Safe lighting assembly has been constructed for hostile environments. Assembly is ventilated by inert gas to prolong life of lamps. Lighting assembly contains control box, number of lamps connected in parallel, several pilot lights, and ventilating circuit. Control box is provided with components for monitoring and controlling flow of ventilating gas through lamp assemblies

Phlieger, G. A.

English

NASA Technical Reports Server

August 1973	
-	 B73-10280 
NASA TECH BRIEF 
John F Kennedy Space Center 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Pressurized Lighting System 
Vent -
	
Lamp 
Regulator	
Pressure 
Gas L::t:_ 
.
	
Figure 1. Ventilating Circuit 
S
The problem: 
Safe operation of lights in explosive gas or extremely 
humid environments requires modifications in the light-
ing assemblies. It is well known that lamps and electrical 
connectors cannot be in direct contact with explosive 
gases. An overheated lamp or a minute spark from an 
exposed connection is sufficient to trigger an explosion. 
Humidity, on the other hand, corrodes lamp sockets and 
exposed metal wiring, causing malfunctions in the 
electrical system. Protection of lights in these en-
vironments has been attempted with enclosures that 
tend to restrict air movement around the lamps which 
then frequently overheat and burn out. 
The solution: 
A new safe lighting assembly has been constructed 
for hostile environments. The assembly is ventilated by 
an inert gas to prolong the life of the lamps. 
How it's done: 
The lighting assembly contains a control box, a 
number of lamps connected in parallel, several pilot 
lights, and a ventilating circuit. The control box is 
provided with components for monitoring and con-
trolling the flow of ventilating gas through the lamp
assemblies. An inert gas such as nitrogen is supplied by a 
tank connected to the control box through a pressure 
regulator that is adjusted to approximately 15 psi 
(104 x iO N/m 2 )(see Figure 1). When the vent valve is 
closed, the gas flows through a line, through an outlet 
valve, through the lamp enclosure, and back to the 
control box. Before the operation of the light assembly, 
the entire ventilating system is purged for about five 
minutes to get rid of trapped air in the system. After 
purging, the regulator next to the pressure switch is 
adjusted so that the switch remains closed when the 
system is operating above 3 psi (20 x 10 3 N/rn2). 
An electrical schematic for the assembly is shown in 
Figure 2. Power is supplied by a 115-Vac source which 
is coupled through leads to an input power connector. A 
pilot light ("line") is connected with the power line to 
indicate when the power is being fed to the box. 
Included in the circuit is a pressure switch which 
remains closed when the pressure in the system is above 
3 psi (20 x 10 3 N/rn 2). Two pilot lights ("on" and "off') 
are used in conjunction with this switch, one indicating 
a closed position and the other indicating an open. The 
lamps are turned on by the manual switch which is also 
connected with a pilot light ("manual") that indicates 
when the lamps are on. 
• 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000280 2020-03-17T06:56:08+00:00Z
115V 
(\) S 
Manual 
Pressure	
-
Switch 
Switch
0 
Off Pilot 
Light 
"Line"
 (	 •Pilot ( PilotT Light Light	 Pilot 
"Off" "On"	 Light 
- "Manual"
¶	
2? 
Lamp	 Lamp	 Lamp 
A	 AI 
Figure 2. Electrical Schematic for the Lamp Assembly 
Because the lamps are fluorescent, they are enclosed 	 Patent status: 
in shielding which prevents radio frequency interference 	 This invention has been patented by NASA (U.S. 
(RFI) with any electronic equipment that may be	 Patent No. 3,673,424). Inquiries concerning nonexclusive 
operating in the vicinity,
	
	
or exclusive license for its commercial development 
should be addressed to: 
Note:	 Patent Counsel 
Requests for further information may be directed to: 	 Kennedy Space Center 
Technology Utilization Officer 	 Code AD-PAT 
Kennedy Space Center	 Kennedy Space Center, Florida 32899 
Code AD-PAT 
Kennedy Space Center, Florida 32899 	 Source: G. A. Phileger 
Reference: TSP73-10280
	
	
Kennedy Space Center
(KSC- 10644)
. 
B73-10280	 Category 02 


Pressurized lighting system

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