Electro-optical Metrology:
Typical Applications in the Shipbuilding Industry
Propellor Shaft Alignment
The Micro Alignment Telescope is used extensively for checking the alignment of the propeller shaft and the engine. The telescope is also used to align the marine engine to the stern tube.
Refurbishment of Diesel Engines using boring bar
A common use of boring bar alignment is refurbishment of large diesel engines such as ship and locomotive engines.
The problem: worn bearings need to be realigned before being rebushed and the bush recut using a boring bar.
The solution: a reference line of sight is made by sighting through the front and rear bearing. Bushes (shells) are then placed in each of the bearings and all aligned in anticipation of the boring bar. Normally a hollow boring bar is used and wire targets are placed inside the bar at regular intervals to monitor its straightness as it moves into and along the engine bearings. Wire targets are often used because they do not have any glass and therefore do not refract the light and cause optical errors. If glass is used light will be refracted through each target and error produced.
Without moving the telescope, the telescope is refocused on the boring bar at the various cutting positions to ensure the boring bar is travelling in a straight line and that any sag is removed.
A camera system with dedicated software makes the adjustment of the boring bar easier since the image can be viewed by the operator as adjustments are made.
In some rare cases, a solid boring bar is used. Here a mirror target can be put onto the front nose of the boring bar and the telescope used in autoreflection or autocollimation mode. In these modes a mirror target enables the telescope to be put in line and square to the boring bar. « Back to applications
Propulsion and Steering Systems
Original manufacture of ships uses the Micro Alignment Telescope system to build the propulsion and steering systems. Once sold, these vessels may be used all over the world and eventually require repair or refitting in a country far from the manufacturer’s base. Identical alignment equipment and methods are then used.
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Coal Unloading Conveyor
Coal for power stations comes to its destinations by a variety of transport methods. When a ship is the vehicle used, there comes the problem of discharging the loose cargo in the hold onto the dockside, or waiting land-transport. One of our customers was involved with the design and construction of a screw-type conveyor which dips down into the ship’s hold and withdraws the cargo. Alignment problems arose in the assembly of the several sections which make up the cylindrical head of the machine, allowing debris between the blade edge and the outer casing, resulting in breakdown and replacement sections. Using the Micro Alignment Telescope, Unimount and special targets a series of suitable measuring and alignment procedures was evolved.
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"A" Frame Ship Unloading Structure
This frame structure pivots in large, plain bearings to take cargo on and off the vessel. Misalignment of the plain bearings causes low efficiency, increases stress and premature failure of the system. To prevent these problems the Micro Alignment Telescope and accessories can be used.
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Submarine Applications
Modern military submarines have a number of auxiliary "masts" which protrude from the conning tower. Misalignment creates "noise". Advancements of technology and design of these systems have produced problems in the installation and maintenance of the guide bearings for these "masts". The use of two Micro Alignment Telescopes with a master reference plate and intermediate targets has proved a practical and successful solution to the problem.
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Static Alignment of Ships Weapons Systems using tilt system
The fundamental method for finding static alignment errors is the tilt test or roller path test. This involves measuring the relative tilt between platforms at a series of places. When these individual errors are plotted against the bearings, a sine curve results which identifies the magnitude of tilt at the different positions on the vessel. To achieve the high performance demanded by modern weapon systems, these measurements have to be precise to within a few minutes of arc. Using the CETAMS Electronic Tilt Measurement System allows precise measurement of tilt with no restrictions on movement of personnel or equipment, providing high accuracy measurement at a fraction of the cost of other methods. Click for further details