JPH10300559A - Water level sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water level sensor by which a water level can be detected automatically and stably, by a method wherein the water level is detected on the basis of the up-and-down movement of a float, a control switch is operated and a sprinkling apparatus is controlled according to the detected water level. SOLUTION: A water level sensor is constituted of a sensor body 1A and of a water-level setting part 1B which is composed of a float guide 19 which is shaft-supported by one end of an inclination arm 7, so as to be freely rotatable and of a float 31 which s coupled to the float guide 19. A water level is detected on the basis of the up-and-down movement of the float 31, a control switch 3 is operated, and sprinkling apparatus is controlled according to the detected water level. The float 31 is composed of a lightweight substance such as a synthetic-resin foamed material, it is disk-shaped, and foamed polypropylene is used as a material. As a result since a system which detects the water level on the basis of the up-and-down movement of the float 31 is adopted, a malfunction due to dust particles or the like is small as compared with a system which uses an electrodes. The water level can be monitored automatically and stably, and a maintenance inspection is hardly required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level sensor mainly used for detecting a water level in a paddy field or the like and operating an irrigation device. For more information,
The control switch is operated (ON-OFF) by detecting the set water level such as the upper limit water level and the lower limit water level by the up and down movement of the float, and the control circuit of the irrigation device is opened and closed according to the detected water level condition. It relates to a water level sensor that controls the irrigation device (which emits a signal).

[0002]

2. Description of the Related Art Conventionally, various irrigation devices have been developed for automatically irrigating water by detecting the water level in a paddy field or the like, and various water level sensors have been developed for that purpose. As one of them, there is one that uses a conductivity of water to detect a current flowing between electrodes to operate a switch (for example, JP-A-57-51319).

[0003]

The water level sensor disclosed in the above publication is provided with an electrode plate as a water level detection unit. However, since the water level sensor is installed in farmland, the electrodes become dirty or the electrodes become dirty. There is a risk of malfunction such as a short-circuited state between dust and the like containing moisture, so that it is considered necessary to frequently perform maintenance and inspection.
In addition, it is impossible to directly control the irrigation device with a weak signal detected by the electrode, and signal processing means for amplifying the signal to a controllable level or converting the signal to a controllable signal is required separately. It is considered that the cost may increase as a result. The present invention has been made in view of the above-described problems of the related art, and provides a water level sensor that can automatically and stably detect a water level, hardly requires maintenance and inspection, and as a result, can be implemented at low cost. It is intended to do so.

[0004]

According to the present invention, there is provided a water level sensor comprising a cylindrical case, a control switch housed in the cylindrical case and connected to a lead wire leading to an irrigation device, An operating rod, which is vertically movably held in the cylindrical case, for operating the control switch, and an arm rotatably connected to the upper end of the operating rod and supported by the cylindrical case so as to be vertically movable. And a water level setting section comprising a float guide rotatably supported at one end of the arm and a float engaged with the float guide, and the water level is detected by vertical movement of the float. The first feature is that the control switch is operated to control the irrigation device according to the detected water level.

A second feature is that the control switch and a connection portion between the control switch and a lead wire are hermetically sealed in a cylindrical case, and the control switch is constituted by a push-button switch. Third and fourth features are that an elastic body is attached to the lower end of the operating rod, and furthermore, an upper stopper and a lower stopper that can move up and down and can be fixed to the float guide according to the float guide. The float is loosely fitted to at least one of the float guide or the lower stopper, and a flange for positioning an upper limit water level provided at a lower end of the upper stopper and a lower limit water level provided for a lower end of the lower stopper are positioned. The fifth feature is that the second member is disposed between the second member and the flange.

[0006]

Embodiments of the present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a main part showing an embodiment of a water level sensor according to the present invention, FIG. 2 is a perspective view of a water level setting unit, and FIG. 3 is a longitudinal sectional view of a main part showing a state where the water level sensor detects a lower limit water level. FIG. 4 is a longitudinal sectional view of a main part showing a state in which a water level sensor detects an upper limit water level, FIG. 5 is an explanatory view showing a relationship between each terminal of a control switch and an internal circuit, and FIG. 7 is a circuit diagram showing a control relationship between the watering device and the water level sensor, and FIG. 7 is a circuit diagram showing a control relationship between the watering device and the water level sensor when the watering device is in a water supply state.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 1A is a sensor main body,
It is fixed using a fixed arm (not shown) in a dome-shaped protective container 2 installed with a reference surface aligned with a paddy field. The sensor body 1A has a control switch 3 housed in a vertically divided cylindrical protective case 5 and a lead wire 4 connected to an irrigation device 10 connected thereto. An operating rod 6 that is held and performs an ON-OFF operation in contact with and separated from the control switch 3, and an upper end of the operating rod 6 is rotatably connected to the operating rod 6 and is attached to an upper end of the protective case 5 so as to be tiltable up and down. And the tilting arm 7 provided. The following sensor body 1A
Will be described in detail.

In the figure, reference numeral 3 denotes a lower cylindrical portion 5 of the protective case 5.
This is a control switch fixed to the upper end of b. In this embodiment, a push-button switch in which two circuits (see FIG. 5) are provided is used. Here, the specification of the control switch 3 may be a rating sufficient for controlling the watering device 10 in consideration of the configuration of the control circuit and the electric capacity of the watering device 10. For example, if the irrigation device 10 is semi-automatic, one internal circuit may be used, and if the current flowing through the control circuit is about 100 mA, a low capacity type may be used. Reference numeral 4 denotes a lead wire that leads to an irrigation device 10 that is detachably connected to the lower end of the control switch 3 by a coupling 9. The connection of the lead wire 4 to the control switch 3 is not limited to the coupling method, and may be directly connected. The lead wire 4 is screwed via a gasket 11b into a screw hole 12a provided in the center of a holding plate 12 fixed to the lower end of the lower cylindrical portion 5b of the protective case 5 via a gasket 11a. The inside of the cable joint 13 is inserted through the packing 8.
Therefore, the connection between the control switch 3 and the lead wire 4 is sealed in the protective case 5.

The operating rod 6 is provided on the lower cylindrical portion 5 of the protection case 5.
b engaged with the gasket 14 on the upper lid 5a
It is held movably up and down through an O-ring 15. The upper end of the operating rod 6 is rotatably supported via a shaft pin 16 on a tilting arm 7 disposed longitudinally and laterally above the same upper lid 5a. A rubber ball 17 which is an elastic body for prevention is attached. Accordingly, the operating rod 6 and the contact portion 3a of the control switch 3 are also sealed in the hollow portion of the upper lid 5a.

The tilting arm 7 is provided with an upper cover 5 for the protection case 5.
The upper part 5a is arranged in the upper part 5a via a shaft pin 18 so as to be tiltable up and down. This shaft support position is different from the position of the shaft pin 16 on which the operating rod 6 is supported.
The tip of the tilting arm 7 is rotatably connected to a projection 20 provided on the float guide 19 via a shaft pin 21. Reference numeral 22 denotes a spring for causing the float guide 19 to perform a flip-flop type up / down operation. One end of the spring 22 is connected to the shaft pin 21, and the other end is connected to a fixing pin 23 protruding from the upper cover 5 a of the protective case 5. Has been stopped.

FIG. 2 is a perspective view of the water level setting section 1B.
The water level setting section 1B engages the long float guide 19 with a pair of stoppers 28 and 32 which can be moved up and down following the float guide 19, and the lower end of one of the pair of stoppers 28 and the other 32. Are provided at the lower ends of the flanges 30 and 34 for locking the float 31, respectively. The float 31 is movably engaged between the two flanges 30 and 34. Scales and numerals for setting the water level are engraved on the surface of the float guide 19, and grooves 24, 25 and 26, 27 for fitting two stoppers 28 and 32 are provided on both sides on both sides. Have been.

Reference numeral 28 denotes grooves 24 of the float guide 19,
An upper stopper slidably fitted to 25 has a screw 29 for fixing to the float guide 19 at an upper end thereof, and a flange 30 at a lower end thereof. In addition, although the flange 30 of the present embodiment is formed in a rectangular shape, the shape is not limited to this, and any shape may be used as long as the rising float 31 can be locked.

32 is a groove 26 of the float guide 19,
27 is a lower stopper slidably fitted to 27, and has a fixing screw 33 at an upper end and a flange 34 at a lower end. In addition, although the flange 34 of this embodiment is formed in a rectangular shape, the shape is not limited to this, and any shape may be used as long as it can lock the float 31 that descends.

Numeral 31 denotes a disk-shaped float made of a lightweight material such as a synthetic resin foam material. In this embodiment, foamed polypropylene is used as the material of the float.
Here, if the float 31 completely floats on the water,
Since the flange 34 of the lower stopper 32 cannot be pushed down, it is preferable to use a material having a specific gravity slightly lower than that of water. For this reason, polypropylene having a low expansion ratio is used for the float 31 of this embodiment. That is, as shown in FIGS. 3 and 4, the lower portion of the float 31 is below the water surface, and the upper portion is above the water surface. At a substantially central portion of the float 31, a rectangular through hole 35 is provided, through which the float guide 19 and the lower stopper 32 are inserted. The through-hole 35 needs to be sufficiently opened so as not to come into contact with the float guide 19 or the like and hinder the vertical movement of the float 31. The shape is not limited, and may be any shape as long as the float 31 is loosely fitted to the float guide 19 or the like. The material of the float 31 may be selected from materials that generate an appropriate buoyancy for the liquid to be controlled, in addition to the foamed polypropylene.

In the present embodiment, the float 31 is loosely fitted to both the float guide 19 and the lower stopper 32. However, the float 31 may be loosely fitted to only the lower stopper 32, and the operation of the float 31 may be loose. It is exactly the same as when fitted.

The operation of the water level sensor according to the present embodiment having the above-described configuration is as follows. FIG. 3 shows a state where the water level has reached the lower limit water level B. Water supply is continued from this state, and when the water level rises to the set upper limit water level A, the float 31 also rises accordingly, and the upper stopper 28
Abuts on the collar 30 of. The float 31 is further moved by the buoyancy together with the upper stopper 28 and the float guide 19.
Is pushed upward, and the tilting arm 7 interlocked with this
Tilts counterclockwise about the axis 18 and reaches the position shown in FIG. On the other hand, the operating rod 6 moves downward with the movement of the tilt arm 7, and the rubber ball 17 attached to the lower end of the operating rod 6 presses the control switch 3. That is, the control switch 3 is activated (ON).

Conversely, the water level falls and the set lower limit water level B
Is reached, the float 31 is also moved down to contact the flange 34 of the lower stopper 32. Since the float guide 19 moves downward due to its own weight and the load of the float 31, the tilt arm 7 associated therewith tilts clockwise about the shaft pin 18 and reaches the position shown in FIG. The operating rod 6 moves upward with this operation.
As a result, the rubber ball 17 attached to the lower end of the operating rod 6 moves upward and separates from the control switch 3 with which it is in contact. That is, the control switch 3 is returned (OFF).

Next, an example of a control method using the water level sensor according to the present invention as a water level detector of the irrigation apparatus 10 will be described. FIG. 5 shows the relationship between each terminal of the control switch 3 of the water level sensor and the internal circuit. Two circuits are built in, and the contacts DE at startup (ON)
Short-circuit between GH and GH, and contact D-
It is configured to short-circuit between F and GI.

FIGS. 6 and 7 are control circuit diagrams showing the control relationship between the watering device 10 and the water level sensor. When the water level of the paddy field reaches the set upper limit (the state of FIG. 4), the control switch 3 is activated (ON) as described above, and the contacts DE are set.
Short circuit between GH and GH to form a closed circuit DEJKNOPHG (FIG. 6). In this state, current flows in the direction of the arrow, and the motor 36 in the watering device 10 rotates to put the watering device 10 in a water-stop state. Conversely, when the water level reaches the set lower limit (the state of FIG. 3), the control switch 3 is reset (OFF) as described above, and the contacts DF and GI are short-circuited, and the DFHPONMLIG is closed. Circuit (Fig. 7)
Is configured. In this state, the current flows in the direction of the arrow (the direction opposite to that in FIG. 6), and the motor 36 rotates in the direction opposite to that in FIG. 6 to bring the irrigation device 10 into the water supply state.

Therefore, the control switch 3 in the water level sensor in the present control has a role of switching the rotation direction of the motor 36 in the watering device 10 according to the state of the water level. As described above, when the water level sensor according to the present invention is used, the upper limit water level and the lower limit water level are detected, the control switch 3 is operated, and the irrigation device 10 is controlled, so that the set water level of a paddy field or the like is always maintained. Can be.

Next, a case where the set value of the upper limit water level or the lower limit water level is changed will be described. When changing the upper limit water level, the fixing screw 2 of the upper stopper 28 in FIG.
By loosening 9, the upper stopper 28 is moved to a desired setting position along the scale engraved on the float guide 19, and is fixed at that position by tightening the fixing screw 29. On the other hand, when changing the lower limit water level, the lower stopper 32 is moved to the desired setting position along the scale by loosening the fixing screw 33 of the lower stopper 32, and the position is changed by tightening the fixing screw 33. Fixed to.

[0022]

As described above, the present invention has the following excellent effects. (1). Since the water level is detected by the vertical movement of the float, there is less erroneous operation due to dust, etc. compared to the method using electrodes, and the water level can be monitored automatically and stably, and maintenance is possible. Inspection is almost unnecessary. (2). Since the control switch and the connection between the control switch and the lead wire are sealed in the protective case, the control switch itself does not need to be provided with a separate waterproof structure. Product) can be used as it is and can be manufactured at low cost. (3). By selecting a push-button switch that matches the specifications of the control circuit configuration and electric capacity of the irrigation device,
Since the irrigation device can be controlled directly by the current flowing through the control switch, it is necessary to provide a separate signal processing circuit that processes the output of the control switch to a level that can be controlled by the irrigation device, as in the case of an electrode type water level sensor. There is no. (4). Since a wide variety of off-the-shelf switches are available on the market, even if the specifications of the irrigation device are changed, it can be easily replaced with a suitable one. Therefore,
Various watering devices can be used without changing the basic configuration of the water level sensor.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a main part of an embodiment of a water level sensor according to the present invention.

FIG. 2 is a perspective view of a water level setting unit.

FIG. 3 is a vertical sectional view of a main part showing a state in which a water level sensor detects a lower limit water level.

FIG. 4 is a vertical sectional view of a main part showing a state where a water level sensor detects an upper limit water level.

FIG. 5 is an explanatory diagram showing a relationship between each terminal of a control switch and an internal circuit.

FIG. 6 is a circuit diagram showing a control relationship between the watering device and the water level sensor when the watering device is in a water stop state.

FIG. 7 is a circuit diagram showing a control relationship between the watering device and the water level sensor when the watering device is in a water supply state.

[Explanation of symbols]

 Reference Signs List 1A Sensor main body 1B Water level setting section 2 Protective container 3 Control switch 3a Contact section 4 Lead wire 5 Protective case 5a Upper lid section 5b Cylindrical section 6 Operating rod 7 Tilt arm 8 Packing 9 Coupling 10 Irrigation device 11a Gasket 11b Gasket 12 Holding plate 12a Screw hole 13 Cable joint 14 Gasket 15 O-ring 16 Shaft pin 17 Rubber ball (elastic body) 18 Shaft pin 19 Float guide 20 Convex part 21 Shaft pin 22 Spring 23 Fixing pin 24 Stopper fitting groove 25 Stopper fitting Groove 26 Stopper fitting groove 27 Stopper fitting groove 28 Upper stopper 29 Fixing screw 30 Flange 31 Float 32 Lower stopper 33 Fixing screw 34 Flange 35 Through hole 36 Motor

Claims (5)

[Claims] 1. A protection case, a control switch housed in the protection case and connected to a lead wire leading to an irrigation device, and a control switch movably held up and down in the protection case. A sensor main body comprising an operating rod, an arm rotatably connected to the upper end of the operating rod and supported vertically by the protective case, and rotatably supported by one end of the arm; It has a water level setting unit consisting of a float guide and a float engaged with the float guide, detects a water level by moving the float up and down, activates a control switch, and controls the irrigation device according to the detected water level. Characterized water level sensor. 2. The water level sensor according to claim 1, wherein the control switch and a connection between the control switch and a lead wire are sealed in a protective case. 3. The water level sensor according to claim 1, wherein the control switch is a push button switch. 4. The water level sensor according to claim 1, wherein an elastic body is attached to a lower end of the operating rod. 5. An upper stopper and a lower stopper which can move up and down and can be fixed to the float guide in accordance with the float guide, wherein the float is loosely fitted to at least one of the float guide and the lower stopper, and 5. A flange provided at a lower end of the stopper for positioning an upper limit water level and a flange provided at a lower end of the lower stopper for positioning a lower limit water level. Water level sensor.