US1456390A - Safety device for plants delivering inflammable liquids - Google Patents

Description

May 22, 1923. 1,456,390

M. LUDWIG SAFETY DEVICE FOR PLANTS DELIVERING INFLAMMABLE LIQUIDS Filed Aug. 31, 1921 I flak A 3Z4 w 04M WZMQL$46 q// 7 2 y Patented May 22, 1923,

MAX LUDWIG, OF BERLIN-LICHTEBFELDE, GERMANY,

ASSIG-NOR. T0. MARTINI '&

H'U'NEKE MASGHINENBAU-AKTIEN-GESELLSCI-IAFT, 0F BERLIN, GERMANY, A

CORPORATION OF GERMANY.

Application filed August 31, 1921.

To all whom it may concern.

Be it known that I, MAX LUDWIG, a citizen of Germany, and resident of Berlin- Lichterfelde, Germany, have invented certain new and useful Improvements in Safety Devices for Plants Delivering Inflammable Liquids, of which the following is a specification.

In certain plants for the storage and delivery of highly inflammable liquids, such as gasoline, the liquid has been forced to the place of discharge by the pressure of a pro tective gas which positively guarded against explosion and like dangers. In other plants, the suction system has been substituted for the pressure system, and in this case the positive protective action is generally lost. In Letters Patent of the United States No. 1,004,287 a suction system has been described in which the positive protecting action is produced by artificial means. For this purpose, the patentee without resorting to mechanical intermediate connections, employs an emergency vent left purposely on the suction side of the pump, which vent is kept closed by a liquid seal as long as there is a supply of protective gas sufficient for the safety of the plant, whereas upon the failure of the supply of protective gas the liquid seal is destroyed and the pump rendered inactive.

The present invention relates to a further development of the principle laid down in said patent, and has particular reference to plants in Which the protective atmosphere consists, not of a non-oxidizing gas, such as carbonic acid gas or nitrogen, but of air saturated with vapors of the inflammable liquid and containing a proportion of such vapors large enough to render the mixture or air and vapors non-explosive. This gas is preferably made by mixing air intimately with an excess of liquid and introducing the saturated mixture thus obtained, into the storage tank. According to my invention, this mixture on its way from the saturator, is led through an intermediate container which serves both as a means for separating the excess liquid and as a. liquid seal for the purposely provided vent in the suction conduit. As long as the saturator is working properly, this liquid seal is maintained, because the liquid of said seal is constantly replenished by the continuous separation of Serial No. 497,429.

rated; thus, after a certain lapse of time, the I liquid seal is destroyed and the liquid-drawing action of the pump interrupted by the admission of air to the suction conduit of the pump. Until this stoppage of the liquidpumping action occurs, however, the air will take up some vapors during its passage through the liquidg so that the gaseous mix? ture still contains sufiicient vapors or moisture to benon-explosive and to act as a protective gas.

Another feature of my invention consists in a suction Windchest to which, leads the seal-containing by-pass connecting at times the suction side of the pump with the upper portion or gas space of the storage tank. The end portion of this by-pass which extends into the intermediate container having the liquid seal, is utilized for indicating the level of the liquid in the storage tank. I thus provide measuring or indicating device for :the amount of liquid contained in the storage tank at anyparticular time. of this device is based on the fact thatthe height of the indicating column of liquid contained in this by-pass varies in a predetermined manner with any change in the level of the liquid in the storage tank. Reference is to be had to the accompanying drawing, which is a apparatus embodying my present invention.

The highly inflammable liquid is contained in the storage tank l from which the liquid is drawn through a pipe 2 into a suction windchest 3, whence, by the action of a pump 4, such liquid is caused to flow to the pump through a suction pipe 5, and from the pump through a delivery pipe 6 into the upper portion of a receptacle or saturator 7, the discharge end of said pipe 6 being provided with a downwardly directed opening 8 delivering a portion of the liquid into said receptacle and with a downwardly directed nozzle 9 delivering theremaining portion of the liquid into a. pipe 10. It

Will be understood that the upper end of the a very simple and efficient The operation vertical section of an pipe 10 is open to the receptacle 7, and at the time of filling this receptacle, the air displaced by the infiowing liquid passes out through this pipe, while whenever the pressure in the receptacle 7 is below atmospheric pressure, as at the time liquid is drawn oli from the receptacle 7 for instance by opening the cock shown at its bottom, an inwardly-opening check valve 11 will automatically admit air to said receptacle, in a volume corresponding to that of the liquid withdrawn. A saturated mixture of air and vapors of the inflammable liquid 'is formed in the pipe 10, and this mixture, together with any excess of liquid, passes into an intermediate container 12. The level of the liquid in this container is determined by the overflow pipe 13 which forms a return connection leading to the tank 1. The depth to which the pipe 10 dips into the liquid in the container 12, is indicated by Another pipe14, dipping into said liquid to the depth t leads from the container 12 adjacent to a scale or indicator 15 and into the suction windchest 3. With the upper portion of the container -12 is further connected a vent pipe 16, the communication of said pipe with the container being controlled by a ball valve 17 closing toward the container. The purpose of this pipe is to provide for the escape of air from the storage tank 1 at the time the latter is being filled with liquid.

The jet of liquid injected by the nozzle 9 into the pipe 10 continuously during the op eration of the pump 4 is finely atomized so that the air is not merely saturated with vapors of the liquid, but also laden with fine drops. At the same time the liquid discharged into the vessel 7 through the opening 8 will cause the level of the liquid to rise in said vessel, and since the valve 11 closes outwardly, the rising liquid will coinpress the air (or air and vapors) in the upper portion of the vessel 7, and this pressure will assist the downward flow of the stream of liquid and air through the pipe 10, and enable this stream to overcome the resistance due to the hydrostatic pressure of the column or depth of liquid t without requiring the use of suction or of a partial vacuum in the storage tank 1 thus offering a distinct advantage over prior arrangements inc-lud ing pumps and storage tanks, operating with saturation of air, which prior arrangements required a partial vacuum, or pressure below atmospheric, to be maintained in the storage tank. The protective gas contained in the upper portion of the intermediate container 12 passes to the upper portion of the storage tank 1 through the pipe 13.

The partial vacuum created in the windchest 3 by the suction of the pump 4 causes the liquid in the storage tank 1. Every va riation in the level of the liquid in the tank 1 causes a change in the pressure prevailing in the windchest 3, this pressure always corresponding to the vertical distance between the level of the liquid in the windchest and the level of the liquid in the storage tank. The height h of the liquid column in the pipe 14 is therefore always equal to the vertical distance between the levels oi the liquid in thetank 1 and wind chest 3 respectively. The pipe 14 is preferably made partly of glass, in order that the level of the liquid therein may be visible. It will be noted that when the storage tank 1 is full, the distance between the two liquid levels is at its minimum, as indicated at h, corresponding to the minimum drop of the pressure in the windchest 3 below atmospheric pressure; when the tank l is practically empty, the distance between the two liquid levels attains its maximum, as indicated at H, corresponding to the maximum drop of the pressure in the windchest below atmospheric pressure. The difference bet-ween said maximum H and said minimum h is equal to the diameter D or to the inside height of the tank 1.

The pipe 14 rises to a suflicient level to prevent the liquid from being sucked through said pipe into the windchest 3. As explained above, said pipe under normal conditions dips into the liquid in the container 12, and is sealed thereby, so that no air can enter the pipe 14 and pass into the windchest 3, to cause a possible interruption in the liquid-drawing action of the pump 4. It

will be evident that the presence, in the containe-r 12, of a sufficient amount of liquid to cover and seal the end of the pipe 14 therein, depends on the proper intimate saturation of the air entering the receptacle 7 through the inlet 11, with'the atomized liquid in suiiicient excess to replenish the amount of liquid in the intermediatecontainer 12. If'for any'reason, as on account of a clogging of the nozzle 9, the regular and proper saturation of such air should fail, this obviously will stop the furnishing of an' excess of liquid to the container 12. Since the liquid in said container is no longer replenished under these abnormal conditions,

it will be evaporated very quickly by the unsaturatedair passing through such liquid; during this passage, however, the air will take up some vapor or liquid, so that the gas passing to the tank 1 through the pipe '13 will contain some liquid in vaporized form. The liquid-drawing operation of the pump 4 can then be continued for a while, as long as the level of the liquid in the container 12 does not fall below the end of the pipe 14 therein. As soon as the liquid uncovers the said end of the pipe, the liquid seal is broken, and air will pass from the upper portion of the container 12 through the pipe 14 to the windchest 3, so that atmospheric pressure, or a pressure close thereto, will prevail in the said windchest, as well as in the upper portion of the tank 1, since there will then be an unobstructed communication between the upper-portions of said tank and of said windchest by way of the pipe 13, container 12, and pipe 14. The pressure in said portions being thus equalized, the liquid in the wind,

chest 3 Will tend to run back into the tank 1, through the pipe 2, and as soon as the liquid level falls but slightly in the windchest 3, it will partly uncover the lower end of the pipe 5, so that the pump will no longer draw liquid alone, but a mixture of air and liquid, and almost immediately (when the lower end of the pipe 5 is uncovered fully) air alone will be drawn into the pump, so that the pumping of liquid will stop automatically. Inasmuch as the pipe 10 clips into the liquid in the container 12 deeper than the pipe 14, the air passing from the receptacle 7 through the pipe 10 to the container 12, will be compelled to pass through a body of liquid, and take up vapors, on its way from the pipe 10 to the pipe 13 and to the tank 1, even after the level of the liquid in said container has fallen sufliciently to uncover the lower end of the pipe 14 and thus stop the liquid-feeding action of the pump 4. I thus insure a stoppage of such action before any air, unmixed with liquid or vapor, can reach the tank 1. It will be understood that if air, unmixed with liquid or vapors, were allowed to reach the tank 1, the proportion of air in the gaseous mixture contained in the upper portion. of the tank 1 would soon rise to such a point that the mixture would become explosive, and this is avoided by my invention.

Various modifications may be made with out departing from the nature of my invention as set forth in the appended claims.-

I claim:

1. A device of the class described, compri ing a storage tank, a pump having a suction connection to said tank to draw liquid therefrom, a saturating receptacle connected with the delivery port of the pump and having an air inlet, an intermediate container connected with said receptacle to receive air and liquid therefrom and also connected with the said tank, and a connection, normally sealed by the liquid in said container, to admit air to the suction connection of the pump and thus stop the liquid-drawing action of said pump, when the liquid-seal inlet, an'intcrmediate container connectedwith said receptacle to receive air and liquid therefrom and also connected with said tank, and a connection, normally sealed by the liquid in said container, and leading to said windchest, to admit air to the suction connection of the pump and thus stop the liquid-drawing action of the pump, when the liquid-seal is broken. 1

8. A device of the class described, comprising a storage tank, a pump having a suction connection to said tank to draw liquid therefrom, a saturating receptacle connected with the delivery port of the pump and having an air inlet, an intermediate container connected with said receptacle to receive air and liquid therefrom and also connected with the said tank, a pipe rising from the said container and normally sealed by the liquid therein, to admit air to the suction connection of the pump and thus stop the liquid-drawing action of said pump, when the liquid-seal is broken, and an indicator adjacent to said pipe, to show the level of the liquid there in and in the storage tank.

4. A device of the class described, comprising a storage tank, a windchest connected therewith, a pump having a suction connection to said windchest normally below the level of the liquid therein, a saturating receptacle connected with the delivery port-of the pump and having an air with said receptacle to receive air and liquid therefrom and also connected with said tank, a pipe rising from said container and normally sealed by the liquid therein, and connected with said windchest to admit air to the suction connection of the pump and thus stop the liquid-drawing action of said pump, when the liquid-seal is broken, and an indicator adjacent to said pipe, to show the level of the'liquid therein and in the storage tank.

5. A device of the class described, comprising a storage tank, a pump having a suction connection to draw liquid therefrom, a saturating receptacle provided with an air inlet and an air outlet, a delivery pi e leading from said pump to said receptafie and having an outlet to discharge a portion of the liquid into said receptacle and a nozzle to discharge another portion of the liquid into said air outlet, an intermediate container connected with the air outlet of inlet, an intermediate container connected said receptacle to receive air and liquid therefrom, and also connected with said tank, and a connection, normally sealed by the liquid in said container, to admit air to the suction connection of the pump and thus stop the liquid-drawing action of the pump when the liquid seal is broken.

6. A device of the class described, co1nprising a storage tank, a pump having a suction connection to said tank to draw liquid therefrom, a saturating receptacle connected with the delivery port of the pump and having an air inlet, an intermediate container having; an orertlow connection to said tank, a pipe for conducting air and liquid from said receptacle to said container and dipping into the latter below the level ae-e90 of the overflow, and a by-pass connection, likewise dipping into said container below the level of the overflow, so as to be normally sealed by the liquid therein, but to ,a smaller depth than said pipe, so that specification.

MAX LUDWIG,

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