Device for manufacturing double-axis oriented PVC pipe elbow and method for manufacturing elbow

Abstract

The invention discloses a device for manufacturing a double-axis oriented PVC pipe elbow and a method for manufacturing the elbow. The device involves a sleeve which is consisted of a first blank pipeexpansion die, a second blank pipe expansion die, an elbow forming die, a die tail plug cover and a die head plug cover; the first blank pipe expansion die and the second blank pipe expansion die canbe connected to one end of the elbow forming die and used for controlling a blank pipe into a double-axis oriented PVC pipe; the elbow forming die is used for converting the prepared double-axis oriented PVC pipe into a double-axis oriented PVC elbow; and the die tail plug cover and the die head plug cover are used for limiting components of the elbow forming die and prevent the elbow forming diefrom moving. According to the device and the method, due to the fact that the blank pipe expansion dies and the elbow forming die are connected together, the whole production process is continuouslyperformed, after the high-elastic-state blank pipe is subjected to two directional stretching by the blank pipe expansion dies, the blank pipe immediately enters the elbow forming die to be bent and formed, no pause exists in the process, so that the production efficiency is high.

Description

technical field [0001] The invention relates to the field of processing plastic pipe fittings, in particular to the processing and manufacture of biaxially oriented PVC pipe elbows. Background technique [0002] Biaxially oriented PVC pipe (also known as PVC-O pipe) is the latest evolution of PVC pipe, which is a pipe manufactured through a special orientation process. The advantage of biaxially oriented PVC pipe is that the molecular arrangement structure of the material is changed by biaxially stretching the material. PVC long-chain molecules are regularly arranged in the two stretching directions, so that it can obtain high strength, high impact resistance and excellent fatigue resistance. [0003] At present, although the processing technology of PVC-O straight pipe is relatively mature, the processing technology of PVC-O elbow pipe is very complicated, and the reliability of processing is poor, and the scrap rate is high, which leads to PVC-O pipe elbow ( That is, the...

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Problems solved by technology

[0003] At present, although the processing technology of PVC-O straight pipe is relatively mature, the processing technology of PVC-O elbow pipe is very complicated, and the reliability of processing is poor, and the scrap rate is high, which leads to PVC-O pipe elbow ( That is, the use of biaxially oriented PVC pipe elbows) is relatively low

Therefore, in the current PVC-O pipe water supply network, the steel-plastic composite elbow is usually used for connection at the turning point. However, the steel-plastic composite elbow has certain shortcomings, such as relatively expensive price and short service life (usually no more than 20 year) etc.

[0004] The main reason for the complicated processing technology of PVC-O elbow is that when bending PVC-O straight pipe, it is necessary to heat the PVC-O straight pipe to a thermoplastic state before it can be bent, while PVC-O The straight pipe itself is obtained by heating the PVC-U straight pipe (that is, the blank pipe) to a thermoplastic state, and then expands radially and stretches axially through ventilation, so when it is bent, the PVC-O straight pipe is heated again , the pipe is prone to de-orientation and retraction, especially when the heating temperature is closer to the temperature required for the thermoplastic state (about 90°C), the phenomenon of de-orientation and retraction is more serious

Therefore, this makes the current PVC-O elbow processing technology very complicated, and it is difficult to control the quality during the processing process, resulting in a high scrap rate and it is difficult to be widely used.

[0005] Due to the excellent performance of PVC-O pipe itself, such as high strength, high impact resistance and excellent fatigue resistance, in PVC-O water supply network pipes, PVC-O pipe elbows are not used for bend connection, but It is a helpless move to replace it with a steel-plastic composite elbow

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