If you’re inspecting a small, cramped, and dark space, consider getting a borescope to do the heavy lifting for you. The newest models are convenient and easy to use, harnessing the latest technologies to offer a unique view of the internal workings of pipes, engines, and other types of machinery. Understanding how to use a borescope is easier than you might expect. With a little practice, you can leverage these tools to save you serious time and money on the job site.
What Is a Borescope?
A borescope (occasionally called a boroscope, though this spelling is nonstandard) is an optical instrument designed to assist visual inspection of narrow, difficult-to-reach cavities, consisting of a rigid or flexible tube with an eyepiece or display on one end, an objective lens, or camera on the other, linked together by an optical or electrical system in between. The optical system in some instances is accompanied by (typically fiberoptic) illumination to enhance brightness and contrast. An internal image of the illuminated object is formed by the objective lens and magnified by the eyepiece which presents it to the viewer’s eye.
Borescopes are used for visual inspection work where the target area is inaccessible by other means, or where accessibility may require destructive, time-consuming, and/or expensive dismounting activities. Similar devices for use inside the human body are referred to as endoscopes. Borescopes are mostly used in nondestructive testing techniques for recognizing defects or imperfections.
A Borescope can consist of
- Rigid or flexible working length
- Light Source to illuminate the target under inspection.
- Optical system that may consist of a relay lens system, rod lens system, fiber optic image guide a CCD or CMOS camera.
- Eyepiece or Monitor to view the image
What are the Application of a Borescope?
Borescopes serve a multitude of applications including aviation, aerospace, sanitation, automotive, weaponry, metal casting, law enforcement, electronics, refining, and power generation. In order to accommodate a variety of industries, borescopes vary in length, diameter, and functionality.
Large industrial machinery and equipment like turbines need to be regularly inspected and evaluated with the utmost care. Using an optical tool called a borescope allows turbines and machinery to be evaluated without wreaking havoc. Find out more about types of borescopes, borescope inspection, and other uses.
Boroscope Inspection of Gas Turbine
Borescopes are used in many industrial procedures but are commonly used in gas turbine inspection. This procedure can be very dangerous since gas turbines operate at higher temperatures than other turbines (steam). Steam turbines typically operate at 1,200 degrees Fahrenheit, while gas turbines operate at 2,000.
Borescopes allow these gas turbines to be safely inspected during routine borescope services provided by an inspection company. They prevent accidents due to overwhelming heat from the turbines while identifying any unknown issues inside the machine.
How To Properly Use a Borescope?
Each borescope will have its own specific set of instructions for use. Be sure to check the accompanying instruction booklet of any borescope you intend to use. Generally, though, learning how to use a borescope is easy. Start by inserting the tip of the borescope into the space you need to inspect. You can feed the cable in as far as necessary to spot potential issues. High-intensity LED lights at the tip of the scope illuminate the space inside, and the borescope’s monitor will show you live views of the space you’re inspecting.
Borescope uses vary depending on the model in use and the task at hand. For instance, if you are inspecting an overhead air duct, you may prefer a rigid borescope that will hold its shape so you won’t be fighting gravity as you take a look inside. Conversely, if you’re inspecting an engine and need to snake the cable through tight corners, a flexible borescope may be preferable.
What are Some Types of Borescopes?
The difference in optical relay in borescopes creates a few different models. These consist of rigid, flexible, semi-flexible, and video borescopes.
Rigid: Rigid boroscopes are the most affordable type of boroscope. They are commonly used in areas that have direct access to the area in question since they have little to no flexibility. They transmit images using traditional lenses that display through an eyepiece. Borescope inspection services commonly use this rigid type for its image clarity and durability.
Flexible: Also known as a fiberscope, flexible borescopes have fiber-optic lenses attached within a sheath on the device. Although these don’t provide the best quality pictures, they are useful devices for hard-to-reach areas. Be aware that image quality may appear fuzzy or have granulated pixels. The use of flexible borescopes is uncommon in turbines and large machinery because of cost and image quality.
Semi-Flexible: Semi-flexible borescopes are a useful middle ground in between rigid and flexible. Though they don’t cost as much as the flexible type, they do have better picture quality than flexible. Use semi-flexible when minimal manipulation is needed for inspection or inside small tubes and catheters.
A video borescope or “inspection camera” is similar to the flexible borescope but uses a miniature video camera at the end of the flexible tube. The end of the insertion tube includes a light which makes it possible to capture video or still images deep within the equipment, engines, and other dark spaces. As a tool for remote visual inspection, the ability to capture video or still images for later inspection is a huge benefit. A display at the other end shows the camera view, and in some models, the viewing position can be changed via a joystick or similar control. Because a complex fiber optic waveguide in a traditional borescope is replaced with an inexpensive electrical cable, video borescopes can be much less costly and potentially have better resolution (depending on the specifications of the camera).
Costs for high-end video borescopes can range from about $8,000 to $50,000 depending upon manufacturer, options, and specifications. Easy-to-use, battery-powered video borescopes, with 75 mm (3 in) LCD displays of 320×240 pixels or better, became available circa 2012 from several manufacturers for prices between $100 and $400 and are adequate for some applications.
On many of these models, the video camera and flexible tube are submersible. Later models offered improved features, such as lower cost, better resolution, adjustable illumination, or replacing the built-in display with a computer connection, such as a USB cable. Hobbyist models of this type are now available starting at around $10.
Overall, borescopes are easy-to-use devices that provide optimal picture viewings of gas turbines and large machinery. The different types of borescopes allow for multiple advantages during inspections including high-resolution pictures, accurate and detailed coverage of difficult-to-reach locations, and even the aid in the retrieval of foreign objects.
