What is the method to locate a leak in the inner tube of a heat exchanger?
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If there is an internal leak in a tube heat exchanger, what methods can be used to detect it? I would appreciate any advice you can offer
Usually, an internal leak occurs, which changes the composition of the medium; therefore, sampling and analysis can be used to determine whether there is an internal leak.
To determine whether there is internal leakage in the tube bundle, an initial assessment should be made based on changes in the system’s pressure and temperature. If there is a leak, it will be from the higher pressure side to the lower pressure side; by doing so, the sampling points can be determined to analyze changes in composition. Generally, pipes are less likely to leak, while the welds on the tube sheet are more prone to leakage.
Leaks in shell and tube heat exchangers occur from the high-pressure side to the low-pressure side. During normal operation, the high-pressure side is usually filled with steam; when leakage occurs on the other side (such as into the liquid material), phenomena such as dilution take place. However, the amount of leakage is limited, making it difficult to detect. It is easy to detect this during startup and shutdown; at such times, the pressure difference between the two sides is small, and by observing the changes in the components on the side that is simpler to monitor, it is possible to determine whether there is a pipe rupture. If it is confirmed that a tube has ruptured, pressure can be applied to the shell side to identify which tube is leaking; then the two ends of the leaking tube can be sealed off.
If the device has not been disassembled, it is possible to increase the pressure on one side and take samples from the outlet on the other side for analysis in order to determine whether there is a leak. If the device is disassembled, an ammonia permeation test on the casing can be conducted to determine whether there is a leak.
We have just discovered a leaking cooler here; it was noticed while listening for water drainage. Even after purging the water circuit (the tube side) with nitrogen, liquid continued to drip out, and upon inspection it was found to be the medium from the shell side. Upon opening the cover, it was found that the weld was damaged.
Component analysis combined with process parameters to determine leaks； Initial leak detection for N2 and air, precise leak detection for NH3 penetration.
1. The composition of the medium will change, allowing for an analysis of these compositional changes. 2. The pressure difference between the two sides is used to determine whether there is a pipe rupture. :victory: .......................
Floor 7 is more specific; for minor leaks, it’s possible to determine them using pressure if they are on the pipe sheet. Otherwise, ammonia testing is required.
Heat exchangers generally involve two or more fluids; under normal conditions, only the temperature or a combination of temperature and phase changes occur, while the composition of the fluids remains unchanged. Therefore, the most direct method for determining heat exchanger leakage is to measure the changes in composition at the inlet and outlet of the heat exchanger, primarily on the low-pressure side. Also, observe the temperature change trend after heat exchange.