Venturi Tubes

A venturi creates a constriction within a pipe (classically an hourglass shape) that varies the flow characteristics of a fluid (either liquid or gas) travelling through the tube. As the fluid velocity in the throat is increased there is a consequential drop in pressure. Italian scientist Giovanni B Venturi (1746-1822) was the first to observe this phenomenon.

The fact that a pressure drop accompanies an increased flow velocity is fundamental to the laws of fluid dynamics. Swiss mathematician, Daniel Bernoulli, derived the interrelationship between pressure, velocity and other physical properties of fluid in 1738. Classically, his theorem is used in the design of aircraft wings to create lift from the flow of air over the wing profile.

There are basically two applications for a venturi. By attaching manometers to three sections of the tube, the pressure drop can be measured and the flow rate through the throat calculated. This is termed a Venturi Meter.

More commonly, a venturi can use this negative pressure to draw a second fluid into the primary flow. This effect has found many applications across a range of industries. However, the basic mechanism has remained the same for almost 200 years.

York Oil and Gas is manufacturer of all types of Venturi Tubes which are designed in accordance with our clients requirements or any international standard. Most common used standard is ISO 5167 and this standard covers three types of classical venturi tubes: A: Venturi tube with ‘as cast’ convergent section B: Venturi tube with machined convergent section C: Venturi tube with a rough-welded sheet-iron convergent section Type B venturies can be machined by us over the inlet and outlet sections in the whole range of ISO 5167. Type C venturies are nomally made out of machined throat section and sheet steel inlet and outlet cone-sections. The throat section can be honed to achieve a smoother surface roughness. Type C venturies are reinforced with stiffeners and supplied with lifting lugs.