US 2928436 A
Description (OCR text may contain errors)
March l5, 1960 B. WENDROW ETAL VAPOR SEALED LIQUID CARRIERS Filed Sept. 17, 1956 Afl/d] n4-waz: dfi/mm hex/.010114 2,928,436 VAPOR SEALED LIQUID CARRIERS Bernard Wendrow. Long Beach, and Raymond F. Labory, San Gabriel, Calif., assignors to Union Oil Company of California, Los Angeles, Calif., a corporation of California Application September 17, 1956, Serial No. 610,275
4 Claims. (Cl. 141-105) This invention relates to the dispensing of liquids and particularly to apparatus for liquid dispensing and simultaneous vapor recovery. More particularly this invention relates to an improved apparatus for the transfer of volatile liquids of relatively low boiling point such as in the iilling of vessels therewith under circumstances involving the generation and/or displacement from the vessel of relatively large quantities of vapors.
Light, low boiling liquids present considerable problems from air pollution and tire explosion hazard stand points during the transfer thereof from one vessel to another. Such liquids comprise solvents including the low molecular weight alcohols, ketonesand esters, and including the light hydrocarbon solvents such as naphtha, and the relatively low boiling internal combustion engine fuels such as gasoline. These liquids have relatively high pressures under normal temperature conditions and evaporate very readily, especially during agitation. The vaporization occurs at substantial rates from vessels open to the atmosphere and occurs at considerably higher rates when the liquid is in motion such as during the introduction of liquid into the vessel. Exceedingly high rates of vaporization occur when the liquid is introduced into the vessel under conditions which cause it to splash either against the bottom or walls of the vessel or against the liquid level therein.
Under these conditions of liquid transfer where vaporization takes place, serious hazards due to possibility of tire and/or explosion, fume generation, and air pollution present themselves. Furthermore, these light solvents are frequently very expensive and any vaporization loss is expensive and wasteful of materials. yOften local regulations govern the type and amount of such vaporized materials which can be handled in the open air in order to minimize the possibility of air pollution or the damage from tire or explosion.
One specific application of this invention is in the delivery of volatile liquids from tank trucks, railroad cars, tank ships, and other liquid carriers into other vessels such as storage tanks. Particularly this invention is applicable to the delivery of gasoline in tank trucks to the underground storage drums at service stations. This is not to be considered limiting however, since the same invention is well applied to the delivery of such volatile fuels such as gasolines, solvents, and the like from any portable container to any stationary or nonstationary storage tank.
Tank trucks and railroad cars, which will be hereinafter discussed by way of illustration only, have liquid capacities which vary from about 4,000 to 8,000 gallons for trucks, while railroad cars have capacities on the order of from 30,000 to 50,000 gallons. In emptying liquids from such tanks, and depending upon the circumstances and the manner in which they are unloaded, displaced vapors evolve from the tanks being filled amounting to between about 0.5 and about 5.0 gallons of vaporized material per thousand gallons of liquid unloaded.
States yPatent 2,928,436 Patented Mar. 1,5, 1969 ice Beside constituting an economic loss, there is thus gcnerated a serious fire and explosion hazard with flammable liquids and in many cases atmospheric contamination occurs which is highly undesirable. l
Such apparatus as described below according to this invention is efficiently operated in conjunction with irnproved stationary vapor recovery equipment presently available at tank truck and tank car loading stations. The vapors displaced at the delivery point into the carrier tank by the meansof this invention are againl displaced from the carrier tank when it is reloaded at the liquid source. This displaces the recovered vapors into suitable vapor treating equipment whereby the volatile liquid is recovered from the displaced air. At petroleum relineries this displaced vapor can be displaced from the carrier tank on relling into vapor recovery equipment consisting of oil adsorbers, solid adsorbent treaters, compression and cooling systems, and the like to recover the gasoline vapor.
It is therefore a primary object of the present invention to provide improved liquid carrying and delivery equipment which is sealed against vapor loss.
It is a more specic object of this invention to provide improved tank truck and railroad car apparatus for the delivery of volatile and flammable liquids whereby the complete recovery of evolved vapors is permitted.
Other objects and advantages of the present invention will become more apparent to those skilled in the art as the description and illustration thereof proceed.
Brieliy the present invention comprises a portable delivery tank, such as tank truck or railroad car ortank ship, operated between a source of volatile liquid and a delivery point for the liquid. The delivery point includes a stationary storage or receiving tank provided with a conventional liquid inlet, and ordinarily provided with a vapor vent or escape line. According to this invention a relief valve, adjusted to open at a low pressure of 0.1-5.0 p.s.i., is added to the existing vent line and a new vapor outlet line is added, usually disposed adjacent to the liquid inlet.
The portable delivery vessel is modified to provide a vapor header communicating all individual liquid cornpartments which may be provided in the vessel and to this vapor header is provided a new vapor connection.,
Both the delivery vessel and the storage vessel involved in the apparatus of this invention are thus provided with a liquid and vapor connection preferably disposed adja cent each other. Two portable connections such as hoses or the like then connect the liquid connections and the vapor connections respectively. When the liquid is then drained or pumped from the delivery vessel into the storage vessel, the displaced vapor from the lreceiving vessel passes back through the vapor connections into the increased vapor space present in the delivery vessel.v in most cases there need be no vapor escape whatsoever and all the vapor displaced from the storage vessel accumulates in the delivery vessel. The portable delivery vessel is returned to the source at which point it is refilled thereby deliverying the recovered vapors back to suitable treating facilities to separate volatile materials in the vapor phase from this volume of vapor. Only under unusual circumstances, as Where excessive turbulence occurs or where liquid delivers into a warmer storage tank than the delivery tank from which it is taken, is any material quantity of excess vapor generated which need be vented. In these instances` the excess vapor is` is lost to the atmosphere to constitute a hazard or ujs;
v delivery tank connected to a stationary storage/tank utilizing 4the improvements of Vthe present invention,
Figure 2 isan end vicw of the delivery tank showingl the disposition of the vapor manifold and the vapor connection,
Figure 3 is a detailed cross section view of one for of baille employed atthe points of` connection between the vapor manifold Aand the individual compartments in the delivery tank, i
Y Figure 4 is a view of the apparatus in Figure 3 taken at right angles thereto, and
.FigureS shows an alternate means for preventingrliquid entry into the vapor manifold.
Figure 6 shows still another means for preventing liquid entry into the vapor'tnanifold.
Referring now more particularly to Figure '1, the appa` ratus shown is illustrative of the system of liquid delivery according'to the present invention as applied to the de-V livery of gasoline from tank trucks and trailers to underground storage drums at gasoline service stations. Figure 1 tank trailer 16 drawn by truck 12 Vis provided "appease 4 when the hose is connected and after the truck has been positioned to deliver its liquid cargo.
, Referring now more particularly to Figure 2, an end i viewof the tank trailer V10 in Figure 1 is shown illustratwith a plurality ofcornpartments 14, 16, 18, 20, and 22.4
These are separated one from the other by several dished heads 24. Each compartment has a separate liquid inlet or loading hatch 25. In the dome 26 of trailer 10 is provided an elongated vapor manifold 28 which opens through a series of connections 30 into each compartment.
Trailer 10 is provided along its lower side with meter and unloading valve compartment 32. Within this'compartment is a vapor'inlet connection 34 and liquid outlet connection 36. The vapor inlet communicates through `isshown extending down through tank 42 to a point near the bottom thereof and this serves to minimize vapor generation so that the vapor displaced ordinarily from Ysuch a tank is very nearly equal in volume to the volume of liquid introduced into the tank.
. The liquid from the tank trailer 10 is discharged through its liquid outlet36 and through a flexible hose' or conduit indicated generally as 52 connected to liquid inlet line-44 of the underground storage tank 42. 1As
this liquid is quietly discharged Vinto the storage tank, liquid level 54 therein rises reducing the vapor space above it and displacing a substantially equal volume of vapor through vapor outlet 5t), through vapor hose Y56, through :vapor Vinlet 34 on tank tralier 10, and through the vapor header 28v to the compartment or compartments being` emptied.
In the preferred Vrnodication o f this invention the already existing liquid inlet 44'onj the delivery tank 42 and the'already existing outlet 3,6 on the tanktrailer 10 is used `in this invention together with the flexible hose for connecting thesetwo points. the vapor llow patha, check 4valve is provided which permits "ilow only out of the stationarytank into the tank trailer. Preferably this check valve is disposed at Vthe vapor inlet on the tank trailer and the flexible vapor hose connected thereto is provided'with anV actuating piuwhich serves to open the vaporinlet tothe" truck only;V
At some-point in n ing vapor dome 26 and showing the disposition of vapor header 23,V and baffles 3i) therein. Vapor inlet line 38 opens upwardlythrough tank 10 to header 28 from the Vinlet connection 34 in pump and unloading valve compartment 32.
Referring now rnoreA particularly to Figure 3 an elevation viewin partial cross section of baille means indicated generally at 30 in Figures 1 and'2 is shown.V Hereinthe end View of vapor manifold 28 is indicated provided with a downwardly opening connection 60. A
short section of Vsteel tubing 62 is threaded into the downwardly opening connection 60. From the steel tube a transverse Vbaille 64 provided with a vertical circular flange 71 and furtherprovidedr with openings 66 in its lower surface is suspended by means of several steel rods 68. The direction of vapor ,flow from header 28 past this baille means and Vinto the individual tank compartments is indicated by 4the arrows. |The purpose of this baille is Yto prevent any of the liquidcontents present in each of the compartments from vsplashing into the vapor header and impeding' entry of the vapor through the header. -Any liquid readily drains from' lconnection 60 t through openings 66. d
In Figure 4 is shown a view at right angles of the device shown' in Figure 3. Tubular element 642, baffle element 64provide'd with vertical circular flange 71 and apertures 66,'and the connecting rods 68 are all shown herein." j
Referring now to Figure 5d, an alternate andpreferred element for preventing liquid entry into the vapor manifold is shown. Steel tube 6,2 is shown, as in Figure 3, adapted to be attached to vapor manifold 28 by means of threaded connection 60. vA normally closed llapper valve is employed consisting of stationary member 70 provided with opening 72 and llapper element 74. The stationary element may be fabricated of Ametal or of` the same or similar resilient material as the flapper element 74. For service with hydrocarbons, syntheticrubber such as neoprene and the like is used in the ilapper.
` Other `materials with thesequalications can be selected considering the properties of' theliquids being handled. v Thellapper741norn1ally closesopening 72 so that nolifquid can enter vapor manifold 28 from the compartment. Also of signicance is `the fact that the compartments are sealed from one another so that no vapor interchange can occurV betweenthern. This permits carriage of diiferentliquids in eachv compartment without danger of contamination. fWhen ,one `compartment discharges, the liquid levelY drops, forcing the displaced vapors through the vapor manifold` forcingfonly the appropriate frapper valve open, and'ilow into that same compartment.
,Referring particularly'to Figure 6 which shows another elementforrpreventing liquid ,entry into the vapor manifold, steel tube or nozzle 62 is-shown to be connected,
to a-synthetic rubber valve. The valve consists of tubular portion 63clarnp 65`and flattened portion 67. The
flattened portion is held normally closedby the resilience Y of the material Aof which it .is Vconstructed but opens for vapor Allow whenthe pressure in the compartment is less than that in the manifold system. i
The present invention has been described specically with respect `to therdelivery of volatile liquids from tank trucks and railroad cars and the like together with provision Afor recovering valuable or dangerous vapors displaced during liquid delivery. Itshould be understood,
as indicatedabove,Y that the sarne invention. may be Y employedi'n connection with the recovery of such vapors s they are evolved during the delivery of such liquids from tank trucks, trailers, railroad cars, tank ships, barges, and Yany other portable or moveable carrier for liquids, A
A particular embodiment of the present invention has been hereinabove described in considerable detail by way of illustration. It should be understood that various other modifications and adaptations thereof may be made by those skilled in this particular art without departing from the spirit and scope of the invention as set forth in the appended claims.k
We claim: Y
t1. An apparatus for dispensing a volatile liquid without vapor loss and atmospheric contamination, which comprises a movable delivery vessel, which vessel contains a plurality of individual compartments, a liquid receiving vessel, separate liquid inlet means communicating with each of said compartments, separate valve controlled liquid outlet means from the bottom of each of said compartments, said outlet means communicating with a conduit for liquid which in turn communicates with said liquid receiving vessel, thus permitting the ow of liquid from individual compartments of said delivery vessel to said receiving vessel, a conduit for vapor opening from the top of said receiving vessel and communicating with a vapor manifold conduit extending along the top of said delivery vessel adjacent each of said compartments, means connecting said vapor manifold conduit with the top of each of said individual compartments, said connecting means having means at their lower ends and located within each of said individual compartments for preventing entry of liquid from said compartments into said vapor manifold conduit and for preventing liquid flow between said individual compartments, and means for venting vapor from the closed system thus formed only upon generation therein of pressures in excess of a predetermined value.
2. An apparatus according to claim 1 wherein said means for preventing entry of liquid into said vapor manifold conduit and for preventing liquid ow between said compartments comprises a perforated plate dependent from said connecting means and disposed substantially horizontally in the top of each of said compartments and a substantially vertical circular flange extending upwardly from the outer edge of said plate.
3. An apparatus according to claim 1 wherein said means 'for preventing entry of liquid into said vapor manifold conduit and for preventing liquid flow between said compartments comprises a apper valve of resilient material dependent from said vconnecting means, said lapper valve being normally closed and adapted to be opened by the existence of a pressure in said compartment which is less than that on the other side of the apper valve disposed in that compartment.
4. An apparatus according to claim 1 wherein said means for preventing entry of liquid into said vapor manifold conduit and for preventing liquid flow between said compartments comprises a valve dependent from said connecting means, said valve being constructed essentially of resilient material and of tubular cross sec-Y tion at one end and attened atthe other, said valve being normally closed at the flattened end by the resiliency of the material and having a clamp means connecting the tubular end of said valve to said connecting means, said valve thus being adapted to be opened by the existence of a pressure in said compartment which is less than that on the other side of said valve.
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