2000 Hook-up Book

Figure II-18 25 BP Back Pressure Controls used to Restrict Supply to Low Priority Uses at Times of Overload

Pilot Operated Pressure Reducing and Back Pressure Valve

Pilot Operated Back Pressure Valve

Safety Valve

Drip Pan Elbow

Strainer

Steam to Non-essential Service

Reduced Steam Pressure to Non-essential Service

Strainer

Steam Supply from Boiler

Steam to Priority Use

Header

Thermo-Dynamic Steam Trap with Integral Strainer

HOOK-UP DIAGRAMS

At times of peak draw off, boilers which have sufficient capacity to meet average load conditions may become overloaded. This can cause carryover and priming, or even lockout of boilers on low water. The pressure in the steam lines falls and essential services may be interrupted. The use of back pressure controls in the supplies to non-essen tial loads allows these to be automatically shut down, in order of priority, at peak load times while maintaining supply to more important loads.

Spira-tec Loss Detector

Figure II-19 Reducing Steam Pressure Using 25PA Control Valve with Remote Air Valve

10 Pipe Diameters Minimum from Valve Outlet

Safety Valve

Air Loaded Pilot

Pressure Sensing Line Pitch Down

Drip Pan Elbow

Moisture Separator

Steam Supply

Strainer

Reduced Steam Pressure

Air Operated Control Valve

Filter/Regulator

Air Supply

Spira-tec Loss Detector

Check Valve

Depending on pilot selected, reduced steam pressure will be approximately 1:1, 4:1 or 6:1 times the air loading pressure sent to the pilot.

Strainer

Float & Thermostatic Steam Trap

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