CA2535657A1 - Portable double-walled fuel tank - Google Patents

Abstract

A double-walled tank for the transport of fluid, the tank includes a rigid fluid impervious substantially cylindrical inner container concentrically nested within a rigid correspondingly substantially cylindrical outer container, the inner and out er containers having end walls sealing the containers. A grapple mount is mounted to an upper side of an outer surface of the outer container at a substantially metal position substantially medially along the outer container. A lower side of the outer container, opposite the upper side, is reinforced. The grapple mount may include a rigid plate mounted atop the upper side of the outer container at the medial position. An anti-surge baffle is mounted across, so as to extend between an d into engagement with, an upper side of the inner container adjacent the baffle mount and a lower side of the inner container adjacent the reinforced lower side of the outer container.

Description

PORTABLE DOUBLE-WALLED FUEL TANK
Field o tlie Invention This invention relates to a double-walled fuel tank, which is constucted so as to be readily t,ransporkable over rough terrain to a remote timber-harvestiztg site oz't'e-locata.ble on such a site by log handling equipment such as, for example, a grapple machine.

Backgound of the Invention Titnber harvesting is getter,ally carried out at sites which are Witzally remote and accessible only by very rough sIci.d roads. Harvesting equipment such as feller-bunchers and grapple skiddexs arE utilized in transporting cut logs and whole trees from even more remote and inaccessible locations to the skid roads. Such harvesting equipment, by way of example, and other equipment used generally in this timber-harvesting environment, need to be supplied with an adequate supply of fuel for their contbinuous and efficxent operation.

Presently, small quantities of fuel are carried in tanks of limited fuel capacity by foux-wb.eel-drive trucks or the like to a remote timber-harvesting site. Even the transportation of these small quantities of fuel by this method requires that a fairly smooth roadway be provided, generally free of felled timber, logging debris and excessive gradients.

Of furfher concern is the iaeed to relocate the fuel within a cutting site to keep it in general proximity to the hw"vesting equipment as it works through a har.
vestiug area. Generally, the cutting and harvesting of timber and the movement of associated equipzn ent will produce a tetxaiz) unsui.table for travel by any vehicle other tha.n articulated, high ground clearauce grapple skidders or the like.

There is a need under such timber harvesting conditions to provide a fuel tank of sufficient fuel capacity and manufactured with the strength and durabiUty to be transported by a grapple machine or the like to and around a remote timber=-b,arvesting site.
Such a fuel tank, therefore, will provide all ancillary equipment necessary for pumping the fuel from the tank to the timber harvesting equipment as well as safety equipment necessary for suppression of accidental fire.

Sunatxtarv of the Itrventiotx The double-walled fuel tank of the present invention may be manufactured froxn 1/$-inch thick tni ld steel and comprise an inner cylindrical fuel-eontaining receptacle or tank and an outer cylindrical protective sheath.

The inner fuel-receptacle is concentrically uested within the protective outer sheath by means of a plurality of radially outwardly extending spacers, for example mild steel spacers, extendiztg between the outer surface of the fuel tank and the inner surface of the protective outer sheath. End spacelrs exten.d fore and aft of the respective end walls of the iw.tter fuel tank and are suitably aperturetl at intervals along their length to pemit liquid to drain by gravity to the lower portiob of the outer sheath. The outer sheath has fore and aft end walls monnted to the end spacers so as to be spsced outwardly from the respective end walls of the inner fuel tank.

Outer sheath may bave a bulkl)ead spaced forwardly from its aft end wall to provide a storage eompartmcnt for retaining such equipment as battezies, an electrical motor, fuel boses, fire suppressi.on equipment and the like which are readily accessible through an access hatch provided in the aft end wall. The stoz-age compartment maybe secured by a door, hinged at an end to the aft end wall of the outer sheath and which may be supported in an open position by gas sltocks or the like. The bulkhead wall of the outer sheath tnay be mounted to the respective ends

2 of the oorresponding end spacers on the fuel tank. A draiux plug is provided in the aft end wall to allow drainun-g of liquid from the storage conipartmeztk.

Axiaily aligned separate fuel filler pipes are provided on the upper surface of both the inner f.uei tank outer protative sheath near the aft end of the fuel tank.
Similarly, axially a.ligned drainage plugs are provided in the respective lower sttifaces of the fuel tank and the protective outer sheath.

The inner fuel tank may have an intezpal anti-surge baftle mounted medially of the fore and aft ends of the receptacle, which inhibits imbalance due to fluid movement during transportation.

A fuel sliut-off valve passes through both the aft end of the fuel-containin.g receptacle and the storage compartment bulkhead. Such valve is normally closed and is opened wben eurrent from the battery power is connected to operate a fuci pump to discharge fuel to the timber harvesting equipment.

The double-walled fuel ta* has fore and aft supporting skids, an eacterior, lower reinforcement collar positioned m.ediaily of its ends, an upper grapple platform and fore and auH:
grapple positioning brackets located in proximity to the upper grapple piatforrn.

Gussets affLxed between the fore end tank supporting skid and outer sheath are apertured to peamxt attachment of chains or the like which may be secured to the body of a transporting mechanism such as a grapple machine to restrict yaw of the tank dtu'ixtg transport. In addition, loops manufactured from a chain link or the like may be provided at each of the grapple positioning braciCets to afford a safety chain comtection point between the tank and suitable attachrnent points located on the grapple jaws.

3 The portable double-walled fael tank in accordance with one embodiment of the invention may be generally cbaracterized as including:

(a) an outer, ge,xa.arally horizontally disposed cylin.drical sheath, wbich comprises the outer protective wall of the fuel tank, manufactured, by way of example, from 1/8 inch tbick mild steel or the like material with fore and, aft end wails which define an internal cavity.
(b) An internal bulkhead positioned forwardly from the aft end wall of the outer sheath which defines a smaller cavity or. storage compartment, wherein external access is provided, to the storage coznpartmeztt through a securable door or access batch provided in the aft end wall of the sheath.
(c) Fore and aft slcids secured beneath the outer cylindrical sheath support it in an elevated aspect relative to the ground surface. ' (d) A lower reinfarcemeztt collar, generally surrounding the lower segment of the outer sheath, intermediate its ends, extends ganera[ly upwardly to the mid line.
(e) A grapple platform and fore and aft grapple positioning brackets are located on the upper side of the cylindrical shea.tb..
(f) An inuner fuel xeceptacle concezt.trically nested within the protective outer sb.eath by means of a plurality of radially outwardly extending mild steel spacers extending betwee , the outer sux%ce of the fuel containing receptacle and the inner surface of the protective outer sheath. The spacers geaerally extend fore and aft of the inner fuel receptacle.
(g) An iuntemah anti-surge baffle is provided medially of the fore and aft ends of the fuel-receptacle to structurally reinforce the tank where it is gripped by a grapple while being carried, the baffle having uppez and lower aperlures or cut-outs which ix-.lubit surging, for example due to a pressure differential on extber side of the baffle, and which allows substantially unrestricted flaw of liquid during pumping of liquid from the tank.

4 tn summary, the pTesent invention may be characterized in one aspect as a double-walled tank for the transport of fluid, the tank including a rigid fluid impervious substantiall.y cylindrical inner container concentrically nested witkxin a rigid correspondiztgJ.y substantially cylindrical outer container, the inner and outer containers having end walls sealing the containers.
A grapple mount is mounted to an upper side of an outer surface of the outer container at a substantially medial position substantially medially aloixg the outer container. A lower side of the outer contaiaer, opposite the upper side, is reizaforced. The grapple mount may include a rigid plate mounted atop the upper side of the outcr container at the medial position.

An anti-surge baffle is mounted across, so as to extend between and into engagement witIh, an upper side of the inner container adjacent the baffle mount and a lowe.r side of the inner container adjacent the reinforced lower side of the outer container. The baffle has an upper aperture in an upper side of the baffle adjacent the upper side of the inner container. The baffle has a lower aperture in a lower side of the baff]e adjacent the lower side of the inner container. The lower aperture is defined between lower extremities of the baffle mounted to the lower side of the inner container. The lower extremities of the bafde extend along iui supporting contact with an inner su.rface of the lower side of the inner container so as to be coextensive with distal ends of grapple arms of a$rapple engaging the grapple mount so as to extend the grapplc arms of the grapple around a grapple line extending substantially from the substantially medial position and extending around the outer container from the upper side to the lower side of the outer container.

A radially spaced apart array of rigid stringers extend along the inner and outer containers in a sttbstaAtially cylindrical gap between the inmer and outer containers. The array of rigid st;ringers are mounted to, so as to extend between, into engagement with, the inner and outer containers so as to rigidly space apart the inner and outer containers. At least one stringer of the array of rigid stringers is sandwiched ozk opposite lateral sides of the inner and outer containers betwecn the inner container and the reinforced lower sidc of the outer container.

5 in one embodiment the end walls are single-walled end walls providing a common end wall on each end of the inner and outer containers, and the rexo,forced lower side of the outer container includes a rigid .reinforciza.g collar mounted to and around the lower side of the outer container. Advantageously the reinforcing collar extends partdally along the length of the outer container so as distribute compression loads from the grapple axxns along the striatgers sandwicbed between the inner container and the lower side of the outer container.

The baffle may be a rigid circular plate baving a first cutout at an upper end thereof forming the upper aperture, and having a second cutout at a lower end thereof forming tb.e lower aperture. The first and second cutouts may in one ezztbodinaent be substantially semi-circular. and synzmetrical about a vertical plane bisecting the inner and outer containers.
The second cutout advantageously may be larger in cutout area thaxk the first cutout. For example, the second cutout may extend substantially one quarter of the veztical inside diameter of the innar container. The first cutout may be an air passage. The second cutout may be a fluid passage in fluid communication between opposite ends of the inner contaixier tin corresponding opposite sid.es of tbe baffle.

The array of rigid stringers may include eight elongate rigid mcmbers in radially spaced apart array about a lonotadinall.y extending substantially centroidal axis through the inner and outer containers. The radially spaced aparC array of stringe;rs may be substantially equally radially spaced apart, and five of the eight rigid members may be sandwiched between the lower side of the inner container and the reinforced lower side of the outer container.

Brief Descrinti.on of the Dirawinss Figure 1, is a perspective view of the fue! tank being transported by a grapple machine.

6 Figure 2 is a perspective view of the fia,el tank Figure 3 is a. sectional view taken on line 2-2 of Figure 1, with the iianer tank partially broken away for clarity.

Figure 4 is an ezilarged sectional view taken on line 3-3 o.f. b'igure 1.
Figure 5 is an enlarged view of the gussets at the forward end of the tank' Figure 6 is an enlarged vAew of grapple positioning bracket.
b'igare 7 is an enlarged view of a portion of Figure 2.

Detailed Deacrintion of Embodiments of the Invention With reference to the dr.awing figures, wherein similar characters of reference denote corresponding parts in each view, the fuel tank 10 of the present invention genera.lly comprises a horizontally disposed outer cylindrical sheath 12 havxng fore and aft ends 14 and 16 respectively which define an internal cavity 20. Bulkhead 24 is positioned forwardly fxom aft md wall 16 of outer sheath 12 tlaereby defining a storage compartment 26. A
securable door 30 or access hatch is provided in aft end wall 16. Door 30 is hinged at one end such as at 32 and has closure means such as basp 34 at the opposite cnd. Lug 34a positioned on aft end wall 16 engages hasp 34 to effect secure closure. Door 30 may be supported in an open position by means of gas shocks 38 suitably secured between, door 30 and aft end wall 16. A removable drain plug 42 is provided so that storage compaz'tment 26 may be kept ffree from naoisture or accidentally spilled fuel. A protective outer tank filler pipe 44 and cap 44a are provided adjacent builcbead 68.

7 Fore and aft skids 46 and 46a respectively are seeured beneath outer cylindrical sheath 12 as by welding or the like and support it in an elevated aspect relative to the ground surfiLce.

A lower rexuforcement collar 50, is positioned $erterallyitttermediate ends l.4 and 16 of sheath 12 and surrounds the lower segment of outer sheath 12, extending generally upwardly to mid line bisecting sheath 12 along its length.

A grapple platform 52 and fore and aft grapple positioning bra.ckets 54 and 54a respectively are locatcd on. the upper side of cylindrical sileath 12, intermediate its end and are used by a grapple machine operator for the proper placement of the liftiztg grapple 56 as may be viewed in Figure 1. Brackets 54 may have we)ded thereto a link o~4-inch chain 58 or the like to accommodate a safbty chain attached to the grapple 56.

An ;imer fuel receptacle or tank 66 is nested concentrically within outer, sheath 12 by a radiaJly spaced apart array of longitudinally extending stringers or spacers 68 radially spaced for example on radial lines C. Tank 66 may be manufactured fiom 1/8 inch mild steel material and spacers 68 may be manufactured from one half inch naild steel matexial or the like. Spacers 68 generally contain spaced apart drainage apertutes 70 along their length so that any moisture aceumulatirig between exterior cylindrical sheath 12 and inz-er fuel-receptaeie66 may be drained by gravity through drainage apertures 70 so aõa to be drained from sheath 12 through plug 74. A
separate drainage plug 78 is provided for inner fuel receptacle 66. Plug 78 is preferably axially aligned with drainage plug 74 in outer sheath 12. The spacers generally extend fore and afl of the respective end walis 82 and 84 of inner fuea, receptacle 66 so that a protective void surrounds inner tank 66.

An internal anti-surge baffle 86 is provided medially of the fore and aft ends of the fuel-receptacle 66, which reduces dynamic imbalance due to fluid rn.overnent during

8 transportation_ An upper cutout 86a eliminates any pressure differential occuriring on either side of the baffle as fuel is pum.ped from receptacle 66 while lower cutout 86b allows unrestricted flow of liquid during pumping from the tauk. Cutouts 86a and 86b also reduce the weight of the baffle while leaving the structvxal reinforcement provided by the baffle around the grapple line B, that is, where grapple 56 grips sheath 12.

A fuel shut-offvaIve 88 passes through both the aft end 84 of the fuel-containin.g receptacle 66 and the storage compartment bulkhead 24. Valve 88 is n.omally closed and is opened wben current from battery power associated with fuel pump operation is actuated.
Gussets 92 welded to skid 46 near the fore end of the tank contain apertures whicla permit connection of a chain 100 which is passed upwardiy and around thc tank and crossed over the tank attd oortnected to the skidder on opposite sides of the tank to increase tak stability during transportation over uneven ground.
i5 Spacers 68, because they are rigid stringers running the length of the gap between tank 66 and sheath 12, stremgthen tlxe structuures and thereby allow the use of lighter material in the wa.lls. For example, the walls of the tank and sheath may be of one eightb.
inch thick mild steel, replacing a previous single walled desigt2, employing walls having a thickness of one quarter inch mild steel. The weight added over the previous design includes the weight due to the weigbt of the stringers 68, reinforcemeut collaY 50 and baffle 86. The stucture tbus not only provides the increased safety of a double-walled design, that is inadvertent puncturing of the outer wall does not necessarily also breach the inner wall, but also provides both increased structura3 strength in the mid,area in, proximity to grapple line B where clamping forces D are applied by grapple 56, but also provides for control of surging from eAd to end of fuel within the ta k 66. The stringers (spacers 68) and wide surfaced rigid collar 50 distxabute the forces applied by the grapplc arms of grapple 56 and transfer the forces into the plane of baffle 86, even if the grapple acros are not exactly co-planar with the baf.fle duc to slippage ofthe grapple or rr.xig-alignr.nent by the opera.tor.

9 in particular the lower ends 86c extend downwardly so as to be adjacent the cnds of the grapple arms of grapple 56 so that all of the compression forces from the grapple are transferred to the web, that is, the contiguous solid structure of the bafflc.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of tbhis invention without departing from the spirit or scope tbereof. Accordingly, the scope ofthe invention is to be construed in accordance with the subsmnce de5ned by the following claims.

Claims (12)

WHAT IS CLAIMED IS:

1. A double-walled tank for the transport of fluid comprising:

a rigid fluid impervious substantially cylindrical inner container concentrically nested within a rigid correspondingly substantially cylindrical outer container, said inner and outer containers having end walls sealing said containers, a grapple mount mounted to an upper side of an outer surface of said outer container at a substantially medial position substantially medially along said outer container, a reinforced lower side of said outer container opposite said upper side, an anti-surge baffle mounted across, so as to extend between and into engagement with, an upper side of said inner container adjacent said baffle mount and a lower side of said inner container adjacent said reinforced lower side of said outer container, wherein said baffle has an upper aperture in an upper side of said baffle adjacent said upper side of said inner container, and wherein said baffle has a lower aperture in a lower side of said baffle adjacent said lower side of said inner container, said lower aperture defined between lower extremities of said baffle mounted to said lower side of said inner container, wherein said lower extremities extend along in supporting contact with an inner surface of said lower side of said inner container so as to be coextensive with distal ends of grapple arms of a grapple engaging said grapple mount so as to extend the grapple arms of the grapple around a grapple line extending substantially from said substantially medial position and extending around said outer container from said upperside to said lower side of said outer container, a radially spaced apart array of rigid stringers extending along said inner and outer containers in a substantially cylindrical gap between said inner and outer containers, said array of rigid stringers mounted to, so as to extend between, into engagement with, said inner and outer containers so as to rigidly space apart said inner and outer containers, at least one stringer of said array of rigid stringers sandwiched on opposite lateral sides of said inner and outer containers between said inner container and said reinforced lower side of said outer container.

2. The device of claim 1 wherein said end walls arc single-walled end walls providing a common end wall on each end of said inner and outer containers.

3. The device of claim 1 wherein said reinforced lower side of said outer container includes a rigid reinforcing collar mounted to and around said lower side of said outer container.

4. The device of claim 3 wherein said reinforcing collar extends partially along the length of said outer container so as distribute compression loads from the grapple arms along said stringers sandwiched between said inner container and said lower side of said outer container.

5. The device of claim 4 wherein said grapple mount includes a rigid plate mounted atop said upper side of said outer container at said medial position.

6. The device of claim 1 wherein said baffle is a rigid circular plate having a first cutout at an upper end thereof forming said upper aperture, and having a second cutout at a lower end thereof forming said lower aperture.

7. The device of claim 6 wherein said first and second cutouts are substantially semi-circular and symmetrical about a vertical plane bisecting said inner and outer containers.

8. The device of claim 6 wherein said second cutout is larger in cutout area than said first cutout.

9. The device of claim 8 wherein said second cutout extends substantially 1/4 of the vertical diameter of said inner container.

10. The device of claim 8 wherein said first cutout is an air passage and wherein said second cutout is a fluid passage in fluid communication between opposite ends of said inner container on corresponding opposite sides of said baffle.

11. The device of claim 1 wherein said array of rigid stringens includes eight elongate rigid members in radially spaced apart array about a longitudinally extending substantially centroidal axis through said inner and outer containers.

12, The device of claim 11 wherein said radially spaced apart array are substantially equally radially spaced apart and wherein five of said eight rigid members are sandwiched between said lower side of said inner container and said reinforced lower side of said outer container.