3B Scientific Critical Point Apparatus - Manual (Page 13)

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Subject to technical amendments
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12.3 Assembling the equipment:
In case castor oil had been removed from the oil
chamber:
• Pour a fresh quantity of castor oil in up to about
5 mm below the upper edge of the cylinder (at
the beginning of the depression).
• Insert both of the silicone seals.
• Turn the conical seal inside out and dampen the
stud with some castor oil then screw it into the
guide tube.
• Unfold the conical seal back to its original shape,
position the spring on the piston and insert the
guide tube into the piston.
• Mount the measuring cell and position it flush
along the edges of the cylinder.
• Place the heat casing at the centre of the lower
silicone seal.
• Fit the circular grommet and, with the help of a
ruler placed on the heat casing, position it paral-
lel to the cylinder (see Fig. 9, the semicircular
holes should then be below the valve openings).
Fig. 9: Positioning the circular grommet
• Place the valve plate at the centre and position it
parallel to the end plate.
• Fit the M8
×40 screws with new copper gasket
washers and loosely screw them in.
• Tighten the screws. Take care to ensure that there
is uniform pressure on the circular grommet (if
the pressure is too high, the grommet makes a
greyish mark on the transparent acrylic, whereas
if the pressure is lower the surface looks milky).
12.4 Recommissioning:
• Degas the hydraulic fluid and pour the oil into
the equipment (see chapter 10).
• Position the safety valve (see chapter 10).
• Conduct a fresh volume calibration (see chap-
ter 6).