JPS59107138A - Electric water heater - Google Patents

Abstract

PURPOSE:To decrease the opening and closing frequency of a contact and to improve the durability of the contact by a method wherein a main heater circuit is maintained under an opening condition within a fixed range of a hot water temperature after the detection of a steam, in an electric water heater with a boiling detector. CONSTITUTION:A water is heated by electrifying of a main and an auxiliary heater 9, 10, when a water temperature rises nearly 90 deg.C, a returning thermostat switch 11 and a thermostat switch 12 of the auxiliary heater 10 are made OFF, the hot water temperature rises up 100 deg.C, the generation of a steam is started. A steam detecting thermostat switch 16 detects the generation of the steam, then the switch is made OFF. Thereby, a coil of a relay 16 is excited and the relay is made OFF, the boiling is stopped. Thereafter, the relay 16 is made self- holding and kept under opening condition even during the hot water temperature is lowered, when the temperature is lowered nearly 89 deg.C, the hot water temperature is maintained at nearly 90 deg.C by ON/OFF of the thermostat switch 12 fof the auxiliary heater 10. When the hot water temperature is lowered below 85 deg.C, the returning thermostat switch 11 is made ON, the relay 16 is closed. By such a structure, the durability of the contact can be lengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric water heater having boil detection means.

Conventional electric water heaters with a boiling function use a water temperature detection method that has a temperature sensor installed at the bottom of the container. There are one type and one type with a timer, but both have room temperature, water temperature, and water volume.

Variations in operation tend to occur due to voltage fluctuations, etc., and satisfactory performance cannot be achieved. In order to eliminate these drawbacks, there is still a type that extracts steam from boiling water in a container, uses a thermoswitch to detect the steam temperature, shuts off the heater, and keeps warm with a heat retention circuit. When the temperature of the water rises while keeping it warm, it will boil again, and the boil detection system will operate and shut off the heater again, repeating boiling and keeping warm. The disadvantage was that the contacts operated frequently, shortening the life of the contacts.

The present invention is equipped with a device for detecting boiling by steam.
f+, a steam water heater, which attempts to eliminate the above-mentioned drawbacks.

In the 11th unit 1, 1 is a container, 2 is an outer box, 3 is a stopper with a steam passage 4, 6 is formed above the container 1/a spout for hot water, and 6 covers the top of the stopper 3. The upper lid is connected to the outer box 2 at one end with a hinge or the like, and the other end is tightly attached to the upper part of the outer box 2 by a grapple device (not shown). γ is a handle attached to the outside of the outer box 2, 8 is a bottom stand, 9 is a main heater provided on the side of the container 1, 10 (l-1: auxiliary heater provided on the bottom of the container 1, 11 is a container 1 12 is a thermoswitch for controlling the auxiliary heater 10, and 13 is a heat insulating material for keeping the container 1 warm. 14C
1: Steam outlet provided in the upper lid 2, 15 is the steam outlet 14
This is a steam detection thermoswitch placed close to and facing the 16 is a relay, which has contacts 17 that are opened and closed by an excitation coil. Each part has a circuit as shown in Figure 2 or Figure 3.

Now, its operation will be explained based on the circuit shown in FIG. 2. When water is poured into the container 1 and the power is connected, the main heater 9 and the auxiliary heater 10 are energized and the water temperature rises. The state (
is shown in FIG. The solid line in FIG. 4 is a water temperature increase curve, and the dotted line is a temperature increase curve on the upper surface of the vapor detection thermoswitch 150 case. When the water temperature rises, the return thermoswitch 11 and the thermoswitch 12 of the auxiliary heater 10 are first turned off at around 90'C. Water temperature 100°
When the temperature reaches C, steam starts to come out, and the steam detection thermoswitch 15 detects this temperature and turns OFF. Ru・.

Then, the coil of relay 16 is energized and contacts 17 are opened. After that, the boiling stops and the water temperature gradually drops, but during this time the relay 16 continues to hold itself and the contacts 17 remain open. When the water temperature reaches approximately 89° C., the thermoswitch 12 of the auxiliary heater 10 is turned on, and the auxiliary heater 10 is energized to gradually raise the water temperature. 90°C
When it reaches this point, the circuit switch 12 is turned off again, and this operation is repeated from then on. During this time, the contacts 17 remain open and there is no repeated boiling as in the prior art. If cold water is added and the temperature drops below 85°C, the reset thermo switch 11
is in the ON state, and no current flows through the excitation coil of the relay 16, so the contact 17 closes.The contact of the steam detection thermoswitch 15 returns naturally in about 2 minutes, so... The water is in the initial state, boiling is performed only once, and then it is kept warm.

FIG. 3 performs a similar operation. That is, when the power is turned on, the coil of the relay 16 is energized and the contact 17 is closed, so that the main heater 9 and the auxiliary heater 10 are energized. Thereafter, thermoswitches 11, 12, and 15 are opened in the same order as described above. When the thermoswitch 15 is opened, no current flows through the coil of the relay 16, so the contacts 17 remain open. When the water cools down to 90°C, the thermoswitch 12 is closed, the auxiliary heater 10 is energized, and the above-mentioned heat-retaining state is repeated. If you add cold water to 85°C
When below, Boo 1 switch 11 closes and relay
The contact closes and becomes the /'' (starting state), and the operation is the same as described above.

As explained above, in the present invention, by the systematic operation of the relay and the thermoswitch for returning the thermosiver for steam detection, the temperature reaches the ideal temperature-retaining state after boiling only once and exhibiting the sterilization effect. It is something that solves the conventional problems.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the water heater of the present invention, Fig. 2 is its wiring diagram, Fig. 3 is another wiring diagram different from Fig. 2, and Fig. 4 is a water temperature It is a curve diagram showing the rising state of temperature and the temperature state of the upper surface of the case of the thermoswitch for vapor detection. 1... Container, 2... Outer box, 9...
・Main heater, 1o... Auxiliary heater, 11...
...Reset thermo switch, 12...Thermo switch, 14...Steam outlet, 16...
・Thermoswitch for steam detection, 16...Relay, 17...Contact.

Claims (3)

[Claims] (1) Main and auxiliary heaters, a steam outlet when boiling, a steam detection thermoswitch that is activated by the steam temperature from the steam outlet, and a device that detects boiling of water and shuts off the main heater circuit. , an auxiliary heater circuit that operates after the device is activated, and a main heater circuit that operates when the temperature of the hot water falls below the predetermined heat retention temperature? , an electric water heater equipped with a resetting device. (2) The device for restoring the main heater circuit connects a thermoswitch for steam detection and a normally closed contact of a relay in series,
The first range of the patent Nri is formed by connecting the excitation coil of the relay and the reset thermoswitch in parallel with this.
Electric water heater as described in section. (3) The device for restoring the main heater circuit consists of a thermoswitch for steam detection and a normally open contact of a relay connected in series.
The electric water heater according to claim 1, wherein a return thermoswitch is connected in parallel with this, and an excitation coil of a relay is connected in parallel with the main heater.