Menu

A perfect O-ring for perfect coffee

The customers of Angst+Pfister are superbly equipped for the international market with PERTEC® UP VMQ – the compound unites outstanding product performance with all the major approval requirements for the drinking water and food sector on all continents. For Digmesa, manufacturer of precision flow sensors, use of microtalced PERTEC® O-rings along with custom packing has resulted in significantly lower rejection rates during production.
 


May  I  take  your  order?  A coffee,  espresso,  ristretto, an Americano or perhaps the latte after  all?  Taste  may vary  from  person  to  person  –  but quantity  is never a matter  for  discussion! The precision flow sensors made by  the  Swiss  company  Digmesa  control  the  right quantity in the coffee machines of the top coffee outlets. They channel  an  exact  amount of liquid into your favourite caffeine drink. And Angst+Pfister supplies the perfect O-ring to keep the flow sensors tightly sealed. Ten million components  annually  this is the figure covering a range of sectors and customers – demonstrate on a dailybasis that the innovative, high performance elastomer compounds  made  by  Angst+Pfister  handle  extremes and keep on going and going and going...  

 

A unification of numerous properties

Angst+Pfister developed the PERTEC® product portfolio specifically for such  applications:  O-rings, mould parts, membranes, currently available  in 5 different high performance elastomer compounds for a range of industries and applications. The PERTEC® UP VMQ  O-rings for Digmesa not only provide a tight sealfor longer, they also uniquely combine the properties of durability  and  maximum  purity, for applications in the food and drink sector, with production and mechanical improvements: “Circularity and evenness are critical for these rings,” explains Reto Müller, sealing technology product leader at Angst+Pfister. In other words, the products have to be perfectly round and lie absolutely flat on a surface. “That’s a real challenge for O-rings with  a small cross section diameter and relatively large internal diameter.”
 


To the customer on air cushions

The rings are built into the flow  sensors  at  Digmesa (see  illustration). During  the automated assembly process, they must not fall into the multipart housing – which is why absolute circularity is required along with prevention of  distortion. And when  the  housing  is  being  connected,  the  rings have not to stick, even  under  the  minimal force applied – hence the importance of the friction value of the seal. Packed and stacked in boxes in their thousands  –  the weight of the rings alone make maintaining circularity, smoothness and the surface characteristics difficult after delivery to the customer. “We consequently designed a special bag with air cushions for transportation,” remarks Yves Riedo, sealing technology senior engineer at Angst+Pfister. In this way  deformations  are avoided, the rings stay round and their surface is kept smooth.

 

One by one

Once at Digmesa, the O-rings are taken from their  bag  and  enter  the  fully  automated  assembly  via  a  chute. “The  chute  gives  the  rings  a  thorough  shake  to move  them  on,”  says  Yves  Riedo.  But  this  carries  the risk of  the rings sticking to one another rather than advancing  to  heir intended  destination  in  the  flow sensors. “We solved this problem with a special surface treatment,” relates the product manager Enrico Donati. The microtalcing treatment functions like baby powder and keeps the PERTEC® O-rings separated by reducing the adhesion typical for silicones.“As a result,  Angst+Pfister  has  significantly  reduced our rejection rate,” Michael Perret,production leader at Digmesa, is pleased to report. “We used to treat the surfaces ourselves, now we can rely on the competence of Angst+Pfister.” When the rings are not perfectly circular and smooth, or they clump together during assembly, then the machines stop – and have to be restarted manually. That costs time and money.  

 

Many markets – one product

Angst+Pfister’s PERTEC® O-rings have one more advantage: They comply with all the industry-specific approval  requirements  of  the major markets, whether it is approval for the European, Chinese, South American or US markets. “This is an emerging trend,” Reto Müller acknowledges. In the past compliance with the requirements of the US markets was generally sufficient for the international companies. Nowadays, more businesses than ever before are attempting to comply with the specific health requirements of all the markets. Angst+Pfister’s PERTEC® products meet those requirements. So now, how about a perfect cappuccino?  

 


Flow meter with PERTEC® O-ring
 


The PERTEC® Angst+Pfister O-rings meet all industry-specific approvals for the major markets.


 

Learn more about our elastomer compounds

 


 



published: Aug 24, 2020, 10:09:00 AM  by: Angst+Pfister Group