CA2028990C - Fluorescent lamp with protective assembly - Google Patents
Fluorescent lamp with protective assemblyInfo
- Publication number
- CA2028990C CA2028990C CA 2028990 CA2028990A CA2028990C CA 2028990 C CA2028990 C CA 2028990C CA 2028990 CA2028990 CA 2028990 CA 2028990 A CA2028990 A CA 2028990A CA 2028990 C CA2028990 C CA 2028990C
- Authority
- CA
- Canada
- Prior art keywords
- tube
- protective
- collar
- glass tube
- protective tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Vessels And Coating Films For Discharge Lamps (AREA)
- Laminated Bodies (AREA)
Abstract
A fluorescent lamp comprises a protective cover assembly comprising a protective tube preformed of a semi-rigid non-frangible transparent polymeric material and received over the glass tube with a clearance between the outer surface of the glass tube and the inner surface of the protective tube and extending lengthwise substantially coextensively with the glass tube and a collar preformed of a heat-shrinkable polymeric material received in overlapping relation over a portion of the protective sleeve at each end thereof and over the flange portion of the adjacent cap, the collar being heat-shrunk into sealed relation with the protective tube and the cap flange portion.
Description
~ ~c~
FLUORESCENT LAMP WITH PROTECTIVE ASSEMBLY
SPECIFICATION
. .
BACKGRoUND OF THE INVENTION
When a fluorescent lamp breaks, fragments of the glass tube and powders from the phosphor coating inside the tube are scattered. In many situations in which fluore cent lighting is used, the food processing industry being a parti~ularly prevalent example, tha glass fragments and phosphor powders present an environmental hazard. ~o prevent glass fragments and powdars from scattering, it is well-kno~n to pro~ide a protective plastic coating directly onto the external surface of the glass tube. While such a coating inhibits sca~tering of materials from a broken lamp, the pr28ently availabl2 I'sa~ety" type fluorescent lamp~
becom~ di~colored, especially near ~he ends where the light o~u~ ~rom th~ lamp is highly ultraviol~t, within a few day~ of bRing placed in service. The discoloration r~nc~
thQ light ou~uL of the lamp and i~ aesth2tically " ~ , , --displeasing. Also, ~he coating over the glass env~l~ps doas not always retain the metal cap~ intac~ with th~ ~r~gmen~ed glass tube, and glass fragmen~s and powder can be rele~sed if a cap separates.
SUMMARY OF THE INVENTION
An object of the present inven~ion is to provide a fluorescent lamp having very effective protection against scattering of glass fragments from the tuhe and powders ~rom the coatinq in the event that the lamp breaks. A further object is to provide such protection in a way that does not reduce the light output during the useful life of the lamp due to discoloration or clouding of the protective element.
Still another object is to provide a "safety" fluorescent lamp that i5 easy and inexpensive to produce. The foregoing and other objects are attained, according to the present invention, by a protective cover assembly comprising a semi-ri~id non-frangible pro~ective ~ube prefo~med of a transparsnt polymeric material and received over the glas~
tube o~ the lamp with a clearance between the out~r surface of the glass tube and the inner surface of the protective tube and extending lengthwise substantially coextensively with the glass tube and a collar preformed o~ a heat-shrinkable polymeric material received in overlapping relation over a portion of th~ protective sleeve at each end thereo~ and over th~ flange portion o~ the adjacent cap, the collar being heat-shrunk into s~aled relatlon with the protectlve tube and the cap ~lange portion. In a praferred o~ltmen~ of th~ invention a layer of an adhesive is , ~8~
interpo~ed between each collar and the corresponding end o~
~ the protective tube and the corresponding cap ~lange portion.
For a ~etter underst~n~ing of the invention reference may be made to the following description of an exemplary embodiment, taken in conjunction with the accompanying drawing.
DESCRIPTION OF THE DRAWI~G
The drawing is a partial side cross-sectional view of an embodiment of a protective assem~ly as installed on a conventional fluorescent ~amp.
Reference numeral 10 designates a conventional, co~mercially available ~luorescent lamp o~ the type havin~
an elonga~ed glass tube ~2 that necks down slightly at each and is closed at each end by a cup-like end cap 14 having a peripheral flange portion 16~ The protsctive asse~bly consi~t~ of a protective tube 18 preformed from a semi-rigid non-Prangible transparen~ polymeric materlal and received over tha glass tube with a clearance l'c" between the outer sur~ace of the gla~s tube and the inner surface of th~
protec~ivq tube and extending lengthwise substantially co~xtensively with the glass tu~e and a collar 20 pre~or~ad from a h~at- hrinkable polymeric material received in overlappin~ relation over a por~ion o~ th~ protective sleeva at each end ~hereo~ and over ~he flange portion o~ th~
ad~ac~nt cap. Th~ collar is heat-shru~k into s~aled . -3-.
'~28~
relation with the protective ~ube and th~ cap ~la~ge portion. A layer 22 of an adhesive is interposed betwe~n each collar and the corresponding end of the protectiv~ tub~
and the corresponding cap ~lange portion. The adhe~ive layer i~ not present between the glass tubs of th~ lamp and the collars.
In a specific example of the invention, as applied to a 1.50 in. fluorescent tube, the protective tube 18 i a piece cut to a length such as to extend over the full diam-eter portion of the lamp tube (bl~t no~ over the necked-down part~ at either end) from an extrusion of a polycarbonate res~n that is highly stabilized against ultra-violet radia-. tion. The tubing is available comm~rcially from Thermo-plastlc Processors, Incorporated, of Sterling, New Jersey, 1~ -as Product No. 58 W, which is manufactured from a resin is supplied by Mobay, Incorporated (Resin No. 3207-1112~50).
The protective tube has a wall-thickness o~ 0.015 in., an inside diameter of 1~ 517 in. and an outside diameter o~
1.547 in. Therefore, on the diameter, the clearance between the ou~ide o~ ~he glass tube and the insi~e of th~ protec-tivs tub~ is 0.01? in. The clearance is desirable in that is provide~ a thermal insulating barrier between to glass tube and the protective tube that keep~ the protectiv~ tube ~ro~ being highly he~ted. Also, it facilitates a.~se hling the protective tube onto a finished lamp. The collars 20 are pi~ces cut to a length of 1.5 in. from a tubing product available commercially fro~ E. H. Canis & Son, Inc., of MQtuchen, NJ, un~er the trademark "Astramelt." About 1.0 in. o~ the collar overlap~ the protective tub~. Tha adhe~ i 3M No. 4693 and provides additional mech~cal 2 ~
retentlo~ over and above that provided by shrinking the - collar and also provides a moisture barrier and herme~ic seal between the lamp and the protective assembly.
If the protected lamp breaks, the protectivs A~, hly retains the caps and prevents the dispersal of glass fragments and phosphor powders. The protective assembly does not appear to reduce the light transmission, because the protective tube is entirely transparent. The protective tube of an experimental assembly according to the above exa~ple has shown no tendency to discolor after a year in service.
,.. .... . .. . .. ... . .. . . .
FLUORESCENT LAMP WITH PROTECTIVE ASSEMBLY
SPECIFICATION
. .
BACKGRoUND OF THE INVENTION
When a fluorescent lamp breaks, fragments of the glass tube and powders from the phosphor coating inside the tube are scattered. In many situations in which fluore cent lighting is used, the food processing industry being a parti~ularly prevalent example, tha glass fragments and phosphor powders present an environmental hazard. ~o prevent glass fragments and powdars from scattering, it is well-kno~n to pro~ide a protective plastic coating directly onto the external surface of the glass tube. While such a coating inhibits sca~tering of materials from a broken lamp, the pr28ently availabl2 I'sa~ety" type fluorescent lamp~
becom~ di~colored, especially near ~he ends where the light o~u~ ~rom th~ lamp is highly ultraviol~t, within a few day~ of bRing placed in service. The discoloration r~nc~
thQ light ou~uL of the lamp and i~ aesth2tically " ~ , , --displeasing. Also, ~he coating over the glass env~l~ps doas not always retain the metal cap~ intac~ with th~ ~r~gmen~ed glass tube, and glass fragmen~s and powder can be rele~sed if a cap separates.
SUMMARY OF THE INVENTION
An object of the present inven~ion is to provide a fluorescent lamp having very effective protection against scattering of glass fragments from the tuhe and powders ~rom the coatinq in the event that the lamp breaks. A further object is to provide such protection in a way that does not reduce the light output during the useful life of the lamp due to discoloration or clouding of the protective element.
Still another object is to provide a "safety" fluorescent lamp that i5 easy and inexpensive to produce. The foregoing and other objects are attained, according to the present invention, by a protective cover assembly comprising a semi-ri~id non-frangible pro~ective ~ube prefo~med of a transparsnt polymeric material and received over the glas~
tube o~ the lamp with a clearance between the out~r surface of the glass tube and the inner surface of the protective tube and extending lengthwise substantially coextensively with the glass tube and a collar preformed o~ a heat-shrinkable polymeric material received in overlapping relation over a portion of th~ protective sleeve at each end thereo~ and over th~ flange portion o~ the adjacent cap, the collar being heat-shrunk into s~aled relatlon with the protectlve tube and the cap ~lange portion. In a praferred o~ltmen~ of th~ invention a layer of an adhesive is , ~8~
interpo~ed between each collar and the corresponding end o~
~ the protective tube and the corresponding cap ~lange portion.
For a ~etter underst~n~ing of the invention reference may be made to the following description of an exemplary embodiment, taken in conjunction with the accompanying drawing.
DESCRIPTION OF THE DRAWI~G
The drawing is a partial side cross-sectional view of an embodiment of a protective assem~ly as installed on a conventional fluorescent ~amp.
Reference numeral 10 designates a conventional, co~mercially available ~luorescent lamp o~ the type havin~
an elonga~ed glass tube ~2 that necks down slightly at each and is closed at each end by a cup-like end cap 14 having a peripheral flange portion 16~ The protsctive asse~bly consi~t~ of a protective tube 18 preformed from a semi-rigid non-Prangible transparen~ polymeric materlal and received over tha glass tube with a clearance l'c" between the outer sur~ace of the gla~s tube and the inner surface of th~
protec~ivq tube and extending lengthwise substantially co~xtensively with the glass tu~e and a collar 20 pre~or~ad from a h~at- hrinkable polymeric material received in overlappin~ relation over a por~ion o~ th~ protective sleeva at each end ~hereo~ and over ~he flange portion o~ th~
ad~ac~nt cap. Th~ collar is heat-shru~k into s~aled . -3-.
'~28~
relation with the protective ~ube and th~ cap ~la~ge portion. A layer 22 of an adhesive is interposed betwe~n each collar and the corresponding end of the protectiv~ tub~
and the corresponding cap ~lange portion. The adhe~ive layer i~ not present between the glass tubs of th~ lamp and the collars.
In a specific example of the invention, as applied to a 1.50 in. fluorescent tube, the protective tube 18 i a piece cut to a length such as to extend over the full diam-eter portion of the lamp tube (bl~t no~ over the necked-down part~ at either end) from an extrusion of a polycarbonate res~n that is highly stabilized against ultra-violet radia-. tion. The tubing is available comm~rcially from Thermo-plastlc Processors, Incorporated, of Sterling, New Jersey, 1~ -as Product No. 58 W, which is manufactured from a resin is supplied by Mobay, Incorporated (Resin No. 3207-1112~50).
The protective tube has a wall-thickness o~ 0.015 in., an inside diameter of 1~ 517 in. and an outside diameter o~
1.547 in. Therefore, on the diameter, the clearance between the ou~ide o~ ~he glass tube and the insi~e of th~ protec-tivs tub~ is 0.01? in. The clearance is desirable in that is provide~ a thermal insulating barrier between to glass tube and the protective tube that keep~ the protectiv~ tube ~ro~ being highly he~ted. Also, it facilitates a.~se hling the protective tube onto a finished lamp. The collars 20 are pi~ces cut to a length of 1.5 in. from a tubing product available commercially fro~ E. H. Canis & Son, Inc., of MQtuchen, NJ, un~er the trademark "Astramelt." About 1.0 in. o~ the collar overlap~ the protective tub~. Tha adhe~ i 3M No. 4693 and provides additional mech~cal 2 ~
retentlo~ over and above that provided by shrinking the - collar and also provides a moisture barrier and herme~ic seal between the lamp and the protective assembly.
If the protected lamp breaks, the protectivs A~, hly retains the caps and prevents the dispersal of glass fragments and phosphor powders. The protective assembly does not appear to reduce the light transmission, because the protective tube is entirely transparent. The protective tube of an experimental assembly according to the above exa~ple has shown no tendency to discolor after a year in service.
,.. .... . .. . .. ... . .. . . .
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a fluorescent lamp of the type having an elongated glass tube and metal caps at each end, the glass tube having an outer surface and each cap having a peripheral flange portion, the improvement of a protective cover assembly comprising a protective tube preformed of a semi-rigid non-frangible transparent polymeric material that is highly stabilized against ultra-violet radiation, the protective tube having an inner surface and being received over the glass tube with a clearance between the outer surface of the glass tube and the inner surface of the protective tube and extending lengthwise substantially coextensively with the glass tube, a collar preformed of a heat-shrinkable polymeric material received in overlapping relation over a portion of the protective tube at each end thereof and over the flange portion of the adjacent metal cap of the lamp, the collar being heat-shrunk into sealed relation with the protective tube and the cap flange portion, a layer of an adhesive interposed between each collar and the corresponding end of the protective tube and a layer of an adhesive interposed between the collar and the corresponding cap flange portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US55591290A | 1990-07-19 | 1990-07-19 | |
| US07/555,912 | 1990-07-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2028990A1 CA2028990A1 (en) | 1992-01-20 |
| CA2028990C true CA2028990C (en) | 1998-11-17 |
Family
ID=24219098
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2028990 Expired - Lifetime CA2028990C (en) | 1990-07-19 | 1990-10-30 | Fluorescent lamp with protective assembly |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2028990C (en) |
-
1990
- 1990-10-30 CA CA 2028990 patent/CA2028990C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2028990A1 (en) | 1992-01-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |