US1993311A

US1993311A - Method of oil fog lubrication

Info

Publication number: US1993311A
Authority: US
Publication date: 1935-03-05
Anticipated expiration: 1952-03-05

Description

W. L. SHIVELY METHOD OF OIL FOG LUBRICATION March 5, 1935.

Filed 'Jan. ll, 1950 amcas IN VEN TOR. Via/78f Z. Jfi/Z Gy B Y TT NE Y.

Patented Mar. 5, 1935 PATENT OFFICE METHOD OF OIL FOG LUBRICATION Walter L. Shively, Wilkinsburg, Pa., assignor to The Koppers Company of Delaware, a corporation of Delaware Application January 11 4 Claims.

This invention relates to the injection of oil vapor into gas mains for the creation of oil fog within the gas streams therein. In particular the invention is applicable to mains such as are used for the distribution of city gas.

In conjunction with the distribution of dry gas, the admixture of an oil fog or mist with the gas has been found desirable. The purpose of the oil fog is to create an oil moist condition for the interior of the distribution system to replace the water moist condition existing prior to the Y use of dry gas. Such an oil coating prevents dust troubles, seals minute leaks in the main and joints, prevents the drying out of jointpacking,

further reduces corrosion, alleviates naphthalene troubles, and has a beneficial efiect on meter leathers.

An oil fog is not so essential in a stream of dry gas that is passed through new mains or pipes as it is when the dry gas is passed through a system of pipes previously containing moist gas. The moisture will have brought about accumulations of rust and saturated pipe joint packings. The subsequent passing of dry gas converts the rust accumulations into dust and desiccates the packings until they leak gas.

Existing methods for the formation of a suitable fog'consist of atomization of .the oil with compressed gas or the oil saturation of a portion of a gas stream with recombination of the hot saturated gas with the main stream to produce the necessary chilling and condensation of the oil. These methods require a supply of gas at higher pressures than the main body of gas with which the fog is to be mixed.

Since oil fog equipment must often be installed in places where the power sources for the equipment to provide the gas pressure are not available or where the operation of such devices might constitute an explosion hazard, the requirement of higher pressure gas for existing means constitutes in many cases an objection to their use. It is the purpose of this invention to overcome the necemity for gas at a pressure higher than that of the gasin the system which it is proposed to lubricate.

The underlying principle of this invention is the vaporization of a suitable oil and the introduction of quantities of the vapor in the gas substantially in excess of that required to saturate the gas. The pressure created by such vaporization furnishes the pressure required to force the vapor into the gas stream. A further novelfeature of this invention is the creation of the fog in the main body of gas itself rather than 1930,. Serial No. 420,135

externally as previously done. In the drawing, Figure 1 is a vertical section of apparatus that vaporizes the oil under slight pressure;

Fig. 2 is a vertical section of apparatus that vaporizes the oil under considerable pressure;

Fig. 3 is a vertical section of apparatus that vaporizes and superheats the oil; and

Fig. 4 is an enlarged cross-sectional detail of parts shown in Fig. 2.

In each of the views a boiler 1 supplies oil val0 por through a pipe 2 to a gas main 3. The oil vapor is dispersed in a stream of gas in pipe 3 by means of a nozzle 4.

Oil is supplied to the boiler 1 through a feed pipe 5 and is vaporized by means of a gas burner 15 6 supplied with gas through a pipe 7. The source of the gas for pipe '7 may be the gas main 3.

The boiler 1 and burner 6 are surrounded by a jacket 9 and the products of combustion are conducted to the outside air through a stack 10. 20 Air is admitted to thebottom of jacket 9 through an inlet pipe 11. The burner 6 is kept from communication with its immediate surroundings because the burner and boiler 1 are located in a gas governor pit where there is a possibility of 25 accumulations of gas from leaks.

The embodiment of the invention, shown in, Fig. 1, vaporizes the oil at a pressure that is merely suflicient to overcome the pressure of the gas in the gas main 3.

The modification shown in Fig. 2 is provided with a nozzle 4 having a relatively small constrlction and the oil vapor pressure in boiler 1 may be from 5 pounds to 100 pounds per square inch. The boiler shown in Fig. 2 is provided with a pressure responsive diaphragm 12, shown enlarged in Fig. 4, which is connected to a hydrostatlc bellows 13 that in turn regulates the amount of gas passing through pipe '7 to burner 6. The boiler 1 is provided with a safety valve 14, a pressure gauge 15 and a pipe 16 for conducting any oil vapor liberated by the safety valve 14 to the atmosphere.

The modification shown in Fig. 3 difiers from the embodiment shown in Fig. l in having an ex- 4 tension of the pipe 2 formed into a superheating coil 17 that is located in the flame above the burner 6. After the oil vapor'leavesthe boiler l and passes through the superheater 17 it conr tinues through pipe 2 past a bulb 18 filled with volatile fluid. The pressure from the bulb 18 is communicated to a metallic bellows 19 which diminishes the flow of gas through pipe 7 as the temperature of the oil vapor leaving superheater 17 becomes higher.

The rate of boiling is such that quantities of oil substantially in excess of those required to saturate the gas are used. As an example, the use of from 2 to 5 gallons of gas oil per million cubic feet of gas would be contemplated with an oil of which one gallon could be carried by the gas in the vapor phase at the temperature prevailing in the distribution system. The excess of oil vapor over that required to saturate the gas must necessarily condense at ordinary gas main temperatures forming a fog or mist. I As the oil vapor is dispersed through the stream of gas in the main 3 by means of the nozzle 4 a sudden chilling of the oil vapor occurs in the ensuing eddy currents. This suddenness of chilling prevents the formation of large particles when the oil changes from vapor to liquid that would later settle readily. Since more than enough of the oil to saturate the gas is supplied the fog is quite persistent. It is removed by impingement against surfaces rather than by gravitational settling.

The oil preferably is a petroleum distillate having characteristics similar to those of absorbent or wash oils used in light-oil recovery plants. The specific gravity should range from 0.86 to 0.89 at 60 F. and the distillation range first drop 590 F. (310 C.), ml.'distilled at 650 F. (343 C.), 90 ml. distilled at 650- F. (388 0.), end point 750 F. (399 0.). The sulfur content should not exceed 0.5 per cent by weight and the carbon residue or coke should not exceed 0.05 per cent by weight. The pour point is not important and no limit is set. The viscosity will usually range from 160 seconds to 425 secondsSaybolt at'50" F. and the oil should be free of water. The oleflne content is not often important provided the oil vaporized in the gas does not form or promote the formation of gummy deposits in the transmission system, but the oleflne content will usually be less than 20% by volume; and the oil shall be presence of rust, is eliminated, pipe joint pack-' ings are kept from shrinking, and the benefit to the leather of meter bellows are a few of the advantages.

The advantages of the present method, that employs heat, over other methods is that no source of power for compressing gas is necessary,

at the point where oil fog is formed and such places are usually isolated and remote from the main gas plant.

Moreover there are no working parts to require frequent adjustment. The fuel for heating the oil is always available from the same gas-- main into which the oil fog is to be dispersed although electric heaters or any other type of heater may be used without departing from the scope of the invention as herein claimed.

I claim as my invention:

1. A method of lubricating a gas main distribution system by producing oil fog in a stream of gas comprising heating oil in an enclosed zone outside said system to vaporize the same and generate by vaporization gas pressure substantially just in excess of that of the gas in the gas main system, introducing the so vaporized oil vapor into the gas main system during the fiow of the stream of gas therethrough under the gas pressure generated bythe vaporization of the 011 against the gas pressure in the system and in amounts in excess of that required to saturate the gas to commingle with the stream of gas, condensing the oil vapor in the gas in the gas main system itself so as to form an oil fog that is carried along the system as an oil mist, and thereby lubricating the gas main system.

2. A method of lubricating a gas main distribution system by producing oil fog in a stream of relatively cool gas comprising: heating oil in an enclosed zone outside the system to produce condensible vapor from the oil and generate pressure; introducing the vaporized oil into the gas main distribution system from the heating step during fiow of the stream of gas at lower temperature in the distribution system, and against the pressure of the gas in the distribution system under the pressure created by the vaporization of the oil in the heating step, and in an amount in excess of that required to saturate the gas, and commingling the hot oil vapor with the stream of gas; and condensing the excess oil vapor in the gas main systemto form a highly persistent oil fog mist therein.

3. A method of lubricating a gas main distribution system by distributing oil in a stream of relatively cool gas in the gas main system in the form of finely divided particles constituting a fog, said method comprising heating a body of said oil in an enclosed zone outside said system to vaporize the oil and generate therewith gas pressure, superheating the vapor to produce a condensible superheated vapor, then conducting the superheated vapor under the gas pressure generated by the heating of the oil into the gas main system during flow of relatively cool gas therethrough, and condensing the superheated vapor into fog therein.

4. A method of lubricating a gas main distribution system by distributing oil in a stream of relatively cool gas in the gas main system in the form of finely divided particles constituting a fog, said method comprising, heating oil in an enclosed zone outside said system to vaporize the oil and generate therewith gas pressure greater than that of the gasin the system, then conducting a stream of the so heated hot oil vapor into the gas main system during fiow of relatively cool gas there- WALTER L. e s.