|Weighing over 72 tonnes (80 tons US) the SLK4390WXFS double deck flat vibrating screen can process around 9,000 t/hr (10,000 t/hr US) of slurry in a metal extraction process. This Schenck Process vibrating screen is driven by four eccentric gearbox DF704 exciters and could well be the largest screen ever designed and manufactured.
The model is approximately 5.5 m (18’) wide, 10.5 m (35’) long and 6.5 m (21’) high and is driven by the four DF704 exciters, mounted in pairs on two exciter beams, with a dual drive arrangement of twin 90 kW (120 HP) motors and variable speed controllers. The screen uses continuous vibration to process 3500 Metric t/h (approx. 3800 t/h US) of dense slurry or 9,000 Metric t/h (approx. 10,000 t/h US) of dilute slurry into three sizes.
With an installed mass of 120 tonnes (135 tons US), a vibrated mass of 72 tonnes (80 tons US) and exciters producing over 4.5g acceleration that generate a combined force equivalent to fourteen Boeing 747 jet engines at full thrust, there is no surprise the screen has been nicknamed “The Beast”.
A machine of this size has the potential to impair the rest of the plant due to the vibrations transmitted into the support structure. This risk has been addressed by the use of a tuned vibration absorber called an Isolation Frame so that in operation, less than 0.4% of the exciter force will be transmitted into the building structure.
The entire assembly, including the vibration isolation frame, transport trolley (which carries the motors, built-in water spray system, and fines chute), is equipped with a jacking system and wheels to allow rollout to expedite screen change out when maintenance is due. Only the electrical supply cables and water supply piping requires disconnection before the trolley assembly is moved. Whilst the screen weighs 72 tonnes (80 tons US), the entire assembly results in an installed mass of 120 tonnes (135 tons US). The trolley allows the combined screen, isolation frame, and ancillary equipment to be lifted using an overhead crane as a single 120 tonnes (135 tons US) assembly.
Typical Project Application
This is the era of large open-pit copper and gold mines in many districts and countries. It is typical that these mines use “40 foot” Semi-Autogenous Mills (SAG mills) to process the ore, often in more than one production line. Many of these projects will process on multiple parallel lines and use two, three or four screens in producing many thousands of tonnes of copper, gold, molybdenum and other metals to satisfy the world’s demand for manufactured products.
Teyhan said that “Schenck Process application knowledge was vital to get this right; understanding how the infeed material behaves as a mixture of rocks, clays and water and manipulate this to achieve the goal of separating the fractions into different streams comes from the combined years of experience of the Schenck Process application and engineering team”.
The screen is equipped with a multi-channel ‘CONiQ® Monitor’ condition monitoring system that is “cross connected” to all four exciters, Its purpose is to detect and evaluate phase defects, check and record the bearing and gear vibrations, operating oil temperature and gross machine motion in six (6) degrees of freedom (three translational and three rotational).
Schenck Process, our clients and their engineering teams, are all engaged and focused on producing an optimum screen installation. Schenck Process has a global footprint in the design, engineering, manufacture and testing of vibrating equipment for the mining, mineral processing and aggregate industries.