Seal configuration used in unique retractable tank spray system

Spraying systems are incorporated into tanks to clean them. Generally the spray head is now retracted automatically from the tank.

Sealing issue:

Trelleborg Sealing Solutions worked with a manufacturer who was developing a unique retractable spray ball system. It operates pneumatically which allows it to have the major benefit of being self-draining. A complete sealing configuration was required which could operate with liquid on the one side and air on the other. Under pressure from both sides and at high temperature, seals in contact with cleaning media had to withstand the harsh chemicals used in these regimes.

Sealing requirements:

• High chemical resistance
• Chemically resistant to all types of CIP media
• Compliant with FDA and USP Class VI standards

Solution:

Trelleborg Sealing Solutions recommended a configuration of seals including a Turcon® Variseal®, along with O-Rings in EPDM and Isolast® options depending on chemical resistance requirement. The surface of the elastomer O-Ring at the neck of the spray ball was treated with FDA compliant FF coating. This gave the seal the necessary friction characteristics to allow smooth dynamic operation of the spray head.

Result:

The seal configuration withstood extensive tests. After cycles of 1,000 operations, there was no leakage and pressure was held. The seals also continued to perform after a temperature test where the units were heated up to 140°C / 284°F for 24 hours.

More information on EPDM
Find out about Isolast®