Your experienced partner for failure-free and stable operation:

kmo turbo GmbHFriedrichstr. 59, 88045 Friedrichshafen, Germanyinfo@kmo-turbo.de, Phone: +49 7541 95289-0www.kmo-turbo.com | www.kmo-vibro.com | www.compressed-air-management.info

© kmo turbo GmbH | Subject to modifications without notice | Edition 09/17 | PN 069101702 | www.lake-of-consens.com

Reverse-flow Protection for Turbocompressorsbased on Siemens Simatic S7-120 005-1/0

Uncompromising Reliability • Un

iver

sally Applicable

•

Exceeds API Sta

ndardSTATE OF THE ART

“A turbocompressor surges”, if the operating point of the compressor leaves the stable area of the characteristics map, either due to a reduction of the flow or due to an increase of the discharge pressure. Surging is characterized by a cyclic flow and reverse flow of the compressed medium, and is accompanied by high vibration, pressure surges and a rapid temperature increase within the compressor. Even after a short period, persistent surging can lead to severe compressor damage.

Particularly axial compressors and radial compressors with open impel-lers are at risk. The flow malfunction can have disastrous effects, even on the downstream process.

The reliability of reverse-flow protection is provided due to the fact that, in addition to the

absolute values, also relative changes are monitored.

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Operator Benefits

� Industrially tried and tested standard components available world-wide

� Diversity of the redundant surge detection provided by monitoring of up to four transmitter signals with signal behavior typical to surging (exceeds API 670)

� Three-step reverse-flow protection (partial opening, full opening, shutdown) protects the compressor and addition-ally still allows operation of the downstream process

� Unique diagnostic functions for the failure analysis provided by continuous recording of the surge-relevant signals (diagnostic memory)

� Easy integration with higher-level controls via Profibus, Modbus TCP etc.

� Parameter setting, visualization and startup by using any network-compatible device (PC, tablet, smart phone)

� Thanks to a web-based user interface, no operator software is required

Why both, Anti-surge Control and Reverse-flow Protection?

The anti-surge control ensures a stable operation. When the surge limit is approached, the flow of the compressor is kept at the lowest possible value due to a controlled opening of a blow-off valve. If this control intervenes too late or not at all, the compressor will inevitably surge. Only then the reverse-flow protection is activated. Its task is to then prevent damage caused by persistent surging using appropriate control interventions.

A reliable anti-surge control is dependent on several measuring signals. Due to the fact that these signals may be susceptible to failures, an anti-surge control alone does not provide a com-prehensive form of protection. Most of the measuring errors are caused by leaky sensor lines, by sensor lines in which liquid has accumulated or by a drift of the zero point or measuring range. The surge limit is influenced by temperature, molecular weight and speed, but also by coating and wear of the blading. Not all of these influencing factors can be recognized and corrected by an anti-surge control.

Thus, only the application of an overriding reverse-flow protection ensures maximum security of the compressor.

Perfect combination

More protection is provided by kmo turbo’s reverse-flow pro-tection due to a significant increase in detection reliability.

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More Data – more Value

The high level of surge detection reliability is based on the expansion of the monitoring spectrum and the diagnostic memory. Hence, several indicators are considered for the detection of surging. The industrially proven Siemens S7-1200 with Ethernet interface, or optionally also with Profibus, is used as a control hardware.

Multi-Channel Surge Detection kmo turbo simultaneously monitors four transmitter signals for signal behavior typical to surging. Both, the minimum and maximum absolute values, as well as the positive and negative rate of change are monitored. A transmitter signal that is falsi-fied due to a leaky sensor line will also show behavior typical to surging (fast changes) and is detected by the kmo reverse-flow protection. Hence, kmo turbo presents a remarkable increase in the reliability of compressor surge detection and exceeds the API 670 requirements by far. No separate transmitters are needed for the reverse-flow protection, because the anti-surge control transmitters should be used.

Diagram of a turbocompressor featuring a kmo reverse-flow protection system

Monitoring criterion

Absolute values Rate of change

MIN MAX negative positive

dp (volumetric flow)

Discharge pressure

Suction pressure

Suction temperature

Current/power

Failure-relevant signals and their indicators typical to surging

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Focussing on the entire Process

The kmo reverse-flow protection operates in multiple steps (partial opening, full opening, shutdown). Thanks to the par-tial opening function, in most cases the production process downstream the compressor can still be continued, even after a first surge occurred. In general practice, a reaction to surge is usually delayed on the assumption that the anti-surge control would still manage to correct the unstable condition. However, surging generates such extreme signal jumps that it cannot be corrected, but may even lead to an escalation. The partial open-ing function of the kmo reverse-flow protection is immediately activated upon the first surging.

The recordings of the last 50 surge events, which can be up-loaded from the diagnostic memory (200 sec with a temporal resolution of 200 msec), make it easy to recognize the cause of surging.

Versatile Application

The kmo reverse-flow protection can be used on any turbocom-pressor, axial and radial compressor, with various process gases, water vapor et cetera. kmo controls are successfully in use all over the world. Counted among the customers are both, machine manufacturers and plant operators.

Monitoring criterion

Absolute values Rate of change

MIN MAX negative positive

dp (volumetric flow)

Discharge pressure

Suction pressure

Suction temperature

Current/power

4 Channels3 Steps

Competent and approved

kmo turbo is based on decades of experience and offers pro-fessional support for failure-free, stable operation:

� Reverse-flow protection � Anti-surge control � Centrifugal compressor audit

� Vibration diagnosis and diagnostic systems � Vibration monitoring � Compressed air master control � Troubleshooting � Operation optimization � Commissioning � Retrofitting

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Unmatched Transparency

Über die webbasierte Benutzeroberfläche kann die Steuerung The control system can be intuitively configured and parameter-ized via the web-based user interface. Both, the current and the recorded signal curves, can be visualized. All of the screen views can be saved as PDFs.

Automatic Data Storage

The relevant operating values, along with date and time, of the last 50 surge events are automatically stored; as well as the triggering criterion and the achieved status of the three-step control system. The pre- and post-history of the surging trend can be uploaded via simple mouse click.

Surge as Trend Display

The signals of the last 50 surge events are displayed over a period of 200 sec., divisible in pre- and post-history recordings, and can be evaluated cycle for cycle by zooming and by using the cursor.

The values can be displayed optionally in either dimensioned or percentage form. The displayed gradients are the basis for the monitoring parameters. The data are exported by a simple mouse click (e.g. to Excel).

Simply way

better76

TurbocompressorAudit

Experience has shown that the parameters set during commissioning of a compressor do not provide a long-term guarantee for secure, stable and efficient operation. The initially prevailing conditions may change through time, e.g. due to polluted coolers, measurement drift, wear or failure of individual components et cetera. kmo turbo provides a compressor auditing service, recording all relevant values so that an up-to-date com-pressor map can be created. Clear recommendations of action are given for improvement and optimization of the operation.

Monitoring in Real Time

The online graphic display is an ideal tool to determine the surge limit. Both, the high-resolution analog values (dimensioned or percentage) and the status of all binary control signals, are displayed.

Clear Settings

All control parameters can be entered easily and intuitively. The parameters are stored in the control system and are safe against power failures. The entire overview can be stored and printed.

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Your experienced partner for failure-free and stable operation:

kmo turbo GmbHFriedrichstr. 59, 88045 Friedrichshafen, Germanyinfo@kmo-turbo.de, Phone: +49 7541 95289-0www.kmo-turbo.com | www.kmo-vibro.com | www.compressed-air-management.info

Karl MorgenbesserTurbocompressor Expert

karl.morgenbesser@kmo-turbo.de Phone: +49 7541 95289-10

Kai Mayfarth Automation & Controls

kai.mayfarth@kmo-turbo.de Phone: +49 7541 95289-14

Compressors should be equipped with two independent systems: an anti-surge control and a multi-step reverse-flow protection, which can reliably intervene whenever necessary. This allows you to protect both, your compressor and your process.

© kmo turbo GmbH | Subject to modifications without notice | Edition 09/17 | PN 069101702 | www.lake-of-consens.com