The chemical polishing of the plate heat exchanger achieves the purpose of leveling and polishing through the oxidation-reduction reaction of metal in a chemical medium. The advantage is that chemical polishing has nothing to do with the hardness of the metal, the polishing area and the structure shape. All parts in contact with the polishing liquid are polished, no special complicated equipment is required, and the operation is simple. It is more suitable for the polishing of complex structure titanium denture stents.
However, the process parameters of chemical polishing are difficult to control, and it is required to have a good polishing effect on the denture without affecting the accuracy of the denture. A better titanium chemical polishing solution is HF and HNO3 prepared in a certain proportion. HF is a reducing agent, which can dissolve titanium metal and have a leveling effect. The concentration is less than 10%. HNO3 has an oxidizing effect to prevent excessive dissolution of titanium and hydrogen absorption. , At the same time can produce bright effect. Titanium polishing solution requires high concentration, low temperature and short polishing time (1~2min.).
When the plate heat exchanger is operating the device, the pressure and temperature rise should be kept as stable as possible. A pre-tightening spring can be added to the clamping stud to compensate for the change in the seal pre-tightening force to avoid leakage; in view of the plate-type heat exchanger The structural performance of the heat exchanger can increase the design pressure by 1.5-2 times when selecting the device according to the construction pressure. When using it, it is best to prevent the impact of the system.
In the application site where this problem has occurred, the method of increasing the thickness of the plate can also be adopted according to the specific situation, and its effect is also very obvious; the device that is operated or idle for several years, the self-aging of the sealing material will affect the sealing performance Reliability, so we must take advantage of the opportunity to quickly replace the new gasket, which is very important.