Process for gaseously opalizing bulbs

• US 4,374,157 A
• Filed: 08/28/1981
• Issued: 02/15/1983
• Est. Priority Date: 09/10/1980
• Status: Expired due to Term

• Current Assignee: L'Air Liquide Societe Anonyme
• Original Assignee: L'Air Liquide SA
• Inventors: Barbier, Jean-Paul, Lerouyer, Gilbert
• Primary Examiner(s): Hoffman, James R.
• Application Number:
  US06/297,366
• Time in Patent Office: 536 Days
• Field of Search: 427/37, 427/106, 427/107, 427/164, 427/167, 427/237
• US Class Current: 427/580
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2218/152 by cvd
• CPC Class Codes: H01J 61/35 provided with coatings on the walls thereof; Selection of materials for the coatings using coloured coatings H01J61/40; using luminescent coatings H01J61/42
• CPC Class Codes: H01K 1/32 provided with coatings on the walls; Vessels or coatings thereon characterised by the material thereof
• CPC Class Codes: H01K 3/00 Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof manufacture of vessels from glass C03B

Abstract

Glass bulbs are given a deposit of silica by oxidation of silane with oxygen on the inside of the bulb. The silica deposit is formed by oxidation, with oxygen through an electric arc, of silane diluted to a slight concentration of 0.1 to 3% by volume in a gas inert in regard to silane. The process applies to opalizing, i.e. providing a light diffusing layer, incandescent and discharge bulbs of different sizes, including tubes, and globes of lighting fixtures.

Claims

1. A process of gaseously opalizing a bulb comprising forming and depositing silica on the inside of the bulb by oxidation of silane with oxygen by means of an electric arc, said silane being diluted to a concentration of 0.1 to 3% by volume in a gas inert in regard to the silane.

2. The process of gaseously opalizing a bulb according to claim 1, wherein the concentration of silane in the inert gas is between 1 and 2%.

3. The process of gaseously opalizing a bulb according to claim 1, wherein the electric arc is fed an AC voltage between 5,000 and 10,000 volts.

4. The process of gaseously opalizing a bulb according to claim 1, wherein the flow rate of dilute silane is between 100 and 500 liters/hour and the oxygen delivery is between 10 and 60 liters/hour.

5. The process of gaseously opalizing a bulb according to claim 1, wherein the opalization is effected with external cooling of the bulb during opalization.

6. The process of gaseously opalizing a bulb according to claim 1, wherein the opalization is performed with the interior of the bulb being maintained under slightly reduced pressure during opalization.

7. The process of opalizing a bulb according to any one of claims 1, 3, 4 or 6, wherein a homogeneous mixture of the two gaseous fluids--dilute silane and oxygen--is made on the inside of the bulb before passage of said gaseous mixture through the electric arc.

8. The process of opalizing a bulb according to any one of claims 1, 3, 4, or 6, wherein there is performed a central feeding of the dilute silane and a lateral feeding of oxygen with the silane delivery rate being much higher than that of the oxygen.

9. The process of opalizing a bulb according to any one of claims 1, 3, 4 or 6, wherein the two gaseous fluids--dilute silane and oxygen--are homogeneously premixed outside of the bulb with the mixture being introduced through a central supply to the interior of the bulb.

10. The process of gaseously opalizing a bulb according to claim 1, wherein the flow rate of dilute silane is between 150 and 200 liters/hour and the oxygen delivery is between 10 and 30 liters/hour.