Instructions for the installation sequence of reverse osmosis membrane elements in industrial pure water equipment

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　　①Typically, membrane elements are stored in a 1% sodium bisulfite solution; first, they should be thoroughly rinsed with pure water. 　　②The feedwater side of the membrane element is equipped with a concentrated water seal ring; note that the installation direction of the seal ring should be such that its opening faces upstream. The function of the concentrated water seal ring is to ensure that all of the raw water flows into the membrane element without any bypass flow. The flow rate of the raw water itself causes the opening of the concentrated water seal ring to press tightly against the inner wall of the pressure vessel for sealing. If the installation direction of the sealing ring is reversed, the raw water cannot be sealed properly, causing some of it to flow outside the membrane elements. This reduces the flow velocity on the membrane surface, leading to scaling and thus shortening the membrane’s service life. 　　③Confirm that the O-ring is installed in the designated position on the connection fitting. During installation, it is necessary to check whether there are any scratches or contaminants on the surfaces of the O-rings and connectors. Be careful not to install the O-ring twisted. If the connection leaks, raw water will enter the produced water, causing a decline in the quality of the produced water. When installing it on the water collection pipe, the O-ring and the surface of the water collection pipe should be wetted with pure water, distilled water, or glycerin to facilitate installation. 　　④Remove the end plates on both sides of the pressure vessel to install the membrane elements. Install the adapter on the concentrated water side (downstream) of the water collection pipe of the first membrane element. Then, the membrane element is pushed in the direction of the raw water flow and installed inside the pressure vessel. 　　When multiple reverse osmosis membrane elements are installed in sequence, the next membrane element must be prepared for connection to the connectors before the previous membrane element has fully entered the membrane housing. At the same time, be careful not to let the membrane element come into contact with the edges of the pressure vessel to avoid scratches; try to push it into the pressure vessel in a parallel manner. 　　⑤After confirming that the adapter of the pressure vessel is properly connected, proceed with connecting the concentrated water side end plate to the membrane shell. 　　⑥After installing the end plate on the concentrated water side, the membrane element assembly should be pushed again from the feed water side to the concentrated water side to ensure a fully tight connection. Then proceed with the installation of the inlet side end plate; when installing it, care should be taken to measure the gap between the end plate and the adapter. If there is a gap, install plastic shims with an inner diameter larger than the outer diameter of the adapter and a thickness of 1/4”–1/8”, until the end plate cannot be fully installed. At that point, remove one shim and reinstall the end plate.