US2696931A - Safety equipment for fuel tanks - Google Patents

Description

Dec. 14, 1954 T. D. WHIDDEN SAFETY EQUIPMENT FOR FUEL TANKS Filed Nov. 2, 1949 2 Sheets-Shut 1 FUEL TANK Oman I] FILTEA nu v imam rm;

' IN VEN TOR. TD W/i/OOEA/ BY A 4 e? ATTORNEY Dec. 14, 1954 T. D. WHIDDEN SAFETY EQUIPMENT FORFUEL TANKS Fill ed Nov. 2. 1949 2 Sheets-Sheet 2 4 INVENTOR. 72 0. Me /005v ATTOE/VE) United States Patent z",,'3i Y L Theron D. Whidden, Jacksonville, Fla. Application November:2,1949 Serial No; 125,140 8 Claims: c1-. 220 ss v This invention relates tosafety dev ices and moret-spe cifically to apparatusafor protectinga:'- tank-1:containing pump. This often allows the fuel to be siphoned-out of a broken line -and if this fuel becomes ignited, serious damage is caused. Moreover, in the case of wrecks or tipping'over of the equipment, many fires arecaused by fuel leakage from the present-ventsof the inverted tanks.

This dangeris so-well ..recognized tliat certainifire underwriters requirethat vents beyfitted-with a ball-type check valve whic h is supposed to-seator closeawhen thetank is; inverted, In many cases, these valves fail to function because of their infrequent use andbecause-they are more often than :not seriouslycorroded. .nEurthe'rmore, .rthere is-ant-additional hazard.-.tha't of -the .danger.-of the .tank explodingif theyado succeed in closing, because the tank has no means of relieving its internal pressure caused by'the expansion of the gases therein due to incre'ase' in temperature) ififire doescome incontact with the-tank; -While-thisdanger is recogriized,:.zi. very poor arrangement-hasibeen. offered "to' overcome this hazard, that is, an alloy rnet'al of low melting pointis employed in the head of the ball check and, this alloy'issupposed to melt and; relieve the pressure. Unfortunately, however, all: too -often. the fire menacing l theft'ank "is sufficiehtly remote from the'valvefso that.the .heat will not melt the seal quickly enough to prevent tank explosion resulting from the tremendously increased internal pressure.

It is, accordingly, another object of this invention to prevent, more'efficiently than it hasbeen accomplished in the past,-leakage of fuel from the vent in the eventof theequipment tipping over, or leakage of fuel from broken fuelflines between the tankand fuel pump.-

' Theabove and related objects are attained inaccordance withithe inventionby providing a novel expansion chamber arrangementemploying liquid type checkvalves and, in particular, using mercury asa valve seal. Moreover, there" is provided in combination with the expansion chamber and liquid type check valves a liquid carbon filter chamber as an improved means for conducting engine exhaust gases into the fuel tank for replacement of fuel when the latter is being used for engine consumption. The arrangement of the invention is of great importance because it is completely automatic in operation and requires no manual or mechanical valves, no pumps that require starting or servicing, or manual drains to open to discharge condensed water vapor while in transit.

The invention will be more readily understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which:

Fig. 1 shows in elevation a fuel tank and connected thereto a self-contained safety vent unit in accordance with the invention;

Fig. 2 shows the manner in which the self-contained Lit ice

. j 2 fif lyzifqt kun zQfxID Si WQEi H;i? seans ed pi-ane rr haust pipe throu for mjngpgrt rss s'sala arrangement i g." I Figs-4 o J. l i s ar sr i a tst .na -viaws of the safety-vent unitof this invention at various stages In Its p on, v is- @Referring more;speeifically;- to thedrawings, Hig 1 shows). yv y. of x mpl fo P po Qt llu ration, a self-containedsafetyyent unit 10 in accordance with the inv n n c ne e y mea st P s t-Iubg 110a u l. ta k lz crta tom t ve ql 'plt en a d. 1.. t-.- Qbviously,.the invention is not limited to the type of tank 12 tol-Whichthe unit; 1!) is conneeted, ..The}safety unit 10, which. will .be,described,-in detail below, is mountedljin the upr tpo t (sh w-m im 1.) an as s c rds .1 f ameahu hsad or w lls Th 1 sonnected betweenthe vent opening 13in the topofthefuel tank Hand to the fitting-14 on the safety device The unit 10 canbe mountedan'ywhere just so long as no portion of the, device 10 is lowerthan the bottom of the tank .12. v r

The device 10 comprises (.s'ee Fig. 4 as well as Fig 1), ',a pair of;cylindrical tanks, 15 and 16 which are joined togetherat top; and bottom to' form.a itopvpassage 17 and a, bottom passage 18.; In effect, tanksjlS, and, 16 form..a single chamber-19; into which the fuel in the tank 12 can expand, if the, temperature rises the fuel I passing through opening 14 into the expansion chamber 19 Also forming a part of the device 10 are othe flame guard or rr qrfi r 20 a d 21,...Wh canf e y ca in shape'and positioned below the tanks 15 and 16. The bottom ofchamber 20 isjconnected to the top passage11'7 of expansion chamber 19 by pipe 22 while thett'o'pfof chamber 21 is connected to. the passage117 by pipe 23. The upper part of cha mber 2 0 is connected to,.'an outlet pipe 24 while thetlow'erp ortion. of chamber 21 is connsste t an n tpipe lu nd Lr pw i y, can be usedto ,cap theo'pen ends ofLpip'es. 24 and 25. These plugs'or caps 26 and 27 are nof'intended to close outlet pipe 24 and inlet pipe 25 completely. These caps havesmall openings in theirheads ,to act as screens to prevent insects from entering thelpipes and causingst'oppage, The,.chambers.2ll and 21 are filled to substantially the levels'ZS and 29 shown inFig. 4, with a suitable'iioninflammablemliquid, such as gl'ycerine, which'v'vill readily with water but not withgas'oline. It 'also' has the viscosity ar d specificgravity required! A predetermined amount of mercury, such as one. fourth pound of mercury for eachone half poundl'lof'.glycerine,'for example, is placed in each chamber 20 and 2,1 and this'rnercurysinks into the pipes 22 an d 25 andrises therein as far'as the levels 30 and 31, respectively The chambers 20"and21 a'retheii sealed as by'replacing plugs (not shown) closing openings through which the glycerine and the mercury are poured), the fuel tank 12 is filled'and thefill cap 32 is screwed on tightl In' ord'er'to detect any leaks, the operator canblo w intoline' 25, with'the mouth or a small hand pump whilej soap suds are spread around all fittings. Air bubblesaround the fittings indicate leaks. Before describing the operation of the chambers 15,

.16, .;2 1 and their jassociated connections, referencewill first be made to Fig. 3 which-discloses a'ca'rbon filter chamber 40 in accordance with the invention and to Fig. 2 which shows such a filter chamber used with and forming a part of the safety equipment 10. The device 40 comprises a tank 41 having an upper portion 42 filled with steel wool or similar material 50 and a lower portion 43. In the lower portion 43 is a bell chamber 44 to which is connected pipe 45 from the exhaust pipe 46 of the vehicle carrying the fuel tank 12. The upper part of the tank 41 is connected by pipe 47 to the pipe 25. A filler plug 48 is provided in the side of the device 40 and a drain plug 49 in the bottom thereof. The chamber 41 is filled to the level of the filler plug 48 with glycerine or similar liquid. The carbon filter chamber 40 and the pipe line 45 become a condenser causing the water vapor in the exhaust pipe to condense and become water. This water and carbon particles from the exhaust become trapped in the lower part 43 of the filter, the gases rising to the surface of the device 40 and then through the line 25 when the mercury or liquid column becomes unbalanced (as will be pointed out more fully below in connection With Figs. 5 and 6) or when the liquid valve opens.

Reference will now be made to Pigs. 4 to 7, inclusive, which show various stages of operation of the device 10.

Fig. 4 shows the safety device 10 immediately after the attached gas tank 12 has been filled. The safety device is neutral, mercury and glycerine seals in chambers 2t and 21 and lines 22 and 25 are balanced. The tank is neither at a vacuum nor a pressure stage.

Fig. 5 shows the safety device 10 in a pressure or expansion state. Fuel in the tank 12 has changed temperature and is expanding. The liquid fuel passes through opening 14 into expansion chamber 19 which holds for example, approximately 11 pints of the expanded fuel. This expansion causes the air in the chamber 19 to be forced through openings 33 and 34 into passage 17 and overbalance the seal in chamber 20, allowing air to pass through the line 22 in small bubbles through the mercury and glycerine, going out through line 24 into the atmosphere. 7

Fig. 6 shows the safety device 10 in a vacuum or contraction stage which occurs when the fuel contracts or is drawn from the fuel tank 12, thus causing the seal in chamber 21 to become overbalanced allowing the air or inert gases to be drawn into line 25 and pass through the mercury and glycerine in small bubbles into line 23, through the openings 33 and 34 into chamber 19 and down through opening 14 into the fuel tank 12.

Fig. 7 shows the safety device with the carbon filter chamber 40 attached and using inert gases from the engine exhaust 46 as shown in Figs. 2 and 3. Chamber 19 becomes a reservoir for inert gases to supply the fuel tank 12 whenever there is a decrease of temperature and the engine is not in operation. The filter chamber 40 automatically expels any excess water out the lines 45 and 46. Since the flow of gas is periodic due to opening and closing of the liquid valves, any excess Water will rise higher in chamber 42 during inhaling and this height or weight of liquid will force itself into bell chamber 44 and out line 45 to the exhaust pipe 46 as soon as inlet flow is interrupted. The bell chamber 44 is arranged to prevent the natural expansion of gases from forcing all of the liquid out line 45 as, when expansion forces all of the liquid out of chamber 42, the bell chamber 44 is still full and air or gas will pass through this liquid and escape out line 45. Now in the reverse operation, the inlet flow of exhaust gas forces all of the liquid out of the bell chamber 44 into chamber 42 allowing the passage of air or gas upward through the liquid, thus washing the gas'and depositing carbon, which settles below bell chamber 44. This chamber also is a flame and spark arrestor, thus assisting the chambers 22 and 25. The metal or fiber wool 50 in chamber 42 serves to collect the splash of liquid and allow it to drain off below and also to condense water vapor in gases and for further collection of fine carbon compounds in the gases.

It will be evident that there has been described above an expansion chamber 19 which offers a space for expansion of fuel and splash of fuel from the tank 12, that retains this splash and expansion and that cannot be filled by human carelessness; furthermore, it offers both inhaling and exhaling means and also affords means for returning the splash, expansion and condensation of vapors to the fuel tank 12, assists in the entrapment of fuel in case the vehicle tips over and offers a reservoir for non-combustible gases. A multiplicity of other advantages will be apparent to those skilled in the art.

While the present invention has been described in terms of a preferred illustrative embodiment, it will be realized that the invention and its several features are susceptible of embodiment in a Wide variety of other forms and hence the invention is to be understood as comprehending such other forms as may fairly come within the spirit and letter of the claims.

What is claimed is:

1. A safety vent unit for a fuel tank comprising an expansion chamber separated from the tank and adapted to be connected to the upper part thereof, said expansion chamber comprising a pair of vertically-disposed cylindrical tanks having passageways therebetween at the top and bottom thereof, means for connecting the bottom passageway to said fuel tank, a pair of flame arrestor chambers located under said cylindrical tanks, respectively, a pair of tubes for connecting said top passageway respectively to the under portion of one of said flame arrestor chambers and to the upper portion of the other, and respective connections from said two flame arrestor chlarrfibers to the atmosphere for pressure and vacuum re 1e 2. The combination of elements as in claim 1 with a layer of mercury in each of said flame arrestor chambers.

3. The combination of elements as in claim 1 with layers of mercury and of another liquid in each of said flame arrestor chambers.

4. The combination of elements as in claim 1 with layers of mercury and of glycerine in each of said flame arrestor chambers.

5. The combination-of elements as in claim 1 with a carbon filter chamber connected between one of said respective connections and a source of inert gas containing carbon particles to be removed.

6. A safety vent unit for a fuel tank comprising an expansion chamber separated from the tank, said chamber being normally free of liquid and adapted to have its lower portion connected to the upper portion of said tank, liquid pressure relief and vacuum relief chambers adjacent said expansion chamber and each relief chamber having a mercury column therein, means connecting the top of said expansion chamber through the mercury column in the liquid pressure relief chamber to the atmosphere, and means connecting the top of said expansion chamber through the mercury column in the liquid vacuum relief chamber for entrance of air or other gases.

7. The combination of elements as in claim 6 in further combination with a layer of a liquid other than mercury in each relief chamber to prevent mercury splatter.

8. The combination of elements as in claim 6 in further combination with a layer of glycerine in each relief chamber to prevent mercury splatter.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,671,492 Skinner May 29, 1928 1,693,430 Austin Nov. 27, 1928 1,929,462 Woidich Oct. 10, 1933 1,949,212 Lowther Feb. 27, 1934 2,153,555 Gallery Apr. 11, 1939 2,375,834 Walker May 15, 1945

Images