Bag Filters: What Are They, How They Work and How They Can Benefit You
HOW BAG FILTERS WORK
Like its name suggests, a bag filter is a small bag made of a filtering material that attaches to a sturdy ring at the opening. The bag sits inside a filter housing and as the bag fills with water, it seeps through the filter's tiny holes, leaving behind unwanted contaminants. When you want high flow rate and basic purification, a bag filtration is a great solution.
WHAT IT FILTERS
A point of entry water system, the primary job of bag filters is to reduce the amount of silt, sand, dirt and other types of sediment in your water. Some bags have a micron rating small enough to filter out some particulates, but they will not clean out bacteria like e. coli or chemicals like chloramines. To remove contaminants like those, additional filter systems will be needed.
Bag filters are unique in that their primary use is in commercial, agricultural and industrial settings. Rarely, if ever, is a bag filter recommended for residential filtration. What makes a bag filter best for these industries is its ability to capture sediment without slowing down the flow rate. If a large piece of sediment is trapped in the bag, water can just flow around it because there is still a plenty of open surface area. This differs from filters that have small openings - if the filter surface is blocked by sediment, the water gets slowed or even stopped. Not only is maintaining flow rate beneficial, but you can remove the filter from its housing and manually remove the trapped material. The reusability is another key benefit of a bag filter.
CHOOSING A BAG FILTER
If removing sediment is your priority, a bag filter system is a great choice. With so many options available, it can feel overwhelming to decide which is right for you. To help narrow the selection process, consider these key questions:
- What type of sediment are you filtering out? By knowing the size of the contaminant, you can determine the micron rating (size of holes in the filter) and media type (polyester, polypropylene or nylon) that will perform best. Additionally, the type of sediment will influence the kind of filter housing you should use. Carbon steel is especially effective in petroleum-based applications, and with soaps and cleaning solutions.
- What is the pH level of the water being filtered? It's important to know the pH of your water because the housing material can be impacted by it. For example, aluminum housings are best used in water with 6.5 to 8.5 pH, so if the water needing filtration has a higher or lower pH, choose a different housing material.
- How much water is being used on a daily basis? If you anticipate needing to filter a high volume of water, you'll need to select a system that can support it.
- What is the maximum and minimum water temperature? Filters perform differently at different temperatures, so selecting a filter that is best at high temps will not be useful if your water temp is low.
- What is the ideal flow rate? Flow rate and micron rating are tied to one another - a higher micron rating has a greater flow - so it's important to balance the sediment size and desired flow rate to create a filtering system that meets your needs.
RECOMMENDED BAG FILTERS
While there are a variety of bag filtration systems available, these three are highly rated:
For answers to filter-related questions, recommendations on the best bag filter, or general drinking water questions, contact us.