Leak Detection

Holiday detector

Coatings play a crucial role in protecting metal substrates from corrosion, abrasion, etc. However, even the most advanced coatings can develop defects over time, compromising the integrity of the protective barrier. Early corrosion, in turn, often occurs when “mistakes” have been made in applying the coating layer. The most common cause is blistering of the coating layer.

These blisters can occur as a result of the following three forms:

1. Air entrapment: The surface to be coated has coarse deep pores, this allows a relatively large amount of paint to enter the pore, resulting in air entrapment. Due to heat differential, the air can expand and blisters can form in the paint film. These vesicles can crack, which in turn results in craters

2. Solvent entrapment: If the paint dries too quickly due to the sun, for example, a paint film forms too quickly on the coating. You often then see a wrinkled layer forming on the surface. This layer is dry, but the layer underneath is still wet. Thus, this wet layer may still contain solvents. Because the top layer is already dry, these solvents can no longer “dissipate,” so blisters can form in the coating layer.

3. Stress difference: This often occurs when too much layer thickness has been applied. Excessive coating thickness can also occur when too many new coats of paint have been applied. It is quite possible that there is a layer underneath that was applied 20 years ago, so to speak, this layer will react differently than the fresh coating layer. This new coating layer may not be able to cope with these different stresses, which may cause stress blistering in the coating

It is therefore essential that any pinholes or defects that will eventually lead to corrosion are detected as early as possible. (Pourbaix Diagram)

A first method is, of course, a visual inspection. This involves examining the coated surface for visible irregularities such as cracks, bubbles, or discontinuities, for example. Obviously, this is only possible for “larger” defects. Moreover, this method is also highly dependent on the skill and attentiveness of the inspector.

For ‘microscopic’ holes (pinholes), high-voltage testing is a commonly used method to identify these defects. This non-destructive method involves applying a high voltage to the surface and observing sparks (fault signals) that occur at weak spots or defects. The sparks indicate the presence of a break in the coating.

Ultrasonic

In all industries, compressed air leaks are more common than you might think. In fact, this is one of the biggest causes of energy loss within industry. This not only causes a lot of costs, but can even cause danger to workers!

Ultrasonic leak detection relies on the principle that when water or air flows out under high pressure, high-frequency sound waves are emitted. This sound, which is inaudible to the human ear, can be accurately detected and analyzed by specialized equipment. This allows maintenance personnel to detect compressed air leaks quickly & easily, saving many costs.

Ultrasonic leak detection also has several advantages in this regard:

• Non-destructive: No damage is caused to material being inspected.
• Preventive: Leaks can be identified at an early stage, reducing/preventing potential safety risks, environmental damage and production losses.
• Remote operation: By means of a longe range module, the device can be used for longer distances. This also allows inspection of hard-to-reach or hazardous locations.
• Accuracy: It can provide accurate location of leaks, allowing maintenance personnel to address problems more efficiently

Marking dyes + UV detection

Dyes are widely used in various industries for a variety of applications. The most common of course is for leak detection of pipes, couplings, etc. Here we also have natural dyes, when diluted with water they discolor immediately. There are also UV dyes existing in liquid and powder form. The liquid forms are colorless mixtures and also discolor only when shined on with an ultraviolet lamp.

UV detection has become a valuable tool in several industries with a range of applications to improve safety, quality control and operational efficiency. The unique characteristics of UV light, which lies outside the visible spectrum, enable specialized detection methods that are crucial for identifying, monitoring and addressing various industry challenges.

Thus, in industrial environments, UV lamps are often used for leak detection, quality inspection, contaminant detection, coating verification, fluorescent material analysis and many other applications.