Across many industries, operators and managers of equipment have learned the undeniable value of preventative maintenance as part of any maintenance and operation strategy. It enables you to take the necessary actions to prevent breakdowns, equipment failures and accidents. As a result, benefits include lower maintenance cost, reduced equipment replacement costs, fewer interruptions to critical operations, improved equipment longevity and increased efficiency.
The precise application of water and nutrients through precision irrigation systems has many benefits. These benefits are however lost if systems are not installed, operated, and maintained with the necessary expertise. Maintenance of the entire system is crucial, but this article looks at filter maintenance specifically.
Lack of regular preventative filter maintenance and optimal operation will lead to inefficient filter operation and even breakdowns. Keep in mind that wear and tear always increase exponentially.
These problems will ultimately compromise the filter and as an effect the entire irrigation system, it can lead to yield losses. In the field, Team Netafim, often notice that filter maintenance is neglected or done incorrectly. In many cases, problems could have been avoided if maintenance had been done preventatively, timeously, and correctly.
Maintenance can be divided into three sections:
- Weekly maintenance.
- Maintenance at the end of the irrigation season.
- Maintenance at the start of the irrigation season.
Be it weekly or seasonal activities, it is important that the entire team is trained on the necessary actions and a strict routine is formed to ensure that all planned maintenance activities are done.
Visual inspection and testing of components is an integral part of preventative maintenance, be it inspecting filter rings or checking the pressure differential between the filter inlet and outlet. This ensures that possible problems are identified and corrected before they have a significant impact on the efficiency and longevity of the entire irrigation system.
Let’s have a look at maintenance activities for screen and disc filters.
Screen filter maintenance
It is important to conduct weekly visual inspections on automatic, semi-automatic and manual screen filters. The main purpose of these inspections is to check for leaks, which should be repaired as soon as possible.
If you are working with an automatic screen filter and you have found no leaks, activate a manual flushing cycle to ensure the filter is flushing successfully. The next step is to check the pressure differential. If this value is abnormally high, perform two more manual flushing cycles. If the value remains high after three manual flushing cycles, the filter should be opened, checked for failed parts and the screen cleaned manually if necessary.
Be sure to follow the manufacturer’s step-by-step guide and all safety instructions when opening the filter and taking out the screen. To clean the removed screen, use pressurised water to remove the remaining dirt. Reinstall the clean screen according to the supplier guidelines and follow all safety instructions.
In a semi-automatic screen filter, the cleaning operation must be initiated before the pressure differential reaches 0,5 bar. Some semi-automatic screen filters have an automatic clogging indicator that will communicate when the pressure differential limit is reached.
To initiate the cleaning operation, open the drain valve and turn the handle all the way out and then back in. The screen’s inside will be cleaned as you turn the handle and suction is created in the nozzles. If you are working with poor water quality or low pressure, it is advisable to perform the cleaning operation while the downstream valve is closed. Close the drain valve after the process has been completed.
If the pressure differential remains abnormally high after three completed cleaning operations, the filter should be opened, checked for failed parts and the screen cleaned manually if necessary.
In a manual screen filter a high-pressure differential will always require opening the filter for manual cleaning. Start by closing the water supply to the filter and opening the drain valve to release all the pressure. Open the filter body clamp and remove the filter cover. Carefully pull out the screen element and clean it using pressurised water. If necessary, use a soft nylon brush for more efficient cleaning. Never use any abrasive tools and make sure the body and screen O-rings are lubricated before reassembly.
Disc filter maintenance
The filter should regularly undergo a general inspection. It should also be inspected before any scheduled maintenance procedures are carried out.
Check the pressure differential between the filter inlet and outlet. Then initiate a flushing cycle and recheck the pressure differential a minute after the flushing cycle has been completed. If the pressure differential is still abnormally high, you will need to open the filter and remove the discs for manual cleaning. Before removing the filter cover, close the water supply to the filter and open the drain valve to release all the pressure.
Visually inspect the discs after they have been removed. If there is visible sediment, clean the discs according to the supplier recommendations. Furthermore, visually inspect the spine and make sure the cone membrane is not damaged. If any filter parts are damaged, replace them immediately.
When reassembling the spine and discs, make sure the number of discs is correct, as indicated by the line on the spine, and lubricate the O-rings. Also, open the command filter and clean its discs.
Choose the best and look after it
Various factors determine the success of an irrigation system, of which filter selection and setup is but one aspect. To ensure that a filtration system keeps functioning effectively and has a long lifetime, two factors should never be neglected: the use of quality products and system maintenance. In terms of product quality, the message is clear: You cannot afford to risk the financial viability of your project by not investing in the best possible irrigation equipment.
With regard to maintenance, be sure to take the right actions at the right time to ensure efficiency is maintained and filters perform at their full potential.