# Patent

## Title
Gas lamp

## Abstract

The invention relates to an improvement for a low pressure gas lamp, and more specifically for a venturi tube in order to furnish a more efficient flame.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of provisional application 60/490,466, dated Jul. 29, 2003.


BACKGROUND OF THE INVENTION
The invention relates to an improvement for a gas lamp, and more specifically for a venturi tube in order to furnish a more efficient flame.
DESCRIPTION OF THE PRIOR ART
Gas lamps are an ancient technology. Modern usage of gas lamps is often found in camping settings or homes without electricity.
U.S. Pat. No. 5,971,026 to Beran discloses a Venture tube-like gas-air mixing valve for boilers.
U.S. Pat. No. 5,052,920 to Warner discloses a range top gas burner and air mixing apparatus.
These burner devices are not appropriate for the low pressure gas used for lighting.
SUMMARY OF THE INVENTION
The present invention provides an improved venturi tube for maximizing the efficiency of a low-pressure gas lamp. This is particularly important in homes, cabins, and other applications where the gas supply is delivered under relatively low pressures. An embodiment of the present invention uses gas at 11 inches of water column, equivalent to approximately 0.4 pounds per square inch (p.s.i.). This amount is considered low-pressure because it is less than a common required pressure of 10 p.s.i. for similar lamps. At low pressures, it is difficult to get a very bright flame from the slow supply of gas. It is an object of this invention to provide a burner tube to provide a venturi effect and produce the highest efficiency in the lamp.
By the design of the tapers and the lengths, the brightness is greatly improved and the pressure of gas required is greatly diminished. The use of low pressure has dramatic benefits for safety in camping and homes using the lamps.
The lamp also uses the venturi effect to burn to low-pressure gas more efficiently to produce a flame approximately twice as bright as similar products.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-section of a burner tube of the present invention.
FIG. 2 is a cross-section of a burner tube of the present invention showing the taper angles.
FIG. 3 is a perspective view of a completed lamp shown without a shade or wick.



DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the present invention discloses a burner tube 14 having an inlet section 1, where gas enters the burner tube. A common gas for this application is propane, however other gases are used.
As the gas enters the burner tube, a slightly tapered section 2 narrows the opening of the burner tube. At the narrowest point 3, the opening begins to open and get wider. This produces a venturi effect on the gas, drawing it through the burner tube and preventing the flame from backing into the supply line. The length of the burner tube should be between approximately 4 and 11 inches from the inlet section 1 to the turning point 12 for maximum efficiency of the venturi effect.
As shown in FIG. 2, the first tapered section 2 has an angle of taper 7 of 1 to 4 degrees. A preferred taper has been found to be 1.5 degrees. When the gas passes the narrowest point 3, the burner tube opening should be 0.375 to 0.625 inches in diameter for a typical home gas pressure using a low-pressure system. A preferred opening is approximately 0.5 inches in diameter to achieve the proper air-gas mixture.
A long second tapered section 4 expands the diameter of the opening as the gas passes through the burner tube. The angle of the second taper 9 should be approximately 2 degrees for maximum efficiency. A range of 1 to 4 degrees can be utilized with success.
After the gas passes the turning point 12, the opening tapers to slightly smaller than the size of the screen assembly 13 at the outlet 15. The screen assembly 13 is held in place by notches in the burner tube. Once the opening tapers to its narrowest point at the outlet, a first outlet taper 5 and a second outlet taper 6 help keep the flame from coming back into the burner tube. The first outlet taper angle 10 should be approximately 20 to 40 degrees, with a preferred angle of about 30 degrees. The second outlet angle 11 should be approximately 40 to 70 degrees. A mantle assembly is attached to the end of the burner tube to produce a bright light.
By example, an embodiment of the gas lamp 16 as shown in FIG. 3 was connected to a standard low pressure propane gas system having a pressure of approximately 11 inches of water column or approximately 0.4 p.s.i. The lamp produced 600 lux or 55 foot-candle at a light meter approximately 25 inches from the lamp. The prior art lamp most commonly used in the low pressure system is known as the Humphrey lamp and still sold after more than 90 years. The same testing set up was used on a Humphrey lamp and the resulting light was only approximately 75 lux or 7 foot-candle.
The preferred embodiment has been shown and described and minor variations may be made by one skilled in the art. It is intended to cover all such variations as fall withing the scope and spirit of the claims.

## Claims

1. An L-shaped burner tube for use in a gas lamp, said burner tube comprising a long and short arm, said long arm comprises:
(a) an inlet section having an opening where gas enters the burner tube,
(b) a first taper section adjoining said inlet section, said first tapered section having an opening that narrows to a first narrowest point of about 0.375 to 0.625 inches in diameter at an angle of taper of about 1 to about 4 degrees,
(c) a second tapered section adjoining said first tapered section, said second tapered section having an opening that expands from said first narrowest point to a turning point at an angle of taper of about 1 to about 4 degrees; and

said short arm comprises:
(a) a third tapered section having a wide opening at said turning point that narrows toward the burner tube outlet to a second narrowest point, and
(b) an outlet section adjoining the third taper section, said outlet section having an opening that widens towards the terminus of the burner tube at an outlet angle of about 20 to 40 degrees.

2. The burner tube of claim 1, wherein said outlet angle is about 30 degrees.

3. The burner tube of claim 2, wherein said outlet section further comprises a second outlet angle of about 40 to 70 degrees.

4. The burner tube of claim 3, wherein the opening at said first narrowest point has a diameter of about 0.5 inches.

5. The burner tube of claim 4, wherein said first tapered section has an angle of taper of about 1.5 degrees.

6. The burner tube of claim 5, wherein the length from the entrance of the inlet section to the turning point is about 4 to about 11 inches.

7. The burner tube of claim 6, wherein said second tapered section has an angle of taper of about 2 degrees.

8. A gas lamp comprising the L-shaped burner tube of claim 7.

9. A gas lamp comprising the L-shaped burner tube of claim 1.

10. The burner tube of claim 1, wherein said outlet section further comprises a second outlet angle of about 40 to 70 degrees.

11. The burner tube of claim 1, wherein the opening at said first narrowest point has a diameter of about 0.5 inches.

12. The burner tube of claim 1, wherein the length from the entrance of the inlet section to the turning point is about 4 to about 11 inches.

13. The burner tube of claim 1, wherein said first tapered section has an angle of taper of about 1.5 degrees.

14. The burner tube of claim 1, wherein said second tapered section has an angle of taper of about 2 degrees.

15. The burner tube of claim 1, wherein said first tapered section has an angle of taper of about 1.5 degrees and said second tapered section has an angle of taper of about 2 degrees.

16. The gas lamp of claim 8, which produces at least about 600 lux at a light meter about 25 inches from the lamp when connected to a propane gas source having a pressure of about 0.4 pounds per square inch.

17. The gas lamp of claim 9, which produces at least about 600 lux at a light meter about 25 inches from the lamp when connected to a propane gas source having a pressure of about 0.4 pounds per square inch.