Parr Instrument Series 3900 - Manual (Page 11)

Hydrogenation Apparatus
w w w . p a r r i n s t . c o m 11
Semi-micro Operations
Small samples can be treated in a 3911 Hydrogena-
tor by replacing the standard 500 mL bottle with
a smaller 250 mL bottle (66CA2). This requires a
101CA2 spacer to compensate for the difference in
bottle heights. To install the 250 mL bottle, remove
the stopper and the 61CA4 washer from the gas
inlet tube and slide the 101CA2 spacer onto the tube,
then clamp the bottle and spacer in the holder in
the usual manner. Since small samples may require
only small amounts of hydrogen, it may be advanta-
geous to replace the standard four liter hydrogen
tank with an alternate one liter tank (A16CA2) for
semi-micro operations. The same tank valves are
used on both sizes and are easily transferred to the
small tank.
Augustine (reference 1 on page 15) describes an
interesting holder for handling small samples in a
3911 Hydrogenator which he prepares by sealing a
50 mL or smaller heavy walled fl ask inside a larger
bottle.
Alternate Parts
If bottle pressure measurements are not required,
the gage can be removed from the 3A93CA valve
assembly and replaced with a 94CA plug.
Tefl on tubing can be furnished in place of the stan-
dard 119CA polypropylene tube for use with chemi-
cals which might attack polypropylene. The same
fi ttings are used to attach either Tefl on or polypropyl-
ene tubing to the 3A93CA valve.
Maintenance Instructions
Periodic cleaning may be performed on the exterior
surfaces of the instrument with a lightly dampened
cloth containing mild soap solution. All power
should be disconnected when cleaning the instru-
ment. There are no user serviceable parts inside the
product other than what is specifi cally called out
and discussed in this manual. Advanced trouble-
shooting instructions beyond the scope of this
manual can be obtained by calling Parr Instrument
Company in order to determine which part(s) may
be replaced or serviced.
The connecting rod has oil-impregnated bronze
bearings which do not require heavy lubrication.
Place a drop or two of light oil on each bearing
about once a month. Lubricate the fl ywheel shaft
by placing a few drops of light oil in the oil cup at
regular intervals. A light application of a lithium
grease such as “Lubriplate” on the shaker pivots is
also advisable. The spacing of these pivots should
be adjusted so that the bottle clamp swings freely
without excessive friction.
To inspect and replace the valves, unscrew the 8VB2
packing nut and remove the needle and knob. The
internal parts can then be removed with a small
wire hook. These will come out in the following se-
quence: 6VB packing cover, two 4VB3 packing rings,
21VB lantern ring, and 20VB valve seat. If the plastic
valve seat will not slide out of its socket, use a 1
1/2” wood screw as a removal tool. Replace these
parts in the same order; insert the valve needle and
tighten the 8VB2 packing nut fi rmly with a wrench.
Caution: Always back the valve needle away from its
seat before tightening the packing nut.
It will be necessary to use a new plastic ferrule in
the A102CA connector whenever a new polypropyl-
ene tube is installed. A new A102CA connector is
furnished with each replacement A154CA polypro-
pylene tube so that a complete set of parts will be
available when changing tubes. If the body and cap
nut in the old connection are in good condition they
can be used with the ferrule from the new connec-
tor. But if there is any question about the old parts,
discard them and install a new connector. The steps
required to attach the tube to the connector are as
follows: Be sure that the end of the tube has been
cut squarely; then disassemble the connector and
slide the cap nut and ferrule onto the tube. Insert the
tube into the connector body and tighten the cap
nut fi rmly.
Fuse Ratings
The replacement of protective fuses should be per-
formed by qualifi ed personnel.
Parr No. Type Ratings
139E21 Slo-blo 5 Amps, 250 Vac
139E20 Slo-blo 4 Amps, 250 Vac
139E8 Slo-blo 2.5 Amps, 250 Vac
139E25 Slo-blo 10 Amps, 250 Vac
139E26 Slo-blo 6 Amps, 250 Vac
Note: Check the labels on Switch Box for cor-
rect fuse rating.