Recently, a customer has reported a problem of low water output rate after using purified water equipment for a period of time. Today, the editor will provide a detailed answer to this issue: in general, the phenomenon of low water output rate and high pressure in purified water equipment is mainly caused by instrument reading errors, temperature, inlet conductivity, water mixing side pressure, pressure difference, membrane element flux attenuation, membrane element pollution, and untimely maintenance. The pressure gauge and flow meter of the purified water equipment were not calibrated before use, resulting in inaccurate readings. The installation position of the pressure gauge is far away from both ends of the pressure vessel, and its reading contains pressure loss in the pipeline. However, when used as the inlet pressure, it will cause the inlet pressure to be low, resulting in low water production.
When the inlet water temperature is lower than the initial design, a decrease of 3 ℃ in the inlet water temperature of the reverse osmosis equipment will result in a decrease of about 10% in water production. When the inlet conductivity is much higher than the design value, for every 1000 ppm increase in sodium chloride solution, it will cause an increase in osmotic pressure of about 11.4 psi. Under the same inlet pressure, the water production of reverse osmosis equipment will decrease. Under the same inlet pressure, due to the installation of pressure suppression on the water production side or the small size of the water production pipeline and the high distance of the delivery point, there is a greater resistance, resulting in a decrease in net pressure and water production. Under normal circumstances, for a six core 8040 membrane element, the pressure difference between the two ends is approximately 3-4 bar. If the design of the pipeline is unreasonable, it will result in significant pressure loss or incomplete closure of the secondary concentrated water discharge valve, which will reduce the net pressure and water production of the reverse osmosis equipment.
If the wet membrane elements are not properly stored or if protective measures are not taken after they are installed in the system, causing the membrane elements to dry out, resulting in a significant decrease in flux or no flux, leading to a decrease in the water production of the reverse osmosis equipment system. The operation of reverse osmosis membrane components requires good water supply. Before the water enters the reverse osmosis membrane components, it needs to undergo front-end treatment such as quartz sand, activated carbon, and softener. If the water quality is too poor, it can easily cause scaling, pollution, or even damage to the membrane components. The main reason for low water production and high pressure in purified water equipment is membrane fouling.
After using the purified water equipment for a period of time, if the corresponding daily maintenance operations are not carried out, the quartz sand, activated carbon, and front filter of the softener are not maintained properly, and the security filter element is not replaced in a timely manner, or not replaced, the filtration performance will decrease, resulting in a decrease in water output rate.
