A compensation device for a valve compensates for expansion of a valve
stem and/or inertial effects during operation of the valve. The
compensation device is preferably integrally provided with the valve. The
compensation device includes a first plate rigidly connected to the body
of the valve and a second plate movably coupled to the first plate. The
second plate is rigidly coupled to the operator assembly housing that
houses and controls the movement of the second end of the valve stem, so
that movement of the second plate relative to the first plate moves the
operator assembly relative to the valve body to compensate for expansion
of the valve stem and/or inertial forces. The first plate and second
plate remain in radial alignment during the relative movement. One or
more biasing elements, such as spring assemblies, are used to connect the
first plate and the second plate to bias the plates in a default
position, absorb forces and allow for movement of the second plate
relative to the first plate. The spring assembly preferably comprises an
array of Belleville washers.