KERVEFORS AAKE (SE)
| EP0664532A1 | 1995-07-26 | |||
| US4818843A | 1989-04-04 | |||
| GB2315683A | 1998-02-11 |
| 1. | A smoke or mist generator intended to be mounted into equipment that is intended to protect from observation or to limit view and in this way prevent or obstruct impermissible access to a certain area or premises, by activating on a signal from an alarm system or another signal one or several smoke or mist generators in the equipment that is or are connected to a supply system for fluid, characterised in that the smoke or mist generator comprises a container (1) containing a porous substance (2), arranged to absorb the fluid that is led or that is present in association with the porous substance, and by a heatproducing unit (3,9), which is normally inactive, but which can be activated from the said alarm system or other signal, for heating a part or all of the fluid that has been absorbed by the porous substance, such that it is pressed out through a nozzle (4) and forms the mist or smoke. |
| 2. | The smoke or mist generator according to claim 1, characterised in that the supply of fluid is arranged to be immediately activated or activated soon after the arrival of the signal such that consumed fluid is continuously replaced and that mist or smoke is continuously generated. |
| 3. | The smoke or mist generator according to any one of the preceding claims, characterised in that the heatproducing unit comprises an internally wound resistance wire (3) arranged to heat a surface or zone that lies next to the surface of the porous substance (2) and in this way vaporise the fluid. |
| 4. | The smoke or mist generator according to any one of the preceding claims, characterised in that the porous substance comprises a blanket, preferably a ceramic blanket, with which the container (1) is internally clothed. |
| 5. | The smoke or mist generator according to claim 4, characterised in that the heatproducing unit comprises a resistance wire internally woven into the blanket. |
| 6. | The smoke or mist generator according to any one of the preceding claims, characterised in that the container comprises an outlet nozzle (4) or pressure controlled outlet valve, and in that fluid is arranged to be sprayed into the container under pressure. |
| 7. | The smoke or mist generator according to any one of the preceding claims, characterised in that the porous substance (2) is saturated and/or connected to a tank (7) of the fluid. |
| 8. | The smoke or mist generator according to any one of the preceding claims, characterised in that the fluid in the porous substance (2) is arranged to be heated through a part or the whole of the porous substance being made electrically conductive and being arranged to be heated by direct connection to a power supply (9). |
| 9. | The smoke or mist generator according to any one of claims 17, characterised in that the fluid in the porous substance is arranged to be heated through parts or the whole of the porous substance (2) being heated by inductive heating. |
| 10. | The smoke or mist generator according to any one of claims 17, characterised in that the fluid in the porous substance is arranged to be heated through heating by microwaves. |
In particular, the invention concerns a smoke generator that can be used when mounted in protective equipment to protect a region or premises from unauthorised or impermissible access and to hinder items or goods from being taken by unauthorised personnel, and goods being stolen from, for example, shops. The protection functions by a white or grey/white smoke or mist being sprayed out into the premises when a signal is given by, for example, an alarm device, which prevents persons from finding goods or finding the way to valuables or cash.
THE PRIOR ART The technology for producing smoke or mist through the heating of a special fluid is known and is used not only in film and theatre, but also as intrusion protection. The type of smoke-fluid that is used in the present invention is commonly used in theatre, in films and at rock concerts. It is harmless when inhaled and in the event of contact with the skin or eyes, and it does not leave any powder residue, which otherwise may give rise to staining on textiles, etc. The fluid and the smoke or mist are essentially free of odour. Fluids of this nature based on alcohol are sold under such names as"Rosco"and"Heavy Smoke".
Heating normally takes place by spraying the fluid onto a hot metal surface, which is electrically heated.
The technology for producing smoke or mist in order to prevent intrusion is known and it is normal to use equipment that is pre-heated to the temperature required, after which the fluid is pumped to the pre-heated surface when the start signal or alarm signal arrives. In another embodiment, electrical wires in a glass tube are heated in the event of an alarm, after which the fluid is released from a pressurised container.
In the context of the theatre, a metal surface is electrically heated, after which the fluid is pumped onto the surface. Equipment for intrusion protection normally has a metal surface that is held pre-heated to a high temperature. The equipment is thus held at a constant high temperature, prepared for the generation of smoke.
BRIEF DESCRIPTION OF THE DRAWINGS The smoke or mist generator according to Figure 1 comprises a container (1) with an inner porous filling (2) in the form of blanket or a spongy mass with a coil (3) wound against the porous surface. A nozzle (5) is located at one end of the container, connected by a pipe or tube to a pump (6), which is, in turn, connected to a container (7). The coil (3) is electrically heated from a power supply (9). An outlet nozzle or outlet valve (4) is located at the end of the container, out of which the smoke formed can flow. The pressure in the container is controlled by, for example, a specially designed outlet nozzle or by a valve with spring-loaded stopper.
DESCRIPTION OF EMBODIMENTS The smoke or mist generator can be incorporated into a complete system for smoke generation, for example, an intrusion alarm with an incorporated system for smoke generation.
The smoke or mist generator according to Figure 1 comprises a closed container (1) with a tube-formed connection with a nozzle (5) at one end and an outlet valve (4) at the second end. The outlet valve can be designed in order to regulate or control the pressure in the container and/or in the outlet in the form of a spring-loaded stopper, which rests in a seating or by a specially designed nozzle.
A porous surface (2), or a blanket or sponge, is located in the container (1), and it can absorb the fluid, which is present in the container or fed into the container (1).
A heating means in the form of a electrical coil (3) or other heating element is located
against or in connection with the porous surface.
Fluid is fed or sprayed into the container and is absorbed by the porous blanket (2) or sponge. The electrical coil (3) lies in contact with the blanket and heats the fluid in the layer closest to it. The fluid is converted to vapour at a certain temperature, which vapour then condenses to a white smoke when the temperature falls. The vapour starts to pass out through the outlet valve, on which the pressure and the temperature of the vapour fall. The pressure during the process is controlled by a pre-set valve or by the design of the outlet nozzle being such that a certain pressure interval is achieved during the process. The vapour condenses to a white or grey/white mist or smoke when the temperature falls.
When the unit is activated for the production of smoke or mist, fluid is supplied and is absorbed by the porous substance. The part of the fluid that lies next to the heating element is at the same time vaporised and the vapour can then pass out through a nozzle or outlet valve. Smoke or mist can be continuously generated by continuously supplying fluid to the porous part of the container while at the same time vaporising the fluid that is absorbed by the region around the heating means. Fluid is vaporised in the region around the heating element and then lead out via the valve.
The smoke generator according to Figure 2 can also be constructed from a container (1) with an internal rod-formed porous part (2) with an external coil (3). Fluid is continuously supplied in the centre of the rod-formed part and is absorbed outwards towards the perimeter and the heating element.
The smoke generator according to Figure 3 can be constructed from a container (1) with an internal tube-formed porous part (2) with an internal or an external coil (3). Fluid is supplied in this case from the outer surface or the inner surface of the tube-formed porous part.
The smoke generator according to Figure 4 comprises a container with a porous substance at the bottom and a heating means on its upper surface. The porous substance at the bottom of the container is maintained permanently dampened by the fluid via a tube connection to a neighbouring vessel. As an alternative, the container may be made sufficiently large to
hold all fluid in or under the porous substance. The fluid is absorbed towards the heating element by capillary action. The fluid is heated in the upper part, it vaporises and becomes super-heated. Vapour is pressed out through the specially designed or pressure-controlled nozzle by the vapour pressure.
The heating element in the smoke generator may comprise resistance wire or an insulated heating element or a material that is inductively heated from an externally placed coil or from microwaves.