fig1 represents in schematic form a sectional elevational view of one particular embodiment of the invention . in this view , a floating pumping system 10 is shown installed within a groundwater recovery well 12 . the well includes a slotted casing 14 which allows the free flow of groundwater and floating product into the well 12 . the system 10 comprises a main , body 16 in the form of a hollow cylinder 17 which has a diametrical plug 18 at its lower end . the cylinder 17 has side openings 15 bridging the water surface which allow water and floating product into the cylinder 17 . an air cylinder 20 operating as a linear actuator is mounted to the plug 18 by a threaded coupling 19 . the cylinder 20 has a movable rod 22 , to which is attached a right circular cylindrical member 24 which is open at the top and closed at the bottom by a cone - shaped portion 26 . this may perhaps be better seen in the schematic view of fig2 . in the view of fig1 the rod 22 is shown in the retracted position . within the upper portion of the body 16 is a transverse sealing plate 28 which closes off the upper open end of the body 16 . this plate 28 provides a sealing surface for the upper end wall of the cylindrical member 24 and also has a central sealing portion 30 for mating with the upper end of the cone - shaped element 26 . the sealing plate 28 has an inlet port 32 for the attachment of an air inlet tube 34 and an exit port 36 for the attachment of a floating product tube 38 through which captured floating product is driven to exit the system 10 . the discharge tube 38 extends to a holding tank or reservoir ( not shown ) which may be emptied periodically as needed for disposal of the contamination product . mounted in the exit port 36 is a check valve 40 to prevent any reentry of floating product which is forced out through the tube 38 . the system is provided with a suspension link 44 to which a cable 46 is connected . at the lower end , mounted on the air cylinder 20 , is a buoyancy collar 50 . mounted to the lower end of the cylinder 20 is another link 52 from which a weight 54 is suspended . air tubes 60 , 62 are connected to ports 64 , 66 in the air cylinder 20 to control the actuation of the air cylinder 20 . a pickup tube 37 extends downwardly from the exit port 36 into the space around the periphery of the cone 26 where the floating product / effluent which has been captured by the cone 26 is gathered before being driven out of the system . the cylinder 24 with its cone - shaped bottom 26 is shown in two different positions in fig1 corresponding to the upper and lower limits of travel for this element . the lower position is indicated in phantom outline . the operation of the system 10 of fig1 may be explained in conjunction with the schematic diagram of fig2 wherein the cylinder 24 with its cone - shaped bottom 26 is shown between the upper and lower limit positions depicted in fig1 . referring to fig2 the cone - shaped bottom 26 may be viewed as an inverted funnel having a central , downwardly extending shaft 23 which is attached to the movable rod of the pneumatic actuator 20 . at the upper end of the inverted funnel 26 is a plurality of apertures or small ports 68 which communicate between the inner space 70 of the inverted funnel ( cone - shaped bottom 26 ) and the collection space 72 outside the bottom 26 . the ports 68 extend through a portion 74 which is provided with a sealing surface 76 shaped to mate with a corresponding sealing surface 78 on the sealing member 30 . an air source and controller stage 25 is coupled to control the pneumatic actuator 20 . similarly , a pressure source 80 with controller 81 is connected to the inlet port of the transverse sealing plate 28 to control the removal of collected floating product from the system . as the cylinder 24 is driven toward its lowermost position by the pneumatic actuator 20 , it submerges through the surface of the groundwater in the well 12 , at the same time trapping any floating product which is floating on the surface within the area encompassed by the cylinder 24 . as the cylinder 24 moves below the surface , the trapped floating product is driven upwardly through the apertures 68 , being forced from the space 70 into the space 72 . the force which drives the floating product from the space 70 to the space 72 is the head pressure of the groundwater above the exit plane of the cone 26 . this collected product is now contained within the right cylinder 24 in the space 72 outside the cone 26 . the cylinder 24 is now driven to its uppermost position by the pneumatic actuator 20 where the surface 76 of the cone 26 is driven into sealing engagement with the surface 78 of the sealing member 30 . at the same time , the upper end wall 82 of the cylinder 24 is driven into sealing engagement with the lower side 84 of the sealing plate 28 . the pressure source 80 is then activated to drive air into the space 72 which is now sealed closed against the sealing plate 28 and protruding seal member 30 . the increased air pressure within the space 72 drives the trapped floating product out through the pickup tube 37 , the check valve 40 and discharge tube 38 . after a pre - set time in the upper position , the cylinder 24 is driven downwardly again by the pneumatic actuator 20 to begin a new cycle . the discharge cycle , during which the pressure source 80 is actuated to drive air into the space 72 when that space is sealed closed in the uppermost position of the cylinder 24 , may occur after every cycle of the cone being retracted and extended , if desired . however , many remedial sites have only a thin film of product floating on the groundwater , and the product discharge may only be required after several cycles of the cone 26 being retracted and extended . the controller 81 coupled to the pressure source 80 may accomplish this by use of a predetermined cycle counter or by any other appropriate means . for example , a sensor 86 may be suspended from the transverse plate 28 to detect collected product within the space 72 when it has reached a level where it should be discharged , thus triggering the controller 81 to actuate the pressure source 80 to pressurize the space 72 . fig3 is a schematic , sectional view , similar to that of fig1 and 2 , of a second particular arrangement in accordance with the present invention . the system 100 of fig3 incorporates the body 16 and related components of the system 10 of fig1 and 2 in combination with a hydraulic pump 110 and a double acting linear actuator 120 . like elements of the arrangement of fig1 and 2 which are incorporated in the arrangement of fig3 are designated by like reference numerals . the air cylinder 120 is essentially like the cylinder 20 of fig1 except that it is double acting via a second drive rod 122 which protrudes out the lower end in line with the upper drive rod 22 . the cylinder 120 is actuated by the air lines 60 , 62 as in fig3 . the buoyancy collar 50 has been omitted for simplicity . the hydraulic pump 110 is mounted to the air cylinder 120 and suspended therefrom by means of a threaded coupling 112 . the hydraulic pump 110 comprises a cylinder 114 closed at the upper end by end plate 116 and at the lower end by end plate 118 . each of the end plates 116 , 118 is provided with a pair of fluid ports extending therethrough to communicate with the adjacent inner portion of the pump . the cylinder 114 is divided into an upper space 130 and a lower space 132 by a rolling diaphragm 134 which is secured between flanges 136 about the wall of the cylinder 114 and held between a pair of piston plates 138 that are secured to the lower end of the rod 122 by means of a clamping nut 140 . thus , as the cylinder body 24 and cone 26 of the system 10 are driven between upper and lower positions by the air cylinder 120 , the rolling diaphragm 134 between piston plates 138 at the end of rod 122 is driven in like fashion between upper and lower positions within the cylinder 114 . as with the cylinder 24 and the cone 26 , the lower position of the roller diaphragm 134 and associated parts is shown in phantom outline . the lower end plate 118 of the cylinder 114 has an inlet port 124 and an outlet port 125 , each including a check valve 126 to control the direction of flow therethrough . the upper end plate 116 is provided with an inlet port 127 and an outlet port 128 . the inlet port 127 is provided with a check valve 126 to control the direction of water flow therethrough . a shuttle valve 140 is coupled to the exit port 128 of the upper plate 116 and acts as a check valve for the port 128 to permit the flow of water through the exit port 128 in the outward direction only . the shuttle valve 140 is provided with inlet openings 142 , 143 at the lower and upper ends thereof , respectively , and an outlet opening 144 in the middle . depending upon operating pressures at the inlet openings 142 , 143 , the shuttle valve alternatively provides a communicating passage from one or the other of the inlet ports 142 , 143 to the outlet port 144 . a tube 146 connects the exit port 125 in the lower end plate 118 with the inlet opening 143 of the shuttle valve 140 . another tube 148 connects the outlet port 144 with a collection reservoir above the groundwater surface , preferably outside of well 12 . the hydraulic pump 110 operates as follows in conjunction with the operation of the floating product collection system 10 . as the rod 22 / 122 moves downwardly , driven by the actuator cylinder 120 , the rolling diaphragm 134 compresses the space 132 and expands the space 130 . as the space 130 expands , water is sucked in through the now - open check valve 126 in the inlet port 127 in the upper end plate 116 . at this point , the shuttle valve 140 is in a position which blocks flow through the port 128 . compression of the space 132 forces the check valve 126 in the port 124 closed and drives water which is collected within the space 132 outwardly through the port 125 , through the tube 146 to the inlet port 143 of the shuttle valve 140 . at this point , the shuttle valve is in the position to provide a passage between the inlet port 143 and the outlet port 144 so that water is driven outwardly to the surface through tube 148 from the lower chamber 132 in the hydraulic pump 110 . on the upward stroke of the air cylinder shaft 22 / 122 , water is now driven out of the upper chamber 130 through the exit port 128 and a now - open passage within the shuttle valve 140 to the outlet port 144 where it exits through tube 148 to the surface . during this movement of the piston plates 138 and rolling diaphragm 134 , the check valve 126 within the port 127 closes , as does the check valve 126 within the lower inlet port 125 . at the same time the check valve 126 within the inlet port 124 of the lower end plate 118 opens so that water can be drawn into the expanding volume 132 . the cycle is repeated for each up and down stroke of the rod 22 / 122 . in this manner , water is pumped out of the well 12 as the floating product is collected and driven upwardly through the openings at the top of the cone 26 of the system 10 , thereby creating the desired cone of depression so that water flows into the well 12 , drawing the floating product with it for collection and removal by the system 10 . the preferred embodiments of the disclosed invention have been shown and described in the context of a recovery device for use in groundwater wells . however , systems in accordance with the present invention may also be used to recover product in other bodies of water contaminated with floating product such as , for example , barge berths , lagoons and sumps . this device can very readily be sized to accommodate various specific requirements . systems in accordance with the present invention are simple in construction , economical to manufacture , and are provided in a rugged design to be essentially maintenance free for long periods of time . although devices of the present invention may superficially resemble in - well pump skimmers of the prior art , it will be recognized the principle of positive collection and withdrawal of floating product from the surface of the groundwater or other water which is involved make the devices completely unlike conventional skimmers . although there have been described hereinabove various specific arrangements of a hydraulic separator pump in accordance with the invention for the purpose of illustrating the manner in which the invention may be used to advantage , it will be appreciated that the invention is not limited thereto . accordingly , any and all modifications , variations or equivalent arrangements which may occur to those skilled in the art should be considered to be within the scope of the invention as defined in the annexed claims .