General Kinematics Two-Mass Screen Applications
The General Kinematics Two-Mass Screen technology is gaining global momentum in the Mining Industry. They have been and currently are the leader in Vibrating technology for over fifty years in the Foundry and other industries. Two-Mass screens are high throughput screens that can handle up to a 30% - 40% throughput increase with the same or better efficiency (in the same footprint as an existing brute force banana screen) and on an equal comparison basis. The GK screen can use much less energy to do this bigger task, they are inherently more reliable, and they offer a longer service life for a lower cost of ownership. Additionally, the preferred OEM states the inclusion of their short integral cascading grizzly feed deck will produce even higher performance and efficiency gains. The preferred OEM of this technology has produced Two-Mass screens for decades. In 2005, this OEM redesigned their Two-Mass screens into a modular configuration in response to demand for higher throughput screens. There are over one hundred of these new style large screens currently in service.
One of the many successful installations of a General Kinematics Two-Mass screen is presented below:
Two-Mass STM-SCREEN™ 10x20 single deck screen
In comparison both the original screen and the new STM-SCREEN™ 10x20 are the same size and with the same installed angle and receive the same feed rates from the AG mills.
The following is comparing the operating parameters of the screens:
Application and Definition of Two-Mass Screen Technology
Standard Brute drive force is compared to Two-Mass drive below:
The standard single mass screen as depicted by Figure 1 is generally recognized in the mining industry. It is characterized by the screen body – labeled as the single mass (Mt) that is supported by isolation springs (Kiso). The stroke needed to process material is obtained by incorporating large eccentric wheels and/or drive boxes (Fb) directly mounted to the screen body via a drive tube.
Less well known in the industry is the Two-Mass or sub-resonant screen as depicted by Figure 2. The body (Mt) and isolations springs (Kiso) are similar to its single mass counterpart. This design then incorporates a secondary mass (Me) and reactor spring system (Kr) strategically designed to resonate at speeds near the running speed of the machine. Because of this resonance, the same stroke and process capacity is accomplished with smaller wheels and drive systems (F2). Many of the benefits of this design center around the lower driving forces and close proximity of the natural frequency to the running speed.
Two-Mass vibratory technology goes beyond the boundaries of conventional vibratory equipment. This allows for increased machine size, process capabilities, efficiencies, reliability and uptime. Material responsive – equipment does not dampen under product surges and actually increases stroke to compensate. Machines are designed and built to have a longer service life.
· Too many springs
· Unique exciter/drive mechanism
· Weight = Cost
Two-Mass Screen Summary
Two-Mass Screen technology has been demonstrated to offer an increase of at least 30% in throughput compared to the equivalent footprint brute force screen at the same or better efficiency. This type of screen does so while offering greatly reduced screen deck wear, greatly reduced power consumption, quieter operation, and transmits negligible vibration and dynamic load into the plant structure. Potential also exists to significantly reduce magnetite consumption when used in drain and rinse applications - even at elevated throughput rates.
GK has had thirty-one Two-Mass Screens installed in Australia over the last five years in various industries and styles. Around the world, General Kinematics has over 150 of the same style of large Two-Mass Screens and hundreds more including all Two-Mass Screen types.
The supplier side team has demonstrated a mature competence introducing new technology to the unique realities of mining applications, with this step-change productivity improving technology proven ready for scaled uptake. Leading to the open question: “How can we best leverage this new tech opportunity for our business and do so efficiently?”.
A detailed white paper on the subject will be presented by Ed Wipf, President, EdRockMan IV LLC at the CIM – 2019 convention in Montreal – April 28 – May 1, 2019.