Remote visual inspection (RVI) is a key element of plant maintenance to help prevent leaks and other accidents. Fast, efficient inspections that don’t impact on reliability can influence plant profitability because shutdowns are expensive. While there are many inspection technologies available, RVI is a popular choice because it provides true-to-life images for confident decision making.
Image Credit: Evident Corporation
A wide range of plant equipment requires visual inspection, each with their own challenges (see table on page 2). This could be anything from the shape of the component (small holes, tight spaces) to its condition (damage, fouling).
| Equipment |
Part to be inspected |
Defects |
Challenges in RVI inspection |
| Pipes |
Connections, elbow joints |
Clogging, cracks pinholes, poor welding, linings |
Confined spaces, dark conditions, image traceability, high temperatures (sometimes) |
| Boilers |
Tube interior, headers |
Clogging, cracks, wastage, poor welding, linings |
Dark conditions, camera instability, reflective surfaces, high temperatures |
| Heat exchangers |
Tube interior |
Clogging, cracks, wastage, linings |
Confined spaces, dark conditions, image traceability, high temperatures |
| Turbines |
Turbine blades, combustion chambers |
Cracks, wastage |
Dark conditions, camera instability, reflective surfaces, high temperatures |
| Vessels / reactors |
Internal pipes, vessel bottoms |
Clogging, cracks wastage, poor welding |
Confined spaces, dark conditions, camera instability, high temperatures, high levels of radiation |
| Valves |
Connections |
Clogging, pinholes |
Dark conditions, reflective surfaces |
The latest generation of videoscopes offers innovative features that address the complicated inspection challenges mentioned above. Faster inspections and better-informed decision-making mean that these videoscopes provide a high return on investment.
Overcoming Accessibility and Maneuverability Challenges
To comprehensively inspect large structures, such as pipes, reactors, or heat exchangers, images of even the hardest to access locations and surfaces need to be obtained. This means that, in RVI inspections, camera accessibility is one of the main challenges. As such, both the dimensions of the scope and the level of control over its movement need to be highly specific.
Easy maneuverability in challenging environments, such as the long, narrow pipes found within heat exchangers, is enabled with the intuitive articulation of the Evident IPLEX NX™ videoscope, shown in Figure 1.
Figure 1. Plant maintenance inspections become easier and faster when using the latest generation of RVI tools, such as the Evident IPLEX NX videoscope. Image Credit: Evident Corporation
The scope tip can be moved with greater control and precision, particularly when navigating around corners, through narrow spaces, or through difficult or tight openings. A joystick is used to control the TrueFeel™ power-assisted mechanical articulation to move the scope’s tip. This saves time when inspecting confined spaces (see Figure 2).
Figure 2. Joystick-based mechanical articulation provides an intuitive way to maneuver in confined spaces. Image Credit: Evident Corporation
The IPLEX™ NX videoscope has an available scope with a 6 mm (0.24 in.) diameter and a length of 7.5 m (24.6 ft), enabling users to inspect tubes up to 15 m (49 ft) long, if accessible from both ends. The 6 mm scope can also be used to inspect narrow tubes thanks to its rigid distal end, which is up to 1.3 times shorter than conventional videoscopes. A 4 mm tip can be used for even smaller tubes and openings.
Improved Image Quality for Better Probability of Detection
Poor image quality can reduce the probability of detection (PoD) of faults, such as cracks, blockages, corrosion, or crystallization in all manner of plant equipment. If missed during the inspection, critical defects could cause leaks or component failure and, consequently, lead to significant downtime.
Several factors determine the level of detail in an image, including light output, camera quality, and image processing (Figure 3). High-quality images for a high PoD are the result of Evident’ more than 100 years of optical experience combined with bright laser diode illumination and a large screen.
Figure 3. PoD improves with bright, even illumination of features and surfaces. Image Credit: Evident Corporation
Furthermore, the IPLEX NX videoscope's noise reduction, sharpness, and saturation control make defects easier to spot.
Image Location and Traceability
It is often necessary to access many narrow pipes to look for evidence of fouling when inspecting a large, complex structure, such as a heat exchanger. This requires the operator to capture many images of similar structures and features.
Knowing which image comes from which area is essential when creating a detailed report. However, figuring out this information and adding annotations to each image when the inspection is complete can be time-consuming and error-prone.
The videoscope’s intuitive software combined with an easy-to-use touch screen interface simplifies traceability. Users can easily add precise locations using the InHelp™ inspection assist tool. Images can also be annotated during the inspection rather than at the end for increased speed and reliability.
Figure 4. With a monitor extension cable, the scope can be operated while the monitor is placed in an easy-to-view area. Image Credit: Evident Corporation
Combating Camera Instability in Large Spaces
It can often be difficult to obtain a stable image when inspecting the interior of expansion vessels or large-diameter pipes due to camera movement. The scope tip needs to remain stable and centralized to take a clear image. Evident’ flex-and-stay guide tubes provide the stability necessary to capture high-quality images.
Inspections in Hard-to-Access Locations
Plants often have complex layouts, meaning certain application areas must be accessed from a difficult location. An inspector may have to pass through several valves, pipes, and expansion tanks before he or she can access a pressure vessel or heat exchanger—and all of this happens in a confined space.
With a conventional videoscope, the monitor must be placed as close as possible to the component being inspected. In a confined space, there may be little or no space to place the monitor, so the inspector needs to carefully consider where to place various items of equipment. This makes simultaneously operating the scope and seeing the monitor particularly challenging.
The IPLEX NX videoscope’s monitor extension cable eases monitor placement by providing the inspection with greater flexibility where they put the monitor. For example, the inspector can position the monitor away from the videoscope in an easy-to-view area (Figure 4). This added versatility enables hands-free operation, even in hard-to-access locations. The optional remote control offers even greater versatility by enabling the inspector to have complete control over their inspection from different locations within the plant.
Summary
A versatile videoscope that can produce clear images regardless of the equipment being inspected is required for plant inspection. World-renowned imaging capabilities and a host of innovative features that solve real-world problems combine in Evident’ IPLEX NX videoscope, helping inspectors save time and produce reliable, comprehensive reports. These features can help improve plant safety and profitability by limiting downtime.
This information has been sourced, reviewed and adapted from materials provided by Evident Corporation.
For more information on this source, please visit https://www.evidentscientific.com/en/