The membrane consists of several thin layers or sheets of film that are bonded together and rolled in a spiral configuration around a plastic tub (This is also known as a thin film composite or TFC membrane.) The material of the membrane is semipermeable: it allows water molecules pass through while acting as a barrier to dissolved solids (i.e.: mineral chemical contaminants). When the feed water stream passes across the surface of the membrane, the PurePro molecules penetrate the membrane surface, working their way around the spiral and collecting in the center tube. The remaining contaminants are concentrated and washed from the surface of the membrane down the drain. 

Assume a membrane is semipermeable, allowing water to pass through while being closed to dissolved salts. Place a membrane between two compartments in a container as shown in the figure to the right. Then place a salt solution in one half of the container and pure water in the other half. Now a fundamental scientific principle comes into play. That is, two different concentrations of liquids within the same system will try to reach equilibrium (i.e. the same concentration of contaminants) on both sides of the membrane. Of course the only way for this to happen is for pure water to pass through the membrane to the salt water side in an attempt to reach equilibrium is called OSMOSIS. 

Reverse Osmosis is the reversal of the natural flow of osmosis. In a water purification system, the goal is not to dilute the salt solution, but to separate the pure water from the salt and other contaminants. When the natural osmotic flow is reversed, water from the salt solution is forced through the membrane in the opposite direction by application of pressure-thus the term REVERSE OSMOSIS. Through this process, we are able to produce pure water by screening out the salts and other contaminants.

The raw tap water first flows through a 5 micron particle FILTER[1] to remove dirt, rust and other sediment. The water then flows into a carbon briquette cartridge FILTER[2] which takes out 98% of the chlorine and organic chemicals. The next stage of the process is FILTER[3] 1 micron sediment filter or the Block carbon filter to filter multi-chemical compounds and suspension. [4] The reverse osmosis membrane (TFC) which will separate 95-99% of the dissolved contaminants from the water molecules. The contaminants are then washed down the drain. The next stage of the PPW* series process is the small CARBON FILTER [5] removes the remaining traces of chemicals, tastes and odors. Typical Flow Chart The R.O. water is stored in a 12L TANK[6]. Inside the tank is a balloon-like rubber diaphragm, pre-charged with 0.5-0.7 bar of air. As the tank fills, the air pressure increases and pushes the water out when the faucet is opened. The final element of the PurePro Series system is a POLISHED CHROME FAUCET [7]. It is installed on the kitchen counter or the sink. It is a dual action faucet offering intermittent flow (to fill a glass, hold the handle down) or continuous flow (to fill a coffee pot, lift the handle up).

Reverse Osmosis was originally designed to make sea water drinkable for the navy. It is ideal for anyone on a low sodium diet.

An R.O. membrane has a pore size much smaller than bacteria virus, pyrogen or the cryptosporidium parasite. When functioning properly it will remove all microorganisms from tap water and produce sterile water .

The PurePro System is usually installed underneath the kitchen sink. So installers prefer to locate the equipment in the basement or in a crawl space since the water may stay cooler there, and can be easily run up to the kitchen sink, as well as to a refrigerator & additional faucets in the home.

It only takes a 1/4" tee and tubing to run the water to a refrigerator or a extra faucet. Some families run PurePro system to all of their bathrooms.

There are four major variables to consider:
1. PRESSURE. The greater the water pressure, the better the quantity and quality of the water produced. Water pressure of 4.14 bar ideal. PurePro include one booster pump can make sure the water pressure.
2.TEMPERATURE. 25°C is the ideal water temperature for R.O. 5°C water will cause the production of R.O. water to fall to half of that at 25°C . The maximum water temperature recommended is 30°C .
3.TOTAL DISSOLVED SOLIDS (TDS). The higher the amount of dissolved contaminants in the water, the lower the quantity of water produced. A high level of TOTAL DISSOLVED SOLIDS can be overcome with additional water pressure.
4. MEMBRANE. Different membranes have different characteristics. Some produce more water than others; some have better contaminant rejection capabilities; some have greater resistance to chemical abrasion for longer life. PurePro system include RE1812-70 The Thin Film Composite(TFC) membranes combine the best of these characteristics and are considered the finest membrane in the world.

Under ideal conditions, the RE1812-70 TFC membrane is rated at 266L of production per day (266L at 4.14bar, 360L at 6.9bar). Under the average conditions, the consumer can expect 266-360L of product water per day. But thats still a lot of water for the average households drinking and cooking requirements.

The PurePro System (excluding filters) is guaranteed for 1 years for material and workmanship. All defective parts will be replaced free within the first year. The membrane has a one year pro-rated guarantee.

The three pre-filter cartridges should be changed every 6 months. The first is a 5 micron sediment cartridge. The second is a Carbon Cartridge. The third is a 1 micron sediment filters. (some system comes with the Extruded carbon filter.) Failure to change the cartridge every 6 months may allow chlorine to destroy the membrane. It is very easy to change the prefilters. Just order the needed filters from us and all system come with the housing wrench to open the filter housings so you can maintain your system yourself and feel confident about your drinking water.

One indication is a gradual reduction in water production caused by a layering of minerals and salts on the membrane surface. Another is a gradual deterioration in the quality of water being produced. You my notice a different taste or more white scum on the inside of a pan of water you are boiling. This might mean the R.O. membrane is disintegrating and requires replacement. (Note: Water Quality Tester TDSX1 help you to know when you should change the R.O. membrane.