Automatic Recycle Valve Technical Article

Pressure Reducing Valve

You are here: Home » News » Technical Article » Pressure Reducing Valve
Applications of DATIAN ARC valve

16 Sep 2014/  /  in Pressure Reducing Valve Technical Article

The Model 720 Pressure Reducing Valve is a hydraulically operated, diaphragm actuated Control Valve that reduces higher upstream pressure to lower constant downstream pressure regardless of fluctuating demand or varying upstream pressure.

The Mode is a pilot controlled valve equipped with an adjustable, 2-Way pressure reducing pilot.

The needle valve continuously allows flow from the valve inlet into the upper control chamber. The pilot senses downstream pressure. Should this pressure rise above pilot setting, the pilot throttles, enabling pressure in the upper control chamber to accumulate, causing the main valve to throttle closed, decreasing downstream pressure to pilot setting. Should downstream pressure fall below pilot setting, the pilot releases accumulated pressure, and the main valve modulates open. The integral orifice between the lower control chamber and valve outlet moderates valve reactions. The needle valve controls the closing speed. The downstream cock valve enables manual closing.

The Pressure Reducing Valve shall reduce higher upstream pressure to lower preset downstream pressure regardless of fluctuating demand or varying upstream 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, pressure reducing pilot valve, a needle valve, isolating cock valves, and a filter. 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.

Network design requires establishing various pressure zones due to topography, distances, demands, energy costs, reservoir availability, etc. The pump supplies water to the network and to the reservoir. System pressure is too high for the residential neighborhood, requiring a pressure reducing system.

By-Pass Pressure Reducing Valve saves on maintenance costs. The larger (more costly to maintain) valve operates during peak demand. The smaller by-pass valve cuts operating hours of the larger valve, achieving greater return on investment. For high differential pressure systems, see BERMAD publication 720-PD Proportional Pressure Reducing Valve. For high pressure systems, see BERMAD publication 820 Piston Actuated Pressure Reducing Valve.