JPH019460Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Technical Field) The present invention relates to a heat exchanger used for heating water in drip coffee makers and the like. (Prior Art) Generally, a drip type coffee maker has a configuration as shown in FIG. In FIG. 1, 1 is a water storage tank, and water W in this water storage tank 1 passes through a pipe joint 2, passes through a check valve 3, and enters a water heating container 9. Heater installed in (not shown)
The water W in the water heating container 9 reaches a boiling state or a state just before boiling, and the internal pressure in the water heating container 9 increases. The water heating container 9
There is a force trying to get out. Here, since there is a check valve 3 on the water injection pipe 5 side, the water W flows in the direction A, but does not flow in the direction B, and the water in the water heating container 9 ( Hot water) W is discharged to the outside only from the hot water discharge pipe 6. When the water (hot water) W in the water heating container 9 is discharged as described above, the internal pressure of the water heating container 9 decreases,
The water W is poured into the water heating container 9 again by the water pressure of the water W in the water storage tank 1, and thereafter, the injection of water W into the water heating container 9 and its discharge to the outside are repeated intermittently. Water (hot water) intermittently discharged from the hot water discharge pipe 6
W is dripped into the filter part 7, passes through the coffee powder, and accumulates in the jug 8. Conventionally, in the above-mentioned drip type coffee maker, the coffee maker heating element consisting of the water heating container 9 and the heater is arranged parallel to each other, as shown in FIGS. 2a, 2b, and 2c, for example. It has a large number of running water guide holes 11, 11, .
A flat positive temperature coefficient thermistor heating element 13 is sandwiched between the sandwiching parts 12a and 12b of the porous tube 12 formed by forming a porous tube 2b.
The water supplied from the water supply pipe 14 attached to the tip of one of the holding parts 12a as shown by the arrow _A1 is supplied to the positive temperature coefficient thermistor heating element 1.
After passing through the main heat generating surface on the lower side of 3, it passes through the main heat generating surface on the upper side and exits from the drain pipe 15 attached to the tip of the other holding part 12b. It is generally known that a heat insulating plate 16 is disposed in the jug 8, and the coffee in the jug 8 is kept warm by the heat of the sandwiching part 12b. By the way, in the heating element for a coffee maker, the holding part 12b of the porous tube 12 having the water guide holes 11, 11, . The temperature of the heat insulating plate 16 will remain at the boiling point of water (100
(°C) or higher. For this reason, there was a drawback that the coffee in the jug 8 would cool down to about 75 degrees Celsius by the time coffee extraction was completed. In order to prevent the coffee in the jug 8 from getting cold when coffee extraction is completed, it is possible to provide a dedicated heater for the heat insulating plate 16, but this would complicate the structure of the coffee maker and increase costs. (Purpose of the invention) The present invention was made in view of the above circumstances, and its purpose is to connect water guide holes formed in a metal plate to a positive temperature coefficient thermistor that generates heat in a heat exchanger used in a drip coffee maker, etc. By forming it so that it runs near the center or side of the main heating surface of the body, the number of water guide holes interposed between the PTC thermistor heating element and the heat insulation plate placed on the metal plate can be reduced or eliminated. The object of the present invention is to obtain a heat exchanger capable of sufficiently keeping an object to be kept warm on a heat-insulating plate warm. (Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIGS. 3 and 4 show cross-sectional views of the heat exchanger according to the present invention, respectively. The heat exchanger shown in Fig. 3 is shown in Fig. 2a and Fig. 2b.
and the porous tube 1 of the heat exchanger shown in Figure 2c.
2, water guide holes 2 are provided on both sides in the width direction of the metal plate 21, which is made of a metal material with good thermal conductivity and is curved into a roughly U-shape and has a substantially constant width.
2, 22 and 23, 23 are formed. These water guide holes 22, 22 and 23, 23 are formed in both legs 21a of the metal plate 21 formed in a U-shape,
Positive temperature coefficient thermistor heating element 1 sandwiched between 21b
It is located near the side of the main heat generating surface of No. 3. When the heat exchanger shown in FIG. 3 is installed in the coffee maker shown in FIG. 2a, the positive temperature coefficient thermistor heating element 13
Water guide holes 22, 2 are provided between the and the heat insulating plate 16.
There are no water guide holes other than 2 and 23, 23, and therefore, the heat insulating plate 16 has water guide holes 22, 2
It is not affected by the boiling point of water in 2, 23, and 23, which is 100°C, and the temperature becomes high. That is, if the heat exchanger shown in FIG.
The heat insulating plate 16 is already maintained at a high temperature from the time when water is supplied into the jars 3 and 23 and coffee is extracted, and the coffee in the jug 8 can be kept at a high temperature, so that when the coffee extraction is completed, hot coffee is obtained. be able to. As shown in FIG. 4, instead of forming the water guide holes 22, 22 and 23, 23 on both sides of the metal plate 21, as described above, water guide holes 24, 24 are formed in the center of the metal plate 21'. These water guide holes 2
4 and 24 are formed into a U-shape.
It may be located at the center of the main heat generating surface of the PTC thermistor heating element 13 held between the legs 21'a and 21'b of the PTC thermistor 1'. Next, the temperature of the heat retention plate 16 and the coffee temperature when coffee is extracted by the coffee maker shown in FIG. 2a, the temperature of the heat retention plate 16 and the coffee temperature when coffee is extracted by the coffee maker using the heat exchanger shown in FIG. Heat retention plate 1 when brewing coffee by a coffee maker using the heat exchanger shown in Figure 4
When the temperature of No. 6 and the coffee temperature were measured, the results shown in the following table were obtained.

[Table] As can be seen from the above table, the coffee maker shown in Figure 2a has a coffee keeping temperature of 75°C, while the coffee maker using the heat exchanger shown in Figure 3 and the coffee maker shown in Figure 4 have a temperature of 75°C. In coffee makers using exchangers, the coffee temperature is 82℃, 83℃, and 7℃, respectively.
The temperature has increased by about 8 degrees Celsius. In the above embodiments, the PTC thermistor heating element 13 may be entirely covered with an exterior material, or
Both legs 21a, 21b, 2 of metal plates 21, 21'
It is possible to optionally add a member between 1'a, 21'b and the positive temperature coefficient thermistor heating element 13 to improve thermal coupling. Further, the present invention can be applied to various other electrical devices in addition to coffee makers. (Effects of the invention) As is clear from the above detailed description, the present invention provides a heat exchanger using a positive temperature coefficient thermistor heating element, in which the central part of the main heating surface of the flat positive temperature coefficient thermistor heating element is Alternatively, since the water guide hole is made to pass near the side, the number of water guide holes interposed between the PTC thermistor heating element and the heat insulating plate placed on the metal plate is reduced, and the object to be kept warm on the heat insulating plate is It is now possible to maintain sufficient heat,
Coffee after extraction can be kept at a sufficiently high temperature in a drip coffee maker or the like.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the principle of a drip coffee maker, Figure 2a is a cross-sectional view of the main parts of a conventional drip coffee maker, Figure 2b is a perspective view of the heat exchanger of the drip coffee maker shown in Figure 2a, Figure 2c is the second
3 and 4 are cross-sectional views of two embodiments of the heat exchanger according to the present invention, respectively. 11... Water guide hole, 12... Porous tube (12
a, 12b... sandwiching part), 13... positive temperature coefficient thermistor heating element, 14... water supply pipe, 15... drainage pipe, 16... heat insulation plate, 21, 21'...
...Metal plate, 21a, 21b, 21'a, 21'b...
...Legs, 22, 23, 24... Water guide holes.

Claims (1)

[Scope of utility model registration request] It consists of a roughly U-shaped metal plate with a plurality of water guide holes formed inside that run almost parallel to each other. A flat positive temperature coefficient thermistor heating element with both main surfaces as heating surfaces is sandwiched,
The water flowing through the water guide hole is heated by receiving heat from the two main heat generating surfaces, and is sent to a container located on a heat insulating plate placed on the upper leg of the two legs. A heat exchanger characterized in that the water guide holes are unevenly formed so as to run near the center or side of the main heat generating surface of the positive temperature coefficient thermistor heating element.