Background of the Invention
The present invention relates to installations for the recovery of liquid pollutants floating on the surface of water, for example, petroleum, and particularly the recovery and preliminary refinement of the collected pollutant so as to provide a nearly usable petroleum product.
Occasionally, large volumes of petroleum are discharged into navigable streams and waterways as the result of either accidental discharge from a petroleum carrying tanker, or an off-shore drilling rig. In such instances a pollutant results which usually consists of a pure petroleum and a petroleum scum or sludge which floats onor near the surface of the water. In addition to the large financial loss which can result from the loss of such large quantities of petroleum itself, the substantial damage can result to the marine life and the shoreline adjacent to the vicinity where such accidents occur. As a result, it is extremely desirable to remove the pollutant from the surface of the water before any substantial damage can occur. Not only is the recovery of the petroleum desirable, it is also important that the recovery cost be maintained at a minimum, and that the recovered petroleum be relatively pure so that little or no further processing be required in order to render it usable.
Summary of the Invention
The present invention contemplates providing an improved installation for the recovery of spilled petroleum from navigable streams or waterways. More particularly, the installation comprises a main vessel adapted to be propelled along the stream or waterway and is equipped with a receiving tank for receiving the pollutant thereon. The receiving tank is supported by the main vessel so as to enable it to float independently thereof. A scoop assembly is operably connected to the receiving tank for skimming the pollutant from the surface of the water and discharging the pollutant into the receiving tank. The scoop assembly including a scoop portion is hingedly connected to the receiving tank to enable the scoop portion to float on the water surface for movement relative to and independently of the receiving tank. An adjustable buoy assembly is mounted on the scoop assembly for controlling the depth of the scoop portion with respect to the surface of the water, depending on the depth to which the pollutant has reached below the surface of the water. A separation assembly is mounted on the main vessel, being connected in fluid communication to the receiving tank. The separation assembly includes a primary separation unit adapted to separate the collected pollutant by gravity into a substantially-water component and a substantially-pollutant component and a secondary separation unit connected in fluid communication with the primary separation unit for receiving the substantially-pollutant component for physically separating the remaining water therefrom. The primary separator unit comprises a series of settling tanks and a selectively actuatable pump assembly which interconnects the receiving tank in fluid communication with the settling tanks for controlling the rate of flow or pollutant therebetween. The primary separation unit further includes a float valve assembly adapted to open when submerged in a liquid having a specific gravity approximately equal to that of pure water and adapted to close when submerged in a liquid which is less than approximately that of pure water. The float valve assembly includes manifold means for selectively discharging the separated substantially pure water from the settling tanks and for conveying the remaining substantially-pollutant component to the secondary separator unit. The secondary separator unit comprises a rotary separation device, such as a centrifuge, or the like, which acts to further separate the remaining water from the pollutant. A storage tank is connected in fluid communication to the rotary separation device for receiving the substantially water-free pollutant therefrom. The storage tank is equipped with a discharge pump assembly for delivering the stored water free pollutant, at a subsequent time, to a storage location remote from the vessel for later use.
Brief Description of the Drawings
FIG. 1 is a side elevation view partially cut away and partially in section of the pollution removal installation of the present invention, showing one form of scoop assembly;
FIG. 1A is an elevation view of the settling tanks at the invention.
FIG. 2 is a top plan view of the pollutant removal installation of the present invention;
FIG. 2A in a top plan view of an alternative pump assembly system similar to that in FIG. 2.
FIG. 3 is a transverse sectional view taken along the line 3--3 of FIG. 2;
FIG. 4 is a transverse sectional view taken along the line 4--4 of FIG. 2;
FIG. 5 is a transverse sectional view taken along the line 5--5 of FIG. 1;
FIG. 6 is a perspective view of one form of receiving tank which can be used in carrying out the present invention;
FIG. 7 is a perspective view of another form of receiving tank which can be used in carrying out the present invention;
FIG. 8 is a perspective view of another form of scoop assembly which can be used in carrying out the present invention;
FIG. 9 is a front elevation view of another embodiment of the pollution removing installation of the present invention showing another form of rigging for supporting the receiving tank of the present invention;
FIG. 10 is a transverse sectional view taken along line 10--10 of FIG. 9; and
FIG. 11 is a perspective view of another form of rigging which can be used in carrying out the present invention.
Description of the Preferred Embodiments
Referring now again to FIG. 1, there is illustrated, generally at 1, an installation in accordance with the present invention. There is shown at 2 a vessel equipped with a conventional engine 3 having a propeller 4 for propelling the vessel through water, the surface of which is indicated at 5. The vessel 2 may be equipped with a conventional steerage assembly as at 7, for directing the vessel through the water. The vessel may be of a newly constructed vessel specially designed to carry the necessary equipment to carry out the present invention, or it may be of a used vessel which is reconverted for mounting of such equipment. For example, one type of vessel which could be readily converted and be very suitable for use in carrying out the present invention would be a vessel normally referred to as an LCM, or landing craft medium, employed by all branches of U.S. military including the Coast Guard. Such a vessel has a relatively large deck area and can carry relatively large loads with comparatively less draft than other types of vessels. Of course, other types of vessel construction can be employed and will be obvious to those skilled in the art, depending upon the size of the vessel and the particular waters on which the vessel is to be used. In any event, use of the materials and components, to be referred to hereinafter, are to be constructed in accordance with the U.S. Coast Guard specifications and standards where applicable.
Referring now to FIGS. 1 and 2, a receiving tank 10 is mounted forwardly of the bow of the boat and has an articulated scoop assembly 12 pivotally connected to the front side thereof. The rear side of the receiving tank is mounted for upward and downward movement relative to the bow of the boat so that the receiving tank 10 may float independently of the vessel 2. In the form shown, flanges 14 and 15 project outwardly from the rear side of the receivng tank being slidably disposed within the recesses or slots 16 and 17 formed by bending back the opposite edges of a plate 18 mounted adjacent the bow end of the boat. Of course, other means of enabling the receiving tank to move relative to the bow will be obvious to those skilled in the art in order to carry out the present invention. For example, the receiving tank 10 may be mounted within a frame 19, as shown in FIG. 7 for sliding movement up and down therein. As shown in FIG. 6, the receiving tank 10 includes a slot or opening 20 for receiving pollutant therein. The slot 20 is disposed at the upper side of the receiving tank 10 and may extend from side to side thereof.
The scoop assembly 12 is provided in a two-piece construction including a scooping portion 24 adapted for selective positioning with respect to the surface of the water for effectively skimming the pollutant therefrom, while minimizing the quantity of water taken in with the pollutant, as will be described in more detail hereinafter. The scoop assembly further includes ramp portion 25 which extends upwardly into the opening 20 in the receiving tank 10. As best shown in FIGS. 3 and 6, the scooping portion 24 is pivotally connected to the ramp portion 25 by hinge connection so that the scooping portion 24 may pivot relative to the ramp portion 25. The scooping portion 24 and ramp portion 25 have upstanding side plates 27, 28, 29 and 30 respectively for directing the pollutant through the opening 20 into the receiving tank 10. As shown in FIG. 1, buoys 21 and 22 are mounted on the scooping portion 24 so that it will float in a level position on the surface of the water. The rear edge of the ramp portion 25 is pivotally connected, such as by a hinge 31, to the receiving tank 10 at the lower side of the opening 20 to enable the ramp portion 25 to pivot with respect to the receiving tank 10 to allow the scooping portion 24 to float at the surface of the water as the receiving tank 10 moves upwardly and downwardly with respect to the bow of the boat, depending upon the volume of pollutant contained therein. A flexible cover 33 is disposed in covering relation over the juncture between the scooping portion 24 and the ramp portion 25 to prevent leakage of the pollutant therebetween. The articulated scoop assembly 12 is primarily designed for use in waters which are not still. In FIG. 8 there is illustrated another form of scoop assembly 12A which comprises only an inclined ramp portion 20A. Thus, it is desirable to have some form of float control to control the level of the inlet end of the ramp portion 26A with respect to the surface of the water. A hinge 31A is attached to the ramp portion 26A for connection to the receiving tank 10 to allow the ramp portion 26A to pivot relative to the settling tank 10.
Referring now specifically to FIGS. 1 and 2, a series of settling tanks 35, 36 and 37 are mounted on the vessel 2 which function as a primary separation unit. A pumping unit 38 is mounted on the vessel having its intake end connected through a flexible conduit 40 and its outlet end connected to a distribution manifold 41. The conduit 40 is secured to and extends downwardly into the receiving tank 10 for drawing the pollutant therefrom. The distribution manifold includes a main conduit 42 having branch conduits 43, 44 and 45 extending therefrom. The branch conduits are connected in fluid communication to settling tanks at their top side for discharging the pollutant therein. Each of the branch conduits is equipped with a valve 46, 47 and 48 selectively shutting off the flow of pollutant to any one of the settling tanks, as desired.
Because the aforementioned pollutants will have a specific gravity less than water and are not readily combinable with water, the liquid in the settling tanks will tend to separate with the pollutants moving to the top and the water settling to the bottom. Float valves 50, 51 and 52 are mounted at the bottom of the settling tanks 35, 36 and 37, respectively, for being adapted to open for draining off the portion of the liquid in the settling tanks which is substantially pure water, and are adapted to close when the specific gravity of the remaining liquid is less than that of water. The float valves 50, 51 and 52 are each connected in fluid communication with a holding tank 54 by conduits 55, 56 and 57 respectively. Each of the conduits 55, 56 and 57 have valves 58, 59 and 60 for selectively closing off the flow of liquid from the settling tanks into the holding tank 54. A holding tank 54 may be equipped with a filtration unit, as well known in the art, for removing the pollutants which remain in the water which flows into the holding tank 26. The quality and character of the pollutants collected by the filter unit will determine whether or not such will be discarded or further processed.
A secondary separation unit 62 is provided to separate the remaining pollutant in the separation tanks after the initial removal of the substantially pure water component. As best shown in FIG. 2, the secondary separation unit includes a pair of centrifuges 63 and 64. The centrifuge 63 is connected by means of a manifold assembly 65 to the settling tanks 35, 36 and 37, such as by conduits 66, 67 and 68, respectively. In the form shown, the conduits 66, 67 and 68 each includes a valve 70, 71 and 72, respectively, for closing off the flow of pollutant therethrough. As shown, the conduits 66, 67 and 68 flow into a manifold conduit 69. An inlet conduit 73 connects the manifold conduit 69 to the input of the centrifuge 63, and another inlet conduit 74 connects the manifold conduit 69 to the centrifuge 64. Valves 75 and 76 are connected in the conduits 73 and 74, respectively, for controlling the flow of pollutant therethrough. Another conduit 77 is connected between the conduit 74 and the outlet of the centrifuge 63 having one end connected to the conduit 74 between the valve 76 and the inlet to the centrifuge 64. A valve 78 is connected in the conduit 77 for controlling the flow of fluid therethrough. A discharge conduit 79 is connected between the conduit 77 and a storage tank 80 having one end connected to the conduit 77 between the outlet of the centrifuge 63 and the valve 78. A valve 81 controls the flow through the conduit 79. Although all of the aforementioned valves are shown as being manually operable, such valves may be operated automatically in a manner well known in the art to automatically control the flow from the settling tanks 35, 36 and 37 into the centrifuges 63 and 64. In addition, all of the above valves may be electrically connected to switch assemblies in the valves 50, 51 and 52, as well known in the art to automatically operate the valves upon the closing and opening of the float valves 50, 51 and 52. By this arrangement, the centrifuges 63 and 64 can be operated in series of parallel, or even independently of one another. For example, when the valves 76 and 81 are closed and the remainder of the valves are open, the centrifuges will be connected for series operation. When the valve 78 is closed and the remainder of the valves are open, the centrifuges will be connected for parallel operation. When the valves 73 and 78 are closed and the remainder of the valves are open, the centrifuge 64 will be connected for independent operation, and when the valves 76 and 78 are closed and the remainder of the valves are open, the centrifuge 63 will be connected for independent operation. Thus, the centrifuges 63 and 64 may be interconnected to obtain the degree and quantity of separation required.
As shown in FIG. 1, and as stated previously, the outlet of the centrifuge 63 is connected to the storage tank 80 by the discharge conduit 79 for discharging substantially pure petroleum therein. Another discharge conduit 82 connects the outlet of the centrifuge 64 to the storage tank 80 for the same purpose. Further, each of the centrifuges includes another outlet for the discharge of substantially pure water. Conduits 83 and 84 are connected to such outlets for directing the water to the side of the vessel for discharge into the surrounding water.
A pump assembly 85 is mounted on the vessel having its intake end connected to a conduit 86 which extends into the holding tank 54 and its outlet end connected to another conduit 88 for drawing the substantially pure water from the holding tank 54 for discharge from the vessel. Another pump assembly 90 is mounted on the vessel having its intake end connected to a conduit 91 which extends into the storage tank 80 and its discharge end connected through a conduit 92 for drawing the substantially water-free pollutant away from the vessel 2. The conduit 92 may be of the flexible-type so as to facilitate manipulation thereof for connection to conduits or storage facilities external of the vessel, as required.
Referring again to FIG. 2, a bypass system may be provided by bypassing both of the centrifuges 63 and 64 when the pollutant is substantially pure petroleum and separation is not required In the form shown, the bypass system includes another pump assembly 87 to provide additional pumping pressure to pump the pollutant from the tanks 35, 36 and 37. More particularly, a bypass conduit 89 connects the inlet of the pump assembly 87 to the manifold contuit 69. A valve 94 is connected in the bypass conduit 89 to control the flow of pollutant therethrough. Another conduit 96 connects the outlet of the pump assembly 87 to the discharge conduit 79 on the discharge side of the valve 81. By this arrangement, when substantially pure petroleum is present in the settling tanks, the valve 94 is opened, and the valves 70, 73 and 81 are closed so that the pollutant will be pumped by the pump assembly 87 through the conduits 89, 96 and 79 directly into the storage tank 80, and thus, bypass the centrifuges 63 and 64. Of course, under certain conditions the pressure in the system resulting from gravity alone will be sufficient to discharge the substantially pure pollutant from the tanks 35, 36 and 37, and thus, the utilization of the pump 87 may not be required.
In the alternative arrangement shown in FIG. 2A, the pump assembly 87 is employed to provide additional pumping pressure to move the pollutant through the centrifuges 63 and 64. More particularly, the outlet conduit 96 of the pump assembly 87 may be connected into a secondary manifold conduit 69a. One end of the conduit 96a is connected to the conduit 73 on the outlet side of the valve 75 for distributing the pollutant through the inlet of the centrifuge 63. The opposite end of the conduit 69a is connected to the inlet of the centrifuge 64, A valve 75a is connected in the conduit 69a between the conduit 73 and the junction of the conduit 69a and 96. Another valve 76a is connected in the conduit 69a between the inlet of the centrifuge 64 and the junction of the conduits 69a and 96. Further, a series conduit 96a connects the outlet of the centrifuge 63 on the outlet side of the valve 76a to transmit the pollutant between the centrifuges 63 and 64. A discharge conduit 79a is connected into the conduit 96a for discharging the pollutant from the centrifuge 63 into the storage tank 80. The valve 78 is connected in the conduit 96 between the conduits 69a and the junction of the conduit 79a and 96a for shutting off the flow through the conduit 96a. A valve 81b is connected in the conduit 79a to shut off the flow of pollutant to the storage tank 80. By this arrangement, when the valve 75 and 76 are closed, and the valve 94 is opened, the pollutant will flow from the manifold conduit 69 through the conduit 89 to the pump assembly 87. By closing the valve 81 and opening the valve 81a, the pollutant can be pumped direct to the storage tank 80. On the other hand, when it is desired to pump the pollutant to the centrifuges 63 and 64 for parallel separation, the valve 81a is closed, and the valve 81 is open, so that the pollutant can be pumped to the conduit 69a. When the valves 75a and 76a are opened, the pollutant will flow to both of the centrifuges 63 and 64 for discharge to the storage tank 80 through the discharge conduits 79a and 82 respectively. On the other hand, when the valves 76a and 81b are closed, and the valve 78 is opened, the centrifuges 63 and 64 will be connected in series, and the pollutant will flow into the centrifuges 63, then to the conduit 96a to the centrifuges 64 from which it will be discharged to the storage tank 80 to the conduit 82. The system shown in FIG. 2A will operate similar to that shown in FIG. 2 when the pump assembly 87 is disconnected from the system by closing the valve 94 so that the centrifuges 63 and 64 can be operated independently in series or parallel.
In another modification of the present invention shown in FIG. 1a, all of the settling tanks 35, 36 and 37 may be atmospherically sealed and have their air vents, such as 95, connected to a common vent manifold 95a to allow the transfer of air therebetween. Each of the tank vents 95 may be equipped with a valve 95b, which may be manually or automatically operated, as desired, to selectively close off any one of the vents 95, and therefore, enable the air from any one or more tanks to be transferred to any one or more of the other tanks. Pressure relief valves 95b should be provided for each of the settling tanks 35, 36 and 37 in the event that the pressure in the tanks exceeds a predetermined maximum magnitude. As can be seen, in a typical operation of the aforedescribed modification, a pollutant may be pumped from the receiving tank into one of the tanks, for example, the settling tank 35, when the vent valve 95b of the settling tank 37 is closed. When the valve 70 and 72 are closed, the air from the tank 35 will be forced into the common vent manifold 95a, and then into the settling tank 36 to force the pollutant therein from the tank 36 to the centrifuges 63 and 64. Of course, it is understood that any combination of the valves may be opened and closed to obtain flow from any one or more tanks to any one or more of the other tanks. By this arrangement, additional pressure may be provided in the system by the pump 38 to supplement the pressure provided by the gravity flow operation or to supplement the pump assembly 87 when such is connected in the system.
The vessel is arranged so as to be self-contained and includes a power unit 93 in the form of a diesel engine-generating unit 93a for supplying the electrical power requirements of the vessel. An air compressor 93b is provided to provide the compressed air requirements of the vessel wherever required. Although it is not shown in every instance all of the aforementioned tanks should be equipped with suitable vents, such as at 95, to enable the tanks to be vented of any toxic or explosive fumes or gasses which may accumulate in the tanks during the recovery process. In addition, all of the tanks should be equipped with access doors or covers (not shown) to enable cleaning thereof.
Referring now to FIG. 4, the buoys 21 and 22 are provided in the form of air tanks which are generally cylindrical in transverse cross section. As shown, each of the tanks is formed to have an upper section 97 and lower section 98. In the form shown, the sections 97 and 98 are generally semi-circular in transverse cross section, having a flexible diaphragm 99 disposed therebetween and held in position by suitable fasteners, such as at 100 and 101. As further shown, a lower section 97 is provided with an inlet opening 103 for receiving water therein, whereas the upper section 97 is equipped with an inlet opening 104 which is connected to the output of the compressor 93b by a conduit 105 for receiving compressed air thereform. A selectively-actuatable valve assembly (not shown) as well known in the art may be connected between the compressor 93b and the inlet 104 for controlling the flow of compressed air into the tank 22. With this arrangement, the tank 22 may be evacuated or filled with compressed air as desired for controlling the quantity of water flowing into and out of the inlet 103 for controlling the level of the tank 22 in the water, and thus the position of the leading end of the scopping portion 24 with respect to the water level. This is of importance in that the depth of the pollutant with respect to the water surface will vary depending upon the form of the pollutant and the period of time which the pollutant has been in the water. It has been found that the pollutant will vary in depth from the surface in a range from a fraction of an inch to 3 or 4 inches. By selectively controlling the depth of the scoop member, and efficient method is provided for minimizing the quantity of pure water taken in with the pollutant during the scooping process.
Referring now to FIG. 5, the float valves, such as at 50, are preferably of the ball-type and include a base 106 which is secured to the bottom wall, such as at 107, of the settling tanks, such as 35, in any suitable manner, such as by welding or the like. The base 106 includes a central orifice 109 which is connected in fluid communication to the discharge conduit, such as 55. The orifice 109 is preferably circular in transverse section, having its upper marginal edges providing a seat for receiving a ball 108 in seated engagement therewith. A frame 110 is mounted over the orifice 107 and supports a screen 111 to enable the free flow of the liquid in the settling tank through the screen and into the discharge conduit 55 and containing the ball 108. The ball 108 is weighted and sized such that it will float in a liquid material having a specific gravity of approximately that of water, whereas it will not float in a liquid having a specific gravity which is less than that approximately equal to the specific gravity of water. By this arrangement, the valve will open when the ball 108 is submerged in substantially pure water and will close when the substantially pure water has been drained from the settling tank and a substantially petroleum base liquid remains.
In the event that the present invention is modified in accordance with the arrangement shown in FIG. 1A, the ball float valves 50, 51 and 52 may not necessarily operate effectively, and thus, such ball float valves may be either modified to include mechanical locking arrangements so as to selectively prevent their opening, or mechanically operative valves may be substituted therefor which may be operated in conjunction with the settling tank vent valve 95b. As the solution which will be passing from the receiving tank 10 through the pump 38 and into the settling tanks 35, 36 and 37, may be well mixed, the modification of the float valves or the substitution of the mechanical valves is considered advisable to avoid the contamination of the system for discharging substantially pure water from the settling tanks and to assure that the outlet valves 50, 51 and 52, of the settling tanks 35, 36 and 37 are in a closed position until the tanks are ready for processing.
Referring now to FIGS. 9 and 10, there is shown still another embodiment of the present invention. In this form, multiple receiving tanks 10a are utilized in collecting the pollutant. As shown in FIG. 9, each of the receiving tanks 10a is supported outwardly from the vessel 2 by a boom 115 which is pivotally connected at its inner end to a vessel 2 and projects outwardly therefrom. A pulley 117 is supported adjacent the opposite outer end of each boom 115 which in turn support a cable 118. Each cable 118 is attached at one end to the receiving tank 10a and has its other end operably connected to a suitable winch mechanism 120 for selectively raising and lowering the receiving tank 10a into and out of the water. In this form of the invention, each receiving tank 10a may be equipped with a scoop assembly 12b which is rigidly mounted thereon. Buoys 122 in the form of air tanks similar to the air tanks 21 and 22 described above, may be mounted on the opposite sides of the receiving tanks 10a for selectively controlling the level of the leading edge of the scoop assembly 12b with respect to the surface of the water. In addition, the receiving tanks 10a may be formed with a receiving chamber 123 adjacent the upper end into which the pollutant flows as it enters the receiving tank 10a. A dividing wall 124 may be rigidly secured within the receiving tank forming an air chamber 126 below the receiving chamber 123. An inlet opening 125 is provided in the air chamber 124 to enable water to flow into an out of the air chamber 124. An air line 127, supplied with pressurized air from the compressor 94, is connected in fluid communication to the air chamber 124 for purging the water from the chamber 124 to provide further control for adjusting the level of the receiving chamber 10a in the water in response to the guantity of pollutant contained in the receiving chamber 123. Of course, it would be apparent to one skilled in the art that the receiving chamber 10 described in FIGS. 1 and 2 having an articulated scoop assembly 12 could also be readily adapted and substituted for the receiving chamber 10a in the embodiment shown in FIG. 9.
Referring now to FIG. 11, there is shown another arrangement for supporting multiple receiving tanks, such as 10c, on a vessel 2. In the form shown, a framework 133 is provided which includes a generally horizontal extending arm 132 and an angularly upwardly extending arm 133. The inner ends of the arms 132 and 133 are connected together by a plate 134 which is mounted on the side of the vessel 2. A brace 134 extends between the arms 132 and 133 and supports the outer ends in spaced relation from one another. Slide blocks 135 and 136 are supported at the outer ends of the arms 133 and 132 respectively, for supporting an elongated, generally vertically-oriented column 137. More specifically, the slide blocks 135 and 136 have openings 139 and 140 which are axially aligned in the vertical direction for slidably receiving the column 137 therein. A lower end of the column 137 is connected to the top side of a receiving tank 10a. By this arrangement, the receiving tank 10a is free to float in the water alongside of the vessel 2 with the column 137 sliding up and down in the sliding blocks 135 and 136.