BIF Venturi Flow Meter

Builders Iron Foundry Venturi Meter stated purpose at incorporation was the “manufacture of iron facades for houses and other castings for builders and other uses.” Examples of ornamental iron work produced by BIF during the mid-1800’s can still be seen on the Library of Congress Building in Washington. Other products produced by BIF during that period included cylinders for bridge piers and prefabricated lighthouses, which were installed around the world.

About Builders Iron Foundry

Almost 200 years have passed since the High Street Furnace Company produced its first iron plow. Its successor, BIF, has successfully designed, manufactured, and marketed a steadily evolving product line for over 13 decades. Today BIF, specializes in the design and supply of venturi meters, rate-of-flow controllers, and metering accessories. Combining our expertise, and thousands of installations, BIF can meet your application requirements.

In 1887, Clemens Herschel introduced the Herschel Standard Venturi, by far the most accurate flow meter available over the ensuing 100 years. In 1893, the Chief Engineer at BIF, F.N. Connet, perfected the necessary metering instruments to enable use of the BIF Venturi tube as a flow measurement tool. It’s been over 40 years, since the development of the UVT, but it’s design is still the standard all other venturi meters should be compared to. While others have attempted to copy the UVT’s hydraulic shape, only BIF has the knowledge, experience and years of development and testing to stand behind it.

Venturi tubes and meters have been two of BIF’s most important products ever since. A continuing dedication to upgrading these products led to BIF’s research and development of the Universal Venturi Tube™ in 1970. At the time of its introduction, the UVT™ was the result of thousands of hours of design engineering and rigorous hydraulic testing. The UVT greatly increased the reliability and accuracy of flow measurement. At the same time, the UVT reduced costs of both lead-in piping and surrounding structures by eliminating the previous requirement for long runs of straight pipe into a Venturi.

The Products of Builders Iron Foundry

Based on experience gained from over 100 years in the flow measurement industry, BIF has developed a unique line of products to serve your needs. Through extensive R&D BIF developed the Universal Venturi Tube (UVT). The UVT is a unique, differential producing primary element for accurately metering flow. Several models are now available, each produced following UVT design for accurate, reliable measurement of flow.

Builders Iron Foundry Venturi Meter Products
Builders Iron Foundry Venturi Meter Products

Venturi Meters

A “true” venturi meter has static pressure taps at both the inlet and throat sections. A static pressure tap senses the pressure in a cylindrical area where the flow is not changing direction and is parallel to the pipe wall. This unique shape conditions the flow in the transition section to provide a more uniform velocity profile in the throat. These hydraulic design features result in very accurate, reliable, and wide-ranging flow measurements.

The UVT has a cylindrical inlet with a static pressure tap, a transition section employing two constriction angles of 40° and 7° to condition the flow, and a cylindrical throat section of sufficient length to install a static pressure tap.

This unique design provides the advantages of a “true” venturi meter at reasonable cost, not previously possible in differential pressure primary meters. Unlike flow tubes on the market, the BIF modified Venturi design utilizes our documented and extensively tested corner inlet tap. Slightly reducing the installed accuracy in favor of greater flexibility and cost savings, for the many applications that can benefit from or require these features.

The BIF corner tap design performance, however, unlike flow tubes, adheres to all other “true venturi“ principles. The UVT offers a true static pressure tap at the throat location, inlet flow conditioning, and an otherwise full hydraulic shape, well known and proven, thereby continuing to offer all other benefits of the Universal Venturi Tube.

The BIF Universal Venturi Tube is the most accurate flow measuring primary element available for the vital measurements of water and wastewater. Extensive, long term testing and calibration have enabled BIF to guarantee the accuracy of each UVT.

BIF Model 20181 Cast Iron Venturi

The Model 20181 Universal Venturi Tube is a short laying length, differential producing, primary element. The 20181 was originally designed for water and sewage, but it works equally well in other applications. The Cast Iron UVT features an uncalibrated accuracy of ±0.5% and a warranty of 25 years.

The Model 20181 Universal Venturi Tube (UVT) is a differential producing, primary measurement device for accurately metering water, sewage, air and other fluids for both municipal and industrial applications.

The Model 20181 Cast Iron venturi is a multipurpose, short laying length, efficient and economical device that is time proven and unmatched in the industry. It’s genesis is the clear leader for proven, substantiated, and documented performance.

The BIF Model 20181 Universal Venturi Tube (UVT®) is a highly accurate differential producing primary element for measuring Water, Waste Water, Gases, Air and many other fluids, for municipal and industrial applications.

The Universal venturi Tube is a multipurpose, short laying length efficient and economical primary element device. The UVT is time proven and its performance is unmatched in the industry. It is the clear and outstanding leader for proven, substantiated and documented performance.

The Model 20181 with its high enduring accuracy of ±0.5% of actual flow rate, has been established and proven by thousands of laboratory trials, and is ensured by it’s rugged, durable and self-scouring construction.

Wide flow ranges are possible because of the constant discharge coefficient (C). The secondary differential pressure instrumentation is typically the limiting factor in determining flow rate range and turndown capabilities. Low head loss is assured by the efficient truncated pressure recovery cone designed into the venturi. This truncated cone allows for the venturi’s short flange to flange length, thus minimizing the installation space for the meter.

The proven UVT Hydraulic profile conditions the flow profile as it enters the venturi so that differential signal is stable and predictable. This profile is also responsible for the overall performance of the Universal Venturi Tube.

Annular chambers at the high and low pressure taps are no longer needed thus avoiding concerns about collection of solids and sediments and their associated maintenance concerns. No in-line or on-line calibration is ever required for this primary element

The metering design shall be a differential pressure producing type, utilizing pure static pressure sensed at the inlet and throat. The differential pressure shall indicate static pressure change only.

The entrance section shall be a cylindrical section of similar diameter as the pipe in which
the meter is being installed. The high-pressure tap shall be installed in this entrance section.
Vent and drain ports shall be included in the venturi entrance section on a 90 degree plane to
metering taps.

The throat section shall be a cylindrical section with a length at least 0.50 times the throat diameter. The low-pressure tap shall be installed in the throat section. The pressure recovery section (outlet cone) shall be truncated and have an included angle of 10 degrees.

The metering element shall not have debris collecting cavities or annular chambers, and shall have a single pressure connection at the inlet and throat on the horizontal centerline. The flow meter body shall be constructed of cast iron ASTM A126 Class B. The throat liner and pressure tap bushings shall be Type 316 Stainless Steel. The flow meter flanges shall be ANSI Class 125 Flat Faced.

.The flow meter shall be hydrostatically tested at twice the working pressure for a period of not less than 10 minutes. Hydrostatic testing of venturi shall be performed at the factory by placing the body in tension using blind flanges to seal the ends of the venturi. Hydrostatic testing by the use of internal presses to simulate hydrostatic pressure is prohibited.

The entire flow meter except the throat liner, flange faces and pressure tap bushings shall be coated with epoxy paint that meets the requirements of the United States EPA, and is NSF 61 approved for potable water applications.

Coefficient values and tolerances shall be based on actual calibrations, performed by a hydraulic
laboratory, with standards traceable to NIST and in conformance with standard calibration protocol

The substantiation data shall indicate that the venturi meter discharge coefficient is independent of line size and beta ratio. In addition, the test data shall prove that the coefficient remains constant over the range of Reynolds Numbers and down to 75,000.

Test results from the calibration of at least 30 hydraulically similar meters used for this substantiation shall show that the discharge coefficient 2 times standard deviation is no greater than ±0.5 percent.

Effects of upstream piping configuration shall be known and based on testing performed by a
recognized hydraulic laboratory. Substantiation shall show headloss as a function of the velocity head expended.


  • Available Sizes from 4″ to 60″
  • 316 Stainless Steel Throat Material Standard
  • Flange Ratings Meeting ANSI Standards
  • Interior Surfaces Coated with Universal Epoxy Coating Meeting ANSI/NSF-61 Standard
  • Accuracy of ±0.5% of actual flow rate (Uncalibrated)
  • Calibrated Accuracy’s of ±0.25% of actual flow rate available

FRP (Fiberglass Reinforced Plastic) UVT – Model 20182

  • Single Piece Molded FRP (Fiberglass Reinforced Plastic) Standard
  • Uncalibrated Accuracy of 0.75% of Actual Flow Rate
  • Multiple Configurations / Sizes Available
  • Special Throat / Flange Materials Available on request

The Model 20182 Universal Venturi Tube can be ordered in all FRP construction or with a stainless-steel throat section. It features the same high accuracy as the Model 20181, but is lighter weight, lower cost and easier to install.

The Model 20182 Fiberglass Reinforced Plastic (FRP) Insert Universal Venturi Tube (UVT) is a differential-producing, primary-flow, metering element designed to accurately measure water, air, gases, acid solutions, alkali solutions and slurries, where low head loss and high accuracy is desired.

Standard venturis are manufactured for basic line sizes from 4″ to 48″. The flexibility of the FRP design allows many special inlet and throat combinations to be available as standard items.

This corrosion-resistant, low-cost and lightweight UVT is manufactured entirely of fiberglass reinforced epoxy vinyl ester resin, Ashland Chemical Derakane™. This material is resistant to all the typical fluids measured and to many very aggressive fluids as well. The Derakane material is coated with a very tough and also chemical resistant gel coating. This smooth internal surface allows BIF to utilize an all FRP design in lieu of requiring a metal throat or flange. The Model 20182’s design and construction make it less expensive, longer lasting and more accurate than other technologies such as metal orifice plates.

The insert design permits installation within the pipeline flanged pipe joint. Due to the lightweight design no special equipment foundations are required beyond those required for the support of the pipe itself. The venturi’s self-scouring design ensure enduring accuracy while the rugged durable construction maintains all critical dimensions and surfaces at optimum conditions for many years of maintenance free operation.

Fabricated UVT – Model 20183

  • Standard Sizes Available
  • Multiple uses of Materials for Construction
  • Pressure Vessel / Insert / Bi-Directional / Rectangular
  • Accuracy from .5 % to 1% (Uncalibrated)

The Model 20183 features the UVT’s high accuracy, but is custom designed and built for your application. It is available in a wide range of sizes and materials for any installation. The Model 20183 can also be supplied in applications where both forward and reverse flows are possible. The Fabricated UVT can be designed as a full body pressure containing venturi, or as an insert style venturi similar to the Model 20182.

To fill the varied demands in the field of fluid measurement, BIF offers the Universal Venturi Tube (UVT) in a series of designs that allow the use of many metals in the form of rolled plate, forgings, and bar stock.

Thus, the combined advantages of power savings from low head loss, maximum accuracy, and short laying length can be obtained in metals proven best for a given application. The intermediate and larger flow tubes (generally from 8” up) are strong weldments of rolled or forged sections. Smaller tubes are machined from bar stock for customer savings, depending on availability of materials. All surfaces are precisely machined to UVT formula for accurate prediction of flow characteristic.

Rate of Flow Controllers

BIF’s line or rate of flow controllers ranges from the integral venturi and valve model 20610, to the super short laying length model 20620. Each rate of flow controller is designed for the optimal combination of flow measurement and control.

  • Line Sizes 6″ to 24″
  • Choice of Operators
  • Low Installed Cost
  • Tight Closing Butterfly Valve
  • Minimized Laying Length for Tight Fits

The BIF Model 20610 is a fourth generation rate of flow controller that utilizes the high accuracy venturi form of the BIF Universal Venturi Tube (UVT®). The Universal venturi Tube gives this rate of flow controller a high metering accuracy at ±0.5% of actual flow rate and also gives a very stable flow signal to aid in control loop setup and tuning. This excellent performance from the UVT also aids in giving the rate controller a high repeatability ±3% over a 4:1 flow rate range. For accuracy and repeatability your rate control system needs a BIF Model 20610 Rate of Flow Controller

The Model 20610 Rate of Flow Controller also incorporates an integral butterfly valve as the final control element. This butterfly valve is unique in the industry in that it has a designed in field adjustable and field replaceable valve seat. No more replacing the whole valve when a seat leak occurs. With the BIF valve design just adjust a couple of set screws to extrude the seat further into the waterway and the valve seals like new.

This patented BIF design also allows for quick and easy seat replacement should the seat become unserviceable to such an extent that a simple adjustment is not sufficient. The old seat is simply snapped out of its holding groove in the valve body and the new seat snapped into place. The seat configuration is so dependable that BIF warrants the seat assembly for 15 years against defects in materials or workmanship. No other valve company in North America will warrant their valve for this period.

The valve designed into the Model 20610 Integral Rate of Flow Controller is also sized for optimum controllability. This means typically that the valve is one line size smaller than the nominal inlet of the rate controller. This valve optimization puts the control in the linear control range of the butterfly valve and thus aids in quieting the control loop causing less “hunting” for the proper control point.

Combining the high accuracy UVTY with a well-designed and properly sized butterfly control valve in a short flange to flange length yields a long service life, high accuracy and high repeatability for your rate control needs. The BIF Model 20610 Integral Rate of Flow Controller.

Integral Rate of Flow Controller – Model 20610

The BIF Model 20610 is a fourth-generation rate of flow controller that utilizes the high accuracy venturi form of the BIF Universal Venturi Tube. The excellent performance from the UVT combined with an optimally sized valve, aids in giving the rate controller a high repeatability ±3% over a 4:1 flow rate range. The Model 20610 Rate of Flow Controller also incorporates an integral butterfly valve as the final control element. This butterfly valve is unique in the industry in that it has a field adjustable and replac

Separate Meter and Valve Controller Assembly – Model 20614

The Model 20614 is BIF’s solution for customers who want a tested and assembled rate of flow controller, but have standardized their plant on one valve manufacturer. This product combines the proven UVT meter design with a separate butterfly valve. Valves are sized for optimal performance. In cases where a less than line size valve is used, an adapter is assembled to the valve for easy installation. Most standard AWWA style valves can be used in the model 20614.

Short Laying Length Controller Assembly – Model 20620

The Model 20620 was designed as a direct bolt in replacement for existing BIF Model 603 Rate of Flow Controllers. The Model 603 has been in operation for decades in plants all over the world, you may have one in your plant. This is BIF’s shortest laying length flow controller. Like the Model 20614 the valve is sized for optimal performance and an adapter is assembled to the valve for easy installation.

Open Channel and Partially filled Pipe Flow

Kennison Nozzle – Model 20135

The BIF Kennison Nozzle features a non-clogging design and easy installation. It accurately measures flow over a wide range of rates.

Kennison Nozzle Applications:

  • Partially Filled Pipes
  • Open Discharge Applications
  • Flow into Tanks
  • Flow Containing Solids

Flow Monitoring and Control Station – Models 40100 and 40200

The Model 40100 monitor and 40200 control station provide local display of the flow rate as well as local control if needed.

  • Model 40100 – Flow measurement
  • Model 40200 – Flow measurement and control

Both versions include a corrosion resistant enclosure with a differential pressure transmitter, local display and power supply. With the control option a PID controller is installed along with local setpoint capability. When paired with a BIF Rate of Flow Controller and valve actuator you have a complete standalone control system.

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