GB1593489A - Dehumidifying devices in buildings - Google Patents

Description

(54) DEHUMIDIFYING DEVICES IN BUILDINGS (71) I, GEORGE ALFRED FORBES, a British subject, of 75 Ellerby Street, London, S.W.6., England, do hereby declare the invention, for which I pray that 2 patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a dehumidifying device for building structures.

A high humidity atmosphere often exists at least in certain spaces within building structures, for example kitchens and bathrooms of houses. This high humidity can lead to deposition of water on the internal surfaces of windows, wails, etc., due to the existence of temperature differentials. The problem can be overcome to some extent by providing additional thermal insulation on the internal surfaces where condensation is likely to occur, e.g. double glazing, or by ventilation. Both solutions are expensive, in the latter case due to increased heat losses.

In addition, wall constructions are often porous, so that condensation occurs in the interstices within the walls, causing problems of staining and/of mould growth. Heat losses are increased as a result of reduction in the thermal efficiency of the walls due to the condensation of water within them.

These interstitial condensation problems are basically caused by the existence of temperature and vapour pressure differentials between the internal and external atmospheres.

Water vapour is drawn on to and into the wall construction from the internal atmosphere and migrates towards the lower external temperature. Condensation occurs at the dewpoint temperature, which often occurs at a depth within the wall.

An object of the invention is to provide a dehumidifying device to assist in overcoming the above-described condensation problems.

According to the invention, there is provided in a building a dehumidifying device comprising an open-ended vent tube extending through a building wall, or at least one wall leaf of a cavity wall construction, from the interior to the exterior thereof with the internal end of the tube not being lower than the external end thereof, and a mass of heatinsulating material with which said vent tube is loosely packed, said heat-insulating material being selected and packed so that the loosely packed mass thereof has minimum resistance to passage of water vapour.

The loosely packed mass of heat-insulating material should advantageously be substantially non-hygrcscopic so that its tendency to hold water is minimal. To this end, it is preferable that the material is packed sufficiently loosely so as to minimize effects of capillary attraction tending to retain water on the packed mass of material.

The heat-insulating mass preferably consists of loosely packed fibrous material such as mineral or glass wool.

Since the dewpoint may sometimes occur within the vent, the tube preferably slopes slightly downwardly to the exterior so that condensed water can drain to the outside.

In the case of a cavity wall construction, the vent tube may extend right through the double leaved wall from the interior of the building to the outside. Alternatively, two separate shorter tubes may be employed, one extending from the building interior through the internal wall leaf to project into the wall cavity and the other extending from within the cavity through the external wall leaf to the outside, the former tube preferably being positioned just above the latter tube. The alternative latter arrangement permits water vapour in the cavity to be drawn to the outside through the tube extending through the external wall leaf. This can also be achieved with the longer vent which extends through both wall leaves, by providing one or more perforations in the top of the tube at a point within the wall cavity.

Two practical embodiments in accordance with the invention are illustrated in Figures 1 and the the accompanying drawings.

In Figure 1, a single vent tube 10 extends from the inside (I) of the building to the outside (0), through a cavity wall construction having an internal wall leaf 11 and an ex eternal wall leaf 12 separated by a cavity 13.

The tube slopes slightly downwardly from the inside to the outside and is loosely packed with fibrous heat insulating material 14 such as mineral or glass wool. The upper half of the vent tube 10 is perforated, as indicated at 15 to provide for entry of water and water vapour from the cavity 13. The perforations 15 may be restricted to the portion of the vent tube actually disposed in the cavity 13, if desired. Grilles for the end faces of the tube are shown at 16. The vent tube provides an outlet point through the wall construction for the water vapour present in a high humidity internal atmosphere and enables water vapour within the wall cavity to "breath out" with minimal resistance to the external atmosphere.

In the alternative arrangement of Figure 2, the tube 10 is replaced by two shorter vent tubes 20 and 21, preferably perforated in their upper portions to assist entry of moisture from the cavity 13. Other references in Figure 2 correspond to those of Figure 1, and the complete device functions in similar manner.

WHAT I CLAIM IS:- 1. In a building, a dehumidifying device comprising an open-ended vent tube extending through a building wall, or at least one wall leaf of a cavity wall construction, from the interior to the exterior thereof with the internal end of the tube not being lower than the external end thereof, and a mass of heatinsulating material with which said vent tube is loosely packed, said heat-insulating material being selected and packed so that the loosely packed mass thereof has minimum resistance to passage of water vapour.

2. A device as claimed in Claim 1, wherein the loosely packed mass of heat-insulating material is substantially non-hygroscopic.

3. A device as claimed in Claim 1 or Claim 2, wherein the heat-insulating mass consists of loosely packed fibrous material.

4. A device as claimed in Claim 3, wherein the fibrous material is mineral or glass wool.

5. A device as claimed in any preceding Claim, wherein a section of the tube wall is perforated to allow the passage therethrough of water vapour.

6. A device as claimed in any preceding Claim, wherein the tube slopes slightly downwardly to the exterior, so that condensed water can drain to the outside.

7. A device as claimed in any preceding Claim in which the wall is a cavity wall construction, wherein the vent tube extends right through both wall leaves and the cavity therebetween from the interior of the building to the outside.

8. A device as claimed in Claim 7, wherein the vent tube has one or more perforations in the upper half of the tube at least at a point within the wall cavity.

9. A device as claimed in any of Claims 1 to 5 in which the wall is a cavity wall construction, wherein two separate vent tubes are provided, one extending from the building interior through the internal wall leaf to project into the wall cavity and the other extending from within the cavity through the external wall leaf to the outside.

10. A device as claimed in Claim 9, wherein said one vent tube is positioned just above said other vent tube.

11. In a building, a dehumidifying device substantially as hereinbefore described with reference to, and as illustrated in, Figure 1 or Figure 2 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. eternal wall leaf 12 separated by a cavity 13. The tube slopes slightly downwardly from the inside to the outside and is loosely packed with fibrous heat insulating material 14 such as mineral or glass wool. The upper half of the vent tube 10 is perforated, as indicated at 15 to provide for entry of water and water vapour from the cavity 13. The perforations 15 may be restricted to the portion of the vent tube actually disposed in the cavity 13, if desired. Grilles for the end faces of the tube are shown at 16. The vent tube provides an outlet point through the wall construction for the water vapour present in a high humidity internal atmosphere and enables water vapour within the wall cavity to "breath out" with minimal resistance to the external atmosphere. In the alternative arrangement of Figure 2, the tube 10 is replaced by two shorter vent tubes 20 and 21, preferably perforated in their upper portions to assist entry of moisture from the cavity 13. Other references in Figure 2 correspond to those of Figure 1, and the complete device functions in similar manner. WHAT I CLAIM IS:-

1. In a building, a dehumidifying device comprising an open-ended vent tube extending through a building wall, or at least one wall leaf of a cavity wall construction, from the interior to the exterior thereof with the internal end of the tube not being lower than the external end thereof, and a mass of heatinsulating material with which said vent tube is loosely packed, said heat-insulating material being selected and packed so that the loosely packed mass thereof has minimum resistance to passage of water vapour.

2. A device as claimed in Claim 1, wherein the loosely packed mass of heat-insulating material is substantially non-hygroscopic.

3. A device as claimed in Claim 1 or Claim 2, wherein the heat-insulating mass consists of loosely packed fibrous material.

4. A device as claimed in Claim 3, wherein the fibrous material is mineral or glass wool.

5. A device as claimed in any preceding Claim, wherein a section of the tube wall is perforated to allow the passage therethrough of water vapour.

6. A device as claimed in any preceding Claim, wherein the tube slopes slightly downwardly to the exterior, so that condensed water can drain to the outside.

7. A device as claimed in any preceding Claim in which the wall is a cavity wall construction, wherein the vent tube extends right through both wall leaves and the cavity therebetween from the interior of the building to the outside.

8. A device as claimed in Claim 7, wherein the vent tube has one or more perforations in the upper half of the tube at least at a point within the wall cavity.

9. A device as claimed in any of Claims 1 to 5 in which the wall is a cavity wall construction, wherein two separate vent tubes are provided, one extending from the building interior through the internal wall leaf to project into the wall cavity and the other extending from within the cavity through the external wall leaf to the outside.

10. A device as claimed in Claim 9, wherein said one vent tube is positioned just above said other vent tube.

11. In a building, a dehumidifying device substantially as hereinbefore described with reference to, and as illustrated in, Figure 1 or Figure 2 of the accompanying drawings.