Amalgam balls having an alloy coating

Patent metadata

Field	Value
Publication number	US-2016133453-A1
Application number	US-201615000752-A
Country	US
Kind code	A1
Filing date	Jan 19, 2016
Priority date	Mar 9, 2011
Publication date	May 12, 2016
Grant date	—

Abstract

Energy-saving lamps contain a gas filling of mercury vapour and argon in a gas discharge bulb. Amalgam balls are used for filling the gas discharge bulb with mercury. Novel coated balls whose operating life in the case of automatic metered introduction is increased by coating of the balls with an alloy powder and conglutination of the amalgam balls during storage and processing is prevented are proposed,

First claim

1 . An amalgam ball which is coated with an alloy powder, wherein
the alloy powder has a composition of silver (Ag) from 3% by weight to 80% by weight, copper (Cu) from 0,5% by weight to 43% by weight, tin (Sn) from 0% by weight to 96.5% by weight, zinc (Zn) from 0% by weight to 5% by weight, indium (In) from 0% by weight to 10% by weight and gold, palladium and platinum (Au/Pd/Pt), individually or in combination with one another, from 0% by weight to 5% by weight, where the amounts of the metals add up to a total of 100% by weight.

2 . An amalgam ball as claimed in claim 1 , wherein
the powder particles have a particle diameter of less than 100 μm.

3 . An amalgam ball as claimed in claim 1 , wherein
the alloy powder contains more than 3% by weight of silver or copper when the tin content is greater than 90% by weight.

4 . An amalgam ball as claimed in claim 1 ,
wherein the amalgam ball is coated with an amount of from 1 to 10% by weight, based on the weight of the ball, of the alloy powder.

5 . An amalgam ball, as claimed in claim 1 ,
wherein: the amalgam ball is additionally coated with an amount of from 0.001 to 1% by weight of a powder of a metal oxide.

6 . An amalgam ball as claimed in claim 1 ,
wherein the amalgam is an amalgam of the metals tin (Sn), zinc (Zn), bismuth (Bi), indium (In) and alloys of these with one another.

7 . An amalgam ball as claimed in claim 1 ,
wherein the ball has a diameter in the range from 50 to 3000 μm.

8 . A process for producing the amalgam balls as claimed in claim 1 ,
wherein the amalgam is completely melted and the melt is introduced dropwise into a cooling medium having a temperature below the solidification temperature of the amalgam and the amalgam balls formed are subsequently separated off from the cooling medium.

9 . The process as claimed in claim 8 ,
wherein the amalgam balls are degreased after having been separated from the cooling medium and are sprinkled at room temperature with the alloy powder while agitating continually until the balls no longer stick together.

10 . The process as claimed in claim 8 , wherein the amalgam balls are subjected to a heat treatment after sprinkling with alloy powder.

11 . The process as claimed in claim 8 , wherein at least one of the steps selected from the group consisting of sprinkling of the amalgam balls with alloy powder, coating with a metal oxide or heat treatment of the amalgam balls is repeated.

12 . A method of controlling the reabsorption of mercury in amalgam balls for low-pressure gas discharge lamps by coating the amalgam balls with an alloy powder which has a composition as claimed in claim 1 .

13 . A process for producing a low-pressure gas discharge lamp comprising inclusion of at least one of the amalgam balls as claimed in claim 1 in a lamp body.

14 . A low-pressure gas discharge lamp containing at least one amalgam ball as claimed in claim 1 which is enclosed in the low-pressure gas discharge lamp.

15 . A process for producing low-pressure gas discharge lamps, which comprises at least the following steps:
provision of amalgam balls by a process as claimed in claim 12 ; provision of a glass body for the low-pressure gas discharge lamp; introduction of one or more amalgam balls into the glass body; closing of the glass body.

Assignees

• Umicore Ag & Co Kg

Inventors

• Hutin Olivier
• Ringelstein Hans Martin

Classifications

• H01J9/40

  Closing vessels · CPC title

• C22C13/00

  Alloys based on tin · CPC title

• H01J61/20

  mercury vapour · CPC title

• C22C7/00

  Alloys based on mercury · CPC title

• H01J61/26 Primary

  Means for absorbing or adsorbing gas, e.g. by gettering; Means for preventing blackening of the envelope · CPC title