Proflow Venturi offers a unique and modern approach to commissioning modern heating and chilled water systems. The concepts incorporated into this valve provide significant benefits to consultants, contractors and commissioning engineers, enabling systems to be designed, installed and handed over without complications. Choosing the Proflow Venturi offers many advantages over the more commonly used fixed orifice plate. The venturi orifice delivers much greater measuring accuracy of +/-3% across the entire range of valves and using the venturi principle negates the need for 3-5 times the pipe diameter of straight pipe to gain an accurate reading. The trumpet shaped design of the venturi nozzle will return a higher, cleaner signal (typically 10-30 kpa dependent on flow rate). This is achieved without the pressure loss associated with more conventional orifice plates, which makes commissioning easier and simpler than ever before. At the heart of all Proflow Venturi valves is the integrated fixed orifice venturi. The venturi principle was first demonstrated in 1797; but in simple terms, water is accelerated through the venturi orifice, which increases the velocity of the flow and the pressure differential, proportionally amplifying the signal generated. Significant pressure drop is recovered after the water has passed through the venturi nozzle. The Proflow Venturi uses a quarter turn ball valve for isolation and a needle valve for regulation in the same body. This unique design feature enables the valve to be used for isolation purposes without altering the setting on the regulation needle. This all makes Proflow Venturi easy to regulate, isolate, install and operate. In the traditional method of commissioning, all commissioning stations usually require a certain length of straight pipeline, excluding fittings, upstream from the valve to ensure correct flow measurement. This length varies between five and ten pipe diameters, depending on the manufacturers recommended guidelines. So if the valve size is 50mm, for example, the length required will be between 250mm and 500mm. The dimension is of course increased if the valve is fitted immediately after the pump. Some commissioning stations also require a downstream straight length. With Proflow Venturi technology, (except for immediately after a pump) no straight lengths are required either up or down stream and this can be a serious advantage in a tight plant room and is a more elegant and modern method of commissioning. The Proflow Venturi has also been designed for installation in any orientation, even with the test points facing down. This feature is possible due to the creation of a cylindrical chamber around the outside of the venturi cartridge and another chamber in the housing. Two pilot holes from the high and low pressure sides of the venturi feed the pressure differential into the chambers, on the outside of which are located the test points. The pilot holes from the venturi to the chamber are positioned at 3 and 9 o’ clock positions when the valve is positioned upright. Therefore, should either pilot hole fill with debris (when positioned pointing down) the other will be pointing up, allowing the signal to be measured. “The Proflow Venturi is suitable for connecting to most steel, copper or plastic pipe systems and from a technical viewpoint has been optimised to accurately deliver design flow rates and signal and setting data to ensure trouble free installation and operation, “ said Pegler Yorkshire Product manager Barrie Plant, “This valve delivers high accuracy and performance and has no rival as a modern commissioning tool.” | 
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