Flaw detection technology of closed cooling tower outer shell (Part.II)

In the last article, we introduced the magnetic particle inspection technology in flaw detection. Today, we continue to introduce the rest of flaw detection methods for closed cooling tower outer shell.

II. Ultrasound detection.

Ultrasonic detection is a method that use the advantage of ultrasound can penetrate into the depths of the metal materials, and reflect when it reach the edge of flaws.  So we can check the parts by sending the ultrasonic beam from the component surface, when it encountered defects or flaws, the ultrasound will generate a reflect pulse waveform and show it on the screen, according to the pulse waveform, we can judge the defect position and size. Compared with X-ray flaw detection, ultrasonic flaw detection has the advantages of high sensitivity, quick check, low cost, flexibility, convenience, high efficiency and harmlessness to human body. The disadvantage is that the work surface needs to be smooth, and experienced inspectors are required to identify the flaw types, so there is no visual perception of the flaws. Ultrasonic inspection is suitable for large/heavy parts.

III. Dye flaw detection

The basic principle of dye (osmosis) flaw detection is to make use of capillarity to infiltrate the osmotic fluid into the defect, and remove the surface osmotic fluid through cleaning, and keep the osmotic residue in the defect, and then use the capillary action of the imaging agent to adsorb the residual osmotic fluid in the defect to achieve the purpose of testing the defect.

Operation main factors: 1. Influence of properties of penetrant; 2. Influence of emulsifier on emulsifying effect; 3. Influence of the performance of imaging agent; 4. Influence of operation methods; 5. Influence of the nature of defects.

Hazards and protection: there will be injuries, operation is required to wear protective clothing, protective gloves. Industrial nondestructive testing produces radiation, which can lead to infertility and even cancer.

IV. X-Ray flaw detection

This method required professional equipments and personal to operate. So we are not recommding this method.

These are the 4 methods of outer shell flaw detection, we are keep sharing knowledges to help our customers maintance our closed cooling tower products more convenient. Please feel free to contact us if you need more information about our closed cooling tower.