Ratio Controllers

WILLIAMS FIRE & HAZARD CONTROL® (WILLIAMS) Ratio Controllers are modified venturi foam proportioners that accurately meter pressurized foam concentrate into the firefighting water stream. These foam proportioners operate in conjunction with balanced pressure systems, such as bladder tanks and pumped proportioning skids. 

In operation, firefighting water flows through the modified venturi, creating an area of lower pressure referred to as the metering pressure drop. The metering pressure drop is directly related to the velocity of the water flowing through the venturi. The (1%, 3%, or 6%) concentrate-to-water ratio is maintained over the entire flow range for each size of ratio controller. However, each ratio controller has a minimum flow rate/velocity requirement which must be maintained for proper ratio controller operation. Available in three styles and various sizes.

Features 

• Delivers foam concentrate into firefighting water stream 
• Manufactured from ASTM 85-5-5-5 bronze 
• Consists of a body, metering orifice, and inlet nozzle 
• Inlet nozzle and metering orifice secured by a stainless steel retaining ring 
• Inlet nozzle tapered and machined to a smooth finish to maximize water stream efficiency 
• Metering orifice sized to the exact type and percentage of foam concentrate used