How do we do it

The Venturi Effect


The Swiss mathematician and physicist Daniel Bernoulli first published his findings on fluid dynamics in his book Hydrodynamica in 1738.

He was the first to discover the direct relationship between the speed and pressure of a fluid flowing through a pipe. Bernouilli’s principle states that any increase in velocity occurs simultaneously with a decrease in pressure in accordance with Bernouilli’s Equation.

The Venturi Effect

Later in the 18th century, the Italian physicist Giovanni Battista Venturi established that the pressure of a fluid can be reduced by constricting the diameter of the pipe it flows through.

On the basis of Bernoulli’s equation, we can therefore calculate the extent to which this ‘choke’ will increase the velocity of the flow. This phenomenon of simultaneous pressure reduction and velocity increase is commonly used in flow metres, as well as pumps and atomizers.

Technology applying the Bernouilli principle


Our Green Saver steam traps contain a custom-designed nozzle technology that creates a constriction in the pipe to dramatically reduce the pressure of the gas leaving the nozzle outlet. This drop in pressure is sufficient to convert the condensate back into steam in a process known as a ‘flashing’. The ‘flash’ creates a back pressure zone in the nozzle that blocks the flow of steam.

Because condensate is 1,000 times denser than steam, it is able to pass through this back pressure zone, while leaving the steam ‘trapped’ in the system. As more condensate passes through the nozzle, the flashing process is repeated, allowing the back pressure to be maintained.

Our steam traps use technology pioneered in US Navy Nuclear Submarines, where it is crucial that the steam system is compact, efficient and works well under all conditions


This type of steam trap was first used in USS Nautilus, the world’s first nuclear submarine, which first entered service in 1954.

Under the sea, steam traps need to operate reliably in a variety of conditions, including when the submarine is diving at an angle. This ruled out conventional mechanical systems.


Steam ESCO Green Saver steam traps can generally save between 6% and 20% on the total cost of steam, as well as reducing emissions. Because there are no moving parts, they are reliable, compact, and easy to install. As a result of these secondary benefits, they also offer huge savings over conventional, mechanical steam traps when it comes to maintenance – Green Saver steam traps can operate for 20 years or more without requiring replacement.ns