Patent Application
20190076761
The present disclosure relates to fluid filtration and in particular, filter assemblies employed in filtering fluids in single-pass and multipass systems and fluids employed for use where contaminants in the fluid cannot be tolerated. Fluid filtering systems for such purposes typically operate by receiving fluid under pressure, as for example fluid provided by a pump, and are typically connected through suitable conduits to the pump outlet and receive the fluid into a pressure vessel containing suitable filter media operative for extracting contaminants and discharging the filtered fluid to an outlet of the pressure vessel. The pressure vessel is typically provided with a removable lid for facilitating service of the filtration system components. Filters having this arrangement are typically used in industrial processes where fluid products are produced which require removal of contaminants for quality purposes; as well as applications where fluid requiring filtration is recirculated through a system requiring pressurized fluid; and, thus contaminants in the fluid must be removed in order that the process system components will not be affected or damaged by contaminants and will have the desired service life without the need to periodically stop the process and drain and replace the fluid.
In aforesaid fluid filter systems that incorporate a permanent filtration media element, it has been the practice to provide a way or means of periodically removing the trapped contaminants on the upstream side of the filtering media in order to prevent plugging of the filter media and to prevent an increased pressure drop across the filtering media. One practice utilized to regenerate a clean state in permanent filter media is the use of a mechanical wiper that periodically sweeps collected solids from the upstream face of the filter element. In this practice, the flow of fluid through the filter is uninterrupted by this self-cleaning process. Removed solids are collected in a sump in the pressure vessel and periodically removed through the opening of a purge valve, typically discharging to an atmospheric tank or drain. In order to assure removal of the contaminants during backwashing, one or more wipers have been provided, movable and sliding tangentially along the upstream side of the filter media. Heretofore, the wiper has been connected to an operating linear actuator member such as a piston and piston rod which is selectively movable by a remotely operated actuator connected to a portion of the rod extending through a sealed outlet in the pressure vessel. Other mechanisms such as threaded drive screws may provide the same translating motion to the wiper.
In providing such a wiper for the filtering media, it has been necessary to provide one or more separate wiper blades on a piston connected to the piston rod and to provide spring biasing of the wiper blades against the upstream side of the filtering media. In prior systems, employing an annular filtering membrane as the filtering media, arcuately configured individual wiper blades have been attached to a central mounting plate in radially sliding engagement with the blades arranged in a circumferential array about the piston. In such an arrangement, separate biasing springs have been required to urge each of the arcuately configured wiper segment blades in a radially outward direction to maintain the wiping function against the annular filtering media.
Referring to
In service, when replacement of the wiper blades in the aforementioned system is required, it has been necessary to remove the piston and operating rod and disassemble the wipers individually from the mounting plate and reassemble them thereon including placement of the individual bias springs and mechanical fastening of the arcuately configured wiper blades over the retaining pins onto the central mounting plate. This arrangement has required supplying for replacement a plurality of individual parts and has required a significant amount of labor to disassemble and reassemble the wiper arrangement. Accordingly, it has been desired to provide a simpler and less costly arrangement for wiping the upstream face of an annular filtering media in the aforementioned type of fluid filtration systems.
The present disclosure addresses the above-described problem and provides a unique one-piece integrally formed wiper for wiping the interior or upstream surface of an annular filtering media element employed for filtering fluid in a pressurized fluid system. The wiper described in the present disclosure is adapted to be readily and easily attached or removed from an operating piston rod employed in the filtration unit for being moved along the upstream surface of the annular filtering media for removing trapped contaminants therefrom and flushing of the contaminants to a drain outlet provided in the pressure vessel containing the annular filtering media.
The wiper of the present disclosure is formed integrally with a central annular hub having a plurality of circumferentially spaced spoke-like curved or non-linear radial springs formed integrally with the hub and extending radially outwardly therefrom. Each of the spoke-like radial springs has integrally formed at the radially outer end thereof an arcuately configured wiper. The ends of each arcuate wiper are angled in a manner to provide a degree of overlap between consecutive wipers, allowing for 100% coverage of the diameter surface of the filter element to be cleaned. These arcuate wipers form an annular array of circumferentially closely spaced arcuate wipers. Thus, the hub, radial spoke-like springs, and arcuate wiper elements may be integrally formed as a one-piece member. In the present practice, the one-piece wiper, hub, and spring member may be molded of polymeric material such as, for example, polyoxymethylene, polyacetal, or polyformaldehyde material, or other suitable resilient polymeric materials.
The wiper of the present disclosure thus permits a replacement for the wipers in a fluid filtration system which requires handling of only a single member or element which is easily and readily removed and replaced from the operating piston rod in the filtration unit.
Referring to
The upper end of the pressure vessel 12 is open and has an annular flange 18 provided thereabout and secured thereon by suitable means as, for example, weldment. The flange 18 has a plurality of circumferentially spaced apertures 26 formed therein which each have received therethrough fasteners such as bolts 28 for securing thereon a removable lid or closure 30. A gasket or resilient seal ring not shown in
The pressure vessel 12 has an inlet fitting 32 provided adjacent the upper end thereof and an outlet fitting 34 provided adjacent the lower end thereof, each of which fittings 32, 34 communicate fluidically with the interior of the pressure vessel and is adapted for connection to a fluid pressure line for providing flow of filtered fluid from the inlet 32 to the outlet 34.
An annular filter media assembly indicated generally at 36 is received in the pressure vessel and includes an annular filter media element 38 which has secured thereto an annular flange 40 at its upper end, and an annular flange 42 attached thereto at its lower end. Flanges 40, 42 are adapted to closely inter-fit and seal against the inner periphery of the pressure vessel 12 for preventing flow therearound. In the present practice, the flanges 40, 42 may each have a resilient seal ring provided thereon for sealing thereabout between the flange and the inner periphery of the pressure vessel, which seal rings are not shown in
A wiper assembly indicated generally at 44 is disposed within the filter media 38 and includes a combination wiper piston element or member 46, which will hereinafter be described in greater detail and which is attached to an operating or piston rod 48 by having a reduced diameter portion 50 which is received through the center of the member 46 and is secured thereon by a suitable fastening means as, for example, a self-locking nut 52 threaded thereon. The operating rod extends upwardly through an aperture 54 provided centrally in the lid 30 and is connected to a selectively activated linear actuator 56, which may be remotely actuated if desired, for providing sliding movement in a vertical direction for effecting movement of the wiper indicated generally at 44. The extent of travel range of the linear actuator 56 is such as to allow the wiper assembly 44 to translate across the entire length of filter media 38. Examples of such linear actuators are shown in U.S. Pat. Nos. 7,093,721 and 9,415,339.
Referring to
In operation, upon selected actuation, which may be accomplished remotely, the linear actuator 56 is operative to effect vertical movement of the operating rod 48 between the position shown in solid outline in
The filter assembly of the present disclosure thus provides an annular fluid filter element having a wiper piston disposed therein for selective movement to remove contaminants retained upon the filter. The wiper piston is integrally molded, as a one piece member, having a hub, radially outwardly extending spring members, and an array of a plurality of circumferentially closely spaced arcuately configured wiper elements thereon which are biased into contact with the inner periphery of the annular filter element. The wiper piston of the present disclosure thus is a readily and easily removable and replaceable element for servicing the filtration assembly.
The exemplary embodiment has been described and illustrated with reference to the drawings. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
