US2919981A - Apparatus for odorizing liquefied gas - Google Patents

Description

Jan. 5, 1960 J. B. CALVA 2,919,981

APPARATUS FOR oooarzmc LIQUEFIED GAS Filed Nov. 25, 1951 2 Sheets-Sheet 1 INVENTOR 5 I y 13mg ATTORNEY Jan. 5, 1960 J. B. CALVA 2,919,981

' APPARATUS FOR ODORIZING LIQUEF'IED GAS Filed Nov. 23,- 1951 2 Sheets-Sheet 2 IN VENTOR Java Ca/a/ BY 7.8mm?

ATTORNEY said above, when the last portion of gas United States PatentO 2,919,981 APPARATUS FOR ODORIZING LIQUEFIED GAS Jose B. Calva, Minneapolis, Minn., assignor of one-half to George W. Benz, St. Paul, Minn.

Application November 23, 1951, Serial No. 257,903

4 Claims. (Cl. 48-195) This invention relates to an improvement in method and apparatus for odorizing gas obtained from liquefied petroleum gases and deals particularly with a procedure to odorize the gas as it leaves a liquefied gas container. 1 For some years it has been recognized that gas obtained from liquefied petroleum gas, to which an odorif- 'erous substance has been added, is not uniformly odorized as ensues from its container. It has been further observed that when a container of liquefied petroleum gas is full, the ensuing gas is practically free from odor while, when the container is approaching the condition of emptiness, the ensuing gas possesses a very strong odor.

The cause of the unevenness of intensity of odor is the disparity in the rate of evaporation of the liquefied petroleum gas and the odorant added to it. Increasing the concentration of odorants to the liquefied petroleum would be one way to insure the presence of odor in the first portions of gas from a full container but such a procedure, aside from being limited by the solubility of odorants in liquefied petroleum gases, would greatly increase the intensity of odor of the last portions of gas; a condition that is already a source of complaint from the home users of liquefied petroleum gases.

The lack of uniformity in the intensity of odor in the gas ensuing from a container has many disadvantages which may lead to serious consequences. A person noticing the relatively strong odor of the gas when the tank is relatively empty might well not notice the relatively less noticeable odor of the gas of a new tank. Thus when the liquefied petroleum gas container is nearly full a person is less likely to notice escaping gas by its odor than if the tank is relatively empty. Furthermore, as

in a tank is dispensed, its odor is so strong as to be objectionable even when escaping in extremely small quantities.

When gas escapes without being detected, it often accumulates in confined spaces giving rise to explosive mixtures. These mixtures when ignited by flame, spark or ember, produce explosions that because of their intensity are frequently destructive to life and property.

Since explosive mixtures of gas and air are invisible, the only Way to detect their presence is by a certain odor that is imparted to the otherwise odorless mixture. One inventor has proposed to add odorants to the gas stream but his procedure otfers so many disadvantages that to the best of my knowledge, to this date, his invention has not been used by the liquefied petroleum gas industry.

One of the objects of the present invention is to provide a catridge of suitable shape and size consistent with the capacity and rate of demand of the gas system where it is to be installed, said cartridge being composed of a material possessing capillary properties toward odorants and being impregnated with a sufiicient amount of an odorant to amply odorize,'uniformly, the gas produced from the liquefied-petroleum gas in a given container.

In the case of portable liquefied petroleum gas containers the cartridge is placed a suitable cavity in the 2,919,981 l atented Jan. ,5, 1,960

Another object of the present invention is to provide a means of assuring the consumer that the gas heis going to draw from a liquefied petroleum container will be properly odorized; this is accomplished by sealing the cartridge impregnated with odorant in its proper cavity by means of a fracturable membrane or metallic seal to be broken at the time the cylinder is connected to the piping system that is to supply the gas.

Still another object of this invention is to emphasize the presence of gas leaks from piping systems, so as to avoid the formation of gas explosive mixtures without being noticed. This is accomplished by the high concentration of odorant that will be present in gas that flows at a low rate, since the amount of odorant in the gas, according to my procedure, is due to the vapor pres sure equilibrium between the liquid odorant impregnating the capillary structure of the cartridge and the gaseous phase surrounding it.

The provision of a high concentration of odorantfin gas leaking slowly from a gas system is the reverse of the situation normally encountered in dealing with bottled gas containing liquid odorant. When such a gas tank is closed, the odorant tends to condense on the tank walls, and to separate out from the petroleum gas. A small leakage of gas from the tank would accordingly remove gas containing very little odorant. A rapid removal of gas from the tank would tend to increase the odorant content. However, as gas explosions are usually caused by slow leakage of gas, rather than by rapid escape thereof, the applicants process of over odorizing gas leaking slowly from the tank isof utmost importance in preventing accidents.

These and other objects and novel features of my invention will be more clearly and fully set forth'in the following specification and claims. 1

In the drawings forming a part of the specification:

Figure l is a diagrammatic view showing the upper end of a liquid gas tank and showi g the valve arrangement connected thereto.

Figure 2 is a sectional view through the valve showing the cartridge chamber connected thereto.

Figure 3 is a sectional view showing a modified form of valve showing the cartridge chamber formed therein.

Figure 4 is an elevation view of a gas tank valve partly in section showing the manner of sealing the odorant cartridge when the tank is being stored or transported prior to use.

Figure 5 is an end view of a modified form of odorant cartridge. I,

Figure 6 is an end view of another modified form of cartridge. v I

Liquid gas of the type commonly used for-cooking, heating and other purposes, is often sold in, storage tanks. The gas is sold in liquid form and gradually boils as gas is dispensed sothat a constant gas pressureis maintained throughout the life of the gas supply. Gases sold in this way are normally. hydrocarbon; gases. such .as butane, propane, pentane, and the like. i

It is usual practice to mix theliquid gas with anodor'ant capable of producing a gassy odor to the mixture. Some of the materials which have been used for this purpose are methyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, and amyl mercaptan, as well as certain of the sulphides suchv as ethyl sulphide, propyl sulphide, andbutyl sulphide. liiowever these odorants donot have the samelvapor pressure as t-he g'a's "and-therefore do not evaporate. i agine,mummies of the mixture'of liquids as' readily as the gas. ,As a.

poorly odorized. When the gas is dispensed the percentage of odorant in the mixture increases until the last portion of gas to be removed from the tank is very highly odorized. This situation is obviously undesirable.

In Figure l of the drawings I disclose a gas tank of any suitable size and shape. This tank 10 is provided with a collar or 'boss 11 welded or otherwise attached thereto. This boss 11 provides an internally threaded opening 12, indicated by dotted lines, which leads through the top of the tank into communication with the interior thereof. The outer periphery of the boss 11 'is threaded as shown in elevation at 13 to accommodate a sleeve which is threaded onto the top of the tank to overlie the valve during transportation and handling so as to prevent any strain from being exerted against the valve which may tend to loosen the joint between the valve and the tank or to injure the valve. The protecting sleeve in its usual form is not illustrated in the drawings.

The valve is indicated in general by the numeral 14 and is disclosed in more detail in Figure 2 of the drawings. The valve 14 includes an externally threaded tubular shank 15 which is threaded into the aperture 12 and is sealed with respect thereto. A movable valve plunger 16 is supported for longitudinal sliding movement within the body of the valve. This valve body includes a tubular sleeve portion 17 which is aligned with the shank 15 and is internally threaded at its upper extremity. A nut 19 is provided with an integral sleeve 20 which is externally threaded to fit into the sleeve 17. The sleeve 20 is designed to clamp against the marginal edge of a centrally a-pertured diaphragm 21 which seats against a shoulder 22 forming a part of the valve body. Thus the diaphragm 21 is marginally clamped and sealed so as to hermetically seal the lower portion of the valve from the upper portion thereof.

The nut 19 is internally threaded to accommodate a threaded shank 23 having an enlarged head 24 at its lower extremity. This head 24 is provided with a T- shaped slot 25 at its lower extremity to accommodate the enlarged head 26 of the valve plunger 16. The valve plunger 16 includes an externally threaded shank 27 which accommodates a clamping nut 29 and washer 30. The valve plunger is provided with a shoulder connecting the threaded shank 27 with the larger diameter lower end 31 of the plunger. The clamping nut 29 clamps the washer against the diaphragm 21 and holds this diaphragm firmly against the shoulder between the two different diameter portions of the valve plunger to seal the valve plunger to the diaphragm. Thus the valve plunger may move vertically within predetermined limits while still remaining sealed to the plunger and the valve casing.

A hand wheel 32 is secured to the upper end of the shank 23 and is held from rotation relative thereto. Rotation of the hand wheel causes the shank 23 to be threaded upwardly or downwardly in the nut 19. This action moves the valve plunger 27 upwardly and downwardly in the valve chamber. The large diameter lower end 31 of the plunger 16 is socketed to accommodate a resilient block 33 of material which acts as the valve.

A relatively smaller diameter passage 34 is provided between the shank 1S and the upper portion of the valve body. This small diameter portion terminates in an upwardly directed circular rim or bead 35 against which the resilient block 33 may seat. The lower portion of the valve may be closed off from the upper portion thereof by the resilient block 33.

A boss 36 extends laterally from the shank 15 above the level of the threaded portion thereof. This boss 36 is externally threaded to accommodate a cap 37. The cap 37 is provided with perforations 39 therethrough. A partition wall 46 having a passage 41 therethrough is rovidedat the base of the boss 36. A circular rim 42 is provided on the partition wall to extend outwardly therefrom about the periphery of the passage 41. A

valve piston 43 is slidable within the hollow boss 36 and includes a resilient block 44 designed to seal against the rim 42. A spring 45 is interposed between the cap 37 and the valve piston 43 to urge this piston in sealing relation against the rim 42. This valve piston acts as a safety valve and the spring 45 may compress under sufiicient pressure to permit the escape of gas from the valve. Thus if excessive pressure builds up within the gas tank the safety valve may operate to permit the escape of some of the gas. As the gas tanks are normally located exteriorly of buildings and as any escape of gas through the safety valve is extremely unlikely, there is little danger of explosion or fire in the event the safety valve opens to vent the excessive pressure.

The valve body above the reduced diameter passage 34 is provided with a laterally extending tubular boss 47 which is internally threaded. This boss is usually used to accommodate the fitting of a tubular conduit leading to the pressure regulator valve. However, in the present instance the boss 47 is to accommodate an adapter 49 of the type illustrated in Figure 2.

The adapter 49 includes a generally cylindrical tubular portion 50 which is externally threaded to fit into the boss 47. This cylindrical portion 50 is provided with a tapered end 51 designed to fit against a correspondingly tapered surface 52 within the sleeve 47 to form a gas tight joint between these parts. The inner surface of the sleeve 50 is designed to accommodate an odorizing cartridge 53 which comprises a body of material possessing capillary properties toward odorants and capable of being impregnated with a sufiicient amount of the same so that odorant will be given ofi throughout the life of the tank of gas.

The fitting 49 also includes a sleeve 55 which is interna'lly threaded as indicated at 56, the internal threads 56 being of the same size and dimensions as the threads of the boss 47. The fitting 49 is also provided with a tapered inner surface 57 against which the enlarged tapered end 58 of a connector 59 may engage. The connector 59 is of proper size to fit either into the sleeve 47 or into the internally threaded end 56 of the fitting 49 to form a gas tight joint in conjunction therewith. A threaded sleeve 54 slidably encircles the connector and threads into the fitting 49 to seal the enlarged end 58 of the connector 59 in place.

The odorizing cartridge is impregnated with an odorant material capable of imparting a gassy odor to the gas. For example the cartridge 53 may comprise a tubular cylindrical body of cotton or other material possessing capillary properties toward the odorant and which is impregnated with a mercaptan or other suitable odorant. Thus as the gas passes through the valve, it picks up odorant and the gas is accordingly uniformly odorized.

In order that the fitting 49 may be employed on tanks of conventional design, I may employ a collar 60 of the type illustrated in Figure 1 upon the externally threaded boss 11. of the tank. This collar 60 is internally threaded to accommodate the threads 13 of the usual boss 11. The collar is externally threaded to engage a cap or sleeve 61 shown in dotted outline in Figure l of the drawings and used for protecting the valve 14 during handling or transportation. In other words, as the tank is shipped or delivered a cap 61 may be applied thereto to protect the valve. This cap is shown in dotted outline in Figure '1 of the drawings, and in Figure 4 of the drawings, as it is normally removed before the tank is attached to the fittings forming a part of the piping of the house or building.

In a device of this type it is essential that the odorizing cartridge be inserted when the tank is filled with liquid gas and that the cartridge remain in place throughout the life of the liquid in the tank. Accordingly a .seal is provided which is applied when the odorant cartridge is inserted and which is not broken until the full tank is connected. As a result the cartridge forms a part of the equipment furnished the customer and is always in place throughout the use of the gas. This is extremely important from a safety standpoint for the liabilityin case of accident may be considered to rest upon the producer of the gas and the producer can not afford to be responsible for the failure of a service man to place an odorant cartridge in the service line at the time each new tank of gas is installed.

As indicated in Figure 4, the fitting 49 is provided with a cap 62 including a disc-shaped end 63 and a substantially cylindrical skirt 64. The seal is made of plastic or other material, and is shrunk onto the end of the fitting 49 to provide a gas tight seal. The odor of the cartridge is thus not noticeable until the seal is broken.

Figure 1 indicates in general a pressure regulating valve 65 which is connected to, the gas line 66. This valve 65 is provided with an inlet conduit 67 at the tip of which is connector 59 which is fastened to the fitting 49 by the threaded sleeve 54 in the manner previously described. When the tank is in place, the conduit 67 forms a connection between the valve 14 and the pressure reducing valve 65 before the valve 14 is opened. Once this valve is opened the tank is directly connected to the gas line of the house or other establishment.

Obviously the connection 67 may employ automatic valves or other mechanisms which may disconnect the pressure regulating valve 65 from one tank and connect it to a second tank. However, in any event the coupling or fitting 49 remains connected to the valve 14 in the manner in which it is furnished from the producer.

In Figure 3 of the drawings I disclose a modified form of valve which is indicated in general by the numeral 69. For the most part the valve 69 is identical with the valve 14 previously described. Accordingly most parts of the valve 69 are not given separate identifying numerals. The main point of difference between the valves 14 and 69 lies in the elongated sleeve like boss 70 which is provided in place of the shorter boss 47 of the valve 14. This boss 70 comprises an elongated sleeve 71 having an internally threaded portion 72 terminating in a tapered portion 73 similar to the threaded portion of the sleeve 47 and the tapered portion 52 of the valve 14. However, internally of the tapered portion 73, I provide a cylindrical portion 74 of proper size to accommodate an odorizing cartridge 75 similar to the cartridge 53. This odorizing cartridge 75 is inserted in place within the valve at the time the tank is filled with gas and remains in place throughout the life of the gas. With this arrangement the fitting 49 may be eliminated.

The open end of the boss 70 is sealed in the manner illustrated in Figure 4 after the cartridge has been inserted. As the tanks are usually filled through the boss 47 or 70 of the valves, the cartridge is usually not inserted until after the tank has been filled. The seal remains unbroken until the tank is attached to the pressure regulator valve 65.

In the foregoing description, I have described an odorant cartridge which is cylindrical in form and which has an unobstructed axial passage therethrough. It is my intention to provide a cartridge which minimizes any reduction in pressure between its end so that the gas may flow through the cartridge substantially without losing velocity. In place of the sleeve-like cartridges previously described and identified by the numerals 53 and 75, I may employ a cartridge of the general type illustrated in Figure 5 of the drawings. This cartridge is preferably cylindrical in shape so as to fit snugly within the chamber provided either in' the fitting 49 or in the chamber 74 of the valve 69. The odorant cartridge 77 is provided with a series of angularly spaced unobstructed apertures 79 extending londitudinally through the cartridge. By varying the diameter or cross-sectional area of the apertures 79, the amount of surface of the odorant cartridge exposed to the gas as it travels through the cartridge may be regulated. If the gas system uses gas at a relatively low rate, the size of the cartridge apertures may be reduced without losing the desired odorant effect. At the same time if the gas system consumes gas at a relatively high rate, the area of the openings may be enlarged to compensate for a quicker flow of gas and at the same time to present a larger surface of contact between the gas and the odorant cartridge. The length of the cartridge may also be varied in accordance with its intended use.

Another form of cartridge which may be used in place of those previously described is indicated in Figure 6 of the drawings. The cartridge shown in this figure comprises a generally cylindrical body of material having peripheral angularly spaced unobstructed notches 81 in its exterior surface extending throughout the length of the cartridge. As a result the gas may travel between the cartridge and the walls of the chamber in which the cartridge is enclosed. The notches may be varied in width and depth to produce the desired area of contact between the gas and the odorant. Similarly the cartridge may be star shaped having V-shaped notches between the peaks at the periphery of the body. The material used must possess capillary properties for the particular odorant used and must be capable of retaining sufficient odorant to properly odorize the complete tank of gas.

The operation of the odorizing system is believed obvious from the foregoing description. When the gas is being drawn through the odorant cartridge it retains sufficient odorant to properly warn persons in the event gas escapes. As the gas travelling through the cartridge is in gaseous form, it will readily pick up the odorant with which the cartridge is impregnated. Furthermore, as the cartridge is located between the tank and the pressure regulating valve, the pressure of gas passing through the cartridge is always substantially constant. I have found that the gas is odorized substantially uniformly throughout the life of the gas within the tank if the cartridge is of proper proportions. Furthermore, as the cartridge is located within a portion of the equipment permanently connected to the tank, there is substantially no danger of leakage of gas unless the gas has first passed through the odorizing cartridge.

It is important to note that an extremely slow flow of gas through the cartridge will result in odorizing the escaping gas to a greater extent than would otherwise be the case. When the gas remains stationary in the vicinity of the cartridge, there is a small amount of gas which is more highly odorized than 'when the gas is passing through the valve. As a result if gas leaks from the system, at an extremely low rate, the escaping gas will be more highly odorized than where the gas is being dispensed in the usual manner. This is important as a gas leak usually results in gas escaping at a very slow rate.

In accordance with the patent statutes, I have described the principles of construction and operation of my method and apparatus for deodorizing liquefied gas, and while I have endeavored to set forth the best embodiment thereof, I desire to have it understood that obvious changes may be made Within the scope of the following claims without departing from the spirit of my invention.

I claim:

1. A device for odorizing gas designed for use in conjunction with a gas tank containing liquified gas and a gas dispensing line, the apparatus including a valve directly connected to said gas tank, said valve including an inlet and an outlet, a valve element between said inlet and outlet, an open-ended hollow tubular fitting having an enlarged bore and secured to said outlet for connecting said valve to said gas dispensing line, and an odorant cartridge fitting closely within said enlarged bore in said fitting and accessible for removal and replacement through an open end of said fitting, said cartridge comprising a small cylindrical body of material having unobstructed aperture means for passage of gas and possessing capillary properties toward an odorant, and odorant impregnated therein.

. 2. As-a new combination, a source; of uniformly detectably odorized gas comprising: a pressure tank. contain.- ing a quantity of liquified gas under pressure; a valve body including, avalve mechanism for releasing gas from said tank, an outlet for connection to a pressure-reducing valve of a dispensing system, and a chamber for an odorant cartridge lying within said valve body between said outlet and said valve mechanism and accessible from said outlet; and a removable rugged odorant cartridge including a vaporizable odorant in an amount sufficient to impart detectable odor to the entire quantity of gas contained in liquified form in said tank, said cartridge fitting within said chamber and provided with at least one. unobstructed aperture means for unobstructed passage of gas therethrough, said aperture exposing to the gas stream, a cartridge area just sufficient to ensure adequate odorization of said gas stream.

3. The combination defined in claim 2 in condition for storage'and transport and includingremovable sealing means at said outlet for preventing loss of vaporizable odorant under storage and transport conditions.

4. The combination defined in claim 2 in which the source of odor is a liquid odorant capillarily held within a rugged fibrous cartridge capable of being inserted into and removed from the valve chamber- Without breakage.

References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. A DEVICE FOR ODORIZING GAS DESIGNED FOR USE IN CONJUNCTION WITH A GAS TANK CONTAINING LIQUIFIED GAS AND A GAS DISPENSING LINE, THE APPARATUS INCLUDING A VALVE DIRECTLY CONNECTED TO SAID GAS TANK, SAID VALVE INCLUDING AN INLET AND AN OUTLET, A VALVE ELEMENT BETWEEN SAID INLET AND OUTLET, AND OPEN-ENDED HOLLOW TUBULAR FITTING HAVING AN ENLARGED BORE AND SECURED TO SAID OUTLET FOR CONNECTING SAID VALVE TO SAID GAS DISPENSING LINE, AND AN ODORANT CARTRIDGE FITTING CLOSELY WITHIN SAID ENLARGED BORE IN SAID FITTING AND ACCESSIBLE FOR REMOVAL AND REPLACEMENT THROUGH AN OPEN END OF SAID FITTING, AND CARTRIDGE COMPRISING A SMALL CYLINDRICAL BODY OF MATERIAL HAVING UNOB-

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