U.S. patent application number 16/063210 was filed with the patent office on 2018-12-27 for clothes dryer.
The applicant listed for this patent is AQUA CO., LTD, QINGDAO HAIER WASHING MACHINE CO., LTD.. Invention is credited to Taichi HAYASHIDA, Jungo KATSUKI, Taiki MORI, Shinichi YOSHIMURA.
Application Number | 20180371683 16/063210 |
Document ID | / |
Family ID | 59055719 |
Filed Date | 2018-12-27 |
United States Patent
Application |
20180371683 |
Kind Code |
A1 |
KATSUKI; Jungo ; et
al. |
December 27, 2018 |
CLOTHES DRYER
Abstract
Provided is a clothes dryer, and the clothes dryer includes a
drum, an air supply and exhaust unit for supplying and discharging
the air for drying to and from the drum, a burner for heating the
air for drying, a temperature sensor for detecting the exhaust
temperature, and a heating control unit for performing a
temperature adjustment processing. The temperature adjustment
processing enables the burner to stop when the exhaust temperature
reaches an upper limit temperature and enables the burner to
re-operate when the exhaust temperature is lowered to a specified
re-ignition temperature. The heating control unit is provided with
a re-ignition temperature adjustment part that performs an
adjustment to lower the re-ignition temperature, and the
re-ignition temperature is gradually lowered through the
re-ignition temperature adjustment part every time when the
temperature adjustment processing is repeated and intermittently to
perform the re-ignition.
Inventors: |
KATSUKI; Jungo; (Tokyo,
JP) ; HAYASHIDA; Taichi; (Tokyo, JP) ; MORI;
Taiki; (Tokyo, JP) ; YOSHIMURA; Shinichi;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QINGDAO HAIER WASHING MACHINE CO., LTD.
AQUA CO., LTD |
Qingdao, Shandong
Chiyoda-ku, Tokyo |
|
CN
JP |
|
|
Family ID: |
59055719 |
Appl. No.: |
16/063210 |
Filed: |
December 16, 2016 |
PCT Filed: |
December 16, 2016 |
PCT NO: |
PCT/CN2016/110375 |
371 Date: |
June 15, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F 58/263 20130101;
D06F 2103/38 20200201; D06F 58/02 20130101; D06F 2105/28 20200201;
D06F 58/38 20200201; D06F 2105/20 20200201; D06F 58/30 20200201;
D06F 2103/08 20200201; D06F 58/26 20130101; D06F 2103/32 20200201;
D06F 2212/02 20130101 |
International
Class: |
D06F 58/26 20060101
D06F058/26; D06F 58/28 20060101 D06F058/28 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2015 |
JP |
2015-244788 |
Claims
1. A clothes dryer, comprising: a drum capable of accommodating
clothes, an air supply and exhaust unit for supplying and
discharging air for drying to and from the drum, a heating unit for
heating the air for drying supplied to the drum, an exhaust
temperature detection unit for detecting the temperature of the air
for drying that is discharged from the drum, and a heating control
unit for performing a temperature adjustment processing as follows:
stopping the heating unit when an exhaust temperature detected by
the exhaust temperature detection unit reaches a predetermined
upper limit temperature, and re-operating the heating unit to
perform a re-ignition when the exhaust temperature drops to a
predetermined re-ignition temperature, wherein the heating control
unit is provided with a re-ignition temperature adjustment part
that performs an adjustment to lower the re-ignition temperature,
and the re-ignition temperature is gradually lowered through the
re-ignition temperature adjustment part every time when the
temperature adjustment processing is repeated intermittently to
perform the re-ignition.
2. The clothes dryer according to claim 1, wherein the re-ignition
temperature adjustment part lowers the re-ignition temperature in
stages by a predetermined temperature to determine a new
re-ignition temperature every time when the temperature adjustment
processing is performed.
3. The clothes dryer according to claim 2, wherein the re-ignition
temperature adjustment part pre-sets a lower limit value for the
re-ignition temperature, and when the temperature adjustment
processing is repeated to enable the re-ignition temperature to
reach the lower limit value, the re-ignition temperature adjustment
part keeps the re-ignition temperature at the lower limit value,
and the heating control unit performs the re-ignition at the
re-ignition temperature thereafter.
4. The clothes dryer according to claim 2, wherein the re-ignition
temperature adjustment part acquires an elapsed time from the
re-ignition until the exhaust temperature reaches a predetermined
upper limit temperature, and adds a correction value to the
predetermined temperature based on the elapsed time.
5. The clothes dryer according to claim 1, wherein the heating unit
is a non-adjustable burner having no thermal power adjustment
function.
6. The clothes dryer according to claim 3, wherein the re-ignition
temperature adjustment part acquires an elapsed time from the
re-ignition until the exhaust temperature reaches a predetermined
upper limit temperature, and adds a correction value to the
predetermined temperature based on the elapsed time.
7. The clothes dryer according to claim 2, wherein the heating unit
is a non-adjustable burner having no thermal power adjustment
function.
8. The clothes dryer according to claim 3, wherein the heating unit
is a non-adjustable burner having no thermal power adjustment
function.
9. The clothes dryer according to claim 4, wherein the heating unit
is a non-adjustable burner having no thermal power adjustment
function.
10. The clothes dryer according to claim 6, wherein the heating
unit is a non-adjustable burner having no thermal power adjustment
function.
Description
TECHNICAL FIELD
[0001] The present invention relates to a clothes dryer capable of
reducing damages to clothes by lowering a temperature of the
clothes during overdrying regardless of the type and the amount of
the clothes.
BACKGROUND
[0002] Conventionally, a clothes dryer is known in which air for
drying heated by a burner is blown into a drum into which clothes
to be dried is introduced by a fan, and an exhaust is performed
from a back side of a main body (see, for example, Patent Document
1).
[0003] FIG. 5 is a flowchart showing a processing procedure in
which a conventional clothes dryer carries out a drying operation.
Regarding the clothes dryer disclosed in Patent Document 1, the
control unit generally is configured to perform a processing shown
in FIG. 5, and when a start button is pressed, the operation is
started and proceeds to step T1.
[0004] <Step T1>
[0005] In step T1, the control unit starts rotations of the drum
and the fan. As a result, a supply and exhaust of the air for
drying to and from the drum is started.
[0006] <Step T2>
[0007] In step T2, the control unit ignites the burner. As a
result, a supply of high-temperature air for drying to the drum is
started.
[0008] <Step T3>
[0009] In step T3, the control unit starts counting operation
time.
[0010] <Step T4>
[0011] In step T4, the control unit determines whether or not the
operation time has reached the end time and determines whether or
not to end the operation. When it is determined that the operation
is to be terminated, the process proceeds to step T10, and when it
is determined not to end the operation, the process proceeds to
step T5.
[0012] <Step T5>
[0013] In step T5, the control unit determines whether or not the
exhaust temperature has reached an upper limit temperature. When it
is determined that the exhaust temperature has reached the upper
limit temperature, the process proceeds to step T6, and when it is
not determined that the exhaust temperature has reached the upper
limit temperature, the process returns to step T4.
[0014] <Step T6>
[0015] In step T6, the control unit stops the burner. As a result,
air for drying of a substantially normal temperature which is not
heated is supplied into the drum, and the temperature inside the
drum is lowered.
[0016] <Step T7>
[0017] In step T7, the control unit determines whether or not the
operation time has reached the end time, and determines whether or
not to end the operation. When it is determined that the operation
is to be ended, the process proceeds to step T10, and when it is
determined not to end the operation, the process proceeds to step
T8.
[0018] <Step T8>
[0019] In step T8, the control unit determines whether or not the
exhaust temperature has reached a re-ignition temperature. When it
is determined that the re-ignition temperature has been reached,
the process proceeds to step T9, and when it is determined that the
re-ignition temperature has not been reached, the process returns
to step T7.
[0020] <Step T9>
[0021] In step T9, the control unit re-ignites the burner, and the
process proceeds to step T4. As a result, the supply of
high-temperature air for drying to the drum is resumed, and the
temperature inside the drum rises again.
[0022] <Step T10>
[0023] In step T10, the control unit stops the burner and stops the
rotations of the fan and the drum, respectively. As a result, this
flow is ended.
[0024] As described above, a conventional clothes dryer suppresses
an abnormal rise in the temperature inside the drum and the damage
of the clothes due to overheating by repeating the following
processes: when the exhaust temperature from the drum reaches the
predetermined upper limit temperature, the burner (heat source) is
stopped to lower the temperature inside the drum, and thereafter,
when the exhaust temperature reaches the predetermined re-ignition
temperature, the burner is re-ignited.
[0025] However, in the above-described drying operation, even after
the exhaust temperature reaches the upper limit temperature, that
is, moisture contained in the clothes decreases, at least a portion
of the clothes have almost been dried and become excessively dried,
and when the exhaust temperature reaches the re-ignition
temperature, the burner is re-ignited at once so that the
temperature inside the drum is kept high and the surface
temperature of the clothes keeps rising all the time. Such a state
leads to a bruise of clothes, and the clothes dryer performing the
conventional drying operation has room for improvement concerning a
reduction of the damages of the clothes caused by overheating.
[0026] To solve this problem, such a control is considered as
follows: the upper limit temperature is lowered in the latter half
of the operation in which fire extinguishing and ignition of the
burner are repeated, and the burner is stopped before the
temperature inside the drum rises excessively. However, the clothes
dryer cannot distinguish the type, weight, etc. of the clothes
accommodated in the drum, due to the characteristics of the clothes
dryer suitably used particularly for a laundromat, and it is
difficult to determine at what point the latter half of the
operation is. Therefore, it is difficult to adopt such a
control.
[0027] Current Technical Literature
PATENT LITERATURE
[0028] Patent Literature 1: Japanese Laid-Open Patent Publication
No. 9-290095
SUMMARY
[0029] The technical problem to be solved by the present
invention
[0030] An object of the present invention is to effectively solve
such a problem, and it is an object of the present invention to
provide a clothes dryer capable of lowering the temperature in the
latter half of the operation regardless of the type and the amount
of clothes and sufficiently reducing damages to the clothes due to
overheating and drying the entire clothes uniformly.
[0031] The technical solution for solving the technical problem
[0032] In view of the above problems, the present invention adopts
following technical solutions.
[0033] That is, a clothes dryer according to the present invention
includes a drum capable of accommodating clothes, an air supply and
exhaust unit for supplying and discharging air for drying to and
from the drum, a heating unit for heating the air for drying
supplied to the drum, an exhaust temperature detection unit for
detecting the temperature of the air for drying that is discharged
from drum, and a heating control unit for performing a temperature
adjustment processing, the heating unit is stopped when an exhaust
temperature detected by the exhaust temperature detection unit
reaches a predetermined upper limit temperature, and it is
re-operated when the exhaust temperature is lowered to a
predetermined re-ignition temperature to perform a re-ignition. The
heating control unit is provided with a re-ignition temperature
adjustment part that performs an adjustment to lower the
re-ignition temperature and the re-ignition temperature is
gradually lowered through the re-ignition temperature adjustment
part every time when the temperature adjustment processing is
repeated intermittently to perform the re-ignition.
[0034] In particular, it is preferable that the re-ignition
temperature adjustment part lowers the re-ignition temperature in
stages by a predetermined temperature to determine a new
re-ignition temperature every time when the temperature adjustment
processing is performed.
[0035] Furthermore, the re-ignition temperature adjustment part
pre-sets a lower limit value for the re-ignition temperature. When
the temperature adjustment processing is repeated to enable the
re-ignition temperature to reach the lower limit value, the
re-ignition temperature adjustment part keeps the re-ignition
temperature at the lower limit value, and the heating control unit
performs a re-ignition at the re-ignition temperature
thereafter.
[0036] In these cases, it is also preferable that the re-ignition
temperature adjustment part acquires an elapsed time from the
re-ignition until the exhaust temperature reaches a predetermined
upper limit temperature, and adds a correction value to the
predetermined temperature based on the elapsed time.
[0037] In addition, it is preferable that the heating unit is a
non-adjustable burner having no thermal power adjustment
function.
THE EFFECT OF THE PRESENT INVENTION
[0038] According to the present invention described above, the air
for drying heated by the heating unit is supplied into the drum by
an air supply and exhaust unit to dry the clothes, and the point of
time at which the exhaust temperature detected by the exhaust
temperature detection unit exceeds the upper limit temperature is
set to be a substantial boundary between the former half and the
latter half of the drying operation. The point of time at which the
exhaust temperature has reached the upper limit temperature is not
taken as a reference point, but the point of time at which the
exhaust temperature has dropped to the re-ignition temperature is
taken as the reference point of the reheating operation of the
heating unit. It is possible to perform the temperature adjustment
processing by the heating control unit in the latter half of the
drying operation without strictly estimating the type and the
amount of the clothes to be dried. Every time this temperature
adjustment processing is repeated intermittently, the heating
control unit gradually reduces the re-ignition temperature down to
the required temperature through the re-ignition temperature
adjustment part, so that the unheated air for drying is used to dry
the clothes, and the temperature inside the drum can be reliably
lowered to a temperature lower than the temperature during the
previous temperature adjustment processing. Consequently,
regardless of the type and the amount of the clothes to be dried,
the peak temperature in the drum for each temperature adjustment
processing can be gradually reduced in the latter half of the
drying operation to lower the temperature of the clothes in the
overdrying condition, and it is possible to uniformly dry the whole
clothes while sufficiently reducing the damage of clothes by
overheating.
[0039] Particularly, according to the present invention in which a
re-ignition temperature adjustment part gradually lowers the
re-ignition temperature in stages by a predetermined temperature,
it is possible to easily and gently control the above-described
control in which the whole clothes can be dried uniformly while
sufficiently reducing the damage of clothes by overheating.
[0040] Furthermore, according to the present invention in which the
re-ignition temperature adjustment part sets the lower limit value
for the re-ignition temperature, it is possible to prevent the
temperature of the clothes from dropping excessively in the latter
half of the drying operation and ensure necessary drying
performance without causing insufficient drying.
[0041] Furthermore, according to the present invention in which a
correction value is added to the re-ignition temperature in
accordance with the elapsed time from the re-ignition to the stop
of the heating, the presence or absence of the effect generated
through the reduction in the re-ignition temperature is fed back,
and a function of stably reducing temperature inside the drum is
achieved.
[0042] In addition, according to the present invention in which the
heating unit is a non-adjustable burner, the manufacturing cost can
be reduced compared with the case of using the adjustable
burner.
BRIEF DESCRIPTION OF DRAWINGS
[0043] FIG. 1 is a schematic view showing a clothes dryer according
to an embodiment of the present invention;
[0044] FIG. 2 is a block diagram showing structures of the same
clothes dryer;
[0045] FIG. 3 is a flowchart showing a processing procedure of a
drying operation of the same clothes dryer;
[0046] FIG. 4 is a flowchart of FIG. 3 corresponding to a modified
example of the present invention; and
[0047] FIG. 5 is a flowchart showing a processing procedure in a
drying operation of a conventional clothes dryer.
DETAILED DESCRIPTION
[0048] Hereinafter, an embodiment of the present invention will be
described with reference to the drawings.
[0049] FIG. 1 is a schematic view showing a clothes dryer 1
according to an embodiment of the present invention. FIG. 1 (A) is
a front view of a clothes dryer 1, and FIG. 1(B) is a side view of
a clothes dryer 1 according to an embodiment of the present
invention. FIG. 2 is a block diagram showing structures of the
clothes dryer 1.
[0050] The clothes dryer 1 of the present embodiment includes a
device main body 10, a drum 20 and a drum case 21, a drum motor 23,
a burner 30, an air supply and exhaust unit 4, a temperature sensor
(thermistor) 31, a control unit 5 (see FIG. 2), and is particularly
suitably used in a laundromat.
[0051] The interior of the device main body 10 is isolated by an
upper partition plate 11 and a lower partition plate 12. A
combustion chamber 13 is formed at the upper portion thereof, a
drying chamber 14 is formed in the middle portion thereof, and a
ventilation chamber 15 and a fan motor chamber 16 are formed at the
lower portion thereof, respectively.
[0052] The drum 20 is provided in the cylindrical drum case 21 in
the drying chamber 14, and the drum 20 is arranged concentrically
with the drum case 21 with its axis being the front-rear direction
of the clothes dryer main body 1. Further, the drum 20 has a
slightly smaller diameter than the drum case 21 and a large number
of small holes (not shown) provided on its circumferential surface
so that it can repeatedly rotate in the forward direction and the
reverse direction to loosen the clothes. Such a drum 20 can
accommodate the clothes L to be dried.
[0053] An intake port 21a (see FIG. 1 (A)) is formed at the upper
left position of the drum case 21, and the intake port 21a
communicates with a combustion chamber 13 to be described later via
a short ventilation duct 17. An exhaust port 21b (see FIG. 1 (A))
is formed at the lower right position of the drum case 21. The
front side opening of the drum 20 can be tightly closed by the door
22 so as to freely open and close.
[0054] The drum motor 23 is attached to the upper portion on the
rear surface side of the device main body 10. The drum 20 is
rotatably driven by the rotational force of the drum motor 23.
[0055] A burner 30, as a heating unit, is provided in the
combustion chamber 13 and heats the air for drying supplied into
the drum 20 through the small holes. In addition, the burner 30 is
a non-adjustable type burner having no heating power adjusting
function. Gas supply and gas interruption to the burner 30 are
performed by the gas valve 30b shown in FIG. 2. Besides, an igniter
30a (see FIG. 2) is provided in the vicinity of the burner 30.
[0056] The air supply and exhaust unit 4 supplies and exhausts the
air for drying to and from the drum 20, and has a supply and
discharge passage 40, a discharge fan 48a, and a fan motor 48b.
[0057] The supply and discharge passage 40 is constituted by the
combustion chamber 13, the ventilation duct 17, the drum case 21,
the ventilation port 40b formed in the lower partition plate 12 so
as to face the exhaust port 21b, the ventilation chamber 15 and the
fan motor chamber 16.
[0058] The ventilation chamber 15 is formed below the lower
partition plate 12 and is isolated from the fan motor chamber 16 by
a partition plate 44 arranged substantially vertically. Further, an
air filter 45 is disposed so as to straddle the lower end portion
of the shielding plate 42 whose upper end portion is fixed to the
lower partition plate 12 and the lower end portion of the partition
plate 44, and a vent hole 44a is formed at the right position of
the partition plate 44 (see FIG. 1 (A)).
[0059] In the fan motor chamber 16, an exhaust fan 48a on the front
side of the fan partition plate 47 and a fan motor 48b on the rear
side of the fan partition plate 47 for rotating the exhaust fan 48a
are disposed. A ventilation opening 47a (see FIG. 1(A)) is formed
in the upper left portion of the fan partition plate 47.
[0060] The temperature sensor 31, as the exhaust temperature
detection unit, detects the temperature (exhaust temperature) of
the air for drying discharged from the drum 20, and is disposed in
the vicinity of the exhaust fan 48a, that is, the ventilation
opening 47a of the fan partition plate 47. It is difficult to
measure the temperature inside the drum 20 during operation in real
time, but the temperature inside the drum 20 can be indirectly
measured in real time by using the temperature sensor 31.
[0061] The operation of such a clothes dryer 1 is controlled by a
control unit 5 (see FIG. 2) including a microcomputer. The control
unit 5 includes a heating control unit 55, a timer 51, a ROM 53,
and a RAM 54. By executing a program (such as a temperature
adjustment processing to be described later) stored in the ROM 53
by a microcomputer, a pre-set operation is performed. In the RAM
54, data (such as a re-ignition falling temperature N to be
described later) to be used for executing the above program is
temporarily stored.
[0062] The control unit 5 is capable of outputting a fan motor
drive signal to the fan motor 48b and can output a drum motor drive
signal to the drum motor 23.
[0063] The heating control unit 55 is capable of outputting an
ignition signal to the igniter 30a and outputting a gas supply
signal to the gas valve 30b.
[0064] The heating control unit 55 performs the following
temperature adjustment processing as follows: stopping the burner
30 when the exhaust temperature detected by the temperature sensor
31 reaches a predetermined upper limit temperature, and
re-operating the burner 30 to perform a re-ignition when the
exhaust temperature drops to a predetermined re-ignition
temperature. In the present embodiment, for example, the upper
limit temperature is set to be about 70.degree. C., and the
re-ignition temperature is set to be in a range of 40 to 45.degree.
C. in advance.
[0065] Furthermore, the heating control unit 55 has a re-ignition
temperature adjustment part 56 for performing an adjustment to
lower the re-ignition temperature. The re-ignition temperature is
gradually lowered by the re-ignition temperature adjustment part 56
every time when the temperature adjustment processing is repeated
intermittently to perform the re-ignition.
[0066] As described above, a clothes dryer in the present
embodiment includes: a drum 20 capable of accommodating clothes L,
an air supply and exhaust unit 4 for supplying and discharging air
for drying to and from the drum 20, a burner 30, as a heating unit,
for heating the air for drying supplied to the drum 20, a
temperature sensor 31, as an exhaust temperature detection unit,
for detecting the temperature of the air for drying that is
discharged from drum 20, and a heating control unit 55 for
performing a temperature adjustment processing as follows: stopping
the burner 30 when an exhaust temperature detected by the
temperature sensor 31 reaches a predetermined upper limit
temperature, and re-operating the burner 30 to perform a
re-ignition when the exhaust temperature drops to a predetermined
re-ignition temperature. The heating control unit 55 is provided
with a re-ignition temperature adjustment part 56 that performs an
adjustment to lower the re-ignition temperature, and the
re-ignition temperature is gradually lowered through the
re-ignition temperature adjustment part 56 every time when the
temperature adjustment processing is repeated intermittently to
perform the re-ignition.
[0067] With such a configuration, the air for drying heated by the
burner 30 is supplied into the drum 20 by the air supply and
exhaust unit 4 to dry the clothes L, and the point of time at which
the exhaust temperature exceeds the upper limit temperature is set
to be a substantial boundary between the former half and the latter
half of the drying operation. The point of time at which the
exhaust temperature has reached the upper limit temperature is not
taken as the reference point, but the point of time at which the
exhaust temperature has dropped to the re-ignition temperature is
taken as the reference point of the reheating operation of the
burner 30. Thus, it is possible to perform the temperature
adjustment processing by the heating control unit 55 in the latter
half of the drying operation without strictly estimating the kind
and the amount of the clothes L to be dried inside the drum 20.
Every time this temperature adjustment processing is repeated
intermittently, the heating control unit 55 gradually reduces the
re-ignition temperature down to the required temperature through
the re-ignition temperature adjustment part 56, so that the
unheated air for drying continues to dry the clothes L, and the
temperature inside the drum 20 can be reliably lowered to a
temperature lower than the temperature during the previous
temperature adjustment processing. Consequently, regardless of the
type and the amount of clothes L to be dried, the peak temperature
in the drum 20 for every temperature adjustment processing can be
gradually reduced in the latter half of the drying operation to
stably lower the temperature of the clothes L in the overdrying
condition, and it is possible to uniformly dry the whole clothes
while sufficiently reducing the damage of the clothes L by
overheating compared with the current method of keeping a
continuous high-temperature operation.
[0068] Furthermore, in making such an effect, new sensors are
unnecessary, and the conventional mechanic configuration can be
adopted without costs.
[0069] It should be noted that, as another method for lowering the
temperature of the clothes with a boundary as the upper limit
temperature is reached, it is conceivable to lower the upper limit
temperature itself from the time when the exhaust temperature
reaches the upper limit temperature. However, since this method is
carried out after the burner 30 is re-ignited, the time for the
exhaust temperature to reach the upper limit temperature again is
advanced. Thus, the number of times of ignition and extinction of
the burner 30 increases throughout the operation, which is
disadvantageous in terms of the durability of the machine.
[0070] In the present invention, the number of times of ignition
and extinction of the burner 30 is reduced as compared with the
above-described method, which is advantageous also from the aspect
of durability of the machine.
[0071] Also, as described above, when the exhaust temperature
reaches the upper limit temperature for the first time, the surface
of the clothes L is in a substantially dried state, and the dried
portions are more easily damaged by heat compared with the wetted
portion. This point is not noted in the prior art, and the
following idea is also not mentioned: the temperature in the drum
20 is lowered by lowering the re-ignition temperature in a state
where an undried portion possibly remains.
[0072] FIG. 3 is a flowchart showing the processing procedure in
the drying operation of the clothes dryer 1. Hereinafter, the
processing procedure of the drying operation will be specifically
described with reference to FIG. 3. In this case, the initial value
of the re-ignition temperature is set to be 45.degree. C., the
subtraction value (a predetermined value) to decrease the
re-ignition temperature step by step is set to be 1.degree. C., the
cumulative value of the subtraction value is set to be the
re-ignition fall temperature N, and the lower limit of the
re-ignition value is set to be 40.degree. C.
[0073] When the clothes L to be dried is thrown into the drum 20 by
opening the door 22, and the door 22 is closed and a start button
(not shown) is pushed, this flow starts.
[0074] <Step S1>
[0075] In step S1, the control unit 5 outputs a drum motor drive
signal to the drum motor 23 to start the rotation of the drum 20,
and outputs a fan motor drive signal to the fan motor 48b to start
the rotation of the exhaust fan 48a. As a result, the air in the
fan motor chamber 16 is discharged to the outside of the device,
the air flows from the combustion chamber 13 toward the fan motor
chamber 16 to flow to the supply and discharge passage 40, and
supply and exhaust of the air for drying to and from the drum 20 is
started.
[0076] <Step S2>
[0077] In step S2, the heating control unit 55 outputs a gas supply
signal to the gas valve 30b to turn on the gas valve 30b, and also
outputs an ignition signal to the igniter 30a to ignite the burner
30. As a result, a supply of high-temperature air for drying to the
drum 20 is started.
[0078] <Step S3>
[0079] In step S3, the control unit 5 sets the initial value of the
re-ignition falling temperature N to be 0 (.degree. C.).
[0080] <Step S4>
[0081] In step S4, the control unit 5 causes the timer 51 to start
counting the operation time.
[0082] <Step S5>
[0083] In step S5, the control unit 5 determines whether or not the
operation time has reached the end time based on the count value of
the timer 51, and determines whether or not to end the operation.
When it is determined that the operation is to be terminated, the
process proceeds to step S14, and when it is not determined to end
the operation, the process proceeds to step S6.
[0084] <Step S6>
[0085] In step S6, the control unit 5 determines whether or not the
exhaust temperature detected by the temperature sensor 31 has
reached the upper limit temperature. When it is determined that the
exhaust temperature has reached the upper limit temperature, the
process proceeds to step S7, and when it is determined that the
exhaust temperature has not reached the upper limit temperature,
the process returns to step S5. It should be noted that, when the
amount of moisture in the drum 20 is large, even if the
high-temperature air for drying is supplied, the amount of heat is
utilized for the evaporation of water, and the temperature inside
the drum 20 is hard to rise. The more the amount of clothes and the
amount of moisture contained in the clothes are, the more time it
takes for the exhaust temperature to reach the upper limit
temperature. The time depends on the fabric and the amount of the
clothes L and the like. However, when the exhaust temperature
reaches the upper limit temperature for the first time, even if the
surface of the clothes L is dried, the interior still is in a wet
state.
[0086] <Step S7>
[0087] In step S7, the heating control unit 55 stops the supply of
the gas to the burner 30 by the gas valve 30b and stops
(extinguishes) the burner 30.
[0088] <Step S8>
[0089] In step S8, based on the count value of the timer 51, the
control unit 5 determines whether or not the operation time has
reached the end time and determines whether or not to end the
operation. When it is determined that the operation is to be
terminated, the process proceeds to step S14, and when it is
determined not to end the operation, the process proceeds to step
S9.
[0090] <Step S9>
[0091] In step S9, the control unit 5 determines whether or not the
exhaust temperature detected by the temperature sensor 31 has
decreased to the re-ignition temperature. When it is determined
that the exhaust temperature has decreased to the re-ignition
temperature, the process proceeds to step S10, and when it is
determined that the exhaust temperature has not dropped to the
re-ignition temperature, the process returns to step S8.
[0092] <Step S10>
[0093] In step S10, the re-ignition temperature of the gas supply
signal and the ignition signal is lowered by the re-ignition
falling temperature N.degree. C. through the re-ignition
temperature adjuster 56.
[0094] <Step S11>
[0095] In step S11, the heating control unit 55 outputs a gas
supply signal to the gas valve 30b and outputs an ignition signal
to the igniter 30a to re-ignite the burner 30.
[0096] <Step S12>
[0097] In step S12, the heating control unit 55 determines whether
or not the re-ignition temperature has reached the lower limit
value by determining whether or not the re-ignition falling
temperature N has reached the set value (for example, 5.degree.
C.). When it is determined that the re-ignition falling temperature
N is equal to or higher than 5.degree. C., the process proceeds to
step S5, and when it is determined that the re-ignition falling
temperature N is not 5.degree. C. or higher, the process proceeds
to step S13.
[0098] That is, when the re-ignition temperature reaches the lower
limit value, the re-ignition temperature adjustment part 56 keeps
the re-ignition temperature at the lower limit value (40.degree.
C.) by keeping the re-ignition falling temperature N at a set
value. The heating control unit 55 performs a subsequent
temperature adjustment processing at the re-ignition temperature.
For this reason, the temperature of the clothes is prevented from
being excessively lowered, and the required drying performance is
ensured without causing insufficient drying. It should be noted
that, the lower limit of the re-ignition temperature, that is, the
set value of the re-ignition falling temperature N, is not limited
to 5.degree. C. as long as the effect of the present invention can
be exerted.
[0099] <Step S13>
[0100] In step S13, the control unit 5 adds 1.degree. C. to the
re-ignition falling temperature N as a predetermined value. As a
result, the re-ignition falling temperature N increases by
1.degree. C. at a time (each time the re-ignition temperature is
lowered by 1.degree. C.) for each temperature adjustment processing
until the re-ignition falling temperature N reaches the set value
(for example, 5.degree. C.).
[0101] As described above, with respect to the initial value of the
re-ignition temperature, each time the temperature adjustment
processing is performed, the re-ignition falling temperature N is
added incrementally, and thus, the re-ignition temperature is
lowered stage by stage to perform a re-ignition. Therefore, it is
possible to easily realize the above-described control capable of
uniformly drying the entire clothes L while sufficiently reducing
the damage to the clothes L by overheating. Further, the
predetermined value is generally set to be about 1.degree. C., and
thus, the peak temperature in the drum 20 for each temperature
adjustment processing can be reduced in a manner of reducing
damages to the clothes L and ensuring an appropriate temperature
difference that can dry the undried portion in the latter half of
the operation. Further, even if the upper limit arrival time point
of the exhaust temperature deviates from the boundary between the
former half and the latter half of the actual drying operation,
since the re-ignition falling temperature N is added little by
little, the peak temperature in the drum 20 for each temperature
adjustment processing is gradually reduced so that it does not have
a large influence on the drying performance. Of course, the
predetermined value is not limited to 1.degree. C.
[0102] <Step S14>
[0103] In step S14, the heating control unit 55 stops the burner
30, and the control unit 5 stops the rotations of the exhaust air
fan 48a and the drum 20, respectively, thereby terminating the
present flow.
[0104] As described above, the clothes dryer 1 in the present
embodiment has an operation course capable of reducing damages to
the clothes by lowering the temperature of the clothes during
overdrying of the clothes L. It should be noted that, regarding the
clothes dryer 1 in an experiment, the upper limit temperature is
set to be about 70.degree. C., the re-ignition temperature is set
to be at about 40 to 45.degree. C., and the additional time A is
set to be at 5 seconds. When the above experiment is compared with
the case shown in FIG. 5, which indicates the current drying
operation, the peak temperature in the drum 20 during the drying
operation could be reduced by about 10.degree. C. The experimental
values are obtained from the Thermo Label (registered trademark)
capable of measuring the highest temperature in the drum 20.
[0105] It should be noted that, as another method of lowering the
clothes temperature during overdrying, it is considered to use a
thermal power adjustment type burner capable of adjusting the
thermal power in a plurality of stages and adjust the fire power of
the burner to a small value after the exhaust temperature reaches
the upper limit temperature, thereby lowering the temperature of
the clothes.
[0106] In this case, it is considered possible that the number of
times of ignition and extinguishment is suppressed after the fire
power of the burner is adjusted and that there are few problems in
terms of durability of the machine. However, when an adjustable
burner is used, the manufacturing cost of the device rises. In the
present invention, the temperature in the drum 20 is adjusted by
updating the re-ignition falling temperature, and only the ON/OFF
control is enough for the heating unit. Thus, it is possible to use
the non-adjustable burner 30 as the heating unit, and it is
particularly advantageous in terms of the manufacturing cost of
device.
[0107] Although one embodiment of the present invention has been
described above, the specific configuration of each part is not
limited to the above-described embodiment.
[0108] For example, the re-ignition temperature adjustment unit 56
is used to acquire the elapsed time T from the re-ignition until
the exhaust temperature reaches the predetermined upper limit
temperature, and it is effective that the correction value is added
to the re-ignition falling temperature based on the elapsed time
T.
[0109] FIG. 4 is a flow chart corresponding to FIG. 3 showing the
procedure. Common parts are denoted by the same reference numerals,
and the explanations thereof are omitted. Next, the added steps are
described below.
[0110] <Step S13a>
[0111] In step S13a, counting is started for the elapsed time (the
re-ignition elapsed time) since the re-ignition.
[0112] <Step S7a>
[0113] In step S7a, the elapsed time for the exhaust temperature
reaching the upper limit temperature is acquired.
[0114] <Step S9a>
[0115] In step S9a, a correction value a is added to the
re-ignition falling temperature N according to the elapsed time.
That is, when the re-ignition falling temperature N is decreased,
the elapsed time until the predetermined upper limit temperature is
reached after the re-ignition is extended, but the elapsed time may
hardly change depending on the amount of the laundry or the outside
air temperature. Therefore, the re-ignition falling temperature N
will be corrected to N+.alpha.. If both N and a are 1.degree. C.,
the re-ignition temperature will be lowered by 2.degree. C. in
steps S9a and S10. Whether or not the elapsed time has changed is
determined depending on whether or not it has been changed into a
threshold value (for example, 5 seconds). Conversely, in the case
where the elapsed time is greatly extended even by lowering by
1.degree. C. in step S10, a may be configured to take a negative
value depending on the situation.
[0116] By doing so, it is possible to provide a feedback on whether
the effect is good or bad by lowering the re-ignition falling
temperature, and more accurately, the temperature is stably reduced
in the drum.
[0117] In the present embodiment, the burner 30 is used as the
heating unit, but other burners may also be used as long as the
drying air can be heated.
[0118] Furthermore, in the above-described embodiment, the
re-ignition temperature in the subsequent temperature adjustment
processing is determined by adding a predetermined value to the
re-ignition falling temperature N. However, it is not limited to
this, and the next re-ignition temperature can be determined by
setting the re-ignition temperature to be a predetermined variable
with t=0 as an initial value or by multiplying the re-ignition
temperature by a predetermined coefficient. In addition, a new
re-ignition temperature may be determined based on a table in which
the number of repetitions of the temperature adjustment processing
and the re-ignition temperature are associated with each other.
[0119] Various modifications are possible in other configurations
without departing from the technical spirits of the present
invention.
DESCRIPTION OF THE SYMBOLS
[0120] 1: Clothes dryer; 4: Air supply and exhaust unit; 20: Drum;
30: Burner (heating unit); 31: Temperature sensor (exhaust
temperature detection unit); 55: Heating control unit; 56:
Re-ignition temperature adjustment portion; L: Clothes; N:
Re-ignition falling temperature.
* * * * *