Series-RSF

Supported Applications

The Dwyer Series RSF Rotatable Scale Flowmeters are variable area flowmeters designed for the direct measurement of air, water, and other commonly used gases or liquids. These instruments feature a tapered borosilicate glass flowtube with a metallic float and a rotatable dual-scale shield that allows operators to read directly in SCFM/SLPM for air or GPM/LPM for water without correlation charts.

Operating Conditions & Performance

The series supports two primary material configurations, each with distinct operating limits. Brass/Stainless Steel models operate up to 250°F (121°C) and a maximum pressure of 150 psig (10.34 bar) @ 200°F (93°C). PTFE wetted parts are rated for temperatures up to 150°F (65°C) with a maximum pressure of 100 psig (6.7 bar).

Performance specifications include an accuracy of ±7% FS and repeatability of ±0.25% FS, based on the series data sheet values which take precedence over manual listings citing different accuracies. The flowmeters offer a turn-down ratio of 10:1 with direct reading scales marked at 127 mm.

Measurement Ranges

• Air: 5 SCFM (140 LPM) to 30 SCFM (900 LPM)
• Water: 1.2 GPM (4 LPM) to 5 GPM (20 LPM)

Configuration Options

The Series RSF is configurable across mounting styles, wetted materials, and valve options to suit specific installation needs.

Mounting & Housing Options

• In-line: Designed for vertical installation in process lines with two 3/8" female NPT connections. Overall height is 11-1/8 [282.58] inches.
• Panel Mount: Features a panel cutout requiring two 7/8" diameter holes spaced 9.469" (240.5 mm) apart. Includes a thick polycarbonate front shield for protection and a safety blow-out back panel.

Wetted Materials & Construction

• Brass/SS Models: Flowtube is borosilicate glass; floats, float stops, and end fittings are Type 316 stainless steel or brass. O-rings are fluoroelastomer.
• PTFE Models: Floats, float stops, end fittings, and O-rings utilize PTFE for chemical compatibility in specific applications.

Valve & Calibration Options

• Needle Valve: A 6-turn needle valve is standard on models indicated with a "V" suffix (e.g., RSF011V).
• NIST Traceable Calibration: Available as an option via NISTCAL-FL1 for air flowmeters and NISTCAL-FL2 for water flowmeters.

Safety & Installation Notes

The series includes a reflective lens background with 1.5X magnification to reduce parallax error. Safety warnings indicate that lines must be purged of dust prior to installation, and valves should be opened gradually after connection inspection. A leak test is recommended for hazardous fluids.

Key Product Differences

The Series RSF model numbering distinguishes between material construction, mounting type, valve inclusion, and flow range:

• Material Code: Models beginning with "0" (e.g., RSF011) indicate brass wetted parts; models beginning with "1" (e.g., RSF111) indicate Type 316 stainless steel.
• Mounting & Valve Suffixes: The third digit indicates the flow range. A trailing "V" denotes a model equipped with a needle valve, while its absence indicates no valve.