EP4551752A1

EP4551752A1 - Steam iron with instant steam technology

Info

Publication number: EP4551752A1
Application number: EP23731110.5A
Authority: EP
Inventors: Francesca Polti; Riccardo Turati; Gianpaolo ORTELLI; Alberto MORLACCHI
Original assignee: Polti SpA
Current assignee: Polti SpA
Priority date: 2022-05-27
Filing date: 2023-05-26
Publication date: 2025-05-14
Also published as: WO2023227766A1; EP4532817A1; WO2023227762A1

Abstract

A steam iron comprising a base comprising a water reservoir (110), a pump (130) and an ironing element. The ironing element comprises a plate (10), a central body (20), and a lid (30). The lid (30) and the central body (20) define a first steam chamber (140), the plate (10) and the central body (20) define a second steam chamber (180). The lid includes a water inlet (70). The first steam chamber (140) and the second steam chamber (180) are in fluid communication via an electrovalve (170), and the first steam chamber (140) is in fluidic connection with a pressure regulating valve (150).

Description

Steam iron with instant steam technology

Technical field of the invention

[0001]. The present invention is directed to a steam iron having the ability to deliver steam instantly with the so-called "instant steam technology".

State of the Art

[0002]. On the market, there are a wide variety of steam irons that differ from each other for the price and performance that the iron is able to guarantee. The lowest price range steam iron is the so-called drop iron or traditional iron. The traditional iron features a water tank that feeds a heated chamber where water is vaporized and steam fed to the iron plate. The main advantages of this type of steam iron are the cost-effectiveness and ease of use. On the other hand, the traditional iron has a low ironing efficiency, is not suitable for difficult garments, is not able to generate continuous steam and has a significant delay in steam delivery.

[0003]. An evolution of the traditional iron is represented by the drop iron with external tank and pump. The main difference with the traditional iron is represented by the presence of a pump that draws water from an external tank, which allows a greater autonomy of ironing, being the external tank volume considerably greater than the internal tank of the traditional iron. However, since the principle of operation is the same, this type of steam iron also presents the problem of the delay in the steam supply and the stop of the steam supply respectively when the steam supply button is pressed and released.

[0004]. These problems are not present in steam generator irons, where steam is generated in an external pressurized boiler and transported to the iron through a steam supply cable. Steam generator irons are very efficient but also cost more than traditional irons and tank irons. The advantages of steam generator irons compared to traditional irons and tank irons are mainly the wide and immediate availability of steam under pressure resulting in excellent penetration into the fabrics in vertical ironing. However, a disadvantage of steam generator irons is the heating time, since it is necessary to heat all the liquid in the boiler to be able to use the iron. [0005]. It would therefore be desirable to have an iron that combines the advantages of traditional irons and tank irons (simple operation and cost-effectiveness) to the advantages of steam generator irons (immediate availability of steam, pressure with penetration into fabrics with high ironing efficiency even vertically).

Summary of the invention [0006]. The present invention is directed to a steam iron comprising a double steam chamber, an electrovalve connecting the two steam chambers and a pressure regulation system in the first steam chamber. This technical solution allows a steam delivery at a good pressure and without delays while maintaining the simplicity and cost-effectiveness of the traditional irons.

Brief description of the figures

[0007]. Figure 1 represents an exploded view of the iron according to an embodiment of the invention composed of a plate, a central body and a cover, held together by self-forming screws.

[0008]. Figure 2 represents a view in the median longitudinal section of the iron of Figure 1. [0009]. Figure 3 represents a perspective view of the iron of Figure 1.

[0010]. Figure 4 represents a perspective view of the iron of Figure 1 where a section at the height of the electrovalve has been made.

[0011]. Figure 5 shows a top view of the central body where the water/steam path in the first chamber can be seen.

[0012]. Figure 6 shows a scheme of operation of the pressure regulating valve present in a preferred embodiment of the invention.

[0013]. Figure 7 shows a pressure vs time diagram of an iron with and without pressure control valve, with steam supply cycles.

[0014]. Figure 8 shows a pressure vs time diagram of the irons used in figure 7 diagram,

Detailed description of the invention

[0015]. Figure 1 shows an exploded view of an iron according to this invention. The section highlights a plate 10, a central body 20 and a lid 30. The three elements are preferably assembled together by self-forming screws 40 while the seal is preferably guaranteed by silicone sealants and adhesives suitable for working at high temperature.

[0016]. Figure 2 is a view in longitudinal section of the iron of figure 1. The figure shows how the design of the central body 20 and the lid 30 defines a first chamber of steam 140, while plate 10 and central body 20 define the second chamber of steam 180. The central body 20 includes a heating resistive element 50. Resistive element 50 is preferably a tubular steel armored electrical resistance using a resistive wire immersed in compressed magnesium oxide and protected by a metal tube. In one embodiment, the resistance is machined, bent in the correct geometry and drowned in the plate during the die casting process. When powered by the operating current, the resistive element 50 allows the central body 20 and plate 10 to reach the operating temperature.

[0017]. Figure 3 is a top view of the three elements (plate, central body and cover) mounted, in which there is a water pipe 131 connected to an inlet 70, a safety valve 90, and a valve 170, preferably an electrovalve.

[0018]. Figure 4 is a perspective view of the elements of Figure 3, in which a vertical section with a plane perpendicular to the axis of the iron, at the height of the steam valve, was made. From the section you can see how in this embodiment the second steam chamber has a top part 145 whose top part is defined by lid 30 and at whose bottom part is defined by plate 10. This portion of the second steam chamber allows the passage from the upper part where the first steam chamber 140 is located, to the lower part 180 defined by the central body and the plate. However, a different embodiment is possible in which valve 170 sends steam directly into the second chamber of steam 180.

[0019]. Figure 5 shows a top view of the central body, in which the path taken by the liquid/steam once it enters the first steam chamber can be understood. This labyrinth path ensures the arrival to the solenoid valve of dry steam and prevents limescale residues from getting to the solenoid valve affecting its smooth operation.

[0020]. Figure 6 shows a working scheme of the iron according to invention. The system includes a tank 110 connected to a pump 130. Between the tank and the pump there is an optional filter 120. The pump 130 feeds the first steam chamber 140 in which pressurized steam is generated which, at the opening of the (electro)valve 170 delivers steam to the second steam chamber 180 passing through the upper part of the second steam chamber 145. There is also a deaerator 190 on the first steam chamber 140. The heating element 50, present in the central body and not indicated in the diagram, is regulated by the temperature of plate 10 and therefore it is necessary that there is a second adjustment that maintains the pressure of the first steam chamber at the pre-set value. The diagram in Figure 6 therefore foresees the presence in the first chamber of steam 140 of a valve 150 of pressure regulation that opens when the pressure exceeds a fixed value (for example 3 bar) and closes when the pressure reaches a fixed value (for example 2,5 bar). The pressure regulating valve 150 is preferably connected to the tank 110 of water supply to the iron.

[0021]. When the iron user presses the steam button, the (electro)valve 170 is opened, and the steam passes from the first chamber 140 to the upper zone 145 of the second chamber of steam, which is at the same level as the first chamber of steam 140. The zone 145 is open downwards and allows steam to pass into the lower part of the second steam chamber 180 which is delimited above by the central body 20 containing the resistance 50, and below by the plate 10. Thus, the lower part of the second steam chamber 180 is also heated by the resistance 50 contained in the central body 20, which heats the upper surface of the chamber. This causes the steam in the second chamber 180 to rise in temperature so that it leaves the iron plate at a temperature that prevents condensation.

[0022]. As mentioned before, water is fed to the first steam chamber 140 via a pump 130 which, in a preferred embodiment, is activated when the valve 170, preferably an electrovalve, is open. In this way, the steam output from the first chamber is compensated by the water inlet. Preferably, the actuation button of valve 170 also actuates the pump 130.

[0023]. In a preferred embodiment, the system includes an electronic board 160 that drives both valve 170 and pump 130. The water pump 130 can be operated simultaneously by the valve, or a phase shift can be introduced between the two actions. In one embodiment, the phase shift can be introduced as a delay in the activation of the pump with respect to the valve opening. In this embodiment, pressurized steam present in the first chamber of steam 140 passes to the second chamber 180 and only later the water pump 130 activates to reintegrate steam which left the first chamber with water that, once it enters the first chamber, turns into steam. The delay between activation of the water pump 130 and opening of the valve 170 can be between 3.0 s and 0.1 s, preferably between 2.0 s and 0.2 s.

[0024]. In another embodiment, it is possible to delay the activation of valve 170 with respect to the activation of the pump. The delay in this case cannot be very high, being perceived by the user as a delay in steam supply. Thus, in this embodiment, the delay is preferably between 1.0 s and 0.1 s.

[0025]. In a steam generator iron, the boiler is equipped with an independent temperature/pressure regulation system and the iron is normally equipped with a resistance that serves to further overheat the steam and to heat the plate at the operating temperature of the same. Traditionally, the iron plate can be adjusted to different temperatures depending on the fabric, or can be used at a fixed temperature suitable for all fabrics.

[0026]. In the iron according to the invention, the first steam chamber is kept at a pressure preferably between about 2 bar and about 3 bar by a regulation system. [0027]. In the iron according to the invention, there is a temperature regulation system also connected to resistance 50. Keeping in mind that the boiling temperature of the water at 2 bar is about 120°C while at 4 bar is 143°C, it is possible to adjust the temperature to a value between 120°C and 143°C. Thus, the temperature of the central body is a correlated value, in the sense that it is not subject to regulation but is the consequence of the regulation of the pressure/temperature in the first steam chamber. It is therefore necessary that the design of the plate is such as to ensure a central body temperature around the optimal value for ironing, which is about 130 °C plus or minus 10 °C.

[0028]. As stated above, resistance 50 is connected to a temperature control system of the central body as in the state of the art irons. The pressure in the boiler is then adjusted through a pressure relief valve according to the diagram shown in Figure 6. When the pressure exceeds a fixed value, the control valve 150 opens and allows water and/or steam in chamber 140 to return to tank 110.

[0029]. The pressure regulation through the regulation valve 150 must take place at a value Pl higher than the value of pressure P2 resulting from the thermostat regulation. If Pl is too close to P2, the pressure control valve opens too often, causing a too high return of hot water and steam to the tank. If on the contrary Pl is too far from P2, the overpressure valve almost never opens and the temperature in the boiler is unstable. It has been experimentally found that preferably Pl is within the range P2+0,2 bar < Pl <P2 +1,0 bar.

[0030]. Figure 7 shows a pressure vs time diagram of a steam iron according to the invention with and without pressure control valve 150, during operation applying steam supply cycles and rest cycles. The valve 170 is kept open for 1 minute and then closed for 2 minutes. It is clear that the presence of a pressure regulation valve allows the iron to work in a narrower pressure range without decreasing steam production.

[0031] Figure 8 shows the pressure vs time diagram of the same irons used for the experiment in figure 7, this time however with valve 170 always closed. In practice, the iron is lit but not used. It can be seen that the pressure varies between a maximum value of about 2 bar, to a minimum value of 1.5 bar. This corresponds to the fact that the thermostat turns off the resistance when inside the first steam chamber a temperature of about 120° C is reached, which corresponds to a pressure P2 of 2 bar. The pressure inside the first steam chamber is lowered and once reached the value of 1.5 bar the thermostat turns on the resistance that increases the vapor pressure until it reaches again at pressure P2 of 2 bar.

Claims

1. A steam iron comprising a base comprising a water reservoir (110), a pump (130) and an ironing element comprising: a. a plate (10), b. a central body (20), and c. a lid (30); wherein the lid (30) and the central body (20) define a first steam chamber (140); the plate (10) and the central body (20) define a second steam chamber (180); and the lid includes a water inlet (70); the first steam chamber (140) and the second steam chamber (180) are in fluid communication via an electrovalve (170); and wherein the first steam chamber (140) is in fluidic connection with a pressure regulating valve (150).

2. The steam iron according to claim 1, wherein the first steam chamber (140) is a labyrinth chamber.

3. The steam iron according to any of claims 1-2, wherein the central body (20) includes a heating element (50).

4. The steam iron according to any of claims 1 to 3, in which the volume of the steam chamber (140) is between 20 ml and 250 ml.

5. The steam iron according to claim 4, wherein the volume of the steam chamber (140) is between 40 ml and 200 ml.

6. The steam iron according to any of claims 1 to 5, further comprising an electronic board that operates the electrovalve (170) and the pump (130).

7. The steam iron according to claim 6, wherein the valve (150) is set at a pressure between 2 bar and 4 bar.

8. The steam iron according to any of claims 1 to 7, wherein the steam chamber also includes a safety valve (90), which is activated upon reaching a pressure of more than 10 bar.