JPS626480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dryer that dries objects to be dried using hot air.

Conventionally, in a dryer that stores clothes in a rotating drum and dries the clothes while rotating the drum, outside air drawn in by a fan is heated and hot-aired by a nichrome wire heater, and then heated and aired inside the rotating drum. The hot air was used to remove the moisture contained in the clothes, but the amount of air blown by the fan was set to 2 kg of the weight of the items to be dried to prevent red heat from the nichrome wire heater, and the heater capacity was In the case of 1.2kw, the air flow rate was set at about 1.6 to ^2.5m3 per minute. However, in such a conventional structure, the temperature of the hot air that comes into contact with the clothes and is actually inside the drum is relatively low at about 30°C, and therefore the total amount of moisture that can be removed from the clothes by the hot air is small, and the exhaust gas At the same time, the amount of heat discharged tends to be relatively large, the drying efficiency is low, the drying time is long, and the power consumption is very high.

The present invention has been made in view of the above circumstances, and its purpose is to reduce the amount of ventilation air by using a ventilation fan to exhaust humid air from a drying room and at the same time draw in the same amount of outside air into the drying room. By setting the air flow rate to a low level of ^1m3 per minute or less per 1kw of heater heat output, drying efficiency can be significantly improved, power consumption can be significantly reduced, and items to be dried can be dried in a short time. A dryer capable of further shortening drying time by configuring a fan to be rotated in the forward direction when the electric heater is activated, and reversely rotated when the electric heater is not in operation at the end of drying so that the amount of air blown is greater than when the fan is rotated in the forward direction. is to provide.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 1.
This will be explained with reference to FIG. 1 is an outer box with open front and rear sides, and the open back side of this box has many external air intake ports 2.
is removably closed by a back plate 3 formed with a
Further, the opening is removably closed by a front plate 5 in which a door receiving recess 4 is formed. and,
A door 6 is provided in the door receiving recess 4 so as to be openable and closable, and a short cylindrical clothing opening 7 is formed that extends from the door receiving recess 4 into the outer box 1. 8 is a rotating drum with a drying chamber 8a inside;
This is formed by a cylindrical wall 9, a rear end plate 10, and a front end plate 11, and the cylindrical wall 9 is formed with a plurality of buttfuls 12 protruding inward to scoop up dry matter and stir it by falling. has been done. Further, in the center area of the front end plate 11, a clothing opening 7 is provided.
An opening 13 communicating with the opening 13 is formed, and a rotation receiving part 14 formed at the periphery of the opening 13 in the forming process is fitted and supported on the outer periphery of the cylindrical clothing opening 7 via a well-known bearing member 15. There is. On the other hand, a bulging wall portion 16 that bulges inward is formed in a portion of the rear end plate 10 facing the opening 13, and a circumferential area near the outer periphery of this bulging wall portion 16 is a cylindrical wall. 9
An inclined annular portion 17 that diagonally faces the inner circumferential surface of the
A large number of ventilation holes 17a are formed in this inclined annular portion 17, and a large number of ventilation holes 16a are also formed in the central region of the bulging wall portion 16.
Reference numeral 18 denotes an auxiliary casing in the shape of a circular shallow container for forming a fan chamber 19 with the bulging wall portion 16. The auxiliary casing 18 is in the shape of a circular shallow container for forming the fan chamber 19 with the bulging wall portion 16. It is connected to the support plate 21 via the connecting member 18a so as to be in a fitted state. As shown in FIG. 2, both ends of the support plate 21 are connected to the opening edge of the rear opening 2 of the outer box 1 at the middle portion thereof by screwing means. One end of a rotating shaft 22 is rotatably supported in a cantilevered state by a shaft support member 23 in the middle part of the support plate 21, and the other end of the rotating shaft 22 extends horizontally to connect to the intake hole of the auxiliary casing 18. It passes through the opening 24 which also serves as the center of the bulging wall portion 16, which is the center of rotation of the rotating drum 8, and is connected to this portion by a connecting member 25 so as to rotate together with the rotating drum 8. A rotation center portion of a circulation fan 26 located in the fan chamber 19 is rotatably supported on the rotation shaft 22, and a driven pulley 27 that rotates substantially integrally with the circulation fan 26 is attached to the rotation shaft 22. It is located outside the chamber 19 and rotatably supported by the rotating shaft 22 . In the fan chamber 19, an electric heater 2 made of a nichrome wire heater is installed around the space in which the circulation fan 26 is disposed.
8 is placed. 29 is a motor, and a second pulley 32 is attached to one end of a motor shaft 29a via a first pulley 30 and a connecting member 31. A flat belt 33 is placed between the first pulley 30 and the outer periphery of the cylindrical wall 9 of the rotating drum 8, and a V-belt 34 is placed between the second pulley 32 and the driven pulley 27. . 35 is a tension pulley mechanism that applies tension to the flat belt 33. Reference numeral 36 denotes a sirot-shaped ventilation fan connected to the other end of the motor shaft 29a, which is connected to the end plate 3.
A plurality of arcuate blades 36b are attached to the outer circumference of the blade 6a, and as shown in FIG. The ventilation fan 36
The air flow rate when rotated in the forward direction is set to 0.8m ³ /min. The ventilation fan 36 is disposed in a fan casing 39 that communicates with an inlet duct 37 formed at the front lower part of the outer box 1 through an inlet 38, and is attached to a side wall of the fan casing 39. The formed discharge port 40 communicates with the outside of the outer box 1 via an approximately horizontally arranged exhaust duct 41 and an external exhaust port 42 formed at the end of the exhaust duct 41 . A circular protrusion 44 that protrudes into the clothing opening 7 is formed on the inner plate 43 of the door 6, and an internal exhaust passage 45 is formed between the outer periphery of the protrusion 44 and the inner peripheral surface of the clothing opening 7. . Reference numeral 46 denotes an air guide path that communicates with the internal exhaust path 45 via a filter 47, which is not shown in the figure, but is connected to the internal exhaust path 4.
5 is connected to the suction duct 37. 48 is a timer device attached to the front plate 5;
As shown in FIG. 4, this has a timer motor 48a and cam switches 48b and 48c. The timer device 48, electric heater 28, motor 29, etc. are connected as shown in the electric circuit diagram of FIG. Therefore, in this FIG. 4, 49 is the door 6.
A door switch that opens and closes in conjunction with the opening and closing of the door, 50
51 is a thermoswitch that is turned on when the exhaust temperature from the rotating drum 8 exceeds a predetermined temperature; 51 is a thermoprotector that is turned off when the electric heater 28 is abnormally heated; 52A and 52B are switches that are opened and closed in conjunction; When the switches 52A and 52B are turned on, the electric heater 28 generates heat of 1.2 kW and the motor 29 rotates at high speed, and when the switches 52A and 52B are turned off, the electric heater 28
A reactor 29a is connected in series to the motor 29, and the motor 29 is rotated at a low speed. 53 is a relay coil 53a and relay switches 53b, 53
54 is a capacitor.

Next, the operation of this embodiment configured as above will be explained. When the door 6 is opened and damp clothes to be dried are stored in the rotary drum 8, the door 6 is closed, the switches 52A and 52B are turned on, and the timer device 48 is set. Cam switches 48a and 48b are the fifth
The switching state is made as shown in the time chart shown in the figure, the motor 29 is rotated forward at high speed, and the electric heater 28 is energized (time T ₁ ). Then, the motor 29 rotates the rotating drum 8 and the circulation fan 26.
At the same time, the ventilation fans 36 are rotated in the forward direction, and the electric heater 28 is brought into a heat generating state with a heat output of 1.2 kW. When the rotating drum 8 is rotated,
The clothes inside are scooped up by the baffle 12 and are agitated by falling action. At the same time, the air in the drying chamber 8a is sucked into the fan chamber 19 by the action of the circulation fan 26 through the ventilation hole 16a located approximately in the center as shown by arrow c, and is heated by the electric heater 28. From the ventilation hole 17a to the cylindrical inner side surface of the drying chamber 8a as shown by the arrow d, that is, the cylindrical wall 9 of the rotating drum 8.
Circulating air that is blown out near the inside and circulating within the drying chamber 8a is generated, and the circulating air is constantly reheated by the electric heater 28. In this case, the amount of air blown by the circulation fan 26 is set so as not to cause the electric heater 28 made of a nichrome wire heater to become red-hot, that is, the amount of air blown is set to be sufficiently large compared to the amount of air blown by the ventilation fan 36 which rotates in the forward direction. Therefore, the amount of air blown by the ventilation fan 36 is 0.8 m ³ /
Since the air volume is set at a relatively low air volume of min, the air inside the rotating drum 8 rises at a high rate of temperature rise, as shown in the temperature characteristic curve in Figure 6, where the vertical axis represents temperature and the horizontal axis represents time. However, once the air temperature inside the rotating drum 8 reaches approximately 40° C., the air temperature becomes constant and the drying of the clothes progresses. Then, at the end of the drying process, the amount of moisture contained in the clothes decreases and the amount of moisture evaporated from the clothes decreases significantly, causing the temperature inside the rotating drum 8 to rise rapidly. When the temperature inside the rotating drum 8 suddenly rises in this way, the temperature of the exhaust gas from the rotating drum 8 also rises rapidly, so the thermo switch 50 is turned on (time T ₂ ), and the relay coil 53a of the relay 53 is turned on.
is energized. Then, relay switch 53
b is turned on, the timer motor 48a is operated, and the contact piece c-a of the cam switch 48c is turned off, and the contact piece c-
b is turned on, thereby causing the motor 29 to rotate in the reverse direction. At the same time, the relay switch 53c is turned off, the electric heater 28 is cut off, and the relay switch 53d is turned on, so that the relay coil 53a is self-held. Since the motor 29 is rotated in the opposite direction, the ventilation fan 36 is rotated in the opposite direction, thereby increasing the amount of air blown, and the rotating drum 8 and the circulation fan 26 are also rotated in the opposite direction. In this way, the electric heater 28
Since the inside of the rotating drum 8 is ventilated with a large amount of air by the ventilation fan 36 while the power is cut off, the temperature inside the rotating drum 8 rapidly decreases, and the clothes inside the rotating drum 8 absorb their own heat and moisture. and are released at the same time. When the operation in this state is continued for a predetermined period of time, the cam switch 48 is activated based on the timing operation of the timer device 48.
b and 48c are both turned off (time T ₃ ), thereby ending the drying operation.

Now, the present inventor has conducted various experiments and studies in order to improve the efficiency of the dryer, which will be described below. First, when drying items such as clothes, the rotating drum 8 shown in FIG.
In the temperature characteristic curve, when the temperature inside the rotating drum 8 changes from a constant state to a rapid temperature rise at the end of drying, it is 80 to 90 from the start of drying to the end of drying.
%, and therefore, based on this, the time is shown in Figure 6.
The time point indicated by T ₄ can be regarded as the end of drying, and it can be regarded that a drying time of m minutes is required at a constant temperature t° C. as shown by the dotted line in FIG. 6.

Here, Q: amount of air passing through the rotating drum 8 (m ³ /min), T: drying time (min), ρt: specific gravity of air at t°C (Kg/m ³ ), xt: amount of exhaust gas at t°C. Assuming that the absolute humidity (Kg/Kg'), x _t0 : the absolute humidity of the intake air at t ₀ ℃ (Kg/Kg'), and ω _n : the amount of moisture lost until the end of drying (Kg), Q×T× ρ _t ×(x _t −x _t0 )=ω _n …………(1), and i _t : enthalpy of exhaust gas at t°C (kcal/
Kg), i _t0 : enthalpy of intake air at t ₀ °C (kcal/
Kg), ρw: heater input (kw), η: thermal efficiency, then Q×T× _ρt ×(i _t −i _t0 =860/60×Pw×η×T
.........(2) Therefore, equation (1) represents the amount of moisture carried away by the exhaust gas, that is, the amount of water lost until drying, and equation (2) represents the amount of energy carried away by the exhaust gas, that is, the amount of electricity until the end of drying. Represents the amount of input energy to the heater. If the exhaust temperature t°C, air amount Q, heater input Pw, etc. are given to these equations (1) and (2), the drying time T can be calculated, and the heater input
The performance of the dryer is determined from the relationship between Pw and drying time T.

For example, if the weight of the clothes is 2 kg and the electric heater input is 1.2 kW, the relative humidity of the exhaust air can be adjusted to 60%, 70%, or 80% by changing the degree of agitation of the clothes and the amount of circulating air in the rotating drum. The above is a case where the air amount Q passing through the rotating drum is varied while being set to a constant value of %.
When the results obtained using equations (1) and (2) are graphed with the drying time T on the vertical axis and the air amount Q on the horizontal axis, if the intake air is 20°C and the humidity is 65%, Figure 7 shows If the intake air is 5℃ and the humidity is 65%, the 8th
It will look like the figure. It was also confirmed through experiments that these graphical results matched well with the actual situation. Therefore, it is clear from FIGS. 7 and 8 that if the humidity of the exhaust air is constant, the drying time can be shortened by decreasing the air amount Q, and the power consumption can be reduced accordingly. It is also clear that if the humidity of the exhaust air can be increased, the drying time can be shortened, and when the intake air temperature is low, increasing the humidity of the exhaust air is very effective in shortening the drying time. I can understand. In addition, when the degree of agitation of clothes and the amount of circulating air are kept constant, the amount of air Q is 0.2 per 1kw of heater input.
Experimentally, when decreasing m ³ /min, the humidity in the exhaust air tends to increase by about 5%, and this tendency is also clear from Figures 6 and 7, which is also consistent with the experimental results. It agrees well with the calculation results.

By the way, from Fig. 7 and Fig. 8 above, it has been found that it is better to reduce the air amount Q in order to shorten the drying time. Since it is inefficient to set them individually in practical use, based on Figures 6 and 7, we set the unit power and unit drying time T' per unit power and unit weight, assuming a heater input of 1 kW and a clothing weight of 1 kg. The drying time is plotted on the vertical axis.
Take T′ (min・kw/Kg) and plot (Q′m ³ /
min・kw), and taking into account changes in exhaust volume and exhaust air humidity, the intake air temperature is 20℃,
If the humidity is 65%, the result will be as shown in Figure 9, and if the intake air temperature is 5°C and the humidity is 65%, the result will be as shown in Figure 10.

Heater input based on these figures 9 and 10
Air amount per heater input Pw for dryers with different Pw and capacity of drying material (weight of clothes)
The drying time T' can be determined simply by determining Q'.

The results shown in FIGS. 9 and 10 also agree well with the experimental results in an actual dryer. That is, as an example, in a conventional structure in which the air amount Q is 1.8 m ³ , the weight of clothing is 2 kg, and the heater input Pw is 1.2 kw, the air amount Q' per unit heater input is 1.8/1.
2 = 1.5 (m ³ /min・kw), and if we put this on the horizontal axis of Figure 8, we can read the result T' = 49.2min・kw/Kg from the vertical axis, and the actual heater input Pw When the weight of clothes is included, the drying time T = 49.2 x 2.0/1.2 = 82 (min). The experimental drying time in a dryer with a conventional structure was 80 to 85 minutes, which agrees well with the above calculation formula.

In addition, if the air amount Q is set to 0.8 m ³ and the heater input is set to 1.2 kw as in this example, then the following equation is obtained: Q' = 0.8/1.2 = 0.67 (m ³ /min・kw )in,
From Figure 8, T' = 41.8 (min・kw/Kg), and therefore the drying time T = 41.8 x 2.0/1.2 = 70 (min). The experimental drying time for the dryer of this example is 65 to 70 minutes, which also matches the above calculation formula well, and moreover, the dryer of this example is compared to a dryer with a conventional structure. As a result, drying time is sufficiently shortened.

Now, if we consider the characteristic diagrams in Figures 9 and 10, we will see that in the characteristic diagram in Figure 9, the air amount Q' is 0.9.
In the same characteristic diagram, the slope of the characteristic curve changes with the boundary at m ³ /min・Kg, and there is an inflection point P _1. Therefore, if the air amount Q' increases beyond the inflection point P ₁ , drying will occur. If the rate of increase in time T′ is large and the air amount Q′ decreases below the inflection point P ₁ , the drying time
The rate of decrease in T' tends to be small, and the characteristic diagram in Figure 10 shows that the air amount Q' is 1.0 m ³ /min・Kg.
There is an inflection point P ₂ at the boundary, which has the same tendency as described above. That is, based on the trends shown in FIGS. 9 and 10, the air amount Q' should be at least 1.0.
By setting the drying time to less than m ³ /min・Kg, not only can the drying time be significantly shortened, but also the rate of change in the drying time T' will be small compared to the variation in the amount of air Q' when the product is manufactured. You can understand that it is easy to design and manufacture.

In this embodiment, the electric heater 2 is based on the results of various experiments and studies by the inventor.
The heat generation value of 8 is set to 1.2kw, and the air volume Q, which is the air flow rate of the ventilation fan 36, is set to 0.8m ³ /min, and as mentioned above, the air volume Q' is 0.67m ³ /min・kw.
As a result, good results were obtained with a drying time T of 70 minutes, which is shorter than that of a conventional structure with a drying time T of 82 minutes when dried under the same conditions. It can save 12 minutes,
Since the heater power consumption is reduced corresponding to the shortened drying time, the overall drying efficiency is greatly improved.

By the way, the amount of air flowing inside the rotating drum 8 Q
In the conventional structure, the electric heater 28 becomes red hot and the dryer becomes locally overheated, making it difficult to put it into practical use.However, in this embodiment, the red heat of the electric heater 28 can be prevented. Since the electric heater 28 is arranged around the outer periphery of the circulation fan 26 which has a sufficient amount of air to blow, the dryer can be easily put into practical use without causing local overheating.

In addition, when the ventilation fan 36 is operated, the bearing member 15
If a portion of the outside air is drawn into the ventilation fan 36 from the gap between the rotary receiving part 14 or the sealing member disposed between the door 6 and the door receiving recess 4, the ventilation The amount of air blown by the ventilation fan 36 may be set to be larger than the air amount Q flowing through the rotating drum 8 by an amount equivalent to the intruding outside air. Although the ventilation fan 36 is operated during the entire drying operation, for example, the ventilation fan 36 may be operated intermittently during the entire drying operation or a part of the drying operation by a motor other than the motor 29. In this case, the amount of air passing through the rotary drum 8, when averaged over the entire period during the drying operation, may be within the above-mentioned set air amount range.

Now, in this embodiment, the ventilation fan 36 is set so that the amount of air blown increases when it is reversely rotated at time _T2 , but the clothes in the rotating drum 8 are in a high temperature state at this time _T2 . Because of this, it has a considerable ability to evaporate moisture using its own thermal energy. Therefore, as in this embodiment, when the air flow rate of the ventilation fan 36 is increased after the electric heater 28 is turned off, the air inside the rotating drum 8 that has been deprived of moisture is quickly exhausted, and the outside air with less humidity is replaced. The thermal energy of the clothing itself can be used to promote the evaporation of moisture and to quickly cool the clothing, which is effective in shortening the total time required to dry the clothing.

FIGS. 11 to 14 show other embodiments of the present invention, and only the parts different from the above-described embodiments will be explained. That is, the electric heater 28 is removed from the above-described embodiment, the diameter of the opening 24 is reduced so that air cannot be taken in through the opening 24, and a substantially rectangular intake hole 55 is formed in the auxiliary casing 18. In this configuration, four PTC heaters 58, which are semiconductor heaters having positive temperature characteristics and sandwiched between electrode plates 56 and 57, are disposed in an air intake hole 55 via an insulating material 59. Then,
Since the PTC heater 58 has a positive temperature characteristic, it does not exhibit an overheating state like a nichrome wire heater, and the relationship between the airflow amount q and the input power p for one PTC heater 58 is shown in FIG. It has such characteristics. That is, when the air amount Q passing through the intake hole 55 is 0.8 m ³ /min, one PTC
The amount of ventilation q passing through the heater 58 is 0.2 m ³ /min, and the amount of heat generated per PTC heater 58 is
The total output of 4 units is 1.5kw at 375W. With this configuration, the amount of air blown by the circulation fan 26 does not have to be as large as in the above-mentioned embodiment using the nichrome wire heater, and can be set arbitrarily. The fan 26 may be provided as necessary.

As is clear from the above description, the present invention significantly improves drying efficiency because the amount of air passed through the drying room by the ventilation fan is set to a low air flow of 1 m ³ per minute or less per 1 kW of heater heat output. As a result, power consumption can be drastically reduced, and items to be dried can be dried in a short time.Furthermore, the ventilation fan can be reversed when the electric heater is not operating, so that the amount of air blown is larger than when the electric heater is operating. Therefore, it is possible to provide a dryer that can further shorten the drying time.

[Brief explanation of the drawing]

Figures 1 to 10 show one embodiment of the present invention, with Figure 1 being a longitudinal sectional view, Figure 2 being a rear view, Figure 3 being an enlarged side view of a ventilation fan, and Figure 4 being an enlarged side view of the ventilation fan. 5 is an electric circuit diagram, FIG. 5 is a time chart, FIGS. 6 to 10 are characteristic diagrams for explaining the operation, and FIGS. 11 to 14 show other embodiments of the present invention. Figure 11 is a longitudinal sectional view of the main part,
Figure 2 is a side view of the PTC heater section seen from the direction of arrow Y in Figure 11, and Figure 13 is a - side view of the PTC heater part in Figure 12.
A cross-sectional view along the line, FIG. 14, is a characteristic diagram of the PTC heater. In the drawing, 8 is a rotating drum, 8a is a drying chamber, 26
is a circulation fan, 28 is an electric heater, 29 is a motor, 36 is a ventilation fan, 48 is a timer device, 5
0 is a thermo switch, and 58 is a PTC heater (semiconductor heater, electric heater).

Claims (1)

[Scope of Claims] 1. A device in which an object to be dried stored in a drying chamber is dried with hot air from an electric heater, in which humid air is discharged from the drying chamber and at the same time the same amount of outside air is introduced into the drying chamber. A dryer characterized in that a ventilation fan is provided for drawing air into the room, and the ventilation air volume of the drying room by the ventilation fan is set to 1 m ³ per minute or less per 1 kW of heater heat output. 2. The dryer according to claim 1, further comprising a circulation fan that circulates air within the drying chamber. 3. The dryer according to claim 2, characterized in that an electric heater is disposed on the outer periphery of the circulation fan. 4. The dryer according to claim 1, characterized in that a semiconductor heater having positive temperature characteristics is provided as the electric heater. 5. In a drying chamber in which the items to be dried are dried by hot air from an electric heater, a ventilation system that exhausts humid air from the drying chamber and simultaneously draws the same amount of outside air into the drying chamber. A fan is provided, and the ventilation fan is rotated in the forward direction when the electric heater is activated, and the ventilation air volume of the drying room is set to a small air flow of 1 m ³ per minute or less per 1 kW of heater heat output, and the ventilation fan is rotated in the forward direction when the electric heater is activated. A dryer characterized by rotating in reverse when not in operation to increase the amount of air blown than when rotating forward.