The Type CK 725 is a dual-pressurized, liquid-lubricated cartridge seal for top-entry mixing and agitating equipment. A value-engineered design, high level of standardization and broad material options make this seal a cost-efficient solution for general-duty applications in the chemical and pharmaceutical industry. Standard versions are compliant with vessel seal standard DIN 28138 Parts 1 and 3. They are designed for use on steel-made agitated chemical reaction vessels to DIN 28136, to fit on a mounting flange to DIN 28141 and agitator shaft end dimensions to DIN 28154. Hardware adaptations to fit to non-DIN equipment are available on request.

By exchanging the seal faces, a Type CK 725 wet seal can easily be converted to a contacting, dry-running seal. Type name then changes to Type CK 725D. Advantages of contacting dry running seals include freedom from contamination by barrier liquid and a low face wear rate, together with a cost-efficient, easy-to-install (gas) supply system. To simplify inventory, seal components are standardized with the other seal types of this family CK 726(D) and CK 736(D).

The seal is suitable for operation in potentially explosive atmospheres. Depending on individual explosion protection requirements, the seal operating limits may differ from the values given in the parameters section. Furthermore, additional monitoring devices may be required.

For undemanding applications, the wet seal versions can be operated without pressurizing the barrier liquid. Please consult John Crane.