Visual Inspection

Visual Inspection, also known as Visual Testing (VT), is the oldest, most versatile, and most commonly used non-destructive test (NDT) method. Used alone or in conjunction with other test methods, qualified visual inspection is a reliable and highly cost effective tool for quality control. It is simple, easy to apply, quickly carried out and usually low in cost. The basic principle used in visual inspection is to illuminate the test specimen with light and examine the specimen with the eye. In many instances aids are used to assist in the examination. Visual inspection can be used for internal and external surface inspection of a variety of equipment types, including storage tanks, pressure vessels, piping, and other equipment Visual inspection is sometimes carried out in conjunction with the following devices

Magnifying Glass- Generally consists of a single lens for lower power magnification and double or multiple lenses for higher magnification.
Magnifying Mirror- This one is a concave reflective surface, such as a dental mirror may be used to view restricted areas
Microscope- It is a multiple element magnifier, providing very high power magnification, is used for the inspection of parts removed from the aircraft. Some portable units are also used to evaluate suspected indications found on the aircraft.
Borescope- Borescope is a precision optical instrument with built-in illumination. Borescopes sometimes called ‘endoscopes’ or ‘endoprobes’, which consists with superior optical systems and high intensity light sources, some borescopes provides magnification option, zoom controls or accessories.
Flexible Fibre Optic Borescope- Permits manipulation of the instrument around cameras and through passages with several directional changes.
Video Imagescope- The video Imagescope is similar to a Fibrescope with the exception that video camera and its connections have replaced the image bundle and a TV monitor has replaced the eyepiece. This image may be magnified for precise viewing.

Remote Visual Inspection

RVI is the inspection of objects or areas usually inaccessible to the eye without disassembling surrounding structures or machinery. It allows inspectors to discover hidden discontinuities before they may cause major problems, e.g. poor welding, surface defects, corrosion pits, general condition, degradation, blockages and foreign materials. Remote are commonly used where distance, angle of view and limited lighting may impair direct visual examination. RVI equipment penetrates remote places, utilising small openings and sending images directly back to the observer or to a video monitor. Remote Visual Inspection is mainly used as a backup tool to verify the results of other inspection techniques. Latest videoscope systems come with digital stereo measuring capability for accurate, three dimensional defect measurement at any target angle. By utilising stereo measurement system area, depth and distance between reference points, particular discontinuities can be measured. It can be easily configured to inspect behind walls, small vessels through openings, unreachable areas of vessels, inside ceilings, in and around pipes and machinery, under vehicles and aircraft as well as the ducts work in HVAC systems.

Applications

Gearbox Inspection.
Orbital Weld Inspection.
Headers, water and steam lines, pumps, valves, heat exchangers tube, etc. in power plant, refinery and processing industry.
Wind turbine blades and gearbox.
Engines of ship and aircraft
Nuclear Power Stations – contaminated areas
Any areas where it is dangerous, small or costly to view directly
Reduces or eliminates need for Confined Space Entr

Advantages

Portability
Immediate result.
Minimum special skills.
Minimum part preparation.
No disassembly or lost production time for in-service inspection
Recording for future reference
Removes humans from potentially unsafe conditions
Reduces or eliminates need for Confined Space Entry