Reexamination Certificate
1999-01-13
2001-11-27
Stinson, Frankie L. (Department: 1746)
C134S16700R, C134S16700R, C134S172000, C134S113000
Reexamination Certificate
active
06321754
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for washing tanks to clean out, for example, sludge and other such solid matter that collects at the bottom of crude oil tanks and other such tanks used to store relatively large quantities of liquid, and to a tank washing method using the apparatus.
2. Description of the Prior Art
Manually washing out large-capacity tanks such as tanks used to store crude oil is a lengthy process, involving as it does the risk of fire and health risks in a closed environment. In addition, it is difficult to recover oil components from tank sludge. Owing to such factors, a method of washing tanks that is in widespread use involves the use of a machine that emits a pressurized jet spray of washing liquid, the machine being installed in the floating roof or other such roof portion of the tank with the spray directed into the tank. Sludge that has collected at the bottom of the tank is thus broken down and cleaned out by spraying the sludge with clean oil or the like under pressure (U.S. Pat. No. 4,426,233).
At the time of the washing process the floating roof in which the spraying machine is installed is at a height of around two meters from the floor of the tank. This means that the effective floor washing distance of the washing liquid sprayed from the spraying machine is short, which necessitates the installation of multiple spraying machines. A floating roof type tank having a diameter of 100 meters and a height of 20 meters, for example, is equipped with some 35 spraying machines. However, this type of arrangement has a number of problems, including the following.
1. Many spraying machines are required. Large quantities of equipment such as pipes and valves, are required for the temporary installations.
2. Installing and removing the equipment requires a lot of man hours and time.
3. Large lifting equipment is required to hoist the equipment onto the roof and remove it.
4. The large number of spraying machines involved makes the operation and maintenance thereof complicated.
5. While an installation may comprise as many as 30 or more spraying machines, there are times when only two or three can be operated, so the operating efficiency of the spraying machines is poor.
6. Replacement and maintenance of spraying machines take time and work, with the workers involved having to raise and lower the tank of 20-meter height each time. Thus, any problems such as leaks happening to equipment on the roof cannot be promptly tackled.
7. Some roof supports are removed to install spraying machines, increasing the load on the surrounding parts of the removed roof supports, which is undesirable in terms of strength and safety.
8. The large numbers of man hours and large quantities of equipment involved push up the costs.
An object of the present invention is to provide a tank washing apparatus and method that can be readily set up, reliably fluidize accumulated solid matter such as sludge and efficiently expel the same from the tank, regardless of what liquid has been stored in the tank.
SUMMARY OF THE INVENTION
Equipment installations on the roof of the tank can be substantially or completely eliminated and temporary installations and washing operations implemented on the ground by the method and structure described below.
A spraying machine that sprays washing liquid is inserted into a manhole, mixer hole or other such through-hole provided in a lower side wall portion of the tank, and the spraying machine operated therein.
The number of such through-holes is limited to three or four, so the number of installed washing apparatuses is also thus limited. If each of such a small number of washing apparatuses is used in a fixed location, the effective washing distance of the washing apparatuses (spraying machines) will not be enough to cover the total area inside the tank, so there will remain some portions that are not sufficiently washed.
To avoid this, in accordance with the present invention the spraying machine that sprays the washing liquid is moved within the tank.
Specifically, in order to attain the above object, the present invention provides a tank washing apparatus comprising a cover that is detachably attached to a through-hole in a tank, a travelling apparatus that is movable as desired by being operated from outside the tank, a spraying machine that is mounted on the travelling apparatus for spraying washing liquid, and a supply conduit for supplying washing liquid, the supply conduit being connected to the spraying machine via the cover.
The above object is also attained by a method of washing a tank using the tank washing apparatus, comprising moving the travelling apparatus that is movable as desired by being operated from outside the tank and using a jet of washing liquid sprayed under high pressure from the spraying machine to fluidize solid matter including sludge on a floor portion of the tank.
The travelling apparatus used in this invention is one that is able to move even in the presence of oil and sludge. The travel structure may be a vacuum suction system, a caterpillar system, a crawler system or other such type of system.
The travelling apparatus can be remotely operated from outside the tank. This remote operation can be effected by, for example, mounting a hydraulic motor on the travelling apparatus and externally controlling the supply of hydraulic fluid to the hydraulic motor. However, the method of operation is not limited thereto, and any operating method may be employed.
The spraying machine mounted on the travelling apparatus may be equipped with a mechanism for effecting turning and reciprocating motion in vertical and horizontal directions, and an arrangement may be used that allows the angle of reciprocation and reciprocation velocity to be adjusted. It can also be made possible to effect such an operation from outside the tank.
Other than that the supply conduit for supplying washing liquid to the spraying machines does not restrict the movement of the travelling apparatus, there is no particular limitation on the material or structure of the supply conduit. The conduit may, for example, be in the form of a pipe constituted of a flexible material, or a telescopic pipe, or a movable pipe.
Thus, instead of the conventional arrangement in which washing apparatuses are installed on the roof of the tank, the washing apparatus of the present invention is inserted into the tank via a through-hole such as a manhole or mixer hole in the lower part of the side wall of the tank. Then, inside, the washing apparatus is moved around on the floor of the tank as desired to effect the washing operation. This makes it possible to wash a tank efficiently using a low number of washing apparatuses. In addition, it makes the piping work easier and enables the operation to be done in safety.
REFERENCES:
patent: 1857766 (1932-05-01), Peterson
patent: 2109075 (1938-02-01), Ruth
patent: 2116935 (1938-05-01), Richard et al.
patent: 2681250 (1953-01-01), Metcalf et al.
patent: 2858836 (1958-11-01), Geh et al.
patent: 3150669 (1962-04-01), Green
patent: 3595256 (1971-07-01), Waltman
patent: 3645452 (1972-02-01), Stoeckel et al.
patent: 3741808 (1973-06-01), Stalker
patent: 4163455 (1979-08-01), Hebert et al.
patent: 4393920 (1983-07-01), Shima et al.
patent: 4577411 (1986-03-01), Martin
patent: 4646768 (1987-03-01), Tanaka et al.
patent: 4770711 (1988-09-01), Deal, III et al.
patent: 4784166 (1988-11-01), Brager et al.
patent: 4817653 (1989-04-01), Krajicek et al.
patent: 5009242 (1991-04-01), Prange
patent: 5035556 (1991-07-01), Lamotte et al.
patent: 5065703 (1991-11-01), Lee
patent: 5293887 (1994-03-01), Thibodeaux
patent: 5522410 (1996-06-01), Meilleur
patent: 5563787 (1996-10-01), Murayama
patent: 5640982 (1997-06-01), Landry et al.
patent: 5642745 (1997-07-01), Landry et al.
patent: 5740821 (1998-04-01), Arnold
patent: 5932026 (1999-08-01), Trampusch
patent: 5944036 (1999-08-01), Allen
patent: 42 22 007 (1994-01-01), None
patent: 2 227 647 (1990-08-01), None
patent: 315327 (1997-09-01), None
Goto Takahiro
Manabe Nobuyuki
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Stinson Frankie L.
Taiho Industries Co. Ltd.
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