Installation Manual

ValveWatch II Hardware Installation and Setup Manual
Page 27 of 34
CRANE
Nuclear
8.4 Preparing the Valve Yoke Surface
• There are three things to remember for successfully mounting a strain sensor every time.
CLEAN, CLEAN, CLEAN. A CLEAN yoke surface, a CLEAN sensor face and repeating the
cleaning process until the Lent free wipes are as clean after the process as they were when you
started the cleaning process.
• The prepared yoke surface area should be slightly larger than the strain sensor body diameter.
• The area should be filed, sanded, or ground to achieve a flat (to within 1/16in), bright, bare-
metal, crosshatched surface finish. We recommend using a small, variable speed hand grinder
at low speed (500 to 1000 rpm) with a 60 to 80 grit silicon carbide or aluminum oxide wheel.
The area should be free of all paint, primer, or surface coating. Experience has shown that a
vibrating etch tool works well for cleaning paint from the surface.
• The area should contain no significant casting lines or other such indications that have not
been blended into the flat surface.
• The area should be essentially in the same plane over the length of the strain sensor housing.
• The area may be curved over the width of the strain sensor assembly.
• The yoke mounting area and sensor mounting face must be cleaned to be free of all grease and
oily residues prior to bonding.
• Suggested degreasing agents are:
- Denatured Alcohol
- Ethyl Alcohol
- Methyl Alcohol (Technical Grade)
- Naphtha (Technical Grade)
- Acetone
• Use these or other degreasers specifically approved by your company. A stronger
degreaser/solvent than those listed above may be needed to remove grease and oily residue.
• Remove the sensor cap and use the degreaser agent to assure no oil or dirt buildup on the
sensor has occurred during handling or inspection
• All surfaces must be dried with a lint free cloth prior to solvent evaporation.
• Repeat the degrease process on both surfaces just to be sure everything is clean.
Caution:
The sensor must be installed within 15 minutes of sanding and cleaning. Passivation of
stainless steel surface accelerates after 15 minutes.
Always read and understand safety data sheets prior to using cleaning solvents.
Caution:
It is strongly recommended that safety glasses and gloves be worn during this procedure.
Caution:
Follow site specific work permit requirements for work in an explosive environment.