US3420444A - Apparatus for washing the cargo tanks of ships,particularly oil tankers - Google Patents

Description

3,420,444 PARTICULARLY Sheet Jan. 7, 1969 K. G. AJNEFORS APPARATUS FOR WASHING THE CARGO TANKS OF SHIPS ofa OIL TANKERS Filed June 14, 1966 3,420,444 TICULARLY Sheet 2 of 2 J n- 7, 1969 K. G. AJNEFORS APPARATUS FOR WASHING THE CARGO TANKS OF SHIPS, PAR

I OIL TANKERS Filed June 14, 1966 Fig.2

United States Patent Office 3,420,444 APPARATUS FOR WASHING THE CARGO TANKS F SHIPS, PARTICULARLY OIL TANKERS Karl Gunnar Ajnefors, Goteborg, Sweden, assignor to Salen & Wicander AB, Solna, Sweden, a corporation of Sweden Filed June 14, 1966, Ser. No. 557,450 Claims priority, application Sweden, June 14, 1965, 7,829/65; May 12, 1966, Ser. No. 6,534/66 US. Cl. 239-227 3 Claims Int. Cl. B05b 3/14 ABSTRACT OF THE DISCLOSURE The present invention relates to an apparatus for washing the cargo tanks of ships, particularly oil tankers, which apparatus includes a jet nozzle that depends downwardly into the cargo tank and which is connected to means for both rotating the nozzle about a vertical axis and means for oscillating the nozzle about a horizontal axis between an upper and a lower annular limit position.

Such apparatus are previously known to the art, in which the tank-washing operation is carried out by the use of forceful jets of water ejected through a nozzle connected to a source of water under pressure and revolving continuously in one single sense about a horizontal axis which rotates slowly about a vertical axis so as to cause the water jets successively, or incrementally, to sweep all surface elements of the bottom, walls and ceiling of the cargo tank. However, it may not always be necessary, or even desirable, to wash all portions of a cargo tank, and in such cases the prior art apparatus operates at an unreasonably slow rate and involves an unnecessary waste of water and power.

The present invention has for its object to remedy this drawback by providing a washing apparatus in which the jet nozzle is arranged, in the course of its rotary motion about the vertical axis, to execute an oscillatory motion about its horizontal axis between an upper and a lower angular limit position. The angular limit positions thus defined are suitably adjustable to enable the width and localization of the zone to be swept by the water jet to be selected at will, for instance to enable washing of the bottom only of the cargo tank.

For transmitting the desired rotary and oscillatory motions to the nozzle, an operating mechanism is provided which is connected to the jet nozzle through movementtransmitting elements. According to a preferred embodiment of the invention, the operating mechanism is arranged to rotate the nozzle at a relatively high rate about the vertical axis, and to oscillate the same at a substantially slower rate about the horizontal axis, thereby causing the spot of impingement of the jet on the cargo-tank wall to move along substantially horizontally extending paths suitably spaced from one another. In this case, the operating mechanism may be arranged to rotate the nozzle through several revolutions in one sense about the vertical axis, while slowly swinging the nozzle about its horizontal axis between the two angular limit positions, thereby causing the jet from the nozzle to sweep the cargotank wall along a helical path within a horizontally closed, but vertically limited zone. As an alternative, the operating mechanism may be so designed as to turn the nozzle reciprocatorily about the vertical axis between predetermined angular limit positions, while the nozzle is carrying out its slow swinging motion about the horizontal axis, whereby the jet spot on the cargo-tank wall will follow a zigzag path within a zone which is delimited laterally, as well. In the preferred embodiment it is of 3,420,444 Patented Jan. 7, 1969 particular advantage to arrange the operating mechanism in such a way that it will automatically reverse the direction of swinging motion of the jet nozzle at the angular limit positions so as to cause the zone to be washed alternately from top downwards and from bottom upwards.

Alternatively, the operating mechanism may be so designed as to cause the jet nozzle to run through a plurality of cycles of oscillation at a relatively high angular velocity about the horizontal axis while turning slowly through one revolution about the vertical axis, thereby causing the spot of impingement of the water jet on the cargo-tank wall to describe a serpentine, or wave-shaped, path. In this case, the mechanism should be so devised as to displace the wave-shaped path laterally by a suitable angular amount per revolution of the jet nozzle about the vertical axis.

Further important features of the invention will become apparent from the following description of two embodiments thereof with reference to the accompanying drawings, in which:

FIGURE 1 illustrates the jet-nozzle mechanism proper in a first embodiment, the said mechanism being permanently mounted in a cargo tank, while FIGURE 2, on a larger scale, illustrates the operating mechanism which is designed as a detachable unit.

Depending through an aperture formed in the weather deck 10 of the vessel and centrally disposed relative to a cargo tank below this deck is a vertical pipe 13 which, through a pipe extension 12 of slightly larger diameter, communicates with a branch pipe 14 disposed on deck and to which a water pump, not shown, for instance the cargo pump, is connected. Pipe 13 is suspended from the deck by means of a flange plate 15 welded to the same. At its bottom end pipe 13 is terminated by a pipe extension 17 which is Sealingly rotatable relative to the pipe and has a closed bottom end. Sealingly and r0- tatably mounted in the side wall of the pipe extension 17 is a jet nozzle 18 which is bent through a right angle at a point which is spaced a short distance from its mounting end. By rotating the pipe extension 17 about the axis of the vertical pipe 13 and simultaneously swinging the jet nozzle 18 slowly about the horizontal axis, the outlet orifice of nozzle 18 can be caused to describe a helical path, either from top downwards or from bottom upwards, whereby the jet will sweep a wall-surface zone the position and vertical extent of which are determined by the upper and lower angular limit positions of the nozzle swinging about the horizontal axis.

The turning of the vertical plane of oscillation of the nozzle 18, i.e., the rotation of pipe extension 17, is effected through the intermediary of a tubular shaft 20 which is passed down through pipe 13 and has its lower end introduced into a central hole made in the bottom of the pipe extension and welded to this bottom, the upper end of shaft 20 projecting upward through an end wall on the extension 12 of pipe 13 on deck. Axially guided within tube 20 is a rod 25 having its upper end projecting a certain distance beyond the top end of the tubular shaft. Rod 25 carries at its lower end, which depends beyond the tubular shaft 20, a disc 26 which is guided for axial movement 'by means of three guide rods 27 secured to the bottom of pipe extension 17 and passed through corresponding holes made in said plate. Rods 27 carry at their lower ends a plate 28 formed with a radial projection 29 adapted to limit the swinging movement of nozzle pipe 18 in the downward direction. The disc 26 connected to rod 25 carries a pivot pin 39 having journalled thereon one end of a link 40 the opposite end of which is pivoted on a pin 41 secured to the horizontally extending portion of nozzle 18. Pin 41 is disposed in laterally spaced relation to a vertical plane extending in parallel relation to the pin and containing the vertical axis of rotation of the nozzle pipe, so that upon moving the rod 25 upwardly from the position illustrated in FIGURE 1, the nozzle pipe 18 will be swung about its horizontal axis through the intermediary of link 40 from its downwardly directed position, as shown, to an upper position as indicated in broken lines.

The operating mechanism shown in FIGURE 2 comprises a frame generally designated by 50 and including a bottom member 51 and a top member 52 connected to the bottom member by four columns 53. Centrally mounted in the bottom frame member 51 is a gear wheel 54 which engages a smaller gear wheel or pinion 55 secured to a drive shaft 56 which can be rotated in the desired direction by any suitable motor 57, for instance a pneumatic motor. Between two spaced parallel plates 58 inside the top frame member 52 a nut 60 provided with a control wheel 59 is rotatably but axially nondisplaceably mounted. Passing through the nut 60 in threaded engagement therewith is a screw-threaded rod or lead-screw 61 carrying at its bottom end a shaftconnecting sleeve 62 provided with a key 63. Threaded onto the top end of lead-screw 61 is an adjustment nut 64 provided with a knob, as well as a lock nut 65 for this adjustment nut. The bottom frame member 51 is so designed and dimensioned as to enable the entire operating mechanism to be bodily disposed on, and clamped to, the extension 12 of pipe 13 projecting above the deck by means of screws, not shown, engaging holes made in lugs formed on the pipe extension 12. The tubular shaft is then pushed into the hub of gear 54 with two keys 67 secured to the gear in diametrically opposed positions entering corresponding key slots 68 formed in shaft 20, while the connecting sleeve 62 is passed over the rod and is secured to the latter by means of a key 63.

After the operating mechanism unit has thus been mounted in place, rod 25, by turning the wheel 59, is moved upward to an extent such as to swing the jet nozzle pipe 18 to its desired lower angular limit position. Then the motor 57 is started in a direction to cause the rod 25 which is rotated together with the tubular shaft 20, to be screwed downward again through nut 60. Obviously, during each revolution of the tubular shaft 20 and rod 25, respectively, about the vertical axis, the rod 25 will be displaced axially by a length corresponding to the pitch of the screw thread, thereby swinging the nozzle pipe 18 through a corresponding angle about its horizontal axis. Thus, the jet ejected by the nozzle will impinge the wall at a spot describing a helical path from top downwards within a horizontally extending zone having a vertical width determined by the limit positions of the jet nozzle. Upon reaching the bottom limit position, the direction of rotation of drive motor 57 may be reversed, after which the jet will sweep the same zone in a helical path from bottom upwards.

It is a simple expedient to make provision for the reversal of the drive motor at the top and bottom angular limit positions of the jet nozzle to occur in a completely automatic way. As shown in FIGURE 2, the adjustment nut 64 is formed at its bottom end with an annular flange 70 cooperating with two control devices 71 and 72, such as air valves, which control the direction of rotation of the drive motor and are vertically adjustable into different positions. When during the downward movement of the rod 25 and lead-screw 61 the annular flange 70 impinges the control device 71, the direction of rotation of the drive motor will be reversed so that the rod will again begin to move upwardly, and when the upper limit position is reached, the flange will engage the control device 72 causing the latter to initiate reversal of the motor to its original direction of rotation. Arrangements in which the reversal of a motor is controlled by control devices adjustable to desired limit positions are previously known to the art, and therefore, need not be described here in detail.

By providing the control wheel 59 of nut 60 with gear teeth and connecting the same to a suitable source of driving power, it is possible, without reversing the direction of rotation of the tubular shaft 20 and rod 25, to cause the jet nozzle 18 to move in helical paths which on swinging downward from top are different from those obtained on swinging upward from bottom. If the wheel 59 is rotated in the same sense as the screw spindle or lead-screw 61 and rod 25, but at the double angular velocity, then the axial movement of the rod will be reversed with unchanged speed. The rotation of nut 60 may be effected from the drive shaft 56 through any suitable gear train which may be releasably coupled to the shaft, although, of course, a separate drive motor may be employed for this purpose.

It should be understood that the invention is not restricted to the embodiments described in detail hereinbefore, since various modifications are conceivable without departing from the scope of the invention.

I claim:

1. Apparatus for washing the cargo tanks of ships, particularly oil tankers, which comprises:

(a) a first vertical pipe that is adapted to be mounted in the aperture of a weather deck and which depends downwardly into a cargo tank below said weather deck,

(b) a pipe extension located on the bottom end of said first vertical pipe, said pipe extension being mounted on said first vertical pipe so that it is sealingly rotatable relative to said first vertical pipe,

(c) a jet nozzle sealingly and rotatably mounted in the side wall of said pipe extension, said jet nozzle being bent through approximately a right angle at a point which is spaced a short distance from its mounting end,

(d) a tubular shaft axially disposed within said first vertical pipe so as to leave an axial passageway therebetween, the upper end of said tubular shaft extending beyond the upper end of said first vertical pipe and the lower end of said tubular shaft extending below the lower end of said first vertical pipe and being fixedly attached to the bottom side of said pipe extension,

(e) a rod axially disposed within said tubular shaft,

the upper end of said rod projecting above the upper end of said tubular shaft, and the lower end of said rod extending downwardly below the lower end of said tubular shaft,

(f) a disc fixed to the lower end of said rod,

(g) guide rods secured to the bottom of said pipe extension and extending downwardly therefrom, said guide rods serving to guide said disc along an axial path that is parallel to the axis of said rod,

(h) said disc being connected to said nozzle by means of a pivotable link member,

(i) means for limiting the are through which the jet nozzle may oscillate about a horizontal axis,

(j) a first means for raising and lowering said rod,

(k) a second means for rotating said tubular shaft,

(1) said first and second means being adapted to operate simultaneously so as to rotate said nozzle at a relatively high rate about the vertical axis while at the same time oscillating the nozzle at a substantially slower rate about a horizontal axis, there by causing the spot of impingement of the jet on the wall of a cargo tank to move along a helical path within a horizontally closed but vertically limited zone.

2. Apparatus for washing the cargo tanks of ships,

particularly oil tankers, which comprises:

(a) a jet nozzle which is swingable about a support having a horizontal axis, (b) said support that has a horizontal axis being in 5 6 turn rotatable about a support having a vertical about the horizontal axis each time the nozzle has axis, reached its upper or lower angular limit position. (c) said jet nozzle being adapted, under the control 3. An apparatus according to claim 2 characterized in of an operating mechanism connected thereto that the operating mechanism is connected to the nozzle through movement transmitting means, to execute, through the intermediary of a rotatable and axially dissimultaneously with its rotary motion about the ver- 5 placeable, screw-threaded rod co-operating with an axtical axis, an oscillatory motion about the horizonially fixed nut.

t-al axis between an upper and a lower angular limit References Cited Posmon, UNITED STATES PATENTS ((1) said operating mechanism being arranged to rotate 10 the nozzle through several revolutions in one single i fi g 1 x Moiren 239227 direction about the vertical axis while swinging the 3 3 g 239*227 X nozzle only once between the two angular limit posi- X 0rd 239*227 X 2,785,008 3/1957 Young 239--227 trons about the horizontal axis, so as to cause the 3 265 30 8/1966 spot of impingement of the jet on the cargo-tank 15 9 Hammelmann 239 227 X wall to descnbe substantlally horlzontally extendmg M HENSON WOOD, JR. Primary Examiner paths suitably spaced from one another,

(c) said operating mechanism also being constructed HOWARD NATTER, Assistant Examinerso that while maintaining the direction of rotation Us c1- XR. of the nozzle about the vertical axis, it can reverse 20 239 263 264 i the direction of swinging movement of the nozzle

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