EP0267838A1 - Steam iron - Google Patents

Abstract

Steam is produced in a chamber (4) by falling water (16) on a base (1) in which a heating resistor (17) is embedded. An intermediate space (23) is reserved between the base (1) and a sole (19) fixed below. The steam produced goes to the fabric to be ironed through orifices (26). When the temperature of the base is high, a shutter (32) fixed to a bimetallic blade (33) is opened and steam circulates through the space (23) to escape by a clearance (25) which, by convection and conduction, completes the heat transfers from the base to the sole. For low temperatures, the shutter is closed, air settles in the space (23) and forms a screen between the sole and the base, allowing the latter to have a temperature sufficient for the production of steam. while the sole is at a relatively low temperature for ironing fragile fabrics. Use for steam ironing in a wide range of temperatures.

Description

The present invention relates to a steam iron.

In conventional steam irons, steam is produced by bringing water into contact with the upper face of a heating base, the lower face of which constitutes the ironing soleplate, or else is coated with an ironing soleplate reported.

However, when ironing fragile fabrics, the temperature of the heating base must be limited to a value which does not allow spraying on sufficient quantities of water for ironing to be significantly facilitated.

Also known from FR-A-2 279 879 is an iron in which there is provided between the heating base and the soleplate a space used for the distribution of steam to outlet orifices formed through the soleplate.

This allows the distribution of steam to the outlet orifices without having to use additional parts added to the base. According to this document, we strive to achieve the best possible thermal conduction between the base and the sole. Thus, it is to be feared that the sole is at a temperature very close to that of the base, by conduction of the bosses by which the base is supported on the sole, by conduction of the vapor present between base and sole, by convection due to the circulation of vapor, and by radiation. Thus, here again, for ironing fragile fabrics, the temperature of the heating base must be reduced to a value allowing only a very low flow rate of steam. Even if the efforts reported in this document to achieve the aforementioned good conduction had been unsuccessful, a serious problem would still arise in the sense that, for ironing at high temperature, the electrical consumption required to bring the heating base to the right temperature while producing very large amounts of steam would be disadvantageous. In addition, the components of the iron would be brought to a high temperature, detrimental to their behavior, or even excessive by the standards.

The object of the invention is thus to propose an iron capable of generating a substantial flow of steam for ironing temperatures, relatively low, and without the power necessary for ironing at high temperature and the resulting heating in the iron, don't become prohibitive.

According to the invention, the steam iron, comprising a heating base, a soleplate mounted under the heating base so as to reserve an intermediate space containing a fluid between the heating base and the soleplate, steam generating means by adduction d water in contact with an upper face of the heating base, and means for adjusting the ironing temperature, is characterized by means for, depending on the ironing temperature, modifying the nature and / or the state of the fluid present in the intermediate space, so as to relatively favor the heat transfers from the base to the sole in a range of high ironing temperatures, and has relatively slow the above-mentioned heat transfers in a range of low ironing temperatures.

Thus, during ironing at low temperature, the intermediate space constitutes a kind of heat shield between the heating base and the soleplate. Thanks to this, the heating base must have a relatively high temperature to maintain the soleplate at the moderate temperature which is desired for ironing. Thus, the water brought into contact with the upper face of the heating base vaporizes in a relatively large amount. This is how the iron according to the invention makes it possible to iron even the most fragile fabrics with steam.

When ironing at high temperature, the conditions in the intermediate space are modified so as to facilitate thermal transfers from the heating base to the soleplate. For this, it is possible, for example, to replace the fluid present at low temperature with a fluid that better conducts heat, or to set in motion in the intermediate space a hot fluid so as to carry out the additional transfers by convection. Thus, the temperature difference between the heating base and the soleplate is reduced and ironing at high temperature can be carried out without excessive power consumption and without excessive heating of the iron components.

Other features and advantages of the invention will emerge from the description below.

• - la figure 1 est une vue schématique, partiellement en coupe longitudinale, et avec arrachement, d'un fer à repasser selon l'invention, lors du repassage à basse température ;
• - la figure 2 est une vue analogue à la partie inférieure de la figure 1, lors du repassage à haute température ;
• - la figure 3 est une vue du détail III de la figure 1, à échelle agrandie;
• - la figure 4 est une vue analogue à la figure 3 mais concernant une variante ;
• - les figures 5 à 7 sont trois vues analogues à la partie inférieure de la figure 1, mais concernant des variantes de réalisation ;
• - la figure 8 est une vue analogue à la partie droite de la figure 7, mais montrant le fer en position de repos sur son talon ; et
• - la figure 9 est une vue de la base chauffante selon la ligne IX - IX de la figure 7.

In the appended drawings, given by way of nonlimiting examples:

• - Figure 1 is a schematic view, partially in longitudinal section, and with cutaway, of an iron according to the invention, during ironing at low temperature;
• - Figure 2 is a view similar to the lower part of Figure 1, during ironing at high temperature;
• - Figure 3 is a view of detail III of Figure 1, on an enlarged scale;
• - Figure 4 is a view similar to Figure 3 but relating to a variant;
• - Figures 5 to 7 are three views similar to the lower part of Figure 1, but concerning alternative embodiments;
• - Figure 8 is a view similar to the right part of Figure 7, but showing the iron in the rest position on its heel; and
• FIG. 9 is a view of the heating base along the line IX - IX of FIG. 7.

In the example shown in Figures 1 and 2, the steam iron comprises a heating base 1, made of cast aluminum, having on its upper face 2 an annular rib 3, the front part 3a and the rear part 3b are visible in the figures. The base 1 and the rib 3 thus together define a vaporization chamber 4 which is closed at the top by a sheet metal cover 6 having an opening 7 in which a plastic nozzle 8 is mounted in leaktight manner. The nozzle 8 is fitted, also in leaktight manner, onto a lower orifice 9 of a water tank 11 mounted above the vaporization chamber 4. A needle 12, controlled by a button 13 visible at the top of the iron, present on a part the length of its end activates a longitudinal groove 14 which, depending on whether it is - or not - surrounded by the lip of the nozzle 8, allows or respectively prevents the drip flow of water from the tank 11 to the vaporization chamber 4. In the situation shown in the figures, the longitudinal position of the needle 12 allows this flow and the drops of water 16 reach the upper face of the heating base 1 where they are vaporized taking into account the temperature. streak to which the heating base 1 is carried by means of the electrical resistance 17 embedded inside it during molding. The power consumed by the resistor 17 is regulated by a thermostat whose sensitive member (not shown) is in contact with the heating base 1. The temperature detected by the sensitive member is compared to a temperature displayed by means of a button selector 18.

An ironing sole 19, in stamped aluminum, is fixed to the heating base 1 so as to cover the lower face 21 and the lateral edges 22 of the latter. The mounting of the sole 19 on the base 1 is such that there is between them an intermediate space 23 extending substantially over the entire lower surface of the heating base. For this, the heating base has on its underside a series of annular bosses 24 (only one of which is shown in the figures) whose height is equal to the thickness e desired for the intermediate space 23, that is to say between 0.4 mm and 2 mm, preferably 0.6 mm. The annular bosses 24 each surround an orifice 26 passing through the base 1 inside the annular rib 3. The sole 19 has, opposite each orifice 26, an orifice 27 surrounded by an annular lip 28 which is fitted into the orifice 26 of base 1 (figure 3). During assembly, when the sole 19 is brought against the base 1, the lips 28 are substantially cylindrical. After this assembly has been carried out, the lips 28 of each orifice 27 are conically deformed so as to bear against a wall of the orifices 26 which flares conically in the direction opposite to the sole 19. This achieves a crimping binding to the base 1 the sole 19 resting on the annular bosses 24. Such a crimping method is described per se in French patent application 86 01 019 in the name of the Applicant.

Thus, the steam produced in the chamber 4 escapes through the orifices 27 of the sole 19, and through the fabrics being ironed.

The base 1 is also crossed by an opening 29 (FIG. 1) located inside the annular rib 3 and surrounded on the side opposite the sole 19 by an annular boss 31 whose free end forms a seat for a shutter 32 fixed to a free end of a bimetallic strip 33 whose other end, or anchoring end, 34 is fixed to a flange of the part 3b of the annular rib 3.

In a lower temperature range of the heating base 1, the bimetallic strip 33 presses the shutter 32 against the annular boss 31, which isolates the intermediate space 23 relative to the vaporization chamber 4 (FIG. 1).

When, depending on the position of button 18, the temperature of the heating base 1 rises to a temperature forming part of an upper, the bimetallic blade 33 curves upwards and separates the shutter 32 from the boss 31 (FIG. 2). This offers the vapor produced in the vaporization chamber 4 an additional exhaust path through the opening 29, the intermediate space 23, and an annular space 25 existing between the peripheral edge 22 of the base 1 and the peripheral rim directed towards the top of the sole 19. This path is visualized by arrows in FIG. 2.

The bimetallic strip 33 is of the type with abrupt release, that is to say that the shutter 32 suddenly changes from the open position to the closed position and vice versa when the temperature of the heating base 1 crosses a threshold of temperature determined, respectively in the direction of decrease and increase.

The iron which has just been described operates in the following manner.

When the temperature of the heating base is below the threshold, which can be chosen to be equal to approximately 200 ° C. (shutter 32 closed - FIG. 1), the intermediate space 23 is in communication with the outside and therefore contains air . The sole 19 is heated by conduction of the bosses 24 and of the crimping lips 28, by conduction of the air occupying the space 23, and by radiation emitted by the base 1 in the direction of the sole 19. Under these conditions, the temperature of the soleplate can be about 40 ° C lower than the temperature of the heating base. Thus, even if the soleplate is at an average temperature of 110 ° C corresponding to the ironing of the most fragile fabrics, the heating base 1 is maintained by the thermostat at a temperature of the order of 150 ° C allowing appreciable production of steam in the vaporization chamber 4. In the lower temperature range, the base temperature is between 150 and 200 ° C, while that of the sole is between 110 and 160 ° C.

When the thermostat is set to maintain the base at a temperature in a range from 200 to 260 ° C (shutter 32 open - Figure 2), the steam produced in the chamber 4 circulates in the intermediate space 23 instead of the air which stagnates there, and escapes between the edges of the base and the sole. This reduces the temperature difference between the base and the sole because water vapor is better conductor of heat than air, and also because the circulation of this vapor which leaves chamber 4 substantially at the temperature of the base heats up the sole by convection. In a practical case, the temperature difference between the base and the sole is only about 25 ° C, so that, for the sole, the high temperature range is between 175 and 235 ° C.

Thus, with regard to the sole, the two temperature ranges (110 to 160 ° C and 175 to 235 ° C) are not contiguous. In practice, the user does not feel this rupture in the temperature scale, because his major concern is to go from a temperature for ironing, for example wool, to a temperature for ironing cotton. In addition, unlike synthetic fibers, textile fibers which can be ironed at at least 150 ° C do not necessarily iron at a rigorous temperature, but within a temperature range, the range being wider the less the unraveling is ensured. largely by steam injection.

It is particularly emphasized that the numerical values of temperature are given only by way of illustrative examples. Indeed, the temperature of an ironing board is not homogeneous and fluctuates strongly depending on the point where the measurement is made, the instant when it is made with respect to the thermal regulation cycle, and also of the nature of the ironing room. In the numerical example that has been given, the temperatures indicated are average temperatures taken at the center of the soleplate, a point considered to be representative of the behavior of irons by standardization bodies. The temperatures recorded are those corresponding to the opening of the thermostat at a time distant from any change in setting of the thermostat setpoint.

It should also be noted that, in a conventional manner, thermostats allow the temperature of the heating base to be adjusted between ambient temperature and a maximum temperature such as 260 ° C. It is considered that sufficient production of steam is impossible when the temperature of the base is less than 150 ° C. Below this temperature, in certain embodiments, means prevent the supply of water into the vaporization chamber.

In the embodiment of Figure 4, the holes 27 of the sole 19 no longer have lips 28, and they are cylindrical and of the same diameter as the corresponding holes 26 of the base 1, also cylindrical. A sleeve 36 is fitted into each pair of corresponding orifices 26 and 27, and welded by its external face to the wall of these orifices.

In the example shown in Figure 5, a seal 37 disposed between the peripheral edge of the underside of the base 1 and the sole 19 closes the intermediate space 23 except at the rear of the iron where the underside of the base 1 is hollowed out at 38 to constitute an exhaust orifice having a sufficient section.

The advantage of this embodiment is to limit the escape of steam to the rear region of the iron, for reasons of approval of use.

According to another variant shown in FIG. 5, the sole 19 has holes 39 over its entire periphery through which the space 23 communicates with the outside, of so that the steam which has passed through the space 23 escapes through the fabric to be ironed. In this case, preferably, the seal 37 extends over the entire periphery of the underside of the base 1, including at the rear of the iron, so as to prevent any release of vapor from the periphery of the base 1 There is thus the advantage of exploiting for ironing the production of steam passing through the intermediate space 23, but on the other hand the flow rate in the intermediate space may be reduced during the ironing of certain fabrics.

In the example shown in FIG. 6, the steam escaping from the space 23 is made by the periphery of the base 1 as shown in FIG. 1. On the other hand, the steam intended for the space 23 is produced in an independent steam generator 41. This comprises a cup 42 partially closing the opening 29 and connected in one piece with the base 1 by means of bridges 43. A plastic nozzle 44 is mounted in leaktight manner in a opening of the cover 6. In addition, this nozzle is fitted in a sealed manner in the boss 31 under the cover 6, and fitted in a sealed manner in a lower opening 46 of a water tank 47 disposed above the cover 6. A valve 48, mounted in the reservoir 47 has a head 49 which cooperates with a seat constituted by the upper end of the nozzle 44, and a rod 51 which is slidably mounted through the upper wall of the reservoir 47 and which is attached to the movable end of a bimetallic blade 52 the other end of which is fixed in thermal contact with the external face of the part 3b of the rib 3 made in one piece with the base 1.

In this embodiment, when the temperature of the base 1 exceeds the threshold of for example 200 ° C., the bimetallic blade 52 with abrupt triggering raises the soup 48 and moves it away from the nozzle 44, which allows the water contained in the reservoir 47 to flow drop by drop into the orifice 29 where it strikes the cup 42, on which it evaporates in space - constituting a vaporization chamber - surrounded by the boss 31 before being discharged between the bridges 43 towards the intermediate space 23.

This makes it possible to keep the entire steam production capacity of the chamber 4 destined for the orifices 27 during ironing in the higher temperature range.

The example of FIGS. 7 and 8 will only be described with regard to its differences from that of FIG. 5.

A flexible plastic tube 53 is fitted on the one hand to the boss 31 surrounding the opening 29 and on the other hand to a neck 54 surrounding a lower opening of a reservoir 56 positioned in leaktight manner in an opening in the cover 6 A membrane 57 delimits in the reservoir 56 a lower chamber 58 filled with a liquid with very low vapor pressure and good thermal conductivity, for example a mineral or organic oil which can be used as a heat transfer fluid in the industry of ovens or solar collectors. , or a fusible salt usable for tempering metals. The membrane 57 is controlled by a rod 59 mounted to slide through an opening of a cover 61 which closes the tank 56 above and has a vent 62 for venting the tank 56 above the membrane 57. L the outer end of the rod 59 is coupled to the bimetallic blade 33.

The passage of the liquid through the tube 53 is controlled by a shutter device 63 comprising a stirrup 64 movable between the closed position shown in FIG. 7, in which its central part rests on the front side of the tube 53 and thus clamps the tube 53 against a counter-support element 66 formed integrally with the base 1 and adjacent to the rear side of the tube 53, and an open position (FIG. 8) in which the central part of the stirrup 64 is separated from the tube 53 towards the front of the iron and thus allows the tube to resume its substantially cylindrical shape allowing the passage of a fluid inside. In a manner not shown, the arms 67 of the stirrup 64 are guided to slide along the element 66 during their movement between the two aforementioned positions. At their end opposite to the central part of the stirrup 64, the arms 67, directed towards the rear, are fixed to a cup 68 which is itself fixed to the front end of a rod 69 which is mounted to slide according to the longitudinal direction of the iron. The rear end 71 of this rod protrudes from the back of the iron when the stirrup 64 is in the closed position shown in FIG. 7. On the contrary, as shown in FIG. 8, the open position of the stirrup 64 corresponds to a position for erasing the button 71 in the body 72 of the iron. A spring 73, guided between the arms 67 of the stirrup, is mounted in compression between the element 66 and the cup 68, so as to return the stirrup 64 to its closed position shown in FIG. 7.

As shown in Figure 9, the seal 37 completely surrounds the intermediate space 23 but this space no longer extends to the rear end of the iron. Indeed, the seal 37 passes behind the opening 29 so that it is at the low point of the space 23 when the iron is in the rest position on its heel as shown in Figure 8. In addition, the neck 54 of reservoir 56 is located in the region furthest forward from the bottom of reservoir 56, so that, in the rest position of FIG. 8, the opening 29 is in the high position relative to the assembly space formed by the interior of the tube 53 and of the chamber 58. Behind the seal 37 is therefore created an additional intermediate space 70.

At the anterior point of the intermediate space 23, the base 1 is traversed by a gas passage orifice 74 connected to a tube 76 whose end 77 opposite the base 1 is hermetically closed.

The iron of FIGS. 7 to 9 works as follows: when it rests by its soleplate on a surface such as an ironing piece, while the thermostat determines for the base a temperature belonging to the lower range (case of the FIG. 7), the spring 73 maintains the stirrup 64 in the position where the tube 53 is pinched and isolates the chamber 58 from the intermediate space 23. The bimetallic strip 33 determines for the rod 59 a high position in which the volume of room 58 is maximum. The intermediate space 23, the interior of the tube 76, the orifice 29 and the interior of the tube 53 below the nip produced by the stirrup 64 are filled with a gas, for example air, which limits the thermal transfers between the base 1 and the sole 19. If the user operates the thermostat adjustment button so as to enter the high temperature range, the bimetallic blade 33 exerts on the rod 59 an effort tending to reduce the volume of the chamber 58. However, this effort is in vain, and the situation does not change as long as the user does not put the iron in the position shown in FIG. 8. At this time, the button 71 is pushed back, which brings the stirrup 64 to the open position and allows the membrane 57 to push the liquid 58 into the intermediate space 23 while the gas is itself expelled through the orifice 74 to compress in the tube 76 As soon as the iron is returned to the position of figure 7, the button 71 is released and the stirrup 64 pin this tube 53, which stabilizes the situation. In the intermediate space 23, the liquid which conducts heat well greatly reduces the temperature difference between the base 1 and the sole 19.

If the thermostat button is returned to the position corresponding to a temperature in the lower range, again, it is necessary to wait for the user to put the iron in the rest position for the metal blade 33 to succeed in sucking up the liquid in the chamber 58 and let the gas contained in the tube 76 again invade the space tab 23.

The role of the shutter system 63 is to prevent the gas from rising under the membrane 57 in the iron operating position in which the liquid is in the high position relative to the gas.

According to an alternative embodiment, it can be provided that the means which, in the examples described with reference to the figures, are controlled by the bimetallic blade 33, are controlled by the position of the thermostat adjustment knob, such as 18 in the figure 1, or by a specific manual command.

According to another variant, the heating base may include bosses for supporting the sole not crossed by orifices for the passage of steam, this in order to control the heat transfer between base and sole.

Claims (15)

1. Steam iron comprising a heating base (1), a soleplate (19) mounted under the heating base (1) so as to reserve an intermediate space (23) containing a fluid between the heating base (1) and the soleplate (19), steam generating means (4, 7 to 9, 11 to 14) by supply of water (16) in contact with an upper face (2) of the heating base (1), and means (18) for regulating the ironing temperature, characterized by means (29, 31, 32; 41, 42, 44, 46 to 49; 53, 56 to 59; 72 to 74) for, depending on the ironing temperature , modify the nature and / or the state of the fluid present in the intermediate space (23), so as to relatively favor the heat transfers from the base (1) to the sole (19) in a range of high ironing temperatures , and to relatively slow down the aforementioned heat transfers in a low ironing temperature range. 2. Iron according to claim 1, characterized in that the means for modifying the nature and / or the state of the fluid in the intermediate space (23) are means (29, 31, 53, 56 to 59, 72 to 74) to selectively occupy the intermediate space (23) with two fluids of different natures. 3. Iron according to claim 2, characterized in that the fluid occupying the intermediate space (23) during ironing at a temperature belonging to the low range is a gas and the fluid occupying the intermediate space (23) ironing at a temperature belonging to the high range is a liquid. 4. Iron according to claim 3, characterized in that the liquid is chosen from a group comprising mineral oils, organic oils, fusible salts. 5. Iron according to one of claims 3 or 4, characterized in that it comprises a chamber (58) with adjustable volume, so as to be enlarged during the ironing at low temperature, in that this chamber (58) is in the low position relative to the intermediate space (23) when the iron is in the rest position erected on its heel, and in that means (63) are provided to communicate the chamber (58) and the intermediate space (23) when the iron occupies the aforementioned rest position and to interrupt this communication when the iron is in the ironing position. 6. Iron according to claim 2, characterized in that the fluid occupying the intermediate space during ironing at a temperature belonging to the low range is air and the fluid occupying the intermediate space (23) during ironing at a temperature belonging to the high range is water vapor. 7. Iron according to claim 1, characterized in that the means for modifying the nature and / or the state of the fluid occupying the intermediate space (23) comprise means (32) for adjusting the flow rate of the fluid in the intermediate space (23). 8. Iron according to claim 7, characterized in that the means for regulating the flow operate in all or nothing between an extreme position of cutting off the flow and an extreme position allowing the flow. 9. Iron according to one of claims 7 or 8, characterized in that the intermediate space (23) is connected on the one hand to a vaporization chamber (4) via a movable shutter ( 32), and secondly to exhaust means (25, 39). 10. Iron according to claim 9, characterized in that the vaporization chamber (4) is part of the steam generating means. 11. Iron according to claim 9, characterized in that the vaporization chamber (31) belongs to second steam generating means (42, 44, 46 to 49). 12. Iron according to one of claims 8 to 11, characterized in that the exhaust means comprise a slot (25) between an edge (22) of the heating base (1) and the edge of the sole ( 19). 13. Iron according to one of claims 8 to 11, characterized in that the exhaust means comprise at least one orifice (39) formed through the sole (19). 14. Iron according to one of claims 1 to 13, characterized in that the means for modifying the nature and / or the state of the fluid occupying the intermediate space (23) are controlled by means (33, 52 ) sensitive to the temperature of the heating base (1). 15. Iron according to claim 14, characterized in that the means sensitive to the temperature of the heating base (1) comprise a bimetallic blade (33, 52).

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