JPH04164431A - Dish washing machine - Google Patents

Abstract

PURPOSE:To drain water certainly and prevent water leak from the body by making abnormality information about overflowing when a float switch is put on, and actuating a water drain means for a certain period of time. CONSTITUTION:When the pressure 13 applied to a diaphragm 12 of a water level sensing means 6 in proportion to the water level changes, a magnetic substance 14 displaces in vertical direction while receiving the action of a spring 16. At this time, the magnetic substance 14 displaces in a coil 15, so that its inductance changes to cause change in the frequency. The relation of the water level to the frequency becomes one to one, and if the water level at any time is to be sensed, the frequency at the time can be sensed instead. If h1 is assumed as the washing water level at the designing and h2 as the overflow level at designing, h2' is exceeding the overflow surface of a tank. A float switch furnished at the bottom of the body senses the intra-tank overflowing in this meaning, and the user is informed immediately by issue of an abnormality information. Thus water leakage from the body can be prevented by operating a water drain pump for a certain period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a dishwasher that performs a series of sequential washing, rinsing, and drying operations using control means.

BACKGROUND OF THE INVENTION In recent years, dishwashers have been designed to perform a series of sequential washing, rinsing, and drying operations using a microcomputer-based control device.

Conventionally, this type of dishwasher uses a pressure switch, a float switch, or the like as a water level detection means for detecting the level of water supplied into a tank. A pressure switch uses a diaphragm to receive pressure from an air trap that communicates with the bottom of the tank to open and close the contacts of the pressure switch, and a float switch applies magnetism to another tank that communicates with the bottom of the tank. A reed switch is opened and closed by moving the float according to the water level inside the tank.

Problems to be Solved by the Invention In such conventional dishwashers, in order to obtain the required water level, only one water level can be detected for each - number of water level detection means, so it is difficult to detect the number of water levels required. The same number of water level detection devices are required, and manufacturers usually use two water level detection means, one for the minimum required washing water level and one for the overflow water level, partly due to cost considerations. This washing water level is the basic water level required when washing or rinsing the dishes set in the tank. Also, the overflow water level refers to the so-called dangerous water level, where the water level in the tank exceeds the washing water level and if the water level rises any further, water may overflow from the tank and wet the kitchen floor.

This dangerous water level condition is caused by a malfunction of the water supply valve, etc.
This occurs when water that should normally be rising is still flowing out, and a width is set aside from the washing water level to prevent false detection. Therefore, this dangerous water level condition is usually set at a water level that is on the verge of tank overflow.

In addition, the dangerous water level detected by this water level detection means is only detected inside the tank, and water leaks from sources other than the tank (for example, water leaks due to poor tightening of the joint of the water supply pipe).
Recently, float switches are sometimes used for detection.

The overflow detection using this float switch also detects overflow from inside the tank, but originally overflow inside the tank is detected by the water level detection means before it overflows from the tank. However, when a pressure switch is used as the water level detection means, there is a problem in that the detected water level rises higher than the initial level due to deterioration and hardening of the diaphragm, making it impossible to detect a dangerous water level in the tank and potentially causing water to overflow. Ta. The present invention is intended to solve such problems, and its primary purpose is to issue an overflow warning and operate the drainage means for a certain period of time when a float switch provided at the bottom of the main body is activated. The second purpose is to ensure that water can be drained even if the water level in the tank that has already been drained rises again.

Means for Solving the Problems In order to achieve the above-mentioned first object, the present invention comprises: a water supply means for supplying water into a tank; and a first water level detection means for detecting the water level in the tank by water supplied from the water supply means. , a cleaning means for circulating the water supplied by the water supply means to wash the dishes set in the tank; a drainage means for draining the water in the tank; a second water level detection means for detecting water leakage inside the main body; an abnormality notification means for notifying in the event of an abnormality; and a second water level detection means for notifying the user when an abnormality occurs; and a control means that performs a series of sequential operations, and when the control means receives an output signal from the second water level detection means, the abnormality notification means notifies the abnormality and operates the drainage means for a certain period of time. This is how it was done.

Further, in order to achieve the second object, the control means of the present invention inputs the signal of the second water level detection means, and when the abnormality notification state is already in place, the control means receives the signal of the first water level detection means. The water level at which the drainage means is operated is set to be lower than the J predetermined water level.

According to the above structure, when a pressure switch is used as a means for detecting the water level in a tank, the detected water level rises higher than the initial level due to hardening due to deterioration of the diaphragm, making it impossible to detect a dangerous water level in the tank and causing overflow. Even if this occurs, a float switch located at the bottom of the main unit will alert you to an overflow condition, allowing you to drain the water inside the tank.

Further, according to the present invention, a float switch provided at the bottom of the main body is used to notify an overflow abnormality, and even if the water level rises again after the tank has been drained, the tank can be drained reliably.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

As shown in the figure, the control means 1 normally uses a microcomputer (hereinafter referred to as microcomputer).

This control means 1 controls opening and closing of a water supply means (hereinafter referred to as a water supply valve) 3 that supplies water to a tank 2.

The air trap 4 is formed at the lower side of the tank 2 and is connected to a first water level detection means 6 (hereinafter referred to as a pressure switch) via an air hose 5, so that the air pressure inside the air trap 4 changes depending on the water level. The structure is such that the water level is detected based on the The door 7 is used to take in and take out tableware. Further, there is a nozzle 9 at the bottom of the tank 2 for washing tableware, and the water in the tank 2 is circulated by a washing means (hereinafter referred to as a washing pump) 10 and is ejected from the nozzle 9. Water overflowing from the tank or leaking from inside the main body is detected by a second water level detection means 6' (hereinafter referred to as a float switch). A drainage means (hereinafter referred to as a drainage pump) 11 drains water after cleaning or when taking measures against flooding.

An embodiment of the pressure switch will be described with reference to FIGS. 3 to 5.

In FIG. 3, a diaphragm 12 is formed of a thin film material such as rubber, and a pressure 13 proportional to the water level in the tank 2 is applied thereto. A magnetic body 14 is fixed to the diaphragm 12 and is movable in the vertical direction inside the coil 15.

The spring 16 suppresses the displacement of the magnetic body 14, and the outer frame 17 is connected to the circumferential portion of the diaphragm 12 and the coil 15.
is fixed. Further, the coil 15 is connected to an inverter 18. as shown in FIG. Feedback resistance 19. Capacitor 20.
Together with 21, it forms an oscillation circuit.

In the water level detection means 6 configured as described above, when the pressure 13 applied to the diaphragm 12 changes in proportion to the water level, the magnetic body 14 is displaced in the vertical direction under the action of the spring 16. At this time, since the magnetic body 14 is displaced inside the coil 15, the coil 1
The inductance of 5 changes. Since the frequency of the oscillation circuit shown in FIG. 4 is determined by the inductance of the coil 15 and the capacitance of the capacitors 20 and 21, when the inductance of the coil 15 changes, the frequency changes. The relationship between water level and frequency is shown in a graph as shown in Figure 5. In other words, the relationship between water level and frequency is one to one.
Therefore, if we want to detect a certain water level, we only need to detect the frequency at that time.

Here, if water levels hl and h2 are set in FIG. 5, the corresponding frequencies fl.

f2 is determined. The control means 1 (microcomputer) reads this value and can detect the water level. In the above configuration, changes in water level detection in the tank will be explained with reference to FIGS. 2 and 6. Generally, diaphragms used in pressure switches are made of a thin film material such as rubber, and this rubber has the property of hardening when stress such as temperature or humidity is applied. Dishwashers are particularly susceptible to this effect because they use hot water. Therefore, even if pressure is applied to the diaphragm, it will not change while the pressure is low, and the water level will be higher than the originally set water level.

A' in FIG. 6 shows the relationship between water level and frequency when the diaphragm is hardened. Assuming that the diaphragm starts operating from the water level of hO, the microcomputer's detection frequencies fl and f2
does not change, so the water level changes from hl to hl' to h2
changes from h2' to h2'. In Figure 2, if hl is the design wash water level and h2 is the design overflow water level, then h2
'The tank is overflowing. If water enters the tank due to a malfunction in the water supply valve, the pressure switch will not be able to detect the overflow level and the water will overflow from the tank.

The float switch installed at the bottom of the main unit detects water overflow in the tank, alerts the user as soon as possible by reporting an abnormality, and prevents water from leaking from the main unit by operating the drain pump for a certain period of time. can.

Further, another embodiment will be described using FIG. 2.

As long as the diaphragm of the pressure switch is not hardened and the original water level can be detected, even if the water supply valve fails, the water in the tank can be drained by operating the drain pump at the h2 water level in the tank, so the water in the tank can be drained again. Even if the water level in the tank rises, water can be drained repeatedly at the same h2 water level.

However, as in the first embodiment, when the overflow detection water level reaches h2' due to hardening of the diaphragm, overflow is detected by the float switch and the tank can be drained, but the water level in the tank rises again. However, it is not possible to repeatedly detect the same h2' water level, and if the user does not notice this abnormality notification, the water will flow out from the main body onto the floor. Therefore, while the float switch is reporting an abnormality, by resetting the re-drainage detection water level using the pressure switch to a water level lower than the initially set h2 water level (for example, the h1 water level of the washing water level), It can be drained at

Due to the mechanism design, if the overflow water level h2 can be maintained with sufficient margin for the tank overflow surface, such control is not necessary.
In reality, many things were impossible.

More than the effects of the invention, as is clear from the examples, according to the present invention, when a pressure switch is used as a means for detecting the water level in a tank, the detected water level rises from the initial level due to hardening due to deterioration of the diaphragm. Even if the dangerous water level in the tank cannot be detected and the water overflows, the float switch installed at the bottom of the main unit will detect the overflow abnormality, notify the user as soon as possible, and drain the water inside the tank. can do.

Further, according to the present invention, a float switch provided at the bottom of the main body notifies the overflow abnormality, and even if the water level rises after the tank has been drained, the tank can be drained reliably.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a dishwasher according to an embodiment of the present invention.
Fig. 2 is a sectional view of the dishwasher, Fig. 3 is a sectional view of the water level detection means of the dishwasher, Fig. 4 is a circuit diagram of the water level detection means, and Fig. 5 is a characteristic diagram of the water level detection means. FIG. 6 is a characteristic diagram of the same water level detection means when the diaphragm is hardened. 1...control means, 2...tank, 3.
...Water supply means, 6...First water level detection means, 6'...Second water level detection means, 8...
...Abnormality notification means, 10...Cleaning means, 11.
... Drainage means. Name of agent: Patent attorney Haruaki Koebi and 2 others Figure 4

Claims (2)

[Claims] (1) A water supply means for supplying water into a tank, a first water level detection means for detecting the water level in the tank due to the water supply from the water supply means, and a set in the tank that circulates the water supplied by the water supply means. a second water level detection means provided at the bottom of the main body to detect overflow from the tank and water leakage inside the main body; an abnormality notification means for giving an alarm, and a control means for controlling the water supply means, washing means, and drainage means to perform a series of sequential operations of washing, rinsing, and drying according to a set order, and the control means is a second
A dishwasher characterized in that when a signal from the water level detection means is inputted, the abnormality notification means issues an abnormality notification and the draining means is operated for a certain period of time. (2) The control means inputs the signal from the second water level detection means, and if the abnormality notification state is already in place, the control means adjusts the water level at which the drainage means is operated based on the signal from the first water level detection means to a predetermined water level. Claim 1 characterized in that the water level is lower than
Dishwasher safe as stated.