5 Tips to Choose the Right Borescope for Steam Turbine Testing

5 Tips to Choose the Right Borescope for Steam Turbine Testing

Borescope inspection offers a method of visually inspecting the inner pathways of a turbine, such as the gas path, rotor, and impeller blades. Such areas are otherwise quite difficult to reach; therefore, you require intrusive resource equipment to show defects.

The borescope is used to properly inspect the turbines, especially if you do not want to disassemble the turbine. Borescopes are categorized into:

  • Video borescopes.
  • Rigid borescopes.
  • Flexible borescopes.

The performance of a gas or steam turbine equipment directly impacts the industry’s production and financial books. You must be aware of regular inspections and equipment health parameters with the aim of minimizing potential downtime. There are several factors to be considered when selecting the appropriate borescope.

1. Diameter and Length

It is helpful if you chose a borescope of corresponding size and length to the spaces in the turbines. The number and radius of turns will determine the diameter of the borescope required for turbine inspection. If the diameter of the borescope is too large for the hole, it may get stuck or fail to navigate bends in the turbine. The length of borescopes is essential when determining the nature of the turbine pathways; shorter borescopes are more precise than long ones.

2. Illumination

To choose suitable illumination to get the best effect in turbine inspection is vital. When inspecting dark spaces in a turbine, you will require some form of illumination. This illumination features glass fiber that delivers light from an external source. The various surfaces offer different illumination depending on the material. For efficiency, use fitting borescopes that will transmit more light and hence produce better-quality images.

3. Direction and Field of View

The angle of view is important to consider when inspecting turbines. The angle of view varies depending on the location of the observed point of inspection in the turbines. You may look out for angled, flexible borescopes depending on the inspection task. You can use a 90° mirror tube or a rifle barrel for a straight direction of view. A backward 120° borescopes examine hard to reach areas in turbines such as valves. The field of view of a borescope can be wide or narrow and is approximately 37°. The wider the field of view, the lower the magnification of the images.

4. Articulation

Steam turbine testing requires search movements inside the turbines. An articulating borescope is recommended for capturing high-quality images. Tip articulation helps in making fine adjustments to the positioning of the borescope during steam turbine testing. You may also require an articulating borescope if you encounter tight cavities in which a rigid borescope cannot penetrate.

5. Inspection channel

You should keep the inspection area close and choose a shorter tunnel to reduce bending times and the amount of probing you conduct in the steam turbine during repairs. First, the channel from top to bottom should be considered top priority and wide channels. It is also recommended that you used the correct direction of the probe in the channels, especially when conducting steam turbine testing.


Borescope inspection can reveal potential problems that may impose damage to steam and gas turbines. Without an official borescope inspection report, the machines could be working at low-efficiency levels due to various problems. High-quality borescope equipment is used for steam turbine testing to ensure a safe working station.

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