US3742278A

US3742278A - Low pressure mercury vapor gas discharge lamp with amalgam

Info

Publication number: US3742278A
Application number: US00136482A
Authority: US
Inventors: V Tyabirdin; G Snitka; N Vasyagin; J Shindelman; G Akulova
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-05-25
Filing date: 1971-04-22
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: SU308689A1; DE2118767C3; DE2118767B2; GB1304335A; DE2118767A1

Abstract

Low-pressure mercury-vapor gas-discharge lamps, particularly fluorescent ones, of high intensity and high specific power, containing an amalgam of the formulation: MERCURY15 - 20 AT. PER CENT CADMIUM53 - 38 AT. PER CENTTIN20 25 AT. PER CENT BISMUTH12 - 17 AT. PER CENT

Description

United States Patent [1 1 Shindelman et al. I

[ June 26, 1973 LOW-PRESSURE MERCURY-VAPOR GAS-DISCHARGE LAMP WITH AMALGAM Inventors: Jury losiiovich Shindelmau, ulitsa Kalinina, 3, kv. 57; Galina Iosifovna Akulova, ulitsa Tsiolkovskogo, 37, kv. 63; Galina Grigorievna Snitka, ulitsa Birjuzova, 31, kv. 2; Nikolai lvanovich Vasyagin, ulitsa Zygina, 42, kv. 54; Vladimir Vasilievich Tyabirdin, ulitsa Zygina, 42, kv. 45, all of Poltava, U.S.S.R.

Filed: Apr. 22, 1971 Appl. No.: 136,482

Foreign Application Priority Data May 25, 1970 U.S.S.R 1429909 US. Cl. 313/109, 313/174 Int. Cl. Hlj 61/24 Field of Search, 313/174, 109, 179

[56] References Cited UNITED STATES PATENTS 3,007,071 /1961 Lompe et a1 313/109 X 3,152,278 10/1964 Dziergwa et a1. 313/109 X Primary Examiner-Pa1mer C. Demeo Att0rneyHo1man & Stern [57] ABSTRACT Low-pressure mercury-vapor gas-discharge lamps, particularly fluorescent ones, of high intensity and high specific power, containing an amalgam of the formulation:

mercury at, per cent cadmium 53 38 at. per cent tin 20 at. per cent bismuth 12 17 at. per cent 2 Claims, 2 Drawing Figures LOW-PRESSURE MERCURY-VAPOR GAS-DISCHARGE LAMP WITH AMALGAM The present invention relates to electric gasdischarge lamps with an amalgam, notably of highintensity, 80-200 W fluorescent lamps of high specific power, and also to fluorescent lamps of ordinary specific power, used under adverse temperature conditions, such as in unventilated enclosed lighting fixtures.

In the prior art, there are low-pressure mercuryvapor gas-discharge lamps containing various bicomponent amalgams (cadmium-mercury, indiummercury, thallium-mercury, etc.), tri-component amalgams (cadmium-tin-mercury, indium-zinc-mercury, etc.), and tetra-component amalgams (indium cadmium-tin-mercury, lead-bismuth-cadmium-mercury).

A major disadvantage of gas-discharge lamps using the above-listed prior-art amalgams consists in that they have a high luminous yield only in a very narrow range of ambient temperature (40] to 55] C), while, as numerous investigations have shown, the walls of highintensity, high-specific power fluorescent lamps used in enclosed lighting fixtures may have a temperature of 60] to 70} C.

With fluorescent lamps of ordinary specific power, the temperature in unventilated enclosed lighting fixtures may likewise range from 45] to 70] C, depending on the number of lamps enclosed.

It is an object of the present invention to avoid these disadvantages and to provide fluorescent lamps witha luminous flux stable over a wide range of ambient temperature (from 40] to 80] C).

Another object of the invention is to provide a nontoxic solid amalgam by the proper choice of its formulation, which can be used in both high-intensity, highpower and ordinary-power fluorescent lamps employed in unventilated enclosed lighting fixtures and will have a high luminous output over the temperature range indicated.

With these and other objects in view, the present invention resides in that in order to ensure a stable luminous flux over a wide range of ambient temperature (from 40] to 80] C), use is made of an amalgam of the formulation: mercury, at. percent; cadmium, 53 38 at. percent; tin, 20 at. percent; and bismuth, l2 17 at. percent.

The amalgam disclosed herein has a melting point of 190] to 210] C; it will remain solid when used in a lamp and sufficiently plastic in the course of manufacture, so that it can be made into any shape (bars, balls, and the like).

The invention will be more fully understood from the following description of a preferred embodiment when read in connection with the accompanying drawings wherein:

FIG. 1 is a plot relating the luminous flux of a 80 W fluorescent lamp using a specific amalgam formulation,

to ambient temperature; FIG. 2 is a plot relating the luminous flux of a 125 W fluorescent lamp using various amalgam formulations, to ambient temperature.

Referring to FIG. 1, an amalgam of the formulation: mercury, 15 at. percent; tin, 25 at. percent; cadmium, 48 at. percent; and bismuth, 12 at. percent, shifts the peak of the luminous flux into the region of high temperatures. At a temperature of 80] C, the luminous flux is only 8 percent below the peak.

Curves A, B, and C in FIG. 2 illustrate the performance ofa 125 W fluorescent lamp having an envelope 150 cm long and using various amalgam formulations. These amalgam formulations are summarized in Table l.

TABLE I Ingredient, Curve atomic percent A B C Mercury (Hg) l5 17 20 Cadmium (Cd) 48 46 38 Tin (Sn) 25 22 25 Bismuth (Bi) 12 15 17 Total 100 at. percent 100 at. percent 100 at. percent This lamp has a luminous peak in the temperature range from 65] to C. It can be operated over a temperature range of 40] to C., and its luminous flux at the limiting temperature falls off by not more than 7 percent from the peak.

From a comparison of curves B and D (FIG. 2), it is seen that a mercury lamp (curve D) is markedly inferior to an amalgam lamp (curve B) in terms of luminous flux. It has been calculated that the luminous flux of a W fluorescent lamp using an amalgam exceeds that of a 125 W fluorescent lamp using straight mercury by 18 percent at 50] C, by 20 percent at 60] C, and by 32 percent at 70] C.

These differences are traceable to the metals used in the amalgam and their percentages.

The yield of mercury vapor from the amalgam is decided by intermetallic mercury-cadmium and mercurybismuth compounds. In contrast to classical chemical bonds, ionic and covalent, these compounds feature a specific metallic bond which invalidates the valence theory.

In the amalgams disclosed herein the formation of intermetallic compounds depends on the percentage of mercury in the amalgam. It may be thought that the amalgam corresponding to curve B contains no free mercury.

The thermal effect on the amalgam in which the tin acts as a stabilizer of mercury yield is such that the pressure of mercury vapor is optimum (3 10.3 mm Hg) for the desired resonance radiation to be emitted in a 125 W fluorescent lamp.

The high efficiency of gas-discharge lamps using an amalgam of the formulation corresponding to curve B is augmented by the fact that they do not call for ventilated lighting fixtures of complicated design.

Since the pressure of mercury pressure over this amalgam at 201C is about 10..5mm Hg, any contamination of the surrounding premises is completely eliminated.

The amalgam is prepared from inexpensive and abundant materials and compares favorably with any of prior-art amalgams for gas-discharge lamps in terms of cost, performance and low toxicity.

What is claimed is: 1 l. A low-pressure mercury-vapor gas-discharge lamp, of high intensity and high specific power, containing an amalgam of the formulation:

mercury cadmium tin bismuth l 20 at. percent 53 38 at. percent 20 25 at. percent 12 17 at. percent.

Claims

2. A mercury vapor gas-discharge lamp as claimed in claim 1 which includes means rendering the lamp fluorescent.