Frequently Asked Questions
Engineers and operators throughout the municipal, industrial and irrigation markets use a variety of terms to specify or describe Forsta’s self-cleaning filters. The language in a spec may be as simple as “water filter.” The following detailed terms have also been used in official spec language:
Automatic Self-Cleaning Filter, Automatic Water Filter, Self-Cleaning Strainer, Service Water Strainer, Automatic Suction Scanner, Screen Filter, Self-Cleaning Screen Filter, Inline Screen Filter, Automatic Sediment Removal Filter, Motor-Operated Strainer, Backwashable Screen Filters, Horizontal Self-Cleaning Filters, Vertical Self-Cleaning Filters and more.
Submit a spec for review to firstname.lastname@example.org if you have questions about whether or not Forsta’s equipment meets project requirements.
A. Refer to the numbered diagram above and corresponding answers below to understand the 3 checkpoints for success.
1) Confirm screen selection is appropriate for source water quality.
Click here or scroll down to learn more about screen selection based on water source.
2) Check for sufficient inlet pressure during backwash.
All Forsta self-cleaning water filters utilize system pressure to drive the internal cleaning mechanism. A minimum of 35psi (15psi for Low Pressure models) is required for proper backwash performance. This should take into account the flow and head loss expelled through the flush valve as well as the system flow.
3) Minimize back pressure on the flush line.
Since backwash is based on system pressure, it is critical that the flush piping be designed in such a way as to minimize back-pressure. Ideally the flush piping will be over-sized and installed to discharge to a nearby tank or drain. Minimizing pressure in the flush line will help optimize self-cleaning performance.
2-30 seconds depending on the filter model and operating pressure.
See graphic below.
Water sources may be used for a wide range of applications throughout industrial, irrigation and municipal sectors. Knowing the water source, particle type and end use of water is a great way to assess filtration needs.
Filtration by water source: reservoir water filtration, river water filtration, canal water filtration, lake water filtration, pond water filtration, tank water filtration, ditch water filtration, well water filtration, process water filtration, cooling water filtration, effluent water filtration, reuse water filtration, wash water filtration, service water filtration, seawater filtration, ballast water filtration, surface water filtration, produced water filtration, brackish water filtration, potable water filtration, utility water filtration, wastewater filtration, reclaimed water filtration, non-potable water filtration, groundwater filtration, municipal effluent filtration.
Screen sizes are available from 5 to 4,000 micron.
Changing the screen on your Forsta Self-Cleaning Filter is quick, easy and requires no special tools. See below to watch the ~1 minute screen change on an ML3-90 series filter.
A particle size analysis (PSA) and total suspended solids (TSS) value (in ppm or mg/l) are required to address this question. Particle size, concentration and total volume will dictate the solids reduction that can be achieved with any given screen size. View the chart below to review a sample particle size analysis.
Yes. The “filter cake effect” describes the fact that degree of filtration becomes finer as a screen accumulates dirt (differential pressure increases.)
In the case study shown below, data will demonstrate results of the filter cake effect in an industrial cooling tower system.
There is no minimum flow requirement for normal operation, but the minimum requirements for backwash are 40gpm.
A minimum of 35 psi is required at the inlet of the filter during the backwash. Low Pressure Series self-cleaning filters require 15 psi at the inlet of the filter during the backwash.
Backwash frequency will depend on the water quality and degree of filtration.
The filter can be inspected once every six months to a year.
Standard materials include epoxy-coated carbon steel and stainless steel 304L and 316L. High grade alloys including duplex, super duplex, and Titanium are available upon request. Fiberglass reinforced plastic is also used for high chloride environments such as seawater, produced water, and brine.
Yes. Forsta self-cleaning filters are customizable in material, orientation, flange spacing, screen type, motor, controller type and more. Advise Forsta engineers about the needs of your project and they will work with you to create a custom filtration solution.
Yes, Forsta has been approved as an equivalent for specifications naming a wide variety of vendors of automatic self-cleaning filters, automatic self-cleaning strainers, automatic brush filters, automatic suction scanners, auto backwashable filters, auto backwash strainers, etc.
Stock items may be assembled and shipped same day. Non-stock items usually ship in 4-6 wks.
Yes, contact Forsta Filters to find the installation nearest you.
Yes, small units may be piloted for a fraction of the cost of purchasing a large unit. Generally, some portion of the rental fee may be applied to the purchase of a larger unit.
Call us today at 310-837-7177 or fill out our contact form and we’ll be in touch with you right away to make sure your filtration needs are met!Request a Quote