WO1994000348A1

WO1994000348A1 - Underground construction for aircraft fuel storage tanks

Info

Publication number: WO1994000348A1
Application number: PCT/IT1993/000062
Authority: WO
Inventors: Gaetano Cutore
Original assignee: Gaetano Cutore
Priority date: 1992-06-23
Filing date: 1993-06-22
Publication date: 1994-01-06
Also published as: ITRM920482A1; ITRM920482A0; IT1254405B

Abstract

An underground construction for receiving buried hydraulic assemblies to be used for refuelling in general vehicles and in particular aircrafts, above all military aircrafts, such hydraulic assemblies being self-contained units formed of a retractable delivery station (CE) which is supplied by two fuel tanks (SR1, SR2) connected thereto, consists of: an outer carrying frame (10) of rectangular form which is laid down at the surface level with respect to the hole for the buried tanks, surrounds the opening of such hole, supports the delivery station and the tanks both by supporting their weight and by withstanding the upwards thrust due to the buoyancy in case the hole is flooded, and is made of reinforced concrete; and a number of covering flat blocks (15) also of reinforced concrete, such frame being provided with a central panel having an octagonal opening (21) which receives the delivery station, a number of anchoring means for the beams (14) supporting the tanks, and stepped portions for receiving the heads of the covering flat blocks.

Description

UNDERGROUND CONSTRUCTION FOR AIRCRAFT FUEL STORAGE TANKS

The present invention relates to a construction for receiving buried hydraulic tanks. Such construction is especially. but not exclusively, intended to receive hydraulic tanks to be used for refuelling in general vehicles and in particular aircrafts, above all military aircrafts .

The hydraulic tanks of the above-mentioned type are self- contained units formed of a delivery station supplied from two fuel tanks connected thereto. Both the delivery station, which is of the retractable type, and the connection system to the tanks are objects of preceding Patent Application of the same Applicant. The construction according to the invention is formed of

SUBSTITUTE SHEET an outer carrier assembly surrounding at the surface le¬ vel the mouth of the digging for burying the tanks, and supporting the delivery station and the tanks both by carrying their weight and by withstanding the upward thrust due to the buoyancy in the hole (principle of Ar¬ chimedes) in case the latter is flooded.

The outer carrier assembly is formed of a rectangular frame of reinforced concrete and a set of covering flat blocks also of reinforced concrete. The frame is provided with a central panel having an octagonal opening, in which the delivery stat±βn is received, and a set of beam attachements for the beams supporting the tanks, and stepped portions for receiving the heads of the flat blocks. Transversal beams, preferably of the double T type, sup¬ porting the tanks by means of slings are connected to such frame. The heads of the beams are sandwiched between a steel plate integral with the side members of the frame and a bearing plate by means of threaded rods crossing the flanges of the beams and the plates, and nuts welded to the latter.

The construction according to the invention allows the digging which receives the hydraulinc subassemblies to be excavated under safety conditions. In fact the ground will be first dug so as to form a hole having the same form, length, width, and depth as the outer frame which is then cast into concrete casting moulds containing the metal reinforcements, whereupon the ground will be further dug inside and underneath such frame. Once the digging is completed, the tanks are introduced therein and then the transversal beams are connected to the outer frame as mentioned above.

SUBSTI It should be noted that the tanks can be filled up with water so that they can be sunk if there is water in the digged hole .

The two tanks will then be secured to the respective overhanging beams so that they are suspended thereto, whereupon the self-contained delivery station encased in an outer envelope shaped as an octagonal truncated prism is lowered into the octagonal opening of the main panel. It should be appreciated from the foregoing description that this invention provides a surface construction of rectangular shape made of reinforced concrete, to hich buried tanks and a delivery station can be attachec hus avoiding any reinforced concrete bed at the bottom of holes which are some meter deep and often flooded with stratum water or rain water both during the installation and the following steps, and further avoiding danger for the personnel working at the bottom of the holes and attaching the tanks to the bed. The surface construction can withstand any buoyancy of the empty tanks and the delivery station, since it can be easily given a whole weight higher than the maximum hy¬ drostatic thrust (about 100.000 kg of two tanks each of

3 50 m ) . This construction allows also support poles to be used only in case of extremely soft ground. Moreover, the deep digging (about 4 meters), in which the tanks and the delivery station should be quickly installed by sinking them as a result of their possible filling up with water, should be made only after the setting of the surface construction of reinforced con- crete and possibly when tanks and delivery station are ready to be buried. It, should be noted that it is convenient to fill the rooms between tanks and walls of the digging with wet sand in order to avoid any landslip.

The delivery station will be easily introduced into the opening of the panel of corresponding shape and connected to the tanks by coupling its plane faces to the corre¬ sponding plane faces of the flanged manhole necks of the tanks.

The construction makes also it possible to remove the delivery station from its casing and to transfer it to another place; this is carried out after loosening the fastening bolts connectxng the casing of the delivery station to the manholes of the tanks and by lifting then the station by means of a crane. The construction allows the whole area of installation to be practicable and capable to bear loads of trucks by means of a number of flat blocks of reinforced concrete having suitable size to be laid down between the two long opposite sides of the rectangular frame forming the sur¬ face construction; the reinforcement and the flat blocks are such as to bear the loads of the surface trafic without damaging the tanks.

The two buried tanks can be removed from the hole by moving away the flat blocks, removing the overlying sand, disassembling and moving away the transverse beams, and removing the tanks from the digging by means of a crane.

The invention will now be described in greater detail with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal section of the construction in situ;

Fig. 2 is a cross-section taken along line II-II of Fig.

^{1 :} SUBSTITUTESHEET Fig. 3 is a perspective top view with sectioned portions and broken away portions; Fig. 4 is a top plan view;

Fig. 5 is a perspective, fragmentary, detailled view showing the connection of the transverse beams to the side members of the frame of the construction; and Fig. 6 shows the cross-section of a flat block.

With reference to Figs. 1 to 3 the construction according to the invention is generally formed of an outer frame 10 of reinforced concrete having two long sides 11, two short sides 12, a central panel or platform 13, six tran¬ sverse beams 14 and a number of transverse flat blocks

15- The upper face of long sides 11 and transversal sides 12 of surface frame 10 is formed with a step, as indicated at 16, on which the heads of flat blocks 15 rest. Fur¬ thermore, three cavities or grooves 18 (Fig. 5) evenly spaced at either side of the central platform ar formed in each longitudinal member 11 of frame 10, a ι,-shaped plate 19 being inserted in each groove and anchored to the body of such member by brackets 20 for the purpose discussed thereafter. Moreover, an octagonal opening 21 is formed in the cen- tral panel or platform 13 which, as already mentioned, is intended to receive the delivery station CE (Fig. l) which is shown in solid lines when it is within the con¬ struction and in dashed^Jines when it is lowered to its position into the opening. Proλ'ided at the opposite plane surfaces PF of delivery station CT. are flanges FL which are bolted to corre¬ sponding flanges LF of the "goosenecks" or manholes PL^*

SUBSTITUTE SHEET which connect tanks SRI and SR2 to the body CR of the station.

As can be easily understood, goosenecks PU have con¬ necting collars to be cut to measure in order to fit the distance between tanks and delivery station so that the connecting flanges of the goosenecks correspond to those of the delivery station.

Tanks SR are hung to the double T beams 14 by means of slings 23, and beams 14 have,, as already mentioned, ends 24 connected to plates 19 anchored to the longitudinal members 11 by a bearing plate 25, two threaded rods 26 crossing both the two plates and the flanges of beams 14, and nuts 27- When introduced into opening 21, delivery station CE in turn is held in position by projecting tabs 28 which are bolted to the edges of said opening.

Once tanks SR are hung to beams 14 by slings 23, and goosenecks or manholes PU cut to measure and connected by per se known collars are bolted to delivery station CE held in position by its flanges, and the hole is filled up with bedding sand, the covering flat blocks 15 are placed on the frame at either side of central panel or platform 13, the ends of such blocks being flush with step 16. It should be appreciated that flat blocks 15 of rein¬ forced concrete have a stout inner reinforcement, as shown in Fig. 6, which allows any even very heavy vehicle to roll on the construction. Of course, the tanks are not only connected to the deli- very station through manholes PU allowing the tanks to be easily reached for inspection, maintenance and cleaning, but also to the fuel delivery pipes and cables for cen- TITUTESHEET tral units .

As already mentioned, the delivery station is of the re¬ tractable type, which is the object of a preceding Patent Application of the same Applicant. It should be noted that such station is moving between a rest position, in which it is completely received in the octagonal body and its upper portion, i.e. a stout steel plate, is flush with panel 13 and flat blocks 15, and an operative posi¬ tion, in which it projects to a certain extent for al- lowing its control means to be connected thereto.

SUBSTITUTE SHEET

Claims

1. A construction intended to receive hydraulic assem¬ blies buried in the ground and manufactured as self- contained units for refuelling vehicles, in particular aircrafts, which are formed of a retractable delivery station moving between a rest position, in which it is completely concelead with its upper portion being flush with the surface of the construction, and an operative position, in which it projects from said surface, wherein it includes an anchoring and supporting frame (10) of reinforced concrete having two long sides (11), two short sides (12), a central panel or platform (13) provided with an octagonal opening (21), several transversal beams (14) anchored to the latter, and a number of transversal covering flat blocks (15). said refuelling unit or tank (SR) being hung to said transversal beams (14) and said delivery station (CE) being of octagonal shape with di¬ mensions corresponding to those of said opening (21) so that it can be introduced therein and received into the ground.

2. The construction of claim 1. wherein said long sides (11) of said frame have several opposite grooves (lS) in each of them a stout L-shaped plate (19) is received and anchored. the heads of said beams received in said grooves (l8) being tightened to said sides between each L-shaped plate (19) and a corresponding bearing plate (25) by threaded rods (26) and nuts (27). said tank (SR) being hung to said beams (14) by slings (23) of the known type so that said beams can withstand both the weight and anv thrust or buovancv in case the hole is flooded.