A device installed as part of a water system through which water flows for the purpose of removing turbidity, taste, color, iron, or odour.
Filters can be loose media beds in vessels or cartridge -type devices and filter media can be used for mechanical, adsorptive, neutralising or catalyst / oxidation filtration processes.
Filter and water softening systems typically utilises a control valve as previously covered. These control valves are mounted onto pressure tanks generally referred to as Vessels. These have a threaded “neck” with a squared shoulder to receive the control valve to provide a seal.
A vessel is designed to contain the pressure of the water system and typically consist of a PTFE liner which is then wrapped in a coating of GRP to ensure rigidity and the ability for ” cycling” which refers to the raising and lowering of pressure which occurs many times each day.
Regeneration is the term given to the process of renewing or rejuvenating the media. Any system for water treatment will have an optimum capacity whereby it will perform to it’s best, but beyond which the performance falls away.
This is true of water softeners as well as filter systems. This is referred to as the capacity of the unit. Once a water softener or an automatic filter unit reaches it’s capacity it is necessary to regenerate so as to renew it’s ability to perform it’s function. In the case of a water softener this involves the use of Brine made up of water and salt.
This regenerant is used to displace the contaminant ions deposited on the ion exchange resin during the service period. These contaminants are washed away to drain and replaced with sodium ions ready to return to service. Water softening resins are designed to exceed 900 regenerations.
This means that if a water softener regenerates 3 times per week then you can expect beyond six years resin life. This is a minimum, so if the softener only regenerates twice per week you can see that the life of the resin should exceed ten years.
After the regeneration the control valve goes into Service position:This is the normal position for a control valve. It means that the raw water is entering the control valve and passing through the media bed, being treated and going to service as demanded.
In the case of larger water softeners you would typically have a vessel with a control valve mounted on top. Beside this you would have a salt bin.
These allow for the storage of two or more bags of salt in the salt bin, so the brine tank only requires filling less often.
Salt consumption: The rule of thumb is that the larger the softener is, the more salt efficient it is. This also applies to water consumption.
A large water softener, of 20 – 25 litres volume of resin will only require to regenerate maybe every 7,10 or 14 days. Because of the height of these units the brine is being drawn through a taller column of resin.
This means that the brine is utilised to it’s maximum efficiency and marginally less salt is used in comparison to a cabinet softener with a shorter column of resin. The same can be said of the water used.