Bünder & Schmitt, of Zülpich, has more than 45 years' experience in the mechanical engineering and packaging machine sector; this experience is reflected in a product line that includes a wide variety of filling and sealing systems. The field of possible applications is large, for there are many liquids and pastes that must be filled in ampules, tubes, bottles, and canisters. Accordingly, many well-known manufacturers in the food, cosmetics, pharmaceutical, and chemical industries are among Bünder & Schmitt's customers. Director Felix Konsek explains: "There are many different requirements for a filling system, so that we usually adjust our machines for the task in question in close cooperation with the customer.
In order to be able to guarantee quality, reliability, and efficiency all the time with all flexibility, this owner-managed company relies on many machines produced in-house and on proven suppliers. Thus at Bünder & Schmitt, in approximately 80% of all filling systems, there are progressing cavity pumps from KNOLL Maschinenbau, Bad Saulgau.
Progressing cavity pumps – frequently also called Mohno or Mono pumps after the original licensee – are among the rotating displacement pumps. They work gently and with low pulsation, thus offering a solution for conveying and dosing a wide variety of media.
Since 2007, KNOLL has provided this system manufacturer in North Rhine-Westphalia with the MX progressing cavity pump. "A trusting partnership has developed,: reports Felix Konsek. "With the MX pump, KNOLL offers not only an outstanding price/performance ratio, it also provides the pump in all of the variants we require." In the end, the pumps used for filling must not only be designed for the respective use case, their design with respect to the materials used also depends on the media to be conveyed.
Felix Konsek provides an example: "For the food and pharmaceutical sectors, we absolutely require hygiene pumps with the appropriate approvals. For the filling of acids, by contrast, the pumps have to be acid-resistant. For this too we have worked with KNOLL to formulate special solutions, ones that have particular coatings."
The KNOLL MX progressing cavity pumps are designed in modular fashion throughout and constructed so that they can fulfill nearly all of Bünder & Schmitt's requests. Thanks to the version with EvenWall® technology (see text box), they have great pressure stability, low backflow, and good intake behavior.
These progressing cavity pumps are – from the small MX 10 to the MX 50 – available in many standard models. For the popular MX 20, for example, there are nine pump sizes, which enable customers to adjust the delivery rate or delivery pressure according to their needs.
And not just the pump set can be changed from the toolbox. There are also various types of housings available: suction housings for thin liquid products or hopper housings for viscous liquids such as doughs. In addition to standard housings, KNOLL also makes available special models, for example with double jacket for heating or cooling the medium.
The KNOLL MX progressing cavity pump also consistently fulfills all hygiene requirements of the food industry. CIP and SIP cleaning are possible. This means the pump is constructed with little dead space and so that it can be cleaned where it is used without dismounting. All metal parts that touch the product are made of stainless steel. This material and the high-quality elastomer, which is certified across the boards for the hygiene sector, ensure resistance to corrosion, high temperatures, and chemicals. Both the pump housing and pressure connections are also essentially electropolished. This way, the KNOLL MX pump can fulfill the guidelines according to EHEDG and 3A.
The KNOLL MX progressing cavity pump provides Bünder & Schmitt with ideal prerequisites. Felix Konsek also attests to its outstanding quality: "We have had very good experiences for many years with the all-stainless steel MX variants that we have used. They are outstandingly made and we have had no problem even with the axial face seals, which were problematic from earlier suppliers."
Even in new developments like the MFR023 carousel-type machine presented in 2014, Bünder & Schmitt relies on KNOLL products. This filling system includes twelve MX progressing cavity pumps, which can fill more than 200 half-liter containers in a minute. Felix Konsek notes the unique nature of the system: "For such carousel-type systems, other suppliers use pump types such as piston dosers. We are the first and thus far the only one to offer such a system with progressing cavity pumps." The development was quite definitely a technical challenge since the pumps and their drives must turn too. However, the progressing cavity pump offers the user essential advantages. Thus, for example, he can regulate the delivery rate during filling and even work in reverse. For Felix Konsek this is a clear customer advantage: "We provide a high-performance system with fewer filling points and a smaller space requirement."
Bünder & Schmitt GmbH
Bergheimer Straße 9
Tel.: +49 (0)2252 / 835269-0
Fax: +49 (0)2252 / 835269-20
A special constructive feature of the KNOLL progressing cavity pumps is their design in EvenWall® technology. This means that the stator sheathing is adapted to the inner contour of the stator and it has an elastomer layer with an even wall thickness.
This provides numerous benefits as compared to conventional designs that feature a cylindrical exterior geometry of the stator sheathing and accordingly varied wall thicknesses of the elastomer. This includes much greater pressure stability, less backflow, longer durability, better efficiency, less shearing of the product, and better suction behavior. In addition, with a closed (single-stage) chamber, the MX pump provides pressure of up to 10 bar, while conventional progressing cavity pumps are limited to 4 to 6 bar. Thanks to its multi-stage construction, the MX progressing cavity pump achieves pressures of up to 80 bar.