IMPROVEMENTS IN OR RELATING TO SMOKE AND FIRE BARRIERS

Abstract: A smoke and fire barrier for installation in or over an opening and operable selectively to prevent the passage therethrough of smoke, comprises a stationary grill having apertures through which air can flow and sealing means operable to seal the apertures against the passage of smoke therethrough. The sealing means takes the form of a sliding plate which is positioned adjacent the grill and has apertures which register with the apertures of the grill when the smoke barrier is in an open configuration and lands between the apertures which register with the apertures of the grill when the smoke barrier is in closed configuration. The plate is slidable horizontally relative to the grill automatically in response to the presence of smoke and/or heat between a first position in which the smoke barrier is in its open configuration and a second position in which the smoke barrier is in its closed configuration.

Description: Improvements in or Relating to Smoke and Fire Barriers This invention relates to a smoke and fire barrier for preventing the passage of smoke through an opening such as an opening in a wall or panel, or through ducting, e.g. ducting of the type used in ventilation or air-conditioning systems. A smoke barrier is disclosed in our earlier Application No. 921 5687.6 which comprises an apertured plate movable vertically relative to a complementary apertured grill to open and close the air openings of the grill. The plate is held by an electromagnet or solenoid in its open position and falls under gravity to its closed position when the electromagnet or solenoid is rendered inactive in the event of fire or smoke. One disadvantage of this earlier barrier is the requirement to hold the vertically movable plate in its other unsupported position while the grill is open. The present invention is an improvement to this smoke barrier. In a first aspect the invention provides a smoke and fire barrier for installation in or over an opening and operable selectively to prevent the passage therethrough of smoke, the smoke barrier comprising a stationary grill having apertures through which air can flow and sealing means operable to seal the apertures against the passage of smoke therethrough, the sealing means being in the form of a sliding plate positioned adjacent the grill and having apertures which register with the apertures of the grill when the smoke barrier is in an open configuration and lands between the apertures which register with the apertures of the grill when the smoke barrier is in closed configuration, the plate being slidable horizontally relative to the grill automatically in response to the presence of smoke and/or heat between a first position in which the smoke barrier is in its open configuration and a second position in which the smoke barrier is in its closed configuration. In a preferred embodiment, the sealing means is operable in response to the detection of smoke and/or heat by an associated detection means such as a smoke detector. For example, a solenoid can be provided which is de-energised in response to a signal from the detection means. In this arrangement, the solenoid plunger engages the sliding plate in the absence of smoke or fire, to hold the plate in its "open" position against the action of a spring, but which upon receipt of a signal from the detection means to de-energise the solenoid retracts to cause the plate to move to its sealing or "closed" position under the action of the spring. A latch may be provided to hold the sliding plate against the action of the spring when the smoke barrier is in its open position. This latch may comprise an electromagnet. The lands of the sliding plate can comprise or have disposed thereon one or more sealing elements for sealing the apertures in the stationary grill. In one embodiment, the sealing element(s) can take the form of brush seals or blade seals, for example blade seals formed from an elastomeric material such as neoprene. In another embodiment, the sealing element can comprise a portion (e.g. a strip) of an intumescent material. The intumescent material can optionally be coated, treated or otherwise covered by a covering material or covering layer. For example, the intumescent material may have a smooth facing material laminated thereto. The intumescent material can be bonded to the sliding plate, for example by means of an adhesive, or it can be held within a holder or other mounting means, for example a holder formed of plastics material. An advantage of using an intumescent material as the sealing element is that in a fire situation, the intumescent agent expands to provide an even more secure seal against the passage of smoke through the grill. The plate preferably includes wheels which track within horizontally extending guideways of the grill or a frame therefore. For plates which are intended to lie in a generally vertical plane, wheels need only be provided along the lowermost edge of the plate. For plates which are intended to lie in a generally horizontal plane, however wheels may be provided along each side edge of the plate. It is to be understood that the term "signal" as used herein includes the simple case wherein an applied voltage between the detection means and the latch is cut off. The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings, in which:- Figure 1 is a front elevation of a smoke barrier according to the invention; Figure 2 is a sectional side elevation along line l-l of Figure 1 ; and Figure 3 is a front elevation of the barrier shown in Figure 1 with its cover removed. Turning now to the drawings, it can be seen that the smoke barrier comprises an outer grill 1 having a plurality of rows of elongate slots 2 through which air can normally pass. In Figure 1 , the elongate slots 2 are shown as being sealed by brush seals 3, the tips of which protrude slightly through the slots 2. When in use, the grill is placed in or over an opening in a door, ceiling or wall and is fixed by means of suitable securing elements such as screws (not shown). Connected to the rear of grill 1 is a sliding plate 4 which is held in contact with the grill 1 by means of screws located in slots of the sliding plate 4. The plate 4 is slidable to and fro in substantially horizontal directions with respect to grill 1 by virtue of the slots. The sliding plate 4 is provided with elongate apertures 6 which allow the passage of air therethrough. Along one edge of each aperture 2, the grill has outstanding flanges 8. Affixed to the sliding plate 4 between each pair of adjacent elongate apertures 6, are the brush seals 3 (depicted as cross-hatched areas in Figure 1 ), the filaments or bristles of which are generally directed outwardly of the plate. The brush seals 3 conveniently are affixed to the sliding plate 4 by means of a suitable adhesive. As an alternative to the brush seals 1 1 , blade seals, eg formed of a resilient elastomeric material such as neoprene can be used. Affixed to the inner surface of a side wall of the inner frame 9 of the grill 1 is a solenoid 10 which operates from a 12v or 24v power supply (not shown) and whose plunger 1 1 is attached to or bears against the plate 4. A coil spring 12 is connected at one end to the grill frame 9 and at its other end to the plate 4. An electro magnet 14 is mounted on the grill and co¬ operates with a latch 17 on the plate. When energised, the solenoid plunger engages the plate to hold it in its open position against the action of the coil spring 12 with the assistance of the electro magnet 14. The plate 7 has wheels 1 6 which run in guideways 17 of the grill frame 9 for ease of movement. The plate illustrated is intended to be mounted in a vertical door or wall. For plates which are intended to be flat (e.g. when positioned in a ceiling) wheels may be provided along each side edge of the plate. In use, when the solenoid and electro magnet are energised the sliding plate 4 is held in its open position in which the slots 2 in the grill 1 are aligned with the apertures 6 in the sliding plate 4 to allow air to flow through the grill. If the solenoid is de-energised, for example in response to the detection of smoke by an associated smoke detector the solenoid plunger 1 1 moves out of engagement with the plate 4 to cause it to be propelled by the coil spring 1 2 to its closed position in which the brush seals 1 1 come into register with and seal the elongate slots 2 against smoke penetration. Instead of the brush seal 1 1 , a blade seal can be used, but in one preferred alternative embodiment, a strip of intumescent material is used as the sealing element in place of the brush seal. The strip of intumescent material can be a plain uncoated strip of intumescent material or it can be provided with a generally smooth facing strip which can be, for example, laminated to the intumescent material. The intumescent material can be bonded to the sliding plate 4 by means of an adhesive, or it can be held within a suitably shaped holder formed from, for example, a plastics material. In order to reset the device, the solenoid and electro magnet are re-energised and the sliding plate 4 returns against the action of the spring into its open position. A switch, not shown, is advantageously provided which is actuated by the sliding plate as it is moved into the open position. The switch, when actuated, cuts off the power supply to the solenoid thereby leaving the electromagnet to hold the sliding plate in place against the restoring force of the coil spring. Thus, the power required to hold the sliding plate in the open position of the barrier is significantly reduced. The smoke barrier of the invention may optionally incorporate a fire barrier, including an intumescent block grill of the type described in our British Patent Application No. 9207659.5. In this illustrated embodiment, the intumescent mixture is encased in aluminium foil in order to prevent moisture penetration which could adversely affectthe intumescent properties of the grill. In the case of the smoke barrier device being subject to the elevated temperatures associated with fire, the grill intumesces and rapidly swells to fill completely the width of the opening in or over which the smoke barrier device is located. Instead of, or in addition to, the block grill, a double plate arrangement coated with or containing intumescent material can be employed. The smoke barriers of the type illustrated can be used to cover ducting in inter alia fire walls, doors, glazed partitions, windows or ceilings, and can be provided with deep side, upper and lower walls to enable them to act as covers for ventilation fans. It will be appreciated that the foregoing is merely exemplary of smoke and fire barriers in accordance with the invention and that modifications can readily be made thereto without departing from the scope of the claims appended hereto.

Claims: CLAIMS 1 . A smoke and fire barrier for installation in or over an opening and operable selectively to prevent the passage therethrough of smoke, the smoke barrier comprising a stationary grill having apertures through which air can flow and sealing means operable to seal the apertures against the passage of smoke therethrough, the sealing means being in the form of a sliding plate positioned adjacent the grill and having apertures which register with the apertures of the grill when the smoke barrier is in an open configuration and lands between the apertures which register with the apertures of the grill when the smoke barrier is in closed configuration, the plate being slidable horizontally relative to the grill automatically in response to the presence of smoke and/or heat between a first position in which the smoke barrier is in its open configuration and a second position in which the smoke barrier is in its closed configuration. 2. A barrier as claimed in claim 1 wherein the sealing means is operable in response to the detection of smoke and/or heat by an associated detection means such as a smoke detector. 3. A barrier as claimed in claim 2 wherein a solenoid is provided which is de-energised in response to a signal from the detection means. 4. A barrier as claimed in claim 3 wherein the solenoid plunger engages the sliding plate in the absence of smoke or fire, to hold the plate in its "open" position against the action of a spring, but which upon receipt of a signal from the detection means to de-energise the solenoid retracts to cause the plate to move to its sealing or "closed" position under the action of the spring. 5. A barrier as claimed in any one of the preceding claims wherein a latch is provided to hold the sliding plate against the action of the spring when the smoke barrier is in its open position. 6. A barrier as claimed in claim 5 wherein the latch comprises an electromagnet. 7. A barrier as claimed in any one of the preceding claims wherein the plate includes wheels which track within horizontally extending guideways of the grill or a frame therefore. 8. A barrier as claimed in claim 7 wherein wheels are provided along the lowermost edge of the plate. 9. A barrier as claimed in claim 7 or claim 8 wherein wheels are provided along each side edge of the plate. 10. A barrier as claimed in any one of the preceding claims wherein the lands of the sliding plate comprise or have disposed thereon one or more sealing elements which seal the apertures in the grill when the when the smoke barrier is in closed configuration. 1 1 . A barrier as claimed in claim 10 wherein the sealing element or elements is or are selected from blade seals and brush seals. 12. A barrier as claimed in claim 10 wherein the or each sealing element comprises a portion of intumescent material. 1 3. A barrier as claimed in claim 12 wherein the intumescent material is provided with a covering or facing layer. 14. A barrier according to claim 1 3 wherein the covering or facing layer is a smooth surfaced facing which is laminated to the intumescent material. 15. A smoke and fire barrier substantially as herein described and as described with reference to Figures 1 to 3 of the accompanying drawings.

Inventors: WARD DEREK ALFRED, WARD, DEREK, ALFRED
Applicants: ENVIRONMENTAL SEALS LTD, ENVIRONMENTAL SEALS LIMITED
Application year: 1997
Main classification: A62C2
IPC codes: A62C2