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What is a tubular heat exchanger, and why is regular maintenance necessary? A tubular heat exchanger is a device used for efficient heat transfer from one medium to another; the media may be separated by a solid wall, preventing them from mixing, or they may be in direct contact. They are widely used in power plants, chemical plants, petrochemical plants, refineries, and natural gas processing. The heat source in this case is a cooling fluid for thermal engines, namely water, which transfers heat to the air flowing through the radiator (i.e., the heat transfer medium). In almost any chemical, electronic, or mechanical system, heat must be transferred from one place to another, or from one fluid to another. The tube heat exchanger is one of the various types of heat exchangers used in industrial processing systems. They are designed specifically for high-pressure applications—such as those in refineries and chemical processing systems. However, the temperatures and substances they are exposed to mean they are prone to corrosion and mineral buildup. The result is reduced heat transfer efficiency, pollution, and the release of harmful gases in extreme cases. This is why a preventive maintenance plan is essential. So how is a tubular heat exchanger maintained? There are usually 3 steps ； Step 1: Cleaning. Step 2: Machining a new sealing surface on the heat exchanger flange. Step 3: Machining partition grooves on the new sealing surface. Cleaning methods include rod striking, rotary brushing, high-pressure water jetting, and chemical cleaning. The type of cleaning method used depends on how the material is plated and adhered to the inside of the tube. Sometimes, only chemical cleaning/recycling can accomplish this task, but various cleaning chemicals need to be studied, as they can react with the pipe substrate and cause metallurgical problems. It is best to consult your heat exchanger manufacturing and maintenance partner to ensure the best methods are used. A contaminated heat exchanger can cause your process to stop suddenly, resulting in pressure drop issues, reduced flow rates, and decreased thermal performance. In short, the cleaning process involves removing corrosion and mineral deposits. This is usually achieved by combining rod polishing, high-pressure water jetting, and chemical descalers. The cleaning methods for shell-and-tube heat exchangers can be explained in detail in a separate article (we will cover this in a future update). But now let’s focus on processing. After machining new sealing surfaces on the heat exchanger flanges and cleaning them, it is important to ensure that the sealing surfaces on the tube bundle end plates are in good condition. Any signs of corrosion, pitting, scratches, or deformation can compromise the integrity of the flange joint. To prevent this, the sealing surfaces on both the front and back of the flanges should be machined to maintain their integrity. The internally mounted flange surfaces are installed within the flange holes; so how are they fixed at the ends of the heat exchanger? The answer is to use heat exchanger mounting kits (flange fixing plates for the heat exchanger tube sheet), which operate by using bolts installed inside the heat exchanger tubes and expansion elbows. Flange surfaces of this type can be adjusted using heat exchanger tube sheet flange fixing plates. The mounting positions for the machine bed’s main shaft come with fixing screws of varying sizes; the fixing plates for small heat exchanger tube sheets are designed to be installed on flanges with a diameter of 150 millimeters, while those for larger heat exchanger tube sheets can be used with flanges having a diameter of up to 3000 millimeters. Processing partition grooves on the new sealing surface: Some end plates of heat exchangers have partition grooves, whose purpose is to seal the metal plates and divide them into separate chambers. The split grooves are also prone to corrosion, and may require machining back to the base material. You should use milling equipment (such as the LMD2020 portable surface mill mounted on a gantry) to perform this task. The figure below shows an example of an in-situ milling device. Why do more customers choose JOYSUNG? Through its extensive experience and cutting-edge technology, JOYSUNG provides clients with development solutions, analyzing technical construction conditions, confined spaces, possibilities, production disruptions, and more... in order to achieve the results desired by the clients and ensure the success of their projects.