GB2305917A

GB2305917A - A composition for testing a smoke dectector

Info

Publication number: GB2305917A
Application number: GB9620335A
Authority: GB
Inventors: David James Gunn; William Douglas
Original assignee: 21ST CENTURY INNOVATIONS Ltd; GREENHILL CHEM PROD Ltd
Current assignee: 21ST CENTURY INNOVATIONS Ltd; GREENHILL CHEM PROD Ltd
Priority date: 1995-10-03
Filing date: 1996-09-30
Publication date: 1997-04-23
Anticipated expiration: 2016-09-30
Also published as: GB9620335D0; GB2305917B

Abstract

A composition for testing a smoke detector comprises a carrier and one or more siloxanes. The siloxanes may be selected from polydimethylcyclosiloxanes and polyphenylmethylsiloxanes. The carrier may comprise a propellant to alter the composition to be applied as an aerosol spray.

Description

A Composition for Testing a Smoke Detector This invention relates to compositions for testing smoke detectors.

Smoke alarms or detectors can be tested for their functioning by pushing a button on the alarm. This verifies power availability and alarm operation. It does not test the sensor.

Testing the sensor involves spraying a simulated smoke composition onto the sensor. There are two disadvantages to present simulated smoke compositions. The first is that the simulations based on oils tend to be cumulative and build up in the sensor, thereby reducing its effectiveness. The second is that those simulators which comprise phthalates or their esters can have a similar cumulative effect and also have an adverse effect on the plastics and rubbers used in the construction of the detector.

According to this invention there is provided a composition for testing a smoke detector, comprising a carrier and an active component, the active component comprising one or more siloxanes.

The active component may comprise one or more methyl siloxanes, preferably selected from the group comprising polydimethyl cyclosiloxanes and polyphenylmethyl siloxanes. Advantageously, the siloxanes are volatile to evaporate from the detector. The polydimethyl cyclosiloxanes are preferably of the hexamer and/or pentamer forms.

The methyl siloxanes may comprise methicones preferably dimethicone and/or cyclomethicone.

In one embodiment, the active component consists of volatile polydimethyl cyclosiloxanes, which suitably provide rapid dissipation of the siloxanes after deposition on the detector. In another embodiment, the active component comprises a major proportion of polydimethyl cyclosiloxanes and a minor proportion of polyphenylmethyl siloxanes to reduce the rate of dissipation.

An advantage of the above two described embodiments is that it is possible to use them to test a wide range of detectors without giving any of the problems associated with residual material or tackiness in drying.

In a first embodiment the active component is preferably present in the composition in a proportion in the range of 0.4 to 10 % wt/wt, more preferably, substantially 1.2% wt/wt. The active component may comprise 0.5 to 10% wt/wt of polydimethyl cyclosiloxanes, more preferably substantially 0.9% wt/wt. Also the active component preferably comprises 0.1 to 5% wt/wt polyphenylmethyl siloxane, more preferably substantially 0.3 % wt/wt.

In a second embodiment the active component is present in the composition in a proportion in the range of 1 to 10 % wt/wt, preferably substantially 4% wt/wt. In this embodiment the active component may comprise 1 to 10% wt/wt polydimethyl cyclosilxane, preferably substantially 3% wt/wt. Also, the active ingredient may comprise 0.3 to 5% wt/wt polyphenylmethyl siloxane, preferably substantially 1% wt/wt.

The carrier may comprise a solvent or diluent in which the active component is dissolved or suspended. The solvent may be a branched chain hydrocarbon solvent, which may comprise C7-C18 preferably comprising C7 C13, more preferably C9-C1;). The use of the solvent has the advantage that it improves the uniformity of particle size distribution in the composition. Such use has the further advantage, combined with a volatile siloxane, that the composition functions as a cleaner to solubilise oils and other organic matter adhering to the detector.

In the first embodiment the solvent may be present in the composition in a proportion in the range of 0.1 to 10% wt/wt, preferably substantially 0.3% wt/wt. In the second embodiment the solvent may be present in the composition in a proportion in the range of 0.1 to 10% wt/wt, preferably of substantially 1% wt/wt.

The carrier preferably also includes a propellant to enable the composition to be applied to the detector as an aerosol spray. In the first embodiment the propellant may be a fluorocarbon, desirably a tetrafluorocarbon. The tetrafluorocarbon may be a tetrafluoroethane, preferably 1, 1, 1, 2 tetrafluoroethane. In the second embodiment the propellant may be a C3-C5 alkane. Preferably the propellant comprises one or more of propane, n-butane and isobutane.

In the first embodiment, the propellant is preferably present in a proportion in the range of 80 to 99.9% wt/wt, more preferably substantially 98.5% wt/wt.

In the second embodiment, the propellant is preferably present in the range of v S to 99% wt/wt, more preferably substantially 95% wt/wt. The isobutane is preferably present in the range of 10 to 25% wt/wt, more preferably substantially 14% wt/wt. The n-butane is preferably present in the range of 25 to 55% wt/wt, more preferably substantially 29% wt/wt. The propane is preferably present in the range of 20 to 60% wt/wt, more preferably substantially 32% wt/wt.

Embodiments of the invention will now be described by way of example only.

Example I A composition comprising the following components was prepared: substantially 0.3% wt/wt of polyphenylmethyl siloxane; substantially 0.9% wt/wt of polydimethyl cyclosiloxane; substantially 0.30m wt/wt of a branched chain hydrocarbon solvent (predominantly C9-C15 based); and substantially 98.5% wt/wt 1,1,1,2 tetrafluoroethane sold under the trade name HFA 134a.

The composition was applied to a smoke detector using an aerosol spray and gave good results in actuating the detector. Furthermore, the composition evaporated quickly from the detector after actuation thereof to leave little or no residue thereon.

The composition described in Example 1 is of particular suitability in places were it is of importance that the composition is non-flammable.

Example II A composition comprising the following components was prepared: substantially 1% wt/wt polyphenylmethylsiloxane; substantially 3% wt/wt polydimethylcyclosiloxane; and substantially 1% wt/wt of a branched chain hydrocarbon solvent (predominantly C9-C15 based).

These components were pre-mixed.

A propellant consisting of the following components was then blended with the aforementioned pre-mixture: substantially 14% wt/wt isobutane; substantially 29% wt/wt n-butane; and substantially 52% wt/wt propane.

The application of the composition to the detector was by aerosol spray and the composition gave good results in activating the detector. Furthermore, the composition evaporated quickly from the detector after actuation thereof to leave little or no residue thereon.

The composition described in Example II is of suitability in places where flammable materials can be used.

In the above two examples the generic/trade names of polyphenylmethylsiloxane, polydimethylcyclosiloxane and the hydrocarbon solvent are as follows: the polyphenylmethylsiloxane has generic/trade names of phenyldimethicone/silicone DC 256; the polydimethylcyclosiloxane has generic/trade names of (volatile) cyclomethicone/silicone DC 246; and the hydrocarbon solvent has generic/trade names of isoparaffin/isopar K.

Various modifications can be made without departing from the scope of the invention.

Claims

Claims:

1. A composition for testing a smoke detector comprising a carrier and an active component, the active component comprising one or more siloxanes.

2. A composition according to Claim 1, wherein the active component comprises one or more methylsiloxanes.

3. A composition according to Claim 2, wherein the methyl siloxanes are selected from the group comprising polydimethylcyclosiloxanes and polyphenylmethylsiloxanes.

4. A composition according to Claim 3, wherein the polydimethylcyclosiloxanes are of the hexamer and/or pentamer forms.

5. A composition according to any preceding Claim, wherein the active component consists of substantially only volatile polydimethylcyclosiloxanes.

6. A composition according to any of Claims 1 to 4, wherein the active component comprises a major proportion of polydimethylcyclosiloxane and a minor component of polyphenylmethylsiloxane.

7. A component according to any preceding Claim, wherein the active component is present in the composition in a proportion in the range of 0.4 to 10 % urt/wt.

8. A composition according to Claim 7, wherein the active component is present in the composition in a proportion of substantially 1.2% wt/wt.

9. A composition according to Claim 7 or 8, wherein the active component comprises 0.5 to 10% wt/wt of polydimethylcyclosiloxane.

10. A composition according to Claim 9, wherein the active component comprises substantially 0.9% wt/wt polydimethylcyclosiloxane.

11. A composition according to any of Claims 7 to 10, wherein the active component comprises 0.1 to 5% wt/wt polyphenylmethylsiloxane.

12. A composition according to Claim 11, wherein the active component comprises substantially 0.3 % wt/wt.

13. A composition according to any of Claims 1 to 6, wherein the active component is present in the composition in a proportion in the range of 1 to 10% wt/wt.

14. A composition according to Claim 13, wherein the active component is present in the composition in a proportion of substantially 4% wt/wt.

15. A composition according to Claim 13 or 14, wherein the active component comprises 1 to 10% wt/wt polydimethylcyclosiloxane.

16. A composition according to Claim 15, wherein the active component comprises substantially 3% wt/wt polydimethylcyclosiloxane.

17. A composition according to any of Claims 13 to 16, wherein the active component comprises 0,3 to 5% wt/wt polyphenylmethylsiloxane.

18. A composition according to Claim 17, wherein the active component comprises substantially 1% wt/wt polyphenylmethylsiloxane.

19. A composition according to any preceding Claim, wherein the carrier comprises a solvent or diluent in which the active component is dissolved or suspended, the solvent or diluent being a branched chain hydrocarbon.

20. A composition according to Claim 19, wherein the solvent or diluentis present in the composition in a proportion in the range of 0.1 to 10% wt/wt.

21. A composition according to Claim 20, wherein the solvent of diluent is present in the composition in a proportion of substantially 0.3% wt/wt.

22. A composition according to Claim 19, wherein the solvent or diluent is present in the composition in a proportion in the range of 0.1 to 10% wt/wt.

23. A composition according to Claim 22, wherein the solvent or diluentis present in the composition in a proportion of substantially 1% wt/wt.

24. A composition according to any of the preceding Claims, wherein the carrier comprises a propellant to enable the composition to be applied as an aerosol spray.

25. A composition according to Claim 24, wherein the propellant comprises fluorocarbon.

26. A composition according to Claim 25, wherein the propellant comprises tetrafluoroethane.

27. A composition according to Claim 24, wherein the propellant comprises one or more of propane, n-butane and isobutane.

28. A composition according to Claim 27, wherein the propellant comprises mixture of propane, n-butane and isobutane.

29. A composition according to Claim 24, wherein the propellant is present in the composition in a proportion in the range of 80 to 99.9% wt/wt.

30. A composition according to Claim 29, wherein the propellant is present in the composition in a proportion of substantially 98.5% wt/wt.

31. A composition according to Claim 28, wherein the propellant is present in the composition in a proportion in the range of 75 to 99% wt/wt.

32. A composition according to Claim 31, wherein the propellant is present in the composition in a proportion of substantially 95% wt/wt.

33. A composition according to Claim 32, wherein the isobutane is present in a proportion in the range of 10 to 25% wt/wt, the n-butane is present in a proportion in the range of 25 to 55% wt/wt, and the propane is present in a proportion in the range of 20 to 60% wt/wt.

34. A composition according to Claim 33, wherein the isobutane is present in a proportion of substantially 14% wt/wt, the n-butane is present in a proportion of substantially 29% wt/wt, and the propane is present in a proportion in the range of substantially 52% wt/wt.

35. A composition substantially as herein described with reference to Example I or Example II.

36. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope or or relating to the same invention as any of the prececding Claims.