U.S. patent number RE48,470 [Application Number 16/359,085] was granted by the patent office on 2021-03-16 for garment steaming device.
This patent grant is currently assigned to KONINKLIJKE PHILIPS N.V.. The grantee listed for this patent is KONINKLIJKE PHILIPS N.V.. Invention is credited to Boon Khian Ching, Yong Jiang, Asok Kumar Kasevan, Gary Chi Yang Lim, Chee Keong Ong, Maarten Theodoor Henric Pelgrim, Yongyuan Shan, Mohankumar Valiyambath Krishnan.
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United States Patent |
RE48,470 |
Valiyambath Krishnan , et
al. |
March 16, 2021 |
Garment steaming device
Abstract
A garment steaming device includes a steam generator (20) having
a heater (22) and an ironing surface (32) against which a fabric of
a garment is locatable. An intermediate section (50) is disposed
between the steam generator and the ironing surface to transfer
heat from the steam generator to the ironing surface so that the
ironing surface is indirectly heated by the steam generator via the
intermediate section. The operating temperature of the ironing
surface is not user selectable during use. Furthermore, the
intermediate section is configured to have a thermal transmittance
so that, during use, heat transfer from the steam generator to the
ironing surface is controlled and the temperature of the ironing
surface is maintained between 90.degree. C. and 155.degree. C. when
the ironing surface is located against a fabric in each of a
stationary condition and a moving condition.
Inventors: |
Valiyambath Krishnan;
Mohankumar (Singapore, SG), Shan; Yongyuan
(Singapore, SG), Jiang; Yong (Singapore,
SG), Ong; Chee Keong (Singapore, SG),
Pelgrim; Maarten Theodoor Henric (Utrecht, NL),
Ching; Boon Khian (Singapore, SG), Lim; Gary Chi
Yang (Singapore, SG), Kasevan; Asok Kumar (Johor,
MY) |
Applicant: |
Name |
City |
State |
Country |
Type |
KONINKLIJKE PHILIPS N.V. |
Eindhoven |
N/A |
NL |
|
|
Assignee: |
KONINKLIJKE PHILIPS N.V.
(Eindhoven, NL)
|
Family
ID: |
50002804 |
Appl.
No.: |
16/359,085 |
Filed: |
March 20, 2019 |
PCT
Filed: |
December 23, 2013 |
PCT No.: |
PCT/IB2013/061284 |
371(c)(1),(2),(4) Date: |
June 29, 2015 |
PCT
Pub. No.: |
WO2014/106793 |
PCT
Pub. Date: |
July 10, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
61748263 |
Jan 2, 2013 |
|
|
|
|
61889069 |
Oct 10, 2013 |
|
|
|
|
61903496 |
Nov 13, 2013 |
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Reissue of: |
14758340 |
Dec 23, 2013 |
9598813 |
Mar 21, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06F
75/10 (20130101); D06F 75/14 (20130101); D06F
75/14 (20130101); D06F 75/10 (20130101); D06F
75/26 (20130101); D06F 75/26 (20130101) |
Current International
Class: |
D06F
75/10 (20060101); D06F 75/14 (20060101); D06F
75/26 (20060101) |
References Cited
[Referenced By]
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Foreign Patent Documents
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Jun 2012 |
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WO |
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WO-2012137095 |
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Oct 2012 |
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WO |
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Primary Examiner: Till; Terrence R
Claims
The invention claimed is:
1. A garment steaming device comprising a steam generator having a
heater, an ironing surface against which a fabric of a garment is
locatable, and an intermediate section .Iadd.configured to have a
thermal transmittance and .Iaddend.disposed between the steam
generator and the ironing surface to transfer heat from the steam
generator to the ironing surface so that the ironing surface is
indirectly heated by the steam generator via the intermediate
section, wherein the .[.operating temperature of the ironing
surface is not user selectable during use and the intermediate
section is configured to have a.]. thermal transmittance.[.that.].,
during use, controls the heat transfer from the steam generator to
the ironing surface to maintain .[.the.]. .Iadd.an operating
.Iaddend.temperature of the ironing surface between 90.degree. C.
and 155.degree. C..[.when the ironing surface is located against a
fabric in each of a stationary condition and a moving condition
relative to the fabric.]., wherein the intermediate section is
further configured to have at least one selected from the group
consisting of (i) a fixed thermal transmittance between 75
W/m.sup.2K and 125 W/m.sup.2K and (ii) a variable thermal
transmittance of a variable heat conductivity material, wherein the
variable heat conductivity material is configured to vary its
thermal transmittance by at least 100% over a change in temperature
of the variable heat conductivity material of 50.degree. C.
2. A garment steaming device according to claim 1, wherein the
product of the thermal transmittance of the intermediate section
and .[.the.]. .Iadd.a .Iaddend.temperature differential between the
steam generator and the ironing surface is less than or equal to
1250 W/m.sup.2 when the temperature of the ironing surface is
145.degree. C. and the ironing surface is located against a fabric
in .[.the.]. .Iadd.a .Iaddend.stationary condition.
3. A garment steaming device according to claim 1, wherein the
product of the thermal transmittance of the intermediate section
and .[.the.]. .Iadd.a .Iaddend.temperature differential between the
steam generator and the ironing surface is greater than or equal to
5500 W/m.sup.2 when the temperature of the ironing surface is
100.degree. C. and the ironing surface is located against a fabric
in .[.the.]. .Iadd.a .Iaddend.moving condition.
4. A garment steaming device according to claim 1, wherein the
steam generator is configured to generate steam at a rate
.Iadd.selected from the group consisting .Iaddend.of .Iadd.(i)
.Iaddend.greater than or equal to 20g/min, and .[.more
preferably.]. .Iadd.(ii) .Iaddend.greater than or equal to
30g/min.
5. A garment steaming device according to claim 1, further wherein
the .[.fixed.]. thermal transmittance .[.is.]. .Iadd.comprises a
fixed thermal transmittance in a range .Iaddend.between 90
W/m.sup.2K and 110 W/m.sup.2K.
6. A garment steaming device according to claim 1, wherein the
steam generator is configured to operate at a temperature between
140.degree. C. and 170.degree. C.
7. A garment steaming device according to claim 1, wherein the
.[.intermediate section is configured to have the.]. .Iadd.thermal
transmittance comprises a .Iaddend.variable thermal
transmittance.
8. A garment steaming device according to claim 7, wherein the
intermediate section comprises .[.the.]. variable heat conductivity
material.
9. A garment steaming device according to claim 8, wherein the
intermediate section is formed from a layer of variable heat
conductivity material.
10. A garment steaming device according to claim 8, wherein the
thermal transmittance of the variable heat conductivity material is
configured to vary by at least 100% when the ironing surface
temperature changes between 100.degree. C. and 145.degree. C.
11. A garment steaming device according to claim 7, wherein the
steam generator is configured to operate at a temperature of
greater than or equal to 160.degree. C.
12. A garment steaming device according to claim 7, wherein the
steam generator is configured to operate at a temperature of less
than or equal to 250.degree. C.
13. A garment steaming device according to claim 7, wherein the
thermal transmittance of the intermediate section is configured to
be less than or equal to 36 W/m.sup.2K when the ironing surface
temperature is 145.degree. C.
14. A garment steaming device according to claim 7, wherein the
thermal transmittance of the intermediate section is configured to
be greater than or equal to 42 W/m.sup.2K when the ironing surface
temperature is 100.degree. C.
15. A garment steaming device according to claim 1, wherein at
least part of the intermediate section is integrally formed with
one or more of the steam generator and the ironing surface.
16. A garment steaming device according to claim 1, wherein the
intermediate section comprises an intermediate layer configured to
act as one or more of a thermal buffer to store heat from the steam
generator and a heat distributor to distribute heat to the ironing
surface.
17. A garment steaming device according to claim 1, wherein the
intermediate section comprises an intermediate plate received
between the steam generator and the ironing surface.
18. A garment steaming device comprising a steam generator having a
heater, a motion sensor configured to detect the operating
condition of the garment steaming device, an ironing surface, and a
controller, wherein the controller is configured to operate the
heater to maintain the steam generator at a first temperature range
when no motion of the garment steaming device is detected by the
motion sensor and the ironing surface is located against a fabric,
and at a second temperature range when motion of the garment
steaming device is detected by the motion sensor and the ironing
surface is located against a fabric, further comprising .[.and.].
an intermediate section disposed between the steam generator and
the ironing surface to transfer heat from the steam generator to
the ironing surface so that the ironing surface is indirectly
heated by the steam generator via the intermediate section, wherein
the intermediate section is configured to have at least one
selected from the group consisting of (i) a fixed thermal
transmittance between 75 W/m.sup.2K and 125 W/m.sup.2K and (ii) a
variable thermal transmittance of a variable heat conductivity
material, wherein the variable heat conductivity material is
configured to vary its thermal transmittance by at least 100% over
a change in temperature of the variable heat conductivity material
of 50.degree. C.
19. A method of operating a garment steaming device having a steam
generator with a heater, an ironing surface, and a motion sensor
configured to detect the operating condition of the garment
steaming device, the method comprising operating the heater to
maintain the steam generator at a first temperature range when no
motion of the garment steaming device is detected by the motion
sensor and the ironing surface is located against a fabric, and
operating the heater to maintain the steam generator at a second
temperature range when motion of the garment steaming device is
detected by the motion sensor and the ironing surface is located
against a fabric, wherein an intermediate section is disposed
between the steam generator and the ironing surface to transfer
heat from the steam generator to the ironing surface so that the
ironing surface is indirectly heated by the steam generator via the
intermediate section, wherein the intermediate section is
configured to have at least one selected from the group consisting
of (i) a fixed thermal transmittance between 75 W/m.sup.2K and 125
W/m.sup.2K and (ii) a variable thermal transmittance of a variable
heat conductivity material, wherein the variable heat conductivity
material is configured to vary its thermal transmittance by at
least 100% over a change in temperature of the variable heat
conductivity material of 50.degree. C.
20. A garment steaming device according to claim 1, wherein the
steam generator is configured to operate at a temperature between
150.degree. C. and 160.degree. C.
21. A garment steaming device according to claim 16, wherein the
intermediate layer comprises a steam channel extending along the
intermediate layer along which steam from the steam generator is
able to flow.
.Iadd.22. A garment steaming device according to claim 1, wherein
the operating temperature of the ironing surface is not user
selectable during use. .Iaddend.
.Iadd.23. A garment steaming device according to claim 1, wherein
the intermediate section further comprises a first intermediate
layer made of a heat conductive metal material. .Iaddend.
.Iadd.24. A garment steaming device according to claim 1, further
comprising a motion sensor configured to detect an operating
condition of the garment steaming device, and a controller, wherein
the controller is configured to operate the heater to maintain the
steam generator at a first temperature range when no motion of the
garment steaming device is detected by the motion sensor and the
ironing surface is located against a fabric, and at a second
temperature range when motion of the garment steaming device is
detected by the motion sensor and the ironing surface is located
against a fabric. .Iaddend.
.Iadd.25. A method of operating a garment steaming device having a
steam generator with a heater, and an ironing surface, and a sensor
configured to detect an operating condition of the garment steaming
device, the method comprising operating the heater to maintain the
steam generator at a first temperature range when a first operating
condition of the garment steaming device is detected by the sensor
and the ironing surface is located against a fabric, and operating
the heater to maintain the steam generator at a second temperature
range when a second operating condition of the garment steaming
device is detected by the sensor and the ironing surface is located
against a fabric, wherein an intermediate section is configured to
have a thermal transmittance and disposed between the steam
generator and the ironing surface to transfer heat from the steam
generator to the ironing surface so that the ironing surface is
indirectly heated by the steam generator via the intermediate
section, wherein the thermal transmittance, during use, controls
the heat transfer from the steam generator to the ironing surface
to maintain an operating temperature of the ironing surface in a
range between 90.degree. C. and 155.degree. C., and wherein the
thermal transmittance comprises at least one selected from the
group consisting of (i) a fixed thermal transmittance between 75
W/m.sup.2K and 125 W/m.sup.2K and (ii) a variable thermal
transmittance of a variable heat conductivity material, wherein the
variable heat conductivity material is configured to vary its
thermal transmittance by at least 100% over a change in temperature
of the variable heat conductivity material of 50.degree. C.
.Iaddend.
.Iadd.26. A method of operating a garment steaming device according
to claim 25, wherein the sensor comprises a motion sensor, the
first operating condition comprises when no motion of the garment
steaming device is detected by the motion sensor, and the second
operating condition comprises when motion of the garment steaming
device is detected by the motion sensor. .Iaddend.
Description
This application is the U.S. National Phase application under 35
U.S.C. .sctn. 371 of International Application No.
PCT/IB2013/061284, filed on Dec. 23, 2013, which claims the benefit
of U.S. Provisional Application No. 61/748,263 filed on Jan. 2,
2013 and U.S. Provisional Application No. 61/889,069 filed on Oct.
10, 2013 and U.S. Provisional Application No. 61/903,496 filed on
Nov. 13, 2013. These applications are hereby incorporated by
reference herein.
FIELD OF THE INVENTION
The present application relates to a garment steaming device. The
present application also relates to a steam iron or a steamer, and
a method of operating a garment steaming device.
BACKGROUND OF THE INVENTION
Garment steaming devices, such as steam irons or hand-held steamers
are used to remove creases from fabric, such as clothes and
bedding. Such a steam iron or hand-held steamer generally comprises
a main body with a handle which is held by a user, and has an
ironing plate with a planar ironing surface which is pressed or
located against the fabric of a garment. A water receiving chamber
and a steam generator are disposed in the main body, so that water
is fed from the water receiving chamber to the steam generator and
converted into steam. The steam is then discharged from the steam
generator through vent holes in the ironing surface towards the
fabric of a garment. The steam is used to heat up and momentarily
moisten the fabric of the garment in an attempt to obtain effective
removal of creases from the fabric.
In a garment steaming device as described above, the ironing
surface is heated to a high temperature which heats up the garment
and enhances the conversion of water into steam. However, the hot
ironing surface may also over heat the garment and cause undesired
consequences such as shine or deformation.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a garment steaming
device which substantially alleviates or overcomes the problems
mentioned above, among others.
The invention is defined by the independent claims; the dependent
claims define advantageous embodiments.
According to the present invention, there is provided a garment
steaming device comprising a steam generator having a heater, an
ironing surface against which a fabric of a garment is locatable,
and an intermediate section disposed between the steam generator
and the ironing surface to transfer heat from the steam generator
to the ironing surface so that the ironing surface is indirectly
heated by the steam generator via the intermediate section, wherein
the operating temperature of the ironing surface is not user
selectable during use and the intermediate section is configured to
have a thermal transmittance so that, during use, heat transfer
from the steam generator to the ironing surface is controlled and
the temperature of the ironing surface is maintained between
90.degree. C. and 155.degree. C. when the ironing surface is
located against a fabric in each of a stationary condition and a
moving condition.
With this arrangement, it is possible to use a single heating means
to maintain the steam generator at a high temperature to allow a
desired steam flow rate produced by the steam generator, whilst
also maintaining the temperature of the ironing surface within a
predetermined range when the ironing surface is in contact with a
fabric of a garment to prevent the fabric from becoming overheated
and causing undesired consequences such as shine or deformation of
a fabric, as well as preventing condensation from forming on the
fabric.
The product of the thermal transmittance of the intermediate
section and the temperature differential between the steam
generator and the ironing surface may be less than or equal to 1250
W/m2 when the temperature of the ironing surface is 145.degree. C.
and the ironing surface is located against a fabric in the
stationary condition.
This means that, when the garment steaming device is disposed
stationary against a fabric, the rate of heat transfer from the
steam generator to the ironing surface is comparative to or less
than the rate of heat loss from the ironing surface to the fabric
when the temperature of the ironing surface is about 145.degree. C.
Therefore, the temperature of the ironing surface stabilises and
does not increase above a threshold level at which the fabric would
be damaged.
The product of the thermal transmittance of the intermediate
section and the temperature differential between the steam
generator and the ironing surface may be greater than or equal to
5500 W/m2 when the temperature of the ironing surface is
100.degree. C. and the ironing surface is located against a fabric
in the moving condition. Therefore, the fabric is restricted from
becoming wet due to steam produced by the steam generator
condensing during use of the garment steaming device.
This means that, when the garment steaming device is moved over a
fabric, the rate of heat transfer from the steam generator to the
ironing surface is comparative to or more than the rate of heat
loss from the ironing surface to the fabric when the temperature of
the ironing surface is about 100.degree. C. Therefore, the
temperature of the ironing surface stabilises and does not drop
below a threshold level at which condensation may form on the
fabric.
In one embodiment, the product of the thermal transmittance of the
intermediate section and the temperature differential between the
steam generator and the ironing surface is less than or equal to
1250 W/m2 when the temperature of the ironing surface is
145.degree. C. and the ironing surface is located against a fabric
in the stationary condition; and the product of the thermal
transmittance of the intermediate section and the temperature
differential between the steam generator and the ironing surface is
greater than or equal to 5500 W/m2 when the temperature of the
ironing surface is 100.degree. C. and the ironing surface is
located against a fabric in the moving condition.
It will be appreciated that the combination of the above threshold
characteristics provides a synergistic effect to ensure that the
heat transfer from the ironing surface to a fabric is maintained
within certain parameters. This enables the ironing surface to be
maintained within both predetermined upper and lower threshold
values to prevent damage to a majority of fabrics and restricting a
fabric from becoming wet due to steam produced by the steam
generator condensing during use of the garment steaming device,
whilst maintaining a sufficiently high temperature of the steam
generator to ensure that a desired steam flow rate is able to be
produced by the steam generator at all times.
The steam generator may be configured to generate steam at a rate
of greater than or equal to 20 g/min, and more preferably greater
than or equal to 30 g/min. Therefore, a sufficient flow rate of
steam is produced to remove creases from fabrics when the
temperature of the ironing surface is minimised
According to one or more embodiments, the thermal transmittance may
be between 75 W/m.sup.2K and 125 W/m.sup.2K, and preferably between
90 W/m.sup.2K and 110 W/m.sup.2K.
The temperature of the ironing surface may be maintained between
100.degree. C. and 145.degree. C. when the ironing surface is
located against a fabric in each of a stationary condition and a
moving condition.
This means that the temperature of the ironing surface is
maintained above a threshold temperature to restrict a fabric from
becoming wet due to steam produced by the steam generator
condensing during use of the garment steaming device, but below a
threshold temperature to minimise the potential for damage to a
fabric.
The steam generator may be configured to operate at a temperature
between 140.degree. C. and 170.degree. C., and preferably between
150.degree. C. and 160.degree. C.
This means that the steam generator is able to maintain a
sufficiently high temperature to ensure that a desired steam flow
rate is produced by the steam generator.
The garment steaming device may further comprise a sensor
configured to determine the operating condition of the garment
steaming device, and a controller, wherein the controller may be
configured to operate the heater to maintain the steam generator at
a first temperature range when a first operating condition is
determined and a second temperature range when a second operating
condition is determined.
Therefore, it is possible to operate the heater in at least two
different states dependent on the operating condition of the
garment steaming device. With such an arrangement it is possible to
increase the operating temperature of the steam generator when the
garment steaming device is being used to press a fabric without
exceeding the desired operating temperature of the ironing
surface.
The sensor may be a motion sensor and the controller may be
configured to operate the heater to maintain the steam generator at
a first temperature range when no motion of the garment steaming
device is detected by the motion sensor, and to operate the heater
to maintain the steam generator at a second temperature range when
motion of the garment steaming device is detected by the motion
sensor.
This means that it is possible for the heater to be operated in
dependence on whether movement of the garment steaming device is
determined. Therefore, it is possible to determine whether the
device is stationary on a fabric, or is being moved over a fabric.
The heat loss from the ironing surface will increase when the
ironing surface is moved over a fabric compared to when the ironing
surface is stationary on a fabric. This means that it is possible
to operate the steam generator at different temperature ranges in
dependence on the movement condition detected by the motion sensor
to ensure that the ironing surface is maintained within desired
threshold values.
The first temperature range may be between 140.degree. C. and
170.degree. C., and the second temperature range may be between
160.degree. C. and 190.degree. C.
An advantage of the above temperature ranges is that it is possible
to maximise the steam rate and minimise or eliminate the occurrence
of spitting and/or water leakage whilst still maintaining the
temperature of the ironing surface below a desired operating
temperature to prevent overheating of a fabric in contact with the
ironing surface.
The plate may be a metal, metal alloy or a thermally conductive
polymer. The plate may be a Mica sheet.
According to one or more embodiments, the intermediate section may
comprise a variable heat conductivity material.
Therefore, an intermediate section having a variable thermal
transmittance may be easily produced.
The intermediate section may be formed from a layer of variable
heat conductivity material.
The thermal conductivity of the variable heat conductivity material
is configured to vary by at least 100% over a temperature change of
the variable heat conductivity material of 50.degree. C.
With this arrangement it is possible to maximise the operating
temperature of the steam generator whilst ensuring that the
temperature of the ironing surface is maintained between 90.degree.
C. and 155.degree. C.
The thermal transmittance of the variable heat conductivity
material may be configured to vary by at least 100% when the
ironing surface temperature changes between 100.degree. C. and
145.degree. C.
With this arrangement the variable heat conductivity material helps
to ensure that the temperature of the ironing surface is maintained
between 90.degree. C. and 155.degree. C., whilst allowing for
fluctuations in the temperature of the steam generator.
The steam generator may be configured to operate at a temperature
of greater than or equal to 160.degree. C.
This helps to maximise the steam rate without spitting and
condensation occurring.
The steam generator may be configured to operate at a temperature
of less than or equal to 250.degree. C.
This helps to ensure that the reliability of the steam generator is
maintained by not operating at an excessive temperature.
The thermal transmittance of the intermediate section may be
configured to be less than or equal to 36 W/m.sup.2K when the
ironing surface temperature is 145.degree. C.
The above parameters of the intermediate section helps to ensure
that the temperature of the ironing surface does not exceed the
upper threshold temperature of 155.degree. C. whilst maintaining a
high operating temperature of the steam generator, irrespective of
the operating condition of the ironing surface, and so will not
damage a fabric.
The thermal transmittance of the intermediate section is configured
to be greater than or equal to 42 W/m.sup.2K when the ironing
surface temperature is 100.degree. C.
The above parameters of the intermediate section helps to ensure
that the temperature of the ironing surface does not drop lower
than the lower threshold temperature of 90.degree. C. whilst
maintaining a high operating temperature of the steam generator,
irrespective of the operating condition of the ironing surface, and
so will not allow condensation to form on a fabric during use.
In one embodiment, the thermal transmittance of the intermediate
section is configured to be less than or equal to 36 W/m.sup.2K
when the ironing surface temperature is 145.degree. C., and greater
than or equal to 42 W/m.sup.2K when the ironing surface temperature
is 100.degree. C., and wherein the thermal transmittance is
configured to vary by at least 100%.
It will be appreciated that the combination of the above
characteristics of the variable thermal transmittance of the
intermediate section provides a synergistic effect to ensure that
the heat transfer from the ironing surface to a fabric is
maintained within certain parameters. This enables the ironing
surface to be maintained within both predetermined upper and lower
threshold values to prevent damage to a majority of fabrics and
restricting a fabric from becoming wet due to steam produced by the
steam generator condensing during use of the garment steaming
device, whilst maintaining a sufficiently high temperature of the
steam generator to ensure that a desired steam flow rate is able to
be produced by the steam generator at all times.
At least part of the intermediate section may be integrally formed
with the steam generator and/or the ironing surface. This means
that ease of manufacturing and assembly is maximised.
The intermediate section may be formed from a single material, a
composite material, or a combination of two or more materials.
The intermediate section may comprise a body having at least one
cavity containing a phase change material. The phase change
material may be in one phase which will enable high thermal
transmittance when the ironing surface temperature is low, for
example, at 100.degree. C. The phase change material will be in
another phase which will enable low thermal transmittance when the
ironing surface temperature is high, for example, at 145.degree.
C.
The intermediate section may comprise an intermediate layer
configured to act as a thermal buffer to store heat from the steam
generator and/or to act as a heat distributor to distribute heat to
the ironing surface. Therefore, heat from the steam generator is
able to be redistributed more evenly over an ironing surface of the
ironing plate.
The intermediate layer may form a steam channel extending along the
layer along which steam from the steam generator is able to
flow.
With this arrangement the steam channel provides a pathway to guide
steam along the intermediate layer. Therefore, the surface area of
the intermediate layer in contact with steam is maximised. As a
result, the temperature of the intermediate layer, and therefore
the ironing surface, is able to be increased at a higher rate,
particularly under demanding heat transfer situations. Therefore,
the ironing surface is able to be heated to its operating
temperature at an increased rate.
Furthermore, channeling steam about the intermediate layer
minimises water leakage from the steam iron as any condensate or
supplied water that has not been converted to steam gets heated up
along the steam path provided.
The steam channel may be formed in an upper face of the
intermediate layer. With this arrangement, the steam channel is
exposed to a face of the steam generator. Therefore, heat transfer
from the steam generator to fluid in the steam channel is
maximised.
The steam channel may be formed in a lower face of the intermediate
layer. Therefore, the steam is able to transfer heat to the ironing
surface more effectively.
An opening may be formed through the intermediate layer to define a
steam path along which steam is able to flow from the steam
generator to the ironing surface. This means that a path along
which steam is able to flow from the steam generator to the ironing
plate is easily provided.
A steam path may be defined around the intermediate layer along
which steam is able to flow from the steam generator to the ironing
plate. Therefore, it is possible to minimise or eliminate the need
to provide openings through the intermediate layer.
The intermediate layer may extend to or over the footprint of the
steam generator. The intermediate layer may also extend to or over
the footprint of the ironing surface.
The intermediate layer may be an intermediate plate received
between the steam generator and the ironing surface. Therefore, the
intermediate layer may be easily formed.
The intermediate layer may be a first intermediate layer and the
intermediate section may comprise a second and further intermediate
layers. The intermediate layers may have differing thermal
properties. The differing thermal properties may include heat
capacity and thermal conductivity. For example, in one embodiment
one intermediate layer may be formed from a plate, such as a Mica
sheet, whereas another intermediate layer may be an air gap
provided between the Mica sheet and one of the steam generator or
ironing plate. Therefore, it is possible to increase the ease of
obtaining the desired thermal properties.
At least one intermediate layer may be an air gap disposed between
the steam generator and the ironing plate.
Steam produced by the steam generator may be receivable in the air
gap. Therefore, the means for steam to be distributed along the air
gap to steam holes in the ironing surface is simplified.
According to another aspect of the invention, there is provided a
garment steaming device comprising a steam generator having a
heater, a motion sensor configured to detect the operating
condition of the garment steaming device, and a controller, wherein
the controller is configured to operate the heater to maintain the
steam generator at a first temperature range when no motion of the
garment steaming device is detected by the motion sensor, and a
second temperature range when motion of the garment steaming device
is detected by the motion sensor.
An advantage of using a motion sensor is that the heat transfer
from the steam generator to the ironing surface can be adjusted
automatically to compensate for the difference in heat loss from
the ironing surface to a fabric when the ironing surface is moved
over a fabric compared to when the ironing surface is stationary on
a fabric.
The garment steaming device may be a steam iron, a cold water
system iron or a garment steamer.
According to another aspect of the invention, there is provided a
method of operating a garment steaming device having a steam
generator with a heater, and a motion sensor configured to detect
the operating condition of the garment steaming device, the method
comprising operating the heater to maintain the steam generator at
a first temperature range when no motion of the garment steaming
device is detected by the motion sensor, and operating the heater
to maintain the steam generator at a second temperature range when
motion of the garment steaming device is detected by the motion
sensor.
These and other aspects of the invention will be apparent from and
elucidated with reference to the embodiments described
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of
example only, with reference to the accompanying drawings, in
which:
FIG. 1 shows an exploded perspective view of a heating assembly for
a steam iron;
FIG. 2 shows a diagrammatic cross-sectional view of the heating
assembly shown in FIG. 1;
FIG. 3 shows a diagrammatic cross-sectional view of another
embodiment of a heating assembly for a steam iron;
FIG. 4 shows an exploded perspective view of another embodiment of
a heating assembly for a steam iron having a steam channel formed
therein; and
FIG. 5 shows a graph plotting an example of required thermal
transmittance against operating temperature of the steam generator
for two different temperatures of the ironing surface.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring now to FIG. 1 and FIG. 2, a heating assembly 10 of a
steam iron is shown. Such a steam iron is generally used to apply
steam to a fabric of a garment to remove creases from the fabric.
The steam iron acts as a garment steaming device. Although in the
embodiments described below the garment steaming device is a steam
iron, it will be understood that the invention is not limited
thereto and that the invention may relate to other types of garment
steaming devices, such as a hand-held garment steamer or the like.
Furthermore, although the embodiments described below will relate
to applying steam to the fabric of a garment, it will be
appreciated that such a steam iron may be used to remove creases
from other fabrics.
The steam iron comprises a housing (not shown) and a handle (not
shown). The handle is integrally formed with the housing, and is
gripped by a user during use of the iron to enable a user to
manoeuvre and position the steam iron.
The heating assembly 10 is received by the housing (not shown). The
heating assembly 10 comprises a steam generator 20 and an ironing
plate 30. The steam generator 20 is received by a sole plate 40.
The steam generator 20 may be integrally formed with the sole plate
40.
The steam generator 20 comprises a body 21 and a heater 22. The
heater 22 is received in the body 21. The heater 22 is integrally
formed in the body 21. The heater 22 extends longitudinally along
the body 21 (only an end extending from the body is shown in FIG. 2
and FIG. 3). The body 21 is formed from a heat conductive material,
such as cast aluminium. Therefore, the body 21 is heated when the
heater 22 is operated. That is, heat is conducted from the heater
22 to raise the temperature of the body 21 of the steam generator
20. The steam generator 20 has a steam generating chamber 23. The
steam generating chamber 23 is defined by the body 21. An inner
surface 24 of the body 21 defines a heated surface of the steam
generating chamber 23.
The steam generating chamber 23 has a fluid inlet 25 and a steam
outlet 26. The fluid inlet 25 provides a passageway to supply water
to the steam generating chamber 23. The steam outlet 26 provides a
passageway to feed steam from the steam generating chamber 23. The
steam outlet 26 is formed by one or more passages extending through
the body 21 of the steam generator 20.
A water receiving chamber (not shown) is disposed in the housing.
Water is stored in the water receiving chamber and is fed to the
fluid inlet 25. A fluid passageway (not shown) communicates between
the water receiving chamber and the steam generating chamber 23 so
that water in the water receiving chamber is able to flow into the
steam generating chamber 23 through the fluid inlet 25. A valve
(not shown), such as a needle valve, is disposed in the fluid
passageway to control the flow of water from the water receiving
chamber into the steam generating chamber 23.
The steam generator 20 has an upper side 27 and a lower side 28. A
temperature sensor 29 communicates with the upper side 27. The
temperature sensor 29 is mounted to the upper side 27 of the steam
generator 20. The temperature sensor 29 is operable to detect the
temperature of the steam generator 20. The temperature sensor 29 is
connected to a controller (not shown). The controller is operable
to determine the temperature of the steam generator 20 in response
to a signal received from the temperature sensor 29. The controller
is operable to control operation of the heater 22 to maintain the
temperature of the steam generator 20 within a predetermined range.
That is, when the steam iron is operated, the controller is
operable to turn the heater 22 on and off in response to the
determined temperature to maintain the temperature of the steam
generator 20 within a desired temperature range. The temperature
sensor 29 and the controller may be a thermostat which is operable
to control the supply of power from a power supply (not shown) to
the heater 22.
The lower side 28 of the steam generator 20 faces the ironing plate
30. The steam outlet 26 of the steam generator is formed in the
lower side 28.
The ironing plate 30 has a lower surface 32 and an upper surface
33. The lower surface 32 forms an ironing surface against which a
fabric is locatable. Steam holes 34 are formed through the ironing
plate 30. The steam holes 34 extend to and are formed in the
ironing surface 32. The steam holes 34 are distributed about the
ironing surface 32. Edges of the steam holes 34 are chamfered to
prevent a fabric catching on the edges when a fabric is disposed
against the ironing surface. Similarly, edges of the ironing
surface 32 of the ironing plate 30 are chamfered.
The upper surface 33 of the ironing plate 30 faces the steam
generator 20. The upper surface 33 of the ironing plate 30 is
spaced from the lower side 28 of the steam generator 20. The
ironing plate 30 is disposed on one side of the housing (not shown)
of the steam iron. The handle is disposed on an opposing side of
the housing to the ironing surface 32. The ironing surface 32 of
the ironing plate 30 is exposed to be located against a fabric to
be pressed. The ironing surface 32 of the ironing plate 30 has a
coating (not shown) to reduce friction.
The heating assembly 10 further comprises an intermediate section
50. The intermediate section 50 includes an intermediate plate 51.
It will be understood that in the present arrangement that the
ironing plate 30 also forms part of the intermediate section 50.
The intermediate plate 51 acts as a first intermediate layer. The
intermediate plate 51 is received between the steam generator 20
and the ironing plate 30, and therefore between the steam generator
20 and the ironing surface 32. The intermediate section 50 is
defined between the lower side 28 of the steam generator 20 and the
ironing surface 32. Attachments, for example attachment elements
31, attach the ironing plate 30 to the intermediate plate 51, and
the intermediate plate 51 to the sole plate 40.
Referring to FIG. 2, the intermediate plate 51 has an upper face 52
and a lower face 53. The intermediate plate 51 is formed from a
heat conductive material such as a metal, a metal alloy or a
thermally conductive polymer. The upper and lower faces 52, 53 are
generally planar and define a panel section 54 therebetween.
The intermediate section 50 also has a second intermediate layer.
The second intermediate layer is an air gap 55. The air gap 55
extends parallel to the intermediate plate 51.
A shoulder 56 protrudes from the lower face 53 of the intermediate
plate 51. The shoulder 56 acts as a spacing means. The shoulder 56
extends from the panel section 54 of the intermediate plate 51. The
shoulder 56 extends around the periphery of the panel section 54.
The shoulder 56 defines the air gap 55, acting as the second
intermediate layer. Therefore, the air gap 55 is formed below the
panel section 54 of the intermediate plate 51.
The ironing plate 30 acts as a third intermediate layer of the
intermediate section 50. The intermediate section 50 is configured
to have a thermal transmittance between the steam generator 20 and
the ironing surface 32 as will be described below.
It will be understood that the intermediate section 50 arrangement
described above is provided with first, second and third
intermediate layers, namely the intermediate plate 51, the air gap
55 formed parallel, and adjacent, to the intermediate plate 51, and
the ironing plate 30. However, it will be understood that the
intermediate section 50 may be formed from a single intermediate
layer, two intermediate layers, or four or more intermediate
layers. In the present arrangement, the upper face 52 of the
intermediate plate 51 is mounted to the lower side 28 of the steam
generator 20.
In the present arrangement the intermediate plate 51 is formed from
a discrete component thermally connected to the steam generator 20
and the ironing plate 30. However, it will be understood that
alternative arrangements are envisaged. For example, in another
arrangement the intermediate plate 51 is integrally formed with one
or both of the steam generator 20 and the ironing plate 30, or is
omitted, so that the intermediate section 50 is integrally formed
with the steam generator 20 and/or the ironing surface 32. In one
embodiment the intermediate section 30 is integrally formed with
the steam generator. That is, the intermediate section and the
steam generator form two portions of the same body. Such an
integrally formed intermediate section may be formed by recesses in
a body which also defines the steam generator. In an alternative
arrangement, the ironing plate itself may form the intermediate
section without any additional parts. In such an arrangement the
ironing surface is formed by a surface of the intermediate section
50.
A steam path 57 is formed through the intermediate section 50. The
steam path 57 comprises steam openings 58 formed through the
intermediate plate 51. The steam openings 58 extend between the
upper and lower faces 52, 53 of the intermediate plate 51.
Alternatively, a single steam opening may be provided. In the
present arrangement, the air gap 55 forms part of the steam path 57
provided through the intermediate layer 50. The steam path 57
provides a pathway for steam to flow from the steam generator 20 to
the ironing plate 30. That is, in the present arrangement, the
steam openings 58 align with the steam outlet passages in the steam
generator 20 and the air gap 55 extends over the steam holes 34 in
the ironing plate 30. Therefore, steam is able to flow from the
steam generating chamber 23 to the steam holes 34 extending in the
ironing surface 32 of the ironing plate 30.
The steam iron does not have a user selectable temperature control.
That is, a user is not able to operate the steam iron to adjust the
temperature of the ironing surface during use of the steam iron. A
conventional steam iron is provided with a user adjustable input
which enables the user to adjust the temperature of the ironing
surface during use. This allows a user to set the temperature of
the ironing surface dependent on the fabric to be ironed to prevent
the fabric against which the ironing surface 32 is positioned from
becoming overheated and causing undesired consequences such as
shine or deformation of the fabric.
From experimentation it has been found that it is possible to
remove creases from a normal range of fabrics used in garments by
using a high steam flow rate and maintaining a low temperature of
the ironing surface. This helps to prevent the ironing surface 32
from becoming overheated. Experiments have found that the heat
transfer rate from an ironing surface to a fabric is substantially
the same for the majority of types of fabric used to produce
garments.
Experiments have found that the temperature of the ironing surface
32 should be maintained below 155.degree. C., and preferably below
145.degree. C., to prevent a fabric from becoming overheated and
causing undesired consequences such as shine or deformation.
Therefore, this provides an upper threshold temperature value for
the ironing surface 32.
It has been determined that the stabilised lowest heat loss rate
from the ironing surface to a fabric used in garments occurs when
the temperature of the ironing plate is at the upper threshold
temperature value and the ironing surface is disposed in a
stationary condition. That is, the ironing surface of the steam
iron is located against the same section of a fabric and is held
static. For example, the heat loss rate from the ironing surface to
a fabric of a garment for a 200 cm.sup.2 ironing surface has been
found to be 25 W when the temperature of the ironing surface is
145.degree. C. Therefore, it has been found through experimentation
that for a fabric used in a garment the stabilised lowest heat loss
at a threshold temperature value of 145.degree. C. is 1250
W/m.sup.2. This means that the heat transfer rate to the ironing
surface 32 should be less than or equal to 1250 W/m.sup.2 when the
temperature of the ironing surface is 145.degree. C., and the
ironing surface is in a stationary condition, so as to prevent the
temperature of the ironing surface 32 from exceeding the higher
threshold temperature value.
Experiments have also found that the temperature of the ironing
surface should be maintained above 90.degree. C., and preferably
above 100.degree. C., to prevent condensation from forming on a
fabric being pressed. Therefore, this provides a lower threshold
temperature value for the ironing surface.
It has been determined that the stabilised highest heat loss rate
from the ironing surface to a fabric used in garments occurs when
the temperature of the ironing plate is at the lower threshold
temperature value and the ironing surface is disposed in a moving
condition on the fabric. That is, the ironing surface of the steam
iron is located against and moved over a portion of a fabric such
that it is not in constant contact with the same section of the
fabric. For example, the heat loss rate from the ironing surface to
a fabric of a garment for a 200 cm.sup.2 ironing surface has been
found to be 110 W when the temperature of the ironing surface is
100.degree. C. Therefore, it has been found through experimentation
that for a fabric used in a garment the stabilised highest heat
loss at a threshold temperature value of 100.degree. C. is 5500
W/m.sup.2. This means that the heat transfer rate to the ironing
surface 32 should be greater than or equal to 5500 W/m.sup.2 when
the temperature of the ironing surface is 100.degree. C., and the
ironing surface 32 is in a moving condition, so as to prevent the
temperature of the ironing surface 32 from falling below the lower
threshold temperature value.
It has also been found that it is necessary to maintain a supply of
steam to the fabric when the temperature of the ironing surface is
maintained between 90.degree. C. and 155.degree. C., and preferably
between 100.degree. C. and 145.degree. C., in order to remove
creases from a range of fabrics used in garments. Therefore, it has
been found that the temperature of the steam generator 20 should be
maintained within said temperature range so that a constant supply
of steam is generated and supplied to the ironing surface 32.
Power is supplied by a power supply unit PSU (not shown) when the
steam iron, acting as a garment steaming device, is operated. The
controller (not shown) is operable to control the supply of power
to the heater, therefore controlling operation of the heater 22.
The heater 22 is received by the body 21 of the steam generator 20,
and so the steam generator 20 is heated to a desired operating
condition. The controller (not shown) is operable to control
operation of heater 22 to maintain the steam generator 20 at the
desired operating condition. With the present arrangement, the
steam generator 20 is operated at a temperature between 140.degree.
C. and 170.degree. C., and preferably between 150.degree. C. and
160.degree. C. This temperature range is provided to ensure that a
sufficient flow rate of steam is produced by the steam generator
when water is provided to the steam generator 20 through the water
inlet 25. That is, the flow rate of steam produced by the steam
generator 20 should be sufficient to remove creases from a range of
fabrics used in garments. In the present arrangement, the desired
flow rate of steam is greater than or equal to 20 g/min, and
preferably greater than or equal to 30 g/min.
The controller (not shown) controls operation of the heater 22 in
dependence on the temperature detected by the temperature sensor 29
to regulate the temperature of the steam generator 20. That is, the
heater 22 is operated to maintain the temperature of the steam
generator 20 to enable the provision of a sufficient steam rate
from the steam generator to provide adequate de-wrinkling of a
fabric disposed against the ironing surface 32.
The steam generator 20 generates steam by an instant steam
generation method. Water is supplied through the water inlet 25 to
be converted to steam. With the steam generator 20 being operated
at a temperature between 140.degree. C. and 170.degree. C., and
preferably between 150.degree. C. and 160.degree. C., steam is able
to be produced at a desired flow rate without excess water
undesirably flowing from the steam generator 20.
The heater 22 is provided to heat both the steam generator 20 to
generate steam, and to heat the ironing surface 32. Therefore, it
has been found that the heater should be configured to provide a
sufficient amount of heat to the steam generator 20 to ensure that
a sufficient level of steam is generated by the steam generator to
enable clothes to be pressed, whilst also ensuring that the
transfer of heat from the steam generator 20 to the ironing plate
30 is maintained within a predetermined range to ensure that the
temperature of the ironing surface 32 is maintained within the
desired temperature thresholds described above.
Therefore, the intermediate section 50 is provided between the
steam generator 20 and the ironing surface 32. The intermediate
section 50 controls the transfer of heat from the steam generator
20 to the ironing surface 32. The intermediate section 50 acts as a
thermal buffer to store heat from the steam generator. The
intermediate section 50 also acts as a heat distributor to
distribute heat to the ironing surface. Therefore, the ironing
plate 30 is indirectly heated by the steam generator 20.
The intermediate section 50 forms a heat transfer layer between the
steam generator 20 and the ironing surface 32. The intermediate
section 50 provided between the steam generator 20 and the ironing
surface 32 acts to control the transfer of heat from the steam
generator 20 to the ironing plate 30. In particular, the
intermediate section 50 restricts heat transfer by conduction from
the steam generator 20 to the ironing plate 30.
Therefore, the provision of the intermediate section 50 provides
for indirect heat transfer from the steam generator 20 to the
ironing surface 32. Therefore, only a single heating means is
required to heat both the steam generator 20 and the ironing
surface 32. The ironing surface 32 is heated by heat transfer from
the intermediate section 50.
The intermediate section 50 is configured to have a thermal
transmittance so that, during use of the steam iron, heat transfer
from the steam generator is controlled and the temperature of the
ironing surface is maintained within the upper and lower threshold
temperature values described above. That is, the range of the
thermal transmittance of the intermediate section 50 controls the
transfer of heat to the ironing surface so that the temperature of
the ironing surface does not fall below a temperature at which
condensation forms on a fabric, and does not exceed a temperature
at which a fabric to be pressed becomes overheated and causing
undesired consequences such as shine or deformation.
The thermal transmittance (h) of a section, such as a material, a
composite material, or a combination of two or more materials is
defined by the following equation:
.function. ##EQU00001##
Wherein: h=thermal transmittance (W/m.sup.2K)
Q=heat transfer rate (W)
A-area of the ironing surface (m.sup.2)
T.sub.SG=temperature of the steam generator (.degree. C.)
T.sub.IS=temperature of the ironing surface (.degree. C.)
Therefore, the thermal transmittance is dependent on the heaty
transfer rate, the area of the ironing surface and the temperature
differential between the steam generator and the ironing surface.
It will be understood that, during use, the temperature of the
steam generator will be higher than the temperature of the ironing
surface. The intermediate section 50 determines the transfer of
heat from the steam generator 20 to the ironing surface 32.
Therefore, a temperature gradient is provided between the steam
generator 20 and the ironing surface 32. The intermediate section
50 also acts as an energy buffer.
With the provision of the intermediate section 50 it is possible to
heat the steam generator 20 to a sufficient temperature to convert
the water fed into the steam generator 20 into steam, whilst
maintaining the ironing surface 32 within a predetermined
temperature range. The intermediate section 50 allows the steam
generator 20 to be heated to a sufficient temperature to allow a
desired steam throughput from the steam generator 20, whilst
maintaining the ironing surface 32 at a desired lower
temperature.
In the present arrangement, the characteristics of the intermediate
section 50 are configured to control the transfer of heat from the
steam generator 20 to the ironing surface 32 so that the
temperature of the ironing surface 32 is operated at a low ironing
temperature at all times during use, that is at a temperature of
less than 155.degree. C., and preferably 145.degree. C., and
greater than 90.degree. C., preferably 100.degree. C., when the
steam generator 20 is operated and heated at a temperature in the
range of 140.degree. C. and 170.degree. C., and preferably between
150.degree. C. and 160.degree. C. It will be understood that,
during use, the temperature of the steam generator will be higher
than the temperature of the ironing surface.
The intermediate section 50 as shown, for example, in FIG. 2 is
configured to have a thermal transmittance so that, during use, the
lowest heat transfer rate from the steam generator to the ironing
surface occurs when the temperature of the ironing surface 32 is at
the upper threshold temperature value and the ironing surface is
disposed in a stationary condition.
Therefore, when the ironing surface is in a stationary condition
against a fabric, the intermediate section 50 has the
characteristic of: h(T.sub.SG1-145).ltoreq.1250 W/m.sup.2
Wherein: h=thermal transmittance (W/m.sup.2K)
T.sub.SG1=temperature of the steam generator (.degree. C.)
That is, the product of the thermal transmittance of the
intermediate section and the temperature differential between the
steam generator and the ironing surface is less than or equal to
1250 W/m.sup.2 when the temperature of the ironing surface is
145.degree. C. and the ironing surface is located against a fabric
in the stationary condition.
The above parameters of the intermediate section 50 helps to ensure
that the temperature of the ironing surface 32 does not exceed the
upper threshold temperature, irrespective of the operating
condition of the ironing surface, and so will not damage a
fabric.
The intermediate section 50 is also configured to have a thermal
transmittance so that, during use, the highest heat transfer rate
from the steam generator to the ironing surface occurs when the
temperature of the ironing surface 32 is at the lower threshold
temperature value and the ironing surface is disposed in a moving
condition.
Therefore, when the ironing surface is in a moving condition
against a fabric, the intermediate section 50 has the
characteristic of: h(T.sub.SG2-100).gtoreq.5500 W/m.sup.2
Wherein: h=thermal transmittance (W/m.sup.2K)
T.sub.SG2=temperature of the steam generator (.degree. C.)
That is, the product of the thermal transmittance of the
intermediate section and the temperature differential between the
steam generator and the ironing surface is greater than or equal to
5500 W/m.sup.2 when the temperature of the ironing surface is
100.degree. C. and the ironing surface is located against a fabric
in the moving condition.
The above parameters of the intermediate section 50 helps to ensure
that the temperature of the ironing surface 32 does not drop lower
than the lower threshold temperature, irrespective of the operating
condition of the ironing surface, and so will not allow
condensation to form on a fabric during use.
The steam generator temperature values (T.sub.SG1 and T.sub.SG2),
as well as the thermal transmittance, h, of the intermediate
section are dependent on the two inequalities discussed above.
Therefore, the values of thermal transmittance of the intermediate
section and the temperature ranges for operating the steam
generator are determined through experimentation by reference to
the inequalities given above for the ironing surface in a
stationary condition against a fabric and the ironing surface in a
moving condition against a fabric.
It will be understood that the temperature of the steam generator
may vary, in particular between when the ironing surface is in each
of a stationary and a moving condition against a fabric. Therefore,
T.sub.SG1 may not equal T.sub.SG2.
The intermediate section 50 ensures that the temperature of the
steam generator 20 is maintained within its predetermined operating
temperature range to ensure that a desired quantity of supply of
steam is provided to the fabric. The intermediate section 50 also
ensures that when a desired flow rate of water is provided to the
steam generator 20 to produce a desired steam flow rate, all the
water is turned into steam without water passing through the steam
outlet 26. If a quantity of water is not turned into steam, then
the water may flow from the steam iron and act to dampen the fabric
being pressed.
It has been found from experimentation that the combination of
providing the ironing surface within the above described operating
range together with providing a high steam flow rate, which is made
possible by maintaining the temperature of the steam generator
provides a good ironing performance for fabrics of garments.
As mentioned above, the intermediate section 50 acts as a heat
distribution layer. That is, the intermediate section 50 acts to
distribute a portion of the heat generated by the heater 22 of the
steam generator 20 to the ironing surface 32 so that the ironing
surface 32 is heated to a desired temperature range. Therefore, it
is possible to use a single heater to heat both the steam generator
20 to produce steam and to heat the ironing surface 32.
Furthermore, the intermediate section 50 is also provided to
distribute heat evenly across the ironing surface 32 to prevent
localised hot spots on the ironing surface 32. That is, the
intermediate section 50 provides an even heat distribution.
The provision of the intermediate section 50 may also limit heat
loss from the steam generator 20 when heat is transferred from the
ironing surface 32 to the fabric of a garment being ironed.
Therefore, a reduction of temperature in the steam generator 20 is
restricted.
It will be understood that one arrangement of the intermediate
section 50 which provides the desired characteristics is described
above. With such an intermediate section 50 the parameters, such as
the dimensions, of the intermediate section 50 are dependent on the
characteristics of the ironing surface 32 and the steam generator
20, for example the size of the ironing surface 32, the steam
generator 20, the contact area between the intermediate section 50
and the steam generator 20 and the contact area with the ironing
plate 30. However, it will be understood that the parameters of the
intermediate section may be easily determined in order to provide
the desired characteristics of the intermediate section.
In the present arrangement, the intermediate section 50 extends
across the footprint of the steam generator 20. In such an
arrangement the steam path 57 from the steam generator to the
ironing surface is formed through the intermediate section 50.
However, in an alternative arrangement the intermediate section 50
may only partially extend across the footprint of the steam
generator 20. In such an arrangement, the intermediate section does
not extend across the footprint of the ironing surface 32. A steam
path is provided around the intermediate section to allow steam to
pass from the steam generator 20 to the ironing surface 32.
In the above described embodiments, the intermediate section 50 is
formed by the intermediate plate 51 together with the air gap 55
forming first and second intermediate layers respectively. However,
in an alternative embodiment, the air gap is omitted. With such an
arrangement, the intermediate plate 51 forms the intermediate
section. One or more steam openings are formed through the
intermediate plate 51 to form a steam path from the steam generator
20 to the steam holes 34 in the ironing surface 32. Alternatively,
a steam path is provided around the intermediate plate 51 to allow
steam to pass from the steam generator 20 to the steam holes 34
extending through the ironing surface 32.
It will be understood that the intermediate section may be formed
from two or more intermediate layers, such as a layer of a metal
alloy and a layer of a heat conductive polymer. In an alternative
arrangement, the intermediate plate, acting as a first intermediate
layer, defines a cavity in which a phase-change material is
received to act as a second intermediate layer.
It will also be understood that the intermediate section disposed
between the steam generator and the ironing plate may comprise more
than two intermediate layers to obtain the desired temperature
gradient between the steam generator and the ironing surface.
In an alternative arrangement, an air gap, forming an intermediate
layer of the intermediate section may be formed on the upper side
of the intermediate plate 51. With such an arrangement, the lower
face 53 of the intermediate plate 51 is mounted to the ironing
plate 30 and the shoulder 56 mounts against the lower side 28 of
the steam generator 20.
Referring to FIG. 3, another embodiment of a heating assembly 60 of
a steam iron is shown. The heating assembly 60 shown in FIG. 3
generally has the same arrangement as the heating assembly 10
described above with reference to FIG. 1 and FIG. 2. Therefore, a
detailed description will be omitted herein. Features and
components that correspond to features and components described
above will retain the same reference numerals for each of
reference. However, in this embodiment an intermediate section
comprises a layer of thermal paste acting as an intermediate layer
61 provided between the lower side 28 of the steam generator 20 and
the upper surface 33 of the ironing plate 30. In such an
arrangement, the openings forming the steam outlets 26 of the steam
generator 20 are aligned with the steam holes 34 in the ironing
surface 32. Although in this embodiment the intermediate section
comprises a layer of thermal paste acting as an intermediate layer
61, it will be understood that the intermediate layer 61 may be
formed from alternative materials to enable the intermediate
section to have the desired thermal transmittance.
In the above described embodiments, it will be understood that the
heater 22 is operated in one operating condition to maintain the
temperature of the steam generator 20 within a predetermined
temperature range. With this arrangement, the temperature of the
steam generator 20 is not user controllable, which simplifies
operation of the steam iron. Furthermore, it is not necessary for a
user to adjust the temperature of the ironing surface dependent on
the fabric to be ironed because the ironing surface is maintained
within a temperature range at which the fabric will not be damaged.
It has been found through experimentation that the temperature of
the ironing surface at which different fabrics which are used to
produce garments become overheated and cause undesired consequences
such as shine or deformation of the fabric varies, whilst the
temperature of the ironing surface at which creases may be removed
when steam is dispensed to the fabric remains substantially
constant. Therefore, as the ironing surface 32 is operated at a low
temperature, whilst a high flow rate of steam is provided, it will
be understood that it is not necessary for a user to select a
different temperature setting dependent on the type of fabric to be
steamed and/or pressed.
In the above arrangements, the heat transfer to the ironing surface
32 from the steam generator is dependent on the arrangement of the
intermediate section, and the heater is controlled to maintain the
temperature of the steam generator within one temperature range.
However, it will be understood that the heat transfer rate is
dependent on the temperature of the steam generator, as well as the
thermal transmittance of the intermediate section. In another
embodiment, the steam iron, acting as a garment steaming device, is
provided with a motion sensor (not shown), acting as an operating
condition sensor. The embodiment described herein is generally the
same as the embodiments described above, and so a detailed
description will be omitted. The motion sensor is arranged to
detect motion of the steam iron. The controller determines movement
of the steam iron in response to motion of the steam iron detected
by the sensor. Therefore, the controller is able to determine
whether the steam iron is in a moving condition or a stationary
condition.
With such an arrangement, the controller is configured to operate
the heater in dependence on the operating condition of the garment
steaming device. The controller is configured to operate the heater
to maintain the steam generator within a first temperature range
when a first operating condition is determined and within a second
temperature range when a second operating condition is determined.
In the present embodiment, the first operating or motion condition
is determined when the sensor detects that the steam iron is in a
stationary condition. The second operating or motion condition is
determined when the sensor detects that the steam iron is in a
moving condition.
With such an arrangement it is possible to increase the operating
temperature of the steam generator 20 when the garment steaming
device is being moved and so is deemed to be actively pressing a
fabric. The heat loss rate from the ironing surface 32 will
increase when the ironing surface 32 is moved over a fabric and so
the temperature of the steam generator 20 is able to be increased
without exceeding the desired operating temperature of the ironing
surface 32. Similarly, the heat loss rate from the ironing surface
32 is minimised when the garment steaming device is stationary on a
fabric and so it is possible to decrease the operating temperature
of the steam generator 20. This allows the temperature of the
ironing surface 32 to be easily maintained below an upper
temperature threshold.
For example, the controller may be configured to operate the heater
22 to maintain the steam generator 20 at a first temperature range
of between 140.degree. C. and 170.degree. C. when it is determined
that the garment steaming device is in a stationary condition, and
to operate the heater 22 to maintain the steam generator 20 at a
second temperature range of between 160.degree. C. and 190.degree.
C. when it is determined that the garment steaming device is in a
moving condition.
An advantage of varying the operating condition of the heater is
that the heat loss from the ironing surface to a fabric is higher
than when the ironing surface is moved over a fabric compared to
when the ironing surface is stationary on a fabric. Therefore, it
is possible to maximise the steam rate generated by the steam
generator and to minimise or eliminate the occurrence of spitting
and/or water leakage whilst still maintaining the temperature of
the ironing surface below a desired operating temperature to
prevent overheating of a fabric in contact with the ironing
surface.
It will be understood that the flow rate of water into the
generator may be controlled by the controller operating the valve
in order to vary the steam flow rate produced.
Although in the above arrangement the operating condition sensor is
a motion sensor, it will be understood that alternative sensing
means may be used to detect whether the ironing surface is being
moved over a fabric. In another embodiment, the intermediate layer
is configured to have a variable thermal transmittance. Such an
embodiment is generally the same as the above described embodiments
and so a detailed description will be omitted herein. It will be
understood that the alternative arrangements of the heating
assembly for a steam iron as described above, and shown in FIGS. 1
to 3 may be used with this embodiment. However, in this embodiment
the intermediate plate 51 is formed from a variable heat
conductivity material. That is, the intermediate plate 51 is formed
from a material configured to have a variable thermal transmittance
dependent on the temperature of the intermediate plate 51. For
example, Isoskin.TM. may be used to form the intermediate plate
51.
It will be understood that in the present application a material
having a fixed thermal transmittance, such as the materials used
for the intermediate layer in the above described embodiments, is a
material which is typically able to vary by a small fraction, for
example, less than 10% of their thermal transmittance over a
temperature change of 40-50.degree. C. It will be understood that
in the present application a material having a variable thermal
transmittance is a material which is able to vary its thermal
transmittance by a substantial amount. That is, a material which is
configured to vary its thermal transmittance by at least 50% over a
change in temperature of 50.degree. C.
In one embodiment the material is configured to vary its thermal
transmittance by at least 100% over a change in temperature of
50.degree. C.
In the present embodiment, the steam generator 20 is operated at a
temperature between 165.degree. C. and 235.degree. C. This
temperature range is provided to maximise the flow rate of steam
that is produced by the steam generator when water is provided to
the steam generator 20 through the water inlet 25.
In the present embodiments, the intermediate section 50 is
configured to have a variable thermal transmittance so that, during
use of the steam iron, heat transfer from the steam generator is
controlled and the temperature of the ironing surface is maintained
within the upper and lower threshold temperature values described
above. That is, the range of the thermal transmittance of the
intermediate section 50 controls the transfer of heat to the
ironing surface so that the temperature of the ironing surface does
not fall below a temperature at which condensation forms on a
fabric, and does not exceed a temperature at which a fabric to be
pressed becomes overheated and causing undesired consequences such
as shine or deformation.
As described above, the thermal transmittance (h) of a section,
such as a material, a composite material, or a combination of two
or more materials is defined by the following equation:
.function. ##EQU00002##
Wherein: h=thermal transmittance (W/m.sup.2K)
Q=wheat transfer rate (W)
A=area of the ironing surface (m.sup.2)
T.sub.SG=temperature of the steam generator (.degree. C.)
T.sub.IS=temperature of the ironing surface (.degree. C.)
Therefore, the thermal transmittance is dependent on the heat
transfer rate, the area of the ironing surface and the temperature
differential between the steam generator and the ironing surface.
It will be understood that, during use, the temperature of the
steam generator will be higher than the temperature of the ironing
surface. The intermediate section 50 determines the transfer of
heat from the steam generator 20 to the ironing surface 32. It will
be understood that the heat transfer rate (W) of a variable heat
conductivity material varies dependent on the temperature of the
variable heat conductivity material. Therefore, a temperature
gradient is provided between the steam generator 20 and the ironing
surface 32. The intermediate section 50 also acts as an energy
buffer.
With the provision of the intermediate section 50 it is possible to
heat the steam generator 20 to a sufficient temperature to convert
the water fed into the steam generator 20 into steam, whilst
maintaining the ironing surface 32 within a predetermined
temperature range. The intermediate section 50 allows the steam
generator 20 to be heated to a sufficient temperature to allow a
desired steam throughput from the steam generator 20, whilst
maintaining the ironing surface 32 at a desired lower
temperature.
In the present arrangement, the characteristics of the intermediate
section 50 are configured to control the transfer of heat from the
steam generator 20 to the ironing surface 32 so that the
temperature of the ironing surface 32 is operated at a low ironing
temperature at all times during use, that is at a temperature of
less than 155.degree. C., and preferably 145.degree. C., and
greater than 90.degree. C., preferably 100.degree. C., when the
steam generator 20 is operated and heated at a temperature in the
range of 165.degree. C. and 235.degree. C. It will be understood
that, during use, the temperature of the steam generator will be
higher than the temperature of the ironing surface.
The characteristics of the intermediate section 50 are configured
to vary the thermal transmittance of the intermediate section 50
dependent on the temperature of the intermediate section 50. That
is, the thermal transmittance characteristics of the intermediate
plate 51 formed from a variable heat conductivity material are
configured to vary dependent on the temperature of the intermediate
pate 51.
In the present embodiment, the thermal transmittance of the
intermediate plate 51, and therefore the intermediate section 50,
is configured to vary so that the thermal transmittance of the
intermediate section 50 is less than or equal to 36 W/m.sup.2K when
the ironing surface temperature is 145.degree. C.
The above parameters of the intermediate section 50 helps to ensure
that the temperature of the ironing surface 32 does not exceed the
upper threshold temperature of 155.degree. C. when the temperature
of the steam generator is between 165.degree. C. and 235.degree.
C., irrespective of the operating condition of the ironing surface,
and so will not damage a fabric.
In the present embodiment, the thermal transmittance of the
intermediate plate 51, and therefore the intermediate section 50,
is also configured to vary so that the thermal transmittance of the
intermediate section 50 is greater than or equal to 42 W/m.sup.2K
when the ironing surface temperature is 100.degree. C.
The above parameters of the intermediate section 50 helps to ensure
that the temperature of the ironing surface 32 does not drop lower
than the lower threshold temperature of 90.degree. C. when the
temperature of the steam generator is between 165.degree. C. and
235.degree. C., irrespective of the operating condition of the
ironing surface, and so will not allow condensation to form on a
fabric during use.
Referring to FIG. 5, a graph is shown plotting an example of
desired thermal transmittance against operating temperature of the
steam generator for two different temperatures of the ironing
surface. In FIG. 5, the temperature of the steam generator is
plotted along the x-axis 85, and the required thermal transmittance
is plotted along the y-axis 86. The inventors have found that the
required thermal transmittance of the intermediate plate 51, and
therefore the intermediate section 50, should be equal to or above
a predetermined value (as shown by line denoted 82) dependent on
the temperature of the steam generator when the ironing surface
temperature is at a lower temperature, for example 100.degree. C.,
to lie in the area denoted 84, and that the required thermal
transmittance of the intermediate plate 51, and therefore the
intermediate section 50, should be equal to or below a
predetermined value (as shown by line denoted 81) dependent on the
temperature of the steam generator when the ironing surface
temperature is at a higher temperature, for example 145.degree. C.,
to lie in the area denoted 83.
It will be seen that for a certain temperature of the steam
generator 20, the minimum required change in the thermal
transmittance of the intermediate plate 51 is shown by the
difference in thermal transmittance values between the lines
denoted 81 and 82.
The intermediate section 50 as shown, for example, in FIG. 2 is
configured to have a variable thermal transmittance so that, during
use, the lowest heat transfer rate from the steam generator to the
ironing surface occurs when the temperature of the ironing surface
32 is at the upper threshold temperature value and the ironing
surface is disposed in a stationary condition.
Therefore, when the ironing surface is in a stationary condition
against a fabric, the intermediate section 50 has the
characteristic of: h(T.sub.SG1-145).ltoreq.1250 W/m.sup.2
Wherein: h=thermal transmittance (W/m.sup.2K)
T.sub.SG1=temperature of the steam generator (.degree. C.)
That is, the product of the thermal transmittance of the
intermediate section and the temperature differential between the
steam generator and the ironing surface is less than or equal to
1250 W/m.sup.2 when the temperature of the ironing surface is
145.degree. C. and the ironing surface is located against a fabric
in the stationary condition.
The above parameters of the intermediate section 50 helps to ensure
that the temperature of the ironing surface 32 does not exceed the
upper threshold temperature, irrespective of the operating
condition of the ironing surface, and so will not damage a
fabric.
The intermediate section 50 is also configured to have a variable
thermal transmittance so that, during use, the highest heat
transfer rate from the steam generator to the ironing surface
occurs when the temperature of the ironing surface 32 is at the
lower threshold temperature value and the ironing surface is
disposed in a moving condition.
Therefore, when the ironing surface is in a moving condition
against a fabric, the intermediate section 50 has the
characteristic of: h(T.sub.SG2-100).gtoreq.5500 W/m.sup.2
Wherein: h=thermal transmittance (W/m.sup.2K)
T.sub.SG2=temperature of the steam generator (.degree. C.)
That is, the product of the thermal transmittance of the
intermediate section and the temperature differential between the
steam generator and the ironing surface is greater than or equal to
5500 W/m.sup.2 when the temperature of the ironing surface is
100.degree. C. and the ironing surface is located against a fabric
in the moving condition.
The above parameters of the intermediate section 50 helps to ensure
that the temperature of the ironing surface 32 does not drop lower
than the lower threshold temperature, irrespective of the operating
condition of the ironing surface, and so will not allow
condensation to form on a fabric during use.
The steam generator temperature values (T.sub.SG1 and T.sub.SG2),
as well as the thermal transmittance, h, of the intermediate
section are dependent on the two inequalities discussed above.
Therefore, the values of thermal transmittance of the intermediate
section and the temperature ranges for operating the steam
generator are determined through experimentation by reference to
the inequalities given above for the ironing surface in a
stationary condition against a fabric and the ironing surface in a
moving condition against a fabric.
It will be understood that the temperature of the steam generator
may vary, in particular between when the ironing surface is in each
of a stationary and a moving condition against a fabric. Therefore,
T.sub.SG1 may not equal T.sub.SG2.
The variable thermal transmittance of the intermediate section 50
ensures that the temperature of the steam generator 20 is
maintained within its predetermined operating temperature range to
ensure that a desired quantity of supply of steam is provided to
the fabric. The variable thermal transmittance intermediate section
50 also ensures that when a desired flow rate of water is provided
to the steam generator 20 to produce a desired steam flow rate, all
the water is turned into steam without water passing through the
steam outlet 26. If a quantity of water is not turned into steam,
then the water may flow from the steam iron and act to dampen the
fabric being pressed.
It has been found from experimentation that the combination of
providing the ironing surface within the above described operating
range together with providing a high steam flow rate, which is made
possible by maintaining the temperature of the steam generator
provides a good ironing performance for fabrics of garments.
As mentioned above, the intermediate section 50 acts as a heat
distribution layer. That is, the intermediate section 50 acts to
distribute a portion of the heat generated by the heater 22 of the
steam generator 20 to the ironing surface 32 so that the ironing
surface 32 is heated to a desired temperature range. Therefore, it
is possible to use a single heater to heat both the steam generator
20 to produce steam and to heat the ironing surface 32.
Furthermore, the intermediate section 50 is also provided to
distribute heat evenly across the ironing surface 32 to prevent
localised hot spots on the ironing surface 32. That is, the
intermediate section 50 provides an even heat distribution.
The provision of the intermediate section 50 may also limit heat
loss from the steam generator 20 when heat is transferred from the
ironing surface 32 to the fabric of a garment being ironed.
Therefore, a reduction of temperature in the steam generator 20 is
restricted.
It will be understood that one arrangement of the intermediate
section 50 which provides the desired characteristics is described
above. With such an intermediate section 50 the parameters, such as
the dimensions, of the intermediate section 50 are dependent on the
characteristics of the ironing surface 32 and the steam generator
20, for example the size of the ironing surface 32, the steam
generator 20, the contact area between the intermediate section 50
and the steam generator 20 and the contact area with the ironing
plate 30. However, it will be understood that the parameters of the
intermediate section may be easily determined in order to provide
the desired characteristics of the intermediate section.
In the present arrangement, the intermediate section 50 extends
across the footprint of the steam generator 20. In such an
arrangement the steam path 57 from the steam generator to the
ironing surface is formed through the intermediate section 50.
However, in an alternative arrangement the intermediate section 50
may only partially extend across the footprint of the steam
generator 20. In such an arrangement, the intermediate section does
not extend across the footprint of the ironing surface 32. A steam
path is provided around the intermediate section to allow steam to
pass from the steam generator 20 to the ironing surface 32.
In the above described embodiments, the intermediate section 50 is
formed by the intermediate plate 51 together with the air gap 55
forming first and second intermediate layers respectively. However,
in an alternative embodiment, the air gap is omitted. With such an
arrangement, the intermediate plate 51 forms the intermediate
section. One or more steam openings are formed through the
intermediate plate 51 to form a steam path from the steam generator
20 to the steam holes 34 in the ironing surface 32. Alternatively,
a steam path is provided around the intermediate plate 51 to allow
steam to pass from the steam generator 20 to the steam holes 34
extending through the ironing surface 32.
It will be understood that the intermediate section may be formed
from two or more intermediate layers, such as a layer having a
variable thermal transmittance and a layer having a fixed thermal
transmittance.
It will be understood that in the present application a material
having a fixed thermal transmittance is a material which is
typically able to vary by a small fraction, for example, less than
10% of their thermal transmittance over a temperature change of
40-50.degree. C. It will be understood that in the present
application a material having a variable thermal transmittance is a
material which is able to vary its thermal transmittance by a
substantial amount. That is, a material which is configured to vary
its thermal transmittance by at least 50% over a change in
temperature of 50.degree. C.
In one embodiment the material is configured to vary its thermal
transmittance by at least 100% over a change in temperature of
50.degree. C.
In an alternative arrangement, the intermediate plate, acting as a
first intermediate layer, defines a cavity in which a phase-change
material is received to act as a second intermediate layer.
It will also be understood that the intermediate section disposed
between the steam generator and the ironing plate may comprise more
than two intermediate layers to obtain the desired temperature
gradient between the steam generator and the ironing surface.
In an alternative arrangement, an air gap, forming an intermediate
layer of the intermediate section may be formed on the upper side
of the intermediate plate 51. With such an arrangement, the lower
face 53 of the intermediate plate 51 is mounted to the ironing
plate 30 and the shoulder 56 mounts against the lower side 28 of
the steam generator 20.
The arrangement of the heating assembly 60 of a steam iron
described above with reference to FIG. 3, may include an
intermediate section comprising a variable heat conductivity
material acting as an intermediate layer 61. Such an arrangement is
generally the same as the embodiment described above with reference
to FIG. 3, and so a detailed description will be omitted. However,
in this embodiment an intermediate section comprises a sheet of
variable heat conductivity material acting as an intermediate layer
61 provided between the lower side 28 of the steam generator 20 and
the upper surface 33 of the ironing plate 30. In such an
arrangement, the openings forming the steam outlets 26 of the steam
generator 20 are aligned with the steam holes 34 in the ironing
surface 32.
In the above described embodiments, it will be understood that the
heater 22 is operated in one operating condition to maintain the
temperature of the steam generator 20 within a predetermined
temperature range. With this arrangement, the temperature of the
steam generator 20 is not user controllable, which simplifies
operation of the steam iron. Furthermore, it is not necessary for a
user to adjust the temperature of the ironing surface dependent on
the fabric to be ironed because the ironing surface is maintained
within a temperature range at which the fabric will not be damaged.
It has been found through experimentation that the temperature of
the ironing surface at which different fabrics which are used to
produce garments become overheated and cause undesired consequences
such as shine or deformation of the fabric varies, whilst the
temperature of the ironing surface at which creases may be removed
when steam is dispensed to the fabric remains substantially
constant. Therefore, as the ironing surface 32 is operated at a low
temperature, whilst a high flow rate of steam is provided, it will
be understood that it is not necessary for a user to select a
different temperature setting dependent on the type of fabric to be
steamed and/or pressed.
In the above arrangements, the heat transfer to the ironing surface
32 from the steam generator is dependent on the arrangement of the
intermediate section, and the heater is controlled to maintain the
temperature of the steam generator within one temperature range.
However, it will be understood that the heat transfer rate is
dependent on the temperature of the steam generator, as well as the
variable thermal transmittance of the intermediate section.
Referring to FIG. 4, another embodiment of a heating assembly 70 of
a steam iron is shown. The heating assembly 70 shown in FIG. 4
generally has the same arrangement as the heating assembly 10
described above with reference to FIG. 1 and FIG. 2. Therefore, a
detailed description will be omitted herein. Features and
components that correspond to features and components described
above will retain the same reference numerals.
The heating assembly 70 has an intermediate section 71. The
intermediate section 71 is formed by an intermediate layer, such as
an intermediate plate 72. The intermediate plate 72 is received
between the steam generator 20 and the ironing plate 30. The
intermediate plate 72 is disposed between the lower side 28 of the
steam generator 20 and the upper surface 33 of the ironing plate
30. The intermediate section 71 may be formed of two or more
intermediate layers (not shown). The intermediate section 71 is
configured to act as a thermal buffer to store heat from the steam
generator.
The intermediate section 71 is also configured to act as a heat
distributor to distribute heat to the ironing surface 32.
The intermediate plate 72 has an upper face 73 and a lower face 74.
The intermediate plate 72 is formed from a heat conductive material
such as a metal, a metal alloy and/or a thermally conductive
polymer. The intermediate plate 72 may be formed from a variable
heat conductive material, for example IsoSkin.TM.. The upper and
lower faces 73, 74 are generally planar and define a panel section
77 therebetween. The intermediate section 71 has a first steam
channel 75 formed in its lower face 74. The first steam channel 75
is disposed to allow steam from the steam generator 20 to flow
along it. The first steam channel 75 extends along the lower face
74 of the intermediate plate 72. The first steam channel 75 has a
base 76 and sidewalls upstanding from the base 76.
The first steam channel 75 provides a pathway to guide steam along
the intermediate section 71. Therefore, the surface area of the
intermediate section 71 in contact with steam flowing from the
steam generator 20 is maximised. As a result, the rate of increase
in temperature of the intermediate plate 72 is maximised when steam
flows along the first steam channel 75.
The lower face 74 of the intermediate plate 72 locates against the
upper surface 33 of the ironing plate 30. The upper surface 33 of
the ironing plate 30 forms a face of the first steam channel 75.
Therefore, the surface area of the ironing plate 30 in contact with
steam flowing from the steam generator 20 is maximised. As a
result, heat transfer to the ironing surface 32 is maximised and
the rate of increase in temperature of the ironing surface 32 is
maximised when steam flows along the first steam channel 75.
Therefore, the ironing surface 32 is able to be heated to its
operating temperature range at an increased rate.
The first steam channel 75 is formed to extend over the steam holes
34 formed in the ironing surface 32 so that steam from the steam
generator 20 is fed to the steam holes 34.
The first steam channel 75 forms part of a steam path formed by the
intermediate section 71. The steam path also comprises steam
openings 78 formed through the intermediate plate 72. The steam
openings 78 communicate with the first steam channel 75.
Alternatively, a single steam opening may be provided.
A second steam channel 79 is formed in the lower side 28 of the
steam generator 20. The second steam channel 79 extends along the
lower side 28 of the steam generator 20. The upper face 73 of the
intermediate plate 72 defines a surface of the second steam channel
79. Alternatively, the second steam channel 79 is formed in the
upper face 73 of intermediate plate 72. It will also be understood
that steam channels may be formed in both the lower side 28 of the
steam generator 20 and the upper face 73 of intermediate plate 72.
The steam openings 78 communicate with the second steam channel 79.
The steam outlet 26 of the steam generator 20 communicates with the
second steam channel 79. The second steam channel 79 forms part of
a steam path formed by the intermediate section 71.
The surface area of the intermediate plate 72 in contact with steam
flowing from the intermediate plate 72 is maximised. As a result,
the rate of increase in temperature of the intermediate plate 72 is
maximised when steam flows along the second steam channel 79. Heat
is transferred from the steam generator 20 to the intermediate
section 71 by conduction, i.e. contact regions, and by convection,
i.e. via steam flow along the channels 75, 79. The intermediate
plate 72 transfers heat to the ironing surface 32 by conduction,
i.e. through contact regions, and convection, i.e. via steam flow
along the channels 75, 79. During ironing, heat is rapidly
dissipated from the ironing surface 32 to the fabric and
consequently, its temperature falls. Temperature of the ironing
surface 32 is increased by conduction, however heat transfer by
steam convection maximises the temperature increase. Potential
condensation on the fabric is therefore avoided by augmenting heat
transfer via steam channeling about the intermediate plate 72.
Furthermore, by increasing the steam path length, any water drops
ejected from the steam generator during steaming also gets
evaporated in the steam channels, thus avoiding water marks on the
fabric. The intermediate plate 72, acting as a heat distribution
plate helps to spread the heat uniformly over the ironing surface
32. So the uniformity of the temperature distribution across the
ironing surface is maximised.
Furthermore, channeling steam about the intermediate section 71
minimises water leakage from the steam iron because any condensate
or supplied water that has not been converted to steam in the steam
generator 20 is heated up and converts to steam as it passes along
the first and second steam channels 75, 79 provided.
The second steam channel may be formed in an upper face of the
intermediate section. With this arrangement, the second steam
channel is exposed to a face of the steam generator. Therefore,
heat transfer to fluid in the steam channel is maximised. With the
embodiments described above with reference to FIG. 4, the operation
condition of the steam generator may also be varied in dependence
on the operating condition of the steam iron. However, it will be
understood that the operating temperature of the ironing surface is
not user selectable during use.
With the arrangements described herein, it will be understood that
it is possible to provide a suitable temperature at the ironing
surface, together with a sufficient flow rate, to allow a user to
iron a wide range of fabrics without the need to adjust the
temperature of the iron. Therefore, the need for a user to adjust
and select a suitable setting for the steam iron is removed.
It will also be understood that with the above arrangement it is
possible for a single heater to be provided to heat the steam
generator and the ironing surface to different temperatures.
Therefore, the need to provide two heaters to heat the steam
generator and the ironing surface to different temperatures is
removed. This minimises the weight, size and cost of the steam
iron.
With the embodiments described above the water receiving chamber
(not shown) is received in the housing. However, it will be
understood that in an alternative arrangement the water receiving
chamber (not shown) is disposed in a base unit spaced from the
housing. With such an arrangement the water receiving chamber (not
shown) is in fluid connection with the fluid inlet of a steam
generating chamber via a flexible hose or the like. This minimises
the weight of the steam iron as the weight of the water stored in
the water receiving chamber is transferred to a base unit and is
not disposed in the iron. The water is delivered from the water
receiving chamber to the steam generating chamber by a fluid pump.
Such an arrangement is also applicable to other garment steaming
devices such as a steamer.
It will be appreciated that the term "comprising" does not exclude
other elements or steps and that the indefinite article "a" or "an"
does not exclude a plurality. A single processor may fulfil the
functions of several items recited in the claims. The mere fact
that certain measures are recited in mutually different dependent
claims does not indicate that a combination of these measures
cannot be used to an advantage. Any reference signs in the claims
should not be construed as limiting the scope of the claims.
Although claims have been formulated in this application to
particular combinations of features, it should be understood that
the scope of the disclosure of the present invention also includes
any novel features or any novel combinations of features disclosed
herein either explicitly or implicitly or any generalisation
thereof, whether or not it relates to the same invention as
presently claimed in any claim and whether or not it mitigates any
or all of the same technical problems as does the parent invention.
The applicants hereby give notice that new claims may be formulated
to such features and/or combinations of features during the
prosecution of the present application or of any further
application derived therefrom.
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