10 considerations for selecting the right borescope

Combining the use of probes, lighting, cameras and sensors to conduct minimally invasive examinations, inspection cameras are ideal for different kinds of testing in otherwise inaccessible locations. With unique qualities such as flexible cabling, light-weight enclosures and high resolution cameras, they have revolutionised the medical field.

These useful properties can also be applied to maintenance, repair and operations (MRO) in industry, where the use of inspection cameras is widespread.-Dismantling complex machinery is often time-consuming and expensive, and so any technology that minimises disruption is invaluable for resolving and preventing problems.

Types of inspection cameras

Although all remote visual inspection cameras work using the same principle, they come in many different forms. Used universally by electricians, engineers, safety experts, mechanics and apprentices during training, inspection cameras offer versatile solutions for targeted and cost-efficient maintenance. Built with the shared purpose of taking images in hard-to-reach places, some of these devices are better suited to industrial applications than others:

• Fiberscopes are thin, fragile and susceptible to damage if used incorrectly. With an articulation capacity limited to a maximum of 90°, they are not appropriate for all applications. As fiberscopes capture and project images indirectly, the image quality can be reduced, unlike other inspection cameras that are capable of capturing digital images.
• Endoscopes are typically used within a medical context due to their flexibility and thinness. Based on the same principle as other inspection cameras, endoscopes could, in theory, be used in industry but in practice, this would not be the most effective or cost-efficient option as they are limited to 90° articulation and have dimmer lights which are used to accommodate the human body.
• Borescopes are available in a number of different variations that can be chosen according to your inspection needs. With a choice between rigid, flexible and video borescopes as well as different length, magnification and size options, these versatile devices are likely to offer the right option for your application.

10 considerations for selecting the right borescope

1. Cable diameter and length

Borescope cables are available in a variety of lengths and diameters, which can complicate choosing an appropriately sized cable. This choice is restricted by component openings, pipes and vents in the machinery being inspected. Purchasing an inspection camera that can accommodate several cable sizes may be advantageous as smart engineers can avoid the need for multiple borescopes of varying widths and potential refitting costs.

2. Rigid or flexible borescopes

• Rigid borescopes typically have smaller diameters which allow for the inspection of very small components and spaces. Using a simple design, economical materials and small inexpensive lenses, rigid borescopes are easy to use and offer high-resolution images of small parts and straight pipes. However, due to their lack of motion and with viewing limited to a straight line, they are not ideal for applications requiring the inspection of irregular internal cavities.

Flexible borescopes enable the inspection camera to be moved in different directions and at different angles. Perfect for curved pipes, ducts and vents, the high mobility offered with flexible borescopes enables them to overcome space limitations and steep angles. Capable of covering both small and large areas, they can perform inspections in a variety of environments with depth and accuracy.

3. Direction of view

The direction of view (DOV) describes a device’s view from the longitudinal axis through the scope’s tube. Specified in degrees, it can be fixed or variable, and potentially adapted by using an interchangeable tip adapter.

• 0° viewing angle – straight forward
• 45° viewing angle – oblique
• 90° viewing angle – side
• 110° viewing angle – retrograde

Borescopes with 90° viewing angles are ideal for inspecting piping and narrow spaces in great detail. However, other applications may require borescopes with broader viewing angles for more comprehensive checks.

4. Field of viewThe field of view (FOV) is the cone of vision that extends from the objective tip. As the field of view widens, more surface area can be seen. However, with a wider field of view, detail typically reduces, becoming less capable of magnification. As the inspected object’s distance from the scope increases, the FOV angle should decrease, improving magnification and image quality.

Whilst certain inspections may require a wider or narrower field of view, the standard for most MRO requirements is approximately 55°.

5. Depth of fieldThe depth of field (DOF) describes the distance from the tip of the tube to the furthest object that appears clearly focused (maximum). The DOF is expressed by a minimum and maximum distance, where the image will appear blurry if the tip is closer than the minimum value. The machinery being tested will dictate the appropriate DOF so that a suitable camera can be chosen depending on the depth of components being checked.

6. Environmental factorsUsed in typically inaccessible areas, inspection cameras must be chosen in relation to their intended testing environment. This includes factors like ambient lighting and vibration. For plumbing, cameras will need to be waterproof whilst those used in engineering applications may need to withstand exposure to chemicals.

7. Memory and storage for photos and videosSometimes it may be necessary to record images and videos from a visual inspection. IIf this is the case, purchasing a borescope with a removable SD memory card to easily download these images will be useful. More advanced borescopes may also be able to run additional analytical software. This capability comes with an increase in cost, so it is worth considering whether it is essential or not.

8. Illumination

Inspection cameras require a light source to illuminate the piping or cavity being examined. The choice of light source is contingent on the intended application. Inexpensive borescopes often use bulbs, which can cause heating and contamination problems – fiber-optic illumination or LED lighting might be preferable for sensitive applications.

9. Availability of accessories

As camera inspection devices can be quite costly, enhancing your device so that it can be used for a greater number of applications may be useful. This can be achieved by using compatible accessories such as:

• Longer camera pipes
• Extension poles
• Magnets
• Hooks
• Mirrors

Using these attachments can maximise efficiency by lengthening the device, retrieving metal items and seeing around corners. Whilst they are available to purchase separately, buying a complete unit with relevant attachments included is advisable as products can vary in quality and design. Inefficient attachments will hinder performance where a magnet is weak, a hook is too small or the accessories are ill-fitted.

10. Ease of use

Inspection cameras should be well designed, comfortable to use and ergonomic in design so that they can be operated with one hand whilst the other is free to guide and control the pipe effectively. Controls should also be within easy reach of the fingers and thumb. In this way you will not have to let go of the camera to take a photo, which could make it move and affect the image taken.

Capable of diverse application and widespread use, the variety of inspection cameras available on the market is extensive. With increased functionality comes an increase in price, and so weighing up examination requirements against cost implications is essential. Borescopes are invaluable for maintenance, repair and operations in industry, enabling checks and examinations without needing to disassemble machinery and incur costly downtime.

The future of inspection cameras

Camera technology is continuously improving, introducing enhancements such as rotatable light connectors, swivel-prism borescopes and panoramic borescopes. As advances in artificial intelligence, video technology and illumination are made, borescopes are being modified to accommodate these changes.

Currently utilised to observe passively, borescope technology is developing with a view to managing MRO needs more proactively. Advancements include working channel borescopes with attachments that work on components whilst inspecting them and UV videoscopes that switch from white light to UV light when conducting dye penetrant inspections.

As demand for increased performance and faster production rises, the use of inspection cameras will only become more prevalent. Borescopes are indispensable MRO tools with machine vision that increasingly exceeds the abilities of humans. Choosing the right borescope has never been easier, provided you have a good understanding of the needs and limitations of the intended inspection.

Recommended products