Conches are difficult to seal. Leakage causes product loss, housekeeping issues and many other time-consuming problems. The work environment becomes challenging, with safety issues arising that may hurt employee morale and gain the attention of the Occupational Safety and Health Administration (OSHA).

In one Midwest chocolate facility alone, the losses totaled $2 million, and the quantity of chocolate that leaked onto the floor filled multiple waste barrels (see Image 1). The traditional method for sealing conches and other, less specialized mixers has been compression packing or mechanical seals. While effective in a wide range of applications, these have not solved the problem of leaking conches.

Traditional conche sealing failures

The shaft movement on conches tends to open clearances between packing and the shaft and damages faces in mechanical seals. This alone leads to instant leakage. Even without shaft movement, the inevitability of shaft wear over time remains with packing and face wear with mechanical seals.  As wear occurs, leakage increases, accelerating required maintenance. All of this leads to an ongoing cycle of product loss, maintenance and seal replacement.

The chocolate solution

An air seal solved the chocolate conche-sealing dilemma experienced by the Midwest producer (see Image 2). This technology is a non-contact sealing device that uses air to form a pressurized barrier between the product and the environment. To form this barrier, air is delivered to the seal and fed through a tight clearance throttle. Furthermore, this throttle handles shaft runout while maintaining the pressurized barrier and without wearing the shaft. No maintenance is required. Its design allows for the technology to seal 100 percent of the product and last for the life of the asset. 

At the Midwest plant, the waste, housekeeping issues and potential OSHA violations were eliminated following the installation of the air seal technology, which provided complete containment of the chocolate with no leaks. This chocolate producer plans to add air seals to its existing conches. In addition, six other confectioners in the U.S. are considering the air seal as their conche and mixer leakage solution.


Adding air sealing technology to chocolate conches allows end users to experience a dramatic reduction in operational costs and the mitigation of maintenance, repair, and clean up. Perhaps even more important, costly product loss is eliminated. For more information, visit or email