text: the filter device shown in fig1 , especially a reversible flow filter device , has a cylindrical housing 10 including of a top housing part 12 and a bottom housing part 14 . the two housing parts 12 , 14 can be detachably connected to each other via a detachable bracket clip 16 ( compare fig2 ). the housing 10 can be attached to other components , for example , those of a hydraulic type , at the bottom housing part 14 by flange - shaped fastening parts 18 . the filter housing 10 of the reversible flow filter device has a filter inlet 20 for the fluid to be filtered and a filter outlet 22 for the filtered fluid . within the bottom housing part 14 , diametrically opposite to the filter inlet 20 relative to longitudinal axis 24 , a fluid outlet 26 is provided via which a quantity of backflushing liquid can be withdrawn from the device . filter elements 28 tapering conically to the top are inserted into the filter device . at least partially cylindrical filter elements ( not shown ) are able to replace the conical filter elements 28 . the conical filter elements 28 of wedge - wire screen filter elements are configured at distances from each other along a cylindrical arc ( compare fig3 ) within the filter housing 10 . in an embodiment ( not shown ), the filter elements 28 can also be configured repeatedly divided into groups along cylindrical arcs . for the embodiment shown in the figures however a total of four filter elements 28 are diametrically opposite each other viewed toward the longitudinal axis 24 of the device . viewed in the direction of fig3 , the top filter element 28 is shown in its backflushing position , and the filter elements 28 located underneath are in their filtration positions . by a pivoting device 30 , the individual filter elements 28 can be moved in succession from their filtration positions into the backflushing position and back into the filtration positions . the rotary motion can take place both clockwise and counterclockwise for the individual filter elements 28 . the pivoting device 30 itself has a receiving element 32 for holding the individual filter elements 28 . the receiving element 32 is pivotably mounted within the filter housing 10 for rotation around a pivoting axis 36 by a drive or motor 34 . this pivoting axis 36 is essentially congruent with the longitudinal axis 24 of the filter device . the receiving element 32 has two opposing end parts 38 , 40 between which the individual filter elements 28 extend . at least the end part 40 facing the filter inlet 20 is guided along the interior of the filter housing 10 via a sealing means or seal 42 . the respective end part 38 , 40 is designed as a cylindrical plate . the lower end part 40 on the outer peripheral side has recesses for holding the sealing parts of the sealing means or seal 42 . in this way , a sliding seal is attained between the interior of the filter housing 10 and the outer periphery of the lower end part 40 . as is to be seen especially from fig3 , the lower end part 40 has a kidney - shaped recess 44 which can be supplied with fluid from the filter inlet 20 . as long as the three filter elements 28 with their lower free opening cross sections 46 as shown in fig3 are located over the kidney - shaped or arcuate recess 44 , the fluid to be filtered flows via the filter inlet 20 and the recess 44 as well as the lower opening cross section 46 into the interior of the respective filter element 28 . for this purpose , fluid flows through the filter elements 28 from the inside to the outside . dirt present in the fluid is deposited on the inner wall of the respective hollow filter element . the filter element 28 which is the upper one when viewed in the direction of fig3 is removed therefrom . the filtrate or clean fluid present in the filter housing is routed in the reverse direction , that is , from the outside to the inside , through the upper filter element 28 to be cleaned out since the exterior of each filter element is in fluid communication , as shown . the fluid dirt removed and obtained in this way travels out of the interior of the filter element 28 being backflushed , and in turn flows via its lower free opening cross section 46 in the direction of the fluid outlet 26 , and accordingly , out of the device . for the transport of the backflushing fluid , the lower end part 40 has a circular through opening 48 . on the opposing or top end , the individual filter elements 28 are closed , and held in the upper end part 38 having individual recesses 50 engaging or receiving the upper free ends of the filter elements 28 . the two end parts 38 , 40 are detachably connected to each other along the pivoting axis 26 via a rod - like drive part 52 . with the upper cover part 12 removed and the two end parts 38 , 40 released from each other , a used filter element 28 can be replaced with a new element in the event this should become necessary . the drive part 52 can be driven by the drive 34 of the filter device designed in particular as a pneumatic motor . this pneumatic motor has a journal - shaped driven part 54 . depending on the pump motion of the piston parts of the pneumatic motor , as a drive 34 executes alternating back and forth motion , the pertinent back and forth motion then can be converted by a free - wheeling device or free wheel device 56 into a constant drive motion in one driving direction for the drive part 52 of the receiving element 32 . the free - wheeling means 56 is especially a free - wheeling sleeve 56 a which with its movable components couples the driven part 54 to the drive part 52 . for this coupling , the rod - like drive part 52 viewed in the direction of fig1 on its bottom is coupled to a drive axle 58 guided to turn or pivot in the lower housing part 14 . this free - wheeling sleeve 56 a of the free - wheeling device 56 is able to relay the alternating back and forth motion of the drive 34 in only one direction to the drive line of the pivoting device 30 including of the driven part 54 , the drive axle 58 and the drive part 52 . in the other direction , the free - wheeling device 56 does not transmit any torque to the drive line . the free - wheeling sleeve used with an inner star and individually sprung rollers is prior art , and is especially suitable due to its low slip as far as entrainment of the drive axle 58 . for the opposite rotary motion for the free - wheeling sleeve , a moment is not delivered to the device or consequently to the drive line . these free - wheeling sleeves and free - wheeling devices 56 are prior art so that they will not be described in detail . the drive axle 58 can also be made in several parts to ensure interchangeability of parts of the axle when wear occurs . with this drive , alternative back and forth motion of the pneumatic motor as a drive 34 can be converted into pivoting motion by 90 ° at a time for the filter elements 28 by the pivoting device 30 . in this way , in succession one filter element 28 can be cleaned at a time in the backflushing position , while maintaining ordinary filtration operation with the other three filter elements . for a different number of filter elements 2 , 3 , or 5 and more , then different staggering for the rotary motion by the free - wheeling sleeve is necessary . based on the kidney - shaped or arcuate configuration of the recess 44 on the bottom end 40 , it is moreover ensured for the re - positioning motion that filtration can largely continue always with three filter elements . the backflushing process for the respective filter element 28 can take place in a more or less continuous time intervals . it is also possible to ascertain via difference pressure measurements on the filter elements 28 when they are to be used for backflushing . the pertinent element could then be delivered directly to the backflushing opening 48 with the corresponding control . from the sectional representation shown in fig1 , the upper housing part 12 has a free cavity 60 with an axial extension corresponding more or less to the overall length of the filter elements 28 . this configuration has proven especially favorable in terms of energy and the resistance opposing the flow through the filter elements 28 in conventional filtration operation . the resistance of parts of the housing 10 is thus distinctly reduced . within the cavity 60 , essentially laminar flow behavior occurs . this helps flow reduce the outflow resistance in conventional filtration operation . the tubular wedge - wire screen filter elements preferably used have support rods tilted in the direction of the longitudinal axis 24 of the device and around which a wire section is wound into individual turns , with gaps through which fluid can pass being left open . in the area of each contact point of the wire profile with the support rod , a weld spot is located . the gap size provided for the free fluid passage , that is , the distance between two gaps , prevents passage of dirt if the particle size exceeds the gap width . dirt trapped in the gaps can then be removed from the filter device by the backflushing operation . the filter element 28 cleaned out in this way then moves from the backflushing position back into the filtration positions and can be used there for further filtration use . while one embodiment has been chosen to illustrate the invention , it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims .