JPS5825970B2 - Liquid temperature detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid temperature detection device that detects the average temperature of a liquid.

Conventionally, for example, a hot water temperature detecting device in a bathtub has a detecting device 10 submerged above the hot water as shown in FIG. It is now possible to

However, before the hot water in the bathtub is stirred, the temperature is not the same throughout, and the upper part is usually hotter than the lower part.

Therefore, in conventional systems, when the detection device is located at the top, it detects a high water temperature, so at the time the alarm is issued, the bottom of the water is still cold and its average temperature is lower than the specified temperature, resulting in a situation where the boiling method is insufficient. It is in.

On the other hand, if the detection device is located below the hot water, no alarm will be issued even when the average temperature of the hot water reaches an appropriate temperature, resulting in the problem of over-boiling the water.

The present invention has been made in view of this problem, and provides a detection device that can easily obtain a liquid at a predetermined temperature by detecting the average temperature of a liquid such as hot water.

The present invention will be described below with reference to the illustrated embodiments. 1 is a bathtub, 2 is a gas burner, and 3 is a temperature detection tube. As shown in FIG. It consists of a capillary member 5 called a wing that has a capillary action such as a mesh or sintered metal attached to the inner surface of the container, and a heat-sensitive element 6 such as a thermocouple inserted into the inside of the hollow container 4 from one end.

The capillary member 5 is previously impregnated with a working liquid such as water, alcohol, or fluorocarbon that causes evaporation or condensation.

Reference numeral 7 designates a support base mounted so that the temperature detection tube 3 can be moved in the vertical direction, 8 a water level detector fixed to the upper end of the temperature detection tube 3, and 9 an alarm activated by temperature and water level.

In the above structure, when filling the bathtub 1 with water,
The alarm 9 is set in advance to detect the water level, and at the same time, the support stand 7 is erected in the bathtub 1, and the temperature detection tube 3 is slid to adjust the position of the water level detector 8.

When water is supplied to the bathtub 1, the water level gradually rises, first immersing the temperature detection tube 3, and then reaching the water level detector 8, at which point a signal flows from the water level detector 8 to the alarm 9 to issue an alarm.

The next time you boil water, the temperature detection tube 3 is already in the water, so you just need to set the alarm 9 to detect the water temperature, and there is no need to move the detection part between water level detection and water temperature detection. can be omitted.

When the burner 2 is ignited, the temperature of the water in the bathtub 1 gradually rises, but a temperature gradient occurs in the depth direction such that the upper part is hot and the lower part is cold.

At this time, the temperature detection tube 3 operates as follows.

That is, in FIG. 3, if the hot water area is A and the cold water area is B, the working liquid impregnated in the capillary member 5 of the temperature detection tube 3 is warmed by the hot water in area A and absorbs the heat of vaporization from the hot water. Take away and evaporate.

This steam increases the steam pressure in this part, and the steam flows in the direction of lower steam pressure, that is, to region B as shown by the arrow in the figure.

Here, the steam is cooled and condensed, giving off heat of liquefaction.

The condensed liquid returns to area A by the capillary action of the capillary member 5 as indicated by the arrow in the figure.

When such circulation of the working liquid occurs, its vapor temperature Tv is expressed as follows.

Depth of area A IAs Water temperature T A N Depth of area B IB1 Water temperature TBN Temperature sensing tube 3 thermal resistance per unit length between hot water and working liquid vapor RAM, cold water and working liquid RBV is the thermal resistance per unit length of the temperature detection tube 3 between steam.
, if the amount of heat transferred from hot water to cold water by the temperature detection tube 3 is Q, then in equation (1), RA■ and RB in hot water.
Since V is almost equal, TV is expressed by equation (2).

From equation (2), it can be seen that the vapor temperature of the working liquid in the temperature detection tube 3 represents approximately the average temperature in the depth direction of the hot water inside the bathtub 1.

The temperature detection tube 3 detects the vapor temperature of this working liquid with a heat sensitive element 6, and when the detected temperature reaches a desired temperature, a signal is sent to the alarm device 9 to issue an alarm.

Therefore, at the time the alarm is activated, the water in the bathtub is at an appropriate temperature for bathing, and it is possible to prevent the bath from being under-boiled or over-boiled.

Note that since the temperature difference due to evaporation and condensation of the working liquid in the temperature sensing tube 3 is minute, the vapor of the working liquid and the wall surface temperature of the temperature sensing tube 3 are approximately the same temperature.

Therefore, in the embodiment shown in FIG. 3, the heat sensitive element 6 senses the vapor temperature of the working liquid, but the same effect can be obtained by sensing the wall temperature of the temperature detection tube 3. Of course.

By the way, although the present invention has been described above with reference to an embodiment for detecting the average temperature of hot water in a bathtub, it goes without saying that the present invention can also be used in other cases where it is desired to detect the average liquid temperature without stirring the liquid, such as in chemical experiments.

Since the present invention is configured as described above, it has the effect of easily obtaining a liquid at a predetermined temperature by detecting the average temperature of the liquid.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a conventional liquid temperature detection device, FIG. 2 is a cross-sectional view showing an embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view of a main part thereof. Note that the same reference numerals in the figures indicate the same or corresponding parts. 1 is a bathtub, 3 is a temperature detection tube, 4 is a hollow container, 5 is a capillary member, 6 is a heat-sensitive element, and 9 is an alarm. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A sealed rod-shaped hollow container, a capillary member provided on the inner surface of the hollow container and impregnated with a working liquid, a heat-sensitive element disposed in the hollow part of the hollow container, and a capillary member connected to the heat-sensitive element. A liquid temperature detection device characterized by being equipped with an alarm.