Series-HF

Supported Applications

The Dwyer Series HF In-Line Flow Monitors are designed for the direct measurement of flow in compatible gases, oil-based fluids, and water-based liquids (non-steam). These rugged monitors utilize a floating orifice disk combined with variable area technology to measure air, other non-corrosive gases, caustic fluids, high-pressure fluids, and high-temperature applications up to 400°F for specific models. The series is suitable for systems where flow occurs in one direction only; operation in the reverse direction can damage the monitor or system components.

Operating Conditions & Performance

The Series HF delivers an accuracy of ±2% FS over the entire range with a repeatability of ±1% of full scale. Process temperature limits vary by model: standard units operate up to 240°F (116°C), while specific high-temperature models support water-based fluids up to 400°F (204°C). Maximum viscosity is rated at 500 SSU.

Pressure ratings are differentiated by body material and media type:

• HFA, HFB, HFL, and HFH models: Rated to 600 psig (41 bar) for air/gas and 3500 psig (241 bar) for liquids.
• HFS model: Rated to 1000 psig (70 bar) for air/gas and 6000 psig (413 bar) for liquids.

To maintain accuracy, the manufacturer recommends system filtration of at least a 74 micron filter or a 200 mesh screen. The monitors are designed to operate without flow straightening or special piping but require installation in locations allowing easy access for reading and maintenance.

Configuration Options

The series offers configurable options across housing materials, process connections, and measurement ranges tailored to specific media:

• Housing Materials: Aluminum (HFA), Brass (HFB/HFH), 304 Stainless Steel (HFS).
• Process Connections: Available in female NPT sizes ranging from 1/8" to 2", including 1/4", 1/2", 3/4", 1", and 1-1/2".
• Wetted Materials by Model:
  • HFA: Aluminum casing, Buna-N seals, PTFE coated Alnico magnet, SS disk.
  • HFB/HFH: Brass casing, Buna-N seals, PTFE coated Alnico magnet, SS disk.
  • HFS: 304 Stainless Steel (or 303 SS per data sheet) casing, FKM seals with PTFE backup, PTFE coated Alnico magnet, SS disk.
• Measurement Ranges: Configurable for Air/SCFM, Oil/GPM (LPM), and Water/GPM (LPM). Specific ranges include 2-12 SCFM to 30-470 SCFM for gases; 0.5-5 GPM to 20-150 GPM for liquids.
• Display: A magnet follower located outside the body casing is magnetically coupled to an internal transfer magnet, indicating flow rate on a direct reading scale visible through a polycarbonate window tube.

Key Product Differences

The Series HF distinguishes models by housing material and intended service conditions:

• HFA (Aluminum): Designed for air or other non-corrosive gases. Not recommended for water applications.
• HFB (Brass): Intended for water-based fluids (non-steam).
• HFL (Aluminum): Configured specifically for oil-based fluids.
• HFS (304 Stainless Steel): Engineered for high-pressure fluid applications, offering the highest pressure ratings in the series.
• HFH (Brass High Temperature): A brass body variant rated for water-based fluids up to 400°F (204°C).

Note: Aluminum and brass monitors should not be used where piping is unsupported, as heavy weight can cause the monitor to bend. When installing aluminum or brass units onto steel pipe, care must be taken not to over-tighten threads.