Loss-in-weight feeders

Citation

(2000), "Loss-in-weight feeders", Pigment & Resin Technology, Vol. 29 No. 1. https://doi.org/10.1108/prt.2000.12929aad.008

Loss-in-weight feeders

Keywords H&H Services, Feeders, Process control

What is claimed to be the world's first touch-screen graphics process controller is provided with the loss-in-weight feeders supplied by H&H Services Ltd, designed for the accurate feeding of materials and incorporation of additives into processing lines. The equipment is said to be suitable for use with free flowing granules, powders or even liquids and has the close tolerance and reliability.

The controller is a Merrick MC³ (Plate 4) that can be configured for practically any feeding requirement including both continuous or batching belt or loss-in-weight feeders, and static weighing and belt scale integrators. According to H&H Services unmatched accuracy can be achieved with a full 1,000,000 divisions of resolution applied only to the process material weight. This is said to result in a higher usable weighing resolution than can be achieved with more expensive digital devices while also providing a more accurate material feed at lower feed rates. By eliminating conventional deadloads, any undesirable influence on weighing is reduced and more robust feed components can be accommodated. The need for mechanical counterbalancing is also removed which simplifies the weighing mechanism and minimises plant maintenance.

Plate 4 The Merrick MC³ touch-screen process controller, available from H&H Services Ltd

The company reports that it has supplied loss-in-weight feeders for handling from 0.1 up to 140 tonne/hr with an accuracy of ±0.25 per cent. It also informs us that controlled feed rates can be maintained even where there is mechanical impact shock or an unauthorised load placed on the feeder. Non-scheduled refills are also said to be handled automatically without detriment to weighing accuracy or interruption to the production process.

The Merrick MC3 controller claims flexibility with true graphical representation of product movement and values including feed rate, net weight, and both belt load and speeds etc. It provides data in an organised manner, with a variety of screen choices being available with large typeface display presentation. It is said to be designed for ease of use and a built-in simulator is incorporated for operator training, with interactive touch-screen help prompts also available if required. Self tuning features influencing fuzzy logic and PID control algorithm parameters ensure the feeding process is always reliable, accurate and repeatable.

Details available from: H&H Services Ltd. Tel: + 44 (0)1623 759836; Fax: + 44 (0)1623 755103; e-mail: mike@handh-services.co.uk