DE102023101996A1 - Device for preventing retrograde contamination - Google Patents

Abstract

The invention relates to a device comprising a filter unit, wherein the filter unit has a chamber which is lined with a fleece, wherein the fleece is coated with a bactericidal material and/or particles which are coated with a bactericidal material are located within the chamber lined with the fleece. The invention is further directed to the use of the device for reducing or preventing retrograde contamination in water systems or to a method for preventing or reducing retrograde contamination in water systems.

Description

The invention relates to a device comprising a filter unit, wherein the filter unit has a chamber which is lined with a fleece, wherein the fleece is coated with a bactericidal material and/or particles which are coated with a bactericidal material are located within the chamber lined with the fleece. The invention is further directed to the use of the device for reducing or preventing retrograde contamination in water systems or to a method for preventing or reducing retrograde contamination in water systems.

Retrograde contamination of water-carrying parts and systems, especially when not in use, is a well-known problem. Bacteria can adhere to the outlet or aerator of a faucet or water dispenser and multiply through the surrounding air or through touching and wiping. Over time, the bacteria can migrate into the interior of the pipe and contaminate the pipe and the water system. Compliance with the drinking water regulations is then usually no longer ensured. Retrograde contamination in water systems is a well-known phenomenon and problem that has so far been inadequately solved by various methods, such as UV light, ozone or heating the outlet or the water to kill bacteria, but all of these have some disadvantages.

Thermal germ barriers are known in the state of the art today, for example from Ionox (now BRITA), which are used in EP 0 983 961 A1 “Device for germ-free dispensing of beverages”, in which the spout of a water dispenser is heated continuously or cyclically in order to kill adhering bacteria and prevent them from growing in.

Also known in the art is ozonation, whereby ozone is generated in the water-carrying devices by means of an ozone generator and fed into the drinking water in order to kill existing bacteria up to the outlet.

It is also known that UV light is generated in water-carrying devices using a UV or UV LED lamp and is introduced into the drinking water to kill any bacteria present. UV lamps are often used in the outlet area to prevent retrograde contamination in particular.

In the EN 10 2006 06 23 52 A1 The bacteria are also killed by thermal heating of the water in the water-carrying device.

Due to years of work in the field of water dispensers, during which bacterial contamination due to retrograde contamination of the water system has repeatedly emerged and some of them have had to be shut down or disinfected, the following disadvantages arise for the known systems.

When using a thermal germ barrier, the water is dried out by heating the outlet and leads to calcification of the outlet. The heated outlet must be protected from contact. The water in the outlet is heated to a high degree. The disadvantage of water dispensers with chilled water is the heating up, especially since this also requires electricity.

With regard to ozonation, it must be noted that ozone must be completely broken down before it is suitable for drinking, otherwise it can be harmful to health and change the taste. An ozone source is also complex and also requires a power supply.

UV light is harmful when it is visible or comes into contact with skin and must therefore be completely encapsulated. The generation of UV light also requires electricity. The line must be completely illuminated to achieve full effect. UV generates heat, which must also be dissipated.

When it comes to thermal heating of water, it can also be said that energy is required for heating. Heating is counterproductive for devices for chilled drinking water and requires good temperature-tolerant materials. The heated water must be cooled again or discarded before drinking water can be drawn.

The object of the present invention was therefore to eliminate the disadvantages of the prior art and to provide a device which can effectively prevent the retrograde contamination of water-carrying systems.

The object was achieved by a device comprising a filter unit 1, wherein the filter unit has a chamber which is lined with a fleece, wherein the fleece is coated with a bactericidal material and/or particles which are coated with a bactericidal material are located within the chamber lined with the fleece.

The filter unit 1 is arranged within an outlet system of a water supply device. A normal water tap 2 or a water dispenser 3 is to be regarded as a water supply device within the meaning of the invention. However, the system according to the invention can also be used in a standard household water filter.

The filter unit 1 is designed as a perlator chamber 4 or as a cartridge chamber 6 and is arranged on the outlet side of the water supply device.

According to one embodiment of the invention, the aerator chamber 4 or the cartridge chamber 6 is provided with a fleece, wherein the fleece is coated with a bactericidal material.

A fleece in the sense of the invention is understood to be a three-dimensional network of natural or synthetic fibers, in particular polymer fibers. As an alternative to a fleece, a fiber fabric can also be used according to the invention.

The material for the fleece or fiber fabric is preferably cotton, flax, wool, cellulose, glass fiber, basalt, viscose and polyester (PET, PBT, PP, PA, PE, aramid).

As a material for the coating, a polyamine is preferred. Examples of polyamines are the following: polyamines such as any polyalkylamines, e.g. polyvinylamine, polyalkylamine, polyethyleneimine and polylysine etc. Among these, polyalkylamines are preferred, even more preferably polyvinylamine and polyallylamine, with polyvinylamine being particularly preferred. Preferably, the particles used are coated substantially on their outer surface. Substantially here means more than 90% of the coating is on the outer surface, preferably more than 95%, more preferably more than 99%.

The preferred molecular weight of the polyamine used according to the invention is preferably in the range from 5,000 to 50,000 g/mol, which applies in particular, but not only, to the specified polyvinylamine.

The polyamine or the particles coated therewith, the fleece or the fabric, preferably have a concentration of the amino groups determined by titration of at least 300 pmol/mL, more preferably at least 600 pmol/mL, and even more preferably at least 1000 pmol/mL. The concentration of the amino groups determined by titration is understood to mean the concentration which is obtained by breakthrough measurement with 4-toluenesulphonic acid according to the analytical methods specified in the examples section of this application.

The polyamine-coated particles used preferably have a dry bulk density in the range of 0.25 g/mL to 0.8 g/mL, even more preferably 0.3 g/mL to 0.7 g/mL. In other words, the particles are extremely light overall, which is ensured by the high porosity obtained. Despite the high porosity and the low weight of the particles, they have a relatively high mechanical strength or rigidity.

The mean pore size of the biocidal porous particles determined by inverse size exclusion chromatography is preferably in the range of 1 nm to 100 nm, more preferably 2 nm to 80 nm.

The biocidal, porous particles are preferably in a substantially spherical shape. Their average particle size is preferably in the range of 5 pm to 1000 pm, more preferably in the range of 20 to 300 pm.

According to a further embodiment, the nonwoven fabric can be coated or uncoated. A polyamine is preferred as the material for the coating. Examples of polyamines are the following: polyamines, such as any polyalkylamines, e.g. polyvinylamine, polyalkylamine, polyethyleneimine and polylysine etc. Among these, polyalkylamines are preferred, even more preferably polyvinylamine and polyallylamine, with polyvinylamine being particularly preferred.

The preferred molecular weight of the polyamine used is preferably in the range of 5,000 to 50,000 g/mol, which applies in particular to the specified polyvinylamine.

According to a further embodiment of the device according to the invention, the aerator chamber 4 or cartridge chamber 6 designed with the fleece can contain particles, wherein the particles are substantially coated on the outer surface with a polyamine.

Preferably, the polyamine is cross-linked within the coating. The polyamine is usually cross-linked with itself and does not form covalent bonds to the surface of the carrier material or porous material. However, a covalent bond to the carrier material or porous material can also occur. Preferably, however, the polyamine is not covalently bound to the particles of the material.

It is also preferred that in the case of the coated fleece or fabric, the polyamine is cross-linked and preferably not covalently bound to the fleece or fabric. The cross-linking of the polyamine ensures sufficient stability so that the polyamine cannot be washed out from the surface of the fleece or fabric or from the pores of the particles. In addition, the cross-linking ensures the possibility of a certain swelling, which makes the functional groups of the polyamine more easily accessible for reaction with the bacteria in the medium and thus increases the effectiveness.

In the embodiment in which the fleece or fabric in the aerator chamber or cartridge chamber has additional bactericide-coated particles, it is also preferred that the fleece or fabric has a smaller pore size or mesh size than the particles or porous particles. This can prevent particles or porous particles from getting into the eluate, i.e. the supposedly purified drinking water. It is preferred that the particles or porous particles in the aerator chamber or cartridge chamber have a particle size of 100 - 1000 pm in diameter.

A further object of the present invention is accordingly the use of the device described above for reducing or preventing retrograde contamination in water systems.

A still further object of the present invention is accordingly a method for preventing or reducing retrograde contamination in water systems, wherein contaminated water is passed through a device as described above.

The basis of the invention is an antibacterial filter material that is WO2020/187746 A1 “Particles with biocidal coating” or WO2019/025488 A1 "Removal of bacteria from drinking water via filtration" is described in detail. In particular, a carrier material coated with polyvinylamine is to be used. For this purpose, a commercially available aerator 1 is used, which is used for regulating the water jet on water systems, such as faucets 2 or water dispensers 3. The upper chamber 4 is lined with fine-pored fleece and the coated particles are filled in. The fleece serves to retain the particles and has a smaller pore size or mesh size than the particles, which are usually between 100 pm and 1000 pm in diameter.

The coated particles should be well packed in the chamber so that no empty spaces or channels can form. The chamber is closed and the aerator is inserted as usual.

A specially manufactured cartridge 5 can also be used, through which water can flow axially from top to bottom and also has a chamber 6 equipped with a finer fleece in which the coated particles are located. The cartridge can therefore accommodate more particles in order to ensure functionality in larger application systems.

In normal operation, i.e. when water is drawn, drinking water flows through the water system and through the aerator or the cartridge with the coated particles into a drinking glass, for example. The particles allow the water to pass through almost unhindered. The system should behave as usual and dispense the water. Only when not in use, i.e. when there is water in the system, should the coated particles in the outlet develop their biocidal effect.

Bacteria that are carried through the air or by touching the outlet with fingers or a cloth and find their way through the aerator into the water pipe and the water system are now killed by contact with the coated particles or the coated fleece/fabric. The polyamine on the particles has the property of making bacteria inactive. Bacteria are thus prevented from getting into the interior of the water system and causing retrograde contamination. In the case of the aerator, a small layer of particles on the outlet of less than 1 g is usually sufficient for this.

According to the association's rules, water dispensers should be cleaned and disinfected every six months (6 months), which also means the service life of the aerator or the cartridge with coated particles. During this period, retrograde contamination should be prevented.

Regular rinsing of the particles during normal operation flushes out inactive bacteria adhering to the coated particles, which increases the lifespan of the antibacterial effect.

The particles must be well packed in the aerator or cartridge so that bacteria definitely come into contact with the surface of the particles on their way into the water. Well packed means a packing density of about 66% +/- 10%, since the particles are approximately spherical.

The device according to the invention prevents retrograde contamination of water systems. The coated particles can be integrated into commercially available aerators or filled into a simple cartridge that can be inserted into the outlet of a water system. The particles form a "barrier layer" that allows the water to flow through almost unhindered during normal operation and develops its antibacterial effect when the system is not running to prevent retrograde contamination. The invention does not require an additional energy source or to be otherwise encapsulated or protected. It can be retrofitted into most existing systems. The water system does not require any other additional technical devices. The invention is food-safe and very cost-effective.

List of reference symbols:

1

Filter unit

2

water tap

3

Water dispenser

4

Perlator chamber

5

Filter cartridge

6

Cartridge chamber

Character description:

• 1 : Schematic overview with faucet or water dispenser and aerator chamber or cartridge chamber
• 2 : Perlator 1 with coated particles in a water system during use.
• 3 : Cartridge 5 with coated particles in a water system during use.
• 4 : Perlator 1 with coated particles in a water system at standstill.
• 5 : Cartridge 5 with coated particles in a water system at standstill.

The invention will now be explained in more detail using embodiments with reference to the figures, although these are not to be understood as limiting the scope of the invention.

Example 1:

Perlator 1 with coated particles in a water system during use.

Here, in a water system, water from a water pipe is passed through a perlator chamber 4, which is lined with fine-pored fleece and filled with coated particles. The air intake is located below the perlator chamber and the perlator is located below it, and it is clear that free flow of water can be ensured during normal operation without causing any impairment.

Example 2:

Cartridge 6 with coated particles in a water system during use.

As in example 1, water from the water system is guided through a cartridge chamber 6 within a water pipe, which is lined with fine-pored fleece and filled with coated particles. Here, too, free flow of water can be guaranteed during normal operation.

Example 3:

Perlator 1 with coated particles in a water system at standstill.

In this example, standing water was assumed in a water pipe, which rests on an aerator chamber 4, which is lined with fine-pored fleece and filled with coated particles. A retrograde migration of the bacteria would normally be induced via the aerator and the air intake, and this migration leads to inactivity through contact with the particles.

Example 4:

Cartridge 5 with coated particles in a water system at standstill.

As in the example above, it is assumed that there is standing water in a water pipe; here there is a cartridge chamber 6 lined with fine-pored fleece and filled with coated particles. It is evident that retrograde migration of bacteria from the outlet side cannot take place, as they are inactivated when they come into contact with the particles.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• EP 0983961 A1 [0003]
• DE 102006062352 A1 [0006]
• WO 2020187746 A1 [0033]
• WO 2019025488 A1 [0033]

Claims (12)

Device comprising a filter unit (1), wherein the filter unit (1) has a chamber which is lined with a fleece or fabric, characterized in that the fleece or fabric is coated with a bactericidal material and/or within the chamber lined with the fleece or fabric there are particles which are coated with a bactericidal material. Device according to Claim 1 , wherein the filter unit is arranged within an outlet system of a water supply facility. Device according to Claim 2 , wherein the water supply device is a water tap (2) or a water dispenser (3). Device according to one of the Claims 2 or 3 , wherein the filter unit is designed as aerator chamber (4) or as a cartridge chamber (6) and is arranged on the outlet side of the water supply device. Device according to one of the Claims 1 until 4 , wherein the fleece or fabric is coated with a polyamine. Device according to one of the Claims 1 until 4 , wherein the particles are substantially coated on the outer surface with a polyamine. Device according to Claim 6 or, wherein the polyamine is cross-linked. Device according to one of the Claims 5 until 7 , wherein the polyamine is not covalently bound to the fleece, fabric or particles. Device according to one of the Claims 1 until 8th , wherein the fleece or fabric has a smaller pore size or mesh size than the particles. Device according to one of the Claims 1 until 9 , wherein the particles in the aerator chamber (4) have a particle size of 100 mm to 1000 mm in diameter. Use of a device according to one of the Claims 1 until 10 to reduce or prevent retrograde contamination in water systems. Method for preventing or reducing retrograde contamination in water systems, wherein contaminated water is filtered through a device according to one of the Claims 1 until 10 to be led.