Food & Beverage

The goal of filtration at bottling is typically to remove the risk of microbial contamination which can lead to shelf life issues. This is typically accomplished by using a 0.45 or 0.65 micron membrane that is rated for microbial removal. Note that not all membrane filters will have microbial claims. The membrane filter is generally protected by a high efficiency 1 micron prefilter.

It may be possible to clean and reuse many filters depending upon what plugged the filter and how plugged the filter is. The contaminant must be able to be removed either chemically or mechanically. This is more likely when the filter is not highly plugged. If the filter is planned to be reused, it is best to operate the filter until it is no more than 3 - 5X the clean differential pressure.

The cleaning method for the filter will depend upon the contaminant and the filter type. Chemicals used must be compatible with the filter and yet effective at removing or dissolving the contaminant. Recommendations are published in Technical Bulletin TB-008.

The key to optimizing any filtration system is to get the right balance between economy and performance. This balance is determined by a number of factors such as particle characteristics that include the nature of the particle and the volume of particles; fluid characteristics such as viscosity and temperature; and cartridge characteristics such as filter pore rating, efficiency and dirt holding capacity or throughput. There are several steps in determining the best recommendation: Minimum Core Requirement can be used as a baseline value to determine the minimum number of filters required to meet the flow demand; Flow per Ten Inch Equivalent (TIE) is the idealized maximum flow rate per ten inch cartridge based upon the type of filter being used in the application; Filter Flow Rate should be considered when the correct filter media (micron rating, membrane, pleated or depth) has been identified using the actual published filter flow rate data in Data sheets; Actual Testing conducted at a small scale yields the best values.

To protect the liquid contents from microbial or particulate contaminant, it is customary to install a vent filter on the tank. When liquid is added or removed from a tank, air must move in or out of the tank to fill the changing airspace above the liquid. A tank vent filter allows air to flow in both directions and prevents possible damage to the tank that could result if air is compressed during tank filling or a vacuum is created during tank emptying. Since liquid can "plug" the pores of a hydrophilic cartridge, it is critical that a hydrophobic membrane such as TefTEC which uses a PTFE membrane.

Plant extracts often yield high levels of solids, some of which may be deformable as well as oils, both of which complicate filtration. Filtration is best accomplished using pleated multi-layered depth media such as QXL or glass media where oils or hazes formation may be an issue.

Post fermentation removal of sediment and yeast is typically done using high solids removal technology such as lenticulars, filter press or even microfiltration crossflow. Any remaining sediment and yeast can effectively be removed in the filtration step prior to the bottling process. In types of beer, haze often caused by protein complexes can develop and these can be addressed using a charged media such as glass.

It may be possible to clean and reuse many filters depending upon what plugged the filter and how plugged the filter is. The contaminant must be able to be removed either chemically or mechanically. This is more likely when the filter is not highly plugged. If the filter is planned to be reused, it is best to operate the filter until it is no more than 3 - 5X the clean differential pressure.

Post fermentation removal of sediment and yeast is typically done using high solids removal technology such as lenticulars, filter press or even microfiltration crossflow. Any remaining sediment and yeast can effectively be removed in the filtration step prior to the bottling process