U.S. patent application number 12/376134 was filed with the patent office on 2012-12-27 for steam iron.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V.. Invention is credited to Chandra Mohan Janakiraman, Stein Kuiper, Mohankumar Valiyambath Krishnan.
Application Number | 20120324768 12/376134 |
Document ID | / |
Family ID | 38982442 |
Filed Date | 2012-12-27 |
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United States Patent
Application |
20120324768 |
Kind Code |
A1 |
Janakiraman; Chandra Mohan ;
et al. |
December 27, 2012 |
STEAM IRON
Abstract
A steam iron (500) comprises a housing (520) that includes a
water tank (580), a steam chamber (600) and a pressure equalization
conduit (760). The housing (520) includes an airing means (660).
The steam iron is further provided with a mechanism for allowing
air selectively into the water tank (580). The mechanism comprises
a steam trigger (680) that is arranged to close or open the
pressure equalization conduit (760) and the airing means (660)
inversely. The mechanism may also comprise a spring loaded plunger
or an electronic hand sensor.
Inventors: |
Janakiraman; Chandra Mohan;
(Evanston, IL) ; Valiyambath Krishnan; Mohankumar;
(Singapore, SG) ; Kuiper; Stein; (Eindhoven,
NL) |
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS
N.V.
EINDHOVEN
NL
|
Family ID: |
38982442 |
Appl. No.: |
12/376134 |
Filed: |
August 8, 2007 |
PCT Filed: |
August 8, 2007 |
PCT NO: |
PCT/IB07/53129 |
371 Date: |
September 18, 2009 |
Current U.S.
Class: |
38/77.81 ;
38/77.83 |
Current CPC
Class: |
D06F 75/18 20130101 |
Class at
Publication: |
38/77.81 ;
38/77.83 |
International
Class: |
D06F 75/14 20060101
D06F075/14; D06F 75/18 20060101 D06F075/18 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 7, 2006 |
EP |
06118498.2 |
Claims
1. A steam iron comprising a housing, said housing including a
water tank, a steam chamber, a pressure equalization conduit for
equalizing steam pressure between said steam chamber and said water
tank and a mechanism for selectively allowing air into said water
tank through an airing means.
2. A steam iron of claim 1 wherein said water tank is divided by
means of a partition wall into a dosing chamber and a water
reservoir.
3. A steam iron of claim 2 wherein said dosing chamber is at least
three to eight times smaller than said water reservoir.
4. A steam iron of claim 2 comprising a means for communication
between said dosing chamber and said water reservoir.
5. A steam iron of claim 1 wherein said mechanism for selectively
allowing air comprises a steam trigger which is arranged to close
or open said pressure equalization conduit and said means for
communication between said dosing chamber and said water reservoir
inversely.
6. A steam iron of claim 1 wherein said mechanism for selectively
allowing air comprises a spring loaded plunger which is arranged to
close or open said pressure equalization conduit and said means for
communication between said dosing chamber and said water reservoir
inversely.
7. A steam iron of claim 1 wherein said mechanism for selectively
allowing air comprises an electronic hand sensor, said electronic
hand sensor being arranged to activate an electromechanical device
which is arranged to close or open said pressure equalization
conduit and said means for communication between said dosing
chamber and said water reservoir inversely.
8. A steam iron of claim 7 wherein said electronic hand sensor is a
capacitive or an inductive sensor and/or the like.
9. A steam iron of claim 1 wherein said mechanism for selectively
allowing air comprises a steam trigger which is arranged to close
or open said pressure equalization conduit and said airing means
inversely.
10. A steam iron of claim 5 wherein said airing means is arranged
to allow air into said water reservoir only when said steam trigger
is released.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a steam iron, more particularly to
a pressure equalized steam iron.
BACKGROUND OF THE INVENTION
[0002] For a steam iron with a dosing point, water is introduced
drop by drop from a water tank into a heated steam chamber. The
steam, thus generated, passes out through steam outlet openings of
a sole plate and comes into contact with a garment to be ironed.
When the iron is placed on the garment, there is a restriction to
steam flow and pressure builds up in the steam chamber. In order to
equalize the pressure difference between the steam chamber and the
inside of the water tank, the water tank and steam chamber are
connected to each other by means of a pressure equalization tube.
In such irons a constant steam rate is maintained as if the iron
were freely suspended.
[0003] However, such systems have some practical issues such as
steam condensation and overheating of the water tank. When the
water in the water tank of the steam iron is moved back and forth
during the active phase of ironing, water waves are formed in the
water tank. These waves disrupt the pressure equalization. The
steam that enters the water tank from the steam chamber is
condensed on the tank wall by the water waves. With a volume ratio
of approximately 1000 to 1 between water vapour and water, the
condensation results in an undesirable under-pressure in the water
tank and defeats the purpose of the pressure equalization. The
pressure fluctuations in the water tank, which are generated by the
wave movement of the water, also have a disadvantageous effect on
the pressure equilibrium between the steam chamber and water tank
and on the pressure present at the dosing point.
[0004] U.S. Pat. No. 6,745,504 provides a steam iron having a
soleplate with a steam chamber and a water tank. A drip valve
supplies the steam chamber with water from the water tank. The
steam iron contains one or more one-way gas valves between the
water tank and ambient air. These gas valves let air enter the
reservoir in response to the under-pressure in the water tank
caused by movement of water in the water tank. A pressure
equalization conduit is formed in a manually operable rod of the
drip valve, such that only one opening is required in the lower
wall of the water tank. As the pressure equalization conduit is
connecting the drip valve and the water tank, the entire water tank
gets heated up because of steam passage. Further, using the gas
valves to let the air into the water tank requires an additional
design feature. The water movement during the normal ironing
operation results in wave formation disrupting the consistent
steaming performance.
[0005] Philips iron (HD1250) is provided with a pressure
equalization conduit. In this iron, the water tank gets air/steam
through the holes provided in the soleplate of the iron. During
rest or during intervals when steaming is stopped, the condensed
steam in the water tank is replaced by a mixture of steam and air
from the soleplate. The steam in the mixture condenses and further
creates under-pressure. Also the steam enters the water tank
heating the entire water tank.
[0006] It is an object of the invention to provide a steam iron
that mitigates the under-pressure in the water tank to give
consistent steaming performance.
[0007] This object is achieved by the features of the independent
claim. Further developments and preferred embodiments of the
invention are outlined in the dependent claims.
SUMMARY OF THE INVENTION
[0008] In accordance with the invention, there is provided a steam
iron comprising a housing that includes a water tank, a steam
chamber and a pressure equalization conduit. The pressure
equalization conduit equalizes the steam pressure between the steam
chamber and the water tank. The housing includes an airing means.
The steam iron is further provided with a mechanism for selectively
allowing air into the water tank through the airing means. The air
that is selectively let into the water tank, during the intervals
between steaming, prevents under-pressure in the water tank that
occurred due to the condensation of steam, thereby resulting in
consistent steaming performance. Without this kind of concept, the
steam rate would drop drastically over a period of time due to
steam condensation in the water tank creating a vacuum. This
concept prevents replacement of steam by steam and instead replaces
part of the condensed steam by air. This keeps the partial pressure
of steam lower in the space above the water and therefore further
reduces the condensation rate and keeps the system steaming at a
healthy rate.
[0009] According to another embodiment of the invention, the water
tank is divided into a dosing chamber and a water reservoir by
means of a partition wall. Separation of the water reservoir and
the dosing chamber by the partition wall minimizes the waves inside
the dosing chamber because of the smaller volume of water in the
dosing chamber as compared to the entire tank. This ensures more
consistent steaming as well as prevents the water reaching the
pressure equalization conduit. The partition wall disallows waves
and sloshing in the rest of the water tank to disturb the dosing
chamber. This separation also keeps the heat restricted only to the
dosing chamber.
[0010] According to a further embodiment, the dosing chamber is
three to eight times smaller than the water reservoir. As a result,
only a small amount of steam is used for pressure equalization.
This minimizes rapid heating up of the entire water tank.
[0011] According to a preferred embodiment, the dosing chamber and
the water reservoir are connected to each other by a means for
communication. When the means for communication is opened, water
can flow freely from the water reservoir to the dosing chamber.
[0012] According to yet another embodiment of the invention, the
steam iron is provided with a mechanism for selectively allowing
air into the space above the water in the water tank. This
mechanism has a steam trigger that is arranged to open or close the
pressure equalization conduit and the means for communication
between the dosing chamber and water reservoir inversely. When the
pressure equalization conduit is closed, the means for
communication between the dosing chamber and the water reservoir is
opened or when the pressure equalization conduit is opened, the
means for communication between the dosing chamber and the water
reservoir is closed. During ironing, when the steam trigger is
actuated, the communication between the water reservoir and the
dosing chamber is closed. This arrangement disallows waves and
sloshing in the rest of the water tank to disturb the dosing
chamber due to isolation from the water reservoir. Now the pressure
equalization conduit is opened so that the steam from the soleplate
can equalize the pressure. During this time, the flow of water from
the dosing chamber into the soleplate is replaced by steam from the
soleplate. The steam above the water in the dosing chamber
condenses and creates an under-pressure. When the steam iron is at
rest, the steam trigger is not actuated. In this situation, the
pressure equalization conduit is closed and the means for
communication between the dosing chamber and the water reservoir is
opened. The water can freely flow from the water reservoir to the
dosing chamber. The airing means allows air into the water
reservoir which is followed by water gushing into the dosing
chamber to compensate the under-pressure that is created during
ironing. Since the connection to the soleplate is cut-off, further
steam does not enter the dosing chamber.
[0013] According to another embodiment, the mechanism for
selectively allowing air includes a spring loaded plunger. This
acts as an actuator to open or close the pressure equalization
conduit and the means for communication between the dosing chamber
and water reservoir inversely. This provides a user friendly
control of activating the pressure equalization phenomenon.
[0014] According to a further embodiment, the mechanism for
selectively allowing air includes an electronic hand sensor. This
can activate an electromechanical device such as a solenoid to open
or close the pressure equalization conduit and the means for
communication between the dosing chamber and water reservoir
inversely.
[0015] According to yet another embodiment of the invention, the
airing means allows air into the water reservoir only when the
steam trigger is released and the steam iron is at rest. In other
words, during the active phase of ironing, no water can flow from
the water reservoir to the dosing chamber. Therefore, even when the
airing means remains open during steam ironing, little or no air
flows into the reservoir as the water quantity in the water
reservoir remains the same and no replacement by air is needed.
[0016] According to still yet another embodiment of the invention,
the mechanism for selectively allowing air into the water tank is
provided with a steam trigger. The steam trigger opens/closes the
pressure equalization conduit and the airing means into the water
reservoir simultaneously, but inversely. When the steam trigger is
actuated, the pressure equalization conduit is opened and water
dripping onto the soleplate is replaced by steam from the
soleplate. Part of this steam condenses inside the dosing chamber
creating an under-pressure. When the iron is rested and the steam
trigger is released, the pressure equalization conduit is closed
and any under-pressure caused by steam condensation cannot be
replaced by steam from the soleplate. Since the airing means is now
open, air rushes in and compensates for the under-pressure by
pushing water into the dosing chamber. Further, during ironing, as
the airing means is closed, the water reservoir cannot receive air,
the water in the dosing chamber remains at a constant level thus
keeping the steam rate constant for a significant part of the
ironing session. This minimizes the water waves in the rest of the
water tank due to vacuum above the water level as air is not
allowed into the water reservoir while steaming is done.
[0017] These and other aspects of the invention will be apparent
from and elucidated with reference to the embodiments described
hereinafter and the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 shows a steam iron during an active phase of ironing
according to an embodiment of the invention;
[0019] FIG. 2 shows a steam iron in a rest position according to
the embodiment of the invention as shown in FIG. 1;
[0020] FIG. 3 shows a steam iron during an active phase of ironing
according to another embodiment of the invention; and
[0021] FIG. 4 shows a steam iron during a rest position according
to the embodiment of the invention as shown in FIG. 3
DETAILED DESCRIPTION OF EMBODIMENTS
[0022] The present invention will be described with respect to
particular embodiments and with reference to certain drawings but
the invention is not limited thereto. Any reference signs in the
claims shall not be construed as limiting the scope. The drawings
described are only schematic and are non-limiting. In the drawings,
the size of some of the elements may be exaggerated and not drawn
to scale for illustrative purposes. Where the term "comprising" is
used in the present description and claims, it does not exclude
other elements or steps. Where an indefinite or definite article is
used when referring to a singular noun e.g. "a" or "an", "the",
this includes a plural of that noun unless something else is
specifically stated.
[0023] Furthermore, the terms first, second, third and the like in
the description and in the claims, are used for distinguishing
between similar elements and not necessarily for describing a
sequential or chronological order. It is to be understood that the
terms so used are interchangeable under appropriate circumstances
and that the embodiments of the invention described herein are
capable of operation in other sequences than described or
illustrated herein.
[0024] Moreover, the terms top, bottom, over, under and the like in
the description and the claims are used for descriptive purposes
and not necessarily for describing relative positions. It is to be
understood that the terms so used are interchangeable under
appropriate circumstances and that the embodiments of the invention
described herein are capable of operation in other orientations
than described or illustrated herein.
[0025] In FIGS. 1 and 2, a steam iron 100 comprises a housing 120,
which at its underside is closed by a soleplate 140. The soleplate
140 is provided with an ironing plate 160 at its bottom. The
housing accommodates a water tank 180, a steam chamber 200, and a
heating element 220 for heating the soleplate 140 and the steam
chamber 200. Inside the water tank 180 is a partition wall 241
which divides the water tank 180 into a dosing chamber 240 and a
water reservoir 260. The dosing chamber 240 and the water reservoir
260 are interconnected by a means for communication 280. The water
tank can be filled with water via a filling port 300 at the front
of the iron. The housing 120 is also provided with airing means 320
for allowing air into the water tank 180. When the means for
communication 280 is opened, water from the water reservoir 260
enters the dosing chamber 240 and through the airing means 320 air
enters the water reservoir 260. The steam iron 100 has a dosing
point 340 through which water from the dosing chamber 240 passes
drop by drop into the steam chamber 200. A steam regulator 360 can
be accessed from the top outer side of the housing 120. The
temperature of the soleplate is controlled by a thermostat 380. The
thermostat 380 is mounted on the soleplate and is adjustable such
that the user can set the temperature by turning the dial. The iron
100 is provided with a pressure equalization conduit 420 which is a
tube connecting the top of the steam generation chamber 200 to the
top of the dosing chamber 240, significantly above the water level
in the dosing chamber 240 . The mechanism for selectively allowing
air includes a steam trigger 400 which is situated at the top of
the housing 120 as shown in the figure. This steam trigger 400 is
connected to the linkages 242 and 243 communicating simultaneously
with both the pressure equalization conduit 420 and the means for
communication 280. The linkages 242 and 243 are arranged in such a
way that the movement of the steam trigger closes and opens each
connection respectively. More specifically, the arrangement
facilitates closing of the means for communication 280 by pushing
243 down and opening of the pressure equalization conduit 420 by
pushing 242 when the steam trigger 400 is depressed and vice-versa.
In these figures the thick arrow indicates the flow of water, the
arrow with dashes indicates the flow of steam and the other arrow
indicates the flow of air.
[0026] In this embodiment, the steam iron 100 is provided with a
steam jet 440 with which the user could choose to shoot steam from
the front onto a garment through a nozzle by activating a steam
deflector 460. The steam deflector 460 is a mechanical device that
directs steam into the nozzle. The steam iron 100 is provided with
a safety valve 480 which is a mechanical valve that opens at a
pre-set excess pressure inside the water tank and releases steam
from the front through the nozzle. This is a safety feature that
might help release pressure under extraordinary circumstances where
all the steam vents are closed or blocked and pressure builds up
rapidly inside the water tank.
[0027] In FIG. 1, when the steam trigger 400 is depressed during
ironing, the linkage 243 closes the means for communication 280
between the water reservoir 260 and the dosing chamber 240. This
means that no water can flow from the water reservoir 260 to the
dosing chamber 240. Therefore although the airing means 320 remains
open during steam ironing, little or no air flows into the water
reservoir 260 as the water quantity in the water reservoir 260
remains the same and no replacement by air thus is needed. The
linkage 242 opens the connection between the pressure equalization
conduit 420 and the dosing chamber 240 to equalize any pressure
that is exerted. During this time, the water that flows from the
dosing chamber 240 through the dosing point 340 into the steam
chamber 200 and then on to the soleplate 140 is replaced by steam
from the soleplate 140. This steam partially condenses inside the
dosing chamber 240. As the interaction between the water reservoir
260 and the dosing chamber 240 is anulled during steaming, the
steam stays inside the dosing chamber 240 and it results in only
localized pressure equalization. As a consequence, heating is
restricted only to the dosing chamber leaving the water reservoir
cool.
[0028] In FIG. 2, when the iron 100 is rested and the steam trigger
400 is released, the linkage 242 closes the connection between the
dosing chamber 240 and the pressure equalization conduit 420. The
linkage 243 opens the means for communication 280 between the
dosing chamber 240 and the water reservoir 260. The under-pressure,
that develops when the steam above the water in the dosing chamber
240 condenses during the active phases of ironing, is overcome by
water gushing into the dosing chamber 240 and air rushing into the
water reservoir 260 via the airing means 320. Since the connection
to the soleplate via pressure equalization conduit 420 is cut-off,
further steam does not enter the dosing chamber 240. Thus air is
used to overcome under-pressure in the water tank during the
intervals of rest. This concept also ensures that the waves in the
water reservoir 260 do not affect the dosing chamber 240 during
ironing, thereby minimizing the fluctuations in steaming.
[0029] The mechanism for selectively allowing air in may include a
spring loaded plunger (not shown) instead of a steam trigger. The
spring loaded plunger acts as an actuator to open/close the
connection between the pressure equalization conduit 420 and the
dosing chamber 240 and the means for communication 280 between the
dosing chamber 240 and the water reservoir 260 inversely. One end
of the plunger is connected to linkages 242 and 243 communicating
simultaneously with both the pressure equalization conduit 420 and
the means for communication 280. The other end of the plunger
protrudes from the housing 120 of the steam iron 100. When the
plunger is depressed during rest, the linkage 243 opens the means
for communication 280 between the water reservoir 260 and the
dosing chamber 240 and the linkage 242 closes the connection
between the dosing chamber 240 and the pressure equalization
conduit 420. During ironing, when the plunger is released, the
linkage 242 opens the connection between the dosing chamber 240 and
the pressure equalization conduit 420. The linkage 243 closes the
means for communication 280 between the dosing chamber 240 and the
water reservoir 260.
[0030] The mechanism for selectively allowing air in may include an
electronic hand sensor (not shown) instead of a steam trigger or a
spring loaded plunger. The electronic hand sensor may be a
capacitive sensor, an inductive sensor or the like. This sensor
activates an electromechanical device such as a solenoid. The
electromechanical device is connected to the linkages 242 and 243.
During ironing, when the electronic hand sensor senses the hand of
the user on the hand grip, the electronic hand sensor actuates the
electromechanical device which in turn activates the linkage 242
that opens the connection between the dosing chamber 240 and the
pressure equalization conduit 420. The linkage 243 closes the means
for communication 280 between the dosing chamber 240 and the water
reservoir 260. During rest, the linkage 243 opens the means for
communication 280 between the water reservoir 260 and the dosing
chamber 240 and the linkage 242 closes the connection between the
dosing chamber 240 and the pressure equalization conduit 420.
[0031] In FIGS. 3 and 4, a steam iron 500 comprises a housing 520,
which at its underside is closed by a soleplate 540. The soleplate
540 is provided with an ironing plate 560 at its bottom. The
housing accommodates a water tank 580, a steam chamber 600, and a
heating element 620 for heating the soleplate 540 and steam chamber
600. Inside the water tank 580 is a partition wall 590 which
divides the water tank 580 into a dosing chamber 582 and a water
reservoir 584. The dosing chamber 582 and the water reservoir 584
are interconnected by a means for communication 586. The water tank
580 can be filled with water via a filling port 640 at the front of
the iron. The housing 520 is provided with an airing means 660
which is connected to a steam trigger 680 in such a way as to
facilitate the air to go into the water tank 580 when the steam
trigger 680 is not depressed and completely blocking any air flow
into the water tank 580 when the steam trigger 680 is depressed.
The steam iron 500 has a dosing point 700 through which water from
the dosing chamber passes drop by drop into the steam chamber 600.
The steam iron 500 is provided with a steam regulator 720 at the
other end of the dosing point 700 which can be accessed from the
top outer side of the housing 520. The temperature of the soleplate
is controlled by a thermostat 740. The thermostat 740 is mounted on
the soleplate and is adjustable such that the user can set the
temperature by turning the dial. The iron 500 is provided with a
pressure equalization conduit 760 that is basically a tube
connecting the top of the steam generation chamber 600 to the top
part of the dosing chamber 582, significantly above the water level
in the dosing chamber 582. The steam trigger 680 has a linkage 681
to communicate with the pressure equalization conduit 760, arranged
in such a way that the depression of the steam trigger 680 opens
the pressure equalization conduit 760 and vice-versa. The steam
iron 500 is provided with a steam jet 800 with which the user could
choose to shoot steam from the front onto a garment through a
nozzle by activating a steam deflector 810. The steam deflector 810
is a mechanical device that directs steam into the nozzle. The
steam iron 500 is provided with a safety valve 820 which is a
mechanical valve that opens at a pre-set excess pressure inside the
water tank and releases steam from the front through the nozzle. In
these figures the bold arrow indicates the flow of water, the arrow
with dashes indicates the flow of steam and the other arrow
indicates the flow of air.
[0032] In FIG. 3, when the steam trigger 680 is depressed, the
linkage 681 opens the connection between the dosing chamber 582 and
the pressure equalization conduit 760. The water, dripping through
the dosing point 700 into the steam chamber 600 and then onto the
soleplate 540, is replaced by steam from the soleplate 540. Part of
this steam condenses inside the dosing chamber 582 thus creating an
under-pressure. When the steam trigger is depressed, the airing
means 660 is closed and hence the water reservoir 584 cannot suck
in air. As a result, the water in the dosing chamber 582 remains at
a constant level thus keeping the steam rate constant for a
significant part of the ironing session.
[0033] In FIG. 4, when the iron 500 is at rest and the steam
trigger 680 is released, the linkage 681 closes the connection
between the pressure equalization conduit 760 and the dosing
chamber 582. Also when the steam trigger 680 is released, the
airing means 660 is opened and air rushes in to compensate the
under-pressure that is created due to the steam condensation. This
restores the pressure inside the water reservoir 584. As air, which
does not condense under these conditions, is used to compensate the
under-pressure, a good steaming performance is achieved in
subsequent cycles.
[0034] The dosing chamber is substantially smaller than that of the
water reservoir. It is at least three to eight times lower than
that of the water reservoir. The volume of dosing chamber is at
least 40 cc to enable steaming for one minute at the steaming rate
of 40 gm/min. The wider the dosing chamber, the more constant the
steam rate is. The dosing chamber is insert-molded by high
temperature plastics such as for example Ryton. The water reservoir
can be comprised of any conventional plastic.
[0035] The diameter of the dosing point depends on factors such as
diameter, length and location of the pressure equalization conduit.
It can be experimentally determined for each design of the steam
iron.
[0036] The length and internal diameter of the pressure
equalization chamber are so chosen as to avoid condensation and
enable instant pressure equalization with minimum losses and
minimum risk of clogging. The internal diameter of the pressure
equalization conduit is at least 6 mm for good pressure
equalization. The conduit is coated with Teflon to reduce the
wetting of the surface and thereby minimizing the condensation.
[0037] It is to be understood that although preferred embodiments,
specific constructions and configurations, as well as materials,
have been discussed herein for devices according to the present
invention, various changes or modifications in form and detail may
be made without departing from the scope and spirit of this
invention.
* * * * *