US2917068A

US2917068A - Device for transferring liquids

Info

Publication number: US2917068A
Application number: US431958A
Authority: US
Inventors: Russell B Davis
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1954-05-24
Filing date: 1954-05-24
Publication date: 1959-12-15
Anticipated expiration: 1976-12-15

Description

Dec. 15, 1959 R. B. DAVIS DEVICE FOR TRANSFERRING LIQUIDS Filed May 24, 1954 INVENTOR RUSSELL B. DAVIS 2,917,068 Ice Patented Dec. 15, 195

DEVICE FOR TRANSFERRING LIQUIDS Russell 3. Davis, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Application May 24, 1954, Serial No. 431,958 4 Claims. or. 137-205 This invention relates to equipment for transferring liquids and more specifically for transferring liquids which are dangerous by reason of their high toxicity and inflammability with a tendency to buildup an electrostatic charge. The device is particularly adapted for transferring gasoline, tetraethyl lead, and liquids of this type from tank cars to storage tanks.

In transferring dangerous liquids through pipes it is often necessary to take special precautions because of the explosive or toxic nature of the liquids being handled. For example, in transferring tetraethyl lead which is usually in the form of a mixture of this compound with scavenging agents, special safety precautions must be observed. The usual method is to apply a vacuum to the vessel into which the compound is to be transferred. As a safety measure this vacuum is produced by passing gasoline instead of water through an eductor so that the tetraethyl lead removed as vapor from the system goes into the gasoline and is ultimately used as an anti-knock agent rather than having it carried by effluent water which would present a serious disposal problem.

Because of the high vapor pressure of gasoline the vacuum produced is low, particularly at summer temperatures and is sometimes not great enough to operate a siphoning system for transferring the tetraethyl lead compound to the storage tank. A positive pressure of gas greater than atmospheric cannot be used because of the danger of getting tetraethyl lead vapor or liquid into the atmosphere through leaks or breaks.

It is often necessary to transfer such liquids from a tank car to a large storage tank of sufficient capacity to hold the contents of several tank cars. The liquid is usually transferred by means of a pipe extending from the bottom of the car to the bottom of the storage tank by maintaining a vacuum in the vapor space of the storage tank. After one carload has been transferred and it is desired to transfer a second, difiiculty may be experienced because a vacuum applied to the tank for transferring the second load will have to overcome the head of liquid already in the storage tank in addition to that overcome when the first load was introduced in order to start the pipe acting as a siphon. Similar dif ficulties arise when the siphon is broken by the accidental introduction of air during transfer. This may happen through leaks in the connections or by the formation of a vortex in the liquid. Since the tetraethyl lead compound is heavy, and the vacuum available is limited, it often happens that it is not strong enough to start the flow of the liquid or to maintain it at a suitable rate.

Herctofore, several alternatives have been employed in the transferring operation. One common expedient involves priming the line by bleeding in gasoline from the circulating system. This method, however, has the disadvantage that the tetraethyl lead compound is diluted and the blending formula is upset. Another expedient is to prime the line by an elaborate manipulation of valves which alternately connect the tank car to the eductor and then to weigh the tank. It will be obvious that this requires several operators and ofiers many difficulties. A still further method involves transferring the tetraethyl lead directly from the tank car into the gasoline circulating system, but this also has the disadvantage of upsetting the blending calculations.

It is an object of the present invention to avoid the above difiiculties by a special siphoning device more fully described hereinafter. A still further object is the provision of a device which eliminates the necessity of recalculating the tetraethyl lead content of the storage tank. A still further object of the invention is the provision of a simple device for accomplishing the above purpose which has the further advantage of eliminating any electrostatic charges which may build up in the system by a special grounding system. Other objects will appear as the description of the invention proceeds.

These and other objects are accomplished by a device which siphons a liquid from a tank car to a storage tank in which a special auxiliary standpipe consisting of two coaxial perforated pipes are located in the receiving vessel as will be more fully described hereinafter.

In the drawing, Fig. 1 is a diagrammatic view partly in section of a tank car and storage tank with the arrangement of the transferring pipes. Fig. 2 is a sectional view through the auxiliaryperforated pipes in the receiving vessel. Fig. 3 is a section along the line 33 of Fig. 2. r

In the drawing the tank car 10 is provided with a conventional tank 5 and a pipe 4 leading to the bottom of the tank for withdrawing the contents. The storage tank is indicated as 2 and is provided with the usual filling pipe shown as 8 and connected to the tank car by pipe 3 provided with valve 7. The receiving tank is also equipped with a vacuum line 9. It is also provided with an auxiliary filling pipe 19 which is connected to pipe 3 through valve 6. This pipe is provided with a flange 14 and a gland 13 for making an air-tight seal between the pipe and the tank. The portion of the inlet pipe 19 which is within the receiving tank is perforated by means of two diametrically opposed elongated perforations 11 near the top and smaller perforations 12 in the intermediate portion of the pipe. A large coaxial perforated pipe 1-is positioned around the pipe 19. This pipe is spaced from pipe 19 by means of spacers 20 which may vary in number but are usually placed at the top and bottom of pipe 1. Perforations 21 in pipe 19 are preferably disposed at right angles to upper perforations 11 and perforations 12 located near the bottom of pipe 19.

Fig. 2 shows a detailed construction of the pipes 1 and 19 and also the sealing means where the pipe enters the tank. This consists essentially of a flange 22 which is welded at 18 to the tank 2. A cover 17 fits over flange 22 and is fastened thereto by bolts. The cover 17 is also provided with a conventional gland 13 for preventing air from leaking in around pipe 19 as it enters the tank. A flange 14 is also provided on pipe 19 to connect it to pipe 3. All flanges are provided with a static bond 15 to insure. a good ground from the tank 2.

In operation the inlet pipe 8 of the receiving tank 2 is connected to the pipe 4 of the tank car by connecting pipe 3 to it by a conventional coupling 16. The auxiliary filler pipe 19 is also connected to pipe 3. A vacuum produced by a gasoline operated eductor is applied to pipe 9 and valve 6 is opened and valve 7 is preferably closed. The liquid rises in the pipe 3 and flows through valve 6 and downwardly through pipe 19 into the tank. Part of the liquid, however, passes through the perforations 12 and is caught in the space between pipes 19 and 1 and then through openings 21.

Any electrostatic charge induced upon the liquid by its flow is thus discharged upon the outer pipe and is conducted away. Once the air and vapor have been removed from the line 3, valve 6 may be closed and introducing the liquid into the receiving tank withoutdangerous electrostatic changes.

It will also be apparent that even when the receiving tank 2 is partly filled with liquid or when air has accidentally entered pipe 3 to an extent sufficient to break the siphon, the operation proceeds in the same way since there is still a vacuum connection through the perforations in pipes 1 and 19 above the liquid level of either tank;

The perforations in the inner pipe 19 may be of any size and arranged in any pattern or it may be formed of wire net or expanded metal. The outer tube 1 requires only an opening at the top above the highest liquid level and if the assembly rests against the bottom of the tank an adequate outlet for liquid at the bottom. If the assembly does not reach the bottom there is usually enough space between the outflow of the liquid without openings in the wall of the outer tube. The relative diameter of the two tubes and the total area of perforations will depend upon the rate of flow desired and the strength of vacuum available.

The present invention offers many advantages over a similar device in which the auxiliary pipe 19 is lacking. In such a case the vacuum must first overcome the pressure corresponding to the height of liquid in tank 2 before starting to raise the liquid in pipe 4 of the tank car; Accordingly the force available for transferring the liquid is much less and in many cases is not even enough to start the flow of liquid. On the other hand, with the device of the present invention the full vacuum is applied to transferring the liquid no matter what the level of the liquid in the receiving tank. Calculations show that the efiective vacuum applied in the conventional installations is increased about 43% by the present invention.

It Will be apparent that the present invention provides a method of transferring toxic and inflammable volatile liquids with a limited vacuum in a manner which is rapid, reliable and free from explosion and toxicity.

hazards. It is readily adaptable to conventional installations handling a large variety of inflammable liquids, solutions of volatile acids such as halogen acids and nitric acid, biological preparations, rubber latex and the like.

It will be apparent that many widely different embodiments of this invention may be made without departing from the spirit and scope thereof, and therefore it is not intended to be limited except as indicated in the appended claims.

I claim:

1. A device, in combination with a delivery tank and a receiving tank, for the vacuum transfer of liquids from said delivery tank to said receiving tank, said delivery tank being in siphoning relationship with said receiving tank, said device comprising a transfer pipe extending from the bottom of the delivery tank containing the liquid to be transferred to the top of the receiving tank, two valve controlled inlet pipes extending from said transfer pipe vertically downward into said receiving tank, said inlet pipes terminating at a point near the bottom of said receiving tank, one of said inlet pipes being an auxiliary pipe, the portion of said auxiliary pipe within said rece ving tank being perforated near the top and bottom, and, intermediate said top and bottom perforations, the vertically disposed portion of said auxiliary pipe having positioned therearound a co-axial pipe extending from near the top of the receiving tank to the lower end of said auxiliary pipe, said co-axial pipe being perforated at the upper end thereof, the perforations in said coaxial pipe being positioned so that they are not opposite the perforations of said auxiliary pipe, and, the perforations in said auxiliary-pipe being in communication with the perforations of said co-axial pipe.

2. The apparatus ofclaim 1 in which all parts of the apparatus are grounded.

3. A device, in combination with a delivery tank and a receiving tank, for the vacuum transfer of toxic and inflammable liquids from said delivery tank to said receiving tank, said delivery tank being in siphoning relationship with said receiving tank, said device comprising a transfer pipe extending from the bottom of the delivery tank containing said toxic and inflammable liquids to the top of the receiving tank, two valve controlled inlet pipes extending from said transfer pipe vertically downward into said receiving tank, said inlet pipes terminating at a point near the bottom of said receiving tank, oneof said inlet pipes being an auxiliary pipe, the portion of said auxiliary pipe within said receiving tank being perforated near the top and bottom, and, intermediate said top and bottom perforations, the vertically disposed portion of said auxiliary pipe having positioned therearound a coaxial pipe extending from near the top of the receiving tank to the lower end of said auxiliary pipe, said coaxial pipe being perforated at the upper end thereof, the perforations in said co-axial pipe being positioned so that they are not opposite the perforations of said auxiliary pipe, and, the perforations in said auxiliary pipe being in communication with the perforations of said co-axial plpe.

4 The apparatus of claim 3 in which all parts of the apparatus are grounded.

References Cited in the file of this patent UNITED STATES PATENTS 471,413 Bacon Mar. 22, 1892 1,312,695 Kessler Aug. 12, 1919 1,824,538 Fisher Sept. 22, 1931 2,263,826 Peniston Nov. 25, 1941 2,495,905 Pogue Jan. 31, 1950 2,602,465 Goehring July 8, 1952