GB2335262A

GB2335262A - Steam humidification system for a refrigerated display cabinet

Info

Publication number: GB2335262A
Application number: GB9805043A
Authority: GB
Inventors: Robert Alexander Arthur
Original assignee: Marks and Spencer PLC
Current assignee: Marks and Spencer PLC
Priority date: 1998-03-09
Filing date: 1998-03-09
Publication date: 1999-09-15
Also published as: GB9805043D0

Abstract

A refrigerator display cabinet is equipped with a steam humidification system comprising means for generating a constant supply of steam and means for its distribution to said cabinet to provide the necessary humidification. The distribution system (10) consists of a tank (11) in which water (12) is heated by a heating element (13), and manifold (14) having a plurality of evenly-spaced nozzles (17) for distributing water vapour throughout the refrigerated display cabinet. The manifold is inclined downwardly to return condensate back into the tank (11).

Description

2335262 1 Steam Humidification System This invention relates to the use of

steam for the humidification of refrigeration units.

The very action of refrigeration dehydrates unwrapped food products, especially those with a high water content, such as fresh meat and fish. This leads to discoloration and weight loss, reducing the sales potential of the product.

By 'refrigeration' is meant storage at temperature below room temperature by use of heat pumps or the like. This definition can be taken to include storage in a standard Z> refrigerator or a freezer. More particularly, the definition relates to storage in open refrigerated display cabinets.

To overcome the dehydration mentioned above, humidification systems are used within the refrigeration unit to maintain a high humidity within the refrigerated area, thus reducing product deterioration. Various designs of humidification systems are known; generally these make use of water droplets which fall onto the product to maintain its condition.

However, the quality of water supplied to the humidification systems cannot be guaranteed. Tests have shown water samples to contain traces of Legionella, Listeria and other harmful bacteria and parasites.

To attempt to combat this poor water quality, purification systems have been used. Typically these use methods such as reverse osmosis and UV radiation to improve the quality of the water. However, such systems are costly, unreliable and require extensive cleaning and maintenance. There is, therefore, a requirement for a safer and more costeffective solution.

2 Therefore, it is a feature of the present invention to allow the use of steam as the source of water vapour (ie a 'fog' of very fine water droplets) to maintain the levels of humidity within a refrigeration unit. It is generally known that parasites such as bacteria are killed by exposure to steam. In addition, the means to generate steam are straightforward. Therefore, the use of steam to provide humidification would be both safer and more cost-effective than humidification methods previously known.

According to the invention, there is provided a refrigeration unit equipped with a humidification system. said system comprising means for producing a constantly available supply of steam and means for the distribution of steam to said unit to provide the necessary humidification.

In use, low pressure steam is generated by, for example, a boiler; the steam is then introduced into the refrigerated part of the unit. As soon as the steam comes into contact with the cold air, it is condensed into water vapour which then diffuses (or is entrained) throughout the refrigerated unit. Under these conditions, the relative humidity is typically over 80%, preferably over 90% and more preferably over 95%.

As water vapour is lost from the unit, a constant supply of steam is necessary. This is particularly the case where the unit is an open display cabinet and water vapour is constantly being removed by the air conditioning.

In a preferred embodiment of the invention, steam is distributed to the system by means of one or more manifolds and released into the unit via nozzles.

In a particularly preferred embodiment of the invention, the manifolds are aligned at such an angle so that any water condensing therein may easily return to the boiler or other steam generation means.

3 The invention will now be described by way of example with reference to the accompanying drawing. However, the invention shall not be taken as limited to that in the drawing.

Figure 1 is a schematic representation of a steam generation and distribution system 10 consisting of a tank 11 in which water 12 is heated by a heating element 13. The tank 11 is connected to a manifold 14 by means of a pipe 15. At the end of each outlet 16 of the manifold 14 is located a nozzle 17. The nozzles 17 are spaced evenly to ensure an even distribution of water vapour throughout the refrigeration unit. Water vapour emerges from the nozzles 17 into the rear of the refrigerated area. The manifold 14 is inclined downwards towards the pipe 15. The entire system is insulated by lagging 18.

0 Steam is generated by heating water 12 in the tank 11 and flows through the manifold 14, out of the nozzles 17 into the rear of the refrigerated part of the unit. Any water which condenses in the manifold 14 flows back via the pipe 13 into the tank 11.

4

Claims

CLAIMS:

1. A refrigeration unit equipped with a humidification system, said system comprising means for producing a constantly available supply of steam and means for the distribution of steam to said unit to provide the necessary humidification.

2. A refrigeration unit equipped with a steam humidification system according to claim 1, wherein the means for distribution of steam includes one or more manifolds.

3. A refrigeration unit equipped with a steam humidification system according to claim 2, wherein the manifolds are positioned at such an angle so that water condensing therein may easily return to the steam generation means. A refrigeration unit equipped with a steam humidification system according to any of the previous claims, wherein all or part of the system is insulated.

5. A refrigeration unit equipped with a steam humidification system according to any of the previous claims, wherein said refrigeration unit takes the form of a refrigerated display cabinet.

6. Use of a refrigeration unit equipped with a steam humidification system according to any of the previous claims for the preservation of foodstuffs while retaining their natural moisture content.