Ronningen-Petter Tubular Pressure Filters are all based
on a carefully engineered, in-line, tubular design that feeds pressurized unfiltered
liquid upward, along, and through the filter element. Elements are wire mesh, slotted or
perforated stainless steel or woven fabric made from polypropylene, polyester, or other
select materials. Filtered liquid discharges from the top of the unit. This flow pattern
assures that all contaminants are collected on the outside of the element for easy
cleaning.When multiple filters are connected to headers, the connection area on the
headers is first "pulled," creating a radial flow path. This eliminates the
sharp 90o angles that increase pressure drop. Individual filter housing inlet
and outlet nozzles are also gradually curved for the same reason.
Clean-In-Place Systems: To ease media inspection the filter tube can be disassembled in seconds without tools. Quick-acting couplers are positioned at inlet and outlet ports as well as on the body connection. Dual tube and multiple-tube clean-in-place systems provide truly continuous service because individual tubes can be valved off stream for cleaning while remaining tubes continue to filter. To achieve continuous flow with other designs, such as cartridge or bag units, usually requires a completely redundant filter system, as well as piping, valves, and controls. Single and duo-filter systems are very compact, plus they can be installed vertically, horizontally, or on an angle without any affect on their performance. Multiplex clean-in-place filter systems are also surprisingly compact to start with, plus any system with four or more tubes can be arranged in a back-to-back configuration for a 50% savings in length.
External Backwashing Systems:
In an external filter, liquid from another source is used as the backwashing medium. This type of unit is recommended for applications where the filtrate is too viscous to effectively clean, where the loss of the filtrate in backwashing is economically prohibitive, or where the backwash supply flow rate and/or pressure is lower than the recommended minimum for an internal backwashing filter. For external backwashing, a backwash supply header is added. This backwash header supplies the filter with clean liquid, at the required flow and pressure to clean the filter elements. The upper backwash supply / outlet header valves are interconnected with the inlet / drain header valves at the bottom so that both may be operated with a single lever per tube.
The backwash cycle is initiated by rotating this lever. This isolates the filter tube from the inlet and outlet headers while simultaneously opening the filter tube to the backwash supply and drain headers. Another valve on the backwash header is then opened to introduce a surge of external backwash liquid. Residual backwash liquid is evacuated from the filter body by closing the backwash supply valve while keeping the drain open.
Internal Backwashing Systems:
Internal backwashing multiplex systems have individual elements valved in parallel to common inlet, outlet, and drain headers. During backwashing a portion of the pressurized filtered liquid in the outlet header is used as the backwashing medium. This is called an internal backwashing system as the filtrate itself is used for backwashing. The backwash cycle is initiated by the rotation of a ball valve at the inlet of the tube to be cleaned. This simultaneously closes the tube to the inlet header and opens it to drain. A portion of the filtrate from the tube(s) remaining on stream then surges in reverse from the outlet header, through the screen, backwashing solids to the drain. This process is then repeated for each tube.
Internal systems are generally used on applications where the process liquid is sufficiently free-flowing, where the value of the liquid is low, and where the system can be designed with proper flow and pressure characteristics.
Automatic Multiplex Filter Systems: With automatic systems cleaning (backwashing), is controlled by changes in differential pressure across the filter media. As solids build up on the media, this differential pressure increases. When it reaches a preset level, the filter system automatically initiates cleaning. As a result, the system is always adjusting to process dynamics. Cleaning is never initiated too late, which could reduce throughput and eventually lead to plugged media and major process problems. Cleaning is never initiated to early which could waste valuable process fluid. Automation control is offered in printed circuit, digital, and pneumatic packages. Each is equipped with proven industrial grade componentry housed in NEMA 4 standard or special enclosures to suit industrial environments. Wiring on all automation packages is in accordance with U.S. National Electrical Code Requirements and has been CSA approved.
RPA Process Technologies
9151 Shaver Road
Portage, MI 49024
Toll Free (US only):
1-800-656-3344
Voice: +1 269 323-1313
Fax: +1 269 323-0065
www.RPAprocess.com
info@RPAprocess.com