US2390694A - Apparatus and method for charging containers with volatile mixtures - Google Patents

Description

Dec. 11, 1945. e. E. COYLE, JR 2,390,694

APPARATUS AND METHOD FOR CHARGING CONTAINERS WITH- VOLATILE MIXTURES Filed Feb. 6, 1943 WITNESSES: INVENTOR ATTOR Y Patented Dec. 11, 1945 I APPARATUS AND METHOD roa CHARGING CONTAINERS TUBES WITH VOLATEE MIX- George E. Ooyle, Jr., Southampton, Masa, as-

signor to Westinghouse Electric Corporation, slglsliarittsburgh, Pa, a corporation of Pennsyl- Application February 6, 1943, Serial No. 474,921

12 Claims.

My invention relates to a charging method and apparatus and particularly to a method or and apparatus for charging a mixture of a highly volatile liquid and a relativelynonvolatile substance from a large container into a smaller container, or into a. plurality of smaller containers,

It is an object of my invention to provide an improved charging method and more particularly to maintain the proportions of the mixture substantially constant regardless of the level of the mixture in the large container.

It is another object of my invention to maintain the proportions of the mixture substantially constant as the level in the large container drops and to accomplish this result without the use of metering devices, pumps or other moving parts, and without supervision.

It is still another object of my invention to provide an improved method for charging a mix-=- ture of an insecticide, such as pyrethrum extract, or pyrethrum extract and sesame oil, and a volatile refrigerant, such as dichlorodifluoromethane, into insecticide dispensers. It is a further object of my invention to provide improved charging apparatus for a mixture of a highly volatile liquid and a nonvolatile substance.

These and other objects are efiected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. i is an enlarged view of one of the containers or dispensers to he filled; and,

Fig. 2 is 'a diagrammatic View of the charging apparatus embodyin my invention.

The copending application of William B. Anderson, Serial No. 462,257, filed October 16, 1942, also assigned to the Westinghouse Electric 8.: Manufacturing Company, discloses and claims a. charging system for charging a volatile fluid, or a mix-' ture of a volatile fluid and a nonvolatile substance, such as pyrethrum extract, from a large container into smaller containers or dispensers for insecticide mixture, for example. In accordance with the Anderson invention, a quantity of highly volatile fluid such as dichlorodifluoromethane, and nonvolatile substances such as pyrethrum extract and sesame oil are mixed in a large container Ill (see Fig. 2) which is maintained at an elevated temperature by a heater 8. A plurality of containers or dispensers II to be filled are placed in a tank of water l2, which is lit maintained at. an elevated, temperature by a heater 9, but at a. lower temperature than container Ill. The containers H are connected to the large container it "by a manifold to through capillary tubes it associated with each container 9 i The air is not exhausted from the containers it, but the difference in temperature in container it and in dispensers it forces a predetermined amount of mixture from the large to the small containers. After the containers it have been connected. to the large containers it for a sumcient length of time, the containers H are removed and the exposed ends of the capillary tubes it are sealed ofi.

It was found, however, that in practicing the above charging method, variations occurred in the proportions of the mixture which was charged into the small containers it. In other words, the amount of volatile substance decreased as the level of mixture in the large container i dropped during a charging cycle. In charging insecticide dispensers, the cost of the main nonvolatile substance, namely, pyrethrum extract; is about twenty-five times that of the volatile liquid, so that it is important from the cost standpoint as well as from a quality control standpoint to maintain the proportions of the mixture substantially constant. In charging the containers with the insecticidal mixture set forth in the Moresaid Anderson application, the followin proportions by weight should he maintained:

Ounces Pyrethnam extract .03 Sesame oil 0.33 Dichlorodifiuoromethane 14.8?

Total 16.00

vacated by the liquid mixture, thus robbing the liquid mixture ofits volatile constituent.

' In accordance with the present invention, the loss of.volatile liquid from the mixture as the liquid level drops is automatically compensated for without the use of complicated controls, moving parts, meters and without supervision.

Referring again to Fig. 2 of the drawing, I have shown diagrammatically a tank or standpipe i5 connected by a conduit is at the-top thereof to the top of the large container l0 and by another conduit I! to the bottom of container IQ. Valves l8 and 19 are provided in theconduits l6 and I1, respectively. The standpipeiS.

must be properly proportioned as to size with example, the insecticidal mixture set forth above and the standpipe I5 is filled to the same level\ with the volatile liquid only, in this case,"di-

chlorodifluoromethane. I

The mixture .in the tank I is heated to a temperature, for example, of 140 F. and the volatile liquid in standpipe i is maintained at a temperature'of about 135 F.

Valve 18 is then opened and the vapor pressures in the tank l0 and standpipe l5 equalize through conduit I6. Valve I9 is then opened and the liquid levels in the tank l0 and standpipe I5 equalize through conduit i]. Valve 20 is then opened and the small containers H begin to fill with a resulting drop in the level of the mixture in the tank l0.

' After the valves 18 and I9 are opened and regardless of whether mixture is being withdrawn from tank I 0, vapor from the large container passes through conduit l6 and condenses in standpipe [5 due to the lower temperature therein. However, the amount of vapor condensed is immediately returned to container 10 as liquid through conduit II, the constant circulation thus maintaining a constant proportion of mixtures. This also prevents the,mixture from diffusing into the standpipe l5. As liquid mixture is withdrawn from the large container It] for filling the dispensers II, the level in the large container 10 drops, with the result that a certain amount of liquid dichlorodifiuoromethane from the standpipe l5 enters the mixture container III through conduit I! to maintain the liquid levels in both .tanks constant. The amount of liquid dichlorodifiuoromethane which enters the mixture container must equal in weight the amount of dichlorodifiuoromethane vapor which has vaporized to occupy the space in the large container Ill. vacated by the mixture, plus the amount of dichlorodifiuoromethane vapor which has vaporized to occupy the space in the standpipe l5 vacated by thedichlorodifiuoromethane liquid. The liquid dichlorodifiuoromethane mixes with the mix- -ture in tank l0 and maintains the proper proportemperature of the dichlorodifluoromethane in the standpipe I5 is 135 F. At 135 F., the den-' sity of liquid dichlorodifiuoromethane is 73.63 pounds per cubic foot and the density of the saturated vapor at 140 F. is 5.57 pounds per cubic foot. Therefore, one cubic foot of liquid dichlorodifiuoromethane will supply 13.22 cubic feet of vapor space vacated by mixture in the container 10. =However, the dichlorodifiuoromethane liquid in standpipe l5 must also supply one cubic foot of vapor to take the place of the space vacated by one cubic foot of the liquid dichlorodifiuoromethane in the standpipe. Sub-- tracting 1 from 13.22, it is seen that the mixture container II) should be approximately 12.22.

times'the diameter or cross-sectional area of the standpipe H5.

In actual practice, it was found that a large tank having an external diameter of 30 inches (with an inside diameter of 291% inches) andtwo standpipes with 6-inch internal diameters gave a ratio sufficiently close to effect compensation, standard sizes of tank and standpipes beingreadily available. I The temperature of the standpipes may be adjusted to compensate for variations.

The tank had an internal cross-sectional area of 660 square inches and the standpipes totaled 56.5 square inches, so that the tank was 11.64

'times the cross-sectional area of the standpipes These proportions may be calculated in the same manner as the above values are calculated.

From the foregoing, it will-be apparent that I have provided'an improved method and means of charging a mixture of relatively nonvolatile and highly volatile liquids from 'a large container into smaller containers wherein the proportions of the mixture remain substantially constant, and fur thermore, I accomplish this result without the use of umps, metering devices or other moving parts and without supervision.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is: 1. Those steps in the method of maintaining a constant proportion of the parts of a mixture being withdrawn from a closed container, which mixture comprises a highly volatile liquid and a relatively nonvolatile substance, which steps comprise providing a supply of said highly volatile liquid in another container so positioned that a common liquid level is maintainable in both containers, the containersbeing so proportioned that sufficient volatile liquid will be added to the mixture to compensate for the amount of volatile liquid from the mixture which goes into the vapor phase in the mixture container when mixture is withdrawn therefrom, equalizing the pressures in the two containers and placing the liquid phases of the two containers in communication.

2. Those steps in the method of maintaining a constant proportion of the parts of a mixture being withdrawn from a closed'container, which mixture comprises a volatile refrigerant and a relatively nonvolatile liquid, which steps comprise providing a supply of said volatile refrigerant in another container so positioned that a common liquid level is maintained in both containers, the

cross-sectional areas of the containers being so the two conuid level is maintainable in both containers, the

cross-sectional areas of the containers being so proportioned that sufficient volatile liquid will be added to the mixture to compensate for the amount of volatile liquid from the mixture which oes into the vapor phase in the mixture container when mixture is withdrawn therefrom, equalizing the pressures in the two containers and placing the liquid phases of the two containers in communication.

4. Those steps in the method of maintaining a constant proportion of the parts of a mixture being withdrawn from a closed container, which mixture comprises dichlorodifluoromethane and pyrethrum extract, which steps comprise providing a supply of dichlorodlfluoromethane in another container so positioned that a common liquid level is maintainable in both containers, the cross-sectional areas of the containers being so proportioned that sufilcient dichlorodifiuoro= methane will be added to the mixture to compensate for the amount of dichlorodifiuoromethane from the mixture which goes into the vapor phase in the mixture container when mixture is withdrawn therefrom, equalizing the pressures in the two containers and placing the liquid phases of the two containers in communication.

5. The steps of the method claimed in claim a wherein the mixture comprises dichlorodifiuoromethane, pyrethrum extract and sesame oil.

6. The method of maintaining a constant proportion of the parts of a mixture being withdrawn from a closed container, which mixture comprises a highly volatile liquid and a relatively nonvolatile substance, which method comprises maintaining the mixture at an elevated temperature in its container, providing a s pply of said highly volatile liquid in another container at a lower temperature than that of the mixture, said latter container being so positioned that a, common liquid level is maintainable in both containers, the crosssectional areas of the containers being so proportioned that sufilcient volatile liquid will be added to the mixture to compensate for the amount of volatile liquid from the mixture which goes into the vapor phase in the mixture container when mixture is withdrawn therefrom, equalizing the pressures in the two containers, placing the liquid phases of the two containers in communi= cation, and withdrawing the mixture from its container.

'l. The method of maintaining a constant proportion of the parts of a mixture being Withdrawn from a closed container which mixture comprises a highly volatile liquid and a relatively nonvolatile substance, which method comprises disposing a quantity of the mixture in said container, providing a supply of said volatile liquid in another container, said'containers being so positioned that a common liquid level ismaintainable in both containers, maintaining a temperature differential between the volatile liquid and the mixture such that the temperature of the mixture is higher than that of the volatile liquid, the cross-sectional areas of the containers being'so proportioned that suiflcient volatile liquid will be added to the mixture to compensate for the amount of volatile liquid from the mixture which goes into the vapor phase in the mixture container when mixture is withdrawn therefrom, equalizing the pressures in the two containers by placing their vapor phases in communication, placing the liquid phases in the two containers in free and open communication, and withdrawing the mixture from its container.

8. The method of maintaining a constant proportion of the parts 01 a mixture being withdrawn from a closed container, which mixture comprises a highly volatile liquid and a relatively nonvolatile substance, which method comprises providing a supply of said highly volatile liquid in another container, said containers being so positioned that a common liquid level is maintainable in both containers, maintaining a temperature differential between the ,volatile liquid and the mixture such that the temperature of the mixture is higher than that of the volatile liquid, the cross-sectional areas of the containers being so proportioned that sufiicient volatile liquid will be added to the mixture to compensate for the amount of volatile liquid from the mixture which goes into the vapor phase in the mixture container when mixture is withdrawn therefrom, condensing vapor of the volatile liquid and raising the liquid head in the cooler container by placing the vapor phases of the two containers in communication, transferring volatile liquid from the volatile liquid container to the mixture container by placing the liquid. phases of the two containers in free and open communication with each other, thus utilizing the diiierenw in the liquid head for said transfor, and withdrawing the constantly proportioned mixture from its container.

9. Those steps in the method of maintaining a constant proportion of the parts of a mixture being withdrawn from a closed container, which mixture comprises a highly volatile liquid and a relatively nonvolatile substance, which steps com= prise providing a supply of said highly volatile liquid in another container so positioned that a common liquid level is malntainable in both containers, .the cross-sectional areas of the contain ers being so proportioned that suficient volatile liquid will be added to the mixture to compensate for the amount of volatile liquid from the mixture which goes into the vapor phase in. the mix-= lture container when mixture is withdrawn there from and so that the correct amount of volatile fluid in the other container will vaporize as the level in said other container drops, equalizing the pressures in the two containers and placing the liquid phases in the two containers in communicaion.

10. Those steps in the method of maintaining a constant proportion of the parts of a mixture being withdrawn from a, closed container, which m1xture comprises a highly volatile liquid and a relatively nonvolatile substance; which steps comprise providing a supply of said highly volatile liquid in another container so positioned that a common liquid level is maintainable in both containers, the cross-sectional areas of the containers being so proportioned that sufflcient volatile liquid W111 be added to the mixture to compensate for the amount of volatile liquid which goes into the vapor phase in the mixture container when mixture is withdrawn therefrom and also to compensate for the amountof volatile liquid which vaporizes in the latter container when the liquid level drops therein, equalizing the pressures in the two containers and placingthe liquid phases of the two containers in communication.

11. App ratus for charging a continuously uniform mixture of highly volatile liquid and a relatively nonvolatile substance into one or more receptacles and for maintaining the proportions of the mixture uniform, which apparatus comprises,

a container for the mixture, a second container for holding a quantity of the volatile liquid only,

means adjacent the top of the containers for placing them in free and open communication to equalize constantly the pressures therein, means adjacent the bottom of the containers for equalizing the liquid levels therein, means for maintaining the temperature of the, mixture container and its contents higher than that of the second container and means for discharging liquid mixture from its container to said receptacle. i v 12. Apparatus for charging a continuously uniform mixture of highly volatile liquid and a relatively nonvolatile substance into one or more receptacles and for maintaining the proportions of adjacent the bottom'of the containers for equalizingthe liquid levels therein, the cross-sectional areaof said containers being so proportioned that volatile liquid flows automatically from the\ sec- 0nd container to the mixture container in a V014 ume sumcient to compensate for the liquid lost from the'mixture by vaporization as the levelin the mixture container drops, means for maintaining the temperature of the mixture container and its contents higher than that of the second com I tainer and means for discharging liquid mixture from its container to said receptacle.

GEORGE E. COYLE, JR.

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