The Model FP 450-80 Level Control Valve is a hydraulically controlled, diaphragm actuated, control valve that shuts at pre-set high reservoir level and fully opens in response to an approximately one-meter (three-foot) level drop, as sensed by the 3-Way altitude pilot mounted on the main valve.
The Model FP 450-80 is a pilot controlled valve equipped with an adjustable, 3-way, altitude pilot. The pilot senses the static head of the reservoir level via a tube  connected to a “still point” at the bottom of the reservoir. Should static head rise to pilot setting, the pilot  applies pressure to the control chamber  via cock valve , powering the main valve to shut.
Should static head fall below pilot setting by approximately 1m (3 ft), the pilot vents the control chamber, causing the main valve to fully open.
The 3-way cock valve  enables manual closing of the main valve.
For 8” valves and larger, an accelerator  quickens valve response.
The Level Control Valve shall shut at pre-set high reservoir level and fully open in response to an approximately one-meter (three-foot) level drop, as sensed by the 3-way altitude pilot mounted on the main valve.
Main Valve: The main valve shall be an elastomeric type globe (or angle) valve with a rolling-diaphragm. The valve shall have an unobstructed flow path, with no stem guide or supporting ribs. The body and cover shall be ductile iron. All external bolts and nuts shall be of Stainless Steel 316. All valve components shall be accessible and serviceable without removing the valve from the pipeline.
Actuation: Valve actuation shall be accomplished by a fully peripherally supported, one-piece balanced rolling-diaphragm, vulcanized with a rugged radial seal disk. The diaphragm assembly shall be the only moving part.
Control System: The control system shall consist of a 3-way, altitude pilot valve with a covered, centered spring and 8” (200 mm) sensing diaphragm, (for 10” and larger valves, an accelerator shall be added), an isolating cock valve, a 3-way cock valve, and a filter. All fittings shall be of stainless steel. The assembled valve shall be hydraulically tested.
Quality Assurance: The valve manufacturer shall be certified according to the
ISO 9000 and 9001 Quality Assurance Standard.
The Model FP 450-80 senses the static head of the water level in the tank by means of a high sensitivity pilot. To do so accurately, the sensing tube end must be connected to a “still point” at the bottom of the tank. The drainage pipe provides this “still point”, a location not influenced by flow velocity as in filling and outflow pipes.
In these reservoirs, the water level should be kept as constant as possible.
The Level Control Valve with modulating altitude pilot Model FP 450-82 is well suited to fulfill this requirement. The altitude pilot is highly sensitive to changes and accurately maintains level within a few centimeters. To do so, the sensing tube end must be connected to a “still point” at the bottom of the reservoir.
Model FP 450-82
The Model FP 450-82 modifies the Model FP 450-80 “On-Off” feature into a modulating feature to maintain an “always full” reservoir. The needle valve  continuously allows flow from valve inlet into the control chamber . The pilot  senses static head via sensing tube .
Should the static head rise towards pilot setting, the pilot throttles, causing the main valve to throttle closed, reducing filling rate, eventually closing drip tight. The downstream cock valve  enables manual control closing.