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Seam sealing technology – patent registration


Our patent application has been officially approved and published. The patent application was filed in 2015 after several months of hard work, and after conducting many researches and experiments, which finally confirmed the innovation and effectiveness of the filter bag seam sealing method.

The patent relates to the method of sealing the filter bag and the filter bag itself with seams sealed according to this method. The purpose of conducting development work in this area was to provide our customers with a product that meets the most stringent dust emission standards and to set a trend in the application of technologies to reduce dust emissions into the atmosphere on a global scale. Moreover, our invention makes it easier for industrial plants to adjust their environmental protection installations to the requirements of BAT (Best Available Techniques) conclusions.


The patented method of sealing filter bag seams involves injecting a liquid sealant into the seam center (between the material layers) immediately before the sewing process. The administration of the sealant and the sewing of the material are only a few milliseconds apart. During the sewing process, when the needles pass through the material, the sealant is automatically filled into the sewing holes and material edges (sealing). Immediately after sewing, the process of hardening of the liquid sealant to the final solid form with high elasticity, which is crucial due to the performance characteristics of the filter bag, begins.

Advantages of our solution

The sealing agent used is resistant to very high temperatures (over 300 degrees Celsius), to the aggressive chemical environment found in the filtering equipment and, most importantly, it is neutral, which means it will not lead to a chemical reaction or contaminate the customer’s product. In addition, we offer filter bags sealed with a special version of sealant approved for food contact.

The seam sealing method itself has many benefits and advantages over other sealing solutions available on the market. First of all, there are no restrictions on its use with different filter materials, such as needle felts and fabrics, which means that a filter bag made of any material (filter medium) can be sealed with this method. Moreover, seam sealing with our method is highly resistant to falling off, delamination, mechanical damage during installation and abrasion from the outside.

For economic reasons, it is important that the application of seam sealing by our method takes place on-line during the sewing process, e.g. on an automatic sewing line for filter bags, and what is most important, it is done at full production speed. The above means that a separate technological process is not needed for sealing and the fact of using RKDTD Seam Sealing does not require slowing down the production line, which allows for significant savings in production costs.

Research confirms the uniqueness of the technology

TThe effectiveness and durability of the RKDTD Seam Sealing method has been proven in many studies and experiments.

During the invention process, it was necessary to test the sealing strength to ensure that filter bags sealed with the RKDTD Seam Sealing method can operate in the filtration equipment for many years and be exposed to adverse physical conditions such as high temperature. This test was conducted in a professional aging device simulating the operation of a sealed filter bag at high temperature for many years. The results of the sample analysis after the test showed the presence of the sealant inside the seam, the correct sealing of the needle holes and the maintenance of high elasticity of the sealant.

Finally, it was time for the combat test of filter bags sealed with the RKDTD Seam Sealing method, which we conducted in cooperation with the Poznan University of Life Sciences, which supported us from the beginning in the research work. Several samples of filter bags with and without seams sealed according to the RKDTD Seam Sealing method were installed in a test filtration unit. The results from the sealed filter bags showed an average 37% reduction in dust emissions compared to the unsealed filter bags. With proof of the effectiveness of our solution, we continued to research and improve the product. 

The final proof of the effectiveness of RKDTD Seam Sealing was demonstrated by a test on a filter material tester according to VDI 3926. A sample of material with a longitudinal seam with and without sealing was tested, Pural NF test dust and conditions simulating normal filter bag operation (temperature, pressure, cleaning, etc.) were applied. Comparative results from the measurements showed a more than 97% reduction in dust emissions when using the seam with sealing according to the RKDTD Seam Sealing method.


Hundreds of thousands of RKDTD Seam Sealed filter bags have been delivered over the years to more than 100 metallurgical plants, lime kilns, waste incineration plants, power plants, cement plants, food processing industries, enabling atmospheric dust emissions to be well below 1 mg/Nm3.

Our products with RKDTD Seam Sealing are used primarily in waste incineration plants, power and heating plants, metallurgical plants, and in any other industry that is required by law or other restrictions to keep dust emissions to the atmosphere as low as possible.


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