During commissioning of the hydraulic station, the return oil temperature rose from 45°C to 62°C within half an hour, while the cooling water valve was already fully open. After disassembly and inspection, it was found that oil sludge and rust debris had accumulated between the tube bundles of the original shell-and-tube heat exchanger. Cleaning required removing the end covers and extracting the tube bundles, with a shutdown of at least 6 hours. This phenomenon is not uncommon in compact, continuously operating hydraulic lubrication systems, and it is also a factor to consider during design and selection.
The diffusion-bonded plate heat exchanger is made of stainless steel plates joined into an integral unit by vacuum brazing or laser welding, with narrow channels between plates and no dead corners. Compared with a detachable plate type, it requires no sealing gaskets and has no risk of leakage due to gasket aging; compared with a shell-and-tube type, the heat transfer area per unit volume is increased by about 3 to 5 times, but it cannot be mechanically brushed. The YBJ-50 is designed with a chemical cleaning interface, and the cleaning agent must be diluted according to the instructions to avoid reacting with the plate material. Selection personnel should evaluate the fouling tendency of the medium: clean or lightly fouling conditions can extend the cleaning cycle, while media containing fibers or particles require pre-filtration.
This model is suitable for heat exchange of clean or lightly fouling liquids and gases, such as hydraulic oil cooling, domestic hot water preparation, and process fluid heat recovery. The plate material is usually 304 or 316L stainless steel, with a design pressure of 2.5 MPa and a design temperature of -40°C to 200°C. Compared with the shell-and-tube type, the diffusion-bonded plate heat exchanger has slightly weaker adaptability to sudden temperature changes, and thermal shock conditions need to be checked during selection. Connection methods include flange, thread, and welding, making it easy to integrate into different piping systems.
First confirm the medium type and flow rate, and calculate the required heat transfer area; then check the design pressure and temperature to rule out out-of-limit conditions; finally evaluate the cleaning cycle and shutdown cost to determine whether to add standby equipment. The YBJ-50 heat transfer area covers 1 to 20 square meters, and a single unit's heat exchange capacity can meet the needs of small and medium-sized hydraulic systems or district hot water demand.
