GB2276535A

GB2276535A - Ultrasonic cleaning of footwear

Info

Publication number: GB2276535A
Application number: GB9306732A
Authority: GB
Inventors: Victor York Gethin
Original assignee: YORK FABRICATIONS Ltd
Current assignee: YORK FABRICATIONS Ltd
Priority date: 1993-03-31
Filing date: 1993-03-31
Publication date: 1994-10-05
Anticipated expiration: 2013-03-31
Also published as: GB9306732D0; GB2276535B

Abstract

Apparatus for ultrasonic cleaning of footwear e.g. boots, while on the feet of the wearer comprises a container 6 for a cleaning liquid, a foot support 8, and at least one ultrasonic transducer 10 which may be adapted to cause cavitation within the cleaning liquid. The cleaning container of the footwear cleaning device may be integrally formed with, or attached to, a hand basin 4 so as to form a combined footwear and hand cleaning unit in which the footwear cleaning device and hand basin are arranged so that the user can wash his or her hands whilst standing in the cleaning container. The apparatus may be used in a food factory. <IMAGE>

Description

"Footwear Cleansing Devices" The invention relates to footwear cleaning devices and particularly, although not exclusively, to devices for cleaning waterproof footwear of the type commonly used in the food industry.

In the food industry cleanliness of the utmost importance. In particular, it is important that the floors of food factories are kept very clean so as to avoid possible contamination of foods in the factory.

A serious problem in food factories is that of foreign material being carried into the food factory on the footwear of employees. For example, when footwear is worn outside of the food factory, or in an unclean area of the food factory, dirt may become trapped between the treads of the soles of the footwear, and may thereby be carried into clean areas of the food factory.

There are also other applications in which clean footwear is of importance. For example, clean footwear is often important for chemical and medical applications.

The invention seeks to provide a convenient and effective footwear cleaning device.

According to the invention there is provided a footwear cleaning device comprising a cleaning container for containing a cleaning liquid, a foot supporting member located within the cleaning container and adapted to support a foot wearing footwear to be cleaned, and an ultrasonic transducer for irradiating the cleaning liquid with ultrasound so as to increase the cleaning action of the cleaning liquid.

It will be appreciated that such a device is particularly suitable for use in the food industry in view of the fact that, because the floors of food factories are often wet, it is common for people working in food factories to wear waterproof footwear. For example, rubber boots are very common. This type of footwear can of course be immersed in the cleaning liquid without suffering any adverse effects.

Preferably, the ultrasonic transducer is adapted to cause cavitation within the cleaning fluid.

Such a transducer has been found to be particularly effective at cleaning footwear due to the high stresses which are produced at solid/liquid interfaces.

Conveniently, the foot supporting member is adapted to support the whole weight of the user, so that a user can stand in the cleaning container while his or her footwear is being cleaned.

The cleaning device may further comprise a heating device for raising the temperature of the cleaning fluid.

This allows the cleaning liquid to be maintained at a temperature at which it is particularly effective at cleaning footwear.

A suitable frequency for the ultrasonic transducer to operate is in the region of 25 KHz, and is preferably between 15 KHz and 35 KHz.

Conveniently, the foot supporting member is located above the ultrasonic transducer so as to prevent footwear from coming into contact with the ultrasonic transducer.

Preferably, the cleaning container is arranged so as to extend, at least partially, below the level of an adjacent floor.

The ultrasonic transducer may comprise a plurality of separate ultrasonic transducers.

It will be appreciated that different numbers of such transducers may be used depending on the size of the cleaning container.

The cleaning container of the footwear cleaning device may be integrally formed with, or attached to, a hand basin, so as to form a combined footwear and hand cleaning unit in which the footwear cleaning device and hand basin are arranged so that the user can wash his or her hands while standing in the cleaning container.

The invention also provides a method of cleaning footwear using a footwear cleaning device as described above, the method including placing a foot wearing footwear to be cleaned, into the cleaning container and irradiating the cleaning liquid within the cleaning container with ultrasound.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a sectional view through a combined footwear and hand cleaning unit according to the invention; and Figure 2 is a sectional view along the line A-A of Figure 1.

The combined footwear and hand cleaning unit 1 comprises a footwear cleaning device 2 and a hand basin 4.

The footwear cleaning device 2 comprises a cleaning container 6, a foot supporting grid 8, three ultrasonic transducers 10, and an electric immersion heating element 12.

The cleaning container 6 contains a cleaning fluid 14, the upper level of the cleaning fluid 14 being indicated by the dotted line 16. The cleaning fluid 14 contains a detergent which has been found to be effective at cleaning rubber footwear at a temperature of between 300C and 500c. The heating element 12 raises the cleaning fluid 14 to the correct temperature.

The three ultrasonic transducers 10 irradiate the cleaning fluid 14 with ultrasound, which increases the cleaning efficacy of the cleaning fluid 14. Each of the ultrasonic transducers 10 is shaped as an elongate rectangular bar, as best shown in Figure 2.

The base 18 of the cleaning container 6 is formed with an elongate trough 20 which extends perpendicular to the direction of the longitudinal axes of the ultrasonic transducers 10. The heating element 12 is located within the trough 20 below the ultrasonic transducers 10. Each ultrasonic transducer 10 is connected to the base 18 by bolts 22.

The supporting grid 8 is formed with apertures (not shown) which allow the cleaning fluid 14, and also ultrasound radiation, to pass through the supporting grid 8. The supporting grid 8 is a flat structure which is arranged at substantially the same level as, and is substantially coplanar with, the adjacent surface of the floor 24. This conveniently allows a user to step over a side wall 26 of the cleaning container 6 and onto the supporting grid 8. The supporting grid 8 is located just above the ultrasonic transducers 10, and is supported by the walls of the cleaning container 6 so that, when a user stands on the supporting grid 8, no pressure is applied to the ultrasonic transducers 10. The supporting grid 8 may of course be integral with the cleaning container 6.

The ultrasonic transducers 10 produce circulation currents within the cleaning fluid 14 which enhance cleaning of footwear immersed in the cleaning fluid 14. The ultrasonic transducers 10 operate at a frequency of around 25 KHz, and the amplitude of the ultrasonic radiation produced by the ultrasonic transducers 10 is sufficient to cause cavitation within the cleaning fluid 14.

Cavitation is a complicated process which involves the creation of bubbles within the cleaning fluid 14 as a result of ultrasound pressure. The bubbles may, for example, be formed of air, or of vapour of the cleaning fluid 14. Such cavitation causes high stresses to be created at the interface of the cleaning fluid 14 and the solid surface of the footwear. These stresses act on contaminants attached to the footwear so as to release them from the footwear and subsequently disperse them in the cleaning fluid 14 by virtue of the high level of agitation of the cleaning fluid 14. Cavitation also promotes the emulsification of oily contaminants, and increases the attractive forces between the contaminant and the cleaning fluid 14.

The three ultrasonic transducers 10 operate separately, and each is provided with its own vibration mechanism (not shown). If a larger cleaning container is required, for example so as to accommodate several users at once, a larger number of such ultrasonic transducers may be used.

The cleaning container 6 is formed from stainless steel. The hand basin 4 is also formed from stainless steel, and is connected to the cleaning container 6 by means of a stainless steel wall 28. The hand basin 4 is provided with a stainless steel rear splash wall 30.

In use, a user stands on the supporting grid 8 so that his or her footwear is immersed in the cleaning fluid 14. While the footwear is being cleaned by ultrasonic radiation produced by the ultrasonic transducers 10, the user can wash his or her hands using the hand basin 4. It will be appreciated that the cleaning unit enables a large number of people working in a food factory to conveniently clean their footwear and their hands each time they re-enter the factory.

Claims

1. A footwear cleaning device comprising a cleaning container for containing a cleaning liquid, a foot supporting member located within the cleaning container and adapted to support a foot wearing footwear to be cleaned, and an ultrasonic transducer for irradiating the cleaning liquid with ultrasound so as to increase the cleaning action of the cleaning liquid.

2. A footwear cleaning device as claimed in claim 1, wherein the ultrasonic transducer is adapted to cause cavitation within the cleaning fluid.

3. A footwear cleaning device as claimed in claim 1 or claim 2, wherein the foot supporting member is adapted to support the whole weight of the user so that a user can stand in the cleaning container while his or her footwear is being cleaned.

4. A footwear cleaning device as claimed in any one of the preceding claims, further comprising a heating device for raising the temperature of the cleaning fluid.

5. A footwear cleaning device as claimed in any one of the preceding claims wherein the ultrasonic transducer is arranged to operate between 15KHz and 35KHz.

6. A footwear cleaning device as claimed in any one of the preceding claims, wherein the footwear supporting member is located above the ultrasonic transducer.

7. A footwear cleaning device as claimed in any one of the preceding claims, wherein the cleaning container is arranged so as to extend, at least partially, below the level of an adjacent floor.

8. A footwear cleaning device as claimed in any one of the preceding claims, comprising a plurality of separate ultrasonic transducers.

9. A footwear cleaning device as claimed in any one of the preceding claims, wherein the cleaning container is integrally formed with, or attached to, a hand basin, so as to form a combined footwear and hand cleaning unit in which the footwear cleaning device and hand basin are arranged so that the user can wash his or her hands whilst standing in the cleaning container.

10. A footwear cleaning device substantially as hereinbefore described with reference to the accompanying drawings.

11. A method of cleaning footwear using a footwear cleaning device as claimed in any one of the preceding claims, the method including placing the footwear to be cleaned into the cleaning container and irradiating the clean liquid within the cleaning container with ultrasound.