Series-PIConfiguration

Supported Applications

The Dwyer Series PI Piston In-Line Variable Area Flowmeter is designed for monitoring and controlling fluid flow in industrial processes involving compatible liquids. These mechanical piston variable area flow meters are intended for fixed installation only, providing visual indication via inscribed scale displays with a pointer or optional numeric digital LCD readout.

Operating Conditions & Performance

The Series PI operates across pipe sizes from 1/4" to 1" (8 to 25 mm) and flow rates ranging from 0.25 to 30 GPM (5 to 100 LPM). The series supports liquids with viscosity up to 650 centistokes maximum. Performance specifications include an accuracy of ±2% or ±1% FS (model selectable), repeatability of 1% of reading, and a response time of 250 ms.

Temperature limits are rated for process temperatures of 200°F (93°C) standard, with an HT option available up to 400°F (205°C); transmitters in the HT configuration support up to 300°F (150°C). Ambient temperature is limited to 150°F (65°C), or 105°F (41°C) for CSA listed models. Pressure ratings are defined by housing material: Aluminum and brass bodies handle 500 psi (34.5 bar), while 316 SS bodies support 1500 psi (103.4 bar) with a 3:1 safety factor.

Configuration Options

The series offers extensive configuration options for housing materials, process connections, wetted parts, and output signals to meet specific installation requirements.

• Housing Materials: Aluminum (A), Brass (B), or 316 SS (Z).
• Wetted Parts: Flow body in aluminum, brass, or 316 SS; piston in 316L SS; seals available in Buna-N or Viton®.
• Process Connections: Female NPT, SAE, BSPT, BSPP, or ANSI RF flanges (model selectable).
• Enclosure Ratings: Oil and dust tight NEMA 12 (IP52), weatherproof NEMA 4 (IP66), or weatherproof/corrosion proof NEMA 4X (IP65). Specific ratings include IP64 for AX0 enclosures and IP66 for ZX0.
• Output Signals: Options include display only, mechanical switches (SPDT/DPDT in various wire configurations), 4-20 mA analog output, HART® protocol communication, or intrinsically safe transmitters with approved barriers. Hazardous location switch outputs are available for R-box enclosures.
• Special Options: High vibration switches (A1B/L1B/Z1B), hermetically sealed switches (A53/L53/Z53), gold contact switches, and high-temperature configurations. Wall or foot mounting brackets are available as special options.

Power requirements vary by output: standard models require no power; 4-20 mA analog or HART® protocol outputs require 10-30 VDC (0.25 A @ 24 VDC); intrinsically safe transmitters require 10-24 VDC (0.25 A @ 24 VDC).

Key Product Differences

The Series PI distinguishes between standard and high-temperature configurations, with the HT option extending process temperature capability to 400°F (205°C). Enclosure types vary by material and rating: A-box (polysulfone), L-box (aluminum), Z-box (316 SS), T-box (aluminum with transmitter standard), and R-box (aluminum with higher resolution).

Switch configurations are differentiated by wire count, vibration resistance, contact type, and sealing. For example, A1/L1/Z1 denotes one SPDT 3-wire switch, while A2B/L2B/Z2B indicates two high-vibration SPDT switches. Hazardous location ratings apply specifically to R-box enclosures with designated outputs (e.g., One DPDT hazardous location). The series supports flow direction in any orientation: left-to-right, right-to-left, up, or down.