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PUMPS, VALVES & ACTUATORS MEETING STANDARDS IN SUSTAINABILITY


Kieran Bennet, Industry Manager Food & Beverage, Chemical & Petrochemical at Bürkert, explains the sustainability benefits of hydroformed valve bodies


F


or fluid control applications in sectors such as pharmaceuticals as well as food & beverage production, manufacturers


can increase productivity and reduce costs while helping to meet their sustainability objectives by integrating improved control valves. Hydroformed valve bodies for diaphragm valves achieve high strength and light weight. This makes hydroformed valve bodies far more energy efficient compared to forged or cast designs, and the manufacturing process is inherently more sustainable too. In many process manufacturing


applications, diaphragm valves support the hygiene imperative. In addition to preventing contamination, diaphragm valve design enables cleaning and sterilisation to meet regulatory standards. While clean in place (CIP) and sterilisation in place (SIP) practices are essential, they demand time and energy. A hygienic system, comprising tubing and


valves, is steam sterilised to over 100°C and is then air cooled to below 45°C where production can resume. The longer each process takes, the lower the system’s production capacity. Increased time also means higher energy use, both with a greater demand on steam generation to reach the required sterilisation level, as well as powering the air cooling system to reduce the temperature. Critical to this process is the choice of


valve body. Though they comprise just a fraction of the system’s total length of tube, even when hundreds might be used, production cannot resume until the valve bodies are cleaned, sterilised, and cooled. This makes the importance of valve body specification much greater than their physical scale might suggest. Traditionally, diaphragm valve bodies are


forged, where the stainless steel, required for its hygienic properties, is heated and compressed into place. A forged valve body has a longer heat transfer capacity, so a cast design, where the stainless steel is shaped in a mould, is preferable. Faster still, both at heating


up and cooling down, is a valve body manufactured with hydroforming, which involves high pressure fluid to create the design. This can be combined with the processes of annealing that increases durability by relieving residual stress and improving corrosion resistance, as well as laser welding that can establish a hygienic seal without adding any extra material. Together, these manufacturing techniques


create a more lightweight valve body design, and this low mass achieves rapid heat transfer. While a forged valve body can take nearly 10 minutes to cool down to 45°C from the sterilisation temperature, a comparative hydroformed valve body reaches the mark


The Bürkert Tube Valve Body


generates 58%


less emissions in carbon dioxide


equivalent during its manufacture, compared to a


forged body of the same size


is also far greener. For a 1.5” device, Trusted Footprint confirms that the Bürkert Tube Valve Body generates 58% less emissions in carbon dioxide equivalent during its manufacture, which includes steel production as well as processing techniques, compared to a forged body of the same size. Although cost saving and sustainability


improvements are highly important, valve body performance is fundamental. To ensure optimum durability, the design and manufacturing techniques of the valve body have to meet burst and leak pressure specifications. A safety factor multiple times the required real-world level can be achieved through the hydroforming and annealing processes, combined with the necessary conformance in wall thickness. It’s also essential to ensure that any welding can withstand the sudden temperature changes of


sterilisation and cooling, as well as in just


over four minutes, and this difference


can significantly speed up production turnaround. A hydroformed design also reduces the steam requirement, and hence


energy use, necessary during SIP. This can represent a significant cost saving, especially when multiplied across all installed valves. As hydroformed valve bodies can be as much as 75% lighter, this also saves costs in installation with fewer supporting structures required. This energy saving also provides an


advantage in sustainability. According to the independent verifier, Trusted Footprint, comparing 1” tubing, up to 38% less gCO2 equivalent can be saved by using a hydroformed design, like the Bürkert Tube Valve Body, rather than a forged variant. Taking carbon emissions in valve body manufacture into consideration, hydroforming


resistance to cracking under vibration. Equally crucial is hygienic conformance.


316L stainless steel achieves this, and the design, including weld lines, has to remain corrosion-free under intensive saline testing. Ultimately, a material inspection certificate 3.1 according to EN10204, with a CIP-capable design that meets EHEDG Type EL, CLASS I Certification, as well as 3-A Sanitary Standards, create trust in hygienic conformance. While reliability and hygienic


conformance should be a given in specification, optimising valve body design can not only increase productivity but can also enhance the sustainability credentials processors need from a supplier. Integrating light, strong tube valve bodies, these producers can reduce costs in production as well.


Bürkert Fluid Control Systems www.burkert.co.uk


OCTOBER 2023 | PROCESS & CONTROL 17


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