CONTROL VALVES FIND A SWEET SPOT PUMPS, VALVES & ACTUATORS
The reliability of components in the customer’s process control environment is key to avoiding unplanned downtime for repairs (Image Source:
shutterstock_693307864)
Reliability issues associated with the existing valves at a sugar refinery in East London has led to the specification of control valves from Bürkert. The replacement valves were easy to install and have improved machine uptime
T
he reliability of components in a process control environment is key to avoiding unplanned downtime for repairs. For a
sugar refinery in East London, repeated replacement of a control valve and a poor mean time between failures (MTBF) led the company to seek an alternative that could cope in a challenging washwater application. Bürkert’s ELEMENT range of process control valves was able to deliver the solution. The Refinery is the largest sugar refinery in
Europe with a capacity of 1.2 million tonnes per year. Towards the end of the process to remove sugar from the cane, a mixture of sugar crystals and molasses, known as massecuite, is delivered to a number of
centrifuges, which spin at speeds up to 1,200 rpm. This process separates the sugar crystals, which are then
washed and dried, producing granulated sugar. The centrifuges can process
over 20 loads per hour with each batch needing to be washed before it is dried and transferred to the storage silos. The washwater used during this process is controlled by a ball valve with a spring return actuator and an electrical position indicator. Each control valve is
required to perform hundreds of thousands of operations per year
and is working with water at 90°C as well as a pressure of 6 bar. This arduous environment applies to all centrifuges that are in operation at the Refinery. However, after several years in operation, the existing valves had a poor reliability record and were the cause of leaks, which resulted in increased maintenance costs. As a result, research was carried out to find an alternative design of valve that could
handle the repetitive operation as well as the working environment and provide more reliable service. This led to the specification of the Bürkert Type 2100 angle seat valves and the Type 8697 pneumatic control unit, both of which are designed for hygienic applications. This selection of control valve is well-
matched for decentralised process automation and offers excellent sealing properties as well as valve status feedback via LEDs on the pneumatic control unit itself. Together with the use of chemically-resistant materials in its construction and proven IP ratings, the Bürkert control valve assembly is suited to applications in the food and beverage sector. Using planned downtime in
production, the plant initially installed 16 Bürkert control valves, with a further 16 larger control valves being installed on a similar application. The senior reliability engineer at the
plant commented: “These new valves have proven to be easy
Bürkert’s Type 2100 angle seat valve and Type 8697 pneumatic control unit
to install and a great improvement in terms of reliability. Their introduction has contributed to an
improvement in machine up time at our facility and their high cycling ability makes them well-suited to wide range of applications in the plant.”
Bürkert Fluid Control Systems
www.burkert.co.uk
MAY 2021 | PROCESS & CONTROL 41
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