US2765151A - Suction box - Google Patents

Description

J. LAMB SUCTION BOX ocpz, 1956 Filed Sept. '9, 1953 Fleuzs t HeuRE4 lnven ror JOHN LAMB EL, y. 777%: His A++orne9 FIGURE 2 SUCTION BOX John Lamb, London, England, assignor to Shell Development Company, Erneryviile, Calif., a corporation of Delaware Application September 9, 1953, Serial No. 379,254

Claims priority, application Great Britain November 18, 1952 6 Claims. (Cl. 257-198) The present invention relates to suction boxes such as are used in the evacuation of liquids from storage tanks and the like, the suction box being fitted to the lower end of a pipe leading from the tank to the pumping equipment by means of which the contents of the tank are removed.

In order to allow as much as possible of the liquid to be withdrawn from the tank the suction box is usually supported with its apertured base just above, for example about /4 inch above, the bottom of the tank. For a suction box to function satisfactorily in such a position, however, the box needs to be of such dimensions that the total length of the boundary wall defining the base aperture of the box is considerably greater than the circumference of the pipe through which the liquid is removed from the tank in order that evacuation of the tank should proceed efiiciently under these conditions.

The present invention is concerned with an improved suction box which can be used for the discharge of a wide variety of liquids, including fuel oil from storage tanks, for instance, in oil tankers. With viscous liquids pumping becomes a greater problem, and hitherto it has been the practice to encircle the suction box with a coil of piping through which steam or other heat supply can be passed. Such a coil, however, interferes with cleaning operations, and with periodic inspection work; also corrosion rapidly develops since steel tubes must of necessity be used for a heating coil of this nature. External heating of the suction box is, moreover, of limited value in maintaining the viscosity of liquid inside the box and connecting pipeline at a suitably low value and a need exists for a suction box which is effective for the discharge of liquids of widely different viscosities.

The present invention comprises a suction box for evacuating liquids from storage tanks wherein the inlet aperture is defined in part by a wall or walls having an aggregate length not less than six times the width of the widest portion of said box and provides an effective suction area as hereinafter defined greater than the area of the outlet aperture and wherein the suction cavity is traversed by one or more passages for the transmission of heat.

The expression effective suction area as used herein is intended to signify the area of the inlet aperture of the suction box which is e'n'ective for suction purposes when the box is supported with the upper edge of its inlet aperture inch removed from the base of a flat bottomed liquid storage tank.

Preferably the inlet aperture of the suction box is defined by the peripheral wall of the said box and by the wall or walls of one or more channels of ample cross sectional area traversing the base of the said box between the peripheral walls and opening into the said peripheral wall at the ends of the channels to be supplied with liquid.

The passages for the transmission of heat are preferably tubes adapted for the circulation of a heating fluid, although heat in other forms, e. g., an electrical resist- 'ice ance heating element, may be mounted therein. The tubular heating passages are advantageously located immediately above the said inlet channels so as to transmit heat to the entering liquid; alternatively, the tubular heating passages are located within the said inlet channels.

The suction box conveniently comprises a casting wherein the said heating tubes are integral with the box and extend entirely through the box, the open ends there being coupled to one another outside the periphery of the box to form a single circuit for the transmission of a heating medium directly through the tubes and couplers. Alternatively, the suction box may comprise a casting wherein the said integral tubes serve merely as structural supports to carry tubular members or pipes that are coupled to one another to form a single circuit for the transmission of a heating medium.

The tubes or tubular members for the transmission of heat are provided with suitable couplers for connection to a source and sink, respectively, for the heating medium; when the tank is equipped with a grid of heating pipes for heating liquids stored in the tank, the suction box is advantageously disposed to facilitate connection of the said couplers to include the said tubes or tubular members parts of the said grid.

A suction box in accordance with the invention will now be described by way of example and with reference to the accompanying drawings forming a part of this specification, in which:

Figure 1 is a side elevation, partly in section, of a suction box, the section being taken on the broken line 11 of Figure 2,

Figure 2 is an end elevation, also partly in section, the section being taken on the line 2-2 of Figure 3;

Figure 3 is a plan view, also partly in section; and

Figure 4 is a view, similar to Figure 2, showing a modified construction.

The suction box, according to Figures 1-3, which is conveniently an iron casting, is supported on the floor 10 of the tank by feet 11 located one at each corner of the box and formed by downward extensions of the sides 12, 13 and the ends 14, 15 of the rectangular lower part of the box.

Within the hollow interior of the box and extending between its ends 14, 15 are three pairs of interior walls defining inlet channels 16, 17, and 18, and cast integrally with the box. These walls are joined at the top, whereby three channels are shaped as inverted U-shaped tunnels that are isolated from the suction space above. The channels are open at their undersides and at each end through registering apertures in the end walls, 14 and 15, for the influx of liquid. The upper edges of the interior walls of the tunnels 16, 18 extend upwardly to provide enclosed heating passages or tubes 19, 2%, respectively, through which a heating medium such as steam can be circulated. The passages 19, 26 are connected together at their ends which open out through the end 14 of the box, by a pipe 21 that is bolted to flange faces 22 and 23 formed in the end 14. The other ends of the passages 19, 20 are provided with flange faces 24-, 25 formed on the end 15 of the box for connection to an external system (not shown) for supplying steam thereto and discharging spent steam or condensate therefrom. Conveniently such a system includes a tank grid such, for example, as the kind described in British patent specification No. 655,986.

The lower edges 26 of the interior walls that bound the U-shaped tunnels 16, 17, 18 define, together with the lower edges of the peripheral walls 12, 13, 14, 15 of the lower part of the box, four rectangular apertures A, B, C, D through which liquid can ascend to the upper part of the suction box. As will be seen from Figure 3 of the drawings, the total length of the boundary walls of these apertures A, B, C, D is considerably greater than the total length of the walls 12, 13, 14, defining the lower part of the box itself.

The upper part 27 of the box may slope upwardly towards a flanged outlet port 23 for connection to suetion pipe line (not shown) forming part of the tankevacuating system. The sloping upper wall 27 is provided with an inspection hole 29 fitted with a removable cover 3% through which access can be gained to the interior of the box for cleaning.

The provision of heating tubes 19, 29 within the interior of the suction box not only enables the viscosity of oil within the box to be reduced prior to tank evacuation but also enables heat to be imparted to the oil actually being withdrawn from the tank thereby to reduce its viscosity still further prior to its passage through the pump. 7

As will be seen from the drawings the suction box in accordance with the invention is a compact structure which can readily be removed as a unit when it is desired to inspect the floor of the tank. Moreover it can be easily cleaned and inspected. Since also the box lends itself to foundry production, it is suitable for production as a casting in which the problem of corrosion in service will not arise.

The suction box is moreover equally efiective for the evacuation of liquids of which the viscosity is such that heating to reduce viscosity drag is unnecessary.

it is evident that the tubes 19, may be used merely to receive separate heating pipes through which the heating medium is passed, without subjecting the casting itself to the pressure of that medium, or to contain electrical heating elements.

Referring to Figure 4-, there is shown a modification in which the heating tube is mounted within the inlet channels. In this view, wherein like reference characters denote parts previously described, the heatingtube'is a U-sh d pipe 31 having a pair of flanges 32 near the ends oi: the curved part. The'pipe has the straight legs thereof positioned horizontally within the upper parts of the inlet channels and is supported by bolting the flanges to the outsides of the box, which has suitable bolting surfaces for this purpose; only one of the flanges 32 appears being open at the bottom and having an end inlet through an aperture of ample size in a peripheral wall for the influx of liquid, the lower edges of said peripheral and interior walls being closely spaced from said floor and having an aggregate length in excess of six times the widest portion of said box to define with said floor a' horizontally elongate inlet aperture to the suction space,

' and a heating element extending along said channel at a height above the lower edges of said interior Walls.

2. x" box'according to claim 1 wherein said interior walls include at least two pairs of walls, each said pair of interior walls being joined at the top to define a separate inlet channel and each said channel traversing the full distance between opposed peripheral walls and having at each end thereof an inlet through an aperture of ample size in the respective peripheral wall.

3. A suction box according to clairnl wherein the said heating element includes a tube situated immediately above said joined interior walls.

4. A suction box according to claim 1 wherein the said heating element includes a tube situated within the said inlet channel.

5. A suction box according to claim 1 wherein said heating element includes a pair of heating tubes extending entirely through the box between opposite wallsthereof, said tubes being coupled to one another outside the periphery of the box to form a single circuit for the transmission of said heating medium.

6. A suction box for evacuating liquids from storage tanks comprising peripheral walls enclosing a suction space and at least one pair of interior walls extending between opposite peripheral walls, at least one pair of interior walls defining an inlet channel and beingjoined at the top of the channel to isolate the said channel from said suction space, said inlet channel traversing the base of the box entirely between said opposite peripheral walls and opening at both ends through corresponding apertures of ample size in the said opposite peripheral walls fer the influx of liquid, said box having means at the bottom for engaging a tank floor, both said peripheral and interior walls having lower edges closely spaced from said floor to define with said floor a horizontally elongate inlet aperture for the influx of liquid into said suction space, said walls having further an outlet port adapted for connection to a suction pipe.

References Cited in the file of this patent UNITED STATES PATENTS France Aug. 1, 1932

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