The AutoFilt RF3

Automatic Back-Flushing Filter for Process Technology

Designed for continuous and maintenance-free filtration in all sectors of industry.

The AutoFilt RF3 automatic back-flushing filter is a self-cleaning system for extracting particles from low-viscosity fluids. Its rugged construction and automatic back-flushing capability make a major contribution to operational reliability and reduce operating and maintenance costs.

The slotted-tube filter elements with filtration rates of 50 to 3,000 µmensure highly effective separation of contaminating particles from the process medium.

Automatic cleaning starts as soon as the elements become contaminated. The filtrate flow is not interrupted during the back-flushing procedure.

A range of filters of different sizes allows flow rates of up to 10,000 m3 per hour.

Numerous combinations of materials and equipment as well as individually adjustable control parametersallow optimum adaptation of the filter to any application.

Cost-Effectiveness of the AutoFilt R3

Particle contamination in operating fluids accelerates the rate of wear of system components, pipelines and valves and often leads to their premature failure. In many cases, the use of automatic back-flushing filters leads to a significant increase in service life and maintenance intervals.

Costs for new purchases, maintenance and waste disposal can thus be minimized.

AutoFilt Type RF3 - Some Examples of Applications

Power Stations
Treatment of industrial water for cooling generators and filtration of sealing water to increase the service life of the turbine shaft sliding-ring seals in hydroelectric power stations.

District Heat Supply
Protecting heat exchangers from clogging and wear.

Chemical Industry
Improving product quality by filtering process media.

Steel Industry
Protection of nozzles and pumps during high-pressure descaling, water treatment for cooling blast furnaces and rolling mills.

Sewage Treatment Plants
During production of industrial water, filtration of a take-off of the clear run can be used to save valuable drinking or well water.

Environmental Technology
Back-flushing filters are used as pre-filters before waste-water treatment plants (UV treatment, reverse osmosis, membrane filtration ...).

Mining
By filtering underground, water of an even quality is assured. This results in more reliable operation of pumps and disc-cutting machines.

Paper Industry
For example: the protection of spray nozzles for the screens of paper-making machines. This results in fewer failures causes by clogging and wear.

Automotive Industry
Mechanical Engineering
Machine Tools
Cooling lubricant emulsions can be kept much longer in circulation. This eases the pressure on the environment and reduces waste-disposal and repurchasing costs. Filtering of cooling and service water protects cooling channels and pipelines from clogging.

Operation of the AutoFilt RF3

Filtration
The fluid to be filtered flows through the slotted-tube filter elements of the back-flushing filter, passing from the inside to the outside. Contamination particles then collect on the smooth inside of the filter elements. As the level of contamination increases, the differential pressure between the contaminated and clean sides of the filter increases. When the differential pressure reaches its pre-set value, back-flushing starts automatically.

Triggering Automatic Back-Flushing
Back-flushing is triggered automatically:
- when the triggering differential pressure is exceeded;
- by means of an adjustable timer;
- when the TEST key is pressed.
As soon as back-flushing has been triggered, the filter starts to regenerate the filter elements.

Back-Flushing of the Filter Elements
- Back Flushing Cycle
- The geared motor turns the flushing arm under the filter elements to be cleaned;
- The back-flushing valve is opened;
- The pressure drop between filtrate side and back-flushing line flushes a small part of the filtrate backwards into the filter elements to be cleaned. The contamination particles collected on the inside of the filter elements are loosened and flushed back into the back-flushing line via the flushing arm.
- As soon as the "back-flushing time per element" has elapsed, the back-flushing valve is closed

All the filter elements are thus flushed in succession.
A back-flushing cycle is terminated when all the filter elements have been cleaned.

Special Features of the HYDAC AutoFilt RF3

Isokinetic Filtering and Back-Flushing
The special shape and configuration of the filter elements
-conical or conical/cylindrical - allows even flow, resulting in low pressure drop and complete cleaning of the elements. The advantage: fewer back-flushing cycles and lower loss of back-flushing fluid.

Pulse-Aided Back-Flushing
In control modes EPT and PT the flushing arm remains under each filter element for only a few seconds. Rapid opening of the pneumatic back-flushing valve generates a pressure surge in the openings of the filter elements that provides an additional cleaning effect to the back-flushing process.

Low Back-Flushing Quantities Due to Cyclic Control
The back-flushing valve opens and closes during back-flushing of each filter element.

The filters are designed specifically to ensure good flow conditions and enable compact dimensions with high filtration performance and low pressure drop.

Element Opening Quotient EFQx
The element opening quotient (EFQx) determines even flow without reverse flow through the filter element during filtering and back-flushing. The EFQx value is the ratio of the open filtration surface of an element to the cross section of the opening of the element inlet.

Variable Filter Isometry
The inlet and outlet flanges as well as the back-flushing line can be configured in different positions.  This means that the filter can be easily integrated into any plant layout.

Freely Selectable Control Parameters
The triggering differential pressure and back-flushing time per element can be adapted to best suit the process conditions. Timer relayscan be used to trigger additional cleaning intervals independently of the differential pressure. The control procedure is displayed via LEDs. A second microswitch on the pressure gauge can be used for external filter monitoring.

A static sealbetween the contaminated and clean sides of the filter makes it impossible for particles to penetrate the filtrate.

Ready-to-Operate Unit
The filter control unit and differential pressure measuring line are already connected. Once the filter has been fitted to the pipework, only the auxiliary power supply needs to be connected.

Summary of Technical Data

The Advantages of the AutoFilt RF3 ...
And the Benefits to You