The KOBOLD DKF is a rotary paddle-wheel flow indicator that lets operators
confirm low-viscosity liquid flow at a glance. A bright red paddle wheel spins
inside a clear borosilicate glass dome, turning fluid movement into an obvious
visual signal for water, coolant, and process-fluid lines.
How the DKF Shows Flow at a Glance
The DKF indicates flow mechanically: passing liquid turns a bright red paddle
wheel housed beneath a domed borosilicate sight glass, so movement is visible the
moment fluid runs. The domed glass gives full 360-degree visibility from above,
letting operators verify flow from elevated or angled vantage points. Because
indication is purely visual, the DKF needs no power, wiring, or output signal to
do its job.
Built for Low-Viscosity Liquids
The DKF is designed for low-viscosity liquids such as water, coolants, and
process fluids. Its bright, high-contrast paddle wheel provides a clear advantage
over indicators that rely on subtle float movements or internal parts that are
hard to see, making flow confirmation quick and unambiguous even at a distance.
Horizontal or Vertical Installation
The indicator installs in either horizontal or vertical pipe runs, so it fits a
wide range of piping layouts. The domed sight glass provides 360-degree
visibility, and the paddle wheel stays easy to read regardless of mounting
orientation. Connections use 1/8-inch to 1-inch NPT threads. For reliable service,
support the piping rigidly at the inlet and outlet with pipe clamps, align fittings
to avoid piping-induced stress, and avoid pressure surges such as those from fast
start-up or pulsating flow.
Materials and Construction
The DKF uses a brass housing and retaining ring, a borosilicate glass dome, a
brass axle, and stainless steel screws. Two versions cover different media needs:
the DKF-31 pairs a POM paddle wheel with EPDM seals, while the DKF-32 pairs an
ETFE paddle wheel with FKM seals. Both share the same brass body and glass dome.
Flow Range, Pressure, and Temperature
The DKF measures water flow from 0.04–0.5 GPM up to 0.50–22.0 GPM depending on
fitting size, across 1/8-inch to 1-inch NPT connections. It operates at pressures
up to 87 PSIG and temperatures up to 248°F (120°C), with a pressure drop of about
15 PSI at maximum flow.
Model Options and Ordering
Each flow range corresponds to a specific NPT size and model number—for example,
the 1/8-inch DKF-3106 (0.04–0.5 GPM) through the 1-inch DKF-3125 (0.50–22.0 GPM) in
the DKF-31 series, with matching DKF-3206 through DKF-3225 codes in the DKF-32
series. Unit weights range from about 0.62 to 3.1 lbs.
Made in the USA and BABA Compliance
The DKF is made in the United States, and BABA (Build America, Buy America Act)
compliant models are available for projects with domestic-content requirements. US
manufacturing also supports quick delivery, making the DKF a practical choice where
domestically sourced components must be specified.
Common Questions about DKF - Rotary Paddle Wheel Flow Indicator
Liquid moving through the body spins a red rotor mounted under a domed glass
window. Operators read flow directly by watching the rotor turn—faster rotation
means faster flow. No gauges, scales, or electronics are involved; the rotating
wheel itself is the indication, readable from any angle above.
The DKF is offered in six sizes spanning 1/8-inch to 1-inch NPT threads.
Corresponding water flow ranges run from 0.04–0.5 GPM on the smallest fitting to
0.50–22.0 GPM on the 1-inch fitting, so you can match the unit to your line size
and expected flow.
According to its specifications, the DKF handles pressures up to 87 PSIG and
media temperatures up to 248°F (120°C). Expect roughly 15 PSI of pressure drop at
maximum flow. Staying within these limits protects the sight glass and internal
parts and keeps the warranty valid.
The DKF suits low-viscosity liquids—water, coolants, process fluids, and other
compatible media. Two material builds widen compatibility: EPDM seals with a POM
wheel on the DKF-31, or FKM seals with an ETFE wheel on the DKF-32. Choose the seal
and wheel materials that match your fluid.
Yes. It works in both vertical and horizontal runs, giving flexibility in tight
or unconventional layouts. For dependable operation, secure the piping firmly with
clamps at both ports, keep fittings aligned to prevent induced stress, and shield
the unit from impact and from surges caused by rapid valve action.
Both share a brass housing, brass axle, borosilicate dome, and stainless steel
screws. What changes are the wetted parts. On the DKF-31 the rotor is POM and the
seals EPDM; on the DKF-32 the rotor is ETFE and the seals FKM. Pick the version
your fluid is compatible with.
Yes—the DKF is built in the USA. Configurations meeting the Build America, Buy
America Act (BABA) are offered for work that must use domestically produced parts,
such as federally funded infrastructure. Because the units are produced
domestically, lead times are typically short. Request the BABA option when
ordering.
No. The DKF is a mechanical, sight-based indicator with no electrical
connections listed in its specifications. Flow itself drives the visible rotor, so
there is nothing to wire, power, or calibrate. That makes it a simple,
low-maintenance way to confirm that liquid is actually moving through a line.
At maximum rated flow, the DKF introduces about 15 PSI of pressure drop,
according to the datasheet. Actual drop is lower at partial flow. Factor this
figure into pump and system-pressure calculations, and keep operating pressure
within the 87 PSIG maximum to stay inside the indicator's rated limits.
Match your required flow range and NPT size to the corresponding model number.
In the DKF-31 series that runs from the DKF-3106 (1/8-inch, 0.04–0.5 GPM) to the
DKF-3125 (1-inch, 0.50–22.0 GPM); the DKF-32 series mirrors this as DKF-3206
through DKF-3225. Units weigh between about 0.62 and 3.1 lbs.
Product Specifications
Indicating Range
0.04...0.5 GPM to 0.50...22.0 GPM
Fittings
1/8...1 NPT Thread
Max. Temperature
248 °F (120 °C)
Product Features
Horizontal or Vertical Installation
BABA (Build America, Buy America) compliant models available
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