Issue link: https://geospatial.trimble.com/en/resources/i/1415432
76 Spring 2019 breakdowns, necessitating high standards of robustness and reliability from valves and actuators. Tank farms typically rely on gate valves to route hydrocarbons into and out of the tanks, plus ball and butterfl y valves for piggable pipelines and emergency shutdown (ESD) applications. Gate valves require multi-turn actuators (Figure 2), while part-turn actuators (or multi-turn actuators with part-turn gearboxes) are used for ball and butterfl y valves. Valve sizes range from 4 to 32 in. (DN100 – DN800), with operating pressures up to 600 psi (40 bar). The chosen actuators must be able to deliver the necessary torques consistently and reliably, even for the largest valves. Large electric actuators can deliver torques of up to 500 000 ft-lb (675 000 Nm). Actuators used for fl ammable liquids storage are certifi ed for use in potentially explosive atmospheres. Depending on the site location, regionally applicable standards include IECEx, FM (US), ATEX (Europe), EAC (Russian Federation), or NEPSI (China). Sourcing, installation and maintenance Ease of installation and commissioning is important. Ideally, a small number of actuator models in different sizes and confi gurations will cover all the valves on the site. AUMA has adopted a modular design approach, thus reducing the number of different actuator types and spare parts required and bringing advantages in terms of inventory. Consistency in the user interfaces also facilitates operator training. A modular actuator concept meets varied demands with a set of standard components. A broad range of multi-turn and part-turn actuators is available for different torque ranges, power sources and valve attachments. Modular design, including the ability to mount the actuator controls at some distance from the motor and gearbox, also makes it easier to install actuators in locations that are diffi cult to access. Modularity includes features like plug-and-play electrical connections, which simplify cabling, commissioning, maintenance and repair. A non-intrusive setup, which allows actuators to be confi gured without opening their housings, is another feature that is valuable during commissioning, maintenance and repair. Usually, the valve's open and closed end positions need to be calibrated, and limit switches for valve travel and/or maximum torque need to be set. With non-intrusive setup, this can be done quickly and easily using integral local controls with intuitive user interface. Case study 1: NWO Wilhelmshaven tank farm NWO Wilhelmshaven, Germany's largest crude oil terminal, started deploying AUMA actuators more than 25 years ago. Now, about 250 actuators provide reliable 24/7 service (Figure 3). Robust mechanics, a modular actuator design and a wide variety of actuator sizes have allowed the plant operator to fulfi l the needs of all of its valve control applications from a single supplier. Advanced valve control Tank farms typically rely on large numbers of valves in manifolds to create many different fl uid transfer routes Figure 1. Electric actuators provide precise and reliable valve control on tank farms. Figure 3. Approximately 250 AUMA electric valve actuators provide reliable service at NWO Wilhelmshaven, Germany's largest crude oil terminal. Figure 2. Gate valves are one of the most common valve types used to control the flow of hydrocarbons in tank farms.