Pressure Leaf Filters
For more than a century, pressure leaf filters have provided an economic, reliable and proven cake filtration solution for liquids with higher solid loads, between 0.01% – 3%. These highly effective systems consist of pressure vessels containing individual ‘filter leaves’ supported on a manifold.
Liquid is pumped into the pressure leaf filter vessel where it is pushed through the filter leaves, exiting the vessel via the manifold. Solids are retained and form a filter cake on the leaves. When filtration is complete, the filter is drained, leaving the cake on the filter leaves. Depending on the application, the cake can then be sluiced off the leaves or dried and then discharged by a pneumatic vibrator.
Vertical pressure leaf filter
This vertical pressure leaf filter is equipped with vertical, rectangular filter leaves. The filter leaves are mounted vertically and connected to a filtrate manifold at the bottom of the filter tank. For dry cake discharge, a vibrator is used to remove the cake from the filter leaves when the filtration process is complete.
Horizontal pressure leaf filter
Horizontal pressure leaf filters contain filter leaves positioned vertically in a horizontal filter tank. These filters can have a large filtration area and enable visual cake inspection after every cake discharge. An optional vibrator installation can be installed for cake discharge.
Premature screen failure
One of the most common problems that operators face with their vibrating separator is premature screen failure. Vibratory separator screens are considered a wear item in that they’ll eventually wear out and need replacing. Unfortunately, a screen’s life is dependent upon many variables, such as the material type it comes into contact with, any environmental extremes, cleaning methods used with it, etc., so it’s not easy to say how long a separator screen should last without taking those factors into consideration. However, you should get plenty of use out of your screen before needing to replace it.
Delamination. There are many possible causes for premature screen failure. If a screen is delaminating or separating into layers on the tension ring, this could indicate a temperature issue. Every screen manufacturers’ temperature limits differ for epoxy-mounted screens. Some limits are as low as 120oF (49oC) while others are as high as 200oF (93oC). If the material temperature exceeds the screen’s limit, the epoxy will begin to weaken and fail, causing the screen to delaminate. The pH level of the materials being processed also needs to be taken into account, as it affects the screen. Materials with a high pH level of 10 or more tend to decrease the epoxy’s temperature resistance, causing a screen to delaminate even at temperatures within the manufacturer’s given limits. If you think you might encounter this problem because your process requires separating materials at a high temperature greater than the screen manufacturer’s limits, consider using a welded screen if possible. A welded screen can withstand temperatures up to 400oF (204oC). This screen type isn’t always an option for food and other sanitary applications, so be sure to speak with the screen manufacturer to find out about other options; however, these same issues can occur with differing screen types.