The SFCT automatic backwashing filter system is used to filter low-viscosity, large flow and high-speed fluids. SFCT filters are widely used in metallurgy, chemical industry, power industry, re-injection of water in oil field, ballast water in shipping industry and water treatment. The filter system consists of a main housing, gear motor, inlet and outlet ports, filter screen elements, a drain valve, pneumatic actuator, pressure differential meter, and a control system.

Automatic Backwash Filters

Automatic Backwash Filters

1.   PROCESS

The process begins with fluid flowing through the inlet. The fluid enters the filtration screen through the inlet of the filter. Then, the fluid flows from the inside of the screen to the outside. As the fluid flows through the wedge-wire / multi-layered filter screen, solid impurities that are larger in size than the screen’s micron rating become trapped on the inside of the screen. The filtered fluid exits the system through the outlet. As the impurities accumulate on the inside of the screen, a pressure differential is created, and will continue to increase between the contaminated and clean sides.

2.   CONTROL PANEL MODES OF OPERATION

The process begins with fluid flowing through the inlet. The fluid enters the filtration screen through the inlet of the filter. Then, the fluid flows from the inside of the screen to the outside. As the fluid flows through the wedge-wire / multi-layered filter screen, solid impurities that are larger in size than the screen’s micron rating become trapped on the inside of the screen. The filtered fluid exits the system through the outlet. As the impurities accumulate on the inside of the screen, a pressure differential is created, and will continue to increase between the contaminated and clean sides.

  • The SFCT filter’s control system monitors the rising differential pressure.
  • The filter systems are equipped with a pressure differential meter through which the end-user sets the differential pressure requisite (i.e. pressure dependent setting) to automatically start the backwash cycle. When this differential pressure is reached, the control system sends a signal to start the backwash cycle.
  • The backwash cycle can be initiated at pre-defined time intervals.
  • Pressure dependent settings takes precedence over time dependent settings.
  • The primary usage is for commissioning and testing.
  • The backwash cycle can be started by pressing the ‘MANUAL’ button.
  • In manual mode, there are no pressure or time setting controls.

3.   BACKWASH CYCLE

  1. The backwash cycle cleans the filter element.
  2. The gear motor is connected to the middle shaft and drives the cleaning backwash arm to the element being cleaned.
  3. The drain valve is then opened by a pneumatic actuator which draws clean filtered fluid from the outside of the screen to the inside, whereby the impurities are flushed down into the drain line.
  4. When the duration of the backwash cycle is reached, the drain valve closes and the backwash cycle is completed. .

DESIGN ADVANTAGES AND FEATURES

  • Automatic online continuous filtration – the filter system does not have to be taken offline to enter the cleaning mode because the backwash cycle cleans the screen segment wise without interrupting the fluid flow and continue filtering the fluid.
  • A gear motor is used to drive the filter backwashing system.
  • The unique and innovative internal structure ensures delivery of a high-quality backwashing and filtration system.
  • Provides the end-user with long term operation and precision filtration with no flow interruption. Impurities are easily flushed away from the filter screen.
  • The filters are equipped with wedge wire screen or multi layered filter element. These elements provide precision filtration (as fine as 50μm), are corrosion resistant, and sustain much more wear and tear.
  • Cost effective, easy to operate, requires minimal maintenance and is environmentally friendly.
  • The control system can be tailored to monitor pressure and time settings for various fluids.
  • Compact design – installation requires minimal space and is easy to install. The inlet and outlet ports are adjustable according to the end-user’s requirements.

APPLICATIONS

  • Seawater desalination
  • Side Stream Filtration
  • Cooling Water Filtration
  • Spray Nozzle Water Filtration
  • Recycling of cold water
  • Water re-injection in oil fields
  • Ballast water in shipping industry
  • Recycling of flash steam from boiler
  • Pre-filtration for ultra-filtration and reverse osmosis
Multi Layered Filter Screen
Automatic Backwash filter being installed at site

Automatic Backwash filter being installed at site