JPH05161588A - Water level detector for dish washer - Google Patents

Abstract

PURPOSE:To detect a water level at the bottom of a washing tank linearly and at a high accuracy. CONSTITUTION:A float box 7 is provided communicating with the bottom of a washing tank 1 built in a dish washer and a float 12 is so arranged in the float box 7 to move vertically through a washing water 2. An encoder 13 for detecting a water level is at the upper end of a working shaft 12a of the float 12 and moves vertically together with the float 12 corresponding to changes in the water level. Moreover, a photointerruptor 14 is arranged below an upper end opening of a pipe 9 for supporting the float in the float box 7 as opposed to the encoder 13 and detects the position of the float 12 through the encoder 14.

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 for a dishwasher which detects the level of washing water supplied to a washing tank to wash dishes, and more particularly to a dishwasher with high detection accuracy. The present invention relates to a water level detection device.

[0002]

2. Description of the Related Art Conventionally, in a dishwasher, a float switch or a pressure switch has been used as a means for detecting the level of washing water in a washing tank. When the tap water is supplied as cleaning water into the cleaning tank, these detection switches detect that a predetermined water level has been reached and close the on-off valve such as a water supply solenoid valve to stop the water supply. As a conventional water level detection device for this type of dishwasher,
The technique disclosed in Japanese Utility Model Publication No. 59-2764 is disclosed. This is because the washing water level tank communicating with the washing tank and the overflow tank communicating with the inner tank above the filter are provided, and the water level detecting means is provided in each tank, thereby clogging the filter or the water level of the washing water. It is possible to reliably prevent water leakage due to a failure of the detection means.

[0003]

However, in general, the pressure switch has a large error and is not accurate. In addition, the float switch cannot usually grasp the change in water level linearly. However, if necessary,
In some cases, an optical sensor such as a photo interrupter was attached to the float switch so that the water level could be grasped linearly. However, when an optical sensor is used, heated cleaning water vapor may leak to the outside through the upper opening of the float switch and adhere to the light emitting surface and light receiving surface of the optical sensor, resulting in malfunction. It was

Therefore, an object of the present invention is to provide a water level detecting device for a dishwasher which can detect the water level of the cleaning water in the lower part of the cleaning tank linearly and accurately.

[0005]

A water level detecting device for a dishwasher according to the present invention includes a float box provided in communication with a lower portion of a washing tank built in the dishwasher, and a float box provided in the float box. A float that is installed and moves up and down through cleaning water, an encoder that is attached to the upper part of the float and that moves up and down together with the float in response to changes in the water level, and an opening at the upper end of the float box The detector is disposed below the encoder so as to face the encoder and detects the position of the float via the encoder.

[0006]

In the present invention, since the encoder for detecting the water level which moves up and down integrally with the float corresponding to the fluctuation of the water level is attached to the upper portion of the float, and the detector is attached opposite to this encoder, the change in the water level is caused. Can be detected linearly. Then, the vapor that leaks outside from the upper end opening of the float box is scattered upward, but since the detector that detects the position of the float via the encoder is arranged below the upper end opening of the float box, The generated vapor does not adhere to the detector, and as a result, the detector does not malfunction.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a partially cutaway front view showing a state of a water level detector for a dishwasher according to an embodiment of the present invention at a low water level, and FIG. 2 is a partially cutaway front view showing a state at a high water level of FIG. 1, FIG. 3 is a perspective view showing the water level sensor of FIG.

In the figure, 1 is a washing tank built in a dishwasher main body (not shown), 2 is stored in the lower portion of the washing tank 1,
Washing water for washing dishes (not shown) disposed inside the washing tank 1, 3 is a water supply pipe for supplying tap water to the inside of the washing tank 1, and 4 is a tap water supply passage. Is a solenoid valve for water supply for opening and closing, and 5 is a drain pipe for discharging the wash water 2 in the lower part of the wash tank 1 to the outside, and 6 is a drain pump. Reference numeral 7 is a float box provided in communication with a lower portion of the cleaning tank 1 through a connecting pipe 8, and 9 is a float supporting pipe vertically attached in a hermetically sealed state to a round hole formed in the upper surface of the float box 7. is there.

Reference numeral 11 denotes a water level sensor provided in the float box 7, reference numeral 12 is provided inside the float box 7, and a float that moves up and down according to the water level of the cleaning water 2 is provided.
Reference numeral a denotes an actuating shaft vertically attached to the center of the float 12, which can move up and down inside the float supporting pipe 9. Reference numeral 13 is an encoder attached to the upper end of the operating shaft 12a of the float 12, the overall shape of which is a U-shaped plate, and a plurality of square hole-shaped slits 13a are formed at predetermined positions on both side surfaces thereof. .. Reference numeral 14 denotes a plurality (four in the figure) of photointerrupters arranged to face the slits 13a on both sides of the encoder 13, each of which is composed of a pair of a light emitting element and a light receiving element sandwiching the slit 13a of the encoder 13. Has been done. Then, the presence or absence of the shield of the encoder 13 is detected and the signal is sent to a control circuit (not shown). The slits 13a provided in the encoder 13 are formed at positions different from each other, and the position of the float 12 can be specified by combination with the plurality of photo interrupters 14.

Next, the operation of the water level detecting device of the dishwasher of this embodiment having the above-mentioned structure will be described. First, when tap water is supplied to the inside of the cleaning tank 1 as the cleaning water 2 before cleaning, the float 12 of the water level sensor 11 is located at the lowest point, and at the same time, is integrated with the float 12. The encoder 13 is also located at the lowest point. The photo interrupter 14 faces the uppermost slit 13a of the encoder 13, and the uppermost slit 13a.
The detection signal a is sent to a control circuit (not shown). The control circuit that receives this signal issues an opening command to the water supply solenoid valve 4. As a result, the water supply solenoid valve 4 is opened, and tap water is supplied into the cleaning tank 1 through the water supply pipe 3.

When the washing water 2 is stored in the lower portion of the washing tank 1 to some extent, the washing water 2 enters the float box 7 through the connecting pipe 8 and pushes up the float 12 by buoyancy. Along with this, the encoder 13 also rises integrally, and as shown in FIG. 1, the photo interrupter 14 faces the slit 13a slightly lower than the slit 13a at the uppermost stage, detects this, and outputs a signal. .. Subsequently, as the cleaning water 2 is supplied and the amount of the cleaning water 2 stored in the lower part of the cleaning tank 1 increases, the float 12 of the water level sensor 11 is further pushed up in the same manner, as shown in FIG. The photo interrupter 14 faces the lower slit 13a, and sends a detection signal corresponding to the slit 13a to the control circuit. Then, when the cleaning water 2 rises to the upper limit set water level and the photo interrupter 14 faces the lowermost slit 13a of the encoder 13 corresponding to the upper limit set water level, the control circuit inputs this signal to the water supply solenoid valve 4. A supply stop command signal is sent, the water supply solenoid valve 4 is closed, and water supply is stopped.

The encoder 13 is formed with a plurality of slits 13a, and the water level sensor 11 can send a detection signal linearly corresponding to the water level of the wash water 2 at an arbitrary position. It is possible to detect an abnormal lowering of the water level inside, and it is also possible to arbitrarily change the water level condition setting.

On the other hand, in cleaning, since the cleaning water 2 is heated to improve the cleaning ability, steam is also diverged from the liquid surface of the float box 7, as shown by the broken line arrows in FIGS. 1 and 2. , Flows upward through the float support pipe 9 and leaks to the outside from the upper end opening. However, since the photo interrupter 14 is disposed below the upper end opening of the float supporting pipe 9, vapor hardly adheres to the light projecting surface and the light receiving surface. As a result,
Since the photo interrupter 14 does not malfunction,
The supply of tap water can be reliably stopped at the set water level.

As described above, the water level detecting device for the dishwasher according to the above-described embodiment has the float box 7 provided in communication with the lower portion of the washing tank 1 built in the dishwasher, and the float box 7 in the float box 7. A float 12 which is disposed and moves up and down through the cleaning water 2, and an operating shaft 12a of the float 12.
An encoder 13 for detecting the water level, which is attached to the upper end of the float and moves up and down integrally with the float 12 in response to fluctuations in the water level.
And the float support pipe 9 of the float box 7
The photo interrupter 14 is disposed below the upper end opening of the above so as to face the encoder 13 and detects the position of the float 12 via the encoder 13.

Therefore, according to the above embodiment, the encoder 13 for detecting the water level, which moves up and down integrally with the float 12 in response to the fluctuation of the water level, is attached to the upper part of the float 12,
The photo interrupter 14 is opposed to the encoder 13.
Since it is attached, it is possible to detect changes in water level linearly. The wash water 2 leaked to the outside from the upper end opening of the float support pipe 9 of the float box 7.
Although the steam of the above is scattered upward, since the photo interrupter 14 for detecting the position of the float 12 via the encoder 13 is arranged below the upper end opening of the float supporting pipe 9 of the float box 7, the leaked cleaning water The second vapor does not adhere to the photo interrupter 14. As a result, malfunction of the photo interrupter 14 can be prevented, and detection accuracy can be improved. Further, in this embodiment, since the optical switch of the photo interrupter 14 is used as the detector, the structure of the water level sensor 11 as a whole is simple and the mounting space is small.

By the way, a total of four photo interrupters 14 are mounted facing the slits 13a of the encoder 13 in the above embodiment.
The number is not limited to this, and an arbitrary number may be attached according to the detection accuracy and the number of set conditions. In the above embodiment, the encoder 13 is attached to the float 12 and the position of the slit 13a is detected by the photo interrupter 14 to detect the water level in the cleaning tank 1. However, the present invention is embodied. In this case, the detection means is not limited to the optical switch, but may be, for example, a contact detection means using a limit switch. And even in this case,
By arranging the detector below the upper end opening of the float box 7, the steam of the cleaning water 2 leaking from the upper end opening of the float box 7 may adhere to the detector and malfunction, or rust may occur. It is possible to prevent the malfunction.

[0017]

As described above, the water level detecting device for a dishwasher according to the present invention is provided with a float box provided in communication with a lower portion of a washing tank built in the dishwasher, and a float box provided in the float box. A float that is installed and moves up and down through cleaning water, an encoder that is attached to the upper part of the float and that moves up and down together with the float in response to changes in the water level, and an opening at the upper end of the float box The detector is disposed below the encoder so as to face the encoder and detects the position of the float via the encoder. Therefore, the change in the water level can be detected linearly by the encoder for detecting the water level, which moves up and down integrally with the float in response to the change in the water level above the float, and the detector facing the encoder. Then, the steam leaked to the outside from the upper end opening of the float box is scattered upward, but since the detector for detecting the position of the float via the encoder is arranged below the upper end opening of the float box, the leakage is prevented. The vapor of the washing water does not adhere to the detector, and as a result, malfunction of the detector can be prevented and detection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a state of a water level detecting device for a dishwasher according to an embodiment of the present invention at a low water level.

FIG. 2 is a partially cutaway front view showing a state at a high water level in FIG.

3 is a perspective view showing the water level sensor of FIG. 1. FIG.

[Explanation of symbols]

 1 Cleaning Tank 7 Float Box 12 Float 13 Encoder 14 Photointerrupter

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshitaka Yajima 1-3 Komaba-cho, Nakatsugawa-shi, Gifu Mitsubishi Electric Corporation Nakatsugawa Works (72) Inventor Masaharu Ohori 1-3-3 Komaba-cho, Nakatsugawa-shi, Gifu Mitsubishi Electric Nakatsugawa Manufacturing Co., Ltd. (72) Inventor Kiyoshi Nakamura 1-3 Komaba-cho, Nakatsugawa-shi, Gifu Mitsubishi Electric Corporation Nakatsugawa Manufacturing Co., Ltd. (72) Naoki Nishio 1-3-3 Komaba-cho, Nakatsugawa-shi, Gifu Mitsubishi Electric Corporation Nakatsugawa Works

Claims (1)

[Claims] 1. A float box provided in communication with a lower portion of a washing tank built in a dishwasher, a float disposed in the float box, which moves up and down through washing water, and a float of the float. An encoder for water level detection that is attached to the upper part and moves up and down integrally with the float in response to changes in water level, and below the upper end opening of the float box,
A water level detection device for a dishwasher, comprising: a detector that is disposed so as to face the encoder and that detects the position of the float via the encoder.