Double Check Valve Backflow Preventer

Basic information of Double Check Valve Backflow Preventer
This valve is installed in various pipeline systems to strictly prevent the backflow of the medium, and to protect the following medium or equipment from pollution.  Dof960 series of cases
Features of 4 double check backflow preventer / 1 double check backflow preventer / 2 double check valve backflow preventer
1. The double check valve is designed as a whole, with small structure；
2. Body is streamlined with little resistance loss；
3. Combination of a double check valve and safety drain valve can completely prevent backflow pollution under any working condition；
4. All moving parts are made of non-rust and wear-resistant materials with long service life.

Principle of Double Check Valve Backflow Preventer
Backflow preventers for two check valve series, when one of the seal damage, the other also ACTS as a seal to prevent backflow. However, when the sealing of double backflow valve / febco double check valve is broken at the same time, the check function is lost. Backflow preventers on the common type of foundation in the middle of the drain, so even if two check valve sealing at the same time damage, it can also play a role in preventing backflow pollution. 
Installation and Commissioning of Double Check Valve Backflow Preventer
This valve must be installed horizontally, the environment of the installation site should be clean, there should be sufficient maintenance space, the main degree of safety drain or (air barrier) outlet is more than 300mm above the ground, and it should not be flooded by water or debris, and the installation area should be equipped with drainage facilities.  For specific use, please consult ZECO Valve Group.
Part Material Standard
Body Ductile Iron EN 1563/DIN 1693
Bonnet Ductile Iron EN 1563/DIN 1693
Seat CuZn39Pb1 / C37000 EN12167/ASTM B135
Stem Stainless Steel 431 EN10088-1/ASTM A959
Spring Stainless Steel 431 EN10088-1/ASTM A959
Seal EPDM / NBR ISO 4633
For the materials options not listed, consult factory.
ZECO manufactures valves in more than 50 different alloys.
Product scope, Standards & Materials of Double Check Valve Backflow Preventer
Size Range: 2"~12"
Pressure Rating: 10bar ~ 25bar
Face to Face Dimensions: AMSE B16.10, EN558-1
Flange End Dimension: AMSE B16.1/16.42, AS4087, EN1092-2
Coating: Fusion Bonded Epoxy Coating
Inspection and Test: ISO 5208 / EN 12226-2
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