Heat Exchanger Inspections

Inspecting a heat exchanger using non-destructive testing (NDT) methods like Eddy Current Testing (ECT), Remote-Field Testing (RFT), or Internal Rotary Inspection System (IRIS) is a common practice to assess the integrity and quality of heat exchangers. Each of these methods has its own advantages and is suitable for different types of heat exchangers and specific inspection objectives. Here’s an overview of each method:

Eddy Current Testing (ECT):

1. 1. ECT is a widely used NDT technique for inspecting non-ferrous materials, such as stainless steel, copper, and aluminum.
   2. It is effective for detecting surface and near-surface defects, corrosion, and cracks in the heat exchanger tubes or the tube sheet.
   3. ECT can provide detailed information about the condition of the heat exchanger tubes without the need for physical contact, making it non-intrusive.
   4. It is particularly useful for inspecting small-diameter tubes and can detect defects in both ferrous and non-ferrous materials.

Remote-Field Testing (RFT):

1. 1. RFT is an electromagnetic testing method that can be used for inspecting ferrous heat exchanger tubes.
   2. It is particularly suitable for identifying wall thinning and corrosion in the tubes.
   3. RFT can inspect a large volume of material and is effective for long-range inspections.
   4. It is typically used for tubes with larger diameters and can penetrate through non-ferrous materials.

Internal Rotary Inspection System (IRIS):

• 1. IRIS is an ultrasonic testing method designed for heat exchanger tube inspections.
  2. It involves inserting a probe into the tube, which emits ultrasound waves to assess the wall thickness and detect defects, such as pitting, erosion, and cracking.
  3. IRIS provides high-resolution images and accurate measurements of the tube’s internal condition.
  4. It is suitable for a wide range of materials and tube sizes, but it requires direct access to the tube’s interior, making it a more intrusive method compared to ECT and RFT.

The choice of inspection method depends on several factors, including the type of material, the size and configuration of the heat exchanger, the nature of the defects you are trying to detect, and the accessibility to the internal surfaces. In many cases, a combination of these methods may be used to provide a comprehensive assessment of the heat exchanger’s condition. It’s essential to follow industry standards and guidelines, as well as work with experienced NDT technicians to ensure an effective and reliable inspection.