The KOBOLD KSV is a compact variable area micro flow meter that measures low flow rates of water and air, offering a dependable and cost-effective solution for applications where space is tight and accuracy is essential. With its economical price and fast delivery, it is the go-to instrument for engineers who need reliable flow measurement without the premium of complex electronics.
Designed for panel installation, the KSV pairs a compact body with 1/8 inch NPT female fittings that drop neatly into instrument panels, control cabinets, and OEM equipment enclosures, delivering a clear, direct reading with no electronics required. An optional integrated needle valve provides simple flow control and is generally recommended, particularly for gas applications, to help stabilize the float during media introduction.
How the KSV Works: The Variable Area Measurement Principle
Flow enters from the bottom of a vertically oriented tapered tube. The float inside rises until the upward drag force from the flowing fluid exactly balances the downward gravitational force on the float. At that equilibrium point, the float's position indicates the flow rate, read from the graduated scale on the tube.
This mechanical principle requires no external power and produces an instantaneous, direct reading. Because each KSV is calibrated for water or air, readings stay accurate and repeatable with no need for density corrections or added signal processing. Learn more in our Article on Variable Area and Rotameter Flow Technology.
Flow Ranges, Pressure, and Temperature Ratings
The KSV measures water-based liquids from 0.04...0.4 GPH up to 2...20 GPH and air from 0.3...3 SCFH up to 10...100 SCFH. The flow meters are rated up to 87 PSI and for temperatures between -4°F and 248°F (-20°C and 120°C), according to specifications.
According to specifications, accuracy is ±6% of full scale with ±1% of full scale repeatability, keeping readings consistent run after run. The datasheet also states the KSV can be sterilized at up to 250°F (121°C).
Materials and Chemical Resistance
The polysulfone body, combined with either 303 stainless steel fittings and FKM seals or brass fittings and NBR seals, provides excellent chemical resistance for a variety of media, including acids and alkaline solutions. This suits the KSV to process fluids well beyond pure water.
O-ring seals keep the meter leak tight, and the float material varies with the chosen flow range: glass, stainless steel, or titanium.
Panel Mounting and the Optional Needle Valve
The KSV is designed for panel mounting and installs vertically, with flow entering at the bottom and moving upward. The optional needle valve allows economical control of flow and helps stabilize the float when media, particularly gases, are first introduced into the flow meter.
Typical Applications of the KSV
The KSV's compact footprint, direct-read simplicity, and low cost make it a versatile fit across many industries, from laboratory benches and chemical dosing lines to OEM equipment, electronics manufacturing, water treatment and filtration systems, and pilot plant test rigs.
- Laboratory and analytical instrumentation requiring precise micro-volume liquid flow control
- Chemical processing, monitoring reagent or additive dosing lines with aggressive media
- OEM equipment integration where panel-mount design and low flow ranges are required
- Electronics manufacturing, precise micro-flow control of process gases and cooling liquids
- Water treatment and filtration systems monitoring small-bore dosing or sampling streams
- Pilot plant and test rigs requiring low-cost, easy-to-read flow indication on water or air lines
Why Choose the KOBOLD KSV
Not every application needs a transmitter, a display, or a signal loop. Sometimes you just need to know the flow: accurately, reliably, and at a glance. The KSV is engineered for exactly that, stripping measurement back to a rugged, proven mechanical design that is easy to install and easy to read.
BABA Compliant American Manufacturing
As a Build America, Buy America (BABA) compliant instrument manufactured in the United States, the KSV meets federal procurement requirements for infrastructure projects. This compliance ensures eligibility for federally funded programs, including water treatment facilities, municipal systems, and government industrial operations, while supporting domestic manufacturing capabilities.
Government facilities and public utilities specify the KSV knowing it satisfies both performance requirements and procurement mandates, and it is made in the USA with fast delivery from KOBOLD's Pittsburgh facility.
Important Notice: Transitioning to U.S. Manufacturing
Due to the ongoing implementation of EU Directive 2020/2184 that restricts brass materials, product availability is subject to change at any time. We are actively reshoring production of our brass flowmeter models to U.S. facilities to ensure continued supply. Not all products can/will be reshored.
During this transition, stock availability may fluctuate between the time of quotation and purchase order placement. We appreciate your patience as we work to establish our domestic supply chain and remain committed to providing you with the same high-quality products made closer to home.
Common Questions about KSV - Economical Micro Flow Meter
Six water-calibrated ranges span 0.04...0.4 GPH at the low end and reach 2...20 GPH at the top, while air-calibrated ranges cover 0.3...3 SCFH through 10...100 SCFH, according to the datasheet. Each range is paired with a glass, stainless steel, or titanium float chosen to match that measuring span.
Maximum operating pressure is 87 PSI, per the datasheet, and both available material combinations carry a temperature rating of -4...248°F (-20...120°C). For hygienic or high-heat cleaning needs, the datasheet additionally lists a maximum sterilization temperature of 250°F (121°C) for the meter.
Every KSV connects through 1/8 inch NPT female threads, according to the datasheet. Fittings come in brass with NBR O-rings (material combination III) or 303 stainless steel with FKM O-rings (material combination IV), letting you match connection metallurgy and seal compound to the process media.
No. Like all needle valves, the KSV's integrated valve throttles flow but cannot fully isolate the line. When positive shutoff is required, the datasheet recommends adding a separate shutoff valve upstream of the meter. The valve's primary job is regulating flow and steadying the float during operation.
Take the reading at the upper edge of the ball, per the operating manual. As media passes through the tapered metering tube, the float settles at a height proportional to flow, and the value is read where the ball's top edge lines up with the printed scale.
Install the meter vertically so flow enters from below and travels upward, per the operating manual. Keep the instrument free of mechanical stress, add support bracing if necessary, protect the measuring tube from external damage, and avoid pressure peaks caused by sudden surges or stoppage of flow.
The operating manual cautions that exceeding the measuring range by more than 20 percent can lead to bearing damage and substantial measuring errors. Size the meter so normal operation stays on the calibrated scale, and use the needle valve or upstream controls to hold flow within range.
Yes. KOBOLD builds the KSV in the United States to satisfy Build America, Buy America requirements, which supports eligibility on federally funded infrastructure work such as municipal and water treatment projects. Public utilities and government buyers can specify it to meet domestic procurement mandates.
The datasheet rates the KSV at ±6% of full scale accuracy with ±1% of full scale repeatability. Every unit ships calibrated for its service medium, water or air, so direct scale readings hold without density corrections, keeping repeat measurements dependable for dosing and process control work.