VENTURI NOZZLE

Venturi Nozzles are used as flow elements for flow measurement of aggressive and non-aggressive gases and liquids. Venturi Nozzles can be assembled as directly welded, flange ends or wafer type (between flanges).

DESIGN

Venturi nozzles consist of a rounded inlet section, a cylindrical throat and an outlet cone. The upstream pressure tapping is typically manufactured as a single bore. The throat pressure tapping usually consists of four bore holes which lead to a ring chamber or annular ring. For some applications it is recommended to design the throat tapping as a single bore.

General shape of Venturi Nozzle:

Nozzle - Venturi Nozzle

Venturi nozzles are made from a wear-resistant material like stainless steel.

PRESSURE TAPS

The tapping interface is provided within the primary flow element. Typical tap interface designs are:

  • Plain ends for fittings
  • Butt weld ends
  • Threaded ends
  • Flanged ends
  • Compression fitting ends

ADVANTAGES

Compared to orifice plates, nozzles are recommended for applications which require low pressure losses. At similar flow values, nozzles generate less differential pressure which results in lower permanent pressure loss. The rounded inlet profile is less susceptible to erosion in comparison to the sharp edge of an orifice plate. Hence, nozzles achieve higher service life times.

MEASURING UNCERTAINTY

 Uncertainty of Venturi Nozzles is between 1,2% – 1,8%, depending on the application. The uncertainty depends on Beta Ratio and Reynolds Number.

PRESSURE LOSS

The pressure loss depends on the diameter ratio β (d/D) and amounts to approx. 5 – 20% of the differential pressure.

NOMINAL DIAMETER (according to ISO 5167)

DN 65 to DN 500 / 2 1/2“ to 20“ according to ISO 5167 (if requested other sizes are possible)

PRESSURE RATING

up to PN 400 (EN) / 2500# (ASME)

SEALING SURFACE OF NOZZLE

Sealing surface are designed according to EN 1092-1:

  • flat (form B1 and B2)
  • groove (form D)
  • tongue (form C)
  • female (form E)
  • male (form E)

Surfaces according to ASME B16.5:

  • flat (RF and SF)
  • groove (small/large)
  • tongue (small/large)
  • male/female (small/large)
  • RTJ male or female

Surfaces can also be designed according to other flange standards specified by the customer.

Also, venturi nozzles can be designed as flange ends according to EN 1092-1 / ASME B16.5 / JIS- BS- or DIN-Standards / or other specified standards

THROAT DIAMETER "d"

The calculation of the bore diameter is based on the supplied process data. All relevant standards and regulations will be considered. The calculation is part of the scope of supply.

MARKING

Flow nozzle body is marked by lazer marking. The marking consists:

  • Tag no. of flow element
  • Pressure rating
  • Size or Dimensions
  • Throat Diameter
  • Material
  • Direction of flow (Upstream and Downstream marking)

MATERIAL

The material of venturi nozzle is chosen based on process medium, pressure and temperature. 304 and 316 are the most commonly used stainless steel materials for flow nozzles.

Non-metal material is used for aggressive processes. PTFE, PVDF etc.

INSTALLATION

Mounted between flanges according to EN 1092-1 / ASME B 16.5 or other standards such as DIN, JIS or BS. The pipe may be positioned horizontally, vertically or sloped.

QUALITY CONTROL

Our design and manufacturing are qualified according to ISO 9001. Manufacture and test works are done in accordance with relevant codes and standards. These are PED, EN 14380, ASME Section XIII etc.

Each product is inspected and certified with EN 10204 3.1 certificate. If requested, 3.2 certification is available.