Patent ID: 7564327

Claim:
A filter compensation assembly for thermal compensation of a filter cavity assembly having an end wall and a housing, said assembly comprising: (a) a lever element having a first pivot point at one end, a second pivot point at the other end and a third pivot point positioned in between the two ends, where the lever element is pivotally coupled at the first pivot point to the end wall; (b) an anchoring element pivotally coupled to the lever element at the second pivot point and secured to the housing of the filter cavity; (c) a thermal expansion element having a lower coefficient of thermal expansion than the filter cavity assembly, said thermal expansion element having one end pivotally coupled to the lever element at the third pivot point and the other end secured to the housing of the filter cavity; (d) such that the difference in the coefficient of thermal expansion between the thermal expansion element and the filter cavity assembly causes the lever element to articulate and to displace the end wall to achieve thermal compensation and wherein the degree of displacement of the end wall caused by the lever element is proportional to the ratio between the distance between the second and first pivot points and the distance between the second and the third pivot points.