Inspect The Nozzle - Delta Controls HTP Installation, Operation And Maintenance Manual

Inspect the Nozzle

Because the "as-built" dimensions of the refractory and nozzle can (and often do) differ from the design
specifications, it is important to verify these dimensions before installing the thermocouple. Installing a
thermocouple that is not properly sized for the nozzle and refractory can result in breakage or inaccurate
measurements.
Inspect the inside of the vessel nozzle. The inside
of the nozzle should be clean and free from debris and
welding slag. The hole cut through the vessel shell at
the base of the nozzle should be a minimum 3-1/2" (90
mm) diameter. The top refractory surface should be
even and free from extensive damage. The bored hole
through the refractory should be clean, 2.2" to 2.4" (56-
61mm) diameter, centered in the nozzle and in
perpendicular alignment relative to the nozzle flange
face. If the hole does not meet the above criteria, the
thermocouple can become broken shortly after start up
as refractory begins to shift.
Check the nozzle and refractory dimensions.
(Refer to the drawing on the cover of this document)
To ascertain Insertion Length "F", lay a straight edge
across the flange face and with a measuring tape,
hook the inside surface (hot face) of the refractory
inside the vessel and measure up to the straight edge.
Confirm this dimension is the same as the length of
the thermocouple element well as measured from the
thermocouple flange to the tip of the well.
(If the thermocouple element well is too long, it will
contact the refractory well when it is inserted, causing
it to become broken. If the thermocouple is too short,
it may read erroneously low.
HTX
Thermocouple
shown
Insertion
Length "F"
Insertion
Length "F"
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