Adjustment shall be by means of readily accessible dial knobs, one for changing stroke length and the other for changing stroke frequency (speed). Both knobs are to be located opposite the liquid handling end. Control of Series C7 metering pumps shall be selectable between internal and external pulsing by means of a 3-position center-off switch. Stroke length shall be adjustable by means of readily accessible dial knob. When in external pulsed mode, Series C7 units shall accept signals without the use of electrical timer or internal timer. Pressure capacity shall be adjustable to reduce noise, vibration and wear.
To eliminate need for pressure relief valve, LiquiframTM shall automatically stop pulsating when discharge pressure exceeds pump pressure rating by not more than 35%.
Chemical metering pump housing shall be of chemically resistant glass fiber reinforced thermoplastic with a glass fiber reinforced polypropylene EPU carrier. All exposed fasteners shall be stainless steel. Chemical metering pump valves shall be ball type, with ceramic balls. Valve seat and seal ring shall be by replacing the combination seat-seal ring or cartridge valve assembly. Pump head shall be of transparent acrylic material capable of resisting the pumped chemical. Fittings and connections at pump head shall be PVC.
A total of 16 ft (4.8 m) of polyethylene tubing shall be provided per pump complete with compression connections. A foot valve with integral one piece strainer shall be provided for the suction line, and an injection check/back pressure valve with 1/2" NPT male connection for the injection point. The injection check valve shall incorporate a dilating orifice which prohibits scale formation and accumulation of crystal line deposits.
The pump drive shall be totally enclosed with no exposed moving parts. Solid state electronic pulser shall be encapsulated and supplied with quick connect terminals at least 3/16" (4.75 mm) wide. Electronics shall be housed in chemical resistant enclosure at the rear of the pump for maximum protection against chemical spillage.
