PI 068-14 Lohr am Main, 2014-09-04

Improved controller for Rexroth Active Heave Compensation enhances system performance and value

New DS2R electrohydraulic controller with proportional valve is now available for the Rexroth hydraulic axial piston units that function as secondary control devices in offshore winch applications

Bosch Rexroth has introduced an upgrade to the electrohydraulic controller used on the company’s A4VSO and A4VSG hydraulic axial piston components, which function as secondary control units in the Rexroth Active Heave Compensation (AHC) system for offshore winching applications.

Replacing the previous DS1 model, the new Rexroth DS2R electrohydraulic controller features proportional valve technology for more reliability, easier maintenance and lower cost.

The controller is fitted directly to the secondary control unit – axial piston equipment that can serve as both a pump or motor to effectively manage variations in torque on winch drives in rotary AHC systems.

As part of the overall AHC system, the secondary control unit utilizes either a Rexroth A4VSO (open loop control) or A4VSG (closed loop control) axial piston unit to provide the winch torque control when the AHC system is engaged.

Winch control is an essential function handled by the Rexroth AHC system. In offshore operations where loads are being lifted or lowered deep underwater, the winch wire carrying the load is routed from the workboat or rig’s towing winch through the AHC system, which actively compensates for the ship’s movements to keep the load steady in the pitch and swell of the open sea.

The new DS2R controller comes with the Rexroth 4WRPH high-response proportional valve and offers several key engineering and operational advantages, including:

  • High dynamic response, which is crucial in continuously varying wave motion conditions
  • Precise, accurate motion so the loaded winch cable remains continuously “idle” - moving up and down only according to the winch, not the surface wave motion
  • Energy efficiency - through better control of hydraulic components, including the ability to use hydraulic accumulators to recover and re-use up to 70 percent of the secondary control unit’s installed power
  • More reliability and easier maintenance, with a simpler design that eliminates a sandwich filter and is less prone to contamination.

In addition, the Rexroth proportional valve included with the DS2R is capable of handling a greater range of fluid viscosities and requires less pressure drop to maintain control.

Reliability is also improved with a new Rexroth AWXF axial piston unit swivel angle sensor rated for IP67 standards, making it better suited to harsh open-sea operating conditions.

Besides the DS2R, a DS2E version is available without the fitted Rexroth proportional valve. In addition, a DS2S controller is available with a servo valve instead of a proportional valve for test stand or other applications with very high dynamic requirements.

Economical, precise, safe, and energy efficient: drive and control technology from Bosch Rexroth moves machines and systems of any size. The company bundles global application experience in the market segments of Mobile Applications, Machinery Applications and Engineering, Factory Automation, and Renewable Energies to develop innovative components as well as tailored system solutions and services. Bosch Rexroth offers its customers hydraulics, electric drives and controls, gear technology, and linear motion and assembly technology all from one source. With locations in over 80 countries, roughly 36,700 associates generated sales revenue of approximately 5.7 billion euros in 2013.

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The Bosch Group is a leading global supplier of technology and services. In 2013, its roughly 281,000 associates generated sales of 46.1 billion euros. (NB: Due to a change in accounting policies, the 2013 figures can only be compared to a limited extent with the 2012 figures). Its operations are divided into four business sectors: Automotive Technology, Industrial Technology, Consumer Goods, and Energy and Building Technology. The Bosch Group comprises Robert Bosch GmbH and its roughly 360 subsidiaries and regional companies in some 50 countries. If its sales and service partners are included, then Bosch is represented in roughly 150 countries. This worldwide development, manufacturing, and sales network is the foundation for further growth. In 2013, the Bosch Group invested some 4.5 billion euros in research and development and applied for some 5,000 patents. This is an average of 20 patents per day. The Bosch Group’s products and services are designed to fascinate, and to improve the quality of life by providing solutions which are both innovative and beneficial. In this way, the company offers technology worldwide that is “Invented for life.”

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Susanne Herzlieb
Maria-Theresien-Straße 23
97816 Lohr am Main
Phone: +49 9352 18-1573

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