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The mechanism for sealing elements into probe bodies varies. For example, the cylindrical type elements
are sealed with an all metal weld, whereas flush elements are sealed with an epoxy seal. The sealing
mechanism of the element is a primary factor in determining the temperature and pressure rating of an
ER probe.
Table 2 provides a guide to temperature and pressure limitations for various element designs.
Table 2. Element Temperature and Pressure Ratings
Note: The temperature and pressure limitations given above may be subject to modification according to
the probe body design. This is discussed later in this manual.
A final issue with respect to sensing elements is material of construction. Generally, this should be
selected to most nearly match that of the plant or equipment under consideration. Almost any geometric
configuration and thickness of element can be made in any commercially available alloy. However, some
alloys, particularly in the glass sealed loop version, may be costly and have a considerable delivery time.
