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Translation

"Compress" - The Press Control System

The "Compress" system has been design to work alongside the Press, monitoring its operation and ensuring that it is always working as it should. In Normal Operation the system will try to maintain a constant feed rate to the Press. As the press is a volumetric system this gives the most consistent operational results. However, if the plant operating conditions are such that there is no feed to the press or the material is developing too high a motor load than the system will alter the feed rate to maintain optimum performance. The system also allows a supervisor to set certain limits on what settings the operator may apply. All High load and response times may be altered to suit the particular operating characteristics of the plant.

Compress Features  and Functions: For a detailed description of the following features follow the links to the relevant part of the page.

System Specification AQUA-TROL Normal Operation High Load Protection Low Load and Automatic Start-Up

System Specification The current generation of the Compress system, COMPRESS V, is based, as were it predecessors, on Industry standard PLC architecture. The Compress V system however incorporates much simpler and operator friendly controls, than the previous versions. This makes both routine operation and system set up and calibration much simpler. Compress V employs a new control logic that was developed following highly successfully trials. It aims to maintain a steady plant throughput while protecting the Press against overloads and or feed surges. The COMPRESS system provides continual monitoring of Press operation and regulation of the press feed conveyor and main worm shaft. It will prevent overloads, allows auto start-up and shut down, and gives efficient handling of feed stream variations.

The Compress System can be supplied as a retro-fit control package or as part of a fully integrated panel. This is supplied pre-wired and tested. It is intended for plant control room location and comes complete with all press related starters, inverters, meters and overload protection. A separate remote panel can be mounted near to the press to provide operating data . A variant of the Compress system will also work with an Inverter on the main Press Drive. This allows the speed of the Press to be varied so that it can be set to exactly match the plant operating capacity. This option is especially suitable for single press operation plants or for the end/last press in a line in multiple press plants.

Aqua-Trol

Compress IV also introduces "Aqua-Trol" as an optional extra, this is a system where by the motor load is moderated by controlling the moisture inside the Press rather than by simply changing the feed rate to the Press.

• Provides protection from main motor load surges.

• Reduces Press power consumption and lowers operating temperatures of the Press

• Offsets evaporative moisture losses during pressing.

• Can be used to maintain cake moistures when processing excessively dried feed material.

Normal Operation:

In its normal operating mode the Compress system maintains a constant, operator set, feed rate to the Press.  This provides for optimum Press operation and steady operation of the whole plant.  While running the system is continually monitoring for conditions that might cause the Press a problem and will switch to an alternative control regime if a problem is detected.

High Load Protection:

The press running load is constantly monitored by the Compress system, which will detect high load levels and automatically make adjustments to the Press Operation to control the high loads. There are 3 distinct stages of Press load protection as follows:

1. High Load - The system makes gradual adjustments to the feeder speed in order to reduce the high load whilst maximising press throughput.
2. Very High Load - If the press load continues to rise until it reaches a very high level the system will will take quicker and more drastic action in order to reduce the load to a safe level. This action can prevent a possible full load stoppage of the press or can remove a load surge that could damage the Press.
3. Extremely High Load - If the previous 2 levels of action have failed to stop the press load rising to an unacceptably high level then the press will be shut down immediately, in order to prevent or at least minimise any damage to the press internals, as these extremely high loads are usually the results of foreign objects entering the press internals.

Low Load and Automatic Start-up:

If the flow of feed to the pres stops for any reason, typically as a result of a stoppage elsewhere in the plant then the Compress system will reduce the Press feeder to a safe (lower) speed.  It will then wait at this feeder speed until feed returns to the Press at which time the feeder speed will be progressively increased until the normal operating condition is reached.  Restarting the Press in this manner prevents any overload problems on Start-up.  For example, is some very overcooked and dry material were to reach the Press after a stoppage it might cause the Press to pull very high amps, if the feed rate were too high this might cause the Press to stall.

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(c) De Smet Rosedowns:  August 24, 2007