The subject of this invention is an expanding, fire-proof seal containing a substance which expands when, because of a fire, the ambient temperature increases, and a method of making of the expanding, fire-proof seal.

There are expanding, fire-proof seals known as having the form of a strip containing a substance which swells, when the ambient temperature increases. Such expanding, fire-proof seals are fastened around the door frame by means of nails or glue. The seal is then secured against mechanical damages and penetration of water and carbon dioxide from the atmosphere.

Also expanding, fire-proof seals are known which are made in the form of a strip containing a swelling substance and having its both sides covered with aluminium foil, constituting a partial protection against mechanical damages and noxious atmospheric agents. The seal of this kind is fastened to the door frame in the same way as that not covered with aluminium foil, and then its surface is secured by being coated with a layer of paint.

Expanding, fire-proof seals are mounted round the frames of fire doors which are supposed to serve both as smoke and flame barriers in the staircases of buildings, for example, hotels, offices etc., and in such rooms as, for example, boiler-room. Fire doors serving as barriers should prevent fire from spreading.

The known strip-shaped expanding, fire-proof seals are not elastic and, at low ambient temperatures, they do not fill the clearance between the door and its frame so as to prevent penetration of smoke. The swelling substance which the seals are made of begins to expand only when ambient temperature exceeds 100 ° C.

The basic fault of the known expanding seal is its lack of elasticity, which, at the normal ambient temperature, causes it not to be smoke-proof and not to prevent smoke from getting through doors sealed with this seal.

The seal becomes smoke-proof only after the ambient temperature exceeds 100 ° C i. e. the value at which the known expanding seal begins to slowly increase its volume. The seal, expanding in accordance with further increase in the temperature, completely fills the clearance between the fire door and its frame, only when the temperature reaches 180 ° C.

In order that the faults of the known expanding seals might be removed a design has been worked out according to the present invention, for a seal which has adequate elasticity at temperatures as low as the normal ambient temperature and effectively fills the clearance between the door and its frame, causing a fire door to become smoke-proof at the very moment of its closing, at the normal ambient temperature.

The expanding seal according to the invention is characterized by the fact, that an expanding core which contains a swelling substance and is shaped, preferably as a strip of a rectangular cross-section, is placed in a protective jacket, preferably of a closed profile, and having the form of a pipe, made of thermoshrinkabie plastic. Spread on a part off the outer surface of the protective jacket, there is a layer of an adhesive substance containing glue which, in turn, has its outer side covered with a protective strip made, preferably of paper or plastic film. The expanding seal, characterized by the fact that its expanding core, containing a swelling substance and having the shape, preferably of a rectangular cross-section strip is, together with an elastic spacer having the form, preferably of a strip made of foamed plastic or rubber, placed in the protective jacket, preferably of a closed profile and having the shape of a pipe, made of thermoshrinkabie plastic. Spread on a part of the outer surface of the protective jacket is an adhesive layer which, in turn, has its outer side covered with a protective strip made, preferably of paper or plastic film.

The method of making of the expanding, fire-proof seal according to the present invention is characterized by the fact, that the expanding core containing a swelling substance, and having the shape, preferably of a rectangular cross-section strip, is inserted into the protective jacket having the shape, preferably of a pipe made of thermoshrinkabie plastic. The area of the cross-section of the expanding core is smaller than the area ofthe inner cross-section of the protection jacket. A part of the outer surface of the protective jacket wall is heated up to the temperature of 200 ° C in order that a part of the perimeter of the protective jacket wall may shrink under the influence of temperature. Then the adhesiveiayer is applied onto the

shrunk part of the protective jacked wall and covered with the protective strip made, preferably of paper or plastic film.

The expanding seal according to the present invention has high elasticity and effectively fills up clearances in fire doors, cousing them to be smoke-proof at temperatures as low as the normal ambient temperature. The increase in the ambient temperature exceeding 100 ° C makes the expanding core start to swell. As the temperature continues to increase, because of a fire, the volume of the expanding core increases so much that it bursts the protective jacket and fills up the clearance between the door and its frame. The swelling substance of the expanding core increases its volume almost seven times and remains fire-proof up to the temperature of 1100 ° C.

The subject of the present invention is presented, as an example of its embodiment, by the drawing, in which: Fig. 1 shows the cross-section of the seal, Fig. 2 - the cross-section of the seal whose expanding core is provided with aluminium foil shields on both sides, Fig. 3 - the cross section of the seal containing the expanding core and the elastic spacer, Fig. 4 - the cross-section of the seal containing the expanding core with its shields and the elastic spacer, Fig. 5 - the cross-section of the seal, distorted by a slightly increased temperature, Fig. 6 - the cross-section of the seal, distorted at a temperature considerably increased, Fig. 7 - the cross-section of the protective jacket with the expanding core inside, before the partial shrinking of the protective jacket, Fig. 8 - the cross-section of the seal, undergoing the operation of partial shrinking of its protective jacket, Fig. 9 - the cross-section of the seal, with the adhesive layer applied.

In Fig. 1 the expanding seal has been presented, for example, with the expanding core 1 containing a swelling substance and having the shape, preferably of a rectangular cross-section strip. The expanding core 1 is placed in the protective jacket 2 which has the form, preferably of a thermoshrinkabie plastic pipe of a closed profile. On a part of the outer surface of the protective jacket 2, in the place where the wail has been partially shrunk, the adhesive layer 3, containing glue is applied. The outer side of the layer 3 is covered with the protective strip 4 made, preferably of paper or plastic film.

In Fig. 2 the expanding seal has been presented, for example with the design of its expanding core 1 changed so, that its both sides are covered with aluminium foil shields 6.

in Fig. 3 the expanding seal has been presented, for example with the expanding core 1 containing a swelling substance and having the form of a rectangular cross-section strip which, together with the elastic spacer 5 having the shape, preferably of a strip made of foamed plastic or rubber, is placed in the protective jacket 2 which has the shape, preferably of a thermoshrinkabie plastic pipe of a closed profile. On the outer surface of the protective jacket 2, in the place where a part of the wall of the protective jacket 2 has been preliminarily shrunk, the adhesive layer 3 containing glue is spread and its outer side is, in turn, covered with the protective strip 4 made, preferably of paper or plastic film.

Shown in an exemplary embodiment in Fig. 4, is the expanding seal with the elastic spacer 5 placed in the thermoshrinkabie plastic protective jacket 2, together with the expanding core 1 whose both sides are covered with shields 6 made of aluminium foil. Spread on the outer surface of the thermoshrinkabie plastic protective jacket 2, in the place where a part of the protective jacket 2 wall has been preliminarily shrunk, is the adhesive layer 3, whose outer side is covered with the protective strip 4 made of paper or plastic film.

An exemplary sequence of operation for the method of making of the expanding, fire-proof seal has been presented in Fig. 7, Fig. 8 and Fig. 9, where: in Fig. 7 the expanding core 1 having the shape of a rectangular cross-section strip containing a swelling substance, is inserted into the protective jacket 2 which has the shape of a thermoshrinkabie plastic pipe of a closed profile. The area of the expanding core 1 cross-section is smaller than the inner area ofthe cross-section of the protective jacket 2. Then, as it has been shown in Fig. 8, a part of the outer surface of the protective jacket 2 wall is heated up to a temperature of about 200 ° C so that it will partially shrink i. e. that the perimeter of the wall of the protective jacket 2 will decrease. The shrinking heat treatment consists, for example, in heating of the wall of the thermoshrinkabie protective jacket 2 with flame 7 from a burner 8, or in a stream of hot air, etc. Then, as it has been shown in Fig. 9, the adhesive layer 3 is applied onto the shrunk part of the wall of the protective jacket 2, and covered with the protective strip 4 made, for example, of paper or plastic film.

When the expanding, fire-proof seal, placed in the clearance between a door and its frame is heated up to a temperature between 180 and 200 ° C, because of a fire, its volume begins to increase due to the swelling ofthe expanding core 1.

At the beginning, the swelling expanding core 1, confined inside the protective jacket 2, changes its shape, as shown in Fig. 5, and then, when the ambient temperature exceeds 200 ° C, the protective jacket 2 melts and bursts and, as the temperature continues to increase, the expanding core 1, increasing its volume, fills more and more of space between the door and its frame, which has been shown in Fig. 6. The volume of the expanding core increases about seven times, and the core itself remains indestructible up to a temperature about 1100 ° C.