Imperial Flange and Fitting   P.O. Box 352262  Los Angeles, California 90035 (USA)

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Imperial manufactures a complete line of differential pressure ASME Herschel type venturis. Imperial venturis are in operation in petrochemical, refining, gas pipeline, water sewage and power plants. Venturi tubes are used whenever low pressure loss, high accuracy, short straight piping or high-solids fluids are encountered.  ASME Herschel-type venturi tubes have been universally accepted as the most efficient primary device available. No other type of venturi or flow tube design has been more thoroughly researched, tested, and proven than the ASME type.

Each Imperial venturi is designed and manufactured for a specific beta ratio or throat diameter to meet differential pressure and flow requirements. Due to the extent of published research on venturis, Imperial is able to provide venturis with 0.75% accuracy without the need for laboratory flow calibration. This high accuracy is sustained indefinitely since there are no sharp edged protrusions to wear. Also, a new approach is used to attach upstream and downstream cones to the throat to manage the best possible velocity profile in the venturi throat. Imperial venturi tubes are designed to be economical, lightweight, versatile, non-corrosive, and accurate to meet the customer's needs.

Due to the low pressure loss, a venturi saves the user many dollars and frequently pays for itself in one year of continuous operation by greatly reducing pumping cost. If lower pressure loss is required please consider the flow tube or our TA2% low  loss design.

For fluid containing solids, such as sewage or slurry, Imperial venturis can be equipped with cleanout rods on the pressure taps for periodic cleaning when required. Imperial venturi meters are manufactured from carbon steel, chromalloy steel, stainless steel, monel, nickel, bronze, hastelloy, fiberglass, PVC and other materials to suit specific applications. A fabricated venturi is more durable than a cast venturi yet weighs considerably less, which results in a lower shipping cost and easier installation.

The text ASME Fluid Meters recommends a certain length of straight pipe upstream of a venturi meter to ensure accurate flow measurement. If it is impossible to meet the recommended lengths, with or without straightening vanes, Imperial venturis utilizing a piezometer ring or averaging annulus can be provided to reduce measurement error.

Along with venturi meters, Imperial Flange manufacturers ejectors, eductors, and differential pressure transmitters.

Utah Water Research Laboratory Calibration Report

Click on the pages from our venturi tube manual or scroll down page to see enlarged images:



General Info

General information



36" Venturi

36-inch venturi flow meter

more 36"

Additional 36-inch specs

V-10, V-15, SV-10


VI30 Specs

VI-30 Specifications

Dimensions & Capacities

Dimensions and Capacities

Venturi Tube

Venturi Meter

Venturi Flow

Venturi Flow Meter


Venturi Tubes

Venturi Meter

Venturi Flow Meter