The KOBOLD DVE is a multivariable insertion vortex flow meter that measures the mass flow rate of steam, gases and liquids through a single line penetration. Depending on the model, it combines a vortex shedding velocity sensor, an RTD temperature sensor and a solid-state pressure transducer in one probe, measuring flow, temperature and pressure at the same point.
How the DVE Insertion Vortex Flow Meter Measures Mass Flow
A shaped bluff body in the sensor head generates a Karman vortex street as fluid passes it. A piezoelectric sensor behind the bluff body senses the small pressure differences these vortices create. The number of vortices is directly proportional to flow velocity and is converted into a frequency signal; a Pt1000 RTD measures temperature and a solid-state transducer measures pressure.
External pressure and temperature taps may not provide adequate compensation when process conditions change between the velocity measurement point and the tap locations. Because the DVE measures every parameter at one location, it is designed to deliver a more accurate process measurement, and a single line penetration also simplifies the system.
DVE-V, DVE-T and DVE-P Model Options
The DVE-V delivers a direct reading of volumetric flow rate and is designed as a cost-effective choice for most low-viscosity liquids. The DVE-T adds a Pt1000 RTD to output a temperature-compensated mass flow reading and is typically used for saturated steam. The DVE-P adds a pressure sensor and provides flow computer functionality in a compact field device.
The DVE-E and DVE-M options add real-time energy monitoring.
Line Sizes, Process Connections and Installation
The DVE insertion probe fits pipes from 2" to 24" (DN50 to DN600). Process connections are 2" NPT male or 2" ANSI 150, 300 or 600 lb flanges (DN50 PN16, PN40 or PN64), with either a compression fitting or a packing gland probe seal. Packing gland versions can be ordered with a retractor for insertion and removal under line pressure.
The entry port needs a minimum 1.875" (47.63 mm) internal diameter, and the probe must be perpendicular to the pipe within ±5° with the alignment pointer facing downstream. The sensing head sits at the pipe centerline for pipes DN250 (10") and smaller, or 5" (127 mm) from the inner wall in larger pipes. Pressure drop across the probe is negligible. Probe lengths are compact, standard or extended, and electronics mount on the probe or remotely with up to 49 ft (15 m) of cable.
Pressure, Temperature and Accuracy Ratings
The DVE is rated to a maximum pressure of 100 bar absolute (1,450 psia) and a standard process temperature range of -328°F to 500°F (-200°C to 260°C). A high-temperature version extends the range to 752°F (400°C). The stem, sensor head and compression fitting are rated PN100; the packing gland is rated PN64 (600 lb).
Volumetric flow accuracy is ±1.2% of reading for liquids and ±1.5% for gases and steam. Mass flow accuracy is ±1.5% and ±2.0% of reading respectively, based on 50 to 100% of the pressure sensor range. Temperature accuracy is ±2°F (±1°C) and pressure accuracy is ±0.3% of full scale. Turndown is application dependent and can exceed 100:1. Ambient temperature is -40°F to 140°F (-40°C to 60°C).
Power, Outputs, Display and Approvals
Power options are 12-36 VDC loop powered 2-wire (DVE-V), 12-36 VDC 4-wire at 300 mA maximum, or 85-240 VAC 50/60 Hz. Volumetric meters provide one 4-20 mA output, one totalizer pulse and HART. Multivariable meters provide up to three 4-20 mA outputs (mass flow, volumetric flow, temperature, pressure or density), three alarms, one pulse and HART, with Modbus optional.
The 2-line, 16-character alphanumeric LCD rotates in 90° steps, and six pushbuttons allow full field configuration. The enclosure is rated IP66 (NEMA 4X) with two 3/4" NPT ports. Wetted parts are 316L stainless steel (1.4404); packing is Teflon®, or graphite on high-temperature versions. The DVE carries ATEX and IECEx approvals (Ex d IIB + H2 T6), and a 3.1 material certificate and NACE conformance are available as options.
Inline Alternatives: DVZ and DVH Vortex Flow Meters
For applications best suited to an inline installation, KOBOLD offers two alternatives. The DVZ compact inline vortex flow meter offers flow measurement, switching and batching capabilities. For more rigorous applications and multivariable measurement, consider the DVH inline vortex and multivariable flow meter.
Application Guide Required for Product Specification
This product requires completion of our Application Guide before specification and ordering. Unless this is a repeat order of a previously specified product with KOBOLD, we cannot accept orders or provide quotations without a completed Application Guide. Every DVE is calibrated and configured for your flow application.
- Complete the Application Guide: provide detailed information about your specific application
- Technical review: our engineering team reviews your requirements
- Product specification: we specify the exact configuration for your needs
- Quotation and ordering: receive your custom quote with precise part numbers
Common Questions about DVE - Multivariable Insertion Design Vortex Flow Meter
Steam flowing past the probe tip sheds alternating vortices from a bluff body, and a piezoelectric element detects the resulting pressure pulses. The vortex frequency rises in direct proportion to velocity, so the electronics calculate volumetric flow from that frequency. On the DVE-T and DVE-P, built-in temperature and pressure readings convert this to compensated mass flow.
The DVE covers line sizes from 2" up to 24" (DN50 through DN600). The probe enters the line through a 2" NPT or 2" (DN50) flanged connection rather than replacing a pipe section. The sensing head is positioned using an insertion length formula that accounts for connection height, pipe wall thickness and pipe inside diameter.
Yes. The packing gland probe seal with a retractor is the hot tap configuration and can be removed under line pressure. An insertion tool is required whenever the meter is inserted at more than 50 psig; without a retractor, the packing gland version is limited to 50 psig (3.5 bar). Compression fitting versions are permanent once the fitting is tightened.
Typical saturated steam ranges run from 205 to 2,721 lb/h in a 3" line at 5 psig, and up to 52,942 to 3,346,615 lb/h at 24" and 500 psig. Gas and steam velocity reaches 300 ft/s (90 m/s); liquids run 1 to 30 ft/s (0.3 to 9 m/s). Precise flow depends on fluid and pipe size; consult the factory.
Five full-scale ranges are available: 30, 100, 300, 500 and 1,500 psia (2, 7, 20, 35 and 100 bar abs), with over-range limits of 60, 200, 600, 1,000 and 2,500 psia. To maximize accuracy, specify the lowest full-scale range that covers the application. The maximum working pressure of a DVE-P can be limited by the pressure sensor range selected.
Yes. HART is included with the 4-20 mA output on both volumetric and multivariable versions, and Modbus process monitoring is available as an ordering option (output codes M and 4). The totalizer pulse output for remote totalization is a 50 ms solid-state relay pulse rated 40 VDC. All outputs are optically isolated and require external power.
Yes. Approvals are ATEX II 2G Ex d IIB + H2 T6 and II 2D Ex tD A21 IP66 T85°C, plus IECEx Ex d IIB + H2 T6 and Ex tD A21 IP66 T85°C, for ambient -40°C to +60°C. The six buttons can be operated through the sealed enclosure with a hand-held magnet, so certification is not compromised.
Upstream straight run depends on the disturbance: 10 pipe diameters after a 90° elbow or reduction, 15 after two elbows in one plane, 20 after an expansion, and 25 after two out-of-plane elbows or a partially open valve. Five diameters are required downstream in every case. For liquids in vertical pipes, install with flow upward so the pipe stays full.
Any gas, liquid or steam compatible with 316L stainless steel. The DVE-V covers liquid flow monitoring from general water flows to hydrocarbon fuel measurement, the DVE-T is typically applied to saturated steam, and the DVE-P handles gas, liquid and steam mass flow. The meter is not recommended for multi-phase fluids, and oxygen service requires the optional oil- and grease-free cleaning.
Yes, with the DVE-E or DVE-M option. The meter monitors one leg of the process, supply or return, and uses a second temperature sensor on the opposite leg to calculate energy from flow and temperature difference. It can be programmed for steam, hot water or chilled water, with units including Btu and watt-hours. Not approved for custody transfer.
Product Specifications
Process Connection
2" NPT Male or 2" ANSI 150/300/600 lb (DN50 PN16/40/64) Flange, via Compression Fitting or Packing Gland
Line Sizes
DN50...DN600, (2"...24")
Wetted Materials
316L St. Steel
Input Power
12-36 VDC (2 & 4 Wire), 85-240 VAC 50/60 Hz
Display
Alphanumeric 2 Line x 16 Character LCD
Media Categories
Liquid, Gas, or Steam
Product Features
Optional Integrated Temperature and Pressure Sensor
Field Configurable Range, Outputs and Display
High Temperature Version to 400 °C
High Pressure Version to 100 bar abs (1,450 psia)
Certifications/Approvals: ATEX, IECEx
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