Custom machined seals raise the bar for reliability in chocolate manufacturing

The company turned to SKF after facing repeated failures in the seals on needle valves used on its chocolate depositing machinery. The valves control the flow of liquid chocolate heated to 30°C and pressurised to 10 bar, ensuring that each product on the manufacturing line receives precisely the correct amount of chocolate. Each depositing machine has 72 valves, but the company’s previous seal design – a moulded product from another seal supplier – was suffering intermittent failures in production. When the needle valve seals failed, excess chocolate would leak into the production environment, resulting in reject product and costly downtime as machines were stopped for cleaning and seal replacement.

After investigating the issue, SKF engineers suggested a new seal design, based on its S01-P profile, a special asymmetric shape originally developed for demanding rod-sealing applications in high pressure hydraulic equipment. To produce a seal suitable for use in the food manufacturing environment, SKF used its proprietary CNC manufacturing capabilities to create special seals using H-Ecopur-95A-Blue, a polyurethane seal material engineered specifically to meet the regulatory and operating requirements of food and beverage manufacturing.

The food manufacturer tested the new seal design at a manufacturing plant in Canada. During 12 months of full production the company experienced no seal failures or leakages. It has now decided to install the new seals at all six of its production sites world-wide that use the same chocolate depositing equipment.

“This application shows the true value of our machined seal capabilities,” says Jade Gilroy, channel and platform development manager seals at SKF. “We were able to propose a fast, effective custom-design solution and to manufacture the seals within a short a period of time.”