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When chemically bonded came of age

It is 40 years since Omega Sinto Foundry Machinery Ltd (known then as Baker Perkins) developed and launched the world’s first single trough, high speed continuous mixer for the no-bake process (fig.1). Called the Omega 1-series, this mixer radically changed the way that the chemically bonded sand process could be used and set the precedent for all subsequent continuous mixer designs.

Before the arrival of the Omega 1-series, the only mixer design available was either the batch mixer or the mixer with twin mixing troughs and a small vertical mixing chamber at the discharge end (one mixing trough for the acid and the other trough for the resin). There were two options available for the twin-trough design of mixer, the well know Fordath ‘Pacemaster’ and the Omega (Baker Perkins) ‘HSM’ (high speed mixer). These machines had the disadvantage of high maintenance and lack of flexibility in terms of instant sand selection and resin addition changes, due to both mixing troughs always being full of sand.

 

No-bake revolution

Once the Omega 1-series mixer became available, the fast setting acid catalysts could now be employed due to the fact that the single trough design only mixed ‘on-demand’ and could instantly switch from new sand to reclaim sand at the flick of a switch (perfect for facing and backing applications), the resin and acid additions also instantly changing to suit the sand type being mixed. Again, due to the ‘on-demand’ mixing principle employed by the Omega 1-series, mixing outputs as high as 60 tonnes per hour were now achievable, which meant larger floor moulds could be produced using the no-bake process. Productivity also increased due to the use of faster setting times and the high efficiency mixing blade design gave very low chemical addition rates. The no-bake system was now a viable option to all foundries!

The Omega 1-series was well ahead of its time, employing many state-of-the-art features that are still in use today. Some of these new features were the easy to replace ‘half-moon’ blade design, variable geometry blade arrangements with the ability to easily add or remove ‘hold-back’ blades depending on the viscosity of the binder and/or sand grain size. Another radical feature was the introduction of the chemicals from the bottom of the mixing trough, instead of the previous ‘dribble bar’ system of the twin trough mixers. Along with this new method of chemical introduction, the Omega 1-series employed air injection to keep the chemical inlets clear and also help to atomise the chemicals into the trough – allowing very low chemical addition rates to be achieved. All of these features will be familiar to today’s continuous mixer user as they are still considered essential for any modern continuous mixer design.

Omega Sinto is now on its seventh generation of continuous mixer (figs.2 and 3). Key standard features such as double-sided tungsten carbide tipped mixer blades for even longer life (fig.4), auto acid addition on furan mixers, zero maintenance magnetic coupling hardener/catalyst gear pumps, strainers on all pump inlets, air pressure monitoring, a multi-language fully comprehensive user HMI with timer controls, one-touch calibration, in-built maintenance warning messages and sand and chemical usage screen – to name but a few. The mixer even tells you when it needs cleaning or a blade changing!

Mixing efficiency, user friendliness and long-life operation are always at the forefront of any Omega Sinto mixer design and the next generation of Omega Sinto mixer will continue to employ these features as well as offer the latest technology with new innovations to ensure that its users always benefit from the vast experience and forward thinking of the company.

Contact: Omega Sinto Foundry Machinery Ltd, Tel: +44 (0) 1733 232231, email: sales@ofml.net web: www.ofml.net

For copies of the figures, refer to the printed version of this article in the June 2018 issue of Foundry Trade Journal.