For rapid sand filters to function well, it is critical that you clean the filter media regularly. You also need to backwash the gravity filters like those supplied by www.ashtuck.com to remove the accumulated particulates from the drain. Moreover, a combination of water and air or an upward flow of water is essential to scour all the media in the filters.
Because of all these requirements, manufacturers developed parallel-lateral filter underdrains to efficiently distribute air and backwash water. In this recent upgrade, plastic plates replace the previous gravel layers.
Understanding a Filter Underdrain’s Function
The three primary components of all rapid gravity filters are the filter underdrain, media, and gravel layers; the former supports the latter two. During the backwashing process, the filter underdrain distributes the backwash water evenly through the filter. The filter’s efficiency depends on how well the backwash cycle is conducted.
Developments in Filter Design
Initially, dual parallel filter underdrains consisted of two secondary laterals and a single primary lateral. The latest underdrain design, which is known as a low-profile block, is a single block that comes in two channels, with the lower profile for allowing greater media depth and shallower filters. The lateral area was also enlarged for proper distribution in longer lengths.
This new filter block design requires less grout between rows, and its installation takes a shorter time. Due to its versatility, you can integrate the dual lateral underdrain block into your new installation, or as a retrofit. The dual parallel lateral filter underdrain is a unique type of a modular block that offers a more compact filter design for greater operator safety, and efficient distribution of media and water to enhance the output of the filtration process.