JP5591615B2 - Hybrid type dryer and drying method, drying control method of dryer - Google Patents

Description

  The present invention relates to a hybrid dryer and drying method used for drying foods, tobacco, etc., and a drying control method for the hybrid dryer.

  Conventional dryers for general foods (agricultural products such as shiitake mushrooms and vegetables, marine products such as small fish) are equipped with multi-level shelves in the drying chamber, and dry trays (generally called “shrimp”) are arranged. Move to the room, hang on each shelf, close the door, then heat the air introduced into the hot air generator by the blower with the combustion heat of the burner to generate hot air, and send the generated hot air to the lower part of the drying chamber Then, it blows up from the lower tray to the upper tray to dry the dry matter on the tray. The hot air blown up from the tray becomes wet air and is discharged to the outside from the exhaust port or returned to the hot air generator from the circulation port.

  As a heat source for such a dryer, a burner that mainly uses petroleum-based fuels such as heavy oil is generally used (see Patent Document 1), but a small dryer using an electric heater as a heat source has also been proposed (patent). Documents 2 and 3) have been proposed.

Japanese Patent Laid-Open No. 11-173755 Registered Utility Model No. 3005693 Registered Utility Model No. 3059903

However, oil savings associated with recent rising oil prices and environmental policies (CO ₂ reduction) are widely demanded, and there is a limit to the control technology using only burners, and further fuel saving is becoming difficult. On the other hand, a dryer using the above-mentioned electric heater as a heat source generates hot air by itself, and therefore requires a large amount of electric power, and also requires a power facility for such a dryer, which uses a conventional burner. Was not suitable.

  Also, when the outside air temperature is low, such as in winter, the temperature rise speed in the drying chamber does not increase or the temperature cannot be raised to the set temperature, the area of the intake port is physically reduced to reduce the air volume and maintain the hot air blowing temperature. However, there is a problem that a delay in drying and a deterioration in quality due to a shortage of air flow occur and the user has difficulty in drying management.

The present invention has been made in view of the above problems, and provides a dryer and a drying method capable of saving fuel and reducing CO ₂ by combining a burner and a heater as a heat source of the dryer. An object of the present invention is to provide a drying control method capable of reducing the drying cost and improving the drying quality by combining the control of the burner and the control of the heater.

In order to solve the above problems, a dryer according to the present invention includes a hot air generator and a drying chamber, and includes a burner for generating hot air supplied into the drying chamber.
A heater capable of heating the air introduced into the hot air generator from the air inlet and / or the circulating air from the drying chamber together with the burner, or the circulating air from the drying chamber alone ;
Based on the drying temperature set in the drying program, the burner and heater are used in the initial stage of supplying only the introduced air to the drying chamber and in the middle of drying when the circulating air is mixed with the introduced air and supplied to the drying chamber. The most important feature is that a control means for operating only the heater is provided in the latter stage of drying in which only the circulating air is supplied to the drying chamber .

When generating hot air to be supplied to the drying chamber, a burner with a large amount of heat generation is used as the main heat source, and a heater is combined as an auxiliary heat source, and the circulating air with a large amount of retained heat from the drying chamber is used alone as an auxiliary heat source. By heating with, the fuel consumption of the burner can be reduced and CO ₂ can be reduced.

  The dryer according to the present invention has a second feature in that the heater is disposed in the hot air generator and above the furnace of the burner.

  The air introduced into the hot air generator from the air inlet and / or the circulating air from the drying chamber can be efficiently heated by the heater in the hot air generator.

According to a third feature of the dryer according to the present invention, the control unit performs ON / OFF control of each operation of the burner and the heater in accordance with a drying temperature set in the drying program and an indoor temperature sensor in the drying chamber. To do.

  Combining a burner with large amplitude of ON / OFF control (operation-stop-operation) with a heater with small amplitude of ON / OFF control (operation-stop-operation) makes drying control easy and is necessary for drying. At the same time as ensuring the amount of heat generated, the amount of heat generated can be reduced and the drying cost can be reduced. Since drying control becomes easy, the finish of drying is improved and the drying quality is improved.

A drying method according to the present invention includes a hot air generator and a drying chamber, and a drying method using a dryer including a burner for generating hot air to be supplied into the drying chamber.
The dryer is provided with a heater capable of heating the air introduced into the hot air generator from the air inlet and / or the circulating air from the drying chamber,
The drying process is divided into the initial drying stage, the middle drying stage, and the late drying stage.
In the initial stage of drying, where only the introduced air is supplied to the drying chamber, and in the middle stage of drying, where circulating air is mixed with the introduced air and then supplied to the drying chamber, drying is performed by using both a burner and a heater and supplying only circulating air to the drying chamber. The most important feature is that only the heater is used in the latter period.

In the early and middle drying stages when low or normal temperature outside air is introduced, a burner and a heater are used together to secure the amount of heat necessary to raise the temperature, and only circulating air with a large amount of retained heat is used without introducing outside air. In the latter stage of drying, by using only the heater, the fuel consumption of the burner can be saved and CO ₂ can be reduced.

  The drying method according to the present invention is characterized in that, in the drying process, the process after the process in which the ratio of circulating air is 60% or more is switched to heater heating.

In the drying process, after the process in which the ratio of the circulating air having a large amount of retained heat at a high temperature is increased, the fuel consumption of the burner can be reduced and the CO ₂ can be reduced by using only the heater.

A drying control method for a dryer according to the present invention includes a hot air generator and a drying chamber, and includes a burner and a heater for generating hot air to be supplied into the drying chamber, and a drying control of the dryer including a control unit that controls the operation thereof. A method,
Based on the set drying temperature in the drying program, the ON / OFF temperature of the burner in the low temperature side, respectively set the ON / OFF temperature of the heater to a high temperature side, provided the temperature difference between them Rutotomoni,
The burner and heater are used in combination with each ON / OFF temperature of the burner and heater in the initial stage of drying in which only the introduced air is supplied to the drying chamber and in the middle of drying in which circulating air is mixed with the introduced air and supplied to the drying chamber. In the latter stage of drying, when only circulating air is supplied to the drying chamber, set the temperature at which only the heater can be operated .
Based on the temperature difference and the signal from the indoor temperature sensor installed in the drying chamber, the control means performs each operation of the burner and the heater so that the indoor temperature of the drying chamber is maintained at the drying temperature set by the drying program. Independent ON / OFF control is the main feature.

By setting the ON / OFF temperature of the burner to the low temperature side and the ON / OFF temperature of the heater to the high temperature side based on the drying temperature set in the drying program and providing a temperature difference between them, for example, drying By adjusting the heater OFF temperature to the temperature setting value, the burner operation is stopped before reaching the drying temperature setting value, and thereafter the heater is controlled only to raise the temperature to the setting value. Consumption can be saved and CO ₂ can be reduced.

  In addition, by combining a burner with a large ON / OFF control operation width with a heater with a small ON / OFF control operation width, it is possible to secure the amount of heat generated for drying and at the same time reduce the amount of generated heat and reduce drying costs. . Furthermore, by setting the heater to the high temperature side in the ON / OFF control, it is possible to automatically switch the operation of the heater and the burner according to the ratio of the heat load necessary for drying, and when the circulation ratio increases It becomes easy to perform energy-saving control where only the heater is in operation and the burner is not operated.

  The drying control method for a dryer according to the present invention is characterized in that the temperature difference is set to 1.5 ° C to 2.5 ° C.

  By setting the temperature difference between 1.5 ° C and 2.5 ° C, the drop in the room temperature after the heater on the high temperature side is stopped is large in the initial drying stage and the middle drying stage when low or normal temperature outside air is introduced. The heater and the low-temperature side burner are operated alternately, but at the end of drying, where only high-temperature circulating air is supplied, the drop in the room temperature after the heater on the high-temperature side stops is small, so only the high-temperature side heater should be operated. Can reduce the fuel consumption of the burner.

  The drying control method for a dryer according to the present invention includes a signal from an outdoor temperature sensor installed outside the drying chamber at the initial stage of drying in which only the air introduced into the hot air generator from the air inlet is supplied to the drying chamber. When the outside temperature of the drying chamber is equal to or lower than the predetermined temperature, the control means operates the exhaust damper of the drying chamber in the closing direction to add the circulating air from the drying chamber to a part of the hot air supplied to the drying chamber. Is the third feature.

  Especially in the low temperature period such as the winter season, in the initial stage of drying in which only the low temperature outside air introduced from the air inlet is supplied to the drying chamber, a considerable amount of heat is required to raise the temperature to the set drying temperature. Necessary and the fuel consumption of the burner is large. By returning a part of the high-temperature circulating air to the hot air generator, the heat quantity of the high-temperature circulating air can be effectively used, and the fuel consumption of the burner can be reduced. The predetermined temperature is 5 ° C., for example.

As described above, according to the dryer according to the present invention, the heater is combined with the burner, the burner and the heater are used in combination at the initial stage of drying and the middle stage of drying, and the heater is operated only in the latter stage of drying. Compared to conventional dryers that rely on burner fuel combustion for all of these processes, fuel consumption of the burner can be reduced and CO ₂ can be reduced. Further, by combining a burner with a large operating width with a heater with a small operating width, drying control can be facilitated, and the amount of heat necessary for drying can be secured, and generation of excess heat can be suppressed and the drying cost can be reduced.

In addition, according to the drying method of the present invention, the initial stage of drying and the middle stage of drying, in which low temperature or normal temperature outside air is introduced, is used in combination with a burner and a heater, and the latter stage of drying using only high temperature circulating air is performed by using only the heater. Burner fuel consumption can be reduced and CO ₂ can be reduced.

Furthermore, according to the drying control method of the present invention, the fuel consumption of the burner can be reduced, the CO ₂ can be reduced, the drying control can be facilitated, and the drying quality can be improved.

Sectional drawing which shows 1st Embodiment and shows the dryer which concerns on this invention, The graph which shows the drying program of the dryer shown in FIG. 1, and the process of drying, (A) is an explanatory view showing the state of ON / OFF control at the initial stage of drying and the middle stage of drying in the dryer of the present invention, (B) is an explanatory view showing the state of ON / OFF control at the same time in the conventional dryer, (A) is explanatory drawing which shows the mode of ON / OFF control of the drying end in the dryer of this invention, (B) is explanatory drawing which shows the mode of ON / OFF control of the simultaneous period in the conventional dryer.

  An embodiment for carrying out the present invention will be described with reference to FIGS. In FIG. 1, 100 is a dryer.

  First, the structure of the dryer 100 will be described. As shown in FIG. 1, the dryer 1 includes a hot air generator 110 and a drying chamber 130.

  In the hot air generator 110, a furnace 113 having a burner 112 at the lower part of a casing 111, a heat exchanger 114 communicating with the furnace 113, and a blower 115 are arranged at the upper part. An electric heater 116 is disposed between the heat exchanger 114 and the blower 115 above the furnace 113. The electric heater 116 generates heat by electric power from an external power source (external power) (not shown). A control device 117 and a chimney 118 communicating with the heat exchanger 114 are arranged outside the hot air generator 110.

  The hot air generator 110 heats fresh outside air taken in from the air inlet 119 of the upper unit by the blower 115 by the burner 112 and the electric heater 116. That is, the burner 112 is heated by the furnace 113 heated by the combustion heat of the fuel (petroleum / gas system) and the heat exchanger 115 following the furnace 113, and the electric heater 116 is heated by the heat generated by the nichrome wire and dried. Hot air is sent from the lower hot air outlet 120 to the ventilation space (preheating chamber) of the side drying chamber 130.

  Note that an intake damper 121 for adjusting the amount of outside air is attached to the intake port 119. The opening degree of the intake damper 121 is controlled by a control signal from the control device 117.

  The drying chamber 130 is provided with a plurality of rows × multiple rows (for example, 15 rows) of shelves 132 inside a box-shaped casing 131, and in the illustrated example, a large number of drying trays are arranged on 2 rows × multiple rows of shelves 132. 133 can be accommodated. A rectifying plate 135 is provided at the lower portion of the casing 131 to form a large number of holes 135a while leaving the ventilation space 134 between the bottom inner surface. The rectifying plate 135 functions to rectify the hot air sent to the lower portion of the casing 131 and blow it up as a uniform flow into the drying chamber 130.

  An exhaust port 136 is opened in the upper ceiling of the casing 131, and an exhaust damper 137 is provided in the exhaust port 136. The exhaust damper 137 is opened and closed in conjunction with the movement of the intake damper 120. In the upper part of the side wall on the hot air generator 110 side, a circulation port 138 for returning the hot air blown up in the drying chamber 130 as circulating air into the hot air generator 110 is provided. The circulating air returned into the hot air generator 110 can be heated by the burner 112 and the electric heater 116.

  Near the hot air outlet 120, a dry bulb thermometer 122 that measures the indoor temperature (drying temperature) of the drying chamber 130 into which hot air dried from the hot air outlet 120 is blown is installed. In addition, a relative humidity detection sensor 123 that detects the relative humidity in the drying chamber 130 is installed in the drying chamber 130 above the third stage from the bottom of the drying tray 133.

  The controller 117 of the dryer 1 includes a drying temperature (° C.), a process time (hour), an air volume (%), an air supply / exhaust damper open as a drying program for each process in the initial stage of drying, the middle stage of drying, and the final stage of drying. A plurality of patterns are input and set in advance with the degree (%) as one combination.

  The burner 112 and the heater 116 are independently turned on / off according to a drying program in the controller 117 based on a signal from a dry bulb thermometer (indoor temperature sensor) 122 in the drying chamber 130 (two positions). Controlled). Based on the drying temperature set in the drying program, the ON / OFF temperature of the burner 112, that is, the ON (operation) temperature and the OFF (stop) temperature of the burner 112 are set to the low temperature side, the ON / OFF temperature of the heater 116, That is, the ON (operation) temperature and the OFF (stop) temperature of the heater 116 are set to the high temperature side, respectively, and a temperature difference ΔT is set between the two. 3A and 4A show ON / OFF control diagrams of the burner 112 and the heater 116. FIG. FIG. 3 (A) shows the initial drying stage and the middle drying stage, and FIG. 4 (A) shows the final drying stage.

  In this embodiment, the drying program in the control device 117 sets the OFF temperature of the heater 116 to the set value of the drying temperature, and the temperature difference ΔT between the heater 116 and the burner 112 is 1.5 ° C. to It is set to 2.5 ° C. The operation width of each ON / OFF control of the burner 112 and the heater 116 is set to 0.7 ° C to 1.0 ° C. Furthermore, the drying temperature is set so as to increase stepwise from the beginning of drying to the end of drying.

  Next, a drying method using the dryer 100 configured as described above and a drying control method of the dryer 100 will be described below with reference to FIGS. .

  As shown in FIG. 2, in the shiitake mushroom drying program, the drying process is performed at the initial stage of drying (first process / second process), middle stage of drying (third process, fourth process, fifth process), and final stage of drying (sixth process). ). And from the initial stage of drying to the end of drying, the drying temperature is 38 ° C. → 41 ° C. → 45 ° C. → 47 ° C. → 54 ° C. → 60 ° C., and the ratio of circulating air is 0% → 20% → 40% → 60% → 100%. And it is set to be higher step by step. The stroke time from the first stroke to the fifth stroke is set to 2 hours each, and the sixth stroke is set to 6 hours. The temperature difference ΔT between the burner 112 and the heater 116 is set to 2 ° C.

(Dry initial)
In accordance with the drying program, in the initial stage of drying (first stroke / second stroke), the intake port 119 and the exhaust port 136 are fully opened by the control signal from the control device 117, and the introduced outside air is exhausted in its entirety.

  The start operation of the control device 117 shown in FIG. 1 starts the operation of the burner 112 (combustion operation) and the operation of the heater 116 (heat generation). At the same time, by driving the blower 115, outside air is taken in from the intake port 119, dry hot air is generated by heating from the furnace 113 and the heat exchanger 114 by the operation of the burner 112, and heating by the operation of the heater 116, and the hot air outlet 120. Then, the air is fed into the lower ventilation space of the drying chamber 130, passes through the current plate 135, and blows up inside the drying chamber 130. Meanwhile, the water in the shiitake on the tray 133 is evaporated. The blown-up air is exhausted from the ceiling exhaust port 136 to the outside through an exhaust duct (not shown).

  Meanwhile, the relative humidity detection sensor 123 in the drying chamber 130 detects the relative humidity in the drying chamber 130, and sends a detection signal to the control device 117. As time passes, the relative humidity in the drying chamber 130 decreases in the same manner as the change in the weight of shiitake mushrooms in FIG. At the same time, on the basis of a signal from the dry bulb thermometer 122 in the drying chamber 130, each operation of the burner 112 and the heater 116 is independently ON / OFF controlled so as to maintain the set value of the drying temperature.

  FIG. 3A shows an ON / OFF control diagram of each operation of the burner 112 and the heater 116 in the initial stage of drying and in the middle stage of drying. In the first step, after the operation is started, the room temperature of the drying chamber 130 suddenly rises and approaches the drying temperature set value of 38 ° C., but the burner 112 is stopped by a signal from the dry bulb thermometer 122 at an intermediate temperature of 36 ° C. (OFF). When the room temperature reaches 38 ° C. due to preheating, the heater 116 is also stopped (OFF) by a signal from the dry bulb thermometer 122. When the room temperature passes the upper peak point and starts to decrease, the heater 116 is operated again (ON) at 37 ° C., and the burner 11 is also operated (ON) again at 35 ° C. during the decrease. As a result, the room temperature passes the lower peak point and starts to rise again, and this is repeated for the first step (2 hours). Here, in the first step, the ON / OFF temperature of the burner 112 is set to 35 ° C./36° C., and the ON / OFF temperature of the heater 116 is set to 37 ° C./38° C.

  When the first step is completed by the timer measurement, the setting value of the drying temperature is raised to 41 ° C. by the progress of the drying program. The room temperature rises due to the operation of the burner 112 and the heater 116 based on the control signal from the control device 117, but the burner 112 stops at 39 ° C. in the middle, and when the temperature reaches 41 ° C., the heater 116 also stops. When the room temperature passes the upper peak point and starts to drop, the heater 116 is operated again at 40 ° C. on the way, and the burner 112 is also operated again at 38 ° C. on the way. As a result, the room temperature passes the lower peak point and starts to rise again, and this is repeated for the second process time (2 hours). Here, in the second step, the ON / OFF temperature of the burner 112 is set to 38 ° C./39° C., and the ON / OFF temperature of the heater 116 is set to 40 ° C./41° C.

(Dry season)
In accordance with the drying program, the intake port 119 and the exhaust port 136 are partially closed during the middle of drying (the third stroke, the fourth stroke, and the fifth stroke). A part of the introduced outside air is exhausted, and a part thereof is returned to the hot air generator 110 as circulating air.

  When the second step is completed by the timer measurement, the set value of the drying temperature is raised to 45 ° C., the burner 112 stops at 43 ° C. while the room temperature rises, and the heater 116 also stops at 45 ° C. The heater 116 is operated again at 44 ° C. on the way from the upper peak point, and the burner 112 is also operated again at 42 ° C. on the way to the lower peak point. This is repeated during the third stroke. Here, in the third step, the ON / OFF temperature of the burner 112 is set to 42 ° C./43° C., and the ON / OFF temperature of the heater 116 is set to 44 ° C./45° C.

  When the third step is completed by the timer measurement, the set value of the drying temperature is raised to 47 ° C., the burner 112 is stopped at 45 ° C. while the room temperature is rising, the heater 116 is stopped at 47 ° C., and the temperature is being lowered. The heater 116 is operated again at 46 ° C., and the burner 112 is also operated again at 44 ° C. during the lowering, and this is repeated during the fourth stroke. Here, in the fourth step, the ON / OFF temperature of the burner 112 is set to 44 ° C./45° C., and the ON / OFF temperature of the heater 116 is set to 46 ° C./47° C.

  When the fourth step is completed by the timer measurement, the set value of the drying temperature is raised to 54 ° C., the burner 112 stops at 52 ° C. while the room temperature rises, and the heater 116 also stops at the set value of 54 ° C. The heater 116 is operated again at 53 ° C. while being lowered from the upper peak point, and the burner 112 is again activated at 51 ° C. while being further lowered, and this is repeated during the fifth stroke. Here, in the fifth step, the ON / OFF temperature of the burner 112 is set to 51 ° C./52° C., and the ON / OFF temperature of the heater 116 is set to 53 ° C./54° C.

  As shown in FIG. 3A, in the initial drying stage and the intermediate drying stage, the low temperature burner 112 and the high temperature heater 116 are alternately operated, and the fuel (heavy oil, kerosene, gas) of the burner 112 can be saved. In the case of operation with only the burner 112 as in a conventional dryer, as shown in FIG. 3 (B), the ON / OFF control two-position swing width (the swing width of the upper peak point and the lower peak point) is up and down. However, the combined use of the heater 123 makes it possible to reduce the fluctuation width and maintain the set value of the drying temperature. Moreover, energy utilization efficiency can be raised by this.

(End of drying)
At the end of drying (sixth step), the intake port 119 and the exhaust port 136 are fully closed, and the ratio of the circulating air is 100%.

    FIG. 4A shows an ON / OFF control diagram of each operation of the burner 112 and the heater 116 at the end of drying. When the fifth step is completed by the timer measurement, the setting value of the drying temperature is raised to 60 ° C. The burner 112 stops at 58 ° C. while the room temperature rises, and the heater 116 also stops at the set value of 60 ° C. At the end of drying, the heater 116 starts operating again at 59 ° C. on the way from the upper peak point, but immediately starts to rise from the lower peak point, stops again at 60 ° C., and thereafter in the sixth step. Only the ON / OFF control of the heater 116 is repeated. Here, in the sixth step, the ON / OFF temperature of the burner 112 is set to 57 ° C./58° C., and the ON / OFF temperature of the heater 116 is set to 59 ° C./60° C.

  At the end of drying, only high-temperature circulating air is supplied and no outside air is introduced. Therefore, a drop in the room temperature after the heater 116 is stopped is small. Therefore, it is easy to maintain the set value of the drying temperature. By setting the temperature difference in the control to 2 ° C., as shown in FIG. 4A, it is possible to operate only the heater 116 at the end of drying. For this reason, the fuel of the burner 112 can be saved.

  As described above, by operating the heater 116 in combination, the fuel of the burner 112 can be saved and the set value of the drying temperature in each drying process can be easily maintained. And dry quality can be improved.

  In the middle of drying, for example, the fifth and subsequent steps, in which circulating air accounts for 60% or more of the whole, may be switched to the operation of only the heater 116 by timer control until the end of drying (the operation of the burner 112 is stopped at the same time). ). When the circulating air is 60% or more of the whole, the introduced outside air is as low as 40% or less, and the heat capacity of the circulating air can be used as it is. Can be maintained. As a result, this also leads to fuel saving and energy saving operation of the burner 112.

  In the above embodiment, the operation of the heater 116 is ON / OFF controlled, but the heating capacity can be proportionally controlled by a thyristor, a triac (switching element), or the like.

  In addition, the hot air generator 110 of the present dryer 100 can be used not only for supplying hot air to the drying chamber 130 but also for hot air heaters for supplying hot air to the facility horticulture house. It is possible to apply a control method in which the burner 112 and the heater 116 are independently turned ON / OFF to the wind heater.

  2 using a conventional SP-30 type food dryer (specification: 30 pieces of shrimp type, processing capacity 150-200 kg, burner nozzle capacity 5.7 L / h, heat output 40,000 kcal / h) According to this, 200 kg of shiitake (Hiwako) was dried in winter, and the fuel oil (kerosene) consumption of the burner was measured, and the fuel consumption rate of each drying process was determined.

  The total fuel consumption of the burner is 27.22L, and the fuel consumption ratio is 33%, 29%, 25%, 13 if the total consumption is 100% from the beginning of drying to the end of drying as shown in FIG. It was found that the fuel consumption rate gradually decreased as the ratio of circulating air increased from 0% → 20% → 40% → 60% → 100%. In particular, in the case of the fifth and subsequent steps in the middle stage of drying (the ratio of circulating air was 60%), the fuel consumption ratio until the end of drying was only about 10%.

  From the above test results, there is almost no fuel consumption in the drying stage with a large amount of circulation, especially after the fifth step (the ratio of circulating air is 60%) in the middle stage of drying, and the electric heating capacity is 4,000 to 6,000 kcal / kw. It was found that if an electric heater of about .h (three-phase delta connection heater) was used, it could be dried sufficiently. As a result, by combining an electric heater having the above-mentioned electric heating capability with a conventional burner, it was possible to minimize the equipment cost, and to achieve appropriate drying control of shiitake mushroom and reduction of burner combustion consumption.

  In particular, if the temperature difference between the low-temperature side burner and the high-temperature side heater is set to 1.5 to 2.5 ° C, the initial stage of drying and the middle stage of drying will be alternate operation of the burner and heater, and the final stage of drying will be the operation of only the heater. Appropriate drying control of shiitake mushrooms and burner combustion consumption were reduced.

  The hybrid dryer and drying method according to the present invention can be used as a dryer and drying method for foods (such as shiitake mushrooms and marine products) and leaf tobacco. The drying control method according to the present invention can be used as a drying control method for the above. Furthermore, the present invention can also be applied to a facility horticulture heater.

DESCRIPTION OF SYMBOLS 100 Dryer 110 Hot-air generator 111,131 Casing 112 Burner 113 Furnace 114 Heat exchanger 115 Blower 116 Electric heater 117 Controller 118 Chimney 119 Inlet 120 Hot-air outlet 121 Intake damper 122 Dry bulb thermometer 123 Relative humidity detection sensor 130 Drying room 132 Shelf 133 Drying tray 134 Ventilation space 135 Rectifying plate 135a Hole 136 Exhaust port 137 Exhaust damper 138 Circulation port

Claims (8)

In a drier having a hot air generator and a drying chamber, and a burner for generating hot air to be supplied into the drying chamber,
A heater capable of heating the air introduced into the hot air generator from the air inlet and / or the circulating air from the drying chamber together with the burner, or the circulating air from the drying chamber alone ;
Based on the drying temperature set in the drying program, the burner and heater are used in the initial stage of supplying only the introduced air to the drying chamber and in the middle of drying when the circulating air is mixed with the introduced air and supplied to the drying chamber. And a drier having control means for operating only the heater in the latter stage of drying in which only circulating air is supplied to the drying chamber .   The dryer according to claim 1, wherein the heater is disposed in a hot air generator above the furnace of the burner. 3. The control unit according to claim 1, wherein the control unit performs ON / OFF control of each operation of the burner and the heater according to a drying temperature set in the drying program and an indoor temperature sensor in the drying chamber. 4. Dryer. In a drying method using a dryer equipped with a hot air generator and a drying chamber, and equipped with a burner for generating hot air supplied into the drying chamber,
The dryer is provided with a heater capable of heating the air introduced into the hot air generator from the air inlet and / or the circulating air from the drying chamber,
The drying process is divided into the initial drying stage, the middle drying stage, and the late drying stage.
In the initial stage of drying, where only the introduced air is supplied to the drying chamber, and in the middle stage of drying, where circulating air is mixed with the introduced air and then supplied to the drying chamber, drying is performed by using both a burner and a heater and supplying only circulating air to the drying chamber. A drying method characterized by using only a heater in the latter period.   The drying method according to claim 4, wherein, in the drying step, the step after the step in which the circulating air occupies 60% or more is switched to heater heating. A drying control method for a dryer, comprising a hot air generator and a drying chamber, comprising a burner and a heater for generating hot air to be supplied into the drying chamber, and a control means for controlling the operation of these,
Based on the set drying temperature in the drying program, the ON / OFF temperature of the burner in the low temperature side, respectively set the ON / OFF temperature of the heater to a high temperature side, provided the temperature difference between them Rutotomoni,
The burner and heater are used in combination with each ON / OFF temperature of the burner and heater in the initial stage of drying in which only the introduced air is supplied to the drying chamber and in the middle of drying in which circulating air is mixed with the introduced air and supplied to the drying chamber. In the latter stage of drying, when only circulating air is supplied to the drying chamber, set the temperature at which only the heater can be operated .
Based on the temperature difference and the signal from the indoor temperature sensor installed in the drying chamber, the control means performs each operation of the burner and the heater so that the indoor temperature of the drying chamber is maintained at the drying temperature set by the drying program. A drying control method, wherein ON / OFF control is independently performed.   The drying control method according to claim 6, wherein the temperature difference is set to 1.5 ° C. to 2.5 ° C.   In the initial stage of drying in which only the air introduced into the hot air generator from the air inlet is supplied to the drying chamber, the control is performed when the outdoor temperature of the drying chamber is equal to or lower than a predetermined temperature based on an outdoor temperature sensor installed outside the drying chamber. 7. The drying control method according to claim 6, wherein the means operates the exhaust damper of the drying chamber in the closing direction to add the circulating air from the drying chamber to a part of the hot air supplied to the drying chamber.

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