Note: Descriptions are shown in the official language in which they were submitted.
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OIL ~ND LUBRICANT_DEGRADATION DETECTOR
_NTRODUCTION
This invention is related to a means for
detecting chemical degradation suffered by a pressurized
5 or unpressurized oil or lubricant subjected to elevated
temperature and more particularly to a means of
utilizing negatively charged sulfur ions produced as a
result of chemical degradation of a pressurized or
unpressurized sulfur containing oil or lubricant
10 subjected to elevated temperature to provide either a
corrosion product with positively charged copper ions in
the form of a coating that is able to provide
information with respect to the amount sf degradation
suffered by the vil ~r lubricant or combine with
15 available hydrogen in one form or another to form sulfur
containing acids that are able to erode away a component
producing the copper ions sufficiently to provide an
alarm signal when a predetermined amount of chemical
degradation has been reached.
20 BACKGROUND OF THE INVENTION
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The occurrence and build-up of foreign
particles and the degradation of oils or lubricants,
particularly when subjected to elevated temperature has
been a problem ~or many years. Of particular concern is
25 the amount of chemical degradation suffered by an oil or
lubricant contained within a housing, such as a gear
housing, after having been subjected to elevated
temperature and pressure over long periods of time such
as, for example, arising from friction and compression
30 associated with closely mating moving surfaces such as
between mating gear teeth.
Up until the time of the present invention,
attent;on has been focused upon the problem by utilizing
the magnetic or e~ectrical conducting properties of
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AI~L2~
forei~n particles to effect their isolatiorl or removal
or to provide an indication of their presence in the oil
or lubricant such as, for example, the magnetic filter
disclosed in United States Patent 3,].70,871; the
magnetic chip gauge disclosed in United States Patent
3,373,352; and the magnetic and non-magnetic chip
detector disclosed in Vnited Sta~es Patent 3,432,750.
Although United States Patent 4,008,4~4 - -
discloses a lubricant contamination warning device, the
device is limited to detecting the presence of ferrous
contamination as is the case with respect to the
ferromagnetic detector disclosed in United States Patent
4,100,491~ Other examples which utilize the electrical
conducting or electromagnetic characteristics of chips
or particles as a means of detecting their presence in
oils or lubricants include }he cletecting apparatus
disclosed in United States Patent 4,030,028; the chip
detection system disclosed in United States Patent
4,127,808 and ~he electromagnect:ic system disclosed .in
United States Patent 4,219,815.
Although the above detecting, isolation and
removal devices and systems may be used to advantage~
they are not able to detect che~i~al degradation
suffered by a pressurized or unpressurized oil or
lubricant subjected to elevated temperature which may or
may not contain such electrically conducting and/or
electromagnetic particles.
It is well known that many oil and lubricants
contain sulfur in one form or another and that a
particular oil or lubricant may contain a detergent that
contains sulfur in one form or another. Lubricants,
particularly lubricants derived from heavier crude oil
distillates, are apt to contain sulfur in the Eorm of
sulfuric acid and/or sulfuric acid esters. Detergents
are commonly used in oils and lubrican~s for dislodging
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solid matter and, if of an anionic sulfur containing
type, are apt to be present in the oil or lubricant in
the form of: carboxylic acid salts such as alkyl-COONa;
or sulfuric acid ester salts such as sulfated fatty
alcohols such as alkyl -0S02-ONa, sulfated
monoglyceridesr sulfated olefins or sulfated amides; or
in the form of sulonates such as alkyl-SO2ONa or
paraffin -SO2ONa or napthene-SO2ONa; or other ~ulfur
containing complexes~ Oils and lubricants designed to
with5tand elevated temperature and/or pressure (commonly
called extreme pressure lubricants) often contain ~ulfur
in one form or another and are able to provide
negatively charged ~ulfur ions as a result of
degradation arising from exposure to elevated
temperature. Oils and lubricants containing sulfur are
often referred to as "sulfur reactive" and, as
hereinafter used, the term "sulfur reactive" shall mean
that ~he oil or lubricant contains sulfur in one form or
another that is able to be converted into or otherwise
released in the form of negatively charged sulfur ions
as a result of degradation suffered by the oil or
lubricant arising from its exposure to elevated
temperature conditions. Although oils and lubricants
often contain antioxidants to re~ard degradation arising
from elevated temperatures, such antioxidants are
eventually consumed and sooner or later are no longer
able to prevent the production oE negatively charged
sulfur ions in the sulfur reaction oils or lubricants.
It has been discovered that the production of
negatively charged sulfur ions in pressurized or
unpressurized sulfur containing oil or lubricants
degraded by exposure to elevated temperature can be used
to advantage to form a corrosion product in the form of
a coating the thickness of which is indicative of the
amount of degradation suffered by the oil or lubricant
in addition to combining with hydrogen in one form or
another to form corrosive acids whose corrosive nature can
be used to advantage in determining when the degradation of
the oi'l or lubricant has reached a predetermined level.
~tatement of Invention
Accordingly, it is an object of the present
invention to provide a means of detecting the amount of
degradation suffered by a pressuri~ed or unpres~urized
sulfur reactive oil or lubricant subjected to elevate
temperature by utili~ing negatively charged sulfur ions
provided as a result of the degradation of the oil or
lubricant,
Accordi.ng to one aspect of the present invention
there is provided a detector for indica-ting the amount of
degradation suffered by a pressurized or unpressurized oil
or lubricant which provides negatively charged sulfur ions
in response to degradation arisi.ng from exposure of the oil
or lubricant to elevated temperature conditions, The
detector has componen~ means adapted to be exposed to the
oil or lubricant during the per:iod the oil or lubricant is
subjected to the elevated tempera-ture conditions, the
component means having at least a portion thereof made of
a material able to provide positively charged copper ions
under the elevated ~.emperature condition.s to which the
lubricant is ~ubjected and having a mass sufficient ~o
enable the electrical a~traction between the sulfur and
copper ions to provide a corrosi.on procluct in the form of a
coating that coats the component sufficiently to provide a
visual indication of the amount of degradation suffered by
the oil or lubricant.
According to another aspect of the invention
there i9 provided an apparatus for providing an electrical
warning signal that the amount of chemical degradation
sufered by a pressurized or unpressurized oil or lubricant
that provides negatively charged sulfur ions in response to
degradation arising from exposure of the oil or lubricant
lo to elevated temperature conditions has exceeded a
predetermined amount. The apparatus include component means
which is adapted to be exposed to the oil or lubricant
during the period the oil or lubricant is subjected to the
elevated temperature conditions, voltage means, warning
signal means~ and normally closed electrical circuit means
electrically connecting the component means~ voltage means
and warning signal means. The warning signal is
provided, as a result of the component means having at
least a portion thereof made from an electrlcally
2Q conductive material able to provide positively charged
copper ions under the temperature conditions to which the
oil or lubricant is subjected. The component portion has a
mass that enables the component portion to be eroded awsy
by sulfur containing acids arising Erom the degradation of
the oil or lubricant sufficiently to open ~he alectrical
clrcuit and enable the warning ~ignal to be energized by
the voltage means when the oil or lubricant degradation has
reached a predetermined amount.
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BRIEF DESCRIPTION OF THE DRAWINGS
.
FIGURE 1 shows a partial cross-sectional view
along the axis of a removably secured embodiment of the
detector of the invention;
FIGURE 2 shows a partial cross-sectional view
along the axis of a fixedly secured embodiment of the
detector of the invention; and
FIGURES 3 and 4 show a partial cross-sectional
view along the axis of embodiments of the detector of
10 ~he invention and a schematic of a typica~ electrical
circuit that is designed to provide a warning signal
when a predetermined amount of degradation has been
suffered by the oil or lubricant.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGURE 1 shows an embodiment of the detector of
the invention in the form of detector 20 that is able to
provide a visual indication of the amount of degradation
suffered by a pressurized or unpressurized oil or
lubricant containing sulfur that is subjected to
20 elevated temperature and able to produce negatively
charged sulfur ions as a result of such degradation.
Detector 20 has an annu]ar shaped body member 2
having external threads 7 for removably securing
detector 2Q to wall 6 of a housing, such as a gear or
2~ axle housing~ enclosing cavity 8 in which is contained
the sulfur reactive oil or lubricant. Cavity 8 may, for
example, be an unpressurized 5ump where oil or lubricant
is collected that has been subjected to elevated
temperature and pressure at some other location in the
30 system. A flange 4 is disposed between body member 2
and nut 3 at one end of detector 20 and a component 1
extends Erom the opposite end of body member 2 through
an opening, not referenced, in wall 6 into cavity 8.
Detector 20 is preferably positioned on wall 6 so -that
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component 1 is immersed in the sulfur reactive oil or
lubricant contained in cavity 8. Flange 4 is able to
compress seal 5 when nut 3 is tightened so as to prevent
leakage of the oil or lubricant from cavity 8. Although
5 detector 20 is shown as being removably secured by
threads 7 to wall 6, i~ is to be understood that such is
for illustrative purposes only and that any method of
removably securing detector 20 ~Q wall 6 that is able to
prevent leakage of oil or lubricant from the ~avity - ~
10 containing the oil or lubricant as well as enable
component 1 to be suitably immersed in the oil or
lubricant is considered within the scope of the
invention.
Although component 1 yreferably has a
15 cylindrical shape, component 1 may have any shape upon
the surface of which a coatin~ is readily visually
discernible. At least a portion of component 1 is made
from a material having properties ~uitably able to
withstand the temperature and pressure and corrosive
20 nature of the oil or lubricant in cavity ~ and is also
able to provide positively charged copper ions as a
result of the temperature and pressure to which the oil
or lubricant in cavity 8 is subjected. For embodiments
of the detector of the invention that are to be used for
25 visual indication~ of the amount of degradation to the
oil or lubricant, component 1 is provided with
sufficient mass such that it is not eroded away by
corrosive sulfur containing acids but rather is able to
resist erosion in favor of being a host for the coating
30 9 formed as a corrosion product of the positively
charged copper ions and the negatively charged sulfur
ions. Preferably, component 1 is made ~rom an alloy of
copper such as bronze or brass. Probe 1 may be secured
to body member 2 in any suitable manner. Body member 2,
35 flange 4 and nut 3 may be made from the same or a
_ 7 _ ~2~6~7~
different material than component 1. De~ector 20 may,
for example, be a one-piece construction made entirely
from a suitable bronze or brass.
Coating 9 is a corrosion product between the
5 negatively charged sulfur ions provided as a result of
the degradation of the pressurized or unpressurized
sulfur reactive oil or lubricant in cavity 8 having been
exposed to elevated temperature and the positively
charged copper ions available from component 1.
lO Typically, coating 9 is in the form of cupric or cuprous
sulphide or a mixture thereof. Although coating 9 is
shown as a coating over only a portion of component 1,
such i:s or illustrative purposes only and coating 9 may
be disposed onto the outer surface of component 1 in any
lS manner most commonly of which is when coating 9 is
substantially uniformly disposed over the entire surface
of component 1 exposed to the degraded oil or lubricant
in cavity 8. It has been found that for masses of
componen~ 1 suitable to resist erosion in favor of
20 enabling a buil~-up of coating 9, that the total
combined weight of componen~ 1 and coating 9 is greater
than the weight of component 1 alone. It has also been
found that the amount of build-up of coating 9 on
component 1 is related to the amount of copper present
25 in the alloy as for example where a component 1 made
from an alloy containing about 16% by weiyht of copper
and a component 1 made from an alloy containing about
65% by weight of copper were bo~h irnmersed in
unpressurized extreme pressure sulfur containing
30 lubricant for about 88 hours at 300F and upon
examination revealed a coating 9 thickness of abvut .003
inch on the component 1 made from the 16% copper alloy
and about .010 inch on the component 1 made from the 65%
copper alloy. A mass for component 1 found particularly
35 suitable for hosting build up of coating 9 in favor of
~2~6~
being eroded away by sulfur contair2ing acids is where
component 1 is made from a solid copper alloy rod having
a diameter of l/4 inch or greater~ Copper tubing may
also be ~lsed to advantage in making component 1 such as,.
S for example, copper tubing having a l/4 inch outer
~ic~meter and a .032-.035 inch wallO It can be readily
Ceen that detector 20 can be removed periodically from
cavity 8 and examined visually for ~he presence of
coating 9 the thickness cf which, as previously
lO-~escribed, is indication of the amount of clegradation
suffered by the oil or lubricant in cavity 8.
FIGURE 2 shows an embodiment of the detector of
~he invention in the form of detector 20A that is
fi~edly secured to wall 6A of a housing enclosing cavi~y
l~ BA which contains the sulfur reactive oil or lu~ricant.
Detector 20A has an annular shaped flange lO that,
~ependent upon the material from which flange lO is made
s e;.ther welded or brazed (reference ll) to wall 6A.
~etector 2~A has a component lA made from a ma.erial
2~ able to provide positively charged c~pper ions and a
~ass favoling build up o~- coating 9A as previously
~escribed with respect to component l o~ FIGURE i. Tl~e
suffixes "A", "B" and "C'i are used herein to refer to
~he corresponding components previously described hereln
25 with respect to detector 20 o~ FIGURE l for the sake of
convenience. Detector 20A of FIGURE 2 may be fixedly
secured to wall 6A in any suitable manner and may be
removably secured as previously described with respect to
FI~æ l. A willdow l~ is remova~ly secured to wall 6a suitably gasketed
3~ ~s shown by reference 5A such-that component l can be viewed Wi~lLn cavity ~3'~
without having to remove component lA from cavity 8A.
~indow 12 is rnade of any suitable transparent material
that is able to withstand the temperature and pressure
to which the oil or lubricant in cavity 8A is subjecte~
- 35 and which retairls transparency suitable enough to perm;t
P ~ ~3 --
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6~7~
compone~t lA to be viewed periodically to ascertain
whether any coating 9A, previously described with
respect to coating 9 of FI~URE 1, is deposited on the
outer surface thereof in order to determine whether the
5 oil or lubricant in cavity 8A has been degraded. In the
event that cavity is a collecting res~rvoir such ~s a
sump which is not under pressure, window 12 may not be
required and an opening through wall 6A may be all that
is required. Likewise, component lA may be fixedly
10 secured directly to wall 6A where such is des1red in
preference to the use of flange 10.
FI~URE 3 shows apparatus in the f,~-m o~ ~n
electrical circuit 19 in combination with an embodimen~
20B of the ~etector of the invention that h2s a
15 component lB having at least a portion there~f made ~rom
a positively charged copper ion producing ma~erial that
is able to be eroded away by the degradation products
arising from the degradation of pressurized ~nd
unpressurized sulfur containing oil or lu~ricant
20 subjected to elevated temperature~
Detector ~OB has a body member 2B that extends
through an opening, not referenced, in wall 6B of a
housing enclosing cavity 8B in which the sulfur reactive
oil or lubricant to be m~nitored is contained. Body
25 member ~B has external threads 7B which threadingly
secure detector 20B to wall 6B. Detector 20~ has a
flange 4B and a nut 3B as shown in FIGURE 3. Nut ~B, as
previously described for nut 3 of FIGURE 1, provides a
means for turning detector 20B so that it can be
30 threadingly secured to wall 6Bo Tightening deteotor 20B
against wall 6B causes flange 4B to press seal 5~
against the outside of wall 6B to prevent leaka~e of the
oil or lubricant from cavity 8s.
A pair of spaced-apart electrical condu~tors
35 extend through nut 3B, flange 4B and body member 2B into
cavity 8H for a distance sufficient to insure that
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component lB, which bridges across and provides an
electrical interconnection between conductors 13, is
immersed in the oil or lubricant con~ained within cavity
8B being monitored for chemical degradation.
Member 2B, flange 4B and nut 3B are made from
an electrically conductive material such as metal and
conductors 13 are electrically insulated from member 2B,
flange 4B and nut 3B by an electrically insulative
material 1~ such as a ceramic sleeve or other suitable
10 design and by electrically insulating gasket 14.
.Conductors 13 are threadingly engaged with insulation
material 12 ih ~uch a manner -as to prevent the oil or
lubricant from leaking ~ut of c2vity 8B.
C'omponent lB has at least a porti on thereof
15 made from an electrically conductive metallic material
that is a~le 'co provide positively charged copper ions
~s a result of e~posure of the sulfur reactive oil or
lubricant in cavity 8B to ele-~ated temperatures yet has
a mass sufficiently small to insure that is will be
eroded a~ay by s~lfur containing acids arising 25
degradation products of the oil or lubricant rather th-n
having sufficient mass to support the build-up of a
coating which is the corrosion product of positively
,char~ed copper ions and negatively charged sulfur ionC
25 as previ~usly ~escribed. Component lB is is preferabl--
in the form of a s~lid or stranded copper conducto.r
preferably of about ~0 to about 30 AWG~ Since a 30 A~
wire co~duct~r is substantially smaller in diameter,
mass, than a 20 AW~ w;re conduc~or will erode away ir
30 less time than a 20 AWG wire conductor at a lower le~r~~
of the oil or lubricant chemical degradation. It hac
been found ~or example, that 28 AWG copper wire will
erode completely in half when îmmersed in an extreme
pressure sulfur containing oil for 200 hours at lgOY.
Although component lB is preferably in the form of a
wire, component lB may have any shape provided it has a
portion thereof that is able to be eroded away
surficiently to open an electrical circuit to which
5 detector 20~ is electrically connected. Generally, the
depletion of anti-oxidants contained in extreme pressure
oils or lubricants marks the beginning of the creation
of negatively charged sulfur ions in the oil o~
lubricant.
Conductors 13 are made from an electrically
conductive material that is resistant to corrosive
attack from the oil or lubricant contained in cavity 8B
~nd to the elevated temperature to which the oil or
lubricant are subjected. Preferablyr conductors 13 are
15 ~nade from a metallic material having high iron cont~nt.
A means 15 for connecting each conductor 13 to an
electrical circuit is disposed Oll the end of each
conductor 13 adjacent the side oE gasket 14 facing away
from nut 3B. ,Although the means 15 ,for connecting
20 conductors 13 to an electrical circuit is shown in-
FI~URE 3 as a screw head, any means 15 that will
suitably electrically connect conductors 13 to an
electrical circuit may be used.
FIGURE 3 also shows a typical electrical
25 circ~it 19 to which detector 20B may be electrically
connected 'to provide an alarm signal when a --
predeter~ined amount of degradatlon of the oil or
lubricant in cavity 3B has been reached.
Circuit 19 has a resistor R2 in series with a
30 light emitting diode 17 which are both in parallel with
a voltage source 18 such as providea by a battery o a
motor vehicle for which the oil or lubricant is b,eing
monitored. Conductors 13 are electrically connected in
parallel to voltage source 18 by connecting means 15.
35 The resistance in ohms c,f resistor R2 is sufficiently
f` .,1
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greater than the resistance Rl in ohms of component lB
to preverlr diode 17 from being energized by voltage
sollrce 18 su~Eiciently to emit light when componen~ lB
has not been ero~ed away su~ficiently to open circuit
5 1.9. ~esistor R2 also has a resistance in ohms low
enough to enable diode 17 to be energized sufficiently
tc emit an amount of light suitable to provide a visual
indication to a viewer of diode 17 when component lB has
been eroded away sufficiently to create an opening in
10 circuit 19~ Thus circuit-l9 is normaliy closed when: ~.
compvnent lB has not eroded away sufficiently to crea~e
an open cixcuit l9, by being,
eroded ~w~y is able to cause volta~e source 18 to
energize d.iode 17 sufficiently to provide a visual
15 indication in the form of li~ht indicating that thP
chemical degradation of the sulfur reactive oi~ or
lubricant to which component lB is exposed has reached a
level predetermined by the particular mass selected for
component 1~.
Although the warnin~ signal is shown in FIGURE
3 in the form of a light emitting diode 17, the warning
signal may ~e an amp meter, or an audio device such as a
siren or other signal device that when energîzed by ~
voltage source when component lB is eroded away is able
25 to provide a warning signal that the chemical
degradation of the sulfur reactive oil or lubric~nt
being monitored has reached a level predetermined by the
particular mass selected for the.copper ion producing
component.
Although only two conductors 13 are shown in
FIGURE 3 as electrically connected by component lB~ any
number may be used that are electr.ically interconnected
in sllch a manner that their erosivn by sul~ur containing
acids arising from the degradation of the sulfur
35 reactive oil or lubricant being monitored is able to
. - 12. -
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energize an alarm signal providing a warning that the
chemical clegradation of the oil or lubricant has reached
a predetermined level.
Although it is preferred to use a simple
5 series-parallel e]ectrical circuit involving only
resistors such as circuit 19 in FIGURE 3 that is
normally closed up until the point where component lB
erodes away sufficiently to open the circuit and
energize an alarm signal,-any electxical circuit may be
10 used that enables an alarm signal to be energized upon
an open in the electrical circuit arising from the
erosion of a positively charged copper ion producing
component lexposed to the sulfur reactive oil vr
lubricant being monitored.
FIGURE 4 shows an embodiment of the apparatus
using the electrical circuit of ]FIGURE 3 in combination
with detector 20C which is substantially the same as
detector 20B previously described excepting that it is
made from a suitable electricall~y insulative mateial
20 rather than the electrically conductive material of
detector 20~ previously described. Detector 20C has a
body member ~C that extends through wall 6C of a housing
having a cavity 8C containing the sulfur reactive oil or
lubr;cant being monitored. Member 2C is threadingly
25 se5ured to wall 6C and has a nut 3C on one end thereof
outside of wall 6C and a flange 4C aisposed intermediate
body member 2C and nut 3C. Body member 2C, flange 4C
and nut 3'C are made from an electrically insulative
materal, such as a suitable electricaly insulating
30 plastic such as a polyamide having physical, temperature
and chemical resistance properties suitable to enable
detector 20C to be secured to wall 6C and remain secured
to wall 6C under the operating and temperature
conditions to which the housing containing the sulfur
35 reactive oil or lubricant is subjected. A pair oE
~Q1~7~
spaced-apart electrical conductors 13C extend through
nut 3Cr flange 4C and body member 2C into cavity 8C
enclosed by wall 6C such that the end oE conductors 13C
are exposed to the sulfur reactive oil or lubricant
5 being monitored. A positively charged copper ion
producing component lC having an electrical resistance
~1 electrically interconnects both conductors 13C as
previously descri~ed for the respective corresponding
components of detector 20B of FIGURE 3. Since_body
10 ~ember 2C, flange 4C and nut 3C are made from an
electricaliy insulative material, conductors 13C are not
required to be electrically insulated rom such
comp~nents such as is the situation in detector ~0~
which requires the use of an electrically insulative
15 gasket 14 and insulation material 1~.
Although it is preferred to use detectors of
the invention that can be threadingly secured to the
wall of a housing having a cavity containing the sulfur
reactive oil or lubricant being monitored for chemical
20 degradation, other means of releasably or fixedly
securing the æetector through an opening in the wall o~
the housing may be used where desired which are adaptea
where necessary to prevent leakage of the oil or
lubricant from the housing according to whether the oil
25 or lubricant is pressurized or unpressurized and also
permit the positively charged copper ion producing
component of the ~etector to be suitably immersed in the
sulfur re~ctive oil or lubricant being monitored.
