Small Diameter Flexible Borescope Inspects Orbital Welds
Inspecting very small diameter welded piping requires a highly flexible borescope. Welded sections of sanitary piping or other high purity piping requires a borescope that can make the sharp bends, look at the wall and rotate 360° to view entire welds. A side view borescope should normal be used. Although a forward view borescope with a wide field can be used, but the detail is not as good, and some of the weld can be shadowed depending on the shape of the weld bead.
AIT now offers the super-flex scope which has a range of centering tools that can be added to the tip to maintain alignment in the pipe and focus distance to the weld. These small diaper and highly flexible borescopes can inspect 1/4”Ø pipe to 4”Ø pipe. Standard diameters are 2mm, 4mm, 6mm and 9mm. The 9mm diameter is built with sheathing that is stiffer than the 2mm, 4mm and 6mm diameters. This allows it to be pushed into larger piping.
A large cavity usually requires a large amount of light to successfully conduct a remote visual inspection with a borescope. This simply requires the largest possible borescope. If the borescope can be rigid it will be a simple matter to focus at the required distances.
If the borescope needs to be smaller due to access limitations, multiple access points should be investigated. Tools can be made to deliver a smaller scope to defined points within the cavity. Auxiliary lighting probes can be produced to help deliver light in addition to the light from the borescope probe.
If a semi-rigid borescope is desired for durability, a tip focusing scope can focus at multiple distances. Another advantage of a tip focus scope is the brightness can be better than an equivalent rigid scope. If the access is restricted only in one dimension, probes can be built to take advantage of the space available to maximize illumination. In the case of a slit access, the probe can be built with tubes placed adjacent to carry more lighting fibers and higher resolution image optics.
Typical Rigid Borescope Mirror Tube
Intersecting passages can be viewed using a rigid borescope or semi-rigid borescope with the appropriate direction of view. If coaxial lighting is needed to view into a very small passage, a mirror tube may be needed. However, if the passage is large enough it can be illuminated using separate prisms. If intersecting passages are to be viewed, a mirror tube may be the best way to achieve the direction of view. A mirror tube is a close fitting tube that slips over the OD of the scope to position a mirror at the tip of the scope to reflect the image and illumination at 90°. While mirror tubes are very susceptible to dirt, they offer a coaxial lighting effect that helps to view deeply into a passage at right angles to the scope axis. When the passage is at an angle other than 90°, a mirror tube may not be the appropriate solution.
A flexible borescope may be needed to enter the intersecting passage, and a tool of some kind can be used to help the scope around the bend. Normal practice has been to use articulating borescopes for this, but they are not necessary. Standard borescope products will do a good job if they can be guided into the passages. They can also be customized for special requirements.
Posted in Applications, Borescopes, Boroscope, Rigid Borescopes
Tagged appropriate solution, axis, dirt, good job, illumination, lighting effect, mirror, od, passages, prisms, right angles, scope, small passage, tubes