JPH1078345A - Level switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect the change of water level without being influence by an inflow matter such as refuse by floating a bag in which an electrode fixed to a level detecting position, a conductive liquid and air are sealed on the water surface to be level detected. SOLUTION: A pair of electrodes 3, 3 fixed near a level detecting position, a conductive liquid 5 and air 6 are sealed in the sealed soft bag 2 of this level detector 1, and the bag 2 is floated on the water surface to be level detected. When the level WL is lower than the bag 2, the liquid 5 is stayed in a position lower than the electrodes 3, 3, and when the level WL rises and reaches the level of the electrodes 3, 3, the lower part of the bag 2 is pushed by hydraulic pressure, the level of the liquid 5 is also raised to dip the electrodes 3, 3, and the electrodes 3, 3 are laid in continued state. This electrical state is taken as signal to the outside by cables 4, 4. Thus, the water level is converted into an electric signal and taken out in this way, whereby it can be precisely detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level detector which is installed in a landing well, a pump well, or the like when supplying or draining water using a pump, and is suitable for detecting the water level.

[0002]

2. Description of the Related Art For example, in a pump well or a landing well,
In order to automatically supply or drain water using a pump, it is widely practiced to automatically operate the pump while detecting one or both water levels with a water level detector.

Conventionally, as the water level detector, an electrode type,
What adopts a float type, a friction type, or the like is generally known. However, when dealing with sewage, sewage or rainwater, dirt, dirt, driftwood, etc., flow into the pump well or landing well. In the above-mentioned conventional water level detector, these inflows are easily caught by the water level detector, and the inflows easily make the water level detector inoperable. For example, filth adhered to the movable part of the water level detector, and became hard over time, and the water level detector became inoperable.

That is, in a water level detector employing an electrode type,
Insufficient conduction due to the adhesion of sewage, filth, etc., and erroneous operation due to contact with the inflow are likely to occur. In addition, in a water level detector employing a float type, accurate detection of the water level is hindered by the adhesion of the inflow. Furthermore, even in the case of a friction type level switch, the switch itself changes the position from vertical to horizontal or from horizontal to vertical due to a change in water level, and the built-in switch is activated, but the friction itself is caused by inflow or lead cable. At present, it is not possible to change the water level accurately due to the entanglement of the switch and to transmit the change in the water level to the switch.

[0005]

For example, in a drainage pump station for countermeasures against heavy rain in lowlands, if the water level rise cannot be detected quickly during heavy rain due to malfunction of the water level detector, the lowlands may be flooded. There is a strong demand for the development of a highly reliable water level detector to prevent the pump from running idle and the overflow of the landing well.

The present invention has been made in view of the above-mentioned circumstances, and is not affected by garbage, filth, or inflow of driftwood or the like even when handling sewage, sewage, rainwater, or the like. An object of the present invention is to provide a water level detector capable of accurately detecting a change in water level.

[0007]

The water level detector of the present invention comprises:
A pair of electrodes fixed in the vicinity of the water level detection position and a conductive liquid and air are sealed inside a sealed soft bag, and the bag floats on the surface of the water level to be detected, and the water surface rises. When the liquid surface of the conductive liquid rises to the height of the pair of electrodes, the electrodes are electrically connected to each other to detect a water level.

According to the present invention having the above-described structure, the level of the conductive liquid which is sealed in a soft bag and floats on the surface of the water rises as the surface of the water to be detected rises, and the conductive liquid becomes a pair of conductive liquids. When reaching the electrodes, the pair of electrodes conduct with each other. Then, by converting this conductive state into an electric signal and extracting it, the water level can be accurately detected. In particular, since the pair of electrodes and the conductive liquid that conducts the pair are sealed in a soft bag and float on the water surface, there is no problem that the inflow is caught between the electrodes. As a result, the water level can be detected with high reliability even in sewage with a large amount of inflow.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a water level detector.
As shown in FIG. 1, the water level detector 1 is provided with a closed bag 2, and a pair of electrodes 3, 3 is provided on the inner wall of the bag 2.
3 are arranged at the same height level and at a predetermined distance, and a lead wire cable 4 for taking out the outside is connected to each electrode 3 to a control device (not shown) outside the bag.

Here, the fixing portion 2a of the bag body 2 is a cylindrical fixing member made of, for example, acrylic, glass or vinyl chloride. A thin and soft film 2b such as rubber or vinyl is connected to the lower end of the fixed object 2a. or,
For pressure absorption attached to the upper end opening of the fixed object 2a,
For example, a thin and soft rubber film 2c is connected.

The bag 2 is filled with, for example, a conductive liquid 5 obtained by adding a salt to water and air 6. As described above, by adding a salt to water, a conductive liquid 5 having a density almost equal to that of water and having good conductivity can be obtained, but it is a matter of course that the present invention is not limited to this.

Here, in the normal state before installation as shown in FIG. 1, the conductive liquid 5 accumulates in the thin and soft bag portion 2b at the lower portion due to gravity, and air accumulates in the electrodes 3 and 3. The pair of electrodes 3 and 3 arranged on the inner wall surface of the bag body 2 are located above the liquid level of the conductive liquid 5 and do not conduct with each other.

However, when the bag 2 is placed on the surface of the water to be detected, the bag 2 contains the sealed air 6 and the conductive liquid 5, so that the bag 2 floats on the water surface. Will be. If the weight of the bag 2 itself is neglected, the liquid level of the conductive liquid coincides with the detection-symmetric water level. When the fixing portion 2a is fixed to the inner wall of the water tank in this state, the liquid surface of the conductive liquid 5 rises with the rise of the water surface, and when the electrodes 3 and 3 are simultaneously immersed in the conductive liquid 5, the conductive liquid 5 The electrodes 3 and 3 are electrically connected to each other via the.

The fixed part 2a of the water level detector 1 constructed as described above is used by installing the electrode part in a landing well, a pump well or the like so as not to move up and down. This will be described with reference to FIG.

First, as shown in FIG.
Is lower than the bag 2, the conductive liquid 5
It accumulates at a lower position, and is electrically non-conductive (OFF) between the electrodes 3.

Then, the water level WL rises, and FIG.
As shown in the figure, when the height level of the electrodes 3 is reached, the soft film 2b at the lower part of the bag 2 is easily bent and pushed up by the water pressure, whereby the liquid level of the conductive liquid 5 also rises. Then, the electrodes 3 and 3 are immersed, and the electrodes 3 and 3 are electrically connected (ON). At this time, the upper pressure absorbing film 2c slightly expands, and the pressure rise of the internal air 6 is suppressed.

When the water level WL rises to a higher position and the entire water level detector 1 is immersed in water as shown in FIG. 1C, the conductive liquid 5 continues to immerse the electrodes 3 and 3, 3,
The state of electrical continuity (ON) continues between the three. Also,
Although the upper air 6 is compressed, the pressure absorbing film 2 </ b> C further expands and the air pressure rises to balance with the liquid pressure of the conductive liquid 5.

Then, the electrical state between the electrodes 3 and 3 is extracted as a signal to the outside by the lead wires 4 and 4. In this manner, the conductive / non-conductive state of the electrodes 3 and 3 is converted into an electrical signal. Thus, the water level can be accurately detected.

In the above embodiment, the fixing portion 2a is used as the bag body 2.
Although the example in which the soft film 2b below and the soft film 2c for absorbing pressure are connected above has been described, it is a matter of course that the entire bag body 2 may be made of a soft film such as thin rubber or vinyl.

Next, FIGS. 3 and 4 show examples of a stand-alone type water level detecting device provided with one water level detector 1. FIG.

That is, in this example, one water level detector 1 is incorporated in a protective body 10 where water can freely enter and exit to prevent inflow from coming into direct contact with the water level detector 1 and to prevent a change in water level. The water level is converted into an electric signal by the water level detector 1 and taken out to the outside by the lead wire cable 4, and the water level detector 1 is supported by using the support portion 11. Here, the protection body 10 is a frame body made of a plastic resin such as acrylic.

As described above, when the water level detector 1 is used alone, one set of ON or OFF signals can be taken out according to the water level. By using a plurality of single-type water level detectors having such a configuration and mounting them at different water level levels, it is possible to perform ON / OFF control of a pump having a plurality of water levels or to monitor the water level.

FIGS. 5 and 6 show a collective water level detecting device in which three water level detectors 1 are combined for detecting a low water level, for detecting a middle water level, and for detecting a high water level. The water level detector 1 is attached to a water tank via a mounting portion 21 at a target level position along the vertical direction inside the protection tube 20. The lead wires 4 are assembled together and taken out. Since the water level detectors 1 are all disposed in the protective tube 20, they are not affected by the inflow.

In this example, for example, in the case of a water supply pump, the pump is stopped at a low water level, and the pump is started at a high water level. Can be used to stop the pump and issue a low water warning at low water levels.

It is a matter of course that a plurality of pumps and complicated control operations can be performed by using a combination of more water level detectors.

[0027]

As described above, according to the present invention, since the electrodes and the conductive liquid are sealed in the bag, there is no possibility of poor conduction between the electrodes due to dirt or the like. In addition, since no mechanical operation is required, there is no malfunction due to inflow of dirt or driftwood in detecting the water level of sewage or rainwater, and a highly reliable water level detector having an extremely simple structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a water level detector showing one embodiment of the present invention.

FIG. 2 is a vertical sectional front view for explaining the operation of the water level detector.

FIG. 3 is a front view of a single type water level detector provided with one water level detector.

FIG. 4 is a vertical sectional front view of FIG. 3;

FIG. 5 is a front view of a collective water level detector including a plurality of water level detectors.

FIG. 6 is a longitudinal sectional front view of FIG. 5;

[Description of Signs] 1 Water level detector 2 Bag 2b Elastic body 2c Pressure absorbing film 3 Electrode 4 Lead wire cable 5 Conductive liquid 6 Air 10 Protective body 20 Protective tube

Claims (6)

[Claims] A pair of electrodes fixed in the vicinity of a water level detection position, a conductive liquid and air are sealed inside a sealed soft bag, and the bag floats on the surface of the water to be detected.
A water level detector characterized in that when the liquid level of the conductive liquid rises to the height of the pair of electrodes due to the rise of the water level, the electrodes are conducted to detect the water level. 2. A liquid having a density equal to or close to the density of water is used as the conductive liquid.
Water level detector as described. 3. The water level detector according to claim 1, wherein the bag is formed of a thin and soft rubber film or a synthetic resin film. 4. The bag according to claim 1, wherein an upper portion of the bag is formed of a pressure absorbing film which expands in response to pressure.
The water level detector according to any one of the above. 5. A protection body for allowing water to be detected to enter and exit water and preventing entry of foreign matter, and the water level detector according to claim 1 is provided inside said protection body. A water level detection device characterized by the above-mentioned. 6. A protection tube which is opened up and down, and a plurality of water level detectors according to claim 1 are provided inside said protection tube along a vertical direction. Water level detector.