CA1239978A - Low-pressure mercury vapour lamp containing amalgam - Google Patents
Low-pressure mercury vapour lamp containing amalgamInfo
- Publication number
- CA1239978A CA1239978A CA000477845A CA477845A CA1239978A CA 1239978 A CA1239978 A CA 1239978A CA 000477845 A CA000477845 A CA 000477845A CA 477845 A CA477845 A CA 477845A CA 1239978 A CA1239978 A CA 1239978A
- Authority
- CA
- Canada
- Prior art keywords
- lamp
- discharge vessel
- mercury vapour
- low
- discharge
- 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
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/24—Means for obtaining or maintaining the desired pressure within the vessel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/30—Vessels; Containers
- H01J61/32—Special longitudinal shape, e.g. for advertising purposes
- H01J61/325—U-shaped lamps
Landscapes
- Vessels And Coating Films For Discharge Lamps (AREA)
- Discharge Lamp (AREA)
Abstract
ABSTRACT:
A low-pressure mercury vapour discharge lamp comprises a discharge vessel which is sealed in a vacuum-tight manner and has at least two parallel tube parts (1,2) arranged beside each other and connected to each other at or near their one ends (3). During opera-tion a cool area (4,5) is present in the discharge vessel near the connection (3). The discharge vessel contains an amalgam (13) for controlling the mercury vapour pressure in the discharge vessel during operation of the lamp in order to prevent condensation of mercury occurring at the cool area.
A low-pressure mercury vapour discharge lamp comprises a discharge vessel which is sealed in a vacuum-tight manner and has at least two parallel tube parts (1,2) arranged beside each other and connected to each other at or near their one ends (3). During opera-tion a cool area (4,5) is present in the discharge vessel near the connection (3). The discharge vessel contains an amalgam (13) for controlling the mercury vapour pressure in the discharge vessel during operation of the lamp in order to prevent condensation of mercury occurring at the cool area.
Description
~3~
P~ 10.934 l 04-03-1985 The invention relates to a ]ow-pressure mercury vapour dischar-ge lam? con~rising a discharge vessel which is sealed in a vacuum-tight n~nner and has at least two parallel tuke parts arranged beside each other and connected to each other at or near their one ends, there being present in the discharge vessel duriny operation of the lamp a discharge path between electrodes provided at the other ends of the tube parts, discharge path which is curved at at least one area, the discharge ves-sel being shaped near the connection between the tube parts in a rnanner such that during operation of the lamp in situ a part of the inner wall of the discharge vessel has a comparatively low temperature.
Such a lamp is kncwn from British Patent Specification 2050046.
The known lamp is comparatively compact and serves as an alter-native to incandescent lam?s for general illumination ?urposes.
In the case of an increase of the electrical energy supplied to such a lamp or if the lamp is operated in a space in which the tempera-ture is higher than the normal room te~mperature (for example in a closed luminaire of small dimensions~, the light output nevertheless remains comparatively high. The mercury vapour pressure in the discharge vessel is in fact stabilized at an optim~ ~ roximately 10 2 torr) due to the 20 presence of the cool area in the discharge vessel near the end of a tube part.
However, it has been found that condensation of mercury is lia-ble to occur at the cool area in the discharge vessel under nornnal ope-rating conditions. This is especially disadvantageolls ifthe lamp is ar-25 ranged in a vertical operating position, in which the electrodes are si-tuated at the lower end of the lamp. They are then located substantially perpendicularly below the com?aratively cool wall portior~ There is then a risk that the mercury drips d~nwards along the wall of the discharge vessel, as a result of which a luminescent layer present on the inner 30 wall of the discharge vessel is at-tacked. rrhis is no-t only detrimental to the light output, but rr~oreover the ap?earance of the lamp is spoilt.
F~1rthermore there is also a risk that the liquid mercury falls dcwnwards in the form of drops and impinges on the filament spiral of an electrode.
~1 P~ 10.994 2 04-03~1985 This adversely affects the operation of the lamp. Moreover, with the oc~
curence of this phenomenon, fluctuations in the light output are obt~ined and the light intensity distribution over the discharge vessel is inho-mogeneous The invention has for its object to provide a lamp having a high light output, in which, however, the aforementioned disadvantageous phe-nomena are avoided.
According to the invention, a low-pressure mercury vapour dis-charge lamp of the kind mentioned in the opening paragraph is for this purpose characterized in that the discharge vessel contains an amalgam for controlling the rnercury vapour pressure in the discharge vessel du-ring operation of the lamp.
In the lamp according to the invention, the aforementioned unde-sirable phenomena do not occur. The mercury vapour pressure is controlled in the discharge vessel under normal operating conditions by the amalgam, as a result of which no condensation of mercury takes place at the cool area in the discharge vessel. The mercury vapour pressure during operation of the lamp is rnoreover stabilized at a value of approxirnatRly 10 torr over a wide temperature range~ The light output of the lamp then remains as high as possible even if the lamp is operated in a comparatively warm area, such as in a luminaire.
The amalgam is preferably situated at an area behind one of the - electrodes. A suitable area is, for example, the hase of the so-called mount. Such a mount is provided not only with an electrode, but, for example, also with wires for this electrode as well as with an exhaust tuhR located behind the electrode which is used for pumping the discharge vessel In a preferred er~odiment of the lamp according to the invention, the arnalgam is present in the exhaus-t tU~R. It has bRen found that such an area is favourable for a satisfactory vapour pressure stahilization.
The amalgam present in the discharge vessel of the larnp according to the invention consists, for example, of an alloy of indium and mercu-ry or of an alloy of indium, bismuth and mercury (see, for exarnple, British Patent SpRcification 1503636). Favourable results were obtained with an amalgam consis-ting of bismuth, lead, tin and mercury ~see, for example, British Patent Specification 1572657).
The discharge vessel of the lamp according to the invention may have differen-t shapes. The discharge vessel may comprise, for example, ~,~3~
PHN 10.994 3 04-03-1985 two tuke parts which are connected to each o-ther by a transverse connec-tion, as descril~ed in the aforementioned British Paten-t Specification 2050046. However, it may alternatively comprise four such interconnected tube parts. Favourable results were also obtained with a lamp having a 5 discharge vessel of the kind described in German Offenlegungsschrift 3112878. In this k~mp, a cool wall portion is ob-tained by shaping a dis-charge tuke which is in the form of a U at the area of the curved part in a manner such that a wall portion is obtained whose cross-section ex-tends substan-tially at right angles to the direction of the axis.
An em~cdiment of the invention will now be described more fully with reference to -the accompanying drawing. In the drawing, a l~pressure mercury vapour discharge lamp according to the invention is shown, partly in elevation and par-tly in sectional view.
The lamp comprises a discharge vessel which is sealed in a va-15 cuum-tight manner (filled with m~ercury and a rare gas, such as argon) com-prising two parallel tuke parts 1 and 2, which are arranged keside each other and are connected to each other through a transverse connection 3.
The ilmer wall of the tube parts and the transverse connection is coated with a lumincescent layer. The transverse connection is provided, for 20 example, by means of a method as described in GB-PS 2048562. This trans-verse connection is located at a certain distance from the one ends 4 and 5 of the tube parts 1 and 2, respectively. These ends are in the form of end faces arranged at right angles to the longitudinal axes of the tuke parts. The electrodes 6 and 7 are arranged beside each other, each at the 25 other end of a respective tube part. ~uring operation of -the lamp, a U-shaped discharge path is present in the tube parts 1 and 2 between these electrodes.
A lamp cap 8 is secured at the ends of the tube parts ~1,2), at which the electrodes are located, and this cap preferably consists of syn-30 thetic ma-terial. The lamp cap comprises a projec-ting wall portion 9, in which a starter is provided. Current connection pins 10 and 11 are arran-ged on either side of the projecting wall portion.
During operation of -the lamp, portions of the inner wall of the discharge vessel located near the one ends of the tube parts (especia]ly 35 the wall portions ~1 and 5) are cor~?aratively cool. Without additional steps being taken, condensation of mercury can occur at these areas, which has the aforementioned disadvantageous consequences, especially if the lamp is arranged in vertical position.
~3~
PHN 10.994 4 04-03-1985 In order to counteract these phenomena, an amalgam 13 for con-trolling the vapour pressure in the discharge vessel during operation of the lamp is present in the exhaust tube 12 behind the electrode 6 forming part of the mount associated with the electrode 6, the end of the exhaust tube 12 remote from the electrode 6 being sealed. Condensation of mercury at the aforementioned ends is then avoided. The alloy forming with mercu~
ry an amalgam preferably consists of the elements lead, bismuth and tin.
In a practical embcdiment of the aforementioned lamp, the length of the tube parts is approximately 13 cm and -the inner diameter is appro-ximately 10 mm. The luminescent layer on the inner wall is a mixture of two phosphors, i.e. green luminescing terbium-activated cerium magnesium aluminate and red luminescing yttrium oxide activated by trivalent euro-pium. 180 mg of an alloy with a ration in atoms of lead,bismuth and tin equal to 16 : 36.5 : 47.5 is present in the exhaust tube. Furthermore, lS approximately 6 mg of mercury is present. With a rare gas filling of ar-gon (3 torr), the light output was approximately 600 lumen with a pcwer supplied to the lamp of approximately 9 W.
P~ 10.934 l 04-03-1985 The invention relates to a ]ow-pressure mercury vapour dischar-ge lam? con~rising a discharge vessel which is sealed in a vacuum-tight n~nner and has at least two parallel tuke parts arranged beside each other and connected to each other at or near their one ends, there being present in the discharge vessel duriny operation of the lamp a discharge path between electrodes provided at the other ends of the tube parts, discharge path which is curved at at least one area, the discharge ves-sel being shaped near the connection between the tube parts in a rnanner such that during operation of the lamp in situ a part of the inner wall of the discharge vessel has a comparatively low temperature.
Such a lamp is kncwn from British Patent Specification 2050046.
The known lamp is comparatively compact and serves as an alter-native to incandescent lam?s for general illumination ?urposes.
In the case of an increase of the electrical energy supplied to such a lamp or if the lamp is operated in a space in which the tempera-ture is higher than the normal room te~mperature (for example in a closed luminaire of small dimensions~, the light output nevertheless remains comparatively high. The mercury vapour pressure in the discharge vessel is in fact stabilized at an optim~ ~ roximately 10 2 torr) due to the 20 presence of the cool area in the discharge vessel near the end of a tube part.
However, it has been found that condensation of mercury is lia-ble to occur at the cool area in the discharge vessel under nornnal ope-rating conditions. This is especially disadvantageolls ifthe lamp is ar-25 ranged in a vertical operating position, in which the electrodes are si-tuated at the lower end of the lamp. They are then located substantially perpendicularly below the com?aratively cool wall portior~ There is then a risk that the mercury drips d~nwards along the wall of the discharge vessel, as a result of which a luminescent layer present on the inner 30 wall of the discharge vessel is at-tacked. rrhis is no-t only detrimental to the light output, but rr~oreover the ap?earance of the lamp is spoilt.
F~1rthermore there is also a risk that the liquid mercury falls dcwnwards in the form of drops and impinges on the filament spiral of an electrode.
~1 P~ 10.994 2 04-03~1985 This adversely affects the operation of the lamp. Moreover, with the oc~
curence of this phenomenon, fluctuations in the light output are obt~ined and the light intensity distribution over the discharge vessel is inho-mogeneous The invention has for its object to provide a lamp having a high light output, in which, however, the aforementioned disadvantageous phe-nomena are avoided.
According to the invention, a low-pressure mercury vapour dis-charge lamp of the kind mentioned in the opening paragraph is for this purpose characterized in that the discharge vessel contains an amalgam for controlling the rnercury vapour pressure in the discharge vessel du-ring operation of the lamp.
In the lamp according to the invention, the aforementioned unde-sirable phenomena do not occur. The mercury vapour pressure is controlled in the discharge vessel under normal operating conditions by the amalgam, as a result of which no condensation of mercury takes place at the cool area in the discharge vessel. The mercury vapour pressure during operation of the lamp is rnoreover stabilized at a value of approxirnatRly 10 torr over a wide temperature range~ The light output of the lamp then remains as high as possible even if the lamp is operated in a comparatively warm area, such as in a luminaire.
The amalgam is preferably situated at an area behind one of the - electrodes. A suitable area is, for example, the hase of the so-called mount. Such a mount is provided not only with an electrode, but, for example, also with wires for this electrode as well as with an exhaust tuhR located behind the electrode which is used for pumping the discharge vessel In a preferred er~odiment of the lamp according to the invention, the arnalgam is present in the exhaus-t tU~R. It has bRen found that such an area is favourable for a satisfactory vapour pressure stahilization.
The amalgam present in the discharge vessel of the larnp according to the invention consists, for example, of an alloy of indium and mercu-ry or of an alloy of indium, bismuth and mercury (see, for exarnple, British Patent SpRcification 1503636). Favourable results were obtained with an amalgam consis-ting of bismuth, lead, tin and mercury ~see, for example, British Patent Specification 1572657).
The discharge vessel of the lamp according to the invention may have differen-t shapes. The discharge vessel may comprise, for example, ~,~3~
PHN 10.994 3 04-03-1985 two tuke parts which are connected to each o-ther by a transverse connec-tion, as descril~ed in the aforementioned British Paten-t Specification 2050046. However, it may alternatively comprise four such interconnected tube parts. Favourable results were also obtained with a lamp having a 5 discharge vessel of the kind described in German Offenlegungsschrift 3112878. In this k~mp, a cool wall portion is ob-tained by shaping a dis-charge tuke which is in the form of a U at the area of the curved part in a manner such that a wall portion is obtained whose cross-section ex-tends substan-tially at right angles to the direction of the axis.
An em~cdiment of the invention will now be described more fully with reference to -the accompanying drawing. In the drawing, a l~pressure mercury vapour discharge lamp according to the invention is shown, partly in elevation and par-tly in sectional view.
The lamp comprises a discharge vessel which is sealed in a va-15 cuum-tight manner (filled with m~ercury and a rare gas, such as argon) com-prising two parallel tuke parts 1 and 2, which are arranged keside each other and are connected to each other through a transverse connection 3.
The ilmer wall of the tube parts and the transverse connection is coated with a lumincescent layer. The transverse connection is provided, for 20 example, by means of a method as described in GB-PS 2048562. This trans-verse connection is located at a certain distance from the one ends 4 and 5 of the tube parts 1 and 2, respectively. These ends are in the form of end faces arranged at right angles to the longitudinal axes of the tuke parts. The electrodes 6 and 7 are arranged beside each other, each at the 25 other end of a respective tube part. ~uring operation of -the lamp, a U-shaped discharge path is present in the tube parts 1 and 2 between these electrodes.
A lamp cap 8 is secured at the ends of the tube parts ~1,2), at which the electrodes are located, and this cap preferably consists of syn-30 thetic ma-terial. The lamp cap comprises a projec-ting wall portion 9, in which a starter is provided. Current connection pins 10 and 11 are arran-ged on either side of the projecting wall portion.
During operation of -the lamp, portions of the inner wall of the discharge vessel located near the one ends of the tube parts (especia]ly 35 the wall portions ~1 and 5) are cor~?aratively cool. Without additional steps being taken, condensation of mercury can occur at these areas, which has the aforementioned disadvantageous consequences, especially if the lamp is arranged in vertical position.
~3~
PHN 10.994 4 04-03-1985 In order to counteract these phenomena, an amalgam 13 for con-trolling the vapour pressure in the discharge vessel during operation of the lamp is present in the exhaust tube 12 behind the electrode 6 forming part of the mount associated with the electrode 6, the end of the exhaust tube 12 remote from the electrode 6 being sealed. Condensation of mercury at the aforementioned ends is then avoided. The alloy forming with mercu~
ry an amalgam preferably consists of the elements lead, bismuth and tin.
In a practical embcdiment of the aforementioned lamp, the length of the tube parts is approximately 13 cm and -the inner diameter is appro-ximately 10 mm. The luminescent layer on the inner wall is a mixture of two phosphors, i.e. green luminescing terbium-activated cerium magnesium aluminate and red luminescing yttrium oxide activated by trivalent euro-pium. 180 mg of an alloy with a ration in atoms of lead,bismuth and tin equal to 16 : 36.5 : 47.5 is present in the exhaust tube. Furthermore, lS approximately 6 mg of mercury is present. With a rare gas filling of ar-gon (3 torr), the light output was approximately 600 lumen with a pcwer supplied to the lamp of approximately 9 W.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A low-pressure mercury vapour discharge lamp com-prising a discharge vessel which is sealed in a vacuum-tight manner and has at least two parallel tube parts having ends in the form of end faces arranged at right angles to the longitudinal axes of the tube parts, said tube parts are arranged beside each other and connected to each other at or near said ends, there being present in the discharge vessel during operation of the lamp a discharge path between electrodes provided at the other ends of the tube part, which discharge path is curved at at least one area, the discharge vessel being shaped near the connection between the tube parts in a manner such that during opera-tion of the lamp the inner wall of said ends has a compara-tively low temperature, characterized in that the discharge vessel contains an amalgam for controlling the mercury vapour pressure in the discharge vessel during operation of the lamp.
2. A low-pressure mercury vapour discharge lamp as claimed in Claim 1, characterized in that the amalgam is present at an area behind one of the electrodes.
3. A low-pressure mercury vapour discharge lamp as claimed in Claim 2, characterized in that the amalgam is present in an exhaust tube, provided behind said electrode.
4. A low-pressure mercury vapour discharge lamp as claimed in Claim 1, 2 or 3, characterized in that the amalgam consists of lead, tin, bismuth and mercury.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8401030A NL8401030A (en) | 1984-04-02 | 1984-04-02 | LOW-PRESSURE MERCURY DISCHARGE LAMP. |
| NL8401030 | 1984-04-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1239978A true CA1239978A (en) | 1988-08-02 |
Family
ID=19843737
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000477845A Expired CA1239978A (en) | 1984-04-02 | 1985-03-28 | Low-pressure mercury vapour lamp containing amalgam |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS60225346A (en) |
| BE (1) | BE902088A (en) |
| CA (1) | CA1239978A (en) |
| DE (1) | DE3510156A1 (en) |
| FR (1) | FR2562324B1 (en) |
| GB (1) | GB2157883B (en) |
| NL (1) | NL8401030A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0746598B2 (en) * | 1986-05-29 | 1995-05-17 | 東芝ライテック株式会社 | Fluorescent lamp |
| EP0267340A1 (en) * | 1986-11-14 | 1988-05-18 | Gte Sylvania Limited | Fluorescent lamp |
| JP2776840B2 (en) * | 1988-08-26 | 1998-07-16 | 株式会社日立製作所 | Fluorescent lamp |
| JPH083997B2 (en) * | 1988-12-12 | 1996-01-17 | 東芝ライテック株式会社 | Low pressure mercury vapor discharge lamp |
| US5237240A (en) * | 1991-12-04 | 1993-08-17 | Gte Products Corporation | Mercury vapor discharge lamp containing device for heating amalgam-forming material |
| US5294867A (en) * | 1992-03-13 | 1994-03-15 | Gte Products Corporation | Low pressure mercury vapor discharge lamp containing an amalgam |
| DE19512129A1 (en) * | 1995-03-31 | 1996-10-02 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Low pressure mercury vapor discharge lamp |
| EP0845153B1 (en) * | 1996-05-17 | 2002-11-06 | Koninklijke Philips Electronics N.V. | Low-pressure mercury discharge lamp |
| JP2000173537A (en) | 1998-09-29 | 2000-06-23 | Toshiba Lighting & Technology Corp | Low pressure mercury-vapor discharge lamp and lighting system |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1589290B2 (en) * | 1967-05-11 | 1976-05-13 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München | METHOD OF APPLICATION OF AMALGAM FORMING METAL IN ELECTRICALLY AND / OR THERMALLY HIGH LOAD MERCURY LOW PRESSURE DISCHARGE LAMPS |
| US3548241A (en) * | 1968-05-06 | 1970-12-15 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Method of incorporating an amalgam or an amalgam-forming metal in a lowpressure mercury discharge lamp,and lamp produced by such method |
| GB1273663A (en) * | 1970-07-03 | 1972-05-10 | Anatoly Stepanovich Fedorenko | Fluorescent lamp apparatus |
| NL183687C (en) * | 1978-10-11 | 1988-12-16 | Philips Nv | LOW-PRESSURE MERCURY DISCHARGE LAMP. |
| NL185479C (en) * | 1979-04-03 | 1990-04-17 | Philips Nv | LOW PRESSURE GAS DISCHARGE LAMP. |
| NL185639C (en) * | 1980-10-29 | 1990-06-01 | Philips Nv | LOW-PRESSURE MERCURY DISCHARGE LAMP. |
-
1984
- 1984-04-02 NL NL8401030A patent/NL8401030A/en not_active Application Discontinuation
-
1985
- 1985-03-21 DE DE19853510156 patent/DE3510156A1/en not_active Withdrawn
- 1985-03-28 CA CA000477845A patent/CA1239978A/en not_active Expired
- 1985-03-29 FR FR8504816A patent/FR2562324B1/en not_active Expired
- 1985-03-29 GB GB08508197A patent/GB2157883B/en not_active Expired
- 1985-04-01 BE BE0/214764A patent/BE902088A/en not_active IP Right Cessation
- 1985-04-01 JP JP6671685A patent/JPS60225346A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB8508197D0 (en) | 1985-05-09 |
| FR2562324B1 (en) | 1988-10-14 |
| GB2157883A (en) | 1985-10-30 |
| NL8401030A (en) | 1985-11-01 |
| FR2562324A1 (en) | 1985-10-04 |
| BE902088A (en) | 1985-10-01 |
| DE3510156A1 (en) | 1985-10-10 |
| GB2157883B (en) | 1988-07-27 |
| JPS60225346A (en) | 1985-11-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |