GB2077336A

GB2077336A - A sealing strip and a method of using the same

Info

Publication number: GB2077336A
Application number: GB8115266A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-05-22
Filing date: 1981-05-19
Publication date: 1981-12-16
Also published as: FR2483001B1; FR2483001A1; IT8121722A0; GB2077336B; ES8300172A1; ES502257A0; IT1135804B; SE8103047L; CH652443A5; NL8102250A; DK210881A

Abstract

A method of and a strip for sealing a gap between a door leaf and frame of a fire-protection door. The strip 2 consists of a core 8 and a jacket 7 which seals the core 8. The core 8 is made of a material which effervesces under the action of heat and the jacket 7 of a material which is resistive to mechanical and chemical stresses and which is limitedly elastic but which is not heat-resistant. The choice of material for the core 8 and the jacket 7 is so made that the core 8 and the jacket 7 react differently to heat. Their reaction to heat is such that initially the jacket 7 softens and the core 8 releases gases which inflate the softened jacket 7. The core 8 expands in unimpeded manner into the thus-enlarged jacket hollow space, by effervescing and, in so doing, increasing in volume so that it fills the intermediate space of the gap and seals it. The jacket 7 then melts. <IMAGE>

Description

SPECIFICATION A sealing strip and a method of using the same This invention relates to a strip for sealing a gap between a door leaf, which is in its closed position, and a door frame and to a method of using said strip to seal the gap, the strip comprising a core which effervesces under the action of heat and a jacket which encloses the core and which is connected by one outer surface to the door leaf or the frame in the region of the gap.

In known fire-retarding doors (see Federal Republic of Germany Patent No. 19 96 238), the edges of the door leaf are provided, at least at the top, with U-shaped sheet-metal strips which are bonded, for example by soldering, onto fairing plates. A sealing strip, expandable under the action of heat, is arranged between each sheetmetal strip and the end surface of the door leaf and is mounted on a sheet-metal substrate which insulates it relative to the frame, so that upon expansion of the sealing strip the sheet-metal strip is forced outwardly against the frame. Apart from the comparatively great expenditure, there is no guarantee that the sheet-metal strips will butt over the entire length of the door edge flush against the frame.In addition thereto the sealing strip, which is covered by the sheet-metal strips and which expands upon heating lies, is too protected to expand effectively upon the action of heat in the event of fire. On the contrary, it has to be feared that the expansion of the sealing strip is effected differently with a time shift over the edge of the door leaf, whereby the sheet-metal strips are perforce buckled and no longer come into a flush abutment against the frame even when the sealing strip is completely expanded all around.

More especially in the case of a sheet-metal strip which is only partially raised expansion of the sealing strip can be effected at least partially parallel to the frame and to this extent not fulfil the sealing purpose at each point.

To avoid the afore-described disadvantages, in the case of a further known fire-protection door (see Federal Republic of Germany Patent No. 24 18 290) the sealing strip is surrounded by a flattened hose sheath formed from a material which is easily meltable but not combustible, and is bonded to the door leaf or to the frame respectively. This door has the advantage that the sheathed sealing strip can be used on commercially-available frames and door leaves, in which respect the sealing strip is extensively protected against mechanical damage or chemical decomposition, and a comparatively small amount of heat is sufficient for expansion of the sealing strip without hindrance in the event of fire. In the case of this solution the flattened hose-shaped sheathing can be made, for example, of aluminium.

The hermetic enclosure of a sealing strip with an aluminium sheathing is, however, not only very expensive and complex, but also too sensitive to mechanical stresses more especially when the sheathing has a comparatively thin wall. On the other hand, a sheath which has a wall which is thick enough to withstand mechanical stresses has the disadvantage that the expansion of the sealing strip in the event of fire is hindered and the strip loses its sealing function.With increasing wall thickness of the sheathing, the sealing strip becomes in addition too protected from the heat, so leading, in extreme cases, to a completely inadequate expansion of the sealing strip and inadequate sealing of the gap between the door leaf and the frame so that, in the event of fire, smoke or even toxic gases given off by the fire, can escape into adjacent rooms despite an otherwise satisfactory function of the fireprotection door.

If the sheathing is not absolutely tight, its core material, such as sodium silicate, can, as a result of a penetration of moisture, decomposes and loses its expansibility. As a result of the sheathing of the sealing strip, there is less control over the state of the core material so that, in the case of a sealing strip which is not encapsulated in a completely moisture-tight manner, its ability to function correctly in the event of fire cannot be guaranteed.

Thus, the problem underlying the invention is to propose a method of sealing the gap between commercially-available frames and door leaves and in so doing to use a sealing strip which expands under the action of heat and which is provided with sheathing which on the one hand withstands great mechanical stresses and on the other hand offers a guarantee against a chemical decomposition of the sealing strip, without the sealing strip being so shielded from a heat by the sheathing that its expansion does not take place or only takes place in a retarded manner.

In accordance with the invention this problem is solved in that there is provided a method of sealing any gap between a door leaf, which is in its closure position, and a door frame using a strip which consists of a core, which is effervescent under the action of heat, and a jacket which encloses the core and which is connected at an outer surface to the door leaf or the frame in any gap, characterised in that the core is so sealed by the jacket, said jacket being resistive to mechanical and chemical stresses and being limitedly elastic but not heat-resistant in a completely moisture-tight manner, that upon application of heat thereto initially the jacket softens, whereupon the core releases gases which inflate the softened jacket and effervesces in unimpeded manner into space formed in the enlarged jacket and increases in volume at least to ensure the jacket fills any remaining gaps between the door leaf and the frame before the jacket is melted.

The invention also provides a strip which is arranged between a door leaf and a frame of a fire-protection door and which is fastened to end faces of the door leaf or to the sides of the frame which lie opposite these end faces, and has a core, effervescent under the action of heat, for sealing any gap between the door leaf and the door frame, characterised in that the core of the strip comprises sodium silicate and the jacket of the strip is of plastics material, for example polyvinyl chloride or a comparable material, and the ends of the jacket which is tight all around are similarly tightly sealed by plugs.

In the case of a door gap which is sealed in accordance with the method of the invention, in the event of fire the heat given off thereby initially encounters the jacket and increases the elasticity thereof. In the meantime, the temperature of the core also rises, releasing gases which lead to an increase in pressure inside the jacket, whereby the jacket is inflated. In this way the gap is completely sealed even when the gap width is non-uniform since the inflated jacket adapts positively to the cross-section of the gap. In this way even in the initial stage of a fire an absolute gap seal is ensured, so that smoke or toxic gases cannot flow through the gap between the door leaf and the frame.With an increase in the level of heat, the sealing function of the jacket is superfluous, since the core upon increasing heat from the jacket can effervesce in an unimpeded manner and thereby enlarge its volume, so that the gap is sealed solely by the effervesced core.

By fire tests it has been proved that for the sealing of a gap between a door leaf, which is in its closed position, and a frame it is in no way a matter of the heat resistance of the material with which the core is sheathed. The sheathing of the core has only the function of keeping mechanical and chemical stresses away from the core in the normal instance. In the event of fire, on the other hand, the sealing of the gap between the door leaf, which is in its closed position, and the frame is guaranteed all the better and all the more rapidly the more spontaneously the core inflates.

Therefore, the core itself initially brings about the sealing and is, in this respect, shielded as little as possible so that it is exposed to the action of heat.

A moisture-tight sealing of the core, resistive to mechanical and chemical stresses, is in the event of fire all the more effective the more rapidly and more thoroughly the core is rid of its sealing by the action of the heat.

By tests it has been proved that a sodium silicate core which is accommodated in a PVC jacket, having its ends closed off by means of a high-frequently process, is not prone to chemical decomposition, even when the sodium silicate core sealed in this way is kept under water for the periof of 20 days. A particular advantage of the PVC seal consists also in that, upon use of colour less material, the state of the core can be observed at any time.

In several fire tests it has been ascertained that the PVC seal, spontaneously softened under the first action of heat so that the core of sodium silicate effervesced in a completely unhindered manner, brought about in the shortest time a complete sealing of the gap between the door leaf and the frame.

In a further aspect of the invention advantageously the jacket has, on a side laying opposite the surface bounding the gap, slot and/or feather-shaped depressions and/or projections which extend over the length of the jacket and into which a fastening profile, mounted on the relevant surface bounding the gap, engages by means of feather-shaped and/or slot-shaped depressions and/or projections.

In the fastening region, the jacket is greater relative to the remaining jacket parts having the depressions and/or projections, so that the depressions and/or projections of the strip ensure a sufficiently secure connection of the sheathed core. This strengthening of the jacket material do not, however, hinder the expansion of the core since these reinforcements are preferably arranged laterally outside the strip-shaped core.

Therefore, spontaneous inflation of the elastic jacket over the wide side of the core strip is not hindered and thus the sealing function of the strip is guaranteed, particularly in the initial phase of a fire. Moreover, the strip of the invention has the advantage that it is particularly simple in construction and it is possible to mount the strip on commercially-available door leaves or door frames.

The equipping of a door leaf or a frame with the sealing strip is, in accordance with a further aspect of the invention, particularly facilitated in that advantageously the sealing strip is clampable in the perpendicular direction to its longitudinal extent onto the fastening strip which is bonded to the door leaf or the frame or is fixed thereto by spot welding.

In accordance with a further aspect of the invention as a preferred connection of the sealing strip to the fastening strip it is proposed to select a clip connection which is 'per se' known and proven, for example, in the case of known door profiles.

The sequence of the different reactions by virtue of the different materials of the jacket on the one hand and of the core on the other hand is ensured if preferably the ratio of the wall thickness of the jacket to the thickness of the core amounts to 1:1 to 1:6, preferably approximately 1:3 to 1:4.

Outside these ratios the risk can arise that the jacket in the event of fire inflates too late or inadequately, or else melts, before the core has filled the gap.

Good sealing results can be achieved with the t strip if the wall thickness of the jacket amounts to at least 0.5 mm and the thickness of the core amounts to at least 1.5 mm. It is to be understood that these dimensions depend on the width of the gap, but this should be selected to be at least so great that a strip with an overall thickness of 2.5 mm may be used.

In a preferred embodiment of the strip the core preferably consists of a sodium silicate strip which is rectangular in cross-section, and the jacket consists of a foil sheat of polyvinyl chloride which is filled by the core, in which respect the ends of the foil sheath are closed off with plugs which likewise consist of polyvinyl chloride. The closure of the ends of the foil sheath is equally of importance as the sheathing, so as to ensure that no chemical decompositon of the sodium silicate strip arises through penetrating air moisture.

Preferably the plug with the ends of the foil sheath forming the jacket are so connected to one another, for example by means of ultrasonic welding, that the sodium silicate core is sealed in a completely moisture-tight manner. The ultrasonic welding can be accomplished in a simple known 'per se' manner and prevents pores remaining open and also does not allow such to occur afterwards.

The invention will now be described further, by way of example, with reference to the accompanying drawing in which the single figure is a cross-section of a preferred embodiment of the strip of the invention.

In the drawing, door frame 1 produced for sheet-metal angled in Z-shaped manner carries, on that surface thereof which bounds the gap between the end faces of a door leaf (not shown) a fastening strip 2, a left-hand edge strip 3 of which is angled in the direction of the gap, whilst its right-hand edge strip has, after an appropriate angling, a bead-shaped projection 4 which is parallel to the plane of the bounding surface. The fastening strip 2 is securely connected by adhesive or spot-welding to the frame 1.

The projections 3 and 4 of the fastening strip 2 engage into correspondingly fashioned depressions 5 or 6 respectively of a jacket 7 which is made, for example, of PVC and which completely seals a strip-shaped core 8 made of, for example, sodium silicate, in which respect, for strength reasons, a plurality of glass fibre strips 9 are provided in the core 8.

Claims

1. A method of sealing any gap between a door leaf, which is in its closure position, and a door frame using a strip which consists of a core, which is effervescent under the action of heat, and a jacket which encloses the core and which is connected at an outer surface to the door leaf or the frame in any gap. characterised in that the bore is so sealed by the jacket, said jacket being resistive to mechanical and chemical stresses and being limitedly elastic but not heat-resistant in a completely moisture-tight manner, that upon application of heat thereto initially the jacket softens, whereupon the core releases gases which inflate the softened jacket and effervesces in unimpeded manner into space formed in the enlarged jacket and increases in volume at least to ensure the jacket fills any remaining gaps between the door leaf and the frame before the jacket is melted.

2. A strip which is arranged between a door leaf and a frame of a fire-protection door and which is fastened to end faces of the door leaf or to the sides of the frame which lie opposite these end faces, and has a core, effervescent under the action of heat, for sealing any gap between the door leaf and the door frame, characterised in that the core of the strip comprises sodium silicate and the jacket of the strip is of plastics material, for example polyvinyl chloride or a comparable material, and the ends of the jacket which is tight all around are similarly tightly sealed by plugs.

3. A strip as claimed in claim 2 wherein the plugs are of the same material as the jacket.

4. A strip as claimed in claim 2, or 2 and 3 characterised in that the jacket has, on a side which lies opposite the surface which bounds the gap, slot and/or feather-shaped depressions and/or projections which extend over the length of the jacket and into which a fastening profile which is mounted on the relevant surface which bounds the gap, engages by means of feather-shaped and/or slot-shaped depressions and/or projections.

5. A strip as claimed in claim 2, or in claim 2 and 3 or in claim 4, characterised in that the jacket is clampable, in the perpendicular direction to its longitudinal axis, onto the fastening profile which is fixed by bonding or spot-welding to the door leaf or to the frame.

6. A strip as claimed in any one of claims 2 to 5 characterised in that the jacket is fastened by a clip connection.

7. A strip as claimed in claim 2 characterised by perforations for the reception of rivets or screws, in which respect soffits of the perforations are continuously sealed by sleeve-shaped bridges which are welded in one piece to the jacket.

8. A strip as claimed in any one of claims 2 to 7, characterised in that, in the normal state of the strip, the ratio of the wall thickness of the jacket to the thickness of the core amounts to 1:1 to 1:6.

9. A strip as claimed in any one of claims 2 to 7 wherein the ratio of the wall thickness of the jacket to the thickness of the core amounts to 1 :3 to 1:4.

10. A strip as claimed in claim 8 characterised in that, in the normal state of the strip the wall thickness of the jacket amounts to at least 0.5 mm and thickness of the core to as least 1.5 mm.

11. A strip as claimed in any one of claims 2 to 10 characterised in that the core consists of a sodium silicate strip which is rectangular in crosssection and the jacket consists of a foil sheath of polyvinyl chloride which is filled by the core, in which respect the ends of the foil sheath are closed off by plugs which similarly consist of polyvinyl chloride.

12. A strip as claimed in claim 2 and 1 1, characterised in that the plugs with the ends of the foil sheat which forms the jacket are so connected to one another, for example by means of ultrasonic welding, that the sodium silicate strip which forms the core is sealed in a completely moisture-tight manner.

13. A strip for sealing any gap between a door leaf and a door frame substantially as hereinbefore described with reference to and or illustrated in the accompanying drawings.

14. A method of sealing any gap between a door leaf and a door frame substantially as hereinbefore described with reference to the accompanying drawings.