WO2003072147A2

WO2003072147A2 - Steam steriliser

Info

Publication number: WO2003072147A2
Application number: PCT/GB2003/000827
Authority: WO
Inventors: David Gooch
Original assignee: Top-Box Limited
Priority date: 2002-02-27
Filing date: 2003-02-27
Publication date: 2003-09-04
Also published as: WO2003072147A3; GB0204594D0; AU2003215726A1

Abstract

A steam steriliser (1) comprising a sterilising compartment (3) including a water reservoir, a water heating element (5) for producing steam and a sterilising station (7) for receiving items (9) to be sterilised, and in the upper area of the sterilising compartment, a condenser (11) for condensing steam rising to the ceiling of the sterilising compartment. A steam steriliser comprising a sterilising compartment including an openable door (21), the door being coupled to a door opened sensor (23), with steam generation means (5) coupled to electronic control means (25) including a timer, capable of operating in an automatic mode such that when the contents of the steriliser are no longer sterile, due to the period elapsed since sterilisation or the door (21) having been opened, the electronic control means (25) automatically initiates a further sterilisation cycle.

Description

Steam Steriliser Field of the Invention

The present invention relates to a steam steriliser applicable with particular advantage to sterilising baby equipment.

In the following specification the term 'baby equipment' will be used to mean any requisites for a baby, usually feeding equipment, which need to be sterilised. Examples are bottles, teats, spoons, dummies, and breast pumps. Sterilisation is intended to supplement washing to help reduce the risk of infection from bacterial growth.

There are many sterilisers currently on the market - these need to be quick and easy to use - and typically portable. There are three commonly used methods for sterilising baby equipment. The first is chemical sterilisation, which is carried out in a cold water solution containing a dissolved sterilising tablet. Items are submerged in the solution for at least 30 minutes. A fresh solution has to be made every 24 hours. With this method a tank of sterilising equipment is a permanent feature of the home and represents a continuous method. The second method is microwave steam sterilisation. Here all items are placed within an open container or tray. A small reservoir of water is placed adjacent the items on the tray. The complete unit is heated within a microwave oven such that the resulting steam is produced over a suitable period of time to sterilise the contents of the tray. This method depends upon the availability of a microwave oven.

The third method is electric steam sterilisation where all items are placed within a container. A small reservoir of water below the items is heated by an electric heating element such that the resulting steam is produced over a suitable period of time to sterilise the contents of the container. Typically in such a steriliser the heating elements are difficult to access and clean. This can lead to a build up of debris and water deposits which creates a potential for germ and bacterial growth. Removal of items immediately after steam sterilisation can be hazardous and inconvenient. This is due to the excessive amount of steam released by the opening of the container; the outer temperature of the container can reach 90°C and the items can be too hot to touch.

Consumer research has found that many parents steam sterilise items overnight or once when the container is full. Some items therefore tend to be left for more than 2 hours before use after which they are not deemed to be sterile. Also opening the sterilizer to remove one item renders all other items contained therein non sterile.

Summary of the Invention

According to a first aspect of the invention there is provided a steam steriliser comprising a sterilising compartment including a water reservoir, a water heating element for producing steam and a sterilising station for receiving items to be sterilised, and in the upper area of the sterilising compartment, a condenser for condensing steam rising to the ceiling of the sterilising compartment.

Thus steam condenses and then returns to the water reservoir. Preferably the inner surface of the sterilising compartment is arranged such that condensed water runs down the walls of the compartment to return to the reservoir, thus helping to cool the walls of the compartment.

Because the steam condenses, when the items are to be removed , there will be a reduced release of steam. As will be apparent to the skilled addressee of the specification, there are many types of heat exchanger which could be used as the condenser. However it is preferred that the condenser comprises a condensing element of high conductance material having a pathway for ambient air defined on its upper surface, and a fan for drawing ambient air across the surface. The use of ambient air cools the upper area of the steriliser.

In this case, preferably the fan may be operated at different speeds, one for use during sterilisation and a second higher speed for cooling the compartment and its contents after sterilisation. This means that the sterilised items can be handled soon after sterilisation.

Preferably the steriliser includes a timer for controlling the time of sterilisation, and for timing the period from sterilisation for indicating if the contents are still sterile.

Also given that the contents will no longer be sterile once the door to the compartment has been opened, preferably the steriliser includes a door coupled to a door open sensor so that an indication can be made that the door has been opened.

According to a second aspect of the invention there is provided a steam steriliser comprising a sterilising compartment including an openable door, the door being coupled to a door opened sensor , with steam generation means coupled to electronic control means including a timer, capable of operating in an automatic mode such that when the contents of the steriliser are no longer sterile, due to the period elapsed since sterilisation or the door having been opened, the electronic control means automatically initiates a further sterilisation cycle. Typically the period which elapses since sterilisation has to be less than 2 hours in order to retain the sterility of the contents.

Preferably the steriliser also includes a thermometer to measure the temperature of sterisilisation. If this is incorrect, the sterilisation can be repeated.

Preferably the electronic control means also includes a user interface which allows the user to time when sterilisation to occur to delay the start of the cycle so that the sterilisation is within 2 hours of intended use of the contents.

Replenishing of the water reservoir is optimised by the condensing effect and the form of the inner walls of the sterilising compartment which directs the water back to the base rather than allow steam to escape from the container.

Preferably the sterilising compartment includes a pressure release system, typically in the form of a relief valve to ensure pressure build up within the second compartment remains within safe levels.

Preferably the steriliser includes an inlet for replenishing the water reservoir when it falls below a threshold level. Preferably the water reservoir includes a water level indicator for this purpose.

Preferably the steriliser includes an easily accessible and removable heating element to facilitate cleaning of the entire steriliser and thus reduce the risk of bacterial build up.

Preferably the door is a fold down side door to allow ready removal of the sterilised items. The sterilisation station may just comprise a foraminous floor lying above a water reservoir onto which the items to be sterilised may be placed. Conveniently however the steriliser includes one or more trays mountable within the sterilising compartment for receiving the articles.

Preferably the steriliser also includes a concealable /slidable cable tidy to reduce the amount of excess cable lying adjacent the steriliser.

Preferably the steriliser includes a carry handle at or around its top to assist portability.

The container may have clear walls which may be double skinned with two walls separated by an air gap to provide an insulating volume of air so that the outer walls of the container are safe to touch during and immediately after sterilisation. The air gap may also incorporate a water channel for the condensed water to return to the reservoir.

It will be apparent that the shape of the container and its upper area may be designed to ensure maximum efficiency of the condenser and to improve flow of condensed water back into the reservoir. The choice of such design will be readily apparent to the skilled addressee of the specification.

The heating element and control electronics may be powered by mains electricity but for portability preferably it includes an auxiliary battery power.

Brief Description of the Drawings

A steam steriliser in accordance with both aspects of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a schematic section through a steam steriliser shown containing 3 bottles;

Figure 2 is a perspective view of the steam steriliser; Figure 3 is a block diagram illustrating the control and user interface of the steam steriliser; and ,

Figure 4 is a flow chart illustrating the automatic operation of the steriliser.

Description of the Preferred Embodiment

A steam steriliser 1 comprises a sterilising compartment 3 including a water reservoir ( not shown) , a water heating element 5 for producing steam and a sterilising station 7 for receiving items 9 to be sterilised, and in the upper area of the sterilising compartment 3 a condenser 11 for condensing steam rising to the ceiling of the sterilising compartment 9.

The condenser 11 comprises a condensing element 13 of high heat conductance material having a pathway 15 for ambient air defined on its upper surface 17, and a fan 19 for drawing air across the surface 17.

The fan can be operated at two speeds, a first sterilising speed and a second faster cooling speed to allow rapid cooling of the steriliser and its contents after sterilisation. The system is arranged such that the cooling cycle initiates immediately after sterilisation.

The steriliser 1 also comprises a door 21 which is openable and coupled to a door opened sensor 23. The heater 5 comprising the steam generation means is coupled to electronic control means 25 which includes a timer (not shown) capable of operating in an automatic mode such that when the contents of the steriliser are no longer sterile, due to the period elapsed since sterilisation or the door 21 having been opened, the electronic control means 25 automatically initiates a further sterilisation cycle.

The steriliser 1 includes a user interface 27 which comprises a series of user control buttons 29 and a display 31. Control electronics 25 is coupled to the user control buttons 29, display 31, the heater 5, the door open sensor 23 and a temperature sensor 33. It is also coupled to fan 19 to control switch it on and off and to control its speed.

The control electronics 25 include a timer (not shown) which allows the time of heating to be monitored and controlled. In order to prevent the use of a non sterile item, the lid open sensor 23 senses when the lid has been opened to allow a message to be displayed on the display means 31 that the contents are now non sterile. Similarly after 2 hours after completion of sterilisation a similar message is displayed.

The sterilization cycle reinitiates after 2 hours automatically or after the lid has been opened and then reclosed. The temperature sensor 33 senses whether the sterilisation has been carried out at the correct temperature and indicates whether resterilisation is required.

In order for the items to be sterile when required, the user can enter a delay time within 2 hours of the required usage. This will ensure that the contents are still sterile for use. These steps are illustrated in the flow chart of figure 4.

The surface of the condensing element 13 is domed and shaped to maximize the collection and flow of condensed water from the condenser surface to the walls of the compartment for return to the water reservoir. At the side of the compartment 3 is water inlet 35 for replenishing the water reservoir when it falls below a threshold level. A water level indicator 37 in the form of a window indicates when replenishment is required.

A pressure relief valve provides a pressure release system to avoid unwanted pressure build up in the sterilising compartment.

The heating element 5 is easily accessible and removable for easy cleaning to prevent the risk of bacterial build up.

The door 21 is a fold down side door to allow ready removal of the sterilised items. The sterilisation station 7 comprises a slide in basket, which is perforate to allow easy movement of the steam around its contents.

A carry handle 41 is included at the top of the steriliser to assist portability

Claims

1. A steam steriliser comprising a sterilising compartment including a water reservoir, a water heating element for producing steam and a sterilising station for receiving items to be sterilised, and in the upper area of the sterilising compartment, a condenser for condensing steam rising to the ceiling of the sterilising compartment.

2. A steam steriliser according to Claim 1 , in which the inner surface of the sterilising compartment is arranged such that condensed water runs down the walls of the compartment to return to the reservoir.

3. A steam steriliser according to Claim 1 or 2, in which the condenser comprises a condensing element of high conductance material having a pathway for ambient air defined on its upper surface, and a fan for drawing ambient air across the surface.

4. A steam steriliser according to Claim 3, in which the fan may be operated at different speeds, one for use during sterilisation and a second higher speed for cooling the compartment and its contents after sterilisation.

5. A steam steriliser according to any one of the preceding Claims, which also comprises a timer for controlling the time of sterilisation.

6. A steam steriliser according to any one of the preceding Claims, in which the sterilising compartment includes a pressure release system.

7. A steam steriliser according to any one of the preceding Claims, in which the steriliser includes an easily accessible and removable heating element.

8. A steam steriliser according to any one of the preceding claims, in which the door is a fold down side door to allow ready removal of the sterilised items.

9. A steam steriliser comprising a sterilising compartment including an openable door, the door being coupled to a door opened sensor, with steam generation means coupled to electronic control means including a timer, capable of operating in an automatic mode such that when the contents of the steriliser are no longer sterile, due to the period elapsed since sterilisation or the door having been opened, the electronic control means automatically initiates a further sterilisation cycle.

10. A steam steriliser according to Claim 9, which also includes a thermometer to measure the temperature of sterisilisation.

11. A steam steriliser according to Claim 9 or 10, in which the electronic control means also includes a user interface which allows the user to time when sterilisation is to occur to delay the start of the cycle.