WO2000042267A1

WO2000042267A1 - Air-distribution device in a ventilation system

Info

Publication number: WO2000042267A1
Application number: PCT/SE1999/002462
Authority: WO
Inventors: Mathias Ohlsson; Bengt Steneby
Original assignee: Nivell System Ab
Priority date: 1999-01-13
Filing date: 1999-12-22
Publication date: 2000-07-20
Also published as: SE9900058L; AU2136800A; SE513398C2; SE9900058D0

Abstract

An air-distribution device in a ventilation system for a subfloor (2) supporting a floor construction on a plurality of joists (6), supported by level-adjusting spacer screws (8) to create a free space (5) between the subfloor (2) and the floor construction, the ventilation system having air-inlet devices (13) that are in open communication with an opening (14) in the floor construction to said space. In accordance with the invention, the device has an elongate plate-shaped body (16), mounted to the joist (6a) nearest said openings for the air-inlet devices, which plate body has a waist part (17), a foot part (18) and a top part (19), the two last-mentioned parts being flexibly connected to the waist part. Further, the device has spacers (26) at the foot part to create an air gap (27) between the same and the subfloor. The plate body (16) is anchored to the joist (6a) by means of the top part and to the subfloor by means of the foot part. The waist part forms an obtuse angle with the foot part.

Description

Air-distribution device in a ventilation system

The present invention relates to a device for distributing ventilation air in a ventilation system for a subfloor in a building, in which a floor construction is arranged on the subfloor and comprises a plurality of joists arranged at a pre-determined distance from each other and supported by a plurality of level-adjusting spacer screws resting on the subfloor to create a free passage between the joist and the subfloor and a free, coherent space, including said passages, between the subfloor and the floor construction, which space forms part of said ventilation system, which further comprises a plurality of air-inlet devices arranged at a pre-determined distance from each other by at least one wall and each being in open communication with an opening in the floor construction to said space.

The ventilation of subfloors, i.e. the rigid foundation supporting floor constructions, requires the ventilating air to be distributed evenly across the entire surface of the subfloor. Air-flows take place towards a created partial vacuum in the exhaust air, the supply air being taken from the room or premises above the floor construction. The air is extracted from the subfloor by way of pipes connected to an exhaust-air fan, which pipes are provided with holes according to a system to obtain uniform evacuation of the ventilation air along the entire length of the pipe. The supply air for the subfloor has hitherto been taken through air-pervious skirting-boards, which distribute the supply air to the subfloor along their entire lengths. The distribution of the ventilating air and a drop in pressure occurs above the flooring layer so that the whole space between the subfloor and the flooring layer is subject to a lowered pressure. This requires the ground sill to be air-proofed to a high standard so that no undesirable draught arises. The air-pervious skirting-board can be designed in a multitude of different ways. For instance, it can have evenly distributed cut-outs to provide room for air to pass or it can be mounted on site with spacer blocks . To negotiate turned-up carpet ends, in the latter case, a fillet is needed on the top side to cover the edge of the carpet. In rooms with a water supply, a drip-proof fillet must be tightly fitted to the wall above the air-pervious skirting-board to protect against penetration by water without impeding the passage of air. To prevent dust in the indoor air from being drawn down into and accumulating on the ventilated subfloor, where organic matter can cause mildew, amongst other things, a filter strip is commonly placed in an appropriately designed space in the air-pervious skirting-board. The filter strip will of necessity run along the entire vented length of the skirting-board.

The problems associated with an air-pervious skirting-board are that, whatever its design, it must be functionally satisfactory in technical respects along its entire physical length and during its entire service life. During fitting, there are many work details where defects can arise. The air-pervious skirting-board requires that the flooring layer terminates before it reaches the wall so as to create an air gap. The gap must not be so wide that the skirting is not supported whilst being fitted and must not be so narrow that its capacity to allow air to pass is impaired. The movements in the flooring material caused by moisture must also be considered so that the air gap is not blocked when the flooring material expands, which applies particularly to wooden floors. If a carpet is laid, it must be cut in such a way that the air gap is not blocked. Obviously, the air-pervious skirting-board itself must be correctly executed and sealed in its join with the floor or carpet so that dust or cleaning water is not drawn in under the fillet and down underneath the floor, as the pressure is lower behind the fillet on its underside than in the room.

When a filter is integrated into the air-pervious skirting-board, it must be changed regularly, approximately every 5 years, to ensure uniform ventilation of the subfloor. When changing a filter, the air-pervious skirting-board must be dismantled along its entire length. This may well result in the whole or parts of the air-pervious skirting-board having to be replaced, re-use not being possible due to damage during dismantling, and in the surface layer of the walls being damaged so that repairs become necessary. If the carpet is turned up against the air-pervious skirting-board, the carpet must also be re-laid. Operations of this character will disturb occupier use of the premises in question. For the above-mentioned reasons, there is a significant risk of the filters not being changed sufficiently often in many cases, which can lead to damage to the affected building components. It is worth nothing that, in spite of the air-pervious skirting-board being dismantled during filter changes, it has not been possible to inspect or to clean underneath the floor in respect of particles that may have fallen down during the dismantling work or due to the filter strip not being operational along its entire length. Because of the many shortcomings of previously used floor constructions and ventilation systems for the same, damage has occurred such that the floor constructions have had to be replaced, along with parts of the wall, and the subfloor reconditioned in one way or another.

The object of the present invention is to substantially reduce the problems discussed above and to provide an air-distribution device that makes it possible to achieve an efficient system of ventilation, such that the floor construction acquires a substantially extended service life and, in any event, does not need to be repaired or replaced because of shortcomings in the construction and/or the system of ventilation.

The air-distribution system in accordance with the invention is characterized in that it comprises an elongate plate-shaped body, rigidly mounted to the joist located nearest said openings for the air-inlet devices, which plate body includes a flat waist part, a foot part, a top part, which foot and top parts extend along the long sides of the waist part and are flexibly connected to the waist part by way of joints that are parallel to each other, and, further, a plurality of spacers arranged adjoining the foot part to create an air gap between the foot part and the subfloor at the anchorage of the plate body to the subfloor, which plate body is arranged to be anchored to said joist by means of its top part with the waist part sloping down towards the subfloor at an acute angle and forming an obtuse angle with the foot part and an obtuse or acute angle with the top part, the air gap being arranged to provide a pressure drop in the ventilation air passing through the same.

The basic idea of the invention is that the partial pressure is created not until the space underneath the floor and after the distribution of the supply air along an air channel arranged in said space and extending along the wall where the air is admitted.

The invention will be further described in the following with reference to the drawings.

Figure 1 shows schematically parts of a floor construction and ventilation system in a building, viewed from above . Figure 2 is a cross section along the line A-A in Figure 1.

Figure 3 is a perspective view of a plate body in an air-distribution device used in the floor construction in accordance with Figure 1.

Figure 4 is a perspective view of a part of the building and the floor construction, partly sliced through, in accordance with Figure 1 and shows an air-inlet device for the supply air and the plate body in accordance with Figure 3.

Figure 5 is a perspective view, substantially similar to the one in Figure 4, the air-inlet device being shown in an exploded view.

Figures 6, 7 and 8 are end views of floor constructions at different levels of elevation above the subfloor and illustrate the use of the air-distribution device in accordance with the invention with identical dimensional design in each case.

Figures 1-5 show schematically parts of a floor construction in a building with walls 1 and a rigid supporting foundation or subfloor 2, usually of concrete, which can range from smooth to relatively uneven and bumpy. The walls 1 are outer walls, each comprising a ground sill 3. The floor construction comprises a flooring 4, which together with the foundation 2 defines a space 5, and a plurality of joists 6 that carry the flooring 4. The joists 6 are provided with angled plates (not shown) to support insulation sheets, which are thereby spaced from the foundation 2. Each joist 6 is provided with a plurality of vertical holes 7 drilled through it and arranged at a pre-determined distance from each other. The drill holes 7 have a threading with small pitch. Level-adjusting spacer screws 8 having external threading with a pitch equal to that of the threading of the drill holes 7 are screwed into the drill holes 7. The screws 8 have hexagonal holes, accessible from the upper side for co-operation with a turning device, and narrow central through-holes for anchoring the screws 8 to the foundation 2 with nails or screws once the position of the joist 6 has been determined. With the aid of the screws 8, the joists 6 are positioned at a certain elevation above the foundation 2 so that a free passage 9 is created between the underside of the joist 6 and the foundation 2 and so that the top sides of the joists 6 are located in the same plane, the screws 8 maintaining sufficient screwing engagement with the joists 6 to fix and support the joists 6 at the level set and to support the remainder of the floor construction.

The first joist 6a is located a pre-determined distance from the outer wall 1 so that a channel 10 is created on the inside of the ground sill 3, which channel extends continuously along the ground sill 3.

Said passage 9 below the joists 6 as well as the channel 10 along the ground sill 3 form part of said space 5, which is thus free for air flows and continuous in all directions along the foundation 2.

The floor construction is ventilated by a ventilation system, comprising a suction source (not shown) , which can be a wall-mounted fan in connection with said space 5 underneath the floor construction via a pipe system, comprising a pipe 11, to extract air from the space 5, as indicated by arrows in Figure 1. The supply air to the space 5 underneath the floor construction is provided by the room 12 and thus consists of warm indoor air. The ventilation system comprises a plurality of air-inlet devices 13, arranged at pre-determined locations on the floor construction adjacent to a wall 1, whereby the supply air flows into and through the air-inlet devices 13 and further down into said channel 10 of the space 5 via an opening 14 in the floor construction. The ventilation system can favourably be dimensioned in accordance with the technique described in patent specification SE-509 097.

In accordance with the invention a special device is suggested to distribute the supply air advantageously as it flows down into the space 5, which device will be further described in the following.

The air-distribution device comprises an elongate, rectangular, plate-shaped body 16, manufactured in one piece from a suitable plastic material, for instance polypropylene. The plate-shaped body 16 comprises a waist part 17 with a pre-determined width, a foot part 18 and a top part 19. The foot and top parts 18, 19 are parallel to each other and sufficiently wide to be able to accommodate appropriate attachment elements 20, 21 for attachment of the body 16. The foot part 18 is flexibly connected to the waist part 17, via a continuous, tight joint 22, so that the requisite angle for each individual fitting can be set between them, see Figures 6, 7 and 8. The top part 19 is in like manner flexibly connected to the waist part 17, via a continuous, tight joint 23 so that the requisite angle for each individual fitting can be set between them, see Figures 6, 7 and 8. The two joints 22, 23, which are parallel to each other, thus have the shape of tight hinge joints so that the top and foot parts 19, 18 can be pivoted in the desired directions relative to the waist part 17. The joints 22, 23 can be created by two grooves 24, 25 being made on at least one side of a plate slab, each joint 22, 23 consisting of the thinner, remaining, non-perforated material, see Figure 3. To be relatively self-supporting, i.e. not collapsing due to its own weight, the plate-shaped body 16 should have a sheet thickness of at least 1.5 mm, preferably at least 2.0 mm. Having regard to the cost of materials, handling aspects and workability, the sheet thickness should not be exaggeratedly great. The plate-shaped body 16 is yielding to such an extent that it bends to negotiate uneven parts in the foundation 2 so that the foot part 18, in particular, adapts to such uneven parts whilst being mounted by means of the attachment elements 21.

The air-distribution device further comprises a plurality of spacers 26, equidistantly arranged along the foot part

18 and having a pre-determined length so that the foot part 18 is kept a pre-determined distance above the foundation 2, whilst defining a narrow air gap 27, which air gap 27 thus has a correspondingly pre-determined height. In the embodiment shown, the spacers 26 consist of loose plastic bushings, placed between the foot part 18 and the foundation 2 and fixed by means of suitable attachment elements 21, which extend through holes 28 in the foot part 18 and the plastic bushings 26 and are anchored in the foundation 2. The spacers 26 can be 2-6 mm long depending on the desired height of the air gap 27. The preferred height of the air gap is about 3 mm.

The plate-shaped body 16 is anchored to the inner, vertical side of the joist 6a located nearest the ground sill 3 by using suitable attachment elements 20, for instance staples, that are pressed through the top part

19 into the joist 6a in such a way that the waist part 17 issues from the underside of the joist 6a and extends at an angle down towards the foundation 2. Thereafter, the plate-shaped body 16 is anchored to the foundation 2 by way of sleeved screws 21 that are inserted through the pre-drilled holes 28 in the foot part 18 and through the plastic bushings 26 and screwed into the foundation 2, the foot part 18 adjusting itself to accommodate any unevenness in the foundation 2, thanks to its yielding property, so that the air gap 27 obtains a virtually uniform height along the foot part 18.

As is evident from Figures 6, 7 and 8, floor constructions at different levels of elevation above the subfloor 2 can employ an air-distribution device in accordance with the invention having identical dimensional design in each case, the level of elevation being determined by the length of the level-adjusting spacer screws 8. In so-called low-profile floors in accordance with Figure 8, the top part 19 can be folded downwards so as to obtain a more obtuse angle between the waist part 17 and the foot part 18, which is advantageous. Generally, this obtuse angle is between about 110° and about 175°.

As is evident from Figure 5, the air-inlet box 13 has a box-shaped filter-holder 29, which is attached to the wall 1 and which is provided with a lower front wall 30 of low height and a front opening 31 extending upwards therefrom. The filter-holder 29 has in its bottom an elongate opening 32 that is aligned with the corresponding elongate opening 14 of equal size in the floor. A sealing gasket 33 is placed between the filter-holder 29 and the floor to prevent penetration of water in the event of leakage in the room. Thanks to the front wall 30, which can have a height of about 5 cm, large quantities of water can accumulate on the floor before water penetrates down to the subfloor 2. A filter 34 is arranged in the filter-holder 29 to be easily detached therefrom and extends between the side walls 35, 36 and between the bottom 37 and top 38 to be sealed all around with its side sections situated outside a rigid frame 39, the frame 39 resting on an upturned edge of the opening 32 and being located closest to the front wall 30. The filter-holder is covered by a hood 40 with a width slightly greater than the filter-holder 29 so that vertical air gaps are created between the side walls 41, 42 of the hood 40 and the side walls 35, 36 of the filter-holder 29. Each air gap has a width of about 0.5-1.5 cm. The hood 40 has a downwardly-turned top flange 43 that hooks on behind the top wall 38 of the filter-holder 29, the hood 40 then being secured by screws 44 to the filter-holder 29. The inner free edges of the vertical side walls 41, 42 of the hood 40 are located a suitable distance, for instance 0.5-1.5 cm, from the wall to allow the supply flow of air to said air gap inside the hood 40 and then to the openings 32, 14 in the bottom and in the floor via the filter 34, see Figure 4.

The air-distribution device in accordance with the invention distributes the supply air along its entire length. The distribution of the ventilating air and a pressure drop occurs underneath the flooring layer 45 so that only the space 5 between the subfloor 2 and the flooring layer 45 downstream of the air-distribution device is subject to lowered pressure. With an air pressure close to that in the room 12 above, the part space between the ground sill 3 and the air-distribution device serves as an air channel 10 distributing the air up to the constriction in the form of the air gap 27 created between the air-distribution device and the subfloor 2. The significant pressure drop occurs in said air gap 27. The subfloor 2 from the air-distribution device to the pipe system for exhaust air is thus ventilated in a uniform way, the part space between the ground sill 3 and the air-distribution device being ventilated in connection with its function as a channel. The ground sill 3 and all relevant building components must be sealed to a high degree so that no undesirable air leakage arises, but the strain on the sealing capacity of the ground sill 3 when using the air-distribution device in accordance with the invention is not as great as when the significant pressure drop occurs above the flooring layer 45. The ground sill 3 is a building component that is difficult to seal, as it is in contact with the outdoor air with its changes in temperature and humidity.

The air-distribution device in accordance with the invention is easily mounted and its function is clear and simple, which increases understanding of the system.

An air-inlet device 13 in accordance with the invention replaces about 6 metres of air-pervious skirting-board and has the advantage of providing control over the descent of the air through the floor in one location. The air-inlet device 13 in accordance with the invention is mounted after carpet laying. The air-inlet device 13 is also mounted afterwards in the case of turned-up carpets, when it is rounded off in its inner lower corner to accommodate the turn-up fillet. The air-inlet device 13 does not interfere with the finishing of the flooring layer 45 as against the wall. It is easily mounted and it is clear and simple in its function. It can tolerate splashes of water and is made to withstand temporary accumulation of water on a wet floor to a level of about 5 cm. It has a washable filter that can be removed with a simple manual grip, rinsed through and re-mounted, while all skirting-boards and other building components are left in place. With the air-distribution device in accordance with the invention, thanks to its large through-flow area, it is possible to inspect and clean the air channel 10 created between the ground sill 3 and the air-distribution device in accordance with the invention. 991130 P1399SE.TP1

Claims

C A I M S

1. A device for distributing ventilation air in a ventilation system for a subfloor (2) in a building, in which a floor construction is arranged on the subfloor

(2) and comprises a plurality of joists (6) arranged at a pre-determined distance from each other and supported by a plurality of level-adjusting spacer screws (8) resting on the subfloor (2) to create a free passage (9) between the joist (6) and the subfloor (2) and a free, coherent space (5) , including said passages (9) , between the subfloor (2) and the floor construction, which space (5) forms part of said ventilation system, which further comprises a plurality of air-inlet devices (13) arranged at a pre-determined distance from each other by at least one wall (1) and each being in open communication with an opening (14) in the floor construction to said space (5) , characterized in that the device comprises an elongate plate-shaped body (16) , rigidly mounted to the joist (6a) located nearest said openings (14) for the air-inlet devices (13) , which plate body (16) includes a flat waist part (17) , a foot part (18) , a top part (19) , which foot and top parts (18, 19) extend along the long sides of the waist part (17) and are flexibly connected to the waist part (17) by way of joints (22, 23) that are parallel to each other, and a plurality of spacers (26) arranged adjoining the foot part (18) to create an air gap (27) between the foot part (18) and the subfloor (2) at the anchorage of the plate body (16) and the subfloor (2) , which plate body (16) is arranged to be anchored to said joist (6a) by means of its top part (19) with the waist part (17) sloping down towards the subfloor (2) at an acute angle and forming an obtuse angle with the foot part (18) and an obtuse or acute angle with the top part (19) , the air gap (27) being arranged to provide a pressure drop in the ventilation air passing through the same.

2. A device as claimed in claim 1 , characterized in that the plate-shaped body (16) , the joist (6a) , the adjacent wall (1) and the subfloor (2) are arranged to define between them an air channel (10) that communicates with said air gap (27) and has a pre-determined cross-sectional area, allowing the supply air from each air-inlet device (13) to flow along the entire air channel (10) and to be evenly distributed along the same, and in that the spacers (26) are of uniform height to form said air gap (27) with a virtually uniform height.

3. A device as claimed in claim 1 or 2 , characterized in that floor constructions of varying elevation relative to the subfloor (2) employ a plate body (16) having identical dimensional design in each case, the width of the waist part (17) being greater than the distance between the subfloor (2) and the underside of the joist (6a) to form an acute angle with the subfloor that is smaller than 70°, preferably smaller than 50°.

4. A device as claimed in any one of claims 1-3, characterized in that the spacers (26) are formed as integral parts of the plate body (16) on one of its sides or consist of separate pieces or constitute fixed or loose parts of the attachment elements (21) .

5. A device as claimed in any one of claims 1-4, characterized in that the air gap (27) has a vertical extension of about 2-6 mm, preferably about 3 mm.

6. A device as claimed in any one of claims 1-5, characterized in that the plate body (16) is manufactured from a plastic material, preferably polypropylene, and has a sheet thickness of at least about 1.5 mm, preferably at least 2.0 mm, and in that the width of the waist part (17) is about 8-15 cm and the widths of the foot and top parts (18, 19) are both about 1.5-2.5 cm.

7. A device as claimed in any one of claims 1-6, characterized in that the obtuse angle between the waist part (17) and the foot part (18) of the device, in its mounted state, is between about 110° and about 175°.