JPS6089718A - Water level detector - Google Patents

Abstract

PURPOSE:To detect variation in water level without any influence of moisture and dew condensation by attaching a Hall element to either of a movable and a fixed piece, and fitting a magnet which supplies a magnetic field to the Hall element at right angles to the direction of its control current to the other. CONSTITUTION:The Hall element HE is attached to either of the movable piece 7 which moves corresponding to water level variation and the fixed piece 25 which does not move regardless of the water level variation. The magnet 28 which supplied the magnetic field to the Hall element HE at right angles to the direction of its control current is fitted to the other. The water level variation is detected from variation in the output voltage perpendicular to the control current direction of the Hall element HE and magnetic field direction.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a water level detection device that detects changes in water level in a water tank of a washing machine or the like as a continuous electrical signal.

<Prior Art> Conventionally, as water level detection devices, devices using float switches, water electrodes, the weight of water, or the capacitance in a water tank have been used. The water level detection device using a diaphragm was the first.
It has the structure shown in the figure.

In Fig. 1, 1 is a water tank, 2 is water in the tank,
Reference numeral 3 denotes a communication pipe that communicates the bottom opening 1a of the water tank 1 with the opening 5a of the case 5. 4 is air, 6 is outer periphery case 5
7 is a movable piece fixed to the movable valve 6 and moves in conjunction with the movable valve 6, and 9 is a compression type main spring inserted into the cylindrical portion 8a of the lid 8. Reference numeral 1( ) is a spring retainer that presses the main spring 9 toward the movable piece 7, and reference numeral 11 is an adjustment screw screwed into the left end of the cylindrical portion 8a. 12 is a normally closed contact, 13 is a movable contact, 14 is a normally closed contact, and these are the lid 3;
The movable contact 13 is engaged with the movable piece 7. In this configuration, when water 2 is poured into the water tank 1, the air 1 in the chamber surrounded by the water surface 2a in the communication pipe 3, the case 5, and the diaphragm 6 is compressed and presses the movable valve 6, and the pressure increases at the water level. That is, it is proportional to the 1-downward displacement of the water surface 2a.

When the adjustment screw 11 is turned, the spring holder 10 presses the main spring 9,
Until the spring pressure is applied to the movable piece 7, the pressure of the main spring 9 is greater than the pressure of the air 4, and neither the movable valve 6 nor the movable piece 7 moves, until water enters a certain predetermined water level. The movable contact 13 is in contact with the normally closed contact 12. When the water level reaches a predetermined level, the pressure of the air 1 overcomes the pressure of the main spring 9, causing the movable valve 6 and the movable piece 7 to move leftward to the external movable contact 1.
3 is connected to the normally open contact 14.

- Adjustment screw 1 for water level detection devices with structure 2.
1 has the disadvantage that it can only detect at a fixed point whether the water level has reached a mechanically set level.

<Objective> The object of the present invention is to provide a water level detection device capable of detecting a wide range of water levels as a continuous electric signal using the Hall element described above.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 2 to 5. 1 is a water tank, 2 is water in the water tank, 3 is a communicating pipe,
The bottom opening 1a of the case 5 is in communication with the opening 5a of the case 5. 4 is a diaphragm movable valve whose outer periphery is held between the case 5 and the lid 8, 7 is a movable piece fixed to the movable valve 6 and moves in conjunction with this, and 9 is a compression type main spring 9, which is movable. The stepped portion 7b, which is the vertical portion of the small diameter portion 7a of the piece 7, and the cylindrical portion 8 of the lid 8.
It is interposed between the inner surface 20a of the left end portion of the cylindrical hole 20 that is slidably fitted inside the hole 20a. Reference numeral 21 denotes a support whose right end is fixed to the case 5 with a screw 22, and a pin-shaped fixing piece 25 is fixed to the left end of the support by a Hall element position adjustment screw 23 and an adjustment spring 24 so that the horizontal position can be adjusted freely. be done. The right portion of the fixing piece 2S is inserted into the holder 20 through its hole 20cJ. Further, a main spring adjustment screw 2G is screwed into the support body 21.
The protruding piece 201) of the holder 20 is brought into contact with the tip of the holder 6,
A balance spring 27 for adjustment screw 2G is interposed between the protrusion 201J and the lid 8.

A Hall element HE is mounted on one of the movable piece 7 that moves in response to changes in the water level and the fixed piece 25 that does not move due to the change in water level, and the capacity of the movable piece 7 and the fixed piece 25 is , a magnet 2 for applying a magnetic field l) to the Hall element HE in a direction perpendicular to the direction of its control current I;
8 is attached, and is configured to detect a change in water level based on a change in the output voltage V in a direction perpendicular to the direction of the control current and the direction of the magnetic field of the Hall element HE.

In addition, in Fig. 4, to explain the Hall effect in the Hall element HE, a control current
When a magnetic field of bCWb/I+12] is applied in the direction perpendicular to this current I, the free electrons receive a force in the Y direction perpendicular to both I and [). It gathers at the terminal T1 and generates a potential difference between T1 and 12, that is, a Hall voltage V (T2 is positive, T1 is negative). (In addition, when the semiconductor is P-type, the genuine tag gathers on the T1 side.) V=Rh-b・1/l However, RI+: Hall coefficient Furthermore, in this embodiment, the Hall element HE is placed at the right end of the fixed piece 25.
Although the magnets 28 are attached to the left end of the movable piece 7, it is clear from the description of FIG. 4 that they may be attached to opposite sides. In addition, in Fig. 2, 29 is the electric circuit unit of the water level detection device, 31) is its wiring,
51] is a stopper formed in the case 51.

- When water 2 is poured into the water tank 1, the air 4 in the chamber surrounded by the water surface 2a in the communication pipe 3, the case 5, and the diaphragm 6 is compressed and presses the movable valve 6, and the pressure increases as the water level increases. It is proportional to the downward displacement of the water surface 2a. Note that when the adjustment screw 26 is turned, the spring 20 pushes the main spring 9,
Since the spring pressure is applied to the movable piece 7, the pressure of the spring is less than the pressure of the air 4 up to a certain water level, the movable valve 6, the movable piece 7, and the magnet 28 do not move, and the magnetic flux density does not change. Therefore, the output voltage V of the Hall element tlE does not change. When that water level is exceeded, the pressure of the air 4 overcomes the pressure of the main spring 9, causing the movable valve 6, the movable piece 7 and the magnet 2 to move.
8 moves, which causes a change in magnetic flux density, so
The output voltage V of the ball element HE changes.

In FIG. 2, when the water level rises, the magnet 28 moves to the left and approaches the Hall element HE, so the magnetic flux density increases1) and the output voltage V increases. The water level is hem, the density of water is g/c
m3, the pressure receiving area of the movable valve 6 is 5 cm2, and the spring coefficient of the main spring 9 is 'g/co+, then the crab F1 of the air 4 pushing the movable piece 7 to the left with the water level detection device horizontal is F1 =HG-8. Further, if the length of contraction of the main spring 9 is ρcm, the crab F2 applied to the main spring 9 is expressed as F2=−ρ. When F1=F2, the horizontal force applied to the movable piece 7 is balanced, but the stroke 2ρ0 of the adjustment screw 16 for a certain water level hO should be 1+0・G−3=1ρ(). Once determined, the water level 11≦11 (in the range of 1, the magnetic flux density 1+=bO (initial value) remains, so the output voltage of the Hall element I]E remains V-\'0 (initial value).

In the range of water level b > It +'l, the output voltage V of the Hall element HE changes.
It is proportional to the water level change in och-hO. (See Figure 4) Therefore, if the spring coefficient and the area of the movable valve 6 are appropriately selected, an arbitrary water level 1]0 can be set with the adjustment screw 26, and the water level change for water levels higher than that can be controlled by the Hall element I ( It can be continuously detected as a change in the output voltage \7 of E.

Next, a method for adjusting the positions of the magnet 28 and the Hall element HE will be explained. First, when the water level is zero (the air pressure inside the communication pipe 3 is equal to atmospheric pressure), use the adjustment screw 26 for the main spring 9 to tighten the movable valve 6.
is in contact with the stopper 51) of the case 5, turn the Hall element position adjustment screw 23 to move the Hall element HE to the right, and adjust the output voltage to \"2vO (initial value). Next, when the water level h = It 0, the magnet 23 moves and the output voltage of the Hall element 1-IE increases, so turn the adjustment screw 26 of the main spring 9 to adjust the Hall element 1-IE. The main spring 9 pushes back the magnet 28 so that the output voltage of the Hall element 1 (E becomes \7-\"0." The initial value of can be easily adjusted.

To explain the electric circuit of the water level detection device in Fig. 3, the part surrounded by the dotted line is the detection circuit section including the Hall element HE and the resistor R1, which applies a DC voltage between points A and C (between points D and E). Apply. ICI to IC4 are comparators, R2 to R12ii
Resistance, VRii-variable resistance, LED1~LED4
is a light emitting diode, Ql is a transistor, D2 is a diode, and RY is a relay. As mentioned above, the output voltage V (voltage at point B) of the control current ■ of the Hall element 1-IE determined by the power supply voltage and the resistance R1 is \"=RII-b-I/l, and the output voltage \l is the magnetic flux. It is taken out as a DC voltage signal proportional to the change in density.The part outside the dotted line in Figure 3 is the water level display and relay drive circuit.As the water level rises, the output voltage at point B \711 becomes D- Let the power supply voltage between point E be \゛S, and let the values of resistors R2 to R5 be R2, respectively.
-R5, then the output of the comparator ICI becomes I, the signal 1. Er) I lights up, and when it becomes , the output of hump parator IC2 becomes a signal and LED2 lights up, and when it becomes , the output of hump parator IC3 becomes an L signal and becomes L.
ED 3 lights up. Also variable resistor ＼°R and resistance.

If the output voltage V It at point B is smaller than the voltage division with resistor R13, the output of comparator TC4 is the I-1 signal) Run E; Star QI is ON, 'JL/-1<Y is also ON cL
ED, 1 lights up. Conversely, when it increases, the output of comparator TC4 becomes an H signal and transistor Q1 turns OFF.
F L, at the same time as relay RY turns off, L E D
4 goes out. In other words, if the normally open contact of relay RY drives the water supply solenoid or water supply pump, LED4 will indicate that water is being supplied, and LEDI, I.

ED2.1. , ED 3 depends on displaying the water level. In Figure 3, LED] ~ L E D 3
Three cases have been shown, but since the output signal is continuously output, it can be easily A/D converted by a microcomputer or the like and displayed in fine increments.

<Effects> In the present invention, a Hall element is attached to one of a movable piece that moves in response to a change in water level and a fixed piece that does not move due to a change in water level, and the other of the movable piece and the fixed piece,
A magnet for applying a magnetic field in a direction perpendicular to the direction of the control current is attached to the Hall element, and a change in water level is detected by a change in output voltage in a direction perpendicular to the direction of the control current and the direction of the magnetic field of the Hall element. It is constructed.

In other words, since the present invention converts changes in water level into changes in magnetic field, the water level detection device can detect changes in water level without being affected by humidity or condensation. It has the excellent effect of being very effective as a water level detection device for washing machines and baths.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional device, Fig. 2 is a sectional view of an embodiment of the present invention, Fig. 3 is an electric circuit diagram of the same, Fig. 1 is a functional explanatory diagram of a Hall element, and Fig. 5 is a diagram of a Hall element. It is a diagram showing the relationship between output voltage and water level. 1: Water tank, 2: Water in the tank, 3: Communication pipe, 4: Air, 5
: Case, 6: Movable valve, 7: Movable piece, 8: Lid, 1]: Main spring, 25: Fixed piece, 28: Magnet, IIE: Hall element, ■2 Control current, ~": Output voltage, 1) : Magnetic field. Applicant: Sharp Corporation Agent Tsunehisa Nakamura

Claims (1)

[Claims] A Hall element is attached to one of a movable piece that moves in response to a change in water level and a fixed piece that does not move in response to a change in water level. A magnet is attached for applying a magnetic field in a direction perpendicular to the direction of the magnetic field, and the water level change is detected by a change in the output voltage in a direction perpendicular to the direction of the control current of the Hall element and the direction of the magnetic field. water level detection device.