For even better performance
With Persisto® 8400 Burckhardt Compression is following its strategy of developing sealing material specialized for use in reciprocating compressors. The material properties have been improved to offer you even better performance. It replaces Persisto® 1025, 1026, and 1027 in all applications. And best is that no changes to your system are required.
Persisto® 8400 is a PEEK-based material for high-pressure and high-temperature applications in
oil-lubricated or dry-running service. The proprietary composition of Persisto® 8400 leads to improved mechanical strength for demanding high-pressure applications and excellent tribological behavior in dry-running systems. The higher elongation at break enables the design of one-piece piston rings, even for small piston diameters, that are easy to install.
Behavior under nitrogen compression
The wear behavior of Persisto® 8400 has been tested in a dry-running nitrogen test compressor at a discharge pressure of 40 bar and a static pressure difference of 100 bar in a tailrod packing. The calculated wear coefficients are significantly below those of Persisto® 1027.
Persisto® 850 / 851
Your ideal partner for hydrogen applications in dry-running machines
With Persisto® 850 and Persisto® 851, Burckhardt Compression offers two materials that have been specially developed for sealing applications in dry-running reciprocating compressors. Persisto® 850 and Persisto® 851‘s wear behavior is superior to that of all common materials for hydrogen compression, and the products can be applied at higher pressures thanks to improved pressure and creep resistance.
Manufactured in a hot-pressing method, Persisto® 850 has been specifically optimized to display good pressure-creep properties and high wear resistance for hydrogen applications at high pressures and can be used up to a cylinder pressure of 330 barg (4790 psig) and a packing pressure of 200 barg (2900 psig). For lower pressures of up to 50 barg (725 psig), the Persisto® 851 is recommended, which is produced by a standard sinter process.
The highly-optimized alloy comprising PTFE and PPS is of particular importance for both materials. In the case of Persisto® 850 with its special processing, this offers favorable properties for the requisite sealing functions and permits a higher load and a reduced creep compared to conventional filled PTFE materials and polymer blends. At the same time, sealing and rider rings made of Persisto® 850 and Persisto® 851 display good flexibility and correspondingly good adaptability.
Scope of application
Persisto® 850 und Persisto® 851 can be used in a wide range of gases and gas mixtures, but they are not recommended for compressing oxygen-containing gases. Apart from hydrogen, these two new materials are predestined for applications with various hydrocarbons (incl. boil-off gas), carbon monoxide, carbon dioxide or ammonia. Thanks to its special composition, the atmospheric dew point of the gases can be significantly below –70 °C (bone-dry). As Persisto® 850 and Persisto® 851 do not contain any abrasive fillers, expensive counter body materials or coatings can be dispensed with.
Burckhardt Compression‘s line of Persisto® 850 products sets it apart as a specialist offering new solutions for complex sealing applications in reciprocating compressors. Together with innovative ring designs and heterogeneous Redura® sealing system, the custom-made Persisto® 850 compounds are efficiently and reliably moving the ranges of application toward higher pressures. Burckhardt Compression guarantees the longest service lives as well as increased reliability, thereby pushing the limits of the possible.
The newly developed Persisto® 870 pushes the limits of PTFE-based sealing elements to higher pressures, resulting in a number of benefits. PTFE-based materials offer outstanding chemical resistance and are much cheaper than those made from hightemperature polymers such as PEEK. Furthermore, PTFE-based sealing elements can be used in combination with low-cost counterpart materials such as gray cast iron instead of nitrided or tungsten carbidecoated steels.