Knoll Maschinenbau GmbG

Archiv for: Adhesive

Processing adhesives with the MX vacuum pump

A well-known Swiss adhesives manufacturer is an important supplier to the international automobile industry of glues for bonding car bodies, windscreens and dashboard kits. Air trapped in the adhesive would allow gaps in the sealing contours, which in turn would result in leakage inside the vehicle due for example to the ingress of rainwater through the windscreen. The adhesive must therefore be absolutely free of trapped air in order to ensure a continuously tight adhesive bead. For this reason, the adhesive is manufactured under vacuum and delivered to automobile manufacturers in vacuum-sealed drums.

For this application, an MX50R-80/20 with an electric heating jacket and dry run protection was placed below a vacuum mixer. The MX is used as a mixer discharge pump and fills the drums with adhesive under vacuum. A vacuum of 20 mbar absolute is maintained in the mixer. In this process, the filling time of the moisture-reactive adhesive including 800 µ filtration is about 4 minutes per drum.

The feed housing and the conveyor worm of the progressing cavity pump MX from KNOLL have a special nanotechnology-based non-stick coating to avoid unwanted bonding effects and bridging. Due to the highly abrasive properties of the medium and high viscosity values ranging from 700,000 – 1,500,000 m Pas, a solid stator made of a specially hardened material is used for this pump. The KNOLL solid stator uses the tried and tested “half-shell system” employed in the production process for the KNOLL screw spindle pumps type KTS.progressing cavity pump with solid stator

The pump was tested for vacuum tightness for a week prior to delivery, and it was found that the high vacuum level remained absolutely constant. 

In this specific application, our competitors’ pumps achieved a maximum life of only approx. 3 months and showed the first signs of wear after only a few weeks. The MX by KNOLL Maschinenbau GmbH has already been in use for more than 16 months and so far has not shown any signs of wear.