JP2891480B2 - Level measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention reduces water injection time in a level measuring device that monitors long-term level fluctuations such as measurement of uneven settlement of a structure using a plurality of manometers. About the means.

(Prior art) As a monitoring device for level fluctuation over a long period of time, such as measurement of uneven settlement of a structure, a reference manometer that continuously detects a water surface level and a number of displacement manometers that detect a predetermined water surface level are provided. A device that communicates with each other through a channel and continuously injects water into this pipeline to measure the level at each point where a displacement manometer is arranged has been proposed with the present applicant as a joint applicant (Japanese Patent Application Laid-Open (JP-A) no. No. 63-269235).

In such a level measuring device, if water is left in the manometer or the pipe for a long period of time, undesirable phenomena such as mold generation and water decay are likely to occur, and therefore the measurement is performed. After that, it is desirable to empty the manometer and the pipe line and to inject fresh water every time of measurement.

(Problems of the Invention) In such a case, if a large amount of water is injected in a short time, frictional loss increases in the pipeline, so that a water level difference that cannot be ignored between the manometer near the water injection position and the manometer far from the water injection position. This causes a problem that measurement accuracy is deteriorated. On the other hand, if the water injection is performed little by little, such a problem does not occur, but instead, the time from the start of the water injection to the completion of the level measurement becomes longer.

The present invention has been made to solve the above problems, and an object of the present invention is to reduce the time required for measurement without lowering the measurement accuracy.

(Means for Achieving the Object) According to the present invention, a reference manometer that continuously detects a water surface level and a displacement manometer that detects a predetermined water surface level and are disposed at each measurement point are interconnected via a pipeline. In a level measuring device that sequentially detects the height of each measurement point by continuously injecting water into this pipe, a water injection valve A that performs high-speed water injection and a low-speed water injection are provided between the pipe and the water source. And a means for opening the water injection valve A when the water level of the reference manometer falls below a predetermined level, and closing the water injection valve A when the water level exceeds the predetermined level.

(Function) By high-speed water injection through the water injection valve A, a large amount of water is injected in a short time until the water level of the reference manometer reaches a predetermined level, and when the water level exceeds the predetermined level, the high-speed water injection valve A closes. By pouring little by little from low-speed water injection valve B,
Minimize differential friction loss in the pipeline. Since the level measurement is started at this stage, the water injection time is reduced without impairing the measurement accuracy.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a reference manometer, and reference numeral 2 denotes a displacement manometer which communicates with the reference manometer 1 through a pipe 3.

The reference manometer 1 includes a float that rises and falls with the water level therein, and outputs a water level signal corresponding to the rise and fall of the float to the controller 4.

In addition, the displacement manometer 2 includes a sensor that detects that the water level has reached a specific level. This sensor is composed of an electrode in contact with the rising water surface and a signal circuit formed by using the water as a conductive path. When the water surface contacts the electrode, a current flows through the signal circuit. This signal circuit is connected to the controller 4 together with the signal circuit from the reference manometer 1.

A high-speed water injection valve A and a low-speed water injection valve B are interposed between the pipe 3 and the water source 5 in parallel. The high-speed water injection valve A includes a fixed throttle 6 and a solenoid valve 7 arranged in series, and the low-speed water injection valve B includes a fixed throttle 8 and a solenoid valve 9 arranged in series. The fixed throttle 6 has a larger flow cross-sectional area than the fixed throttle 8.
Reference numeral 12 denotes a filter for filtering water supply.

An electromagnetic valve 10 is interposed between the pipe 3 and the drain 11 for draining the reference manometer 1, the displacement manometer 2 and the pipe 3.

These solenoid valves 7, 9 and 10 are respectively connected to the controller 4 by a signal circuit, and open and close according to an open / close signal output from the controller 4 to the signal circuit.

The controller 4 closes the solenoid valve 10 and opens the solenoid valve 7 in response to the water injection start signal input by the operator. Also,
When the water level signal input from the reference manometer 1 reaches a predetermined value, the solenoid valve 7 is closed and the solenoid valve 9 is opened. This set value is set to a level lower than the specific water level detected by the displacement manometer 2.

Further, when the input signal from the displacement manometer 2 changes to ON, the controller 4 displays the level of the measurement point where the displacement manometer 2 is installed based on the water level signal input from the reference manometer 1 at that time.

Further, the controller 4 controls all the displacement manometers 2.
When the output signal of the switch turns ON, the solenoid valve 9 is closed and the solenoid valve 10 is closed.
open.

 Next, the operation will be described.

When no measurement is performed, the solenoid valve 10 is opened, and the reference manometer 1, the displacement manometer 2, and the pipe 3 are all kept empty. When performing the level measurement, the operator inputs a water injection start signal to the controller 4, and the controller 4 closes the solenoid valve 10 and opens the solenoid valve 7 accordingly,
High-speed water is injected into the pipe 3 from a water source 5 through a fixed throttle 6 having a large cross-sectional area.

The water level of the reference manometer 1 and the displacement manometer 2 rises rapidly with water injection. The controller 4 compares the water level signal input from the reference manometer 1 with a predetermined value set in advance, and continues this rapid water injection as long as the water level signal falls below the set value as shown in FIG.

Then, when the water level signal reaches the set value, the controller 4 closes the solenoid valve 7 and opens the solenoid valve 9. Thereafter, the water is injected into the pipe 3 little by little through the fixed throttle 8 having a small flow cross-sectional area, and the rising speed of the water level of the reference manometer 1 and each displacement manometer 2 decreases. The decrease in the flow rate reduces the friction loss of the pipe 3 and the difference in water level between the reference manometer 1 and each displacement manometer 2 due to the friction loss is eliminated.

In this way, when the low-speed water injection proceeds, the output signal of the displacement manometer 2 installed at the lowest position eventually changes to ON,
The controller 4 displays the level of the measurement point where the displacement manometer 2 is installed based on the water level signal input from the reference manometer 1 at that time.

When the low-speed water injection is further continued, the output signals of the other displacement manometers 2 are turned on one after another, and the controller 4 determines the level of the measurement point where each displacement manometer 2 is installed based on the water level signal input from the reference manometer 1 each time. Is displayed. Since the water injection is performed at a low speed, the measured level has sufficient accuracy.

When the output signals of all the displacement manometers 12 change to ON, the controller 4 determines that the measurement has been completed, closes the solenoid valve 9 and opens the solenoid valve 10. As a result, while the water injection is stopped, the water in the pipe 3, the reference manometer 1 and each displacement manometer 2 is drained through the drain 11.

In this way, the level measurement can be completed in a short time after the start of water injection.

(Effect of the Invention) As described above, according to the present invention, the water injection valve A for performing high-speed water injection and the water injection valve B for performing low-speed water injection are interposed in parallel between the pipeline and the water source, and the water level of the reference manometer is predetermined. When the water level falls below the predetermined level, the water injection valve A is opened. When the water level exceeds a predetermined level, the water injection valve A is closed. Thereby, the friction loss of the pipeline can be reduced.

Therefore, the speed of the measurement operation can be increased without reducing the measurement accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a level measuring device showing an embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of the controller. 1 ... Reference manometer, 2 ... Displacement manometer, 3 ...
Pipe line, 4 ... Controller, 5 ... Water source, 6,8 ... Fixed throttle, 7,9,10 ... Solenoid valve, A ... High speed water injection valve, B ... Low speed water injection valve.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-61-95209 (JP, A) JP-A-2-115712 (JP, A) JP-A-2-243915 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G01C 5/04 G01C 9/18-9/22

Claims (1)

(57) [Claims] 1. A reference manometer for continuously detecting a water surface level and a displacement manometer for detecting a predetermined water surface level and disposed at each measurement point are connected to each other through a pipe, and are connected to this pipe. In a level measuring device that sequentially detects the height of each measurement point by continuously injecting water, a water injection valve A for performing high-speed water injection and a water injection valve B for performing low-speed water injection are arranged in parallel between a pipeline and a water source. And a means for opening the water injection valve A when the water level of the reference manometer falls below a predetermined level, and closing the water injection valve A when the water level exceeds the predetermined level.