Abstract:
An oil skimmer of the endless belt type is disclosed. The unit has an adjustment for adjusting the location of the axis of head pulley rotation and a floating tail pulley to assure accurate tracking of the belts on the pulleys. The tail pulley features L-shaped spokes having legs that provide limited pulley-to-belt contact, minimizing oil transfer from the belt to the tail pulley, and also providing a mechanism for forcing oil against a descending belt reach to provide enhanced oil pick-up. The tail pulley is provided with a catch frame and an anchored tether for catching the belt and the tail pulley in the event that the belt breaks.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to U.S. Patent Application Ser. No. 07/950,802 filed on Sep. 24, 1992 titled Oil Skimmer and Method of Operation. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus for separating oil from water. and more particularly, to an oil skimmer assembly which has an endless belt for removing oil from the surface of water. 
     2. Description of Related Art 
     With oil skimmers utilizing endless belts, typically, the belt :is suspended from a driven head pulley. The belt is also passed around a tail pulley that is positioned in a body of water. When the head pulley is rotatably driven, a descending reach of the belt on entering the body of water will pick up surface oil and carry that oil around the tail pulley to an ascending reach of the belt. Wipers are positioned below of the head pulley near the top of the descending reach to scrape oil from the surface of the belt. Collection pans positioned below the wipers receive the separated oil and deliver the separated oil to a collection vessel for recycling or appropriate disposal. 
     In the past, the tail pulleys have usually either been mounted in a vessel containing the oil and water to be separated or alternately, supported exclusively by the belt. As an example of the latter, if oil is to be removed from a contaminated water well, an elongated belt supporting a tail pulley is dropped into the well, and the weight of the pulley and the belt provide belt tension. Clearly, if the belt breaks, there is a problem because the pulley will be dropped into the well and either lost or, at best, retrievable only through a successful &#34;fishing&#34; operation. Even if the belt does not break, on occasion, a pulley will slip out of the belt as the belt is lowered or during operation, and once again, an operator has, at best, a difficult retrieval process to confront. 
     Even where tail pulleys are not rotatably mounted in tanks but are supported by the belt, other problems manifest themselves. If the axis of rotation of the head pulley is not properly oriented, the belt will not track properly and excessive wear can occur. If the belt is steel, the wear is exacerbated and considerable damage can be caused to both the belt and the head pulley. Further, if the head pulley is equipped with magnets to drive the belt, a misaligned magnet or protruding magnet can cause excessive belt tension that results in belt failure. 
     Another problem is that when endless belt oil skimmers are used in quiescent bodies of water, their efficiencies can be relatively poor. The relatively poor efficiency is due to the fact that the belt picks up oil as it enters a water body and if the body is quiescent, the surface in the vicinity of belt entry soon becomes relatively oil free. Further, pick-up must wait for a relatively slow from portions of the body surface remote from the belt entry migration of oil location. 
     SUMMARY OF THE INVENTION 
     An oil skimmer made in accordance with the present invention overcomes the above shortcomings and provides the operator with ease of retrieval in the event of belt breakage, belt tracking adjustment and efficient oil pick-up capability. Basically, the oil skimmer has a frame including a motor support section near the top of the frame when the skimmer is in use. A motor is carried by the support and includes an output shaft. A head pulley is drivingly connected to the shaft. An endless belt is drivingly supported in engagement with the head . A tail pulley is floatingly supported by the belt and adapted to be immersed in a liquid volume when the skimmer is in use. The tail pulley has a shaft and a frame connected to the shaft. The frame has a has a support member adapted to catch the belt in the event that the belt breaks. The frame member has member for connecting to a tether. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are shown in the accompanying drawings in which: 
     FIG. 1 is a perspective view showing the improved oil skimmer of the present invention; 
     FIG. 2 is a perspective view of the tail pulley of the oil skimmer of FIG. 1; 
     FIG. 3 is a front elevation view of an alternate embodiment of the tail pulley of FIG. 2; 
     FIG. 4 is a top plan view of the tail pulley of FIG. 2; 
     FIG. 5 is a front elevation view as seen approximately from the plane indicated by the lines 5--5 in FIG. 4; 
     FIG. 6 is a side elevation view as seen approximately from the plane indicated by the lines 6--6 of FIG. 5; and 
     FIG. 7 is a fragmentary side elevation view of a top portion of the oil skimmer. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, an oil skimmer embodying the present invention is shown generally at 10. The oil skimmer 10 is mounted above a body of fluid (not shown) and operated to remove surface oil from the fluid. 
     The oil skimmer 10 includes a frame 12 which is mounted on a stationary support 14. A motor 16 is connected to a reduction gear box 18. The gear box is secured to a support section located near a top of the frame 12. 
     A head pulley 20 is mounted on the output shaft 22 of the gear box 18 The head pulley 20 includes inner and outer side flanges 24, 28 which are in the preferred embodiment, connected together in spaced relationship by a set of spaced L-shaped spokes 30. As is best seen in FIG. 1, each of the head pulley spokes is L-shaped in cross section with arms 32 being disposed radially and legs 34 projecting orthogonally from the arms 32 at the inner ends of the arms. 
     A set of magnets 36 is provided. Each magnet is mounted in axially spaced relationship on one of the spoke arms 32 with the spoke legs 34 serving to support the magnets. The magnets 36 have outer surfaces disposed in an imaginary cylinder which is coaxial with the shaft 22 in order that the magnets drivingly engage an endless belt 38 which, in the disclosed embodiment, is steel. 
     As seen in FIG. 7, the motor 16 and head pulley 20 and frame element 12 are mounted on a hinge 84 for adjusting the angle of the head pulley shaft 22. A pair of adjusting bolts 86 join the frame element 12 to the frame including a support section in the form of a stationary support and clamp structure 88. Springs 92 are placed around the bolts 86 to urge the frame upwardly against the heads of the bolts 86. Tightening or loosening of the bolts 86 tilts the frame and motor and shaft 22 with respect to the stationary clamping structure 88. This permits adjustment of the belt tracking on the head pulley 20. 
     A tail pulley 40 is provided and is positioned at least partially in the body of fluid when the device is in use. The tail pulley 40 includes a shaft 42. A belt-retainer frame 44 is connected to the shaft 42. The frame 44 includes two squared U-shaped belt retainer members 46, 48 which project oppositely from a shaft mounted support bracket 49 to surround the tail pulley 40 and the belt 38. The belt retainer members 46, 48 extend radially from locations near the ends of the shaft 42 and lie in a plane which includes the axis of the tail pulley 40. The shaft 42 is rotatably connected to the brackets 49 such that the tail pulley 40 may rotate with respect to the frame 44. 
     A semi-circular, preferably fabric, catch pad 50 is connected at each end to one of the U-shaped member 46, 48 and generally coaxially surrounds the lower half of the tail pulley 44. As seen in FIG. 5, the catch member has a transverse width dimension W extending in a direction parallel to the axis of rotation of the tail pulley that is less than the axial width of the tail pulley. The catch pad 50 and the belt retainer members 46, 48 serve to catch and retain the steel belt 38 in the event that it breaks and falls from the head pulley 20. A connecting member 52 is also joined to the frame 44 and extends upwardly at approximately 90° from the rectangular members 46,48. The connecting member 52 is adapted to be attached to one end of a flexible tether 54 which is preferably anchored at its other end to a stationary member outside of the fluid. The tether is preferably a chain which serves to support the retainer frame 44 and the tail pulley 40 when they are lowered onto or removed from a body of fluid and also in the event of a belt breakage. 
     The preferred tail pulley 40 is shown in FIG. 1. The preferred tail pulley, like the head pulley, has spaced inner and outer annular flanges 56, 58. The inner and outer flanges 56, 58 are interconnected by a drum 100, or more preferably, a circumferentially spaced set of L-shaped spokes 60. Arms 62 of the spokes 60, like the arms 32 of the head pulley spokes 30, are radially disposed. In contrast to the head pulley 20, legs 64 of the tail pulley spokes 60 project orthogonally from the arms 62 at the radially outward ends of the arms. The legs 64 project from the arms 62 in the direction of pulley rotation as indicated by arrow 66, FIG. 1. The arms 62 have outer surfaces disposed in an imaginary cylinder that is coaxial with the shaft 42 and are sequentially in driven engagement with the belt 38. The tail pulleys illustrated in FIGS. 2-6 for simplicity of illustration are shown as having conventional cylindrical drums between the flanges rather than spokes. 
     In a second embodiment illustrated in FIG. 3, a pair of tail pulley 40 are joined together in a side-by-side axially aligned configuration and may share a common shaft. Each pulley has retainer members 46, 48 and catch members 50 as in the single-pulley embodiment. A single connecting member 90 is connected to the retaining flames and serves the same purpose as the connecting member 52 previously described. 
     OPERATION 
     In use, the oil skimmer 10 is mounted above the body of fluid from which oil is to be removed. The tail pulley 44 and the lower portion of the belt 38 are then lowered until they are submersed in the fluid. As the pulley and belt are lowered by using the tether 54, the retainer frame 44 functions to prevent the tail pulley from slipping out of the belt and dropping into the body of fluid. 
     Once the belt and tail pulleys are properly positioned in the fluid, the motor 16 is energized to cause the head pulley 20 to rotate. Through the engagement of magnets 36, the steel belt 38 is driven such that a descending 68 descends into the body of liquid. As the descending reach 68 enters the fluid, assuming there is oil on the surface of the fluid, the oil will adhere to both inner and outer faces of the belt 38. The belt then passes around the tail pulley 40. Due to the use of the spokes 60 rather than a cylindrical surface, transfer of oil from the inner surface of the belt 38 to the tail pulley is minimized. 
     An ascending reach 70 of the belt 38 carries the oil upwardly to and over the head pulley 20. At a location near the top of the descending reach 68, inner and outer wipers 72, 74, of conventional construction, engage the descending reach 68 and wipe the oil from it. The wiped oil is caught by a collection vessel 76 and thence discharged through a discharge port 78 for suitable recycling or disposal. 
     As the operation continues, appropriate tension is maintained on the belt 38 through the weight of the belt itself and the tail pulley 40 and frame 44. Thus, the tail pulley 40 is free to float and is supported by the belt. 
     Should there be a problem with the belt 38 tracking off center with respect to the head pulley 20, adjustment is accomplished by loosening or tightening the adjustment bolts 86 until the belt 38 is tracking properly between, and without engaging, the inner and outer flanges 24, 28. 
     The tail pulley spokes 60 provide one of the outstanding features of the invention. That is, that the L-shaped spokes 60 tend to agitate the fluid. Ideally, the tail pulley 40 is only partially submerged so that the spokes 60 will break the surface as they approach the maximum height. Since the spokes 60 are L-shaped with their legs 64 projecting orthogonally in the direction of rotation, the spokes 60 tend to trap surface oil and push the surface oil toward the descending reach 68 to enhance the oil pick-up efficiency of the belt 38. 
     Upon completion of an oil removal operation, or in the event of belt breakage, the tail pulley, the belt and the belt retainer are retrieved from the body of fluid by lifting them with the tether. 
     While a preferred embodiment of this invention has been described in detail, it will be apparent that certain modifications or alterations can be made without departing from the spirit and scope of the invention set forth in the appended claims.