1. Setting of booster pump.

Inter-section booster pump should be set up when the outlet pressure of the current section is far lower than the pressure required by the next section of the system; when the output of water between sections is seriously uneven and the water distribution ratio is close to the critical standard, the inter-section booster pump should be selected, and the operation state of the front and rear components should be optimized to reduce the parameters of the first section of the high-pressure pump.

2. The fixation of reverse osmosis pressure vessels.

The pressure vessel of the reverse osmosis system should be installed on a special rack separately, and the two ends of the pressure vessel must have enough space to facilitate the installation and replacement of membrane components. The normal deformation of the pressure vessel can not be limited when the pressure vessel and its pipeline are fixed because the pressure vessel will elongate to a certain extent when the reverse osmosis system is running. At the same time, the membrane assembly may move back and forth in the pressure vessel when the system starts or stops or the inflow changes after the pressure vessel is stretched out. Therefore, special gasket can be used to fix the membrane assembly in order to prevent the membrane assembly from being damaged.

3. Water hammer damage

The high-pressure pump will produce hydraulic impact (water hammer) when starting and stopping. If it acts directly on the membrane module, it will cause membrane bag bond line rupture and other phenomena. Therefore, the reverse osmosis system must design appropriate devices to prevent or reduce the impact of water hammer on the membrane module. Frequency conversion pump, soft start or electric slow open door (electric butterfly valve) are usually used in large reverse osmosis equipment to prevent hydraulic impact. It is recommended to use frequency conversion pump or soft start.

4. Avoid backpressure.

Under no circumstances can reverse osmosis membrane module withstand more than 5 psi of back pressure, excessive back pressure will make the membrane surface of polyamide desalination layer off, resulting in irreversible damage to the membrane module. The back pressure of membrane assemblies can not exceed 5psi.

5. Temperature measurement.

For reverse osmosis system, the inlet temperature will affect many parameters, such as conductivity, water yield, inlet pressure, etc. Therefore, it is suggested to install on-line temperature measuring instrument in reverse osmosis system as a daily operating parameter record, which is convenient to standardize the operating parameters and make a correct judgment on the operation of the system. For the water source with high inlet temperature, temperature alarm device must be set up, when the inlet temperature is over 45 degrees C, the alarm can be issued, if necessary, stop the operation of reverse osmosis system.

6. The temperature compensation of conductivity measurement.

For the on-line conductivity meter installed in reverse osmosis system, the temperature compensation must be able to compensate the measured conductivity to 25C. The installation position of the instrument for measuring the conductivity of water intake should be before the high-pressure pump after the last chemical is added, and the installation position of the instrument for measuring the conductivity of water production should be before the post-treatment process. If the conditions permit, more than one conductivity meter can be installed to measure the conductivity of water production at different locations, and more detailed operating parameters of the system can be obtained. Each pressure vessel should be provided with a separate water-producing sampling port, which is convenient to determine the location of the occurrence when the water-producing conductivity of the system rises abnormally.

7. The measurement of pH value.

It is mainly to measure the pH value of influent, which is an important index to calculate LSI index and judge scaling tendency. At the same time, it can also monitor the pH value of the cleaning solution during chemical cleaning.

8. the measurement of ORP.

In reverse osmosis pretreatment systems using oxidizing and sterilizing or other oxidizing processes, reductants are usually added to protect the membrane components in order to remove the remaining oxidants. The redox potential ORP of the final influent is measured to determine whether the reductant is sufficient. Is there any oxidant in the reverse osmosis membrane module?

9. Installation of pressure gauge.

The pressure gauge must be calibrated before use. The installation of the pressure gauge is:

A, inlet pressure and outlet pressure;

B, raw water pressure, influent pressure and water production pressure;

C, sand filter, carbon filter, safety filter inlet pressure and water pressure.

D, high pressure pump inlet and outlet should have pressure switch.

10. Reverse osmosis system pipeline and high-pressure pump material selection.

The water production pipeline does not pollute the water quality, and the inlet pipeline does not pollute the water. Low-pressure intake pipe and concentrated water discharge pipe can be made of common polymer water supply pipe; high-pressure pipeline and high-pressure pump according to the salt content of intake water, different specifications of stainless steel.

11. Attention to the problem of producing water pressure.

The purpose of setting water production pressure is to make the distribution of water production between sections more uniform and optimize the operation state of membrane modules before and after operation. In the system with very uneven water yield before and after the selection of ultra-low pressure components, high inlet water temperature or waste water reuse, it is often necessary to suppress the first or several stages of water production. In the process of setting up water pressure, we should pay attention to the following points:

A. under any circumstances, the maximum pressure of water production after pressing is not greater than that of 0.3bar.

B. During startup, it is necessary to ensure that the water inlet pressure is raised first, then the water production pressure is held up. When the machine is shut down, the water production pressure is released first, and then the water inlet pressure is lowered. Beware that the back pressure ("back pressure" is defined as the difference between the water production pressure and the water inlet or the concentrated water pressure") causes the peeling of the composite layer and destroys the film properties.

C. And system shall set up check valves and water pressure relief channels to prevent backpressure damage.

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KHN water treatment equipments Co., Ltd.                             www.khnwatertreatment.com