The KOBOLD SV is a float-type variable area flow meter that combines direct visual flow indication with optional reed switch outputs in one compact, vertically mounted instrument. Operating up to 145 PSIG with ±5% full scale accuracy, the SV series measures clean liquid and gas flows in industrial applications. Manufactured in Pittsburgh, Pennsylvania, the SV is BABA compliant for federal project eligibility.
Flow Measurement and Switching in One Instrument
The SV series eliminates the need for separate flow meters and switches. Direct-reading scales calibrated in GPM (water) or SCFM (air) provide visual flow indication, while optional reed contacts enable automated process control or alarms. This integrated approach reduces installation costs, piping connections, and potential leak points.
Switch configurations include a normally open single contact or an SPDT changeover contact. The magnetic reed switches are physically separated from the process to prevent contamination and carry an IP65 electrical protection rating for use in industrial environments.
How the SV Float Design Works
The SV operates on the well-known float principle but replaces the open conical measuring tube with a cylindrical control tube that has a conical groove along its axis. The upper edge of the float indicates the flow rate against a scale printed on the borosilicate glass metering tube.
A built-in permanent magnet in the float actuates the reed switch mounted on the exterior housing, so the switch is hermetically separated from the medium. Optional switches are user adjustable, and this stabilized-float design offers a large measuring span in a small instrument.
Flow Ranges and Process Connections
The SV series offers thirteen calibrated flow ranges spanning 0.075 GPM to 40 GPM for water. Air models reach 150 SCFM, starting as low as 0.25 SCFM on brass units and 0.6 SCFM on stainless steel. Process connections are NPT threaded fittings from 1/4 inch through 1-1/4 inch in nickel-plated brass or 304 stainless steel.
The gold anodized aluminum housing with a borosilicate glass viewing window maintains clear float visibility, and the cylindrical design provides a smaller footprint than traditional conical glass rotameters. Vertical mounting with upward media flow allows installation in tight spaces.
Materials and Media Compatibility
Process-wetted components are available in nickel-plated brass for general water and air service or in 304 stainless steel for enhanced chemical resistance. Float materials include nickel-plated brass, 304 stainless steel, polypropylene (PP), and PVDF, with NBR seals on brass units and FKM seals on stainless steel units.
The instrument's maximum tolerances were determined using water and air, so chemical compatibility with the wetted materials should be confirmed before using other media. Media containing solids should be filtered upstream; KOBOLD offers a magnetic/screened filter (type MFR) suitable for this purpose.
Temperature, Pressure, and Certifications
According to specifications, the SV series operates at media temperatures up to 212°F (100°C) with brass or stainless steel floats and up to 158°F (70°C) with PP or PVDF floats. Maximum operating pressure is 145 PSIG, suitable for most cooling systems, water flow monitoring applications, and other common industrial uses.
The reed switch versions carry cCSAus approval, and the switch housing is rated IP65.
Made in USA and BABA Compliant
Manufactured in Pittsburgh, Pennsylvania, the SV series complies with Build America, Buy America Act (BABA) requirements. BABA compliant models are available for federally funded infrastructure projects, government contracts, municipal water and wastewater systems, and public transportation projects requiring American-made instrumentation.
Typical Applications
The SV series measures vertically upward flow of clean liquids and gases in cooling system monitoring, process water distribution, process air measurement, and plant utilities. The combination of visual indication and optional switching suits applications requiring both operator visibility and automated control.
- Water treatment and process water systems
- HVAC and industrial cooling circuits
- Compressed air and pneumatic systems
- Plant utility monitoring
Common Questions about SV - Float-Type Flow Meters and Switches
A float rides inside a cylindrical control tube machined with a V-groove, and its upper edge lines up against the printed scale to show the current flow rate. A permanent magnet inside the float trips the externally mounted reed contact at the setpoint, keeping the switch fully isolated from the process fluid.
Thirteen factory-calibrated ranges cover water service between 0.075 and 40 GPM. For air, brass models begin at 0.25 SCFM and stainless steel models at 0.6 SCFM, with the largest range reaching 150 SCFM. Scales read directly in GPM for water or SCFM for air.
The reed contacts switch a maximum of 240 VAC at 0.42 A and 100 W, or 230 VDC at 0.26 A and 60 W. At lower voltages, higher current is permitted: 1 A at 100 VAC or at 60 VDC. A normally open contact is standard, with SPDT changeover optional.
Yes. Loosening the hold-down screws lets the reed contact housing slide along its rail to the desired trip point on the scale, and the manual provides step-by-step procedures for setting either increasing-flow or decreasing-flow actuation. Once the contact actuates at the target flow, the screws are simply retightened.
Install the unit vertically with the flow inlet at the bottom so the medium travels upward through the meter. Keep the meter away from large ferritic masses and strong electric fields, which can hamper the reed contact, and consider a downstream flow control valve so pressure can be introduced gradually.
No. Flow indication is purely mechanical: gravity and magnetism do the work, with no springs, diaphragms, or other active mechanisms to power or wear out. Wiring is only needed when the optional reed contact is used for switching, alarm, or automated control circuits.
All models handle up to 145 PSIG. Temperature limits depend on the float material: metal floats are rated to 212°F (100°C), and PP and PVDF floats to 158°F (70°C), according to specifications. Fluid must never be allowed to freeze inside the sensor.
Yes. SV flowmeters are produced at KOBOLD's facility in Pittsburgh, Pennsylvania. Configurations meeting Build America, Buy America sourcing rules can be specified for government and municipal work, from water utilities to transit systems, where federal funding requires domestically manufactured instrumentation.
Product Specifications
Liquid Ranges
0.075...0.35 to 2.5...40 GPM
Gas Ranges
0.25...1.25 to 10...150 SCFM
Fittings
¼"...1¼" NPT Threads
Material
Ni-plated Brass, SS
Max. Temperature
158°F (70 °C) / 212 °F (100 °C)
Option
N/O or SPDT Reed Contact
Media Categories
Liquid or Gas
Product Features
Direct Reading Scales for Water and Air
Vertical Connections for Easy Installation
Certifications/Approvals: cCSAus
BABA (Build America, Buy America) compliant models available
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