Specification SCOPE 1.1 This specification covers the design, manufacture, and testing of 2 in. (50 mm) through 48 in. (1200 mm) Swing-Flex® Check Valves suitable for cold working pressures up to 250 psig (1725 kPa), in water, waste- water, abrasive, and slurry service. 1.2 The check valve shall be of the full flow body type, with a domed access cover and only one moving part, the flexible disc. STANDARDS AND APPROVALS 2.1 The valves shall be designed, manufactured and test- ed to American Water Works Association Standard ANSI/AWWA C508. 2.2 The valves used in potable water service shall be certified to NSF/ANSI 61 Drinking Water System Components – Health Effects, and certified to be Lead-Free in accordance with NSF/ANSI 372. 2.3 Manufacturer shall have a quality management sys- tem that is certified to ISO 9001 by an accredited, certifying body. CONNECTIONS 3.1 The Valves shall be provided with flanges in accor- dance with ANSI B16.1, Class 125. DESIGN 4.1 The valve body shall be full flow area equal to nomi- nal pipe diameter at all points through the valve. The 4 in. (100mm) valve shall be capable of passing a 3 in. (75mm) solid. The seating surface shall be on a 45 degree angle to minimize disc travel. A threaded port with pipe plug shall be provided on the bottom of the valve to allow for field installation of a backflow actuator or oil cushion device without special tools or removing the valve from the line. 4.2 The top access port shall be full size, allowing remov- al of the disc without removing the valve from the line. The access cover shall be domed in shape to provide flushing action over the disc for operating in lines containing high solids content. A threaded port with pipe plug shall be provided in the access cover to allow for field installation of a mechanical, disc position indicator. 4.3 The disc shall be of one-piece construction, precision molded with an integral O-ring type sealing surface and reinforced with alloy steel. The flex portion of the disc contains nylon reinforcement and shall be warranted for twenty-five years. Non-Slam closing characteristics shall be provided through a short 35 degree disc stroke and a memory disc return action to provide a cracking pressure of 0.25 psig. 4.4 The valve disc shall be cycle tested 1,000,000 times in accordance with ANSI/AWWA C508 and show no signs of wear, cracking, or distortion to the valve disc or seat and shall remain drop tight at both high and low pressures. MATERIALS 5.1 The valve body and cover shall be constructed of ASTM A536 Grade 65-45-12 ductile iron or ASTM A126 class B gray iron for 30 in. (800mm) and larger. Optional body materials include ASTM A-351 Grade CF8M, stainless steel for sizes 3” (80 mm) through 12” (300 mm). 5.2 The disc shall be precision molded Buna-N (NBR), ASTM D2000-BG. Optional disc mate- rial includes Viton, EPDM, Hypalon. OPTIONS 6.1 A screw-type backflow actuator shall be provided (when specified) to allow opening of the valve during no-flow conditions. Buna-N seals shall be used to seal the stainless steel stem in a Lead-Free bronze bush- ing. The backflow device shall be of the rising-stem type to indicate position. A stainless steel T-handle shall be provided for ease of operation. 6.2 A mechanical indicator shall be provided (when spec- ified) to provide disc position indication on valves 3” (80 mm) and larger. The indicator shall have continuous contact with the disc under all operating conditions to assure accurate disc position indication. 6.3 A pre-wired limit switch will be provided (when spec- ified) to indicate open/closed position to a remote location. The mechanical type limit switch shall be activated by the mechanical indicator. The switch shall be rated for NEMA 4, 6, or 6P and shall have U.L. rated 5 amp, 125 or 250 VAC contacts. 6.4 An oil cushion device shall be provided when speci- fied to provide hydraulic control of the final 10% of valve closure and reduce valve slam and water ham- mer normally associated with rapid flow reversal con- ditions on pump shut down. The oil cushion device shall consist of a high pressure hydraulic cylinder, adjustable external flow control valve, oil reservoir, pressure gauge, stainless steel air inlet valve, and piping designed to control the closing speed of the last 10% of travel in 1-5 seconds. A threaded lead- free bronze dashpot bushing unit with a grease fit- ting for lubrication shall connect the cylinder to the valve and shall have an air gap to prevent hydraulic fluid from entering the valve and contaminating the water system. A snubber rod fitted with O-ring seals and rod wiper scrapers shall make contact with the lower portion of the disc’s stainless steel strike plate. 6.5 Available linings include rubber for abrasive or corro- sive fluids and glass for a smooth, non-stick surface. 6.6 A welded nickel seat is available for severe or abra- sive service. MANUFACTURE 7.1 Manufacturer shall demonstrate a minimum of five (5) years’ experience in the manufacture of resilient, flexible disc check valves with hydraulic cushions. 7.2 All valves shall be hydrostatically tested and seat tested to demonstrate zero leakage. When request- ed, the manufacturer shall provide test certificates, dimensional drawings, parts list drawings, and oper- ation and maintenance manuals. 7.3 The exterior and interior of the valve shall be coated with an NSF/ANSI 61 approved fusion bonded epoxy coating. 7.4 Swing-Flex® ufactured by Val-Matic® Check Valves shall be Series #500 as man- Valve & Mfg. Corporation, Elmhurst, IL. USA or approved equal. 7
