The KOBOLD DIG is a rotating vane flow indicator that provides reliable visual confirmation of liquid flow in piping systems where flow indication is required without measurement capability. A high-visibility orange polypropylene vane wheel rotates as fluid passes through the housing, giving operators immediate visual feedback on flow status at a glance.
Available with brass, stainless steel, or polypropylene housings, the DIG covers water flow ranges from 0.13-3.2 GPM up to 0.79-21 GPM with 1/8" to 1" NPT connections, operates at pressures up to 230 PSI, and is made in the USA at KOBOLD's Pittsburgh, Pennsylvania facility in full compliance with Build America, Buy America Act (BABA) requirements.
DIG Flow Indicator Specifications
The DIG accommodates flow ranges from 0.13-3.2 GPM to 0.79-21 GPM for water-based liquids. Maximum operating pressure is 230 PSI (16 bar) for brass and stainless steel housings and 100 PSI (7 bar) for polypropylene housings, and maximum operating temperature is 176°F (80°C) across all material combinations.
- Five flow ranges (GPM water): 0.13-3.2, 0.26-6.6, 0.53-12, 0.53-13, and 0.79-21
- Connections: 1/8", 1/4", 1/2", 3/4", and 1" NPT threads
- Pressure drop at maximum flow: only 14.5 PSI, helping reduce energy consumption in pumping systems
- Media category: liquid
Housing Materials and Series Options
The DIG series offers three material configurations: the DIG-11 with brass housing and NBR seals, the DIG-14 with stainless steel (1.3955) housing and FKM seals, and the DIG-18 with polypropylene housing and NBR seals. Every version uses a polypropylene vane wheel rotating on a ceramic axle beneath a polysulfone cover.
The brass DIG-11 is suitable for general water and compatible liquid applications, while the stainless steel DIG-14 serves a wide variety of media. The all-plastic DIG-18 is the non-metallic option, designed for mildly corrosive chemicals and other compatible media, so a housing can be matched to both corrosive and non-corrosive fluids.
Made in the USA and BABA Compliant
The KOBOLD DIG rotating vane flow indicator is made in the USA and fully compliant with Build America, Buy America Act (BABA) requirements. Manufactured at KOBOLD's Pittsburgh, Pennsylvania facility, this domestically produced flow indicator meets federal mandates for infrastructure projects, water treatment facilities, and public works applications funded by federal dollars.
Applications for Rotating Vane Flow Indicators
The DIG serves industries that need simple, dependable verification of flow presence: water treatment and distribution systems use it to monitor flow at critical points without the complexity of electronic flow measurement, while HVAC systems, cooling water circuits, industrial machinery, and equipment manufacturing operations specify it for visual flow confirmation during operation and maintenance.
Its continuously rotating vane wheel is particularly useful with clear or colorless fluids, where flow can be difficult to observe through static sight windows that have no moving elements. Compared to ball-type sight flow indicators, flap indicators, or passive sight glasses, the rotating paddlewheel mechanism provides clearer indication of flow movement and direction.
Installation of the DIG Flow Indicator
The DIG installs into standard NPT threaded piping and can be mounted in any position, with flow always in the direction indicated by the arrow marking. No straight pipe runs are required before or after the indicator, and its compact dimensions and multiple connection sizes enable retrofitting into existing piping systems without major modifications.
Thread sealant, such as Teflon tape, is recommended for leak-free operation, and the operating instructions recommend mechanically securing the inlet and outlet lines approximately 2 in (50 mm) from the connections. Per the manual, flow capacity should not be exceeded by more than 20%, as exceeding it will damage its bearings.
Flow Indication vs. Flow Measurement
Flow indicators like the DIG are designed to provide visual confirmation of flow presence and relative flow activity, not to measure or quantify flow rates. This makes the DIG ideal for applications where operators need to verify that flow is occurring without requiring precise flow rate data from an electronic flow meter.
To learn more about flow indicators, please visit our in depth article about Flow Indicators.
Understanding Flow Indicators Versus Flow Meters
Flow indicators like the DIG are designed to provide visual confirmation of flow presence and relative flow activity, not to measure or quantify flow rates. This distinction makes flow indicators ideal for applications where operators need to verify that flow is occurring without requiring precise flow rate data. For applications requiring flow rate measurement, totalizing, or process control outputs, electronic paddle wheel sensors or other flow measurement technologies would be specified instead.
The DIG rotating vane flow indicator fills the need for simple, reliable, maintenance-free flow indication in systems where visual confirmation is sufficient and electronic measurement is unnecessary or cost-prohibitive.
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 DIG - Rotating Vane Flow Indicator
A vane wheel rotates on an axle shaft in accordance with the flow passing through the housing; the presence or absence of rotary motion shows whether there is flow. In the KOBOLD DIG, the orange polypropylene wheel is designed to be clearly visible through the transparent polysulfone cover.
According to specifications, the DIG is offered in five ranges for water: 0.13-3.2 GPM, 0.26-6.6 GPM, 0.53-12 GPM, 0.53-13 GPM, and 0.79-21 GPM. The range appears in the model number; for example, DIG-1435G covers 0.79-21 GPM in stainless steel.
The DIG uses NPT threaded connections from 1/8" to 1". The connection is designated by the ordering-code suffix: N06 = 1/8" NPT, N08 = 1/4" NPT, N15 = 1/2" NPT, N20 = 3/4" NPT, and N25 = 1" NPT, giving five sizes across the series.
Brass (DIG-11) and stainless steel (DIG-14) housings are rated to a maximum of 230 PSI (16 bar), while the polypropylene DIG-18 is rated to 100 PSI (7 bar). All three material combinations share a maximum operating temperature of 176°F (80°C), according to specifications.
The polypropylene-housed DIG-18, with NBR seals, is the non-metallic version intended for mildly corrosive chemicals and other compatible media. For a wide variety of media, the stainless steel DIG-14 with FKM seals is offered; the brass DIG-11 with NBR seals suits general water service.
Yes. The DIG is manufactured at KOBOLD's Pittsburgh, Pennsylvania facility and is fully compliant with Build America, Buy America Act (BABA) requirements, which makes it suitable for federally funded infrastructure, water treatment, and public works projects that mandate domestically produced components.
Yes - the DIG can be mounted in any position, provided flow runs in the direction indicated by the arrow marking on the housing. No straight pipe runs are needed upstream or downstream, and thread sealant is recommended on the NPT connections for leak-free operation.
No. The DIG is a flow indicator: it is designed to confirm flow presence and relative flow activity visually, not to measure or quantify flow rate. Applications that require actual flow readings or totalization call for a flow meter rather than an indicator.
The operating instructions caution that exceeding the device's rated capacity by more than 20% will damage its bearings. Before installation, confirm that the actual throughput of the system matches the scale range of the device, which is indicated on the nameplate.