Appeal No. 97-3717 Page 17
Application No. 08/397,163
sealing surface for contact with a sealing member 12. The
actuating element 2 has an upper end piece or spacer 22b.
Newcomb teaches (column 3, lines 38-47) that (1) the valve
body 21 and the lower end piece 2a of the actuating member 2
were made from steel having a thermal expansion coefficient of
12 Fm K ; (2) the piezoceramic material forming the actuating-1
member 2 has a thermal expansion coefficient of 4 Fm K ; and-1
(3) the upper end piece or spacer 22b of the actuating member
was made from aluminum having a thermal expansion coefficient
of 23 Fm K .-1
Newcomb discloses (column 3, lines 52-68) that
[t]he length of the aluminum end piece 22b is
determined as follows. In operation of the valve any
thermal expansion of the steel valve body 21 and end
plate 14 would result in the distance between the side
with the plate 14 and the open side of the valve housing
becoming larger. The same temperature change would cause
the aluminum end piece or spacer 22b, the element 2 and
the lower end piece 2a to expand in a direction away from
the end plate 14. The axial lengths of the parts 22b, 2
and 2a can be calculated so that the thermal expansion
coefficient of these parts together corresponds to that
of the body 21 and end plate 14.
In this way, the lower surface of the lower end
piece 2a where it makes contact with the movable body 6
can be maintained in a substantially fixed position with
respect to the seat end of valve housing 21 even though
changes in the temperature of the valve may take place.
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Last modified: November 3, 2007