Dec 19, 2010

NVision's Scanning Saves Invensys 60 Hours in Mechanical Upgrade to Steam Turbine

Invensys Operations Management (IOM) saved 60 hours, or about 5% in man-hours, in a mechanical upgrade to a steam turbine by using NVision's Engineering Service Division to capture precise measurements of valves and other hardware. IOM usually has to spend considerable time field machining upgrade components prior to installation because accurate drawings are not always available. "NVision's laser scanning provides highly accurate measurements, reducing engineering time and eliminating the need for field machining," said Michael Montesinos, Senior Applications Engineer for the Turbo Machinery Group of IOM, Webster, Texas.

IOM, a division of Invensys, is a leading provider of automation and information technology, systems, software solutions, services and consulting to the global manufacturing and infrastructure industries. Its Turbo Machinery Group provides electromechanical hydraulic upgrades to electrical power generation, oil refining, nuclear, pulp and paper, and chemical plants. Drawings are not usually available for these projects either because they have been lost over time or because the OEM that originally installed the equipment closely guards detailed drawings in an attempt to improve their position as a service provider and OEM.

In the past, designers and engineers had to spend extra time in designing the new equipment to account for dimensional uncertainties. After the equipment was built and delivered, measurements had to be taken to determine what adjustments needed to be made to the equipment. The equipment was sent to a local machine shop to make the adjustments. It's important to note that this process needed to be carried out during a turnaround when the plant was shut down for maintenance and improvements. Extending a plant outage beyond the planned timeline typically carries a cost of several hundred thousand dollars in lost generating revenue.

IOM looked into laser scanning in an effort to get accurate measurements from the beginning of the process in order to streamline engineering and potentially eliminate field machining. "We decided to work with NVision because they have considerable experience in reverse engineering process and power plants," Montesinos said. In a recent steam turbine upgrade, NVision technicians visited the plant prior to the upgrade to obtain measurements. The technicians moved the NVision HandHeld Scanner around 16 valves to capture their complete geometry. The NVision HandHeld Scanner is mounted on a mechanical arm so it can move freely around any size part.

NVision provided the geometry of the components to IOM in the SolidWorks file format. IOM engineers and designers used these files as a starting point in designing the upgrade, which saved a considerable amount of time. Based on an earlier test, IOM expects the new equipment to fit perfectly when it is installed so no field machining is anticipated. Montesinos estimates the total time saved on this relatively small project was 60 hours or about 5% in the man-hours normally required for the job. In larger projects the elimination of field machining should make it possible to reduce by several days the time that the plant is shut down for turnaround. "Our ability to accurately reverse engineer the existing plant helps to assure the customer that we can provide the same fit without the original OEM drawings," Montesinos said. "This gives us greater credibility and will help us win additional business in the future."