Patent ID: 7540431
Filing Date: 2009-06-02
Classification: F28F,G05D,Y10T

Abstract:
1. A by-pass valve for a heat exchanger circuit, the by-pass valve comprising: a housing defining communicating first and second bores therein, first and second main ports communicating with the first bore, and at least a further port communicating with the second bore, the second bore having a central axis and a peripheral valve seat about a valve opening facing the first bore; a temperature responsive actuator located in the housing and having a reciprocating central shaft disposed along said central axis, the central shaft having a closed end portion; an annular sealing member slidably mounted on the central shaft and extending outward from the central shaft to engage the valve seat and, together with the closed end portion, close the valve opening; bias means for urging the annular sealing member toward the valve seat; and a coiled return spring mounted in the housing for urging the central shaft closed end portion to retract and open the valve opening, the return spring having a first end connected to the closed end portion and a second end engaging a spring support in the housing facing the first bore, the return spring having a larger diameter at its second end than its first end, wherein along a first axial length of the return spring, coils of the return spring have decreasing diameters as the distance of the coils from the first end increases, and along a second axial length of the return spring that is further from the first end than the first axial length, coils of the return spring have increasing diameters as the distance of the coils from the first end increases.