JP2859560B2 - Temperature controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a plant
The present invention relates to a temperature control device used to maintain the temperature in a greenhouse for growing crops such as fruits at a predetermined value.

[0002]

2. Description of the Related Art It is well known that a thermostat using a bimetal switch is incorporated as a temperature control device used to maintain the temperature in a greenhouse at a predetermined value for plant appreciation or the like. Such a temperature control device intermittently stops power supply to a heater installed in a greenhouse,
The room temperature is kept near the set temperature.

[0003]

However, in the conventional temperature control device, the room temperature fluctuates greatly above and below the set temperature even in a steady state, so that the temperature of the plant or crop may vary considerably from the appropriate growth temperature. There is a problem in that it hinders the growth of the cultivator and supplies excessive electric power to the heater, resulting in a large power consumption.

[0004] In order to solve such a problem, it is conceivable that the wall surface of the greenhouse is made of a heat insulating material so that the heat release to the outside of the greenhouse is minimized and the vertical amplitude of the room is reduced as much as possible. The problem is that wood is relatively expensive, which adds to the cost of growing it, and that insulation is generally low in light transmission, preventing plants and crops from being exposed to sunlight and hindering their growth. There is. In addition, the use of thermal insulation does not alter the nature of the air, which has a low thermal conductivity, and generally remains until the temperature control device, which is generally installed away from the heater, operates at the set temperature. Requires considerable time.

The present invention has been made in view of such a conventional problem, and has as its object to use a special material for a wall portion of a greenhouse without using a special material until the temperature control device operates. As well as reducing the vertical amplitude of the room temperature in the steady state significantly, keeping the plants and crops at an appropriate temperature at all times, and aiming for good growth of the plants and crops. An object of the present invention is to provide a temperature control device capable of preventing power supply and greatly reducing power consumption.

[0006]

In order to achieve the above object, a temperature control apparatus according to the present invention includes a thermostat using a bimetal switch inside a housing, and an operation lamp including a heating resistor and a light emitting diode. A thermo-accelerator circuit that is connected in series and a circuit that electrically connects the output outlet, a temperature control knob is disposed on a panel of the housing, and the output outlet and the thermo-accelerator circuit are connected to each other. It is electrically connected in parallel, and the heating resistor is arranged near the bimetal switch.

[0007]

[Function] When the bimetal switch is in the closed state,
Electric power is supplied to the heater through the output outlet, and current also flows through the heating resistor to generate Joule heat, which promotes the temperature rise of the bimetal switch located near the heating resistor. .

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a temperature control device according to an embodiment of the present invention. Temperature control device 1 of the present invention
As shown in FIGS. 1 to 4, a circuit in which a thermostat 3, a thermoaccelerator circuit 4, and an output outlet 9 are electrically connected inside a casing 2 having an appropriate shape such as a box.

[0009] As shown in FIG.
A temperature control knob 5 is fixedly attached to one end of a knob shaft 5c, and a temperature control knob 5 is provided on the front panel 2a. A temperature scale 6 is stamped on the front panel 2a around the knob body 5b. An operation lamp 4c that is turned on when the heater 12 is operated is disposed at an appropriate position on the front panel 2a. As shown in FIG. 2, a power cord 8 to which an AC power plug 7 is connected is led out from the rear panel 2b, and an output outlet 9 into which a power plug (not shown) for the heater 12 is inserted is fixed to the rear panel 2b. Are formed in the rear panel 2b.
Are provided at appropriate positions.

In the housing 2, as shown in FIGS. 3 and 4, one terminal of the power cord 8 is directly connected to one terminal of the output outlet 9, and the other terminal of the power cord 8 is connected via the thermostat 3. An electric circuit is formed in which the thermoaccelerator circuit 4 is connected in parallel with the output outlet 9 while being connected to the other terminal of the output outlet 9.

The thermostat 3 is, as shown in FIG.
When the temperature is lower than the set temperature, the bimetal switch 3a is used.
When the two metal plates come into contact with each other and come into a closed state and become conductive, and when the temperature is equal to or higher than the set temperature, the two metal plates separate and become open and become non-conductive. When the knob main body 5b is rotated, the contact member 5d connected to the other end of the knob shaft 5c presses one of the metal plates to change the gap between the two metal plates. Can be set to an appropriate temperature.

As shown in FIGS. 4 and 5, a thermoaccelerator circuit 4 includes a heating resistor 4a and a rectifying diode 4a.
b, an operation lamp 4c is mounted on a single board by electrically connecting them in series, and this board and the thermostat 3 are connected to a bimetal switch 3a by a heating resistor 4a, as shown in FIG. They are connected so that they are close to each other. still,
The operation lamp 4c is a light emitting diode (LED), and is turned on when a current flows through the thermoaccelerator circuit 4,
Indicates that power is being supplied to the heater.

When the temperature is lower than the set temperature, since the bimetal switch 3a is in the closed state, current flows to the heater 12 via the output outlet 9 and also flows to the thermoaccelerator circuit 4. Therefore, the heating resistor 4
a, Joule heat is generated, and the Joule heat is generated by the bimetal switch 3a disposed near the heating resistor 4a.
, And the operation of the bimetal switch 3a is sharpened.

Next, a case where temperature control is performed using the temperature control device 1 of the present invention will be described in comparison with a case where a conventional temperature control device is used.

[Experimental Examples 1 to 3] A glass box 11 having a width (w) of 800 mm, a height (t) of 1500 mm and a depth (d) of 450 mm as shown in FIG. 20 downward from the ceiling plate 11a of the box 11
The heater 12 was suspended at a position of 0 mm, and the heater 12 was placed substantially at the center of the bottom plate 11b. Here, the thermostat 3 of the temperature controller 1 used was US-410FX0F manufactured by Yokogawa Electric Corporation, and the heater 12 used was a heater with a radiator plate. A position near the front panel 2a of the temperature controller 1 and 20 mm from the front plate 11c is set as a measurement point A, and a position on the bottom plate 11b and 200 mm from the heater 12 is set as a measurement point B. Set. Thermocouple is M made by Yokogawa Electric Corporation
ODEL2459-03, TYPE-K was used.

Table 1 summarizes the resistance value of the heating resistor 4a, the distance between the heating resistor 4a and the bimetal switch 3a, the initial temperature in the greenhouse, and the temperature set in the greenhouse by the temperature controller 1 in each experimental example. Was.

[0017]

[Table 1]

The start and end of the conduction to the thermoaccelerator circuit 4, that is, the start and end of the operation of the heater 12, are detected, and at the measurement points A and B, every five minutes, and to the thermoaccelerator circuit 4. The temperature was measured at the start and end of each conduction. The results corresponding to Experimental Examples 1 to 3 are shown in FIGS. In these figures, hatched rectangles indicate that the heater 12 is in an operating state, black circles indicate the temperature at the measurement point A, and white circles indicate the temperature at the measurement point B.

FIGS. 8 and 9 show experimental examples 1 and 2.
As shown in the figure, the overshoot during the transient response is as small as about 2 to 3 ° C., the rise time is fast, the steady state is achieved in about 20 minutes, the transient characteristics are good, and the steady state deviation is also 1 ° C.
It can be seen that the steady state characteristics are extremely good. It can also be seen that in the steady state, the bimetal switch 3a repeatedly opens and closes in a very short time, and finely adjusts the power supply to the heater 12 to prevent excessive power supply. Regarding Experimental Example 3, as shown in FIG. 10, the transient characteristics and the steady-state characteristics are inferior to the results of Experimental Examples 1 and 2, but the rise time is fast and a steady state is reached in about 20 minutes, and the steady-state deviation is also about 2 ° C. It can be seen that the temperature was small and sufficient temperature control was performed.

[Comparative Example] The same box body 11 as in Experimental Examples 1 to 3
Was used as a greenhouse, a conventional temperature controller having no heating resistor 4a was hung at the same position, and the heater 12 was placed.
Further, thermocouples were set at the same measurement points A and B as in Experimental Examples 1 to 3. Table 1 also shows the initial temperature in the greenhouse and the temperature set in the greenhouse by the temperature control device in Comparative Examples along with Experimental Examples 1 to 3.

The start and end of the operation of the heater 12 are detected, and at the measurement points A and B, every five minutes,
Further, the temperature was measured each time the operation of the heater 12 was started and ended. The results are shown in FIG. 11. In this figure, similarly, the hatched rectangle indicates that the heater 12 is in the operating state, the black circle indicates the temperature at the measurement point A, and the white circle indicates the temperature at the measurement point B. ing.

As shown in FIG. 11, the amount of overshoot during the transient response is as large as about 8 ° C., the rise time is also slow, it takes about 30 minutes to reach the peak, the transient characteristics are poor, and The steady-state deviation is as large as about 8 ° C., cannot be maintained near the set temperature of 20 ° C., and it can be seen that the steady-state characteristics are greatly problematic. Further, the time interval in which the bimetal switch 3a is opened and closed in a steady state is long, and the heater 1
It can also be seen that excess power is being supplied to 2.

[0023]

According to the temperature control device of the present invention, the temperature rise of the bimetal switch is promoted by the Joule heat generated in the heating resistor. The vertical amplitude of the temperature is also greatly reduced, so that plants and crops can always be kept at a proper growth temperature.

Further, in the steady state, the bimetal switch repeatedly opens and closes in a very short time, and finely adjusts the power supply to the heater. Therefore, the power consumption can be greatly reduced without supplying excessive power to the heater. Can be reduced.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a temperature control device of the present invention as viewed from the front.

FIG. 2 is an external perspective view of the same upside-down state as viewed from a rear surface.

FIG. 3 is a transverse sectional view of the same.

FIG. 4 is a circuit configuration diagram of the same.

5A is a perspective view and FIG. 5B is a front view of a circuit board provided with a thermoaccelerator circuit.

FIG. 6 is an external perspective view of a connection state of a circuit board provided with a thermostat and a thermoaccelerator circuit.

FIG. 7 is an explanatory diagram showing the shape and dimensions of a greenhouse used in the experiment and the installation state of a heater, a temperature controller, and a thermocouple.

FIG. 8 is a diagram showing an operating state of a heater and a temperature change in a greenhouse in an experimental example in which temperature is controlled by the temperature control device of the present invention.

FIG. 9 is a diagram showing an operation state of a heater and a temperature change in a greenhouse in another experimental example in which the temperature is controlled by the temperature control device of the present invention.

FIG. 10 is a diagram illustrating an operation state of a heater and a temperature change in a greenhouse in another experimental example in which temperature control is performed by the temperature control device of the present invention.

FIG. 11 is a diagram illustrating an operation state of a heater and a temperature change in a greenhouse in a comparative example in which temperature control is performed by a conventional temperature control device.

[Explanation of symbols]

 Reference Signs List 1 temperature control device 3a bimetal switch 4a heating resistor 9 output outlet

Claims (1)

(57) [Claims] A thermostat using a bimetal switch inside a housing, a thermoaccelerator circuit formed by electrically connecting an operating lamp including a heating resistor and a light emitting diode in series, and an output outlet are electrically connected. Configure the connected circuit, arrange the temperature control knob on the panel of the housing,
The temperature control device, wherein the output outlet and the thermoaccelerator circuit are electrically connected in parallel, and the heating resistor is arranged near the bimetal switch.