US2180584A - Odorizer for natural gas - Google Patents

Description

Nov. 21, 1939.

w. A. GREEN ET AL ODORIZER FOR NATURAL GAS Filed May '24, 19:58

now/am 4. Green fawara Ro//e INVENTOR ATTORN EY Patented Nov. 21, 1939 UNITED STATES PATENT OFFICE ODORIZER FOR NATURAL GAS William A. Green,'Jonesboro, Ark., and Edward Rollo, New York, N. Y., assignors to Standard Oil Company of California,

San Francisco,

Calif., a corporation of Delaware Application May 24, 1938, Serial No. 209,690 3 Claims. (CL 261-39) This invention relates to devices for introducing a volatile material-having a distinctive odor into a confined flowing stream of gas, and par ticularly refers to an apparatus for accurately i ferential pressure set up therein and used to control the flow of the liquid throughasmall oriflce, with constant level float chambers, and other moving and delicate parts that are sus- 5 ceptible to leakage, corrosion and failure to operate reliably over long periods without attendance. Those evaporative types that have been used are subject to atmospheric temperature variations that change the rate of evaporation of 50 the liquid and hence the odorizing rate. 'Also, they do not continuously present an odorant of the same characteristics, particularly where the odorant material is not of a constant or nearly constant boiling mixture.

It is an object of this invention to provide an improved evaporative odorizer for natural gas, in which variations in odorant liquid level will have no effect on the odorizing rate.

Another object is to provide an odorizer that m will provide a constant odorizing rate independently of variations in atmospheric temperature.

Another object is to provide an odorizer that will have a minimum of, moving parts, that will not be susceptible to clogging or stoppage of small passages, valves, or orifices, that may be used with very low pressure differentials such as those produced by Pitot tubes in the gas line, and that will not cause changes in the composition of the odorant materials of relatively L wide boiling range being presented to be evaporated into the gas stream passing through the device.

These and other objects and advantages will be more fully apparent from the following description and from the drawing which forms a part of this specification and illustrates a preferred embodiment of the invention as applied to a natural gas odorizer;

In the drawing, Figure 1 is a diagrammatic vertical sectional view of an odorizer installation.

Figure 2 is an enlarged detail view on line Figure 3 is a horizontal sectional view online 111-111 of the float shown in Figure 2.

Referring to the drawing,'thereference numeral l0 designates a gas line in which flows the gas to be odorized, in the direction indicated 5 by thearrow. Some means of creating a pressure differential is provided, in this case a Pitot tube ll forming the high pressure connection and a simple nipple 12 forming the low pressure connection. An orifice or partly closed gate valve in line I0 could equally well be used, but a Pitot tube as illustrated has certain advantages of installation without interfering with the operation of gas line 10 that may make it desirable under certain circumstances.

'The main part of the odorizer comprises an upright tubular housing 3. preferably separable by means of a pair of bolted flanges It to permit access .to the interior. An odorant storage tank I5 is arranged near the housing l3 and is preferably mounted horizontally to give minimum variations in liquid level, as will be appar-v ent below. A pipe- IS with a shut-off valve- I1 and a flow restricting means, in this example a check valve l8 connects the lower portions of 5 housing 13 and tank I5. The check valve or other restriction insures that the odorant liquid l9 will flow only from the tank to the housing so that the odorant in the lower part of housing l3 will be uniform in composition. The upper l3, preferably provided with a packed screen or 1 other type of mist extractor 25 leads downward- 1y to nipple l2 in gas line I0. It is desirable, although not necessary, to provide shut-off valves 26 and, 21 in lines 23 and 24 respectively,

and a by-pass 28, also provided with a valve 29,

for adjustment and inspection of the device, A gage glass 30 on the side'of housing l3 indicates the level of'odorant liquid l9 therein, and may be used to calibrate the device, as will be ex- Dlained below. I A float generally designated 3| is mounted in housing l3 and acts to insure uniform contact between the gas being diverted through the device and the relatively small quantity of odorant liquid I9 in housing I3. Referring to Figure 2 it will be noted that float 31I comprises an inverted cup 32, from the center of which a long closed tube 33 extends upwardly to a distance greater than the length of pipe 23, and which servesto direct downwardly the gas which enters the housing through pipe 23. Below the lower edge of cup 32 are concentric reticulated cylinders 34 and 35, which may be of perforated sheet metal or metal wire screen construction, and with the annular space between them packed with a fibrous material 36 such as steel wool, to provide an extended surface or capillary member and insure that all gas passing around the lower edge of cup 32 will be saturated with odorant liquid.

At the lower end of cylinders 34 and 35 is a supplemental float which may be of balsa or other light buoyant material 31 covered with light sheet metal 38. A guide tube 39 extends upwardly from the opening 40 in the center of the float structure and serves to center and align the whole with pipe 23. The proportions of weight of float 3I and buoyancy of member 31 are such that the lower edge of cup 32 is preferably substantially-at the level of the odorant liquid. If

greater submergence is required, annular weights 4I guided by pins 42 may be placed on the top of cup 32 as indicated.

One of the principal disadvantages of the evapthrough evaporation, added odorant liquid automatically flows in through line I6 and valves I1 and I8, the latter serving to maintain a constant concentration of odorant in housing I3 and preventing accumulation of heavy ends or high boiling constituents of that liquid.

Float 3| will follow the odorant level as it is lowered by evaporation and will hold the sub-' mergence of cup 32 and the capillary element carried thereby constant. Gage glass 30 will indicate when tank I5 needs refilling. To calibrate the device valve I! may be closed, whereupon no more odorant will flow into housing I3 from tank I5 and gage glass 30 will indicate the rate of evaporation of the odorant I9. Suitable metering apparatus in gas line I0 (not shown) may be used to determine rate of flow in that line.

Although a specific arrangement and construe-- orative types of odorizers heretofore used was the tion of an apparatus embodying this invention variation in odorization rate with atmospheric temperature changes, high temperatures increasing the evaporation rate and low temperatures retarding it. This invention includes the provision for keeping the relatively small quantity of liquid odorant in the housing I3 at a constant temperature, preferably at a fairly high value, so that the amount of gas by-passed or diverted through the device will be small, and also so that extraordinarily high atmospheric temperatures such as are sometimes encountered, will not affect its operation. To this end, the housing I3 and, if desired, tank I5 may be insulated as shown at 43, using any desirable form of thermal insulating material,

and means are provided to heat the odorant I9 in housing I3, as by a suitable electric heating element 44, controlled by a thermostat 45 and energized from a source of electric current 46. Ohviously other means for heating, such as a gas fired device, a steam or water heater could be substituted for these heating means, if circumstances warrant.

In operation gas is diverted from line I0 through Pitot tubeI-I at a rate directly proportioned-to the gas flow in line I0, and passes through line23 into the upper end of tube 33 of float 3|, whence it is deflected downwardly into inverted cup 32 from which it passes through odorant saturated packing 36 and around the lower edge of 'cup 32 and thus becomes saturated with the has been described and illustrated above, it will be understood that many changes could be made therein without departing from the invention, and

' all such modifications as come within the scope of the appended claims are embraced thereby.

We claim:

1. An evaporative type odorizer, comprising an upright housing, an odorant reservoir, a conduit connecting the lower portions of said housing and said reservoir, means in said conduit for permitting gravity flow from said reservoir to said housing and preventing reverse flow, a float in said housing, a capillary means supported by said float to contact and be uniformly wetted by said odorant liquid independently of the level thereof, means for passing gas into said housing through said wetted capillary material above the level of said odorant liquid, a gas outlet from said housing and means for maintaining the temperature of the odorant liquid in said housing at a constant value to provide a constant odorizing rate.

2. An evaporative type odorizer according to claim 1 with the addition of a pressure equalizing conduit connecting said housing and said reservoir above the liquid level.

3. An evaporative type odorizer according to claim 1 in which said float comprises an inverted cup beneath which gas is admitted, guide means for said cup, and capillary means disposed below the lower edge of said cup and extending above the level of the liquid in said housing, through which means gas emerges into said housing and is at least partially saturated with said odorant liquid.

WILLIAM A. GREEN.

EDWARD ROLLE.

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