The Model 770-U Flow Control Valve is a hydraulically operated, diaphragm actuated control valve that maintains pre-set maximum flow, regardless of fluctuating demand or varying system pressure
The Model 770-U is a pilot controlled valve equipped with an adjustable, 2-Way flow pilot and an orifice assembly. The needle valve [1] continuously allows flow from valve inlet into the upper control chamber [2]. The pilot [3] senses the differential pressure across the orifice plate [4]. Should this differential pressure rise above pilot setting, the pilot throttles, enabling pressure to accumulate in the upper control chamber, causing the main valve to throttle closed, and limiting flow to the pilot setting. Should orifice differential pressure fall below pilot setting, the pilot releases accumulated pressure causing the main valve to modulate open.
The needle valve controls the closing speed. The downstream cock valve [5] enables manual closing.
The Flow Control Valve shall maintain pre-set maximum flow, regardless of fluctuating demand or varying system pressure.
Main Valve: The main valve shall be a center guided, diaphragm actuated globe valve of either oblique (Y) or angle pattern design. The body shall have a replaceable, raised, stainless steel seat ring. The valve shall have an unobstructed flow path, with no stem guides, bearings, or supporting ribs. The body and cover shall be ductile iron. All external bolts, nuts, and studs shall be Duplex® coated. All valve components shall be accessible and serviceable without removing the valve from the pipeline.
Actuator: The actuator assembly shall be double chambered with an inherent separating partition between the lower surface of the diaphragm and the main valve. The entire actuator assembly (seal disk to top cover) shall be removable from the valve as an integral unit. The stainless steel valve shaft shall be center guided by a bearing in the separating partition. The replaceable radial seal disk shall include a resilient seal and shall be capable of accepting a V-Port Throttling Plug by bolting
Control System: The control system shall consist of a 2-Way adjustable, direct acting flow pilot valve, an orifice plate, a needle valve, isolating cock valves, and a filter. The orifice shall be attached to main valve inlet. All fittings shall be forged brass or stainless steel. The assembled valve shall be hydraulically tested and factory adjusted to customer requirements.
Quality Assurance: The valve manufacturer shall be certified according to the ISO 9001 Quality Assurance Standard. The main valve shall be certified as a complete drinking water valve according to NSF, WRAS, and other recognized standards.
System design starts from expected flow range that determines major system components:
Significant deviation from designed flow range might disrupt water supply or even damage system components. Appropriate design, placement, and use of the Model 770-U protects the system from excessive flow. When pressure reducing is also required, choosing the Model 772-U, instead of the Model 770-U, completes the solution.
Protection against excessive demand that causes pump overload and cavitation damage, is achieved by sustaining pump flow within design specifications.
Since pump specifications vary, so do the required solutions:
Valve Patterns: “Y” (globe) & angle
Size Range: 11/2–32” (40-800 mm)
Flanged: ISO PN16, PN25 (ANSI Class 150, 300)
Threaded: BSP or NPT
Others: Available on request
Working Temperature: Water up to 80°C (180°F)
Body & Actuator: Ductile Iron
Internals: Stainless Steel, Bronze & coated Steel
Diaphragm: NBR Nylon fabric-reinforced
Seals: NBR
Coating: Fusion Bonded Epoxy, RAL 5005 (Blue) NSF & WRAS approved or Electrostatic Polyester Powder, RAL 6017 (Green)
Accessories: Bronze, Brass, Stainless Steel & NBR
Tubing: Copper or Stainless Steel
Fittings: Forged Brass or Stainless Steel
Body: Brass, Bronze or Stainless Steel
Elastomers: NBR
Springs: Galvanized Steel or Stainless Steel
Internals: Stainless Steel
Body: Fusion bonded epoxy Steel or Stainless Steel
Orifice Plate: Stainless Steel
Sensing Ports: 1/8” NPT
Please specify the requested valve in the following sequence: (for more options please contact us)