Throttling Device

A throttling device is also called a throttling flowmeter. A typical differential pressure flow meter. Commonly used to measure the flow of gas, liquid and steam in industrial production.

Throttling Device

Throttling device is a flow device in which the fluid filled with the pipe flows through the pipe. The stream will form a local contraction at the throttling. This will increase the flow velocity and reduce the static pressure. So a differential pressure is generated before and after the throttling ( Or called throttling flowmeter).

Sino-Inst, Manufacturer for differential pressure flow meters. Including the Orifice plate, Venturi, Annubar, etc. Suitable for liquid, gas, and steam flow measurement. Please contact our sales engineers for technical support!

Features of Throttling Device

  • The throttling device has the advantages of simple structure, firmness, reliable work, stable performance, high degree, and low price. Therefore, the amount of throttling device has an advantage compared with other flow meters.
  • Wide range of pipe diameter, φ2~φ3000mm (or larger). The cross-sectional shape, round or rectangular shape is acceptable.
  • The standard throttling device can determine its measurement degree without real flow calibration.
  • Applicable to a wide range of tested media. It can be used for almost all gas, steam and liquid flow measurement.
  • The working pressure can be as high as 32Mpa. Can also be used for negative pressure.
  • Medium temperature range: -l85~+650℃. Other flowmeters are not yet possible.
  • The structure of non-standard throttling device is diverse. Almost applicable to various fluid flow measurement.
  • The flow range can be changed on site by setting the range of the differential pressure transmitter.
  • It is simple to use, operate, easy to master, and daily maintenance is small.

Extended reading: V-Cone Flow Meter Working Principle

Throttling Device type and composition

The throttling device consists of throttling parts (such as orifice plate, nozzle, etc.). Pressure Sensors, fastening devices (flanges, bolts, nuts, gaskets, etc.), and other accessories (pressure guiding tubes, stop Valve, etc.). It can also be equipped with front and rear measuring tubes and flanges at both ends of the straight pipe section.

Throttle Parts

Code NameCodeNameCodeName
ARestrictor orificeKWide Edge OrificeTMachined Venturi
BStandard orifice or eight-slot orificeLVenturi nozzleUWedge flowmeter
CLong diameter nozzleMSmall nozzleVV cone flowmeter
DEnd orifice plateNOrifice plateWRough welded iron plate venturi
E1/4 arc orifice (nozzle)OEccentric orificeXRough cast venturi
FLow pressure loss flowmeterPISA1932 nozzle or eight-slot nozzleYDouble orifice plate
GHigh pressure lens aperture plateQRound hole plateZAveraging tube flowmeter
HAnnular orificeRConical inlet orifice
JWing type wind measuring deviceSDouble venturi

Extended Reading: Differential Pressure (DP) Flow Meters Technology

Pressure method

HCorner connection pressure (ring chamber)JDiameter pressure
ZCorner connection pressure (drilling)TSpecial pressure
FFlange pressure

Note: The current limiting orifice has no such representation method


Diameter (mm)253240506580100125150175200225250
Diameter (mm)2753003253503754004505006007008009001000

Pipe diameter greater than 1000 is expressed as 1/10 of the actual pipe diameter

Nominal pressure

Nominal pressure(Mpa)0.611.62.546.4101620253242

The special nominal pressure is filled in according to the actual design pressure value

Supply method

CodeSupply content
AComplete device with front 10D and rear 5D measuring tubes (including connecting flange and process flange)
A1Complete device with front 10D and rear 5D measuring tube (including connecting flange)
A2Complete device with front 10D and rear 5D measuring tube (pipe end inverted bevel)
BA complete set of equipment with upstream and downstream measuring tubes (including process flanges) according to petrochemical standards (HGJ516-87)
B1According to the petrochemical standard (HGJ516-87), a complete set of equipment with upstream and downstream measuring pipes (pipe end inverted bevel)
B2According to the petrochemical standard (HGJ516-87), a complete set of equipment without upstream and downstream measuring tubes
CAccording to the standard of the Ministry of Electric Power (GD87-1101) a complete set of equipment with upstream and downstream measuring tubes
DFlanges, ring chambers or pressure-taking flanges, throttles, pressure pipes, fasteners and other complete sets of devices without measuring tubes
ESingle throttle

Extended reading: [Working principle&Price]SI3051ANB Annubar Flow Meter

The principle of Throttling Device flow measurement

The throttling device artificially causes throttling in the pipeline through which the medium circulates (as shown in the figure). When the measured medium flows through the throttling device, it causes a local contraction. The stream is concentrated, the flow velocity increases, and the static pressure decreases.

Therefore, differential pressure is generated between the upstream and downstream sides of the throttle. There is a certain functional relationship between this differential pressure and the flow rate. The greater the flow, the greater the differential pressure generated. Therefore, the flow can be measured by measuring the differential pressure.

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Throttling Device Types

As the most important branch of the flow meter, the throttling device is divided into two categories: standard throttling devices and non-standard throttling devices.

Standard throttling devices include: standard orifice plate, ISA standard nozzle, long neck nozzle, classic venturi tube and venturi nozzle;

Non-standard throttling devices include: annular orifice plate. Quarter circle nozzle. Quarter circle orifice plate. Conical inlet orifice plate. Round missing orifice plate. Eccentric orifice plate. Double orifice plate. Low pressure loss flow tube. Rectangular venturi tube, V-cone flowmeter, wedge flowmeter, built-in orifice, restrictive orifice, etc.

Extended reading​: What is a flow nozzle?

Orifice Throttle Flow Meter

Orifice plate flow meter works together with an orifice plate, differential pressure transmitter, with Differential Pressure Measurement principle. Easy installation. Orifice plate flow meters can be used with gases, liquids, corrosive, and high temperature fluids. Orifice flow meters can measure steam, gas, liquids, and many industrial areas. Applications include steam flow, boiler feedwater, and fluid flow rates in building water lines.

Extended reading: Integral DP Flow Meter|Gas, liquid, steam|Compact structure

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Sino-Inst offers Throttling Devices. A wide variety of Throttling Device options are available to you, such as brass, carbon steel. You can also choose from free samples.

Sino-Inst is an Throttling Device supplier. Orifice plate flow meter products are most popular in Domestic Market, Southeast Asia, and Mid East.

You can ensure product safety by selecting from certified suppliers, including 375 with ISO9001, ISO14001, and Other certification.

This entry was posted in DP Flow Meters, Flow Meters by KimGuo11. Bookmark the permalink.

About KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects. Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.