JP2002034355A - Hot air heater for greenhouse for protected horticulture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot air heater for a greenhouse for protected horticulture, hardly having the fear of the hot air temperature from a blower becoming lower than a set temperature after stopping the combustion of a burner regardless of the largeness of the load of the greenhouse. SOLUTION: The blowing operation of the blower is continued for a prescribed time after stopping the burner at a heat exchanger part based on the off command of heating, and when the temperature of the blown air from the blower is lowered in comparison with the set temperature, the blowing operation is stopped or gradually reduced regardless of the set time in the hot air type heater having an heat exchanger part and capable of sending out the hot air to the interior of the greenhouse by the blower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-air heater for heating the interior of a greenhouse for cultivating crops (hereinafter simply referred to as a house) with hot air, and more particularly to heat exchange. The present invention relates to a hot-air heater provided with an air blower and for sending hot air into a house.

[0002]

2. Description of the Related Art Normally, in this type of hot air heater, a burner in a heat exchange section is turned on / off by information from a temperature sensor installed in the house, thereby controlling the temperature in the house to a set temperature (management). Temperature). That is, as shown in the operation state diagram illustrating the temperature transition in the heat exchange unit in FIG. 3, when the heating ON command is issued or when the temperature in the house is lower than the set temperature, the burner combustion in the heat exchange unit is performed. Start and steady operation at the set temperature (operation in which the temperature balance between the burner combustion and the blower is in an equilibrium state)
Is maintained. Then, when the heating off command is issued or the temperature in the house becomes higher than the set temperature,
Immediately after the combustion of the burner is stopped, blowing is continued from the blower for a predetermined time (time indicated by S in FIG. 3 = usually about 6 minutes) to cool the heat exchange unit, and after the predetermined time has elapsed, the blower is stopped. Then, the heat exchanging section is brought into the normal temperature state which is the same as the temperature in the house. By repeating such an operation, the temperature in the house is maintained at the set temperature.

However, this type of hot air heater is designed on the basis of a large load (during the operation indicated by the solid line (A) in FIG. 3). In the case of use or in the case where the load is relatively small such as in the early spring or early autumn (during the operation indicated by the broken line (B) in FIG. 3), the cooling time of the heat exchange unit may be shorter than in the case where the load is large. Nevertheless, the time of air blowing (cold air operation) becomes longer, so that the crop near the air outlet of the blower may have a growth failure, and special arrangement of the ventilation hole to avoid the growth obstacle. Was sometimes needed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem. After stopping the combustion of the burner, the temperature of the blown air from the blower is reduced regardless of the house load. The aim is to provide a hot-air heater for greenhouses that are not likely to be below the set temperature.

[0005]

Means for Solving the Problems The first aspect of the present invention, which achieves the above object, is a hot air heater for a horticultural house, which is provided with a heat exchanging section and uses a blower to send hot air into the house. In the heater, when the blower operation of the blower is continued for a predetermined time even after the burner of the heat exchange unit is stopped based on a heating-off command, and the blower temperature of the blower is lower than a set temperature. Is characterized in that the blowing operation of the blower is stopped regardless of the set time. Further, the warm air heater for a horticultural house according to the second invention of the present invention, while stopping the burner of the heat exchange unit based on a heating-off command, continues the air blowing operation in the air blower for a predetermined time, and When the blowing temperature becomes lower than the set temperature, the blowing amount in the blower is gradually reduced regardless of the set time.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the flowchart shown in the drawings.
The present invention is not limited to the embodiment.
Further, although the specific structure of the burner, the blower, and the like in the heat exchange section constituting the hot air heater is not particularly shown, the description is omitted because it is basically the same as the conventional product. Also, components such as a burner and a blower that are turned on and off according to time and temperature are controlled by a sequence control using a relay or a computer as in the conventional products.

[0007] When the heating is specified or when the temperature in the house is lower than the set temperature, the temperature sensor installed in the house issues a burner combustion and blower operation command in the heat exchange section, and the burner combustion is performed. Is started simultaneously with the start of operation, and the temperature in the heat exchange section rises to the preset temperature as shown in FIG. The steady operation at the set temperature (operation in which the temperature balance between the burner combustion and the blower is in an equilibrium state) is maintained until a heating-off command is issued. Then, when a heating-off command is issued or the temperature in the house becomes higher than the set temperature, the combustion of the burner is immediately stopped, and the temperature of the heat exchange section starts to decrease from the state shown in FIG. become.

At this time, in order to forcibly cool the heat exchanging section, as shown in the cooling flow chart of the heat exchanging section shown in FIG. Operation is performed for a predetermined time (Fig. 3
In step (2), the temperature indicated by "S" is normally continued for about 5 to 10 minutes (step 2), and the temperature of the blown air discharged from the blower is detected by the temperature sensor provided at the blower of the hot air heater for the facility gardening house. The blast temperature T to the blast setting temperature t
To avoid overcooling.

That is, in step 3, the blow time of the blower is compared with the blow time set time S. If the blow time of the blower has exceeded the blow time set time S, the process proceeds to step 4 to immediately stop the blow operation of the blower. At least, the cooling operation of the heat exchange unit is stopped (step 5). If the blow time of the blower has not exceeded the set time S, the process proceeds to step 6 where the blower temperature T discharged from the blower is set.
And the air setting temperature t are compared. As a result, the blast temperature T
If the air temperature is higher than the air setting temperature t, the process returns to step 3. If the air temperature T is lower than the air setting temperature t, the process proceeds to step 7, and the air blowing of the air blower is performed regardless of the set time S of the air blowing operation. The operation is immediately stopped to stop the cooling operation of the heat exchange unit. Such an on / off operation of the blower is repeated for a set time S (see FIG. 2).

In the above description (first invention), the blower operation by the blower is controlled to be on / off. However, when the blower temperature of the blower becomes lower than the set temperature, the blower set time is set. Irrespective of the above, the amount of air blown by the blower may be gradually reduced (second invention).

[0011]

As described above, the warm air heater for a horticultural house according to the present invention is provided with a heat exchanging section, in which a hot air is blown out into the house by a blower. The blower operation of the blower is continued for a predetermined time even after the burner of the heat exchange section is stopped based on the blower temperature, and if the blower temperature of the blower becomes lower than the set temperature, the blower in the blower regardless of the set time is blown. Since the operation is stopped or the amount of air is gradually reduced, there is no fear that the temperature of the air blown from the air blower falls below the set temperature after the combustion of the burner is stopped. This can be maintained irrespective of the magnitude of the house load, so that the crop near the blower vent may have a growth failure, or a special arrangement of the blower outlet to avoid the growth failure. There is no need to devise.

[Brief description of the drawings]

FIG. 1 is a cooling flow chart of a heat exchange section showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating an on / off operation of a blower.

FIG. 3 is an operation state diagram illustrating temperature transition in a heat exchange unit.

Claims (2)

[Claims] 1. A hot-air heater provided with a heat-exchanging section and for sending hot air into a house by a blower, wherein the blower in the blower is operated even after the burner of the heat-exchanging section is stopped based on a heating-off command. The facility horticulture is characterized in that the operation is continued for a predetermined time, and when the blower temperature of the blower becomes lower than a set temperature, the blower operation in the blower is stopped regardless of the set time. Hot air heater for house. 2. A hot-air heater provided with a heat-exchanging section and for sending warm air into a house by a blower, wherein the blower in the blower is stopped even after the burner of the heat-exchanging section is stopped based on a heating-off command. A facility wherein the operation is continued for a predetermined time, and when the blower temperature of the blower becomes lower than a set temperature, the blower volume in the blower is gradually reduced regardless of the set time. Hot air heater for gardening house.