Automatic Backwash Strainer
Body shall be fabricated out of M.S plate IS 226. Thickness of sheet & sizes shall
be as per table below, chamfered pipe with flanges shall be provided at inlet / outlet connections of the
Automatic Back Wash strainer. Butterfly valves shall be provided at inlet / outlet connections as shown in
drawing and included in BOQ. The Automatic Back Wash strainer body shall have two separate chambers properly sealed
to avoid mixing of filtered and unfiltered water. A powerful magnet shall be provided in the body to arrest MS particles.
Outer Filter shall be made out of Stainless Steel wire mesh Gr. SS-304 having 100 mesh with wedge type Groove to have more surface area for better cleaning & shall be removed after flushing the system and before commissioning.
Inner Filter shall be made out of 01 mm thick non-magnetic stainless steel having 03 mm perforation (40 mesh) Gr. SS-304 properly reinforced to avoid Damage of the element.
Method of Operation
Body MS fabricated IS:2002 this model has
less weight and cost than CI suction guide and very easy to
install in system.
Automatic strainer shall have Back-wash system for cleaning the filter elements: A heavy duty Reduction Gear motor unit of stainless steel Body shall be provided at top of upper lid of Automatic Back Wash strainer. A suitable stainless steel shaft SS-304 shall be provided for rotating the backwash arrangements having Bristle Brush for cleaning in side circumference of element. Shaft shall be supported with waterproof stainless steel bearing at the bottom for better movements of rotating arrangements. All moving parts of Back-Wash arrangement shall be of stainless steel SS-304. A connection of fresh water shall be provided, A spray section with Stainless steel Nozzles shall also be provided for spraying of element. Two motorized valve shall provided on fresh water connection & Drain. They shall close / Open with main starter of Drive motor when Back Wash system is in operation, all internally wired from works.
An inspection glass window 150 dia glass shall be provided at shell for checking the condition of element timely with help of a water proof light provided in the shell.
Body of Automatic Back Wash strainer shall be sand Blasted out side & Inside surface up to Conn.-125 NB & Above 125 NB all surface of Automatic Back Wash strainer shall be Painted with Polyester Epoxy Paint (MRF) shade Post office Red.
All hardware e.g. Studs, Nuts & other shall of Stainless Steel SS-304.
Test Pressure – PN 16.
Modes of operation
There are basically two modes of operation-intermittent and continuous. By turning the selector switch, the mode of operation can be selected.
Automatic Intermitient Position
With the selector switch in the “Auto” Position, the drive motor will start and the backwash valve opens as determined by the adjustable cycle timer or by the differential pressure switch.
The differential pressure switch is normally factory set at 1-1.1/2 psig over the anticipated clean pressure drop. Should a high differential pressure occur during the timed off period, the differential pressure switch will override the cycle timer and start or continue to backwash until the differential pressure is satisfied.
After the differential pressure has been satisfied, the strainer will continue to backwash for an additional 60 seconds (time delay relay).
The fluid Engineering Automatic Self-Cleaning Strainer would start a backwash cycle based on the timed sequence selected on the adjustable cycle timer. The timed sequence should be determined by each installation and the conditions experienced. The adjustable cycle timer can be programmed from 15 minutes to a 10-hour cycle (off) and for 01 to 10 minutes duration (on). Adjustable can be mode as conditions warrant them.
The selector switch is adjustable to “Manual” thus permitting the continuous mode. In the continuous mode, the fluid Engineering Automatic Self-Cleaning Strainer will be backwashing continuously with the backwash valve open and the drive motor running. This mode of operation may be necessary if the installation experiences high solid loadings.
02 Nos. Motorized valve may be provided at inlet & outlet connection to close & shut down while Back wash system is in operation at extra cost.
Sizes of various Pot Strainer, filter element & thickness of MS Sheet shall be as per table given below
|MS Plate thickness
Each Automatic Backwash Pot strainer shall be provided with manufacturer Test Certificate.
Specification of Y Strainer for Air Handling Unit
‘Y’ Strainer shall be fabricated out of MS ‘C’ class pipe two sizes higher than that of Strainer pipe size. Flanges as per B.S. 10 shall be provided at inlet and outlet connections. The body shall be pressure tested at 16 BAR and shall be hot dip galvanized. Permanent magnet shall be provided in the body of the Strainer to arrest MS particles. Filter element shall be of non-magnetic 20 guage SS Sheet with 3mm perforation. Strainers shall be provided at in let of each Air Handling Unit.
Specification of Y Strainer for Pumps
For Pump line Dust free cum Strainers shall be installed & the dust free unit shall be made out of MS ‘C’ Class pipe Two size higher than that of strainers pipe size, flanges as per BS-10 standard shall be provided at inlet & outlet connections. The Body shall be pressure tested at 16 Bar and Hot dip galvanized. ‘Y’ strainer shall have five media filter elements having different sizes of mesh for changing over for better filtration of water in system before commissioning.
First, Start system with less mesh of filter, then change filter with higher size of mesh simultaneously.
Finally keep for running system filter having 03mm perforation 40 mesh in a square inch. Rest all filter in media may be kept safe to repeat same method while cleaning the system again after six months or earlier, by using different type of Filters.
Filter Media: - A cartridge having five different type of filters made out of stainless steel SS-304, with different mesh shall be provided to have a dust free water for system.
Magnetic: - A powerful magnet is provided to attract the Iron fills.