JPH0236088B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water heater such as a coffee maker used in a general household.

Conventional technology Conventionally, this type of water heater boils water in a water melter, senses the temperature of the water, opens a heating circuit, and then operates a lever to supply hot water. In the device,
If the water is not supplied immediately after it is boiled, the water temperature will drop and the components of coffee etc. will not be extracted sufficiently. As a result, the temperature of the finished coffee liquid was too low and the result was poor taste.

In order to improve this problem, conventionally, as shown in FIGS. 3 and 4, the water melter 1 is equipped with a heater 2, and a valve 4 is installed in the hot water supply port 3 located at the bottom of the water melter 1. It has been proposed that the valve 4 is opened and closed in conjunction with the movement of an elastic temperature sensing plate 5 shaped like a reversing spring.

Problems to be Solved by the Invention According to such a conventional configuration, the water put in the water dispenser 1 is heated by the heater 2, and when the water temperature reaches a predetermined temperature or higher, the valve 4 is operated, but the reversing spring is activated. is reversed to open the hot water supply port 3, and hot water automatically drips from the hot water supply port 3. However, since the heat-sensitive material is inside the water melter 1, the temperature distribution inside the water melter 1 is significantly different due to convection when the water is heated, resulting in variations in the operating time of the elastic temperature sensing plate 5, and an increase in the temperature of the water. Since the gradient of the elastic temperature sensing plate 5 was small, variations in the operating temperature of the elastic temperature sensing plate 5 itself greatly affected the operating time, resulting in poor sensing accuracy. Moreover, since the elastic temperature sensing plate 5 is located inside the water melter 1,
There was a problem that it deteriorated easily and its characteristics changed.

Furthermore, the opening/closing of the power supply circuit of the heating heater 2 and the valve 4
Since the valves are opened and closed separately, there was a risk that the heater 2 would be in a dry state, or that the heater 2 would be cut off and the valve 4 would not open while the water temperature was low. .

Means for Solving the Problem In order to solve this problem, the present invention provides a steam hole in the upper part of a closed water tank, a heating element and a hot water supply valve are attached to the water tank, and hot water is ejected from the steam hole. A steam detection element that detects steam, and a power cutoff switch that operates the hot water supply valve in conjunction with the operation of the steam detection element and simultaneously cuts off power supply to the heating element,
A steam hole cover is attached to the steam hole, which normally closes the steam hole and opens the steam hole when the steam pressure in the water tank reaches a certain level.

Function In the above configuration, the steam hole cover always closes the steam hole, and when it is heated by the heating element in the water tank and starts to boil, and the water tank reaches a certain vapor pressure or higher, the steam pressure increases to the closing force of the steam hole cover. The steam overcomes this and blows out vigorously, rapidly raising the temperature of the steam detection element, opening the hot water supply valve linked to the steam detection element, and starting hot water supply. At the same time, the vapor detection element is de-energized to the heating element that activated the cut-off switch. The steam hole cover then closes the steam hole in conjunction with the rapid depressurization inside the water tank, cutting off the ejection of steam. In this way, immediately after the water in the water tank boils, the steam detecting element is hit by steam and the temperature rises rapidly, and after sensing the temperature rise, the temperature begins to drop without being hit by unnecessary steam.

Examples Hereinafter, the first and second examples of the present invention will be described.
This will be explained with reference to the figures. In the figure, reference numeral 11 denotes a water tank having a D-cut circular heating element 12 at the bottom and a hot water supply valve 13 located at a distance from the heating element 12 at the D-cut. A water inlet 15 is formed above the water tank 11 by opening the substantially cylindrical wall 14 by curving inward at its upper end. A lid 16 is attached to the water inlet 15 to keep the water tank 11 in a sealed state.

Reference numeral 17 denotes a steam hole provided in the substantially cylindrical wall at 14, and is located above the heating element 12. This steam hole 1
7 has a bent portion 19 with a hole 18 formed therein.
is bent toward the outside of the water tank 11. Reference numeral 20 denotes a steam hole cover rotatably attached to the bent portion 19, which constantly closes the steam hole 17 with its own weight, and closes the steam hole 17 when the inside of the water tank 11 reaches a certain level of steam pressure. Open.

21 is a container having a container portion 22 and a support portion 23 on which the water tank 11 is attached. The support section 23 is connected to a base 25 having a columnar section 24, and a storage section 26 is provided between the container section 22 and the columnar section 24.
is formed.

The hot water supply valve 13 includes a valve stem 27 that can be raised and lowered, a valve body 28 attached to the valve stem 27, and a valve spring 2 that biases the valve stem 27.
9, and the valve body 28 is always urged in the closing direction by a valve spring 29. The valve stem 27 is the valve spring 29
When it operates against the biasing force and opens, the water tank 1
The water (hot water) in the cup 1 passes through the hot water supply pipe 30 and the hot water supply port 31 and drips into a cup 34 placed in the storage section 26 (on which a filter case 32 and a case lid 33 are placed).

A steam detection tube 35 is arranged in parallel with the steam hole 17 and protrudes above the support column 23, and is provided with an opening hole for steam. A sliding rod 36 is inserted into the steam detection tube 35 , and a steam detection element 37 is installed between the inner upper surface of the steam detection tube 35 and the upper flange portion of the sliding rod 36 . This vapor detection element 37 is made of a shape memory alloy made of Ti-Ni alloy or the like, and has been subjected to memory heat treatment to exhibit a spring effect at temperatures below 100°C.

38 is a watertight packing that watertightly blocks the steam detection tube 35 and the container 21, and contains the steam detection element 3 inside.
A return spring 39 is attached that acts to constantly compress the air conditioner 7.

Reference numeral 40 designates a valve lever, which forms a protruding piece 42 that opens a disconnection switch 41 that can cut off electricity to the heating element 12 when the sliding rod 36 is moved downward by the steam detection element 37. The lower end of the valve stem 27 has an upper surface that protrudes downward through the packing 44.
It is located at the lower end of the . Reference numeral 45 denotes a locking lever that is biased by a spring 46 disposed on the sliding rod 36 facing the valve lever 40 and locks the valve lever 40 in the state where the disconnection switch 41 is opened.

47 is a power switch, and 48 is a release switch for unlocking the operation of the valve lever 40.

Reference numeral 49 denotes a open contact, which is connected in series with the cut-off switch 41 and serves as a power supply circuit to the heating element 12. When the power switch 47 is up, it is not energized, and when the power switch 47 is down, it is not energized. Projecting piece 50
The normally open contact 49 is thereby closed and locked by a lever 52 biased by a spring 51.

The operation of an embodiment of the invention comprising a steam configuration will now be described. When the power switch 47 is pressed down, the normally open contact 49 is closed via the protruding piece 50 of the power switch 47, and electricity is started to be applied to the heating element 12, thereby starting to heat the water in the water tank 11. When the water in the water tank 11 rises and falls and begins to boil, and the steam pressure in the water tank 11 increases, push open the steam hole cover 20 and open the steam hole 17.
The steam is ejected more forcefully and instantly raises the temperature of the steam detection element 37 inside the steam detection tube 35. Steam detection element 3 whose temperature instantly rose above the operating temperature
7 immediately begins to stretch, overcomes the biasing force of the return spring 39, and pushes down the sliding rod 36. The sliding rod 36 pushes down the valve lever 40, and the protruding piece 42 opens the disconnection switch 41, cutting off the electricity to the heating element 12. At the same time as the valve lever 40 opens the disconnection switch 41,
The valve rod 27 is pushed up at the other end via the fulcrum 43 to open the hot water supply valve 13.

The boiling water in the water tank 11 passes through the hot water supply valve 13 and falls into a filter case 32 containing a paper filter and coffee powder to begin brewing coffee. When the power to the heating element 12 is cut off, the water tank 11
When the boiling of the water in the water tank 11 gradually stops and the steam pressure in the water tank 11 decreases to a certain value or less, the steam hole cover 20 closes the steam hole 17 by its own weight. As a result, the vapor detecting element 37 is no longer exposed to steam, so the temperature of the vapor detecting element 37 begins to fall.

Note that the steam hole 17 does not need to be placed in a part of the water tank 11; for example, the lid 16 may be placed so that the steam ejected from there hits the steam detection tube 35; The steam hole 17 may be arranged so that the steam hits the steam detection tube 35 through the steam hole 17.

Effects of the Invention As described above, in the present invention, the steam detection element is not exposed to steam while the steam pressure in the water tank is rising due to the opening/closing operation of the steam cover locked to the steam vent. There is no temperature rise, and when the vapor pressure exceeds a certain value, the steam jets out from the steam vents and evenly hits the vapor detection element, causing the temperature of the vapor detection element to rise with a large gradient.

Furthermore, when boiling ends and the vapor pressure falls below a certain value, the steam lid closes and the vapor no longer hits the vapor detection element, causing a temperature drop with a large gradient. Therefore, since the temperature rise gradient is large when the temperature of the vapor detection element passes through the operating motion when the temperature rises, the variation over time is small, and even if there is variation in the operating temperature of the vapor detection element for each product, the temperature increase gradient is large. The variation in operating time for each sensor is reduced, and sensing operation can be performed reliably and sensing accuracy can be improved.

In addition, because the temperature gradient is large when the temperature rises and when the temperature falls, the time for the vapor detection element to generate force is shortened, and since there is no local temperature variation, unevenness in the force generated by the element is reduced, which also improves durability. A big improvement can be made.

Furthermore, since the steam vents are always closed, the inside of the water tank can be kept clean and other benefits can be expected.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a water heater according to an embodiment of the present invention, FIG. 2 is a perspective view showing main parts of the same embodiment, and FIG. 3 is a sectional view showing a conventional water heater.
FIG. 4 is a sectional view showing the main parts. 11...Water tank, 12...Heating element, 13...
Hot water supply valve, 17...Steam hole, 20...Steam hole cover, 3
7... Steam detection element, 41... Power cutoff switch.

Claims (1)

[Scope of Claims] 1. A closed water tank having a steam hole in the upper part, a heating element for heating water in the water tank, a hot water valve capable of discharging water in the water tank, and a water supply valve capable of discharging water from the water tank from the steam hole. a steam detection element that detects ejected steam; a power cutoff switch that operates the hot water valve in conjunction with the operation of the steam detection element and simultaneously cuts off power supply to the heating element; A hot water supply device comprising a steam hole cover that can be opened and closed to close a steam hole and open the steam hole when the water tank reaches a certain steam pressure or higher.