This invention relates to a surface cleaning apparatus. More particularly, this invention relates to an apparatus for cleaning a surface such as a floor or wall which utilises a source of steam.

The use of steam cleaners for cleaning floor and other surfaces is well known. For cleaning floor surfaces, a steam cleaner typically has a cleaning head or exit aperture comprising a body able to be moved, by a user, over the surface to be cleaned, the body being adapted to carry a cleaning element of or including a fabric/textile or other material of a steam permeable absorbent nature. Steam (or very hot water) is emitted from the body and passes through the cleaning element to contact the surface being cleaned, with the effect of loosening dirt from the surface. Dirty water from condensation of the steam on the surface is absorbed by the cleaning element.

The cleaning head, to enable it to be manipulated over the surface being cleaned, may be attached to a wand and steam supplied thereto by way of a hose from a separate steam generator. Alternatively, the wand may itself be provided with a steam generator and supply of water, to form a self-contained steam cleaning device, sometimes referred to as a "stick" or "mop" type of steam cleaner.

The steam generator for such devices typically includes a water storage container (e.g. a tank which a user fills with water), an electric pump (which is controlled by a user operable switch, and could be manually operated) and a heating element(s). In use, water is fed from the tank to the heating element by the pump, where it is then heated. The resulting steam (or very hot water) then passes from the heating element towards the surface to be cleaned, to the cleaning head or exit aperture.

Typically, steam generators for such surface cleaning apparatus do not provide a pressurised source of steam. Thus, steam is emitted from the device at near to atmospheric pressure. When a user no longer requires a source of steam (e.g. they have finished cleaning), the user presses or releases the appropriate switch on the apparatus so as to disconnect the power being supplied to the electric pump. However, water which has already been fed to the heating elements(s) from the storage tank continues to be heated, at least to some degree, by any residual heat in the heating element(s) and continues to flow towards the cleaning head. This "lag" after the cessation of operation of the pump results in steam / very hot water exiting the apparatus at the cleaning head for a period of time thereafter.

According to a first aspect of the present invention, we provide a surface cleaning apparatus including:

a water storage container;

a steam generator including a heating element(s); and

a fluid passage for directing steam from the steam generator to a cleaning end of the apparatus,

wherein the apparatus includes a device for blocking the fluid passage which is moveable between blocking and unblocking positions and wherein the device moves to the unblocking position when the pressure within the fluid passage exceeds a predetermined magnitude.

According to a second aspect of the present invention, we provide a surface cleaning apparatus including:

a water storage container;

a steam generator including a heating element(s); and a fluid passage for directing steam from the steam generator to a cleaning end of the apparatus,

wherein the apparatus includes a device for blocking the fluid passage which is moveable between blocking and unblocking positions and wherein the device is biased to its blocking position.

Further features of the first and second aspects of the invention are set out in the claims appended hereto. Embodiments of the invention will now be described by way of example only with reference to the accompanying figures, of which:

FIGURE 1 is a perspective view of a surface cleaning apparatus in accordance with the present invention;

FIGURES 2 and 3 are perspective views of a housing of a valve of the surface cleaning apparatus of Figure 1 ;

FIGURES 4 and 5 are side and perspective cross-sectional views of the valve in a closed condition;

FIGURES 6 and 7 are side and perspective cross-sectional views of the valve in an open condition; FIGURE 8 is an exploded perspective view of the valve, partly in cross- section;

FIGURE 9 is a cross-sectional perspective view of the valve with the valve member thereof removed; and FIGURE 10 is a illustrative diagram of the working components of the apparatus of figure 1 .

Referring to the figures, these show a surface cleaning apparatus 10 in accordance with the present invention. The apparatus 10 has a floor cleaning head 50 which is pivotally connected to a user graspable handle 1 1 . Connected to the user graspable handle are a water storage container 12 and a housing 18 which houses a steam generator 13, a pump 14 for feeding water from the storage container 12 to the steam generator and a fluid passage connecting a steam generator output to the cleaning head 50. It should be appreciated that whilst the present embodiment includes a pump, it is not an essential element of the cleaning apparatus. In envisaged embodiments without a pump, water may pass to the steam generator under the action of gravity, for example.

Whilst figure 1 shows a surface cleaning apparatus 10 in which is embodied the present invention, it should be appreciated that the invention can be realised in other forms of surface cleaning apparatus. In particular, whilst the handle 1 1 is pivotally connected to the head 50, it need not be connected in that way (e.g. it could be rigidly connected). In addition, the water storage container 12 and the housing 18 may be supported directly on the floor cleaning head 50 rather than attached to the handle 1 1 . Furthermore, whilst the cleaning apparatus 10 has a cleaning head it may alternatively have a steam exit aperture, e.g. for spot cleaning, which may be connectable to one or more tools.

The pump 14 is fluidly connected, via a water outlet passage to the water storage container 12. An outlet from the pump 14 is fluidly connected to the steam generator, which includes a heating element (there may be more than one element) 13. As is well known in the art, the pump draws water from the water storage container 12 and feeds the water to the heating element. The heating element heats the water to at least close to boiling point, and preferably such that the water turns into steam. The hot water and/or steam exits the steam generator housing via an outlet which is connected to a fluid passage for directing steam towards the cleaning head / exit aperture of the apparatus. Positioned in the passage is a device 20 (see figures 2 to 9) for blocking the passage of fluid therethrough. The blocking device 20 is movable between blocking and unblocking positions, and this particular embodiment is provided by a spring-biased valve 26. The purpose of the valve 20 is to prevent the flow of hot water and/or steam through the passage to the cleaning head, under certain conditions, as discussed below.

Referring more specifically to figures 2 to 9, the device 20 includes first 21 and second 22 housing parts each of which includes a plurality of radially positioned apertures 23 through which fasteners can be passed to hold the first and second housing parts 21 , 22 to each other. The device has an inlet passage 24 and an outlet 25 through which steam communicates with a cleaning end of the apparatus, e.g. a steam exit aperture or a cleaning head. The inlet passage 24 and outlet 25 communicate by way of a chamber 31 in which is situated the valve 26. The valves 26 is connected to a valve stem 27 which is slidable in a cylindrical bore 30 provided in the second housing part 22. The valve 26 is biased to a closing position by a spring 28. A seal member 29 in the form of an O-ring seal is held in a circular channel in an end face of the valve 26 and provides a fluid -tightseal between an upper surface of the valve 26 and an aperture in the first housing part 21 which communicates with the inlet passage 24.

The device 20 is configured such that the valve 26 moves/is moved to its unblocking condition when a pressure within the inlet passage 24 exceeds a predetermined magnitude. In the present example, the predetermined magnitude is at or around 1 Bar. Thus, the urging force provided by the spring 28 on the valve 26 to move it to its closed position is such that when the pressure in the inlet passage 24 exceeds 1 Bar the valve is moved away from its seat such that steam in the inlet passage 24 can flow through the chamber 31 and to the outlet 25. As and when the steam pressure within the passage 24 falls below 1 Bar (i.e. equates to a force which is less than that provided by the urging spring 28), the valve 26 automatically moves/is moved to its closed position, thus preventing any steam from exiting through the outlet 25. Whilst in the present example the spring 28 is provided as a metallic spring, it could be provided in any other suitable form, e.g. a resiliently deformable member such as a rubber or rubber like material.

Whilst in the present example the device 20 is positioned in the fluid passage at or near an outlet from the steam generator, it could be positioned elsewhere in the apparatus 10. For example, the device 20 could be positioned in the fluid passage at or near an outlet from the water storage container, in the fluid passage at or near an outlet from the pump or indeed in the fluid passage at or near the cleaning end/exit aperture of the apparatus, e.g. in the cleaning head itself. It should be noted that whilst the present embodiment is configured such that the closing pressure of the spring equates to a pressure within the inlet passage 24 at or about 1 Bar, the closing force of the spring could be configured for other pressures, e.g. 1 .5 Bar. In this embodiment a pressure relief valve 60 is positioned in the passage between the pump 14 and the steam generator 13. The purpose of the PRV 60 is to provide an escape route for steam to atmosphere if the pressure within the system exceeds a predetermined maximum. In the present example the PRV is configured to operate at 3-5 Bar. The PRV could be positioned elsewhere in the apparatus. Operation of the apparatus 10 is as follows. If a user wishes to use the apparatus 10 he/she presses/actuates its power switch 80 to supply electrical power to the heating element(s) which heat up to their operational temperature. The switch 80 also effects the supply of electrical power to the pump (albeit in some cases after a period of time has passed to permit the heating element(s) to get to operational temperature). The pump feeds water from the storage container 12 to the heating element which heats the water until it turns to steam. The hot water and/or steam exits the housing containing the heating element, and passes through a passage 24 to the valve 26. The valve 26 will only move its open condition once the pressure of steam within the passage 24 exceeds the set predetermined magnitude, which in this example is 1 Bar. Once that pressure is achieved, the valve 26 moves against the force of the spring 28 to permit the steam to pass through the chamber 31 and outlet 25, to the cleaning head / exit aperture of the apparatus.

When the user decides to finish using the apparatus 10 (or indeed if a power failure to the apparatus 10 is encountered) the switch (or lack of electrical power to the apparatus 10) stops the pump from working and removes the supply of electrical power to the heating element. However, the heating elements will take some time to lose their latent heat and thus any water contained in the housing for the heating element will continue to be heated, thus providing a continuance of steam. In prior art apparatus this hot water and/or steam will continue to exit the cleaning head even when the user has decided to stop using the apparatus. However, advantageously, the configuration of the present invention, and the provision of the device 20, ensures that once the user turns the apparatus off, or electrical power supply is lost to the apparatus, very little hot water and/or steam exits the apparatus 10. This is because once the heating elements start to cool, and the pump is no longer pumping water thereto, the pressure in the passage 24 decreases quickly to less than the closing force of the spring 28. This means that shortly after the apparatus is switched off, the valve 26 automatically moves to its closed condition.

The invention is therefore highly advantageous over prior art apparatus because it ensures that little or no hot water and/or steam continues to be omitted from the cleaning end of the apparatus within a short timeframe, e.g. a few seconds, after the apparatus has been turned "off".

Whilst in the present embodiment the apparatus is an upright cleaner, it should be appreciated that embodiments are envisaged where the invention is incorporated into a handheld cleaner.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.