Introduction to common types of plate heat exchanger gaskets_
Introduction to common types of plate heat exchanger gaskets
The gasket of the 820 plate heat exchanger is an important part of the plate heat exchanger. The working temperature of the plate heat exchanger is essentially the temperature that the gasket can withstand, and the working pressure of the plate heat exchanger is also restricted by the gasket. According to analysis, the length of the periphery of the seal is 6 to 8 times the heat exchange area (for example: a single plate heat exchanger has a 0.5 square meter plate, and the expanded length of the gasket is about 4 meters). The plates are very thin and have poor rigidity, and only elastic materials can be used to make gaskets, and they are not capable of withstanding high temperatures. The gasket should have a compression that can be certified to seal, and the compression should ensure that the groove is not deformed. Next, the editor will introduce several common types of plate heat exchanger gaskets and their scope of application. 1. Non-adhesive gaskets, compared with traditional adhesive gaskets, are complicated, time-consuming, material-consuming, inconvenient to assemble and disassemble, and may even affect human health and cause plate gaskets due to harmful components in adhesives and cleaning agents. The groove is corroded and cracked. Therefore, the application of non-adhesive sealing gaskets is becoming more and more extensive, and in some occasions, local application methods can also be used. Generally, it only takes a few minutes to install (replace) a gasket, which saves 80%-95% and 70% of time and labor compared with pasted gaskets. It is especially convenient for on-site replacement, which greatly reduces maintenance costs and downtime losses. The non-adhesive gasket and the corresponding parts of the plate have special structural shapes. The two are connected by mechanical methods. There are many varieties. They can be roughly divided into two types: 'embedded' and 'clip type'. The applicable temperature is up to 165 ℃ , The pressure is 2.5 MPa. Companies such as ALFA LAVAL, APV, GEA, SONDEX, ITT and HISAKA each have their own patented products. 2. Reliable plate positioning system In order to make the plate and gasket seal position accurate and reliable, prevent up and down or left and right sliding, and extend the life of the gasket, ALFA-LAVAL, APV, GEA, AMBOTE, etc. all use different Plate positioning structure. 3. Gasket material and performance evaluation The weak link of plate heat exchanger is the gasket. Over the years, it has been the focus of public attention and exploration, and some progress has been made in temperature and corrosion resistance materials and their performance evaluation. (1) Nitrile rubber (NBR) is generally suitable for working conditions below 120 ℃. The newly developed high-temperature NBR can reach 145 ℃, and the hydrogenated NBR can reach 160 ℃; EPDM was only used for 150 in the past. ℃, the high temperature EPDM has increased to 160 ℃; Fluoro-propylene rubber (FPM) can be used at 175 ℃; the applicable temperature of graphite laminated gasket can reach 400 ℃, which can well replace compressed asbestos fiber gaskets. (2) Coated gaskets use general rubber or metal blocks as the core, and are coated with polytetrafluoroethylene (PTFE) or fluorinated synthetic materials, etc., which can be used for highly corrosive media or increase the temperature limit. HISAKA is the first to use PTFE-coated NBR gaskets, which greatly expands the application areas of PHE and extends the service life of gaskets. ALFA-LAVAL has used this gasket for double plate welding PHE. (3) With the development of non-adhesive gaskets, the formulation of materials for non-adhesive gaskets must be slightly changed, requiring more stable performance, more durability and better tear resistance. For more knowledge about the gaskets of plate heat exchangers, please visit the official website of Diguang. Welcome to the official website of Diguang to learn more!