⎪ Hydraulic and pneumatic systems ⎪
Left: A BMG Hydraulics HPU and control system is being used to manage the electrodes of a 2.0 MW DC Furnace in Poland. Right: Two cylinders work together to steadily lower the electrodes, which are being consumed in the furnace, while new lengths of electrode are added from the top using a crane.
the mass of the arm and mast, while the elec- trode is consumed in the furnace below. The control of the hydraulic system can be accomplished by a PLC, or managed by an opera- tor in the control room or on the platform above the furnace. The HPU, which was designed by BMG for this prestigious project, conforms to stringent CE certification for operation in Europe. CE certification and conformity were carried out in conjunction with a third-party assessor, in order to precisely meet customer requirements. All relevant information was consolidated into a data pack by the Engineering department. The HPU efficiently combines a number of motors, pumps, accumulators, directional and pressure relief valves, flow control and filtration components. This system demonstrates how common hydraulic components can be applied to smartly achieve fine control and regulated operation of two cylinders in an exceptional application, such as accurately and continu- ously managing electrode consumption in these furnaces. Another recent success for BMG’s hydraulic engineering team was the design and manufac- ture of a radial door hydraulic power unit (HPU) that was urgently required to operate an ore pass radial door at a processing plant in Zambia. This large-scale project required a system that would open and close one cylinder with a stroke of just under 1.5 m using 15 m hoses, ensuring high performance, precision and con- trol. BMG’s solution, which included 56 unique components listed on the general assembly drawing, was an HPU system mounted on a large 630 ℓ tank and supporting frame with two 525 V high-efficiency motor pump sets, three 55 ℓ accumulators and two electrical control panels. The system utilises various push buttons and switches to control key features – including oil level, temperature, pressure, power failure or emergency, as well as directional control. The
smart design of the system makes use of one 55 kW motor pump set to operate the cylinder, while a 4.0 kW motor pump set charges the ac- cumulators and cycles oil through an auxiliary cooler. In the event of an emergency, the operator can press the emergency stop button to switch off all pumps and lock the cylinder in place, or push the emergency stop button that will switch off all pumps and close the gate with the pres- surised fluid stored in the accumulators. The latter action will also automatically take place in the event of a power failure. The completed HPU and cylinder system, which was successfully installed in Zambia at the beginning of 2022, ensures that mined ore is passed efficiently through the materials movement channels by regulating the radial gate control.
before the unit goes to final assembly. All cyl - inders are tested and painted before delivery. BMG enhances its manufacture and repair service with a total design solution, using the latest CAD and CAM software. This service encompasses expertise from manifold design, to manufacturing and assembly of a com- plete system. The company’s 3-D modelling programmes clearly exhibit the interior and exterior of a manifold in a virtual environment, which enables the identification and amend - ment of possible design flaws before fabrication commences. BMG provides a 24-hour customer process support for production efficiency and reliabil - ity centred maintenance throughout southern Africa. This service is enhanced by advanced technical and design support across all func- tional disciplines, along with a comprehensive range of engineering equipment and compo- nents, including bearings, seals and gaskets; power transmission components; hydraulics and pneumatics systems; fluid technology and filtration solutions; drives, motors and controllers; materials handling systems; fasteners and tools. www.bmgworld.net
Manufacturing and repair services
BMG has made substantial in- vestments in manufacturing capabilities in order to efficiently service the hydraulic industry for manifold blocks and cylin- der manufacture. There are dedicated hydraulic cylinder servicing workbenches for the repair, servicing and rebuilding of cylinders, as well as a facility for testing equipment at pres- sures of up to 700 bar, which uses Enerpac equipment.
In accordance with stringent quality and safety specifications, BMG adheres to strict protocols for all cylinder repairs and keeping accurate records of all work done. When a cyl- inder comes into BMG for repair, it is stripped, washed and all components are tagged and hard-stamped for traceability. After compo- nents have been refurbished, they are inspected
A 3D design model of the HPU that BMG’s Engineering team recently designed for use on a newly built furnace in Poland.
July-August 2022 • MechChem Africa ¦ 27
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