀ , water pressure p ₀ ) immediately after the start of the test and the inflection point,
The slope L2 of the approximation straight line is obtained by linearly approximating the inflection point and the end point of the test (measurement time t _n , water pressure _pn ).
The measurement time at the inflection point t _k, and the water pressure value and p _k,
The gradient L1 is calculated by Expression 2, and the gradient L2 is calculated by Expression 3.

[0038]

L1 = (logp ₀ '-logp _k ') / (lo
gt _k -logt ₀ )

[0039]

[Number 3] _{L2 = (logp k '-logp} n') / (lo
gt _n -logt _k ) Even in step S15 (processing when there is no inflection point), the first
Of the approximate straight line L3, the gradient L4 of the second approximate straight line, and the ratio R (= L3 / L4) of the gradients. However, since there is no inflection point here, for convenience, the first
Is an approximate straight line for m pieces of measurement data from the point immediately after the start of the test, and a second approximate straight line is an approximate straight line for m pieces of measurement data from the test end point. . Therefore, for example, the gradient L3 of the first approximate straight line is calculated by calculating the average value of the gradients Δ ₀ , Δ ₁ ,..., Δm for _m straight lines from the point immediately after the start of the test, In addition, the gradient L4 of the second approximate straight line is obtained by calculating m straight lines retroactively from the test end point.
It is calculated by calculating the average of the gradients Δ _(n-1) , Δ _(n-2) ,..., Δ _(nm) . The number of straight lines m
Is set based on the test time and data capture interval (measurement time) input by the operation keys 26, and the like.

The calculated first and second approximate straight lines are displayed on the display unit 28 together with the hydraulic pressure drop characteristic graph displayed on the display unit 28 at any time during the test, or independently. The display content of the display unit 28 can be output by a printer 30 on chart paper or the like.

Note that the above-described calculation of the gradient of the approximate straight line is as follows.
For example, the calculation may be performed by calculating an approximate linear function according to a function approximation method such as a least square method.

In step S17, it is determined whether or not the ratio R between the gradient of the first approximate straight line and the gradient of the second approximate straight line is equal to or greater than a predetermined value α. “YES” in step S17
If so, the process proceeds to step S19, and if “NO”, the process proceeds to step S21. Here, the predetermined value α is a reference value for determining whether the watertightness of the pipeline is good or not.
Is set to about 0.3 to 0.4, the quality of the watertightness of the pipeline can be almost surely determined. The value of α is determined by the local government or the like that manages the pipeline based on the research, experience, results, etc., so far.
Is entered.

In step S19, the notification unit 32
In step S21, the result of the determination that the watertightness is good is reported, for example, the blue LED is lit, and in step S21, the red LED is lit in the reporting unit 32, and the possibility of water leakage is increased. A determination is made that there is or that a retest is necessary.

In this way, the hydraulic test apparatus 10 performs a hydraulic test on the synthetic resin pipe to determine whether the watertightness is good or not.

According to this embodiment, the hydraulic pressure drop characteristic of the synthetic resin pipe is approximated to two straight lines, and the ratio of the gradient between the first and second approximate lines is calculated. Since the presence or absence of water leakage is determined based on the gradient ratio, the quality of water tightness can be accurately determined.

Since the quality of the water tightness is automatically determined and notified by the notification unit 32, and the water pressure drop characteristic graph is displayed on the display unit 28, accurate and comprehensive determination can be made.

In this example, after the test, the first
The gradient ratio between the approximate straight line and the second approximate straight line is automatically calculated to determine the quality of the water tightness. However, the water pressure drop characteristic graph (including the approximate straight line) displayed on the display unit 28 is used. ) Can be visually determined by the operator.

In addition, the result of the determination of the watertightness is reported by turning on the LED or the like in the reporting unit 32, but may be reported by an acoustic means such as a buzzer, or both. The notification may be made by using the means described above.

The determination result of the watertightness may be displayed on the display unit 28 as character information or the like. In this case, the notification unit 32 and the like do not need to be provided,
4 can be downsized.

Further, the hydraulic pressure drop characteristic, the determination result, and the like may be transmitted to a test management base or the like via a communication line or the like. In this case, since the printer 30 and the like need not be provided, the structure of the apparatus main body 14 can be downsized.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an embodiment of the present invention.

FIG. 2 is a control block diagram of the embodiment in FIG. 1;

FIG. 3 is a flowchart showing the operation of the embodiment in FIG. 1;

FIG. 4 is a hydraulic pressure drop characteristic graph (logarithmic graph) showing the relationship between the hydraulic pressure of the synthetic resin pipe and the elapsed time.

FIG. 5 is a water pressure drop characteristic graph (bilogarithmic graph) showing the relationship between the water pressure of the synthetic resin pipe and the elapsed time when there is water leakage in first and second approximate straight lines.

FIG. 6 is a hydraulic pressure drop characteristic graph (square graph) showing the relationship between the hydraulic pressure of the synthetic resin pipe and the elapsed time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Hydraulic test apparatus 12 ... Pressure sensor 14 ... Device main body 16 ... Control part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akiya Shibuya 2-35 Jinmucho, Yao-shi, Osaka F-term (Reference) 2F055 AA11 BB20 CC01 DD20 EE40 FF25 FF49 GG45 GG49 2G067 AA12 BB11 DD02 EE01

Claims (1)

[Claims] 1. A hydraulic pressure test apparatus for judging whether water tightness is good or bad based on a change over time of a hydraulic pressure applied to a synthetic resin pipe, a hydraulic pressure detecting means for detecting a water pressure in the pipe, And logarithmic conversion means for respectively converting the water pressure value sequentially detected by the water pressure detection means and the elapsed time from the time when the initial water pressure was applied to logarithmic values, and the water pressure value logarithmically converted by the logarithmic conversion means and The first that appears when the relationship with the elapsed time is graphed
A hydraulic test apparatus for determining whether the watertightness of the pipeline is good or not based on a gradient ratio between the approximate straight line and the second approximate straight line.