Fischer-Robertson, Inc.
Nowata Backwashing Filter Systems
Internal & External Backwashing Systems
Manual & Automatic Control


nowata_proguard_but.gif (4656 bytes)Backwashing Filters & Backwashing Filter Systems
ProGuard
is a dedicated line of tubular backwashable filters. This means that the entire direction of the company, from design of the product to the sales force, is focused on the efficient design, production and use of these filter products in the field. Nowata Filtration products are built around the concept of meeting their customer needs. Fast needs assessment and quotes, flexible designs and manufacturing, and an experienced field sales force -- they all add up to provide you with responsiveness and the exact filtration system you need. DYNAMIC BALANCE: Automated ProGuard tubular backwash filters are designed to provide continuous, maintenance-free operation. The system continually monitors the dirt load coming into the filter and automatically decides to enter into the backwash cycle to clean the filter media. BETTER FILTERS, BETTER FILTRATION: The concept behind these filters is to allow continuous operation of your system, with filter cleaning taking place as needed. Permanent filter media reduce your ongoing costs and eliminate the need to dispose of contaminated filter media.


Backwashing Filter SequenceHOW PROGUARD BACKWASH FILTERS WORK: During normal operation, dirty, unfiltered fluid enters the ProGuard filter system through the filter media in an outside to inside flow path. Clean fluid then exits the filter and returns to the process through the outlet header.
PLC AUTOMATION: ProGuard pioneered the use of Programmable Logic Controllers (PLC) in tubular backwash filters. These highly dependable, programmable controllers activate the valve operation for the backwash cycle. A NEMA cabinet enclosure houses the PLC unit, and can be specified in a rain-tight or even explosion-proof configuration.
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Backwashable Tubular Filters1000 Series Manual Tubular Filters

General Information
ProGuard tubular filters provide a reusable permanent filter element, which eliminates the need to replace dirty, expended filters, as well as eliminating the need to dispose of dirty cartridges or bags. These filters are used in a variety of pulp & paper and other industrial applications.

Duplexed Manual Filters
When your process flow requires continual operation, it is a problem to change or clean a dirty filter element. A good option to straight by-pass is duplexing two single tubes into one filtration system. The creation of a duplexed system allows one tube to be on-line and one tube off-line in a standby mode. Then when the on-line filter becomes dirty, the operator can simply valve the tube off-line and switch the flow to the clean, standby vessel, thus eliminating interruption of the process, or complete by-pass of critical filtering.

Tubular Backwashing Filter System2000 Series Manual & Automatic Backwashing Filters

General Information
The Series 2000 Tubular Backwash Filters can be used in an extremely wide range of applications. They are particularly useful in processes where solids concentrations are relatively low and continuous operation is required. The expense of buying, storing and disposing of cartridges is eliminated by the Series 2000 permanent media available in wire mesh, fabric or wedge wire.

Standard Construction
The Series 2000 Filtration Systems feature 316 SS construction as standard. Carbon steel and carbon steel with epoxy lining are also available. Each tube is an all welded cylindrical housing containing a permanent filter element with 2" inlet, outlet and drain connections. The cap is a flat top, bolted type closure with a Buna O-ring seal. The stainless steel inlet and outlet headers are available in 4, 6, 8 and 10 inch sizes to handle specific flow rate requirements. Automatic backwash control is optional on the Series 2000 Systems. The standard systems are designed for a pressure range of 50 to 350 psi at a maximum of 250 F. Higher pressures and temperatures are available.

Automatic Backwash
The ProGuard Series 2000 Filtration System features a micro processor controlled backwash cycle. The state of the art programmable controller allows for backwashing at a predetermined time or differential pressure. Since there are no relays or contacts, the controls are virtually maintenance free. The controller can be changed in the field thereby tailored to fit in a specific application or process. The automatic backwash system can be optionally equipped with a manual override to facilitate troubleshooting and maintenance.

Filter Media
All ProGuard filter elements are 3 1/4" OD x 40" lg. for a total surface area of 410 square inches.

Backwashing Filter Media

  • Wire Mesh is available in ranges from 20 mesh (1/32") to 30 micron and consists of 316 SS woven wire cloth supported with a 316 SS perforated tube. The wire cloth exhibits excellent solids release characteristics and withstands high differential pressures. Specially woven wire cloth is available for filtration below 30 microns in specific applications.

  • Fabric Media is available in a variety of natural and synthetic fabrics to assure compatibility with a wide range of fluids and retain particles in the 1 to 250 micron range. Standard fabrics include polypropylene, polyester, nylon and cotton. The fabric is supported by a 316 SS screen and perforated tube. The fabric media exhibits higher flow rates per unit area than wire screens in the finer micron ranges. Fabric medias are especially suited for applications requiring 1 to 10 micron filtration. The perforated tube backup is designed to provide the structural strength required for filtering and backwashing.

  • Wedge Wire media is an all 316 SS triangular shaped wire wound around vertical supports and is available for retentions of 10 mesh (.063") to 15 microns. The wedge wire is excellent for highly viscous or abrasive slurries and will withstand very high differential pressures and temperatures.

Multi Pex Backwashing Filter System4000 Series Refinery Filters

General Information  
The catalysts used in many of today's processes for hydrocracking, hydrodesulfurizing and hydrotreating are designed for long service life, requiring more effective removal of solids from the feedstock to avoid premature and expensive replacement due to plugging. The cost of replacing a catalyst load is expensive, often as much as twenty to thirty times the price of an effective tubular filter system. 4000 Series tubular backwash filters, ASME Code designed and stamped, provide cost effective continuous protection for the life of catalytic reactors. The ProGuard Filtration System is designed for high temperature, high pressure critical refinery applications where low maintenance, continuous operations are a necessity.

Standard Construction
The 4000 Series filtration system is a self-contained, fully-assembled filter consisting of individual filter tubes with elements manifolded in parallel to common inlet, outlet and drain headers for either internal or external backwash. Pressurized fluid, from the outlet header or introduced through a connected backwash supply header, flows in reverse through the individual filter elements, carrying the collected contaminants to the drain. These filters are designed for up to ANSI Class 900 pressures and temperatures and feature carbon steel construction as standard. The inlet and outlet headers come in 4, 6, 8 and 10 inch pipe sizes to handle specific flow rate requirements.

Automatic Backwash
The ProGuard Series 4000 Filtration System features a maintenance free, programmable logic controller (PLC). The PLC allows backwash at a predetermined time or differential pressure. The PLC can also be interfaced from one filter bank to the next in large systems so that only one start signal is required to clean the whole system. The flexibility of a PLC allows for additional process monitoring functions not available with conventional electrical or pneumatic control systems. The backwash cycle is always accomplished with the system on-line, allowing continuous operating during cleaning and maintenance.

Filter Element
The 4000 Series filter element is a 316L Stainless Steel profile wire screen. The wire screen is suspended inside the filter body and is available in a variety of multi-cluster configurations, ranging from 3.5 ft square to 22 ft square of surface area per filter element. These multi-cluster configurations vary by the diameter of filter vessels as well as the diameter and length of the individual filter stalks that make up the multi-cluster element.

Multi Tube Backwash Filter System6000 Series Backwashing Filtration System

General Information
Tubular backwash filters are designed to remove solids from liquids by capturing the solids on a permanent reusable screen or filter element. At a predetermined pressure differential, the system reverses flow through each element in the filter, one element at a time, while the others continue filtering to provide a continuous operation. The ProGuard Filtration System is designed for high temperature, high pressure critical refinery applications where low maintenance, continuous operations are a necessity.

Standard Construction
The Series 6000 filtration system is a self-contained, fully-assembled filter consisting of individual filter tubes with elements manifolded in pairs to common 2" inlet and outlet connections. These filters are designed for ANSI Class 300 pressures and temperatures and feature carbon steel construction as standard. The carbon steel inlet and outlet headers come in 4, 6, 8 and 10 inch pipe sizes to handle specific flow rate requirements.

Automatic Backwash
The ProGuard Series 6000 Filtration System features a maintenance free, programmable logic controller (PLC). The PLC allows backwash at a predetermined time or differential pressure. The PLC can also be interfaced from one filter bank to the next in large systems so that only one start signal is required to clean the whole system. The flexibility of a PLC allows for additional process monitoring functions not available with conventional electrical or pneumatic control systems. The backwash cycle is always accomplished with the system on-line, allowing continuous operating during cleaning and maintenance.

Operation
Normal operation is for feed to flow from inlet to outlet to the reactor. There are, however, three ways to backwash the filters, depending on process requirements and the planned disposal of the backwash effluent. In all three systems the backwash effluent can be mixed with a lower grade product or reintroduced downstream of the reactor.

  • Internal Backwash - Internal backwash uses filtered feed available in the outlet header to clean the filter elements, washing the contaminants off the element's surface. Upon initiating the backwash sequence, the inlet valve closes, the drain valve opens and pressurized fluid in the outlet header is diverted backwards through the filter element, carrying the contaminants to the low pressure drain.
  • External Backwash - When small amounts of raw feed can be tolerated in the backwash effluent, an external, lighter product which has a solvent effect, such as diesel, can be used to clean the filter elements. External backwash also offers more control over flow rate and pressure than the internal backwash. Upon initiation of the cycle, both inlet and outlet valves close, and the backwash supply and drain valves open, reversing the flow through the filter elements.
  • Purge Backwash - In those instances where no raw feed can be left in the backwash effluent, a separate purge header is added using treated fluid to purge the raw feed towards the reactor prior to backwashing. After purging, the backwash cycle is completed in the same manner as an external backwash system.

Filter Element
The Series 6000 filter element is the 316 Profile wire or wedge wire screen. Recent advances in wire and filter element technology allows the use of 50% thinner wire, doubling the amount of open area on each element and increasing the throughput by 50%. The result is a durable, maintenance-free filter system with longer run times between backwash cycles, less backwash effluent and more upgraded product.

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