Variable Pore Micro Filtering

The VPMF introduces the Perfect Backwash Micro Filter, a unique Variable Pore-structure Micro Filter (VPMF), with a wide variety of applications and uses offering cost effective and reliable filtering from 0.2 μ to 25 μ.

Even though there are various technologies used for separating contaminant from polluted water, one of the simplest methods is filtering. Filtering has been identified as one of the best separation technologies because it prevents secondary contamination and does not simply convert the pollutants into other chemical characteristics or residue.

Most previous filtration technologies consisted of conventional and traditional sand filters, spun-bonded or melt-blown cartridge filters, highly polymerized compound, ceramic and membrane filters, and metal filters. Those products have been made of various kinds of raw materials and pore sizes from several tens of micron to ion size. Although those technologies were capable of filtering well, they were unable to be used at the wider application ranges pertinent to the industrial field. Applications have often been limited to purification plants and other very simple treatment applications. The limitation was essentially the result of poor performance in backwashing due to the fixed pore structure — it was very difficult to re-penetrate the fouled pore structure in anything other than ideal conditions.


The VPMF (Variable Pore-structure Micro Filter) forms a temporary filter structure by compressing the laminated micro fibre layers according to water flow, and then, by backwashing, dissolves the laminated layers of the filter structure. In other words, the VPMF conducts a depth filtering against laminated micro layers, and then easily separates the pollutants gathered between the micro fibres during the dissolution of the layers using both water and air pressure. The combined water and air pressure also provides a vigorous shaking of the fibre layers for total contaminant cleaning.



The Perfect Backwash

A flexible micro fibre is cut at equal length and then remodeled into a cylindrical shape, attaching the micro fibre to the holders of each end and connecting them to the lower flange of the pressure vessel. The filter holder attached to a non-fixed side can be freely movable within the pressure vessel in the vertical direction according to water flow.

Filter Cycle

The inflow of raw water gradually compresses the cylindrical filter media. When the filter pressure reaches critical (or optimum) depth, no further filter pressure will occur and the raw water will be filtered for discharge.

Backwash Cycle

During backwash, water and air are forced through the effluent end of the filter and the compressed filter is gradually expanded in an upward direction. The pore structure divides into strings and the fine air bubbles separate the pollutants discharging them to the raw water outlet. The cylindrical filter media vibrates vigorously resulting in a synergism of washing and thus conducts full backwashing.

Operating Mode

A pump supplies raw water to the filter thereby compressing the media. Until full compression is attained, water flows back to the raw water supply. During backwashing, water is pumped from the backwash water tank back through the filter. The media relaxes releasing contaminant to an outlet. At the end of the 3-5 minute backwash cycle, air and water are both injected creating a strong vibration.

Simple, Automated Control

The VPMF filter offers a simple method to filter contaminated water down to 0.2 micron. The five different models range from 0.2 micron up to 25 micron thus providing a wide range of applicability for treated water, wastewater and sewage including numerous industrial applications. The system is fully automated and can be controlled by either a timer or pressure to initiate backwashing.

Depending on the application, the filtering cycle will range from approximately 1–1.5 hours with backwashing requiring from 3-5 minutes. This short backwash cycle provides excellent throughput. The system is readily expandable by simply adding more modules. The small size of the modules means a small footprint. When used in conjunction with other stages of treatment, the VPMF can reduce the overall footprint of a facility while delivering high quality effluent. The VPMF can be a reliable, low cost method of attaining the required effluent quality.



A self-contained and fully operational pilot unit is now available for demonstration and evaluation in order to establish the operating parameters of a full-scale plant. This unit can be put into the field for onsite testing and evaluation purposes. For more info and to discuss a demonstration, contact Gurney Environmental.