EP2094901A2

EP2094901A2 - A device for supplying superheated water

Info

Publication number: EP2094901A2
Application number: EP07849447A
Authority: EP
Inventors: Jan G. E. PIETERS; Roland Van Straaten; Martin Hommes
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2006-12-18
Filing date: 2007-12-12
Publication date: 2009-09-02
Also published as: BRPI0721351A2; RU2009127790A; JP2010512905A; WO2008075255A3; WO2008075255A2; CN101563496A; CN101563496B; US20100011629A1; EP1944404A1

Abstract

A device (1) for supplying superheated water, comprising a container (3) for containing water, and a heating element (5) for heating water in the container to a superheated state. During use the water in the container is superheated, by the heating element typically 120 to 140 0C. The pressure in the container is suppressing the evaporation of the water. If this superheated water is released from the container via a water outlet (7) for letting out superheated water, it evaporates due to decrease of pressure when leaving the container. As a result the amount of steam generated by the device is increased. The invention is further related to a domestic appliance comprising a device for supplying superheated water.

Description

A device for supplying superheated water

FIELD OF THE INVENTION

The invention is related to a device for supplying superheated water, comprising a container for containing water, and a heating element for heating water in the container to a superheated state. The invention is further related to a domestic appliance comprising a device for supplying superheated water.

DESCRIPTION OF THE PRIOR ART

A device for supplying superheated water is known in practice. A heating element provides heat to water present in a container, such that the water is superheated, typically 120 to 140 ⁰C. Usually while generating superheated water the container is closed; this means that the pressure in the container is suppressing the evaporation of the water. In practice such a device is also referred to as a pressure cooker.

The device for supplying superheated water comprises the heating element having a power Pl and the container for containing water. During operation the heating element heats the water in the container thereby generating superheated water and steam. Due to gravity water is present in what is usually called the lower part of the container and steam is present in the upper part of the container. In known devices an opening is present in the upper part for letting out steam. The opening is usually provided with an electro valve to control the amount of steam that is let out of the container. The amount of steam available in the container depends on the power Pl. The higher the power Pl, the more steam available in the container and therefore the higher the steam rate. In domestic appliances however, the power Pl is limited to the power available from a power/wall socket. As a result the amount of steam available in the container is limited to a certain maximum corresponding to Pl.

SUMMARY OF THE INVENTION

It is an object of the invention to improve the device of the kind mentioned in the opening paragraph in order to increase the amount of steam generated by the device. This object is achieved by a device for supplying superheated water, comprising a water outlet for letting out superheated water. The device according to the invention is defined in claim 1.

Superheating (sometimes referred to as boiling retardation, boiling delay, or defervescence) is the phenomenon in which a liquid is heated to a temperature higher than its standard boiling point, without actually boiling. The term superheated water refers to liquid water under pressure between 100⁰C and its critical temperature, 374⁰C. During use the water in the container is superheated, by the heating element typically to 120 - 140 ⁰C. The pressure in the container is suppressing the evaporation of the water. If this superheated water is released from the container via the water outlet for letting out superheated water, it evaporates due to decrease of pressure when leaving the container. In practice the water outlet is at least partially below the water level during use. Experiments have shown that using the device according to claim 1 leads to a larger amount of steam than usually is obtained with steam generated in the container using power Pl and released from the container via the opening in the upper part of the container.

This way the object of the invention is achieved.

Steam in this paper may be dry steam or wet steam depending on the amount of water present.

In a preferred embodiment of the device according to the invention the container is provided with a water zone and a steam zone, the water outlet being located at least partially in the water zone.

The water zone is the zone in the container where during use water is present, the steam zone is the zone in the container where during use steam is present.

The water outlet may be a water discharge opening in a wall of the container.

During use the water outlet is in contact with water present in the container.

The water outlet opening may be present at the -during use- bottom of the container. As water will flow to the lowest point this is an easy way to ensure that water in the container is present at the water outlet and, if at superheated temperature, available for generating steam.

Alternatively the water outlet may be present as an opening in a side wall of the container, preferably near the bottom. During use the water outlet is -at least partly- below the water surface.

In another alternative the device comprises a water transfer path, such as a hose, a pipe or a tube. The water transfer path connects an opening in the wall of the container, a so-called wall opening- with water present in the water zone. In this alternative the water outlet is an opening in the pipe or tube, whereby the water outlet is located in the water zone. Practically it may be that one end of the tube is hanging in the water, while the other end is connected to the wall opening. Such a set up may be practical in case, for instance for construction purposes, the wall opening is located close to the top or in the top of the container, while the water is at a level such that it is not in contact with the wall opening.

In an embodiment according to the invention the water outlet is connected to an evaporation space for evaporating superheated water. The evaporation space may for example be an evaporation chamber or a pipe. The pipe may have an increased radius to facilitate evaporation of the superheated water.

In an embodiment of the device according to the invention, the device comprises a water inlet for letting water into the container, the water inlet being located in the steam zone. The steam is the zone is in the upper or higher part of the container during use. If the water inlet is located in the steam zone water upon entrance of the container water will fall under the force of gravity into the water zone. This way the amount of water in the container may easily be replenished.

In an embodiment of the device according to the invention, the water outlet comprises a valve having an open and a closed position. In the open position superheated water will be let out for generating steam, after sufficient superheated water has been let out the valve will be closed. Usually the valve will be controlled by a controller for controlling the position of the valve in dependence of user input. For instance if the user presses a steam- shot trigger the valve is set to the open position generating a shot of steam. Alternatively the user may give a steam- flow trigger that results in a prolonged opening of the valve and thus of a prolonged expelling superheated water.

If the water outlet is partly above the water surface, steam generated inside the container will escape together with the superheated water if the valve is in its open position. If the water outlet is completely below the water surface, a larger amount of water will be expelled from the container if the valve is opened. As a result a larger amount of steam is generated from evaporating superheated water if the water outlet is complete below the water surface during use.

The container may have a steam outlet opening located in the steam zone. Such a steam outlet may be used for letting out steam generated inside the container. This is a usual configuration in known boilers or steam generators. This way a regular flow of steam is obtained. The steam generated from evaporating superheated water may be used to give an additional shot of steam on top of the regular flow of steam.

In a preferred embodiment of the device according to the invention, the device further comprises a steam outlet located in the steam zone, the water outlet being in communication with a first transfer path and the steam outlet being in communication with a second transfer path.

The water outlet for generating steam form superheated water is connected to the first transfer path, such as a first hose or a first pipe.

An electro valve, further also called first electro valve, may be situated at the outside of the container at the location of the water outlet between the water outlet and the transfer path. Such electro valve is used for controlling the release of superheated water from the container.

The steam outlet is located in the steam zone of the container and is arranged for letting out the regular flow of steam which is present in the container. A second electro valve may be provided at the steam outlet for controlling the release of steam from the container. The steam outlet is connected to the second transfer path, such as a second hose or a second pipe.

This way each transfer path may be used to provide steam at a different region during use. For instance in combination with an iron having a soleplate, each transfer path may be used to provide steam at a different region in the sole plate. This provides flexibility in the design. For instance steam generated from superheated water may, via the first transfer path, be transferred to a front zone located at the -so called- tip of the iron. The steam obtained from the steam zone in the container may, via the second transfer path, be transferred to a back zone in the sole plate located closer to the -so called- heel of the iron.

In another embodiment the first and second transfer path are joined to a mutual transfer path. By joining the first and second transfer path to a mutual steam transfer path the regular steam and steam generated from evaporating superheated water outside the container may be combined to one stream of steam or may be used alternating. This way operational flexibility of the device according to the invention is obtained.

The domestic appliance according to the invention comprises the device according to the invention.

The steam generated by evaporation of superheated water outside the container may be used for instance to iron a piece of garment, to steam curtains, to steam milk and generate foamed milk, to make coffee such as espresso or to clean at least a part of a surface to remove for instance calc or dirt or a combination thereof.

In a practical application the device for supplying superheated water may be part of a boiler ironing system.

The boiler ironing system comprises a steam iron and the device for supplying superheated water.

In an embodiment of the domestic appliance, the domestic appliance is a garment care system such as a so-called boiler ironing system. The boiler ironing system comprises the device according to the invention and further comprises an steam iron having a sole plate opening for letting out steam, the system having a communication unit for transporting an output of superheated water from the water outlet to the soleplate opening. In practice the output of superheated water close to the water outlet will comprise steam and some water. Further along the communication unit, more water may evaporate and the ratio steam/water may increase.

The device for supplying superheated water comprises the heating element having the power Pl and the container for containing water. During operation the heating element heats the water in the container thereby generating steam. The container is usually provided with an electro valve through which steam can be transferred to the iron. The steam iron comprises a sole plate with a sole plate surface, a steam chamber and a second heating element having a power P2 for heating the steam chamber and the sole plate surface. The sole plate has at least one sole plate opening located in the sole plate surface for letting out steam to a piece of garment. Usually, a hose is provided between the electro valve and the steam chamber through which hose steam can be transported to the iron.

In practice if the electro valve is triggered, it opens and the output of super heated water, which may also be referred to as yield of super heated water, travels from the container, also referred to as boiler, to the iron. Finally, steam leaves the iron through the sole plate openings in the sole plate of the iron.

The amount of steam available for ironing i.e. leaving the iron per unit time is called the steam rate. The steam rate depends on the amount of steam available in the boiler.

The higher the power Pl, the higher the steam rate.

The heating element for heating the soleplate and the steam chamber in the iron needs a certain minimum of power: P2(min) for converting water droplets into steam and for heating the soleplate. Because the total power of the system (Ptotal = P1+P2) is limited to the power available from a power source, particularly a power/wall socket, Pl is limited to a certain maximum (Pl (max) = Ptotal - P2(min)). As a result the amount of steam available in the boiler is limited to a certain maximum corresponding to Pl.

The device according to the inventions increases the amount of steam available while keeping P2 at least at P2(min). By applying the device according to the invention an increased amount of steam is available for ironing.

The device may be used in a domestic appliance or for instance in a steam cleaner.

The steam cleaner may be used to clean a surface.

The device may be used to clean a surface in the domestic appliance, such as to remove dirt and / or calc from at least a part of the surface of inside of the iron, such as at least a part of the steam chamber and/or the steam channels.

In an embodiment of the domestic appliance, the domestic appliance is a garment care system further comprising a steamer having a steamer opening for letting out steam, the system having a communication unit for transporting an output of superheated water from the water outlet to the steamer opening.

Alternatively the domestic appliance may be an espresso apparatus or a coffeemaker or the like.

The invention further relates to a method for generating steam using a device for supplying superheated water, comprising

- a container for containing water,

- a heating element for heating water in the container to a superheated state, and

- a water outlet for letting out superheated water, wherein the water outlet comprises a valve having an open and a closed position, the method comprising the steps of: providing a water level in the container such that the water outlet is at least partially below the water level and heating water to a superheated state, after that using the valve in the open position.

The method for generating steam according to the invention may be used for generating for instance a flow of steam or a shot of steam. The shot of steam may be generated by applying the above mentioned steps wherein the valve is used in the open position for a short period of time, typically in a range of 0.1 - 3 seconds. In practice the shot of steam may be used to remove wrinkles from a heavily wrinkled piece of garment, for instance during ironing.

The method may be executed using the boiler ironing system or the garment care system according to the invention.

In practice the container, also referred to as boiler, is usually used in combination with a water tank, which is separately arranged from the boiler, and a pump for pumping water from the water reservoir to the container. The boiler comprises the heating plate connected to the heating element. The electro valve is arranged to open to let steam be released via the steam delivery hose. The boiler usually further comprises a pressure sensor to measure the pressure inside the boiler, a water level sensor and a safety valve that opens if the pressure inside the boiler is too high in relation to a reference value. To fill the container, water is pumped by a water pump from the water tank to the boiler. A de-airing valve may be present to let air out of the water. The water level sensor activates the water pump to pump water and thus set the water level inside the boiler.

There are different ways of determining the water level inside the boiler, examples are:

Measure the temperature at a wall of the container, this may be done electronically or using a bi-metal set at a certain temperature, and provide a threshold temperature at which new water is pumped into the boiler.

Provide an electrode inside the container from the top down to just above the bottom, without touching the bottom. The electrode determines the water level and gives a signal to a water level controller. The water level controller compares the signal to a set value corresponding to the location of the water outlet. If the water level is lowered to a value close to the location of the water outlet the boiler is filled with new water.

Before the valve is opened to generate steam from superheated water, two conditions have to be fulfilled: the water level has to be high enough, this means the water outlet has to be at least partially below the water level and the water has to be in the superheated state. If these two conditions are fulfilled and the valve connected to the water outlet is opened, the superheated water will be let out to evaporate and thus steam is obtained.

The invention also relates to any possible combination of features or subject matter as claimed in the claims.

The invention will now be exemplarily described with reference to the accompanying drawings. In principle all aspects can be combined. BRIEF DESCRIPTON OF DRAWINGS

Figure 1 schematically depicts a first embodiment of the device according to the invention.

Figure 2 schematically depicts a second embodiment of the device according to the invention.

Figure 3 schematically depicts a third embodiment of the device according to the invention.

Figure 4 schematically depicts an embodiment of the domestic appliance according to the invention.

DETAILED DESCRIPTON OF DRAWINGS

In figure 1 a first embodiment of the device 1 according to the invention is schematically depicted. The device 1 comprises a container 3 for containing water having a heating plate 6 comprising a heating element (5), and a water outlet 7 for letting out superheated water. An electro valve 9 having an open and a closed position, is connected to the water outlet 7. The water outlet 7 is located at the bottom of the container. The container 3 further has a water inlet 11 to facilitate filling the container with water. The inlet 11 is provided with a pump 13, for pumping water into the container. The container 3 depicted in figure 1 comprises water. The part of the container 3 that comprises water is called a water zone 17. The zone above the water level 16 is referred to as a steam zone 15. The water outlet 7 is located in the water zone 17, i.e. it is located at least partially below the water surface 16.

The heating element 5 heats the water in the container to a superheated state. During heating the electro valve. 9 is in closed position. After the water reaches its superheated state, the electro valve 9 may be triggered to its open position and as a result superheated water will be let out of the container 3 via the water outlet 7. The water will at least partially expand at an evaporation space outside the container 3, a suitable location for the evaporation space is schematically indicated by nr 4.

The evaporation space may for example be an evaporation chamber or a widened pipe to facilitate evaporation of the superheated water.

In figure 2 a second embodiment of the device 100 according to the invention is schematically depicted. The device 100 comprises a container 103 for containing water having a heating plate 106 comprising a heating element 105 and a water outlet 107 for letting out superheated water. An electro valve 109 having an open and a closed position, is connected to the water outlet 107. The container depicted in figure 2 comprises water. The part of the container that comprises water is called a water zone 117. The zone above the water level is referred to as a steam zone 115. A water transfer path 108, such as a hose, a pipe or a tube, connects a sidewall opening 102 in the container 103 to water present in the water zone 117. This way an end of the water transfer path 108 forms the water outlet opening 107.

The heating element 105 heats the water in the container to a superheated state. During heating the container is closed, the electro valve 109 is in its closed position. After the water reaches its superheated state, the electro valve 109 may be triggered to its open position and as a result superheated water will be let out of the container via the water outlet. The water will expand at an evaporation space outside the container, a suitable location for the evaporation space is schematically indicated by nr 104. The evaporation space 104 may for example be an evaporation chamber, a pipe or a tube. In this set-up water leaves the container 103 at the sidewall opening 102 located in the steam zone 115 of the container. The sidewall opening in this embodiment is located away from the heating element, which is located at the bottom. The skilled person may choose alternative arrangements.

The container 103 may also comprise a fill opening for filling and/ or refilling the container with water.

In figure 3 the third embodiment of the device 200 according to the invention is schematically depicted. The device 200 comprises a container 203 for containing water having a heating element 205 connected to a heating plate 206, and a water outlet 207 for letting out superheated water. A first electro valve 209 having an open and a closed position, is connected to the water outlet 207. The container 203 depicted in figure 3 comprises water. The part of the container that comprises water is called a water zone 217. The zone above the water level is referred to as a steam zone 215. The water outlet 207 is located in the water zone 217. The water outlet 207 is located at the lower half of a side wall of the container 203. The container 203 further has a water inlet 211 to facilitate filling the container with water. The inlet is provided with a pump 213. A hose 221 connects the pump 213 to a water tank 223. The water tank may be attached to a stand comprising the device 200 also referred to as boiler or steam generator. In many cases, the water tank 223 is removably arranged, so that a user of the device comprising the water tank is capable of bringing the water tank to a tap or the like in order to fill the water tank, without having to move the entire device. The water may be pumped by the pump 213 via the hose 221 under command of a pump signal from an electric control device (not shown). The heating element 205 heats the water in the container 203 to a superheated state. The container is further provided with a steam outlet 227 located in the steam zone 215. A second electro valve 229 is in communication with the steam outlet 227. The second electro valve 229 has an open and a closed position for allowing or preventing, respectively, steam generated inside the container to leave the container. Typically the pressure in the container during use is in a range of 2-5 bar.

During generation of superheated water the first and second electro valve 209, 229 are in closed position while the heating element heats the water. After the water reaches its superheated state, the first electro valve 209 may be triggered by the user or by a control unit (not shown) to its open position. As a result superheated water will be let out of the container 203 via the water outlet 207. The water will expand in an evaporation space outside the container 203 and thus steam is generated outside the container. The evaporation space in this embodiment is a pipe. The pipe may have an increased radius to facilitate evaporation of the superheated water. The pipe also functions as a first transfer path 210 to transfer the steam generated by the expanded superheated water to a place of use.

The steam generated inside the boiler 203 may leave the boiler 203 via the steam outlet 227. The steam outlet 227 is in communication with a second transfer path 230. In practice the second path 230 may be a tube, a pipe or a hose that allows for transfer of steam from the device toward a place where it may used.

Accordingly both transfer paths 210, 230 function to transport steam to a location where it can be advantageously applied, such as the sole plate of a steam iron.

It is important that the water outlet directly communicates with the water zone, while the steam outlet directly communicates to the steam zone.

The first transfer path 210 and the second transfer 230 path are joined via a joining piece 240 to a mutual transfer path 242. This provides the flexibility of supplying steam generated inside the container, steam generated via evaporation of superheated water or a combination thereof. In case such a device is applied in combination with an iron steam generated inside the container and obtained via the steam outlet may be used for regular steam ironing whereas the steam generated by evaporation of superheated water may be used to give an additional shot of steam.

By combining the two steam paths into the mutual path no further technical measures have to be taken from the side of the iron to handle both steam sources. The iron may simply be connected to the mutual transfer path to benefit from the invention. Alternatively the mutual path 240 is absent and both transfer paths 210 and 230 are individually connected to the iron. This way each transfer path may be used to provide steam at a different region in the sole plate. This provides flexibility in the design. For instance steam generated from superheated water may, via the first transfer path, be transferred to sole plate openings in a front zone located at the -so called- tip of the iron. The steam obtained from the steam zone in the container may, via the second transfer path, be transferred to sole plate openings in a back zone in the sole plate located closer to the -so called- heel of the iron.

In figure 4 an embodiment of a domestic appliance according to the invention is schematically depicted. The domestic appliance comprises the device 300 according to the invention and an iron 320. The device and iron are connected via a communication unit, also referred to as transfer path, 310 such as a hose or a tube.

The iron 320 has a body 322 and a soleplate 324 connected to the body. Usually, the body has the form of a housing having a handle and accommodating several components of the iron. The soleplate comprises a steam chamber 330 having steam outlets 328, which outlets end up in the sole plate contact surface 326. A second heating element 332 having a power P2 is present in the soleplate for heating the steam chamber and the sole plate surface.

The device 300 comprises a container 303 for containing water having a heating element 305 such as a heating plate, and a water outlet 307 for letting out superheated water. An electro valve 309 having an open and a closed position, is connected to the water outlet 307. The water outlet 307 is located at a side wall in the vicinity of the bottom of the container 303. The container 303 may further have a water inlet (not shown) to facilitate filling the container with water. The container depicted in figure 4 comprises water. The part of the container that comprises water is called a water zone 317. The zone above the water level is referred to as a steam zone 315. The water outlet 307 is located in the water zone 317.

The heating element 305 heats the water in the container to a superheated state. After the water reaches its superheated state, the first electro valve 309 may be triggered to its open position and as a result superheated water will be let out of the container via the water outlet 307. The water will expand at an evaporation space 304 outside the container, a suitable location for the evaporation space is schematically indicated by nr 304. The steam generated via evaporation of superheated steam travels through the transfer path 310 to the iron 320. The transfer path 310 is connected to the steam chamber 330 of the iron 320 via an iron transfer path 312. The steam reaches the steam outlet opening 328 or openings provided in the sole plate of the iron via the steam chamber 330. The steam chamber is typically heated by the second heating element 332 present in the sole plate 324, but an auxiliary heating element may instead be provided. The steam chamber may function as evaporation space.

In practice when the electro valve 309 is triggered, it opens and steam travels from the container 303, also referred to as boiler, to the iron 320. Finally, the steam leaves the iron through the sole plate openings 328. The construction from fig. 3 having a first, a second, and a mutual transfer path can also advantageously be applied in the domestic appliance shown in fig. 4.

While the invention has been illustrated and described in detail in the drawings and foregoing description, illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the description and the claims. The word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. Any reference sign in the Claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A device (1, 100, 200, 300) for supplying superheated water, comprising a container (3, 103, 203, 303) for containing water, a heating element (5, 105, 205, 305) for heating water in the container to a superheated state, and a water outlet (7, 107, 207, 307) for letting out superheated water.

2. A device according to claim 1, wherein the container is provided with a water zone (17, 117, 217, 317) and a steam zone (15,115, 215, 315), the water outlet (7, 107, 207, 307) being located in the water zone.

3. A device according to claim 1, wherein the water outlet is connected to an evaporation space (210) for evaporating superheated water.

4. A device according to claim 1, wherein the device comprises a water inlet

(11,211) for letting water into the container (3, 103, 203, 303), the water inlet being located in the steam zone (15,115, 215, 315).

5. A device according to claim 1, wherein the water outlet comprises a valve (9, 109, 209, 309) having an open and a closed position.

6. A device according to claim 1, wherein the device further comprises a steam outlet (227) located in the steam zone, the water outlet (7, 107, 207, 307) being in communication with a first transfer path (210, 310) and the steam outlet being in communication with a second transfer path (230).

7. A device according to claim 6, wherein the first and second transfer path are joined to a mutual transfer path (242).

8. A domestic appliance comprising a device (1, 100, 200, 300) according to any one of the claims 1-7.

9. A domestic appliance according to claim 8, wherein the domestic appliance is a boiler ironing system further comprising an iron (320) having a sole plate opening (328) for letting out steam, the system having a communication unit (310) for transporting an output of superheated water from the water outlet (307) to the sole plate opening.

10. A domestic appliance according to claim 9, wherein the domestic appliance is a garment care system further comprising a steamer having a steamer opening for letting out steam, the system having a communication unit for transporting an output of superheated water from the water outlet to the steamer opening.

11. A method for generating steam using a device (1, 100, 200, 300) for supplying superheated water, comprising a container (3, 103, 203, 303) for containing water, a heating element (5, 105, 205, 305) for heating water in the container to a superheated state, and a water outlet (7, 107, 207, 307) for letting out superheated water wherein the water outlet comprises a valve (9, 109, 209, 309) having an open and a closed position, the method comprising the steps of providing a water level in the container such that the water outlet is at least partially below the water level and heating water to a superheated state, after that using the valve in the open position