Materials needed to prepare mantle. Solid dry ice (box at left) is run through grinder to
obtain powder which is spooned through funnel into thermometer well. Thawing rod,
small rubber insert, and alcohol are used during operation.
d. HANDLE WITH CARE. Do not shake or invert the Equiphase Cell vigorously.
Violent agitation of the sealed-in water could break the inner glass cell.
e. DO NOT OVERFREEZE. When freezing the ice mantle, do not allow a heavy crust of
ice to form across the surface of the water inside the glass cell. Bridging of the ice may
be prevented by warming that portion of the glass cell with the hand while shaking the
cell gently to agitate the surface of the water. Failure to take this precaution may result in
a broken cell. Similarly, be sure that the mantle does not touch the glass at any point
along the side or bottom of the cell.
f. PROCEDURES. Brief step-by-step instructions are included on the nameplate of each
Equiphase Cell. These are intended mainly as a quick reference for personnel who have
gained familiarity with the Equiphase Cell. They do not replace the more detailed
procedures given below. Material in this subcourse should be thoroughly understood
before an attempt is made to freeze the Equiphase Cell. Should any doubt arise as to
proper procedure, contact your supervisor. Do not risk breaking a cell.
To Establish Triple Point Temperature (0.01,C):
Remove cover and slowly invert cell to drain re-entrant well.
To freeze cell, fill with powdered dry ice. Replenish until ice mantle forms around
CAUTION: Overfreezing will destroy cell. See detailed instructions.
Add several cc of alcohol to well. Lower small piece of flexible material to
bottom of well to prevent bottoming of thermometer on glass.
Free ice mantle from well by lowering thawing rod (any room- temperature rod
3/8 inch max. dia.) into well. Repeat as necessary.
Rotate cell. Ice mantle, when free, will rotate on well. Triple point temperature is
now established and will be maintained until bottom of mantle melts, as
evidenced by flotation mantle. (See figure 4)