US2991203A

US2991203A - Method and apparatus for cleaning the interior of a tank

Info

Publication number: US2991203A
Application number: US770168A
Authority: US
Inventors: Cornelis In T Veld; Johannes In T Veld
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-10-31
Filing date: 1958-10-28
Publication date: 1961-07-04
Anticipated expiration: 1978-07-04
Also published as: GB867384A; NL96409C; DE1156625B

Description

July 4, 1961 c. IN 'T VELD ETAL 2,991,203

METHOD AND APPARATUS FOR CLEANING THE INTERIOR OR A TANK July 4, 1961 C, |N T VELD ETAL 2,991,203

METHOD AND APPARATUS FOR CLEANING THE INTERIOR OF A TANK Filed OGt. 28, 1958 3 Sheets-Sheet 2 INVENTORS Comvs L1 s :Uv T VELD BY Taunumislv VELD A Trozw e' y July 4, 1961- c. 1N 'T VELD ETAL 2,991,203

METHOD AND APPARATUS FOR CLEANING THE INTERIOR OF' A TANK Filed Oct. 28, 1958 3 Sheets-Sheet 5 ATTORNEY United States Patent O 2,991,203 METHOD AND APPARATUS FOR CLEANING THE INTERIOR OF A TANK Cornelis in t Veld, 12 Burg. Luijerinksingel, and J0- lrannes in t Veld, 13 Burg. Luijerinksingel, both of Vlaardingen, Netherlands Filed Oct. 28, 1958, Ser. No. 770,168 Claims priority, application Netherlands Oct. 31, 1957 7 Claims. l(Cl. 134-24) The invention-concerns a method and an apparatus for cleaning the interior of a tank of, for instance, a tanker, a shore installation or the like, according to which a cleaning liquid is ejected from nozzles which are rotatable about a horizontal transverse axis, said nozzles forming part of an apparatus which itself is rotatable about a vertical axis. A similar method and apparatus are known from the Dutch patent specification No. 32,888, according to which two nozzles rotating in parallel vertical planes about a horizontal axis perform at the same time a movement about a vertical axis of rotation. In this treatment the cleaning liquid is delivered inv equal quantities towards the top and the bottom. Because the body of revolution of these rotating nozzles here described with each revolution has as points of intersection the points perpendicularly below and above the apparatus, relatively large quantities of liquid are sprayed on and about these points of intersection. In such tanks, however, the largest amount of dirt isto be found on the lower part of the side-walls of the tank and in the corners, in particular the lower corners near the bottom, towards which parts relatively small quantities of cleaning liquid are sprayed by the known method. The cleaning liquid usually employed is hot water under a pressure of about l2 atm. QuantitiesV ofabout 80 tons/hour ,are

ice

- adjustment where the jets act in the corners of Ithe tank,

- to be entirely adjusted to the dirtiest place, so that too required for this, and it will be Yevident that such a quantity of hot water under high pressure is an expensive liquid, for the production of which aygood deal of power is needed. If the cleaning of the tanks of a steam-driven tanker has to be carried out during navigation, the amount of power required for thisis frequently j so great that the tanker cannot sail on normally, but has zzo reduce its speed considerably. j

Now the invention has for its object to furnish a method and apparatus by means of Vwhich it is possible to carry out the cleaning of a tank in a way which is more eiiicient and also involves a saving of liquid.

` According to the invention this object is achieved by the fact that for the duration of one cycle of treatment the nozzles, performing a given number of revolutions about the vertical axis, are simultaneously adjusted only once'from the top to the bottom. Whilst therefore according to the known methods the jets act upon the Walls of the tank accordingto curved lines extending side by side from the top to the bottom, in accordance with the invention the action upon the walls takes place according to a spiral line on the top and bottom surfaces and according to helical lines on the side-walls of the tank. According to the invention it is possible to control the nozzles in such a way during their adjustment about the horizontal axis that the action of the jets is shorter on those surfaces which are less dirty and longer on those which are dirtier. According to theinvention the adjustment of the nozzles about the horizontal axis may therefore take place withvarying speed, a slower adjustment in particular taking place in those ranges of much cleaning liquid is sprayed in all other less dirty places. This excessive use of cleaning liquid can be avoided by the method according to the invention because in consequence of a ready adjustment of the nozzles the jets can move quickly over the less dirty surfaces and according to the inventionthe adjustment in the corners takes place more slowly, In fact, in these corners greater demands are made on the cleaning in connection with the Irelative increase of the area to be cleaned and the presence of additional surfaces, connected with the construction of the tank.

- Further it is no longer necessary to use the same nozzle in the upper range of the tank and in the lower range, so that nozzles of different diameters can be employed for theseranges, which involves a further saving of` cleaning liquid. Even apart from the better cleaning in the corners which is possible `with the method according to the invention, a saving of about 3,000.- is obtained during the cleaning of a tanker, so that the cost of the apparatus for carrying out the method is already amply Irecovered in one treatment. v

The apparatus for carrying out the method according to the invention may be formed by a casing adapted to rotate about a -vertical axis relative to its suspension through which casing the cleaning liquid is fed, while on the outside it is iitted with one or more nozzles'rotatable about a horizontal transverse axis, which nozzles are connected with means for adjusting these nozzles. In order to obtain different quantities of liquid for the treatment of the upper and the lower part of a tank respectively, according to the invention near each horizontal transverse axis two nozzles connected with each other and with the operating means may be provided, which nozzles include an angle of about with each other and can be adjusted over a corresponding angular range. The nozzle which then covers the upper part of the-tank may have a smaller outlet opening than the other nozzle.

According to the invention each nozzle or each set of nozzles may be connected with a vertically adjustable body engaging the helical threads of a member-driven so as to rotate about a vertical axis, the helical threads of said member, which bring about the downwardr vadjustment of the nozzles, having a variable pitch, while further a return thread with a considerably greater pitch running in the opposite direction is present. The helical threads of dilferent pitch cause the nozzles in given ranges to be adjusted more slowly than in other ranges, while at the end of thecycle an accelerated return to a new starting position takes place. Owing to this variable pitch the nozzles can move more quickly over the upper side and lower surfaces of the tank and act for a longer time upon the angular ranges of the tank. 'q l According to the invention, in the casing there may be mounted a turbine driven by the flow of the liquid,l which turbine drives, via a reduction gear, the casing rotating about the vertical axis and also, via a second reduction gear, the member provided with helical threads.'` This type of drive provides for the rotation about 'the vertical axis of rotation and for the slow adjustmentof the nozzles about the horizontal axis as well as the readjustment to the new starting position, upon which the cycle may be repeated again, if necessary.

The invention will now be explained more fully with reference to the drawings, which illustrate an embodiment of the apparatus for carrying out the method according to the invention.

-FIGURE 1 is a vertical cross-section of the apparatus according to the invention.

FIGURE 2 is a horizontal cross-section along the line -II-II in FIGURE 1.

FIGURE 3 is a horizontal cross-section along the line III- III in FIGURE l.

FIGURE 4 is a cross-section of a part of FIGURE 3 along the line IVIV.

FIGURE 5 is a vertical section on a smaller scale of a tank and cleaning apparatus embodying the invention.

The apparatus shown inthe drawings consists. of a protective protective cap and handle 1, a casing 2, which is provided with a connection (not shown) for feeding cleaning liquid to the interior 3 of said casing. On this casing 2, which is stationary during the operation of the apparatus, via a ball bearing 4 the casing 5 of the apparatus is rotatably suspended.

Near the lower end this casing 5 is constructed to have rubber-lined laterally extending lugs 6, near which a sleeve 7 is rotatably supported, from which sleeve extend two

nozzles

8 and 9 respectively, which nozzles practically include an angle of 90 with each other, but are placed the former at a small angle inwards towards the vertical and the latter at a small angle upwards towards the horizontal. This is necessary in order to prevent certain sur.l faces not being sprayed and to obtain overlapping.

The casing 5 is closed at the bottom by a cover 10, on which are fixed columns 11 directed vertically upwards. These columns 11 serve as guides for blocks 12 movable along them, which blocks are fitted with stub axles 13, arms 14 extending into bushings 15 of the sleeve 7, rotatable about a horizontal transverse axis, being supported on said stub axles. When the blocks 12 are moved upwards along the columns 11, the rods 14 will move in the bushings 15, with the simultaneous rotation of the sleeve 7 and consequently of the

nozzles

8 and 9. The blocks 12 are fitted with a member 16 meshing with a helical thread of a member 17 rotatable afbout a vertical axis. The helical threads of this member 17 have a variable pitch, in the sense that the pitch is greater at the lower and the upper ends where the nozzles are in registration with the at wall surfaces than in the central section where the nozzles are in registration with the more remote corner sections of the tank. The return thread 17b is of greater pitch than the thread 17a so that the nozzles are returned at a more rapid rate for repeating the cycle.

Both the casing 5 and the member 17 tted with threads are power-driven, for which purpose in the upper part of the casing 2 a turbine 18 is mounted, which drives a shaft 19 supported in the innermost .part of the casing. This shaft 19 carries a worm screw 20, also shown in FIGURE 2, and this worm screw drives a worm wheel 21 of a shaft 22, on which a second worm 23 is mounted. This worm 23 meshes with a worm wheel 24 of a shaft 25, at the upper end of which is located a gear wheel 26 meshing with an internal gear 27 of the casing 5. In this way the casing S is driven with great reduction, so that it rotates about the vertical axis and thus also im parts a similar rotation to the nozzles. At the lower end of the shaft 25 is located a second gear wheel 28, also meshing with an internal gear 29, which is connected with the member 17 tted with helical threads, by which means the latter is driven. This drive results in the upward movement of the blocks 12 and accordingly` in the rotation of the nozzles.

'Ihe cleaning liquid ows through the hollow interior of the

casings

2 and 5, and can enter via the ends of the sleeve 7 into the interior of the latter and leave it via the nozzles fitted on the sleeve. To this end the bushings at the ends near the guide bushing 15 for the rod 1-4 are shaped in the way indicated in FIGURE 4. The nozzles are adjusted over an angle which is slightly greater than so that sufficient overlapping is obtained.

It will be evident that instead of the driving mechanism for the adjustment of the nozzles it is also possible to use other mechanisms or even manual operation, by means of which the adjustment is effected by hand in a simple way, from the top.

It is further to be noted that after each cycle of treatment the next cycle starts in another point, so that upon repetition of the treatment the lines described on the walls differ from those of the preceding cycle.

The apparatus above described is shown in FIG. 5 as positioned for cleaning a tank having a top wall 30 provided with an opening 31 through which the apparatus is inserted and having side walls 32 and a bottom wall 33. 'Ihe nozzles are so disposed that one set of nozzles cleans the top wall 30 and the upper portion of the side wall 32, while the other set of nozzles cleans the lower portion of the side wall 32 and the bottom wall 33.

What we claim is:

1. The method of cleaning deposits from the interior walls of a tank or the like having top, bottom and side walls, which comprises spraying onto the interior surfaces of said walls a cleaning liquid from a plurality of nozzles within said tank, said nozzles extending normal to a horizontal axis and being spaced laterally from a given vertical axis while rotating said set of nozzles about said vertical axis at a uniform rate and simultaneously oscillating said nozzles about said horizontal axis in such an arc that liquid from certain of said nozzles impinges on the top and upper side walls of said tank and liquid from others of said nozzles impinges on the bottom and lower side walls of said tank and discharging a larger quantity of said liquid from the last mentioned nozzles than from the iirst mentioned nozzles to compensate for the greater quantity of deposit to be removed from the lower portion of said walls.

2. The method set lforth in claim 1 in which said nozzles are arranged in pairs displaced relatively by about 90 with respect to said horizontal axis and are oseillated in an arc of the order of 90.

3. Apparatus for cleaning deposits from the interior surfaces of a tank or the like having top, bottom and side walls, comprising a casing -to be disposed within said tank and mounted to rotate about a vertical axis, a plurality of sets of nozzles mounted on said casing to be oscillated about horizontal axes, said nozzles extending normal to said horizontal axes and being displaced from said vertical axis, means for oscillating certain nozzles of each set in an arc adapted to cause the liquid therefrom to contact the top and upper side walls only of said tank and means for oscillating other nozzles of each set in an arc adapted to cause the liquid therefrom to contact the bottom and lower side walls only of said tank, and means simultaneously rotating said casing about said ver. tical axis for thereby causing said liquid to contact said walls around the entire periphery of said tank.

4. An apparatus as set forth in claim 3 in which said last mentioned nozzles are adapted to discharge a greater quantity of liquid than said tirst mentioned nozzles to compensate for the greater quantity of deposit to be removed from the lower portion of said walls.

5. An apparatus as set forth in claim 3 in which said nozzles are arranged in pairs, the nozzles of each pair being relatively displaced by about 90 with respect to said horizontal axes and wherein means is provided to cause said nozzles to oscillate about said horizontal axes through an arc of the order of 90.

6. An apparatus as set forth in claim 5 wherein means is provided to cause the nozzles to oscillate at a greater rate at the extremities of their path of travel than at the center portion of their path of travel.

7. An apparatus as set forth in claim 3 wherein said means for oscillating said nozzles includes 4means to -feed said nozzles downwardly at a predetermined rate and means for returning said nozzles upwardly at a predetermined faster rate.

References Cited in the file of this patent UNITED STATES PATENTS Franklin Iuly 19, 1892 Morse June 24, 1919 Butterworth May 26, 1931 Lewis Oct. 24, 1939 Kennedy July 26, 1955 Scruggs July 23, 1957

Claims

1. THE METHOD OF CLEANING DEPOSITS FROM THE INTERIOR WALLS OF A TANK OR THE LIKE HAVING TOP, BOTTOM AND SIDE WALLS, WHICH COMPRISES SPRAYING ONTO THE INTERIOR SURFACES OF SAID WALLS A CLEANING LIQUID FORM A PLURALITY OF NOZZLES WITHIN SAID TANK, SAID NOZZLES EXTENDING NORMAL TO A HORIZONTAL AXIS AND BEING SPACED LATERALLY FROM A GIVEN VERTICAL AXIS WHILE ROTATING SAID SET OF NOZZLES ABOUT SAID VERTICAL AXIS AT A UNIFORM RATE AND SIMULTANEOUSLY OSCILLATING SAID NOZZLES ABOUT SAID HORIZONTAL AXIS IN SUCH AN ARC THAT LIQUID FROM CERTAIN OF SAID NOZZLES IMPINGES ON THE TOP AND UPPER SIDE WALLS OF SAID TANK AND LIQUID FROM OTHERS OF SAID NOZZLES IMPINGES ON THE BOTTOM AND LOWER SIDE WALLS OF SAID TANK AND DISCHARGING A LARGER QUANTITY OF SAID LIQUID FROM THE LAST MENTIONED NOZZLES THAN FROM THE FIRST MENTIONED NOZZLES TO COMPENSATE FOR THE GREATER-QUANTITY OF DEPOSIT TO BE REMOVED FROM THE LOWER PORTION OF SAID WALLS.

3. APPARATUS FOR CLEANING DEPOSITS FROM THE INTERIOR SURFACES OF A TANK OR THE LIKE HAVING TOP, BOTTOM AND SIDE WALLS, COMPRISING A CASING TO BE DISPOSED WITHIN SAID TANK AND MOUNTED TO ROTATE ABOUT A VERTICAL AXIS, A PLURALITY OF SETS OF NOZZLES MOUNTED ON SAID CASING TO BE OSCILLATED ABOUT HORIZONTAL AXES, SAID NOZZLES EXTENDING NORMAL TO SAID HORIZONTAL AXES AND BEING DISPLACED FROM SAID VERTICAL AXIS, MEANS FOR OSCILLATING CERTAIN NOZZLES OF EACH SET IN AN ARC ADAPTED TO CAUSE THE LIQUID THEREFROM TO CONTACT THE TOP AND UPPER SIDE WALLS ONLY OF SAID TANK AND MEANS FOR OSCILLATING OTHER NOZZLES OF EACH SET IN AN ARC ADAPTED TO CAUSE THE LIQUID THEREFROM TO CONTACT THE BOTTOM AND LOWER SIDE WALLS ONLY OF SAID TANK, AND MEANS SIMULTANEOUSLY ROTATING SAID CASING ABOUT SAID VERTICAL AXIS FOR THEREBY CAUSING SAID LIQUID TO CONTACT SAID WALLS AROUND THE ENTIRE PERIPHERY OF SAID TANK.