Model HGF Gravity Filter
The Filtertech Model HGF Deep Bed Gravity Filter provides effective clarification for a variety of applications. This is accomplished by using our patented labyrinth side seal design, which provides an efficient seal along each edge of the filter media. This eliminates the migration of solids around the edge which is a common problem with “wheel” type cylindrical bed filters. The deep liquid pool creates a high pressure differential across the media allowing higher filtration rates and lower filter media consumption.
Mode of Operation
The dirty liquid to be clarified is either pumped or flows by gravity in to the top inlet of the filter. The liquid passes through the low velocity inlet distribution header where it is discharged in to the bed of the filter.
A layer of disposable filter media is positioned within the filter and is supported by a flat wire conveyor belt. As the dirty liquid passes through the filter, solids are removed by the disposable filter media allowing only the clean liquid to pass through, which drains out of the bottom of the filter by gravity.
Solids accumulate on the surface of the media to form a filter “cake” which further improves filtrate clarity through depth filtration. The inlet header is submerged in the liquid pool to minimize disturbance of the filter “cake” and foaming of the liquid. The filter also includes Filtertech's patented labyrinth type positive side seal design which creates a double side seal to prevent migration of solids around the edge of the filter media.
Over time the filter “cake” becomes thicker and more dense such that the filtrate rate through the media decreases causing the level in the liquid pool to rise. This is sensed by a level control float which then automatically indexes the dirty media out of the filter in short increments while also introducing fresh media into the filter. The liquid level drops whereby indexing is stopped, thus providing for completely automatic operation.