A check-valve prevents reverse flow of fluid. According to the specification of the application zero leakage may be required.
Generally our check-valves are tested for a leakage < 1 bubbles/min at zero to 5 psi back pressure, independant of specified crack-pressure.
In sizing a check-valve it has to be taken into account that a high crack-pressure and/or oversized valve tends to let the valve chatter, which may cause pressure waves in the system and thus premature wear of all components involved.
Our range of products now includes a large variety of special solutions, e.g. without spring, to serve individual needs of customers. Materials like PVDF, PEEK, Hastelloy or Inconel can be used according to their mechanical property.