RO Water System Parts – how do they Work?

4 stage RO system parts

Reverse osmosis or RO is a water purification technology, which uses a semipermeable membrane to remove a larger particle from drinking water. Reverse osmosis can be applied to many things. To purify drinking water is just one example. Reverse osmosis is also applied for desalination, food industry, maple syrup industry, reef aquariums, window cleaning etc.

How does reverse osmosis work?

Reverse osmosis appears to be a complex process. Actually, it is not. In fact, it is a simple and straightforward. We will tell how you how does reverse osmosis work. We hope after you read the explanation, you will have a better understanding of this process. Before we start, here are some important things to know:

  • All of the reverse osmosis processeswork the same way
  • Most reverse osmosis systems look alike
  • All of the reverse osmosis processes have the same basic components
  • The real difference is not in the process, but the quality of the components. Specifically, thequality of the filters and membranes inside the reverse osmosis

Now, let’s talk about the process.

Reverse osmosis is a process which removes dissolved inorganic solids (for example, salt) from a solution (in this case, water).

How does this accomplished?

Let’s say we have a tank of water. One side is filled with saltwater and the other is filled with pure water. The saltwater and pure water are separated by a semi-permeable membrane. Now, we would apply pressure to the saltwater side. The pressure applied is enough to counteract the natural osmotic pressure from the waterside and push the saltwater through the filter.

This will take about 50 to 60 bars of pressure. Because of the salt molecules size, only the smaller water molecules will make it to the other side. Thus, adding fresh water to the pure water side and leaving the salt on the other.

What are the reverse osmosis machine parts?

Although reverse osmosis machine parts can be different one from another, here are the basic parts that are common in RO systems:

  1. Cold water line valve

It is a valve that fits into the cold water supply line. It has a tube that is attached to the inlet side of the reverse osmosis pre-filter. It is the water source for the reverse osmosis system.

RO Water Splitter

  1. Pre-filter(s)

The number of pre-filter used in a reverse osmosis system differs from one another. Indeed, there may be more than one pre-filter used. The most commonly used pre-filter is the sediment filter. This kind of pre-filter is used to remove dirt, sand silt, and another sediment. Other pre-filter, such as carbon filter, can be used too.

APEC RO pre-filters

  1. Reverse osmosis membrane

It is the most important part of the reverse osmosis system. The most commonly used membrane is a spiral wound. There are two kinds, the thin film composite or material (TFC/TFM) and cellulose triacetate (CTA). CTA is chlorine tolerant, while TFC/TFM is not.

Reverse osmosis membrane

  1. Post filter(s)

After leaving the storage tank but before going to the faucet, the water goes through post filter. The post filter is generally carbon. It can be in carbon block or granular form. It is used to remove remaining odors and tastes from the water.

APEC RO post filter

  1. Automatic shut off valve (SOV)

It is used to conserve water. When the storage tank is full, the SOV stops the water from flowing to the membrane.

Reverse Osmosis System Auto Shut Off 4 Way Valve

  1. Check valve

The check valve is located at the outlet end of the reverse osmosis membrane housing. It prevents the backward flow of the water from the storage tank. By doing this, it prevents the membrane from rupturing.

RO check valve

  1. Flow restrictor

The flow restrictor is used to maintain the flow rate required to get the highest quality drinking water. It is also used to maintain pressure on the inlet side of the membrane. The flow restrictor is located in the reverse osmosis drain line tubing.

flow restrictor

  1. Reverse osmosis tank

The storage tank can hold up to 2.5 gallons of water.

APEC RO system tank

  1. Reverse osmosis faucet

ro faucets

  1. Drain line

It is used to dispose of the contaminant and impurities found in the water source

  1. Reverse osmosis machine pump

  2. Reverse osmosis booster pump

The benefits of reverse osmosis

What are the benefits of reverse osmosis? There are many benefits you can get from this system. Here are some examples:

  • It removes contaminants from the water, which makes the water safe to drink. The contaminant, such as lead, is dangerous. Lead toxicity can cause anemia and brain damage to children.
  • It removes parasites
  • It improves the appearance, odor, and taste of the water
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  1. Bryant L Morris says


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