In the irrigation industry, self cleaning and automatic backwash filters are two pieces of technology that have made large-scale irrigation applications far more efficient and environmentally friendly. Not only do these irrigation filters treat runoff rainwater or farm water, but they are also cost-effective.
Self cleaning filters and automatic backwash filters are irrigation filters that automatically expel hard, soft, and fine contaminants in the water. This ensures that your plants get clean water consistently. Self cleaning filters are low maintenance, making the overall cost of these devices more economical.
If you’re curious as to how they can help you run your irrigation system, these automatic irrigation filters have a lot to offer. There are plenty of benefits to irrigation filters, but these particular choices minimise maintenance for agriculture and other large-scale growers.
Read on to learn all about self cleaning filters.
Table of Contents
What Is a Self Cleaning Filter?
A self cleaning filter is an automated device that removes debris using a pressure sensor. This system is much better for your plants as the water they will receive is cleaner and better for them. Self cleaning filters often last significantly longer than other standard filters.
A self cleaning filter uses a screen filter with relatively larger holes to strain coarse particles. Downstream, a screen filter with finger holes catches the smaller particles. Naturally, when water is treated well, it flows smoothly. However, when it has debris or when it requires cleaning, the water pressure changes. A sensor then sends signals into the device when the pressure changes. That’s when the self cleaning process starts.
There are two major kinds of self cleaning filters, namely a mechanical one and a tubular backwash filter. The filtration system for both of them runs even while the device is in operation, but they differ in how they start self cleaning. A mechanically cleaned filter uses a spring-loaded cleaning disc that wipes the housing. Meanwhile, a tubular backwash filter runs a reverse vacuum to expel the debris.
A self cleaning filter makes water treatment and the irrigation process better and more efficient. It addresses issues such as contaminants (sediments and particles), taste, odour, pH, and unneeded elements in water like iron, chlorine, fluorine, arsenic, and manganese. Additionally, not only does a self cleaning filtration system ensure that your crops get ample water, but it also reduces maintenance costs as debris can damage your device and wear out filters more easily.
It is especially useful in large-scale irrigation and remote sites or areas that don’t require constant manpower or operator intervention. When using farm pond water for irrigation, this type of filter can be a convenient choice.
What Is Automatic Backwash?
Automatic backwash is a type of self cleaning filter that uses reverse pressurised fluid to treat water. Backwashing is also sometimes called regenerating.
Automatic backwash uses several different media, like sand, greensand, granular carbon, granular manganese dioxide, etc. These are used to filter different types of contaminants in the water.
How Does Automatic Backwash Filter Work?
Automatic backwash filters undergo three cycles, namely water filtration or service, backwash, and rapid rinse.
1. Liquid enters from the bottom of the housing (or tank), and it flows from the outside in, through the medium or media. The media (which can be several filters for particular sediments) then gets the contaminants to settle at the bottom and clean water is released through the riser.
2. When the sensor experiences a change in differential pressure or when the system is programmed at a pre-set time, the system can start backwashing the contained water. The pressurised fluid is sent into the housing, and the contaminants in the filter bed are sucked out through the control valve.
3. A rapid rinse happens afterwards that lets the filter bed settle into place again so that service continues.
Pros and Cons of Automatic Backwash Filters
When deciding on whether an automatic backwash filter is right for your system, there are a lot of things to consider. There are many benefits associated with backwash filters, but they have their own downsides you need to think about before a backwash filtration system.
Pros of Automatic Backwash Filters
Automatic backwash filters are very common, and provide a range of benefits including:
• Low Maintenance – Because these systems work automatically, it drastically reduces the amount of manual maintenance you need to do to keep them running.
• Long Life Span – These systems have a remarkably long service life, and will last for years without significant wear and tear.
• Versatility – They can be used for multiple types of water treatment needs, meaning it can solve a variety of water treatment issues.
• Capacity – The bags have a large holding capacity, which makes them a more convenient choice.
• Simple Assembly – Some (if not most) backwash filters are easy to assemble and reassemble, meaning that if you buy a new system or want to change an existing one, with a little bit of time and patience, you can do it yourself. Of course, it’s always best to have a local irrigation specialist take a look at it, to save you time and effort.
Cons of Automatic Backwash Filters
Although automatic backwash filters can add value and convenience to your irrigation system, they have some issues. Disadvantages of automatic backwash filters include:
• Maintenance Costs – Bags and cartridge filters or media need to be replaced, which can add to the maintenance costs
• High Disposal Costs – As backwashing can produce large amounts of wastewater due to the volume and frequency it operates
Does a Self Cleaning Filter Need Any Maintenance?
No, self cleaning filters don’t need dedicated maintenance, although they will benefit from a quick check up every six to twelve months. Because they are self cleaning, you won’t have to worry about scale or grime build up, but a yearly check up can help monitor for damage or larger issues.
All machines need maintenance, especially preventive maintenance. The same goes for self cleaning filters. The good thing about self cleaning filters, however, is that they don’t require as much maintenance as other manual machines. An annual or bi-annual inspection of self cleaning filters is enough to ensure optimal performance.
What Can a Self Cleaning Filter Be Used For?
Primary uses for self cleaning filters are in water treatment, like rainwater, river water, and sewage water. Aside from that, self cleaning filters are also used in irrigation systems, cooling systems, power plants, steel manufacturing, fountains, and the pulp and paper industry.
Industrial filters are usually more durable, and come at a higher price point than those for domestic use.
Choosing the Right Self Cleaning Filter
The most effective way to choose a self cleaning filter is to match the filter with the requirements you have. Because each self cleaning filter has specific applications, the amount of solids and sediment in your water can be used as a starting point to choose a suitable self cleaning filter.
The most important thing to consider when choosing the right self cleaning filter is the purpose. After that, ask yourself about the water quality and what is the most harmful contaminant in the water that you want to expel. Let’s look at these factors and what filter you can use.
Water containing hard solids – For water containing hard solids, you can use a screen filter for large particles of hard solids, while an additional cartridge filter should be used after a screen filter if you have finer hard solids, like fine silt.
Water with low amounts of solids – For water with a very low concentration of solids (whether hard or soft), such as mains water, well and spring water, and swimming pools, you can benefit from y-strainers, cartridge filters, sand filters and other media filters. For example, sand filters are usually used in swimming pools. Rainwater tank filters also fall into this category.
Water containing some solids – For water with a low to medium concentration of solids (whether hard or soft), such as river water, farm pond water, lake water, or seawater, you can use y-strainers, cartridge filters, self cleaning filters, sand filters and other media filters, self cleaning screen filters, or hydro cyclones. In particular, hydro cyclones are used for heavier solids, while sand and other media filters are best suited for soft solids.
Water with noticeable solid concentration – For water with a medium to heavy concentration of solids, such as livestock unit wastewater, vegetable washing and food processing units, laundries, and mines, you can look into run down/parabolic screens, filter pumps, and hydro cyclones. Industrial filters tend to be more heavy-duty.
Water with heavy solid concentration – For water with a heavy concentration of solids, such as agricultural slurry and sewage sludge, you have to use slurry separators, centrifuges, or filter presses. You’ll also want to use a sludge or slurry pump for these applications.
There are many companies that specialise in filters. So, if you’re unsure, you can speak to an irrigation supplier for advice. Remember that the goal of filters is to make your water treatment process efficient and cost-effective, so picking the right one for your purpose and water condition is crucial.
Installing a Self Cleaning Filter
To install a self cleaning filter, you’ll need to follow the instructions provided for that filter, or contact a local irrigation technician. If you are installing a self cleaning filter yourself, following these simple tips can help make the process much easier:
1. Keep maintenance in mind – At times you will have to perform routine maintenance on your filter, and the irrigation system in general. It’s important to not only install inlet and outlet valves for easy access, but making sure the system is installed in an accessible area
2. Install the correct filter – When you install a self cleaning filter, there will be a lot to choose from, and it can be difficult if you plan to install it yourself. Make sure you check the downstream pressure of your irrigation system as well as the flow rate so you can choose a filter that is compatible and will work effectively.
3. Have a safety plan – As part of your irrigation system, it’s important to have a back up plan in mind. By installing a manual override pressure gauge level, you will have an additional layer of protection if you need to troubleshoot an issue.
4. Don’t forget a relief system – Relief valves are an excellent safety precaution for your irrigation system. Choosing to install pressure relief valves gives you an additional layer of security when it comes to potentially hazardous pressure build ups.
Related Questions
Do I Need a Screen Filter for Drip Irrigation?
Screen filters are highly recommended for use with drip irrigation systems. A screen filter is an affordable and simple way to improve the quality of water used in your drip irrigation system, by adding a fine layer of water filtration.
The screen filter used in a drip irrigation system will excel in catching any debris or contaminants in the water. This will help your drip irrigation system provide cleaner water to your plants, and help improve growth.
Why Do We Need to Backwash Filters?
Backwashing filters is necessary because it’s the most efficient way to clean the filters you use in your irrigation system. Over time your filters will get clogged with debris and dirt it catches and filters out of your water. Backwashing is a way to clean those filters without needing to replace them.
Disclaimer:
This article is published for general informational purposes only and does not constitute professional advice. Any action you take upon the information you find on this website is strictly at your own risk. Always ensure you have the right qualifications and certifications to carry out DIY work and never put your safety at risk. Hills Irrigation recommends consulting a professional for all electrical and plumbing work.
Vince is Managing Director of Hills Irrigation and is supported by Lisa in an administrative capacity. Andrew, Isaac and Megan look after the day to day needs of both online and shop customers. As Project Manager, Vince is also responsible for installation projects along with his team. It is his responsibility to work closely with clients to ensure that scope of work is understood and followed.
