Flow control valves are best suited for regulating the fluid pressure and providing a positive shutoff in hydronic heating systems, boilers, indirect water heaters and chemical processing systems. Raptor Supplies is an authorised distributor of Apollo, Bell & Gossett, American Weldquip, Little Giant, Plast-O-Matic, Watts & Texas Pneumatic Tools check valves featuring aluminium / cast iron / bronze / iron / brass / PVC construction for providing protection against harsh abrasive liquids and working environments. These units come with threaded connections for ensuring a leak-proof operation. Plast-O-Matic constant flow rate thermoplastic valves come equipped with an in-built diaphragm for automatically adjusting to changing pressures and an orifice plate for maintaining the outlet flow within +/-15% of the pre-set constant value, without requiring any additional pre-adjustments or calibrations. They also have a retaining O-ring for maintaining a tight seal under both high & low pressures and eliminate metal contact with media for ease-of-use with ultra-pure & highly corrosive liquids. Choose from a wide variety of these valves offered in sweat & FNPT connections on raptor Supplies.