Wet sponge detector is an instrument that combines wet sponge with specific principles to detect surface defects (such as pinholes, leakage points, sealing, etc.) on materials or equipment. It is widely used in coating detection, pipeline leakage detection, container sealing detection and other fields.
Wet sponge detector is a portable device used to detect defects such as pinholes and gaps in insulation coatings on conductive substrates. By contacting the coating surface with a wet sponge and triggering an audible and visual alarm when encountering a leak point, the problem can be located. It is particularly suitable for detecting thin coatings with a thickness of less than 500 microns, with simple operation and battery power supply, suitable for on-site use.
The working principle of the wet sponge detector is mainly based on the following two mechanisms:
Principle of water infiltration: Attach a moist sponge to the surface of the object to be tested. If there are pinholes or leaks on the surface, water will penetrate into the sponge through these defects, making the sponge wet. By observing the humidity changes of the sponge, it is possible to determine whether there are defects on the surface of the object.
Conductivity principle: Wet sponge combines with conductive liquid and moves on the surface of non-conductive coatings (such as paint, resin) on conductive substrates (such as metals). The grounding terminal of the instrument is connected to a conductive substrate. When there is a defect in the coating, the current will form a path through the defect area. The instrument determines the location of the defect by detecting voltage changes and emits an audible and visual alarm.
According to different detection principles and application scenarios, wet sponge detectors can be divided into the following types:
Pinhole leak detector: mainly used to detect pinholes and leakage points on the surface of coatings, such as defect detection of insulation coatings such as paint and resin. Adopting the principle of conductivity, it has high sensitivity and accuracy.
Leakage detector: used to detect leakage problems in water pipelines, containers, and other equipment. By utilizing the characteristic of sponge water absorption and expansion, place the wet sponge in the position to be tested, and determine whether there is water leakage by observing the expansion of the sponge.
Sealing tester: used to test the sealing of equipment or containers, such as car engines, aircraft engines, electronic product casings, etc. The color changes after absorbing the leaked liquid through a wet sponge, indicating the location and severity of the leak.