PE flared pipe
DATE：2022/3/9 8:46:23 / READ： / SOURCE：This station
PE flared pipe
With the progress of science and technology and the development of industrial and agricultural production, the production of PE pipes is increasing day by day. As a new type of water supply and drainage material, it has been widely used in urban water supply, farmland irrigation, chemical industry, construction and other industries. At present, the domestic plastic pipe connection method still adopts the backward method of hot socket after fire baking and oil scalding, which is more difficult in construction, high labor intensity, serious energy waste, and difficult to ensure the installation quality, so as to affect the service life of the pipe. Therefore, developing PE flared pipe and sealing connection technology is one of the important tasks in the current plastic processing industry.At present, there are PVC flared pipes and connection technologies in China, but PE flared pipes have not been disclosed. The technology introduced in this example is to use the thermoplastic property of PE, without damaging the appearance quality and physical properties of the pipe, adopt the method of self-control heating and automatic mold setting, strongly expand one end of the pipe into the shape of socket (bell mouth), and then assemble appropriate rubber sealing ring, and insert the pipe of the same specification into the socket to complete the sealing connection of the joint. By changing the mold, flared pipes of different materials and specifications such as PE and PVC can be processed.
PE pipe 1 The grade of HDPE resin is 6100m, the density is 954kg / ㎡, and the melt index is 0.14g/10min. It is produced by the plastic plant of Daqing Petrochemical General Plant. 2. Main equipment (1) plastic pipe expander Changzhou light industrial machinery factory. (2) Dsy-240 electric pressure test pump Zhejiang Haimen pressure test pump factory. (3) Xrz-400 melt index tester Jilin University Science and education instrument factory. 3. Preparation process (1) process flow 1) heating process flow, preheating heating furnace forward - control gear shift to heating furnace reset, hot rolling pliers run, rolling pliers drop, rolling pliers stop, control gear reset - workpiece sent to flaring Station - rolling pliers reset - figure 1-46pe flaring pipe heating process flow 2) socket expansion process flow, Pipe touching 3xk air flared sliding seat in place, machine beating my transposition cylinder to lock Fig. 1-47 process flow of PE flared pipe socket expansion (2) key technologies
1) Pipe flared form. The pipe and pipe are connected by socket, and the selection of flared form is very important. After socket connection, it is necessary to ensure no water leakage, air leakage and temperature change, and no failure under a certain working pressure (generally 0.4MPa), so as to ensure the installation quality of the project and the service life of the pipe. According to the above requirements, combined with the thermoplastic of PE material itself
It is also possible to close the workpiece to the flared sliding seat and move the heated pipe to the flared seat. We repeated the type selection test, and finally determined that the surface quality of the pipe and the thinning of the pipe will not be damaged, so as to expand the form (bell shape) at one end of the pipe. This form of flared pipe has tight socket sealing, small size change and consistent standard.
2) Sealing material. At present, there are many sealing materials, such as rubber, asbestos, hemp and adhesive, which are combined with different materials under different conditions to play a sealing role. We have analyzed and studied in many aspects. It is considered that the effect of using soft rubber sealing material is better. The expansion coefficient and deformation of soft rubber under pressure are large, and its elastic range is wide after sealed connection, so it can adapt to different pressure changes. In order to avoid pushing out the rubber sealing ring during pipe socket, the sealing ring adopts U-shaped structure. During pipe socket, the U-shaped sealing ring is placed in the flared pipe drum. The similarity of geometry makes the sealing ring in good contact with the flared pipe wall, which achieves the effect of tight sealing.
3) To a great extent, the quality of products depends on the mastery of processing art. Molding temperature. Molding temperature is one of the main factors affecting product quality. If the melting temperature range of PE resin is narrow and the molding temperature is too high, the pipe will become a melt and cannot be shaped; If it is too low, it will be difficult to form because the pipe cannot be fully softened. According to experience, the molding temperature of LDPE is generally 160 ~ 200 ℃, and that of HDPE is 200 ~ 250 ℃. The change of surface temperature has a great influence on the quality of products.
② Heating time. The heating time of PE pipe is directly related to the raw material grade, pipe wall thickness and diameter. It is generally directly proportional to the specific heat capacity of PE and inversely proportional to its thermal conductivity. It extends with the increase of pipe wall thickness, but it is not nonlinear.
③ Process flow: pipe heating → pipe expanding → cooling and finalization → finished products warehousing. ④ Main production process parameters (take 162mm diameter HDPE pipe as an example). Heating time of ring at 250 ℃ for 60s ~ 1.2ms
Author：admin