Quick Pressure Relief Valve
■ Immediately eliminates pressure peaks ■ Visual indication of system over pressure ■ Filtration system burst protection ■ Thermal expansion over-pressure relief ■ System maintenance savings
The Model 73Q Quick Pressure Relief Valve is a hydraulically operated, diaphragm actuated control valve that relieves excessivesystem pressure when this pressure rises above the pre-set value. It immediately, accurately, and with high repeatability responds to system pressure rise by fully opening. The Model 73Q provides smooth drip tight closing.
Features and Benefits
Independent operation Long term drip-tight sealing term setting stability Wide setting range Tight setting windowhysteresis valve closing (no surges)
❏ Long ❏ ❏
❏ Minimal ■
Double chamber design
❏ Moderated ❏
■ ■ ■
Obstacle free, full bore – Uncompromising reliability Balanced seal disk – High relief flow capacity Manual test valve – No setting change required
The Model 73Q is a pilot controlled valve equipped with anadjustable 2-Way pressure relief pilot. The pilot internal restriction continuously allows flow from the main valve inlet into the upper control chamber . The pilot  senses upstream pressure. Should this pressure abruptly rise above pilot setting, the pilot opens, and pressure in the upper control chamber is vented, causing the main valve to immediately open, thereby relieving excessivesystem pressure. When upstream pressure decreases to below pilot setting, the pilot closes, enabling pressure to accumulate in the upper control chamber, causing the main valve to smoothly close. Vented cock valve  is used to perform manual operating test. For sizes 6-14” use pilot #3HC. For sizes 16" and larger, consult BERMAD.
Valve Closed (systempressure is below setting)
The Quick Pressure Relief Valve shall relieve excessive system pressure when this pressure rises above pre-set value. It shall immediately, accurately, and with high repeatability respond to system pressure rise by fully opening as well as provide smooth drip-tight closing. 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 serviceablewithout 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 separatingpartition. 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, quick pressure relief pilot valve, a testing cock valve, and a filter. All fittings shall be forged brass or stainless steel. The assembled valve shall be hydraulicallytested 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.
Reduced Pressure Zone Safety...