The basic performance of square and rectangular venturi meter designs is the same as those of traditional circular venturi meters without the need to switch from rectangular to circular form. They are widely used due to their long-life expectancy, guaranteed accuracy, low energy consumption, short straight piping requirements and cost effectiveness. They offer design and engineering flexibility with end arrangements (flanged, mechanical joint, weld end, etc.) combined with various body materials and coatings to achieve pressure, temperature, flow range, line fluid, line size, laying length and cost objectives as dictated by the specific applications. For over 40 years, PFS has led the market in the design, testing and application of square and rectangular venturi meters.
Square and rectangular venturi meters can be used in a wide range of municipal, power and industrial applications. Examples of applications are:
- Municipal wastewater treatment plant influent and effluent where existing conduits are square or rectangular, thus there is no reason to convert to circular venturi meters to measure the flow.
- Steel production facilities where gas measurements on coke oven gas or hot blast gas are difficult for other technologies, such as thermal, due to the high humidity and dirty gas conditions that impair the performance of such devices.
Two application success stories are:
- A sewage treatment plant final effluent discharge application where the specified maximum headloss could not be greater than 3.0” w.c. at the max flow. PFS’s metering solution was model tested at Utah Water Research Laboratory and the tested and proven headloss was 1.6” w.c.
- A jet engine testing facility that required the accurate measurement in a square conduit of process air over a wide flow rate range. This was solved by a PFS HVT-RC meter with external tap manifolds and multi-variable differential pressure transmitters.
Meter Design and Specifications
The basic accuracy of the rectangular and square modified short form HVT venturi meter is +/-0.5% of rate above 75,000 pipe Reynolds number. We employ a combination of CFD and model testing programs for applications that are too large for independent laboratory flow calibration. The HVT performance profile offers significantly lower permanent pressure loss, so both liquid and gas applications with very low line pressure or very low-pressure loss conditions can be effectively measured using this technology.
Materials of construction are very flexible. They include cast in place concrete (a favorite on municipal influent and effluent channels) in which the inlet tap and throat section are fabricated metal and the balance of the meter profile is cast in place concrete. This is extremely cost effective with very long life expectancy and little to no maintenance.
The PFS square and rectangular venturi meters can be equipped with external pressure averaging manifolds (pictured); inspection ports; and equipped with diaphragm seals for raw sewage and contaminated flow applications.