A High-Performance Alternative to he Orifice Plate

The orifice plate and other devices for differential pressure (DP) flow measurement have both positive and negative attributes. WIKA’s innovative FlowPak features all the benefits of traditional DP flow meters but with greater accuracy and less drop in pressure. What’s more, the FlowPak does not require straight piping, making it ideal for applications with limited mounting space.

There’s no doubt that traditional differential pressure (DP) flow meters have their drawbacks, namely, pressure drops, a limited flow range, and the need for significant upstream and downstream piping. However, traditional flow measurement devices – the orifice plate, annular orifice, flow nozzle, and wedge flow meter, to name a few – have many advantages. They work well in large-diameter pipes, at high temperatures and high pressures, and with steam and other applications where other technologies may fail short in terms of cost, size, or reliability. For example, orifice plates are easy to install and maintain, and they provide repeatable measurements – even when used in viscous or dirty media. Also, an orifice plate’s maximum operating temperatures and pressures are limited only by its material and the flange.

What if you could have an instrument with all the advantages of traditional DP flow measurement devices but without the drawbacks? That’s exactly what WIKA set out to do.

Improvement on the Orifice Plate: Innovation in flow meter technology 

Based on an optimized Venturi tube design and using the latest in flow conditioning technology, WIKA’s flow specialists developed the FlowPak flow meter. It has a significantly smaller permanent pressure drop than orifice plates, nozzles, and Venturi tubes. The minimum pressure loss of the FlowPak results in almost no negative effects on the flow profile. With better energy efficiency comes lower operating costs.

FlowPak’s innovative design offers:

  • An accuracy of ± 0.5% (± 0.25% with calibration)
  • A constant flow coefficient (Cv) of 0.985
  • A permanent pressure loss of only 15–20% of the generated DP
  • No straight piping requirement

Extensive laboratory tests and field runs confirm the FlowPak’s superior performance. More than 1,500 calibration points from Worcester Polytechnic Institute’s Alden Research Laboratory, the oldest continuously operating hydraulic lab in the U.S., prove the constancy of FlowPak’s Cv– within ± 0.5% of the predicted value – regardless of the Reynolds number (Re). Its installation does not require any straight upstream or downstream piping. Even two 90° elbows out of plane are not a problem. This feature makes FlowPak the best differential pressure instrument on the market for measuring flow in applications where mounting space is limited. 

It is ideal for highly accurate flow measurements in: 

  • Gases, steam, and liquids with a Re as low as 200,000
  • Applications that work at high temperatures and high pressures
  • Applications with tight spaces or short available straight lengths

The FlowPak can be painted, covered, and treated as any other piece of piping. It is available in several materials – carbon and stainless steel, duplex steel, nickel alloys (Monel®, Inconel®, etc.) – and a variety of sizes for lines, from DN50 to DN1200. This high-performance flow meter is optimized for natural gas, gasoline, oil, oxygen, hydrogen, LNG, and most chemicals, and meets the needs of a broad range of applications in many industries.

Thanks to its wide product portfolio, one of the largest amongst PFC manufacturers worldwide, WIKA offers a variety of instruments to measure and monitor flow, ranging from the simplest Model FLC-OP orifice plate-up to our high-accuracy FlowPak flow meter. Contact a WIKA specialist to discuss which solution is right for your application.



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