Patent Description:
The invention may be used, for example, in the field of garment care.

Due to the compact size and light weight requirement for the steam generator intended to be implemented in handheld steamers, the risk of a non-complete evaporation of steam/water which is dosed in the steam chamber, is increased. As a result, water droplets may be spread over the garment being treated. This problem is known as "spitting".

To overcome this problem, the steam/water path, also called steam channel, is normally designed as a labyrinth, and is used to extend the path where water is evaporated and to increase the contact surface and time for maximizing evaporation. The steam channel is also used to guide the flow of steam up to reaching the steam outlets of the steam chamber.

Traditionally, the dosing hole for dosing water and/or steam into such a steam generator is located near the front portion of the steam chamber, relatively close to the steam vents to extend the length of the steam channel. The steam channel is shaped such that evaporated steam first travels along the steam channel in direction of a rear portion of the steam chamber, then travels back in direction of the front portion of the steam chamber, where steam will exit the steam chamber via some steam vents.

Traditionally, the steam chamber is closed with a separate cover. The steam chamber and the cover are usually assembled via a mechanical male/female assembly, for example by using ribs made on the upper part of the steam chamber tightly cooperating with grooves stamped on the cover. Some studs elements may also additionally be used to strengthen the assembly, for example studs extending upwards from internal walls of the steam chamber, which are cooperating tightly with holes made in the cover. The steam chamber and the cover are then pressed against each other to create mechanical sealing. Optionally, a gasket extending along those peripheral walls or internal vertical walls defining the steam channel, may additionally be used to further improve the sealing. Additionally, sealing paste may also be used on the mechanical male/female assembly sealing to further improve the water tightness.

An example of such a known steam generator is depicted in <FIG>, <FIG> and <FIG>. <FIG> depicts a first view of a steam generator <NUM> according to the prior art, <FIG> depicts a second view of a steam generator <NUM> as depicted in <FIG>,and <FIG> depicts an internal view of a steam generator <NUM> as depicted in <FIG>.

As depicted in <FIG>, the steam generator <NUM> comprises a steam chamber <NUM> for generating steam. The steam chamber <NUM> extends between a front portion FP and a rear portion RP of the steam chamber <NUM>. At least one steam outlet <NUM> is arranged at the front portion FP and receives steam from the steam chamber <NUM>. The steam generator <NUM> also comprises a heating element <NUM> for heating the steam chamber <NUM>. The steam generator <NUM> also comprises a cover <NUM> adapted to take a closed position for closing the steam chamber <NUM>, as illustrated in <FIG>. The steam generator <NUM> also comprises a dosing hole <NUM> arranged in the cover <NUM>, for receiving water and/or steam from outside the steam generator <NUM>. The dosing hole <NUM> is arranged at proximity of the front portion FP when the cover <NUM> is in the closed position. The steam generator <NUM> also comprises a steam channel <NUM> extending between the dosing hole <NUM> and the steam outlet <NUM>. A gasket G1 is arranged between internal vertical walls of the steam channel <NUM>, and the cover. <FIG> illustrates in dotted lines the back and forth steam path between the dosing point and the steam outlets <NUM>.

In the steam chamber using this type of sealing between the steam chamber and the cover, it may happen that the sealing function is compromised. This may happen for example when internal pressure has partially deformed the cover where the sealing was initially made, or when the gasket gets deteriorated over time resulting in a certain porosity or permeability. When the sealing function is compromised, some water droplets in the area where is arranged the dosing hole, so relatively close to the steam outlets, may directly be pushed across the internal walls forming the steam channel at the proximity of the steam outlets, and thus exit the steam outlets before being evaporated. This will cause spitting at the exit of the steam chamber. The user experience will be affected, because water droplets will be spread on the garment being treated.

A steam generator with the features of the preamble of claim <NUM> is known from <CIT>.

This invention provides a new design to overcome above-mentioned problems.

It is an object of the invention to propose an improved steam generator which substantially alleviates or overcomes the problems mentioned above.

To this end, the steam generator according to the invention comprises:.

Arranging the dosing hole at proximity of the rear portion of the steam chamber, when the sealing between the steam chamber and the cover is compromised, prevents water droplets in the area where is arranged the dosing hole, from reaching the steam outlets, contrary to the steam generator of the prior art. Indeed, the relatively large distance between the dosing hole and the steam outlets makes it very difficult to have those water droplets passing across a plurality of internal walls forming the steam channel, up to reaching the steam outlets.

As a result, even if the sealing between the steam chamber and the cover gets compromised, the risk to see water droplets spitting through the steam outlets is very limited, which is very advantageous when this steam generator is implemented in a handheld steamer. The user experience of ironing garments is thus improved.

Moreover, arranging the dosing hole at proximity of the rear portion of the steam chamber means that the most energy absorbing area is around this rear portion. As a result, if the steam chamber is energized uniformly, the coolest point of the steam chamber will be around this rear portion. This also means that the front portion of the steam chamber will keep at a relatively higher temperature, which will further prevent any spitting problem that could be caused by condensation at the steam outlets.

Particular aspects of the invention will now be explained with reference to the embodiments described hereinafter and considered in connection with the accompanying drawings, in which identical parts or sub-steps are designated in the same manner:.

<FIG> depicts a first (exploded) view of a steam generator <NUM> according to the invention, and <FIG> depicts a second (assembled) view of a steam generator as depicted in <FIG>.

The steam generator <NUM> comprises a steam chamber <NUM> for generating steam. The steam chamber <NUM> extends between a front portion FP and a rear portion RP. The steam generator <NUM> also comprises at least one steam outlet <NUM> arranged at the front portion FP and receiving steam from the steam chamber <NUM>.

The steam generator <NUM> also comprises a heating element <NUM> for heating the steam chamber <NUM>.

The steam generator <NUM> also comprises a cover <NUM> adapted to take a closed position for closing the steam chamber <NUM>. This closed position is depicted in <FIG>.

The steam generator <NUM> also comprises a dosing hole <NUM> arranged in the cover <NUM>, for receiving water and/or steam from outside said steam generator <NUM>. The dosing hole <NUM> is arranged at proximity of the rear portion RP when the cover <NUM> is in said closed position, as illustrated in <FIG>.

The front portion FP corresponds to the vertical wall arranged at the front part of the steam chamber <NUM>.

The rear portion RP corresponds to the vertical wall arranged at the rear part of the steam chamber <NUM>.

Preferably, the proximity of the dosing hole <NUM> compared to the rear portion RP is such that the dosing hole <NUM> is arranged within half-length L1=L/<NUM> of the steam chamber length L, starting from the rear portion RP. This is illustrated in the top view <FIG>.

Preferably, the dosing hole <NUM> is arranged along a longitudinal symmetrical axis (AA) of the steam chamber <NUM>. Indeed, given that the garment care product implementing the steam generator <NUM> according to the invention has usually a limited height and a relatively curved shape, there are more space for arranging the dosing hole <NUM> along the longitudinal symmetrical axis (AA).

The steam chamber <NUM> extends along the longitudinal symmetrical axis (AA) between the rear portion RP and the front portion FP.

Preferably, the aperture of the dosing hole <NUM> shall be at least <NUM> in diameter or <NUM> mm2 in area with a minimum dimension of at least <NUM>, as stipulated in paragraph <NUM> of IEC IEC60335-<NUM>-<NUM> standard.

The steam chamber <NUM> further comprises a steam channel <NUM> extending between the dosing hole <NUM> and the at least one steam outlet <NUM>.

The steam channel <NUM> comprises at least two walls arranged substantially perpendicular to the longitudinal symmetrical axis (AA). This embodiment will be further described along with <FIG>.

Term "substantially perpendicular" refers to an angle in the range <NUM>-<NUM> degrees. In other words, said at least two walls are substantially parallel compared to each other.

Preferably, each of two given consecutive walls taken among said at least two walls are arranged to define a steam passage on an opposite side compared to the other wall.

Preferably, the steam chamber <NUM> further comprises a first additional wall arranged between said at least one steam outlet <NUM> and the wall taken among said at least two walls being the closest to the front portion FP:
In a first implementation, the first additional wall comprises a single steam passage in its middle part. This single steam passage improves the steam distribution towards the at least one steam outlets <NUM>. This embodiment will be further described along with <FIG>.

In a second implementation, in addition to a steam passage in its middle part, the first additional wall also comprises steam passages on the left and on the right of said steam passage being in the middle part. Those steam passages on the left and on the right allow a smooth steam flow, so that any carried scale in the steam flow will be easily flushed out. This embodiment will be further described along with <FIG>.

Preferably, the steam chamber <NUM> further comprises a second additional wall arranged in front the steam passage of said first additional wall. The second additional wall comprises two steam passages on its lateral sides. This second additional wall acts as a front barrier which is used to divert the steam flow to the sides. This contributes reducing the risk of water spitting. This embodiment will be further described along with <FIG>.

The dosing hole <NUM> is preferably arranged in the cover <NUM> between the rear portion RP and the wall taken among said at least two walls which is the closest to the rear portion RP.

In case the dosing hole <NUM> is arranged further away from the rear portion RP, the at least two walls are also arranged further away in direction of the front portion FP.

Preferably, a gasket G2 is arranged between the steam chamber <NUM> and the cover <NUM>. For example, the gasket G2 extends over (part of) the top part of internal walls defining the steam channel <NUM>. The gasket G2 may also extend along the peripheral walls of the steam chamber <NUM>, as illustrated in <FIG>.

Some specific embodiments of the steam generator <NUM> introduced above will now be provided in the following.

<FIG> depicts a first embodiment of a steam generator according to the invention.

In this embodiment, the number of the at least two walls is two:.

The first wall W1 is dimensioned such that it does not extend completely to the right side of the steam chamber <NUM>, so that a first steam passage SP1 is formed between the right extremity of the first wall W1 and the right lateral wall of the steam chamber <NUM>.

The second wall W4 is dimensioned such that it does not extend completely to the left side of the steam chamber <NUM>, so that a second steam passage SP4 is formed between the left extremity of the second wall W4 and the left lateral wall of the steam chamber <NUM>.

The first wall W1 and the second wall W4 define a single S-shape for the steam channel <NUM>.

The single S-shape for the steam channel <NUM> increases the length of the steam channel, so this overall improves the evaporation efficiency of the steam generator.

The steam flow is illustrated by dotted lines starting from the dosing hole <NUM>. The steam follows a single S-shape up to reaching and exiting the at least one steam outlets <NUM>. For example, as illustrated, the number of steam outlets is seven.

<FIG> depicts a second embodiment of a steam generator according to the invention.

This embodiment is based on the embodiment of <FIG>.

In addition, the steam channel <NUM> further comprises a first additional wall W5 arranged between the at least one steam outlet <NUM>, and the wall which is the closest to the front portion FP, corresponding to the second wall W4 in that example. The first additional wall W5 is arranged to define a single steam passage SP5 in its middle part.

Preferably, the first additional wall W5 is substantially parallel to the first wall W1 and to second wall W4.

By arranging a single steam passage SP5 in the middle part of the first additional wall W5, steam cannot exit on the lateral extremities of the first additional wall W5 and is thus forced to pass through this central steam passage. In other words, this arrangement creates a "dead" zone on the right side between the second wall W4 and the first additional wall W5, which helps to trap water droplets that would not have fully evaporated into steam yet.

Preferably, the steam passage SP5 extends completely to the bottom part of the steam chamber <NUM>.

Preferably, the steam passage SP5 has a width of at least <NUM>.

<FIG> depicts a variant of the embodiment depicted in <FIG>.

In addition to the steam passage SP5 being in the middle part of the first additional wall W5, the first additional wall W5 also comprises:.

Preferably, the steam passages SP5L and SP5R have a width of at least <NUM>.

Preferably, the steam passage SP5L and the steam passage SP5R do not extend completely to the bottom part of the steam chamber <NUM>. Instead, the steam passage SP5L and the steam passage SP5R define a step having a certain height H1 having a value smaller than an inside height H2 of the steam chamber <NUM>, as illustrated in the cross-sectional view BB of <FIG>.

The advantage of those steps defined by SP5L and SP5R is to avoid water spitting.

Preferably, the central steam passage SP5 can also have similar step.

<FIG> depicts a third embodiment of a steam generator according to the invention.

In addition, the steam channel <NUM> further comprises a second additional wall W6 arranged in front the single steam passage of the first additional wall W5. The second additional wall W6 is arranged to define two steam passages (SP61, SP62) on its lateral sides.

A first steam passage SP61 is formed between the left extremity of the second additional wall W6 and the left lateral wall of the steam chamber <NUM>.

A second steam passage SP62 is formed between the right extremity of the second additional wall W6 and the right lateral wall of the steam chamber <NUM>.

Preferably, the second additional wall W6 is substantially parallel to the first additional wall W5.

<FIG> depicts a fourth embodiment of a steam generator according to the invention.

In this embodiment, the number of the at least two walls is four. To this end, compared to the first embodiment of <FIG>, the steam channel <NUM> further comprises a third wall W2 and a fourth wall W3 which are both arranged between the first wall W1 and the second wall W4.

Increasing the number of the walls to four allows increasing the length of the steam channel and the time water droplets will have to evaporate. As a result, the steam generator will have an increased steaming performance by being able to evaporate more efficiently water.

The third wall W2 is dimensioned such that it does not extend completely to the left side of the steam chamber <NUM>, so that a third steam passage SP2 is formed between the left extremity of the third wall W2 and the left lateral wall of the steam chamber <NUM>. The fourth wall W3 is dimensioned such that it does not extend completely to the right side of the steam chamber <NUM>, so that a fourth steam passage SP3 is formed between the right extremity of the fourth wall W3 and the right lateral wall of the steam chamber <NUM>.

The first wall W1 and the third wall W2 define a single S-shape portion for the steam channel <NUM>, and the fourth wall W3 and the second wall W4 define a single S-shape portion for the steam channel <NUM>. In other words, the four walls (W1, W2, W3, W4) define a double S-shape for the steam channel <NUM>.

The double S-shape for the steam channel <NUM> further increases the length of the steam channel, so this overall improves the evaporation efficiency of the steam generator.

Preferably, each of the steam passage SP1, SP2, SP3 or SP4 defines a surface in the range [<NUM>;<NUM>] mm2.

<FIG> depicts a fifth embodiment of a steam generator according to the invention.

In addition, the first additional wall W5 has been arranged similarly as in <FIG>.

<FIG> depicts a sixth embodiment of a steam generator according to the invention,.

In addition, the second additional wall W6 has been arranged similarly as in <FIG>.

<FIG> depicts a seventh embodiment of a steam generator according to the invention.

For sake of convenience, this embodiment is described based on the embodiment of <FIG>, but similar description could be applied to other embodiments described above.

The heating element <NUM> is a tubular heating element extending over the bottom surface of the steam chamber <NUM> by defining a nested double-loop shape.

For example, the heating element <NUM> comprises a resistor to which an electrical source is supplied.

Compared to a more traditional and known tubular heating element having a U-shape (not shown), the tubular heating element with nested double-loop shape according to the invention (illustrated by transparency in dotted curved line) allows a more uniform temperature distribution to the steam chamber <NUM>.

In other words, a larger surface of the steam chamber <NUM> can be heated up evenly.

Preferably, the nested double-loop shape for the heating element <NUM> is arranged underneath the steam chamber <NUM> surface and extends over at least <NUM>% of the surface area of steam chamber <NUM> (calculated as the ratio between the projected area of the heating element to the projected area of the steam chamber surface).

This nested double-loop shape for the heating element <NUM> allows a relatively larger surface covered by the heating element.

Preferably, the linear length of the nested double-loop shape for the heating element <NUM> is in the range [<NUM>; <NUM>] mm, compared to known tubular heating element having a U-shape having a linear length in the range [<NUM>; <NUM>] mm.

Moreover, considering the limited space requirement in handheld steamer, this nested double-loop shape for the heating element <NUM> also helps to elongate the length of the heating element <NUM>, which helps to lower down the heater tube power density, thus improve the reliability and extend the life time.

<FIG> depicts a handheld steamer <NUM> implementing a steam generator <NUM> according to the invention.

The steam generator <NUM> is encased in the body of the handheld steamer <NUM>. The handheld steamer <NUM> comprises a soleplate <NUM> placed at a front end of the handheld steamer. The steam outlet(s) <NUM> pass through the soleplate <NUM> in order to spray steam over a garment <NUM>. In the illustration of <FIG>, the handheld steamer <NUM> is used to iron a garment <NUM> being in vertical position. However, the handheld steamer <NUM> could also be used to iron a garment <NUM> being in horizontal or inclined position.

The handheld steamer <NUM> comprises a water tank <NUM> connected to a water pump <NUM> via a first pipe <NUM>. The water pump <NUM> is connected via a second pipe <NUM> to the dosing hole <NUM> of the steam generator <NUM>.

When the water pump <NUM> is activated, water is dosed in the steam generator <NUM> via the dosing hole <NUM>, resulting in steam being spread over the garment <NUM>.

Preferably, the soleplate <NUM> is made of a metallic material and is connected to the steam generator <NUM>, so that the heat of the steam generator <NUM> is transferred by conduction to the soleplate <NUM> in order to improve the treatment of garment <NUM>.

Preferably, the handheld steamer <NUM> is power supplied by electrical cable <NUM>.

<FIG> depicts a stand steamer <NUM> implementing a steam generator <NUM> according to the invention.

The stand steamer <NUM> comprises a stand <NUM> in which are arranged a water supply <NUM> for supplying water to a steam chamber <NUM>, for example via an electrical water pump <NUM>. The steam chamber <NUM> is heated by heating element <NUM>. Steam generated by the steam chamber <NUM> is carried via a hose cord <NUM> to a steamer head <NUM>. The steamer head <NUM> is represented bigger than in reality, for sake of clarity. The stand <NUM> may also comprise a pole <NUM> for resting the steamer head <NUM>.

The steamer head <NUM> comprises a steam chamber <NUM> according to the invention. Steam received from the hose cord <NUM> enters the steam chamber <NUM> by the dosing hole <NUM>, and is re-heated inside the steam chamber <NUM>. Remaining water droplets that would be in this incoming flow of steam are thus evaporated in the steam chamber <NUM>. The re-heated steam then exits the steam chamber <NUM> at the steam outlets <NUM> opening in a soleplate <NUM> arranged at a front end of the steamer head <NUM>. Steam is applied on the textile (i.e. garment) <NUM> via steam outlet(s) <NUM>. The soleplate <NUM> can be heated by the heating element <NUM>. The stand steamer <NUM> has the advantage that steam exiting the steam vents <NUM> does not contain water droplets.

A control unit <NUM> allows controlling the pumping rate of pump <NUM>, the electrical power supplied to the heating elements <NUM> and <NUM>.

Claim 1:
A steam generator (<NUM>) for garment care comprising:
- a steam chamber (<NUM>) for generating steam, said steam chamber (<NUM>) extending between a front portion (FP) and a rear portion (RP),
- at least one steam outlet (<NUM>) arranged at said front portion (FP) and receiving steam from said steam chamber (<NUM>),
- a heating element (<NUM>) for heating the steam chamber (<NUM>),
- a cover (<NUM>) adapted to take a closed position for closing said steam chamber (<NUM>),
- a dosing hole (<NUM>) arranged in said cover (<NUM>), for receiving water and/or steam from outside said steam generator (<NUM>), and
arranged at proximity of said rear portion (RP) when said cover (<NUM>) is in said closed position, and characterised in that said heating element (<NUM>) is a tubular heating element extending over the surface of the steam chamber (<NUM>) by defining a nested double-loop shape.