Whenever a thermocouple must be welded in place it is advisable to use a weld pad and weld clips to protect against burn-through of the sheath material during field installation. Sandelius weld pads, weld clips and weld pad covers are available in a wide reange of styles and materials.
Standard W1, W2 and W3 Style weld pads measure 3/4" x 3/4" x1/8". Inconel 600 or 310SS have proven to be excellent choices for most furnace applications, other materials are available on request.
Add forming information as required. If forming is specified, the thermocouple sheath will lay parallel to the process tube.
Formed so the thermocouple sheath wraps around the process tube. The amount of arc desired as well as the tube size should be specified on your order. (SHown with a Flg. 1 bend=90º.) Note "L" length of the T/C is measured from the center line of the tube.
Wedge-Shaped Weldment
The design offers an alternative to the traditional weld pad for .375" or larger diameter sheath sizes. If incorporates a specially shaped weldment to keep the thermocouple junction in contact with the furnace tube surface. (W6E is shown with a Flg. 1 bend a=90º.)
Material Designations:
A = 316SS
B = Inconel 600
C = 304SS
D = 310SS
E = 446SS
Y = Other as Specified
All Sandelius weld pad covers are supplied packied with insulation suitable for use to 2300º F, covers should be welded in place with insulation left inside.
TYPICAL WELD PAD INSTALLATION AND EXPANSION LOOPS
The following are examples of commonly used bend and expansion loop configurations, many other configurations are available on request. If you are unsure of how to specify the exact configuration you require simply include a sketch with your order.
Wedge-Shaped Weldment
The design offers an alternative to the traditional weld pad for .375" or larger diameter sheath sizes. If incorporates a specially shaped weldment to keep the thermocouple junction in contact with the furnace tube surface. (W6E is shown with a Flg. 1 bend a=90º.)
Legend L = The total straight length of the thermocouple sheath before bending as shown in the drawing of each assembly style on this page. In assemblies including expansion loops and/or bends this length should be specified as "00" in the part number allowing us to make the necessary calculations. Lc = The " point of measurement" toward the "cold" or reference and of the sheath. "Lc" is constant as shown in the drawing of each assembly style on this page. M = The first "point of measurement" back from the "hot" or measuring junction end of the thermocouple. On a straight assembly with no bendfs. M points of measurement will vary with the type of bend as indicated in the figures above. B = The straight length of sheath between the center of an expansion loop and next measuring point toward the "Hot Junction", usually "M: (Used only when an expansion loop is specified, if no expansion loop is specified "B" is left blank. C = The stright length of sheath between "Lc" and the first point of measurement" encountered; usually either the center of an expansion loop or M.
a = Degrees of arc in a bend. D = The outside diameter of a circular expansion loop. 1 = Thermocouple Sheath 2 = Weld Pad 3 = Weld Clip 4 = Weld Pad Cover (Dotted for clarity) 5 = Correct View to determine R (right) or L (left) side orientation of an expansion loop.