Answers to common questions about reverse osmosis membrane and ion exchange resin (61-70)

61. When replacing NF255-400, which product to choose?

NF270-400 is the most suitable.

62. Can we buy Dow wet components?

Yes, but most of Dow’s FILMTEC components are dry components, and it is still possible to purchase wet components when contacting Dow representatives.

63. How to transfer all ROSA5 calculations to another computer?

The subdirectory in ROSA5 software contains wtdata.mdb, copy it to the corresponding subdirectory of ROSA5 on another computer. The usual main directory of ROSA5 is c:\rosa5\data\

64. How do old FILMTEC components from Dow Dispose?

Since the components themselves do not contain toxic or regulated materials, Dow FILMTEC™ components have no special disposal requirements and can be treated as non-hazardous waste for landfill disposal. However, if the element is used to treat a solution containing harmful impurities, the membrane element may be enriched with toxic substances at this time. At this time, the relevant environmental protection department of the local or national country should be consulted to deal with these specific situations accordingly.

65. Where can I find the warranty information of Dow FILMTEC?

The DIRECTOR Service webpage of the liquid separation section can be found on the warranty information of the Dow FILMTEC™ membrane element or refer to the relevant part of this manual.

66. How is Dow FILMTEC membrane element manufactured?

The Dow FILMTEC™ element is a roll structure, using a highly cross-linked fully aromatic polyamide and polypiperazine ultra-thin composite membrane diaphragm invented by FilmTec, a wholly-owned subsidiary of Dow Chemical.
The Dow FILMTEC ultra-thin composite membrane diaphragm consists of three layers, an ultra-thin highly cross-linked aromatic polyamide separation layer, a microporous polysulfone intermediate support layer, and a high-strength polyester-reinforced non-woven fabric. The nonwoven fabric provides structural support strength. The polyamide functional layer has high water production, the best salt and silica removal rates and unmatched chemical stability. The thick and porous polysulfone support layer has a high degree of Porosity and rigidity can resist compaction under membrane operating conditions.
The Dow FilmTec company passed the ISO9002 certification at the earliest. The Dow FILMTEC components use the most advanced precision manufacturing technology in the industry to ensure highly consistent product quality and high performance. The production of the diaphragm is completely controlled by the automatic diagnosis computer system. The FT30 diaphragm produced by each batch of proprietary technology can only enter the component assembly stage after passing strict online inspection and recording its quality.
The assembly of Dow FILMTEC components is the only rolling process controlled by a dedicated computer to control deviations. The highly automated assembly line ensures uniform winding tension of the diaphragm and the spacing between the leaves of the membrane. All bonding and sealing lines are straight It is also narrow to ensure the effective membrane area, and all important joints use ultrasonic welding technology to strengthen the connection strength and durability.
After assembly, Dow FILMTEC components are subjected to further quality and performance inspections to ensure that they meet our high product standards, including vacuum inspection of adhesive seal lines, and water testing for random inspection of membrane component water production and desalination rates. In order to ensure that the performance of Dow FILMTEC membrane elements is not affected, each element is packed in an oxygen-proof plastic bag and prevents any microbial contamination. Selection of highly consistent components can accurately predict system performance and achieve long-term trouble-free operation.
One of Dow’s major innovations in the manufacture of FILMTEC products is the precision assembly process of components. Dow FilmTec can manufacture membrane components with such precise tolerances, allowing Dow’s component design engineers to adopt a unique “short membrane leaf” component structure , 8” element uses more and shorter membrane blades, the separation efficiency of the element is further improved, the water production is larger, the effective membrane area is better played, the operating pressure is lower, and the production per membrane area The water flux is more uniform and less prone to contamination.
The breakthrough of Dow FilmTec’s manufacturing process is also represented by the unique dry component production technology, which is faster and easier to install. This is because there is no need to rinse and protect the liquid before installation. Although the manufacturing technology and equipment of dry components are complicated, the weight Light and low transportation costs. In addition, dry components are easy to store and store, because it does not have icing problems and has a longer shelf life than wet components.
Dow FILMTEC reverse osmosis and nanofiltration components are used in more applications and applications than any other brand, and their high degree of consistency and reliability have been widely verified in field use for decades. Dow FILMTEC components have been tested by various water sources all over the world for a long time and have an excellent removal rate for dissolved salts and organic matter. Able to operate efficiently at lower pressure, with higher chemical structural stability and pH stability, with the lowest system failure rate, the most stable performance, and the least maintenance service, to achieve “at the lowest cost, get the highest water quality “. It has better system operation economy than other traditional membrane elements.

67. What is the difference between TW and BW components?

The exterior dimensions are exactly the same, the only difference is that the outer sheath of BW is wound with FRP, and the outer sheath of TW is wound with tape. BW is suitable for pressure vessels containing multiple components connected in series, and the pressure difference between the inlet and outlet of the components is large.

68. Dow FILMTEC BW30 - 365, BW30 - 365FR1 and FILMTEC BW30 - 365FR2 What is the difference ?

Their external dimensions are exactly the same. FR stands for anti-pollution (Fouling Resistance). As its name indicates, it is particularly suitable for  wastewater recycling or treatment of complex water sources that are more polluted. It uses Dow’s leading special There is anti-pollution membrane technology. FR1 and FR2 have been upgraded and merged into a unified FR.

69. What is a full – fit component?

The meaning of Dow’s full-fit represents a structural form of the element, but it is still a roll structure, but its outer sheath is no longer wrapped with tape or FRP, but   uses a highly rigid polypropylene grid, which can reduce Even the retention layer between the membrane element and the inner wall of the pressure vessel is eliminated, so this type of element does not require a salt water seal ring. In the occasions with hygienic requirements, the design of full – fit specifically allows a certain amount of bypass flow around the element to reduce the dead water area To prevent the growth of micro-organisms here, but at the same time, in order to effectively reduce the concentration polarization of the membrane surface, a higher water flow is required. All standard membrane elements use brine seal rings, which are used to prevent the inflow of water from bypassing between the outer layer of the element and the inner wall of the pressure vessel. Although there will be a water retention layer (dead water zone), it can ensure that all the influent flows The transmembrane surface has a low inlet water flow rate to effectively reduce concentration polarization.

70. When installing components, what solution should be used to lubricate the pressure vessel?

glycerin. If glycerin is not available, it is better to moisten it with pre-treated qualified water. Do not use any other chemical reagents with unknown physical and chemical properties or industrial and civilian detergents.

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