Flexible woven metal filter media with 3D-structure

Woven Filter Media

For liquid filtration at high temperatures the material of choice is often sintered metal powder (PM) type filter. Tubular elements are available in a range of alloys and with pore sizes below 1 micron. The operational life of the media can easily extend over years, and its low maintenance is a strong argument for adoption. At least, in theory…

In practice it is often another story. While there are cases where PM works as promised, there are instances where the results disappoint. To understand the reasons for this, we need to take a closer look at the design of such a sintered PM element:

The element wall is built of narrow sized stainless steel powder, which is sintered at high temperatures to form a rigid, but porous structure. Since the pore size is determined by the size of the sintered particles, the finer the particles, the smaller the resulting pore size.

In solid/liquid separation, typically a fraction of those particles finer than the pore size of the filtering media pass through, the largest particles are held back in the filter cake on top of the media and some get stuck within the PM structure. It is this last solids fraction, which normally cause trouble, because the rigid porous layer prevents any movement and back-flushing does not always remove those particles. Over time trapped solids accumulate and begin clogging the porous metal. Ultimately, the PM elements need to be either chemically treated to dissolve the entrapped solids, heated to a high temperature to burn off the impurities, or they have to be replaced altogether.

As an alternative to traditional sintered PM elements, and specifically to address operational deficiencies, DrM has recently developed a new type of filter media built on a 3D-woven structure made of stainless steel microfiber. This media has a significantly higher open area for flow than PM, but is still capable of retaining particles down to the 1 micron range. Another key feature is that the woven structure flexes outward during back-flushing. This expansion movement releases trapped particles, thus preventing solids build up and eventual clogging. In addition, the media is rated for temperatures well above 300ºC and both slurry and dry cake discharge is possible.

In short, the woven stainless steel microfiber elements significantly extend the application range of our filtration products without sacrificing any of the process options the well-established FUNDABAC filter provides.

Selecting this media makes sense for applications with high temperatures (above 200ºC) and where the feed solids have a tendency to clog. Target markets are in chemical syntheses where catalysts need to be removed at high temperatures, and in refineries for the removal of FCC catalyst fines from heavy cycle gas oil.



Ever since the introduction of the FUNDABAC® Filter various kinds of clamps have been applied to securely fix the filter flexible media to the FUNDABAC® filter element. The clamps come in various forms, such as plastic wedge rings, one way clamps in stainless steel and re-usable screw clamps in stainless steel, titanium and zirconium. Clearly, as with the materials of construction for the rest of the filtration system, the choice of clamping materials is dependent upon the properties of the materials being handled in the filter and the process conditions.

FUNDABAC® Clamp-Less Candle

For applications like chlor-alkali, viscose and other processes where we employ our polypropylene (PP), polyvinylidenfluoride (PVDF) or polyphenylenesulfide (PPS) filter internals we have previously used polymeric PP, PVDF or PPS wedge rings or titanium or zirconium wire clamps. DrM are proud to announce the launch of a new design of clamp-less candles, which will be offered in PP, PVDF and PPS.
With the introduction of the clamp-less design for our plastic filter elements, separate clamps become obsolete. Here, the filter media is fixed with a special screw mechanism that is part of the filter element.

This offers a number of advantages over the previous design:

• Smooth design: No cake deposit on the clamp
• Metal free
• No difference in thermal expansion
• No corrosion attack
• Suitable for metallic and plastic registers
• Suitable for a wide range of filter media
• Filter elements can be supplied with the filter media already assembled

The clamp-less candle is now being offered as a standard part from DrM Filter Technology Pvt. Ltd., but the previous design with separate filter media clamps is also still available upon request.

Ganesh Aghav, DrM

Tianqi Lithium

Kuala Lumpur, Malaysia. DrM, Dr Mueller AG has signed a contract for the
supply of specialised filtration equipment for Tianqi Lithium Australia’s newest
lithium hydroxide processing plant, which will be located in Kwinana, Western
Tianqi Lithium, which controls a majority stake in the Greenbushes mine, the
world’s premier producer of lithium concentrate from spodumene, is building a
downstream processing plant for lithium hydroxide in Kwinana, 40 km south
of Perth. The plant will convert around 161,000 Te per year of spodumene
concentrate into 24,000 Te of lithium hydroxide, for use in the growing global
market for lithium ion batteries.


DrM has won a contract for supplying equipment that will support critical
functions in the overall process. DrM’s CONTIBAC® candle filters will be used as
main process filters on three key extraction stages and a number of DrM
CONTIBAC® SM filters will be deployed in key areas as guard filters.
Whilst the commercial aspects of the project were handled from DrM’s SEA
Sales and After-Sales Service Centre in Malaysia, the units will be
manufactured at DrM’s Asian production plant located in Shanghai and be
supplied as complete modular skid mounted filtration units.
DrM has already supplied a number of process filters to Tianqi’s lithium
processing plants in P R China and Tianqi now operate a range of DrM
CONTIBAC® candle filters (slurry discharge) and FUNDABAC® candle filters   (dry cake discharge) units
for lithium processing.
This latest contract has been awarded due to DrM supplying “the best
available technology” and the long-term experience with the economy of
operation, reliability and efficiency of the DrM systems
Scope: 5 x CONTIBAC® candle Process units, 6 CONTIBAC® SM Guard units
Customer: Tianqi Lithium, Australia
EPC: MSP, Perth

Increasing Production Yield Via the Optimization of Mixing Efficiency: Insulin Mixing Case Study

The number of people with diabetes has risen from 108 million in 1980 to 422 million in 2014. This number is predicted to double in the next 20 years according to the World Health Organization. It is not surprising that the pharmaceutical industry is currently investing billions of dollars to increase production capacity to cover this steadily increasing demand of insulin.

Synthesizing human insulin is a multi-step biochemical process that depends on basic recombinant DNA techniques. One small segment of human DNA carries the code for the protein insulin. Manufacturers manipulate the biological precursor to insulin, so that it grows inside simple bacteria cell suspension.1471587526

After extraction, insulin is crystallized and the suspension containing the crystals is transferred to a vial filling station. Proper mixing of the insulin suspension is critical to maintain a homogeneous concentration until the very end of the process at which time vials are filled.

One third of DrM FUNDAMIX® units produced are currently delivered to new insulin production facilities positioned globally. Insulin crystals are polymorphic, ranging in size from 50 – 100 microns. These crystals are subject to degradation if exposed to high shear forces. DrM FUNDAMIX®, with its low shear force, is the perfect solution to keep insulin in a homogenous suspension without degradation of its active enzyme structure.

Another major advantage of DrM FUNDAMIX® for insulin producers is low heel volume resulting from the capability of positioning the mixing plate in the very bottom of the mixing vessel. Since the mixing plate can be installed much lower than the impeller of a rotating mixer, the non-mixable residual volume of each batch is minimized and product waste is virtually nonexistent. Insulin producers can count on the FUNDAMIX® Vibromixer to maximize yields.

Selection of equipment for solids removal in natural gas extraction operations – CAPEX vs. OPEX considerations

The extraction of natural gas requires the removal of suspended solids from the feed stream. Generally, these streams can be grouped as follows:

Produced Water (PW) and dirty liquid streams resulting from pipeline pigging operations

Rich monoethylene glycol (MEG) recycle streams which contain various salts from the produced water. The injection of MEG at the well head is the most common method to prevent formation of hydrates and avoid pipeline blockage. Hydrate inhibition is specifically requested when low temperatures are involved. Increased activities in offshore and deep sea drilling, where lower temperatures and longer pipelines to shore result in a significantly increased risk of hydrate formation, also triggered demand for MEG injection systems.

Hydrocarbon condensate which carry over solids from the slug catcher may also require further treatment.

Screenshot 2016-03-10 08.57.04

The conventional FUNDABAC® filter is a sophisticated system capable of removing suspended solids down to 1 µm and smaller, is fully automatic and requires minimal operator intervention and maintenance expenditures.

The dry discharge capability of the FUNDABAC® filter allows for the disposal of a 50-70% dry cake and minimizes disposal requirements. Dangerous substances such as Hg, H2S and NORMs can be safely handled as a result of the fully enclosed design.

Filter aid can be used in situations where the process medium is difficult to filter, thus making FUNDABAC® filters suitable both for normal operation routines and for periodic, intermittent operations when solids generated by the system and their tendency to foul increase dramatically (e.g. pigging).
Screenshot 2016-03-10 09.38.47In some cases an automatic filter such as the FUNDABAC® may not be economically cost justifiable. Below a specific solid load, the OPEX of filter systems using disposable media (e.g. manual cartridge filters) may be desirable. This factor, coupled with a relative lower CAPEX, makes these systems more cost attractive.

In addition to being able to supply technically sophisticated FUNDABAC® filters, DrM also  offers its customers cartridge type filters. DrM’s extensive know-how in solid-liquid separation processes puts DrM in the unique position to propose the most cost-effective filtration solution for a given set of application operating parameters. DrM’s recommendations always take both CAPEX and OPEX into account.

DrM is committed to the continuous development of its cartridge filter design and aims to minimize operator exposure to harmful substances, often an issue when disposable elements need to be replaced. Information about DrM’s cartridge elements and unique housing design can be found below or by contacting DrM.

DrM technical sales representatives are often asked to provide a rough cost impact study that compares its cartridge filters to its fully automatic FUNDABAC® filters. It is clear that due to design specifications and materials there is a broad range of variables impacting CAPEX. By creating sets of assumptions however, we can project figures that can give a general indication of CAPEX and OPEX, as per example on the next page.

Input figures and life time cost calculations for some cases

Screenshot 2016-03-10 09.39.50

Please note that above figures do not take into consideration the disposal cost of either the solids cake discharged from a FUNDABAC® Filter or alternatively filter cartridges.

Operating costs are also not considered in the above comparative analysis. It should be assumed that both of those cost drivers will favour of the FUNDABAC® Filter due to its automation and lower solid waste production. Geographical location can influence these values significantly. Business operators will likely want to include those numbers in their own calculations.

As expected, the lifetime cost of a cartridge filter system is lower than that of a FUNDABAC® Filter in low solid loading applications (say, below 5’000 kgs/year) since the number of replacement cartridges is fairly proportional to the solid load.

Screenshot 2016-03-10 09.40.08

For higher flow and solids concentrations, the FUNDABAC® filter is more cost economical than cartridge filter systems. It should be noted that this analysis only takes CAPEX and OPEX into account. Other factors such as operator and environmental safety, proximity of disposal sites as well as physical space requirements may impact investment decisions.

Looking at past experiences in natural gas extraction plants, we can deduce that for removal of divalent salts from MEG that a FUNDABAC® Filter should be the best filter choice due to the higher solids load, despite the fact that liquid flows are not so high.

For produced water we need to view things differently. When considering both pigging and normal water treatment, a FUNDABAC® filter should be the equipment of choice. It can cope with fluctuating input solid loads and as well, higher concentrations are easily managed. For normal operation however, a cartridge filter system may be good choice.

For hydrocarbon condensate we normally deal with a low solid load and high liquid flows. The final consideration will therefore depend on the detail input data. Here the tendency is towards cartridge filters. However, the operator may also want to consider operator exposure to toxic chemicals and their disposal cost.


As can be seen in the above analysis, filter type selection is not as clear cut as it may first seem. To get a better understanding, input values can be applied to run a cost simulation model which will help in the decision making process. In this regard, DrM can provide valuable input.

FUNDAMIX® Gas Injection

FUNDAMIX® Trial with size FM2 with Gasinjection through the shaft at different flows and amplitudes
With the injection through the shaft (which is not possible with a rotating stirrer) a better dispersion can be reached and the solution is much cheaper as a sparger ring. Also better suitable for CIP/SIP.