Preparation of high porous metal filter element for the fail-safety function

The fail-safe filter element is an assistant filter mounted in a filter unit to intercept particle leak when parts of the main filter elements are broken. The filter element should be plugged easily to meet the sealing purpose and should have high permeability to save the mounting space. This study focuses on the preparation of the high-permeability metal filter element. The filter elements were fabricated by using the cold isotropic press (CIP) method and the binding (BD) method. The permeability of the filter element was effectively controlled by the following factors: material size (54–840 μm), CIP pressure (1.2×108–2.0×108 Pa), sintering temperature (1423–1523 K) and time by CIP method. The high porous filter element of 9.2×10−11 m2 permeability was prepared in optimal conditions using 420–840 μm metal powder, fabricated at CIP pressure of 1.7×108 Pa, and sintered at 1473 K for 1 h. The pressure drop across this filter element was six times less than that of the commercial ceramic filter element used in the main filter element. The metal filter element with a higher permeability of 2.76×10−10 m2 was also prepared by BD method by using 540–840 μm metal powder.