Differential Pressure Flow Meters

Orifice Plate

Orifice plates are the simplest type of primary flow element. The bore diameter is calculated to generate the specified differential pressure at full scale flow rate. The differential pressure generated by the primary flow element is normally transformed into an electrical signal proportional to the flow rate by a differential pressure transmitter.

Our products are available with RF, FF or RTJ sealing faces.

Restriction Orifice

When a reduction of pressure or a limitation of the flow rate is required a restriction orifice must be inserted into the pipeline. Also, in high delta pressures, where a change in phase or sonic issues can occur, a complex design will be required.

The solution in these cases is to divide the delta pressure in several steps, avoiding all the issues generated by these factors. This solution is called multi-step restriction orifice.

These are evaluated on a case by case basis depending on customer requirements and flow conditions.

FlowPak Flow Meter

The FlowPak flow meter is a technological advancement in flow profile formation, redefining performance standards in critical applications. Due to the innovative design, no straight upstream and downstream pipes are required regardless of the flow profile. Installation following two 90° elbows is also possible. The pressure loss is reduced to a minimum, providing the highest energy efficiency of all flow measuring instruments, outperforming even Venturi tubes. The FlowPak flow meter is the best differential pressure measuring instrument for flow for applications with limited mounting space.

Venturi Tube

Venturi tubes are reliable, easy to use with low-maintenance and are particularly suitable for the measurement of clean liquids and gases.

The main advantages of a Venturi tube over other differential pressure flow meters are the higher pressure recovery and the lower upstream and downstream pipe requirements.

At the upstream side, the instrument consists of a gradually decreasing nozzle, through which the medium in a pipe is accelerated. The downstream side has a gradually increasing diffuser section, which enables a high pressure recovery.

As a major part of the output pressure is regained, the Venturi tube is particularly suited for measurement in systems with a low pressure differential. And as a result of the low pressure loss the cost of pumping the medium can be reduced to a minimum.

Pitot Tube

Our FloTec pitot tubes are used for measuring flow using a differential pressure principle. The volumetric flow is calculated from the difference between the static pressure and the dynamic pressure using Bernoulli’s principle and taking into account the pipe inner diameter. Using four dynamic ports this instrument can evaluate a better profile for the velocity inside the pipe. This ensures a higher accuracy in the measurement.

The upstream side generates a break point, and the medium passes around the pitot tube without causing any turbulence. This feature creates a stable pressure with a constant flow co-efficient at the downstream measuring point, even at high flow rates. This principal suits a very wide range of applications in the field of flow measurement.

Venturi Nozzle

The flow nozzle is generally used for measuring the flow of steam as well as non-viscous and high-velocity media. It can be used in a wide variety of applications to measure steam, air, water, vapour, gas & chemical substances. For applications with erosive media a hardened internal surface is available.

The design and manufacture of the flow nozzles complies with the requirements of ISO 5167. Accuracy of ±1.0 % is ensured, with the option of ±0.25 % achievable by means of calibration.

The design of the flow nozzle is based on Bernoulli's equation and consists of a convergent section with a rounded profile and a cylindrical throat. Due to its rigidity the flow nozzle is dimensionally more stable at higher temperature and flow rate than an orifice.

For acceptance tests of power plants, flow nozzles to ASME PTC-6 are also available.

Cone Flow Meter

The FLC-FC cone flow meter is an advanced application of differential pressure technology. Its characterization of the flow profile enables reliable measurement even under the most difficult conditions.

The cone flow meter is ideally suited for applications with limited mounting space and offers a wide and stable turndown, high accuracy and repeatability. It can be produced in accordance with the ISO 5167 reference standard.

The conical primary element has been designed so that its edges are protected from particles in the medium resulting in a very long service life, even in applications with abrasive media.

The optimised flow profile prevents asymmetric flow effects and enables operation with very short upstream and downstream pipes.