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on packed seals for pumps and valves,
and screenin8 t,ests have been made on
a number of packing materials for
possible use as. lubricants. The test
consisted of heating the material
under compression to 1500°F for a
period of time and then comparing the
heated material with the original
material. The materials tested
included C (graphite), PbO, Ni,O,,
Ni,O, -t- PbO, PbO -t Mo, Ni,O, + MQ,
CrF,, Ni,O, + C, PbO -t C, Pb,(OH),CrO, I
wloS2, Ni 203 + MoS,, MoS, + Mo, RN + MoSz,
BN, Ni,O, + BN, 8N -t- C, ZnS, CeO,, and
CaF,. The tests indicated that the
following materials may possibly be
useful as high-temperature lubricants:
C (graphite), Ni,O,, Ni,O, + Mo,
Ni,O, + C, FiIoS,, MoS, f Mo, MoSz + BN,
and BN + C. CeO, [nay be a fine
abrasive. It is planned to iurther
test these materials in contact with
fluorides.
One test apparatus for screening
materials has been built and operated
that consists of a fluoride pot with
stuffing boxes on the top and bottom.
A single shaft is inserted through
both the stuffing boxes, and the
material to be tested is contained in
the spring-loaded glands. The shaft
is reciprocated by an air cylinder,
and the power requirements can be
measured. Graphite and MoS, have
been tested at 1000CF in this device
with no fluoride leakage out of the
stuffing boxes. However, the fluoride
wets the surface of the shaft and is
carried into the packing where it
causes the shaft to bind with the
packing, and the power requirement
becomes excessive. Mixtures of
graphite and MoS2 with powdered
fluoride have also been tried in
these glands, but; there was no fluoride
in the pot, The results were similar
in that the powdered fluoride melted
and caused the gland walls and the
shaft surface to bind.
One other t,est device that is being
assembled has identical packings
located at, each end oE a lantern gland
PERIOD ENDING DECEMBER 18, 1952
in a heated container with a rotating
shaft t,hrough the assembly. The
equipment is designed so that liquids,
such as fluorides or lubricants, can
be introduced under pressure into the
lantern gland. This assembly is
mountedso that spring tension prevents
rotation, and the torque required for
operation can be measured.
Packing Compression Tests. As
reported previously,(2) experience
with high-temperature packing materials
indicates that in almost every instance
stuffing boxes have required re-
tightening after they reached operating
temperature. Therefore a series of
tests have been run on various materials
to determine their compression charac-
teristics. A dial indicator for
measuring the expansion or contract,ion
of the material being tested was
mounted on the test apparatus. In
the tests, a 1-in.-thick layer of the
material being tested was subjected
to a compressive force of 75 psi arid
the cornpression was measured. The
material was then heated to 1500'F
and held at that temperature until
the dial indicator showed no further
change. After reaching this equi li brium
condition, the material was held at
1500'F for a further period of 1 hr,
and the compression was again measured.
The change in compression, that is,
the difference between the compression
before heating and the compression
after heating, is given in Table 2.1.
This test procedure was repeated
several times for each material. In
all tests thus far, with the exception
of the test of nickelic oxide, there
was little, if any, further dimensional
change after the initial heating.
Pack i n g P en e t r at io II Te s t s. A
series of tests has been run to
determine the wetting susceptibility
of various materials. The material
to be tested is compressed by a heavy
washer and screw in a container.
('ID. R. Herd, H. R. Johnson, end R. N. Mason,
ANI' Quar. Prog. Rep. Sept. 10. 1952. OWL-1375,
p. 19.
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