Construction and design of instrumentation since 1966
Monday – Friday

8 am – 4 pm (CET)

+45 45 76 94 00

Høgevej 6

DK-3400 Hillerød

You are here: Home » Products » FLOW » Venturis, Cones & Wedge Meters » Venturi Tube » Machined Venturi Tube

EMCO Classical Venturi Tube Type KVR (Machined)


The classical venturi tube is one of the most tested and trusted flow meters on the market. Based on the ISO 5167-4 standard, it offers durable flow measurement with minimal pressure loss. 




Design and calculation standards
ISO 5167-4, ASME MFC-3M
DN 50 - DN 250, 2” - 10"
Pressure rating
PN 10 - 640, 150 - 2500 lbs, ISO PN 20 - 420
β (d/D)
Preferred range 0,4 < β < 0,75
Carbon steel, AISI 316, Duplex, 254 SMO, other on request
Mounting style
Weld ends according to DN 2559 or ANSI B16.25. Flanges acc. to DIN or ANSI B16.5 standards (Greyloc Clamp connection available on request)
Pressure taps
Weld ends Ø 21.3 mm, 26.9 mm, thread connection 3/8", 1/2" BSP, 1/2" NPT, or flanged
Single pressure tappings or 2x4 tappings each arranged with an external annular ring to equalize the pressure
Outlet cone

Technical Data

1 % (acc. to ISO 5167)
Pressure loss
Depending on outlet cone, between 10-15% of the differential pressure measured
Limits for Reynolds No
2*10^5 < ReD < 2*10^6 according to ASME


Shut-off valves
Condensing chamber unit for steam flow


The machined venturi tube must be installed in a straight cylindrical pipe without obstructions, with specific inner pipe diameter requirements. The required straight lengths vary based on beta values and the presence of bends or reducers. Full bore valves are recommended upstream, and the inner pipe wall must be clean and smooth. The Venturi tube should be centered carefully and connected to the differential pressure transmitter below it for most applications, except for gas flow. Safety devices must be in place to prevent pressure exceedance, and elevated temperatures should be avoided. Regular maintenance involves ensuring a deposit-free interior. Compliance with ISO 5167 and other standards is crucial for quality assurance.

Download the installation guide above for more detailed information. 

Who to contact?

Christoffer Thrane
Sales & Marketing Manager


Learn how we calibrate our flow meters

Calibration of a flow meter