A simple physical principle makes it possible for Venturi orifice steam traps to operate without moving parts. Who discovered it and why has there still been scope for further optimising this proven technology in recent years?
Although Venturi orifice steam traps only came onto the market in the 1990s, the principle on which they are based has been known for a long time. At the end of the 18th century, the Italian physicist and scientist Giovanni Battista Venturi discovered the phenomenon that would later bear his name. The Venturi effect occurs when a fluid flows through a pipe that gets narrower in certain sections. When this happens, the flow velocity of the fluid increases, but the pressure drops. With this discovery, Venturi laid the foundation for numerous developments in the field of fluid mechanics. Understanding the Venturi effect has since helped engineers to develop systems that efficiently control the flow of fluids in various applications – from industrial processes to medical devices. 200 years after its discovery, the principle also laid the foundation for the development of Venturi orifice steam traps.
The magic of Venturi orifice steam traps
In 1995, the first Venturi orifice steam trap was patented in Bristol, UK. This invention marked an important milestone, as it offered an efficient alternative to vulnerable mechanical steam traps.
Nigel Egginton, Managing Director of EBE Engineering, who worked for the company as Marketing Director, and was involved in a marketing and sales capacity, was immediately hooked on the technology. “In engineering, less is more. That’s why I’m still fascinated by the simplicity of the design,” says Nigel Egginton and adds: “A technology that works without any moving parts and simply utilises the physical properties of steam and condensate to replace a mechanical device is simply impressive.”
Venturi orifice steam traps utilise the different densities of steam and condensate. Since steam has a lower density than water, it cannot flow through an orifice full of condensate. This allows condensate to be efficiently separated and drained from a heating system without allowing steam to escape. In addition to the density differences, the thermodynamic properties of energy conservation also come into play in the Venturi section of the steam trap. All condensate has residual energy or enthalpy. This residual energy causes a small percentage of the condensate to turn back into steam, known as ‘flash’ steam. The resulting expansion of the condensate creates a back pressure which reduces the velocity that the condensate flows through the orifice. Effectively creating a ‘fluid’ seal between the steam side and the condensate side of the steam trap.
Market-orientated further development
Since it was patented, Venturi orifice steam trap technology has undergone significant advances and adaptations. Several companies have contributed to their development, but EBE Engineering is characterised by a particularly innovative approach. “After my former employer was taken over by a Canadian company, I was made redundant. But I was still convinced that the Venturi orifice technology was unbeatable, so I decided to set up my own company,” recalls Nigel Egginton. “The existing products were not designed to meet the needs of industrial end users. This motivated me to develop a new design that would meet the requirements of the market.”
This gave rise to the ECOFLOW Venturi steam trap, which was launched on the market for the first time in 2017. It is the first Venturi orifice steam trap in the world to be completely cast in a single housing. The advantage of this design is twofold, with a completely cast housing, including flanges, there are no weld joints and because the Venturi sectors are embedded directly in the housing it allows a broader spectrum of flow rates to be handled. The cornerstone of the design however is the modular concept of the venturi orifice inserts. EBE Engineering is the only manufacturer capable of offering a range of removable inserts that cover steam flow rates from a few kilogrammes up to several tonnes in the same housing. Together with the standardised connection sizes, customers therefore benefit from much greater flexibility. With further design features, EBE Engineering has also succeeded in guaranteeing the reliability of the ECOFLOW steam trap over a long service life. Firstly, the upper cavity or chamber of the ECOFLOW steam trap is equipped with fully encapsulated graphite seals, which ensure outstanding durability and reliability. Secondly, the design using four set screws applies linear pressure and thus eliminates torsional force on the seal. This increases the longevity and performance of the steam trap.
Thanks to these adaptations, there are no more defective traps in steam systems with ECOFLOW Venturi orifice steam traps and downtimes are reduced to a minimum. The traps also improve the efficiency and reliability of the heat transfer system and significantly reduce steam costs.
Advances in Venturi orifice technology, particularly in design and functionality, have significantly improved the efficiency and reliability of steam systems. The integration of other features such as fully encapsulated seals and the ability to handle various flow rates make modern Venturi orifice steam traps the preferred solution for industrial steam system users.
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