North American Adjustable Port Valves Adjustable Port Valves for HOT or COLD AIR, GAS, OIL, WATER, STEAM 3" Adjustable Port Gas Valve Beck Electric Operator 2½" Adjustable Port Air Valve Honeywell Pneumatic Operator 6" Adjustable Port Air Valve Honeywell Electric Operator 4" Adjustable Port Gas Valve Honeywell Electric Operator 10" Adjustable Port Air Valve Pneumatic Operator 1¼" Adjustable Port Gas Valve Barber-Colman Electric Operator LOW TORQUE — ROTARY PLUG — EASILY CLEANED pressure drop adjustable for best flow characteris

CORRECT VALVE SIZING Fixed port valve Made Easy Flow rate, % of rated capacity Curtain ½ open Core full open Curtain ¾ open Core rotated ¼ Quick opening Adjustable Port valves can be characterized to a variety of curves to match system requirements. Curtain ¾ open Core rotated ½ 0 Figure A. Turning curtain adjusting knob changes port opening so valve can constitute optimum resistance in the system for good control. For a valve operated by a modulating type control, either a linear or an equal percentage characteristic is preferred for most applications. These characteristics are shown in Figure...