Reverse osmosis equipment | Reverse osmosis pure water equipment | Reverse osmosis purified water equipment | Water treatment professional manufacturer

Reverse osmosis pure water equipment | Hangzhou Zhongming Industrial Co., Ltd. | Professional water treatment equipment manufacturer
It is a membrane separation technology that uses pressure as a driving force to selectively pass through (semi permeable) membranes. When the pressure applied in the system is greater than the osmotic pressure of the inlet solution, water molecules continuously pass through the membrane, flow into the central pipe through the water production channel, and then impurities such as ions, organic matter, bacteria, viruses, etc. in the effluent flow out at one end, which are trapped on the inlet side of the membrane and then flow out at the outlet end of the concentrated water, thus achieving the purpose of separation and purification. It is a physical desalination technology that separates water molecules from impurities such as heavy metals, colloids, bacteria, viruses, and organic matter through a reverse osmosis membrane under pressure. Water molecules pass through the reverse osmosis membrane to become pure water, and impurities such as heavy metals, colloids, bacteria, viruses, and organic matter are discharged to achieve water purification. Reverse osmosis water production process does not require the addition of chemical agents, is environmentally friendly, pollution-free, easy to operate, stable in water quality, and runs economically. It is widely used in industries such as drinking water, electronics, electroplating, chemical industry, water plants, and beverages.

Working principle of reverse osmosis
Reverse osmosis is a reverse migration movement of permeation, which is a separation method that separates solutes and solvents in a solution by using the selective retention effect of a semi permeable membrane under pressure. The phenomenon of reverse osmosis equipment is common in nature, for example, when a cucumber is placed in saltwater, it will shrink due to dehydration. The process by which water molecules in cucumbers enter a saline solution is called permeation. If a thin film that only water molecules can pass through is used to divide a water tank into two parts, pure water and salt water are injected on both sides of the membrane to the same height. After a period of time, it can be observed that the level of pure water has decreased, while the level of saltwater has increased. We call the phenomenon of water molecules migrating into saltwater through this membrane permeation. The rise of saltwater level is not endless, it will reach an equilibrium point at a certain height. At this point, the pressure represented by the liquid level difference at both ends of the diaphragm is called osmotic pressure.

Process flow of reverse osmosis pure water equipment
raw water tank
1) Function: Overcome the instability of pipeline water supply and ensure the stable and continuous water supply of the entire system; At the same time, it also provides a guarantee for the long-term reliable performance of various devices.
2) Selection: PE material or stainless steel material water tank.
3) Control: The water tank is equipped with a high water level float valve and a low water level switch. It has the advantages of high reliability, low cost, simple structure, and easy installation. When the water level is at a high level, the float valve closes and stops water intake. When the water level is at a low level, the high level float valve opens and begins to inject water into the water tank. At the same time, the low water level switch is disconnected, and the booster pump stops working.
2. Raw water pump
1) Function: Provide necessary working pressure for pre-processing equipment.
2) Selection: Determine the working pressure of the booster pump based on the design pressure drop of each pre-treatment equipment (maximum pressure drop of 0.05Mpa per filtration equipment) and the fact that the pressure before the high-pressure pump cannot be less than 0.5Kg/cm2.
3) Control: Use a regulating valve after the pump to adjust the pressure and inlet water volume.
3. Mechanical filter (quartz sand filter)
1) Function: The raw water first passes through a mechanical filter, where 12-24 mesh fine quartz sand is placed to trap suspended impurities such as flocs and rust in the raw water during this process. Due to the mechanical filter capturing a large amount of suspended impurities during operation, it is necessary to regularly flush and backwash the filter to ensure its normal operation.
2) Selection: Choose FRP material (fiberglass material) container
3) Control: The backwashing operation of the mechanical filter adopts a manual controller, and the filter should be cleaned once a day for 10-20 minutes.
4. Activated carbon filter
1) Function: This process uses an activated carbon filter as a pre-treatment for the reverse osmosis device, which is very important. The reverse osmosis system requires an inlet water index SDI ≤ 5 and residual chlorine<0.1mg/L. To meet its inlet requirements, it is necessary to further purify the raw water to achieve the inlet index of reverse osmosis. Installing a carbon filter in front of a reverse osmosis device has two main functions:
1. Adsorb some organic matter in water with an adsorption rate of about 60%
2. Adsorb residual chlorine in water. Inorganic colloids, organic colloids, and soluble organic polymer impurities with adsorption particle sizes of around 10-20 angstroms, as well as residual chlorine that is difficult to remove in sand filters. The reason why activated carbon can be used to adsorb active substances with particle sizes of around tens of angstroms is due to the presence of a large number of micropores and gaps with an average pore size of 20-50 angstroms in its structure. This structural characteristic of activated carbon allows its surface adsorption area to reach 500-2000m2/g. As the molecular diameter of organic compounds is generally slightly smaller than 20-50 angstroms, activated carbon has a strong adsorption effect on organic compounds. In addition, activated carbon has strong dechlorination ability. Due to the strong oxidizing properties of residual chlorine, it reacts with carbon to produce carbon dioxide and chloride ions, resulting in only a small amount of carbon loss. Therefore, activated carbon dechlorination can be used for a considerable period of time. Activated carbon not only has the above functions, but also can remove odors and pigments from water, improve water clarity. After a period of use, the adsorption capacity of activated carbon decreases and needs to be regenerated or replaced. So, after passing through the carbon filter, the raw water quality can be greatly improved, reducing pollution to the reverse osmosis membrane. The treated water quality can meet the requirements of the reverse osmosis device inlet water quality (residual chlorine<0.1mg/L).
2) Selection: Use fiberglass material container with an expansion rate of 40%.
3) Control: The control of the activated carbon filter adopts a manual controller. Due to the large amount of suspended impurities adsorbed by the activated carbon filter during operation, in order to ensure the normal operation of the system, flushing and backwashing must be carried out every day. The flushing process takes 15-30 minutes for cleaning.
5. Fully automatic water softener or dosing device
1) Function: The process of removing hardness (Ca2+, Mg2+) from water is called softening. This equipment is filled with 001 × 7 strong acid Na ion exchange resin, which replaces calcium and magnesium ions in the raw water with sodium ions to reduce the residual hardness in the raw water to below 0.03mmol/L. The purpose of softening is to prevent scaling on the surface of the reverse osmosis membrane, in order to extend its service life and treatment efficiency.

2) Selection: The water softener is a container made of fiberglass material,
3) Control: The control system adopts the American automatic control valve type. According to the set time/flow rate, the control valve head can automatically regenerate the resin, complete the salt absorption backwash, and forward water injection process. The water softener is equipped with a regeneration tank, and the salt and water levels in the tank should be checked daily, and salt should be replenished in a timely manner (iodized salt and other salt with additives are prohibited).
6. Precision filter
1) Function: Precision filtration, also known as security filter. It is a treatment process for raw water before entering the reverse osmosis membrane device. PP filter element has the characteristics of high filtration flow rate, large pollutant holding capacity, and low pressure loss. It can block impurities of different particle sizes and integrate surface filtration and deep filtration. After a certain period of use, the precision filter may also become clogged. Therefore, the PP melt blown filter element must be replaced after a certain period of time. The replacement criteria are: when the pressure difference before and after precision filtration is between 0.05-0.1Mpa, it should be replaced.
2) Selection: Choose stainless steel containers
7. High pressure pump
1) Function: The high-pressure pump provides the working pressure for the required water production flow rate and water quality of the reverse osmosis system. Make the filtered water reach a pressure of about 10 kilograms after passing through the pump body to meet the inlet pressure of the membrane body and ensure the output of pure water.
2) Selection: According to the required working pressure of the reverse osmosis membrane, a Grundfos vertical multi-stage high-pressure pump is used.
3) Control: When the pointer of the raw water pressure gauge reaches 2KG, press the water production switch to start the high-pressure pump and begin water production. A pressure protection switch is installed in front of the high-pressure pump. When the inlet pressure is below 1KG, the pressure protection switch is turned off and the high-pressure pump stops working.
8. Reverse osmosis pure water equipment (pure water device)
1) Function: The reverse osmosis device is the main part of the purified water production line. This device uses energy-saving composite membrane ESPA type reverse osmosis membrane components produced by Japanese Nippon Denko Group and American Heideneng Company. The ESPA series is a high desalination rate desalination membrane for brackish water. High water flux can be achieved at lower operating pressures, with an average desalination rate of 99.5%.
Due to the advantages mentioned above, ESPA membranes provide a wider range of space for the selection of supporting equipment such as water pumps, pressure vessels, pipelines, valves, etc. And using a motor with lower power can meet the needs of work. At the same time, the high water flux and high desalination rate of ESPA membranes greatly reduce equipment manufacturing costs and system equipment investment expenses, and can save a lot of energy, reduce system operating costs, and improve water quality.
Selection: Heidelberg ESPAI-4040/8040 from the United States. The reverse osmosis device is designed with a water production temperature of 25 ℃ and a water utilization rate of 70%.
9. Water tank (raw water tank)
Function: Reserve reverse osmosis product water and provide stable water supply for the next level system operation.

Control: The water tank is equipped with high and low level switches to control the high-pressure pump and booster pump. When the balance water tank is at a low water level, the booster pump automatically starts to produce water. When the water tank is at a high water level, the high-pressure pump stops working.
10. Boosting pump
1) Function: Provide necessary working pressure for the later stage mixed bed.
2) Control: Use a regulating valve to adjust the pressure and water intake after the pump (manual operation).
11. Purified water tank (finished water tank)
1) Function: The mixed bed effluent enters the purified water tank and is then sent to various water consumption points through the purified water tank.
2) Control: The purified water tank is equipped with high and low level switches to control the water supply pump of the mixed bed. When the purified water tank is at a low water level, the mixed bed feedwater pump starts working to inject water into the purified water tank; When the water level is high, the mixed bed feedwater pump stops working.
12. Fine filtering processor
1) Function: Using a 1 μ m polypropylene filter element, it can effectively trap extremely small particles and kill bacterial corpses inside the pipeline. It has a long lifespan, high flow rate, and high filtration accuracy, ensuring sterile water supply for the production line. After a certain period of use, if the water production of the fine filtration processor decreases due to blockage, the filter element must be replaced. The replacement basis is to replace it when the pressure difference before and after filtration is between 0.05-0.1Mpa.
13. Testing instruments and meters
1) The reverse osmosis host is equipped with a pre membrane pressure gauge and a post membrane pressure gauge to detect the working pressure of the membrane, and is also equipped with a system path operation display. The fresh water flow meter and concentrated water flow meter detect the flow rates of concentrated and fresh water.
2) The reverse osmosis host is also equipped with a conductivity meter and a resistivity meter. Online detection of freshwater quality is both intuitive and convenient, allowing for real-time observation of changes in product water quality.
3) Pre processing is equipped with pressure gauges to observe the operation status of the equipment at any time and analyze its operation status.
Cleaning methods for reverse osmosis equipment

Reverse osmosis technology is increasingly widely used due to its unique advantages. The cleaning problem of reverse osmosis water purification equipment may cause losses to many users with weak technical capabilities, so it is necessary to manage the reverse osmosis equipment well to avoid serious problems.

1. Regularly flushing the reverse osmosis equipment with high flow rate, low pressure, and low pH value is beneficial for removing dirt attached to the membrane surface and maintaining membrane performance. When the SDI value of the reverse osmosis equipment suddenly rises above 5.5, low-pressure flushing should be carried out until the SDI value is adjusted to qualified before starting up.

2. Shutdown protection of reverse osmosis equipment Due to production fluctuations, reverse osmosis equipment inevitably needs to be shut down frequently. Protective measures must be taken when it is temporarily or long-term shut down. Improper handling can lead to a decrease in membrane performance that cannot be restored.

Short term storage is suitable for systems that have been shut down for less than 15 days, and low-pressure flushing can be used every 1-3 days to protect the reverse osmosis equipment. Practice has found that when the water temperature is above 20 ℃, the water in reverse osmosis equipment will become smelly and spoiled after being stored for 3 days, and a large number of bacteria will multiply. Therefore, it is recommended to perform low-pressure flushing every 2 days or 1 day when the water temperature is above 20 ℃, and every 3 days when the water temperature is below 20 ℃. After each flushing, all inlet and outlet valves on the reverse osmosis device of the water purification equipment should be closed.

Long term shutdown protection is applicable to systems that have been shut down for more than 15 days. At this time, protective liquid (disinfectant) must be filled into the reverse osmosis device of the water purification equipment for protection. The commonly used formula for fungicides (composite film) is formaldehyde 10 (mass fraction), isothiazolinone 20mg/L, and sodium bisulfite 1 (mass fraction).

3. Chemical cleaning of reverse osmosis membrane Under normal operating conditions, the reverse osmosis membrane may also be contaminated by inorganic scale, colloids, microorganisms, metal oxides, etc. These substances deposited on the membrane surface can cause a decrease in the output or desalination rate of the reverse osmosis device of the water purification equipment, an increase in pressure difference, and even irreversible damage to the membrane. Therefore, in order to restore good permeability and desalination performance, chemical cleaning of the membrane is necessary.

Generally, cleaning should be done once every 3 to 12 months. If cleaning is necessary every month, it indicates that the pre-treatment system should be improved and the operating parameters adjusted. If cleaning is required once every 1-3 months, it is difficult to determine whether the pre-treatment system needs to be improved, as it is necessary to improve the operational level of the equipment.

Hangzhou Zhongming Industrial Co., Ltd. is a comprehensive company (factory) specializing in the production and sales of water treatment equipment and accessories such as reverse osmosis pure water equipment, ultrafiltration pure water equipment, mechanical filters, manganese sand filters, quartz sand filters, activated carbon filters, anthracite filters, etc. Established in 1195, we have successfully completed reverse osmosis pure water projects for institutions such as Wahaha Reverse Osmosis Pure Water Treatment, Run Run Shaw Hospital Reverse Osmosis Pure Water Treatment, and Youth Treasure Beverage Reverse Osmosis Pure Water Treatment.