Permutit Power Products Flow-Limiting Cavitating Venturi and Multi-Orifice Elements

Permutit® products offers flow limiting (cavitation) venturis and multi-orifice flow elements for limiting flows in critical lines where a sudden decrease in downstream pressure (due to rupture etc) can occur. These are designed for choke flow conditions at a maximum predefined flow rate.

Due to the unique inlet curve profile and a recovery cone, erosion under these conditions is limited to such an extent on the critical surfaces that the flow characteristics, and mechanical integrity is not affected. These units can be tested at actual site conditions where required to authenticate the design. Siemens Water Technologies has compiled a history of such designs enabling us to test these at lower pressures in the testing lab, and accurately predict limiting flows from the test data. Low pressure test is less expensive. These devices are also used as flow control devices at lower normal operating flow rates.

Siemens also offers multi-orifice designs that will perform the same function as cavitating venturis. The predictability of the limiting flow, pressure drop is not as accurate as a cavitating venturi, but it can be used where there is flexibility in the design requirements. These assemblies are designed with a number of orifices in series such that cavitation does not occur at any stage. The number of the orifices needed is calculated for each design requirement. In the multi orifice design a removable orifice can be added so that the performance can be fine tuned at site or lab, for same accuracy as an cavitating venturi.

Construction

The venturis and the multi-orifices are generally provided in various grades of stainless steel, but other materials can be provided as required. These can be welded in line or provided with flanged connections. The removable orifice is provided with flanged ends.

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Design Features

Cavitating venturis offered in sizes 2" through 6" for weld-in or flange mounting
Cavitating venturis are available with throat tap sets
Recovery cones designed for individual pressure recovery conditions
Flanged removable orifice included in the multiorifice design

Advantages

Cavitating Venturi Designs

Uncalibrated accuracy to +/- 5% of pressure or flow rate

Actual characteristics can be determined by full pressure test in lab

Less susceptible to wear and erosion

Erosion does not affect design or performance

No moving parts to wear or breakdown such as in pressure reducing valves, etc.

Shorter lengths, can be fit into existing pipelines

Meets wide variety of flow and application requirements due to custom design

Multiorifice Designs

Low cost

Removable orifice available to fine tune design

Highest quality design and manufacturing available for both designs to meet requirements of ASME, 10CFR50, Appendix B, ANSI B31.1, seismic and natural frequency requirements

Quality Control

We have been the trusted source for all grades of nuclear and commercial demineralizers for many years. Our capabilities include dissimilar metal welding and fabrication to ANSI and RDT specifications. We meet the requirements of the ASME Codes and 10CFR50, Appendix B through our stringent quality assurance program.

The Siemens Advantage

As the leader in the water treatment industry, Siemens Water Technologies has the greatest depth of personnel and technological resources to overcome any challenge. We offer the widest variety of specialty products for the power generating industry, including many custom components. Please contact us for additional information about your specific requirements.

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Raj Sang

908.704.9027 ext 104

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Product Documentation

Product Data Sheet
Cavitating Venturi (pdf)
Pressure Breakdown Multi-Orifice Flanged Design (pdf)
Pressure Breakdown Multi-Orifice Weld-In Design (pdf)

More Information

For technical or sales information, call 908.704.9027 ex 104 or send an email to Raj Sang:
rajendra.sang@siemens.com