Note: Descriptions are shown in the official language in which they were submitted.
:~'2':~7~335
The present invention relates to ~uel pumps and,
more particularly, to fuel pumps having relief and/or vent
valves~
Wet motor fuel pumps of the gerotor type have not
heretofore used vent valves fuel vapor in that such pump when
rotating at its normal rate is not sufficiently efficient to
pump gases such as fuel vapors as compared to liquids such as
fuel gas. The generation of fuel vapors in any fuel pump is a
common occurrence. Gerotors meeting less than the tightest
tolerances on the tip clearances and also flatness and
parallelism are unable to self prims themselves against any
significant pressure head. But in a gerotor pump of the type
having a check valve in the pump outlet to prevent backflow
from the engine, such vapor pressures continue to build as the
motor continues to spin and generate heat. The little fluid
that may be introduced through the pump inlet is vaporized to
a level where the vapor pressure forces the fuel back out of
the inlet.
In the pumping of fuel in a wet motor gerotor pump
specific pressure criteria must be complied with to avold
excessive pressures in the closed fuel system for obvious
reasons. ~ccordingly, a pressure relief valve must be pro-
vided. The double function of venting vapor pressures until
liquid reaches the vent valve, and relieving fluid pressure in
excess of a predetermined limit in gerotor fuel pumps, have
heretofore been unknown.
The present invention recognizes the desirability of
combining the funct1ons of a vent valve with a pressure relief
valve to provide a single low cost valve usable with a gerotor
fuel pump, especiall~ a fusl pump of the wet motor type.
According to the present invention therefore there
is provided a fuel pump vent-relief valve for venting gases or
-- 1 -- ,~9
7~35
vapor under a pressure less than a fluid pressure and reliev-
ing said fluid pressure when in excess of a predetermined
pressure, said ven-t-relief valve comprising: a ball valve; a
tubular valve having a vent passage therethrough adapted to be
closed by said ball valve; a body having an inlet passage, an
outlet passage, and a valve bore therebetween, said valve bore
containing said ball valve and said tubular valve, said
tubular valve and said body cooperating to define a relief
passage between said inlet passage and said outlet passage;
first biasing means interposed said ball valve and said
tubular valve said first biasing means acting to bias said
ball valve towards said inlet passage and said tubular valve
towards said outlet passage, said ball valve adapted to co-
operate with said inlet passage to establish a vapor bypass
passage therebetween when said ball valve contacts said inlet
passage, and said tubular valve having a vent passage there-
through adapted to be closed by said ball valve; and second
biasing means interposed said tubular valve and said outlet
passage, said second biasing means for biasing said tubular
valve towards said inlet passage to close said relief passage
between said inlet passage and said outlet passage, whereby,
said vapor pressure is vented through said vapor bypass pas-
sage and said vent passage of said tubular valve until said
fuel pump develops said fluid pressure overcoming said first
biasing means to cause said ball valve to close said vent
passage and whereby fluid pressure is relieved when said
relief passage is opened when said fluid pressure exceeds a
predetermined relief pressure to urge said tubular valve to-
wards said outlet passage to open said relief passage.
Suitably said tubular valve encircles said ball valve. Pre-
ferably said tubular valve comprises an axially extending rib
means having slots therebetween establishing said relief
~ t~ 3~?
passage. More preferably said inlet passage is encircled by a
non-circular seat and said ball valve comprises a ball estab-
lishing said vapor bypass passage therebetween. Desirably
said non-circular valve seat is square. Suitably said non-
circular valve seat is an oblong having a width equal to the
diameter of said inlet passage and a length in excess thereof.
Desirably said first biasing means comprises gravitational
means cooperating with a preferred orientation of said valve
axis being in proximity to the vertical axis with regard to
the earth.
Thus, in accordance with the present invention, a
vent-relief valve is provided for venting trapped gases or
vapor from a fuel pump and relieving the fluid pressure when
in excess of a predetermined relief pressure. The vent-relief
valve includes a ball valve, a tubular valve having a vent
passage therethrough encircling the ball valve and adapted to
be closed thereby, and a valve body having an inlet passage,
an outlet passage, and a valve bore therebetween containing
both the ball valve and the tubular valve. The tubular valve
and the valve body define a normally closed relief passage
between the inlet passage and the outlet passage. A first
spring interposed between the ball valve and the tubular valve
biases the ball valve towards the inlet passage and the
tubular valve towards the outlet passage. The ball valve is
adapted to cooperate with the inlet passage to establish a
permanently ope~ vapor bypass passage, by the use of an
imperfect seat therebetween even when the ball valve contacts
the inlet passage. The tubular valve has a vent passage
therethrough adapted to be closed by the ball valve. ~ second
spring interposed between the tubular valve and the outlet
passage biases the tubular valve towards the inlet passage to
normally close the rel~ef passage. The vapor preSsure is
- 3 -
ven-ted through -the bypass passage and the vent passage until
the fluid pressure overcomes the first spring to move the ball
valve to close the vent passage. The fluid pressure is relie-
ved when the relief passage is opened by a predetermined fluid
pressure to move the tubular valve towards -the outlet passage.
In one embodiment of the present invention a ven-t
relief valve for a pump adapted to pump a fluid capable of
developing a vapor pressure, said pump further adapted to
operate under a starting condition wherein said vapor pressure
is less than a fluid pressure and also under a pump condition
wherein said fluid pressure is intermediate said vapor pres-
sure and a relief pressure, said vent-relief valve comprising:
valve body means having an inlet passage, an outlet passage,
and a valve bore means extending therebetween along a valve
axis, said valve bore means having an inlet end encircli.ng
said inlet passage and an outlet end encircling said outlet
passage, said valve body means further having a first valve
seal surface at said inlet end and a valve stop surface at
said outlet end; a first and a second valve means contained in
said valve bore means and movable therein along said valve
axis, said first valve means being movable between said inlet
and said second valve means, and said second valve means being
movable between said first valve seal surface and said valve
stop surface; said first valve means adapted to cooperated
with a first seat means encircling said inlet passage to
establish a vapor bypass passage therebetween when said first
valve means seats on sald first seat means; said second valve
means having a roof portion, a vent passage therethrough for
venting vapors communicated through said bypass passage, and a
second valve seal surface encircling said vent passage, said
first valve means adapted to cooperate with said second seal
surface to effect a first seal therewith; said second valve
7~3~
means further comprising a third valve seal surface encirc-
ling said first valve means and adapted to cooperate,d wi-th
said first valve seal surface to establish a second seal, said
second valve means and said valve means bore establishing a
normally closed relief passage therebetween from said second
seal to said outlet passage; first biasing means interposed
said first and second valve means and applying a first seating
bias therebetween adapted to establish said first valve seal
until said fluid pressure is obtained, said fluid pressure
then overcoming said first seating bias to move said first
valve means against said second valve means to close said vent
passage; and second biasing means interposed said valve body
and said second valve means and applying a second seating bias
therebetween to normally establish said second seal until said
fluid pressure attains a predetermined relief pressure, said
fluid pressure then overcoming said second seating bias to
move said second valve means toward said valve stop surface to
open said first seal and relieve said fluid pressure through
said inlet passage and said relief passage; whereby said first
and second valve means cooperate to vent said vapor pressure
~0
until said fluid pressure causes said first valve means to
close ~aid vent passage and to normally close said relief
passage until said fluid pressùre reaches said predetermined
relief pressure. Suitably said first biasing means comprises
gravitational means cooperating with a preferred orientation
of said valve axis being in proximity to the vertical axis
with regard to the earth.
Therefore the present invention provides an improved
wet motor pump.
The present invention also provides a fuel pump of
the foregoing type having~ a combined vent-relief valve.
The present invention again provides a fuel pump of
- 4a -
~"~ 71~:3~5
the foregoing -type wherein -the vent relief valve includes two
valve members that cooperate with each other in the same valve
bore.
The present invention further provides a vent-relief
valve of the foregoing ~ype wherein the first valve member
seats on an imperfect valve seat and establishes therebetween
a vent bypass passage, the first valve member being moved to
close a vent passage provided through the second member when
the pressure in the pump exceeds a fluid pre,ssure.
The present invention again provides a vent-relief
valve of the foregoing type wherein the second valve member
establishes a normally clos~d relief passage with the valve
bore and is moved to open the relief passage when tha fluid
pressure reaches a predetermined limit.
The present invention will be further illustrated by
way of the accompanying drawings whereln:-
Figure 1 is an end view of one embodiment of a wetmotor gerotor fuel pump having certain features provided in
accordance with the present inven-tion;
~ igure 2 is an axial cross-sectional view of the
gerotor fuel pump of Figure 1 taken along line 2-2 thereof;
Figure 3 is a transverse radial cross-sectional view
of the gerotor fuel pump of Figure 2 taken along line 3-3
thereof;
Figure 4 is a transverse radial cross-sectional
view of the gerotor fuel pump of Figure 2 taken along line 4-
~thereof;
Figure 5 is an enlarged and exaggerated view of
portions of an armature shaft and inner gerotor pump gear;
~ - ~b -
, .. ..
3~
F~gure 6 ts a cross-sectional vlew of the outlet houslng w~-th an
outlet check valve and vent valve of the gerotor fuel pump of Ftgure 1 taken
along llne ~-6 thereof;
Flgure 6A is a cross-~ect~onal v1ew of an 1mperfect valve seat and
ball valYe of the vent valve of Flgure 6 taken along 11ne 6A-5A thereof,
Ftgure 7 ls a vlew of the gerotor fuel pump of Ftgure 2 taken
along llne 7-7 thereof;
Ftgure B ts a fragmentary plan vlew of a portlon of Flgure 2
show1ng the orlentation of the outlet hous~ng by the use of an tndex~ng tab
postt~oned bet~een the two motor magnets;
Flgure ~ is an exploded vie~i~in perspective~ of the gerotor fuel
pump shown tn Ftyures 1 through 8;
Flgure 9A ls a perspect1ve v~ew of the coupllng arrangement of the
armature shaft dn~ the lnner gerotor pump gear of Flgures 1 througll 9;
o~
Flgure 9B 1s a perspective view of 3~ R7~e less preferable
a1ternatlve embodiment of the keeper of Figures 7 and 9;
F~gure 10 ~s a partlal sect~onal vte~ of a port10n of an alter-
nat~ve outlet houslng, showlng a vent-rellef valve and a bushtng for rota-
tably support~ng an end portlon of the armature shaft,
. F19ure 10A ls a perspect~ve vlew of portton~ of an alternate ver-
s~on of the support bushing and outlet houslng of F19ure 10 show~ng the slot
and kcy arrangement thereof for ltmttlng ctrcumferent1al rotat10n of the
bushing;
-Flgure 11 ~s a perspective vlew of a psp-off valve of the vent-
rellef valve shown 1n Flgure 10;
l~L~ 3351
F~QUre 12 1S a top v~ew of the alternate outlet houslng of F1gure
1~;
Flgure 13 ~s a bottom view of the lnternal conf~gurat~on of the
alternate out7et housing of F~gure 12;
F1gure 14 is a cross-sect~onal view through just the alternate
outlet hous~ng of F1gures 10~ 12, and 13 taken along line 14-14 of Flgure
12;
F~gure 15 is a vlew taken through just the outlet houslng of
F1gures lO, 12~ 13, and 14 taken alon~ 11ne 15-15 of Flgure 1~; and
lO . Flgure 16 ls an explod~d v1ew in perspect~ve of certa~n features
of the alternate outlet housing assembly, certaln parts thereof belng broken
away.
Wlth referencP now pr~marily to F~gures 2 and 9, there ls shown a
wet motor gerotor p~mp asse~bly or pump 10 for recelving a fluid such as
fuel from a source such as 2 fuel tank (not sho~:n) and dellver~ng
pressur1~ed flu1d to a ut11~at~on ~evice such as an lnternal combust~on
eng1ne ~not shown). The wet motor gerotor pump assembly or pu~p 10 includes
a tubular stepped case 12 generally enclos~ng an ~nlet and pump hous1ng 14,
algerotor pump assembly 16~ a motor ~lux r;ng 17, a pump outlet or port
and be~ng sealed aga1nst an outlet hous1ng 18 wlth an electrlc motor
assembly 20 supported between the lnlet an~ pump houslng 14 and the outlet
hous1ng 18.
The tu~ular stepped case 12 termlnates at one end 1n a seal~ng l~p
22 flanged lnwardly to seal agalnst an outwardly extend1ng annular shoulder
24 of the outl~t hous1ng 18. Towards ~ts other end~ the tubular stepped
case 12 ~ncludes an outer bore 26 generally def~n1ng a motor chamber 28~ a
7~35
pump bore 30 optionally ~ pped ~nwardly :Erc~n the outer kore 26 a-t ~n
a~ lar sho~llder 32 and
generally def~nln~ a pump chdmber 34, and an ~nlet bore 36 stepped 1nwardly
fro~ both the outer and pump bores 2~ and 30 and generally defin1ng an fnlet
chamber 38. The ~nlet.cham~er 38 i~ a~apted to be communlcated 1n a known
manner with a fuel source (not shown) such as by a known fluid coupl~ng,
condult and ~11ter (not shown).
Made of a one-p~ece d~ecast z1nc structure, the ~nlet ~nd pump
hous1ng 14 has a cyllndrlcal outer periphery 40 fitted ~nto the pump bore ~n
the pump chamber 34 of the tubular stepped case 12. At an ~nlet end
thereof, the lnlet and pump housing 14 termlnates ~n a tubular hub 42
protruding ~nto the ~nlet bore 3~ and inl~t chamber 38 of the tubular
stepped case 12 and also has a stepped bore 44 of a structure and function
to be descrlbed in greater detail hereinafter. The cyllndr~cal exterlor 45
of the tubular hub 42 ~s separated by an annular space ~6 from an enc1rcling
annular sprlng washer 48 hav~ng an inner diameter port~on 50 seated agalnst
an annular hub seat 52 protrudlng axially inwardly from the 1nterlor of the
tubular stepped case 12. The annular sprlny washer 48 also has an outer
dtameter portton 54 captured axlal7y and radlally ~n an annular counterbore
56 formed on the lnlet s~de 5B of the inlet and pump houslng 14 ~ust 1nboard
of the cylindrical outer perlphery 40 thereof.
Th~ electr1c motor assembly 20 includes an armature shaft 60
havlng an armature shaft lnlet end 62 and an arm~ture shaft outlet end 64,
each shaft end belng rot~tably supported by a respect1Ye tubular bushlng or
bearlng 66 and 68 sl~p-f1tted thereon and res11~ently supported by 0-rlnys
70 and 72~respectlYely~engag1ng a bore 74 ~n the lnlet and pump hous~ng 14
and ~ bore 76 1n the outlet hous~ng 1~. The tubular bushlng 66 15 lubr1-
cated and cooled by fuel in the ln1et chamh~r 38, and the tubular bush1ng 68
ls lubr~cated by flu~d fed through ax1al slots 75 sp~ce~ about the
per1phery of the bore 74. The armature sha~t 60 ls posit~oned generally
--7--
t7~335
along a central floh axis ~8 through -the wet motor gerotor pump assembly 10
and ls posit;oned therealong by a thrust ~ash~r lS2 belng actively against
the thrust washer seat 184 ~h~ct~ is part of th~ pump ~ou-tlet or p~rt plate
180 by means of
tlle m~gnetic attraction acting t~ttwe~n the magnets 240 an~ ~42 and the arma-
ture stack. The bearing 66 of the inlet is positioned by me~ns of a
shoulder 80
extend~ng outwardly from the tubul.lr bushing 6~ and an annular shoulder 82
extending 1nwardly from the tubular hub l~2 to thereby capture the 0-r~ng 70
therebetween.
Adapted to rotate ~n the motor chamber 28, the electrlc motor
assembly 20 includes an armature ~ made of a plural~ty of ar~ature windings
36 wound through a plural~ty of slotted armature laminat~ons ~not shown)
press f~tted on a knurled portion (not sho~!n) of the armature shaft 60. Each
armature winding 86 has respectlve flrst ~nd sec.ond ends term1nated 1n a
known manner at a co~nnutator ~8 a~apte~ to electrically and sl~dlngly engage
a pa1r of d1ametr~cally opposed commutator brushes 90 and ~2 electrlcally
coupled to respectlve cup-shaped ter~nals 91 and 93. The ~rushes ~0 and 92
are urged agalnst the commutator 8~ along d brush d1splacement axis 94 by a
respective f1rst and second brush spring 9fi ancl ~8.
Press f~tted on the knurled portlon of the armature shaft 60
ax~ally outboard the oppos1te ~nds of the armature laminatlons are a f1rst
and a se~ond end ftber 100 and 102, each havlng elght fingers 104 extending
rad~ally outwards from a fibrous central tubular hub 106 spaced equlangu-
larly thereabout, each flnger 104 having at its tlp an axlally extending tab
108 extend1ng ax1ally inwards towards the armature lam~nat1cns to provlde a
?~ stand o~f therefrom. The outward ax~al si~e of each f~nger 104 has a smooth
curved outer surface therealong so as to non-abras~vely engage and support
the end loops of the armature w~ndings ~6. The flbrous central tubular hub
106 of the end ftber 102 has an annular thrllst shoulder 110 extend1ng
radlally out~ards ~herefrom and terminates ax~ally in a pair of dr~ tangs
or dogs 112 and 114, best seen in Figure 9, in the form of dla~e-trically-
opposed arcuate sectlons extending axlally towards and lnto the inlet and
pump housin~
As may be better understood with reference to Flgures 2, 3, and g,
the inlet and pump houslng l~ has a counterbore il6 opening towards the
armature 84 and definlng a gerotor cavity 118 and also has a central Dore
120 therethrough. The counterbore llG, the gerotor cavi ty 118, and the
central bore 120 are concentric about an offset axis 1~2, best seen ln
~lgures 3 and 9, hav~ng a predetermined radial offset 124 from the central
ld flow axis 78 along a f~rst radial direction generally perpendicular to th
brush displacement axls 94. As may be better understood w~th reference to
Figures 2~ 4, and 9, an oblong (lepresslon 1~6 and an oblong aperture 128 are
prov1ded in a bottom surface 130 of the counterbore llfi and are dlsposed
generally concentrlcally about the central bore 120. As best seen ln Ftgure
C~ ~3i~
4, the inlet s1de 5& of the inlet and pump nousing 14ihas 2~-oblong inlet
depresslon 132 extending axlally there~n. At first the oblon~ inlet
depression 132
on the inlet slde 58 col~nunlcates with thè oblong aperture 128 in the
bottom sur~ace l30 of the counterbore li~ and a second oblong inlet
depresslon l36 on the ~nlet s1de 5a of the inlet an~ pump hous~ng 14 which
also ~ ~ ~h~
communicates wlth the entire ohlong aperture 12~ ~n the bottom ~ 13~.
~he flrst and second inlet depressions l3~ and 136 cooperate to proY1de
unpressurized fluid to the gerotor cavlty 118 tor hoth prlmlng the gerotor
pump assembly lfi and provid~ng fluid to ~e pressur1zed thereby.
Located in the gerotor cavlt~ 118 of the gerotor pump assembly 16
ar~ an ~nner pump gear 142 and ~n outer pump gear 144, shown only in Flgure
3~ Th~ 1nner and outer pump gears 142 and 144 have re$pectlve serles of
inner and outer pu~p teeth 154 and 156 and pump teeth spaces 158 and 160
1ntervening therebetween. The inner pump teeth 154 o~ the ~nner pump gear
142 ~e~ng formed to pumplng1y seal an~ engage the outer pump teeth 156 and
_~J_
3~35
teeth spaces of the outar pump gear 1~9 while the outer pump teeth 156 of
~he outer pump gear 144 are for~ed to pumDingly seal and engage the ~nner
pump teeth 154 and the t~eth spaces 1~ of t~le Inner punlp ~ear 1~2. The
outer pump gear 144 has a cylindr~cal external perlphery 1~2 that 1s sllp-
fitt~ngly rece~ved by and posltione~ ln the counterbore 1lb of the gerotor
cavlty 118. The ~nner pump gear 142 has a central ~ore 164 therethrough
whlch~ as may be better understood ~lith reference to F~gures 2 and 5, has a
tapered openlng 166 faclng the bottom surface 130 of the c~unterbore 116 of
the inlet and pump housing 14. The ~nternal d~ameter of the inner gear
c~ntral bore
164 is slightly greater (e.g., O.Q01 inches) than the external dia~eter of
the armature sh~ft 60 pass~ng ther~throu~h and the axi~l length of the lnner
gear central bore 164 is selected bo be comparatively short ~e.g.,
0.005 inches)
w~th respect tn the internal diameter th~reof sn as to allo~ the armature
shaft 60 to p~vot sl~ghtly end-to-end rela~ive to ~he lnner gear cen-tral
bore 164
1~ and thereby allow the 0-ring 70 to sel~align ~he ~rmatur~ shaft lnlet end
62 in the bore 74 of the tub~llar hu~ 42. Such self-aligning allows the
armature shaft 60 to eff ect small angles with respect to the central flow
axis 78, such angles increas~ng wlth increasing n~anufacturing and assembllng
toler~nces.
?0 Whlle thus allowed to ~elf-al19n relat~Ye to the lnner pu~p gear
1429 the armature shaft 60, as t)etter seen in Flgures 3 and 9A, nevertheless
dr~ves the 1nner pu~p gear 142. The 1nner pump year 142 has a palr of dr~-
ven tangs or dogs 172 an~ 174 e~ter,din~ radlally ~nwards therefrom into the
drtve coupl1ng cav1ty 170. Form1ng a drlYe coupllng 177, as best seen ~n
Figures 3 and ~A, each of the drlve tangs 112 and 114 have an ~ncluded angle
of approximately one hundred and eighteen degrees (118), and each of the
dr1Yen tangs 172 and 174 have ~.n ~ncluded angle of abou~ fi~ty-elght degrees
(~8). The four tangs 112, 114, 172 and 174 thereby hav~ng a total clrcu~-
ferentlal clearance of approx~mately e~ght ~egrees (~). Such clearance
allows suff1c~ent c1rcum~erentlal play to perm~t easy assembly of the dr~ve
7~;~S
coupling but ~l-t sl~ght axial ~isalignn-ent thereof to allo~Y the end--for-end
self-al7ynment of the armature shaft GO relat7v~ to tlle inner pump ~ear 142.
Complet7ns the g~rotor pump asser,lbly 16 are an annular pu~p
outlet or port pla-te 180 and a thrust washer 182 made of Teflon loaded
Ultem. The
pump outlet plate 180 has an annlllar tllrust surface 1~4 counterbored lnto
the outlet side 186 thereof and a bore 18~ thorethrol)gh of a tlla~eter suf-
ficient to allow th~ drive tangs 112 and 114 of tlle fibrous central tubular
hub 106 to freely pass therethroush h'ith a suitable clearance (e.g., 0.00~
1nches). The pump outlet plate 180 also has 2 cyl7ndrical outer perlphery
190 and an annular radial groove 192 extenaing lnboard therefrom, the
annular outer
peripheral surface 1SO belny rece1Yed in the outer bore 2G of the tubular
stepped case 12 and be~ng seated against th~ face of the annular shoulder 32
there1n, prov~ding both radial and axial positioning relative to the
motor flux
ring 17. The thrust washer 182 is pressed against the annular thrust sur-
face 184 of the pump outlet plate 180 by the annular thrust shoulder 110 of
the f1brous centr~l tubular hub 106. T~le thrust washer 182 has a pair of
dlametr~cally-oppose~ arcuate tangs or uogs 133a and 193b extend1ng radlally
inward to engage and be dri~en ~y the dogs 112 and 114 of the f1brous
central tubular hub 106.
On an axial s1de faclny the inner and outer pump gears 142 and
144~ the pump outlet plate 180 also has an ohlong depress10n lg6 and
outer aperture
generally match~n~. the shape ~nd pos~t~on of the oblon~ depress10n 126 and
the oblong aperture 128 ~n the bottom surface 130 of the counterbore 11G of
the gerotor caY1ty 118 of ~he inlet end pump hous~ng 14. To afford proper
pump pr~m1ny and other des1rable pumping characteristlcs, the oblong aper-
ture 128 and the oblong depression lS6 are com~unlcated through,
respect7vely, bores 120 and 188 bv appropr7ate rad7al slots 200 and 202, as
best seen 7n F1gures 2 and ~. Moreover, to prov7de a suitable outlet port
for flu~d pumped to a f~u1d pressur~ in tl-e ~erotor cavity 118, the
annular pu~,p
outlet p1ate 1~0 has the oblong outlet aperture 198 formed therethrough
and posi-
1 ~ q ~
t~oned and shaped to correspond hlth the oblong depress~on 126. To properly
positlon the pump outlet plate 1~0 circumferentlally ~lith respect to the
inlet and pump housing 14, a palr of locator pins 204 and 206 are aff~xed
thereto to extend ax~ally from an annular r~dial surface 20B to engage
suitable holes 205 and 207 through an anrlular rad~al surface 209 of the pump
outlet plate.
Pressure flutd from the oblon~ outlet aperture 198 of the pump
outlet
plate 180 ~s ~ulded therefrom and protected from the w~ndage effects of the
armature ~4 by a tunnel and magnet keeper device 210, best seèn ~n F~gures
7 and 9. The tunnel and magne~ keeper deYice 210 conslsts of a f~rst flow
channel or passage 211 shlelded from the anmature ~indage t~xtend~ng substan-
t~ally the entire axlal length of the motor chamb~r 28 between th~ pump
outlet plate 18n and the annular shoulder 24 of the outlet housing 18.
Shaped generally ~n the form o~ an invert~d staple, the tunnel and magnet
keeper dev~ce 210 has a central br~dge port~on 212 ~ounded by a pair of leg
port~ons 214 and 21~. The central hridge portion 212 has a sl~ghtly convex
shape, as seen from a po1nt external to the pump, to match the clrcular con-
tour t)f the periphery of the ar~ture ~4, and the pa1r of leg port~ons 214
flnd 216 extend radially outwards from the central bri~ge port10n 212 to seat
Dn an inner peripheral surface 218 of the cylindrical magnetic m~tDr flux
rtng 17. The flux rlng 17 also extends substant~ally the entire ax~al
length b~tween the pump outlet plate 180 and thc outwardly extendlng annular
shoultler 24 of the outlet hous1ng 18.
To allow suhstantially un~mpeded flcw of pressure flu~d ~rom
the oblong
outlet aperture 198 into the tunnel and magnet keeper deY~ce 210 whlle also
imparting a des~red clrcumferent~dl posltion to this devicP, the lnlet end
222 thereof 1s provlded with two ax~lly extendin~ protrus~ons 224 and 226
spaced rad1ally apart to proYlde a flu1d entrance 22B therebetween. The
axial protrus10n 224 te~inates in a butt end 230 abutting d~rectly agalnst
the annular radlal surface 2~ of the pump outlet plate 180. The ax~al
-12-
~d'~ 3~
protruslon 226 termlnates ln a stepped tab 232 hav~ng a butt end 232a
abutting agalnst thP c~lular radial surface 209 and a pin portion 232b e~Ytending
~nto the outlet slde o~ the hole 207 provlded to properly orlent the pump
outlet plate I80 wl-th the lnlet and pump housing 14 as aforementioned,
The leg port~ons 2I4 and 21~, of the tunnel and magnet keeper
devlce 210 cooperate ~lth a pair of tabs 234 and 236 extending circumferen-
tially outwards from the respective axlal protruslons 224 and 226 to pro-
perly position the palr of crescent shaped motor magnets 2~0 and 242 bot
c~rcumferentially and ax~ally wlth respect to the armature B4, As may be
I0 better understood wlth reference to F19ures 7, 8 and 9, each crescent shaped
motor magnet 240 and 242 ls bounded along its axlal length by a first and a
second set of juxtaposed ax1al sur,aces 240a, 240~, 242a and 242b, and each
motor magnet 240 and 242 ts bounded at its inlet ard outle$ ends by respec-
tlve end surfaces 240c~ 242c, 240d ~nd 242d.
In assembly, the tunnel and magnet keeper dev~ce 210 is flrst
inserted s~ that th~ pin portion 232b thereof is positioned ln the
locator hole 207 of the pump outlet plate 180. Thereafter, the crescent-
shaped motor magnets 240 and 242 are ~nserted so that the 2xial surfaces
~40a ~nd 242a respectlvel~ abut tne leg port~ons 214 and 2I6 ~nd the end
0 surfaces 240c and 242c abut the tahs 2~4 and 236. lo properly space the
motor magnets 240 and 242 fr~l the outlet port plate 180 and prov1de a
second axial channel 211a therebetween, a Y-shaped compress1On sprlng 246 ls
then lnserted between the second set of ~uxtaposed axlal surfaces 240b and
242b to urge the axlal surfaces 240a and 242a clrcumferentlally into
abutt~ng cont~ct w1th the leg portlons 214 and 21~. of th~ ltunnel and
magnet keeper device 210.
F1nally, the outlet housing 18 ls lnserted ~nto the tubular
stepped case 12. The clrcumRerential or~entation of the outlet hous~ng 18
h~ing determlned relative to the tunnel and magent keeper devlce 210, as
3~ best seen ln Flgure 8~ by an arcuate tab 2~8 extend1llg between the ax~al
-13-
793~
surfaces 240b antl 2~2b of the cres-ent s~aped motor magnets 240 and 242. A
pump out1et port or fitting 252 th.rough the outlet housing 1, is thereby
aligned
alon~ the same ax~al plane ~nters~ct~n~ -the center of the tunnel and magn~t
keeper devlce 210 an~ the center of the olltlet aperture 1~8 through the pump
outlet plate 1~0.
The forego~ng proper circumferential or~entat~on of the outlet
~ouslng 18 relat1vP to the tunne~.and magnet kceper deY~ce 21Q permits a
flow of pressurized fluid smcothly there~hrough directly from the outlet
aper-
ture 198, through the first f10~l passa~e 211~ to the pump outlet port 252 of
the outlet housin~ 1$~
It has been found throu~h experimental test results, under stan-
dard condit10ns, that the foregoin~ apparatus substant~ally improves pump
performance. Comp~red with wet pumps of slm~lar sk e and capacity, the
foregoing wet motor pump assembly provided the des~red fluid pressure at
lS substantlally 1ncreased flow rates wlth substantlally decreased armature
currents. For example, ln one typical appl~cat10n to a conventlonal
passenger car lnternal combust~on engine, flow rates were un~formly
~ncreased by at least three gallons per hour wh~le the corresponding arma-
ture currents were decreased at least twelve percent (12~).
Some portion of th1s improvement 1s attr1buted to merely provld~ng
the axlal ~1NW channel, such as $he magnet keeper 210a of the type shown ln
Flgure 9B. Such ~ keeper has a central bridqe portion 212a abutting
radially outwards aga~nst the flux rln~ 17 and bounded by a pa1r of leg por-
tions 214d and 216a open~ng radially ~nwards towards the armature 84.
However, such a keeper would ~llow the armature windage to ~nduce radlally
oriented hydraul~c curls ~n the flo~ channels 211~o 8ut such turbulence
would reduce the effective cross-sect~onal area of the axial flow channel
211b to a small portion of the ~ctual cross-sectioned area thereof. To
avoid su~h curls and turbulenc:e and substantially lncrease the effect~Ye
area, the tunnel and magnet keeper dev~ce 210 of the preferred embodlment
-14-
~4~3~
1s prov1ded so that the central br1tlge portlon 212 thereof sh1elds the flow
therethrough from the armdture wlnda~e. Sllould fllrther 1mprovements be
des~red to avo1d hydraulic curls indlJced ~1th an or1entatlon ln the channel
211 by the flow restr1ct10n 1mposetl by the circumferential width thereof
the channel 211 could be further subdiv1ded into subchannels of a plurality
of tubes or slots. Such subchannels ~oul~ proYi(le a laminar flow substan-
t1ally 1ncreas~ng the effective cross-sect10nal area of the tlow to the
actual cross-sectional area of the challnel.
As hest seen in Figures 1 and 6 the outlet housing 1~ made of 2
molded plast1c such as Ultem inclu~!es the pu~p outlet valve 250 with the
t~bu--
lar outlet port or fitting 252 adapted to be ooupled to an internal
co~busticn
engine. The tubular outlet fittin~ 2i~ has an internal outlet passage 251
hith a slotted seal 2~3 fitted Intr! ar~ outlet bore 254 to enclose a ball
valve 2~5 of a one-way check valve ~5fi therein. The outlet hous~ng l~ pro-
vides an annular seat 257 cooperating ~ith the ball valve 255 to provlde the
one-way check valve 256 preventing L~ackflow from the engine into the
pump. To allow normal flow from the pump 10 to the eng1ne9 t~e
tubular outlet
~1tt1ng 252 termlnates 1n four tapered prongs 25~ forming slots 259
therebetween the tapered prongs 258 normally restra1nlng the outward move-
ment of the ball valve 255 and the slots 259 allow1ng the fuel to flow out
therebetween. The angle formed by the tapered pron~s 25 1s such as to
cradle the ~all valve 255 so as t~ prevent oscillat~on of the ball at cer-
taln flow rates.
A further feature of the ~et ~otor pump asse~l)ly is a vapor
vent valve 260 prov1ded in the outlet hous1ng 1~ as best seen 1n F19ures 6
and 6A. The vapor vent valve 260 1s locate~ diametrically opposlte the
2i outlet valve 250, and 1ncludes a ball 2~2 enclosed in a valve bore 264 by a
tu~ular vent f1tt1ng 2~6 having a vent passage 268 therethrough and having
; an annular hub 270 seated aga~nst an annular seat1ng surface 272 of the
1~'7~33~
outlet housin~ 1~. A helical spring ~7~1 b1ases ehe ball ~G2 d~ay from a
shouldor 27fi enclrc~ing an annular lnternal hub 278 of the tubular vent
fltting 266 and towards an imperf~ct seal in th~ form of a square seat 280,
best seen in Fi~ure ~A, at the end of a vent ~ore 282 formed in the outlet
hous~ng 18, l~hen ~n contact ~it!l ti~e square ~o~t 2~0, t!le l~all 262 touches
the square seat 280 at only four points 2~4a, 2~4b, 2.~4c, and 2~4d, such
arrangement provi~ng four suitable bypass passages 286a, 2~6b, 28~c, and
286d. Wlth thls arrangement, a vapor pressure developed by the ~erotnr pump
assembly 16, especlally dur~ng self-priming thereof, is unloaded through the
bypass passages 28fia, 286b, 286c, and 2~6d unt11 liquid reaches the output
slde of the pumping elements and the vent bore 282. Thereafter, the fluid
pressure on the ball 2~2 w~ll overcorne the bias thereon by the helical
spring 274 to seat the ball 262 on the annular ~nternal hub ~7~ formed at
the ~nboard end of the tubular vent fitting 265, thereb~Y closing the vent
passage 268 and allowing normal pumping operat~on an~ outlet througll the
outlet port 252.
The square seat 280 in the foregoing vapor vent valve 250 may be
replaced by other sultable non-circular, or imperfect, valve seats lncluding,
for example, part1ally-circular vdlve seats as mlght be effected by a clr-
cular valve seat havlng axlally extending slots therethrough.
A further appl1cation of an lmDer~ect val~e seat is 1n comb1nation
w1th a vent-rel~ef valve 290 sho~:n molded lnto the alternate outlet houslng
19 ~n F1gures 10 and 11. As may be better understood with reference
thereto, a hall 292 ls enclosed ~n a bore 2~4 provided ln the outlet hous~ng
19, the bore 294 defln~ng therein a valve cham~er 2~5. One end of the bore
294 ~s in constant communlcat10n wl~h a vent-relief passage 2g6 prov1ded
through the end o~ the outlet^housing 1~, and the other end of the bore 294
ls suitably seeured, such as by ultrasonic welds9 to a ~alve seat member 298
hav~ng a central passage 300 therethrough~ln constant cornmunicat~on w~th the
motor chamber 28. The centrl~l passage 300 opens 1nto an oblong valve seat
-lfi -
~f~L~ S
~01 ln the form of an obton~ col!nterbore hay-i~ri a wldth equal to the
d~ameter of thc c.entral passa~e 30~ ~nd a lengtll twice thereof. When in
contact with the valve seat m~mber 298, the bk~ll 292 can contact
the oblong valve
seat 301 elth~r at t~Jn dlarnetr~cally opposite points ~f central~y located
thereon~ or ln ~ seml-circle linQ contact if shifted to elther ~xtreme slde
thereof. Elther way~ th~re ls ~ hyp2ss p~saq~ constantly open between the
~all 292 and the oblon~ valve seat 3n~.
Also located ln the valvP chamb~r 2~5 formed by the bore 2g4 and
the valve seat ~ember 29~ ls a tubular pop-~f~ or relief valve 302, 2 first
hel~cal sprlng 3Q4, a second helical spring 3~fi, and an O-ring 30~. One end
of the first helical spring 304 is biased against an annular shoulder
310 formed
1n the vent-relie~ passag~ 2~6, a~d t~e ~ r end of t~l~ first helical
spring 304
is biased aga1nst an annular top surface ~12 formed at the top of the pop-
off valve 302 and encircllng a centrcil vent passage 314 therethrough, The
hel~cal spring 304 blases the tubular pop-off valve 302 ~o nor~ally se~t and
seal a~a~nst the O-ring ~0~ the O-ring 30~ being normally seated on an
dnnular seat surface ~16 provlded ~n the valve seat me~b~r 29~ about the
oblong valve seat ~01 thereof. Wh~n the pop-off valve 302 is thus normally
urged aga1nst the O-ring 308 to seal against the annular seat surface ~16, a
normally=open bypass passage ~s ~stahllshe~ from the central passage 3~0 of
the val~e seat ~ember 298, thrDugh the central vent passage 314 of the pop-
off valve 3029 and the vent-rel~e~ pdssage 29~ of the outl~t hous~ng 19.
Thls vent bypass passage belng closed as wlll be descrlbed when the pump
assembly 10 produces a flu~d pressure ln excess of a predetermlned maxlmum
; 25 ventlng pressure in the fonm of a liquid at the l,all 292.
The tubuiar pop-off valve 3C2 also has an externally slotted tubu-
lar portlon 318 hav~ng a tube bore 320, at one end clear~ng the outer
diameter of the ball 292 and havlng an annular hub seat 322 dependlng inter-
nally from the other ~nd. One end of the second hellcal spring 306 ~s
3G seated about the annular hub seat 322, and the other end engages ~
peripheral surf~ce of the hall 2~2 to normally urge the ball 2~2 to seat on
the ohlong valve seat 301~ llow~ver, l~hen the fluld pressure exper1enced by
the pump 10 exceeds the max~muin vont~ng pressure, such excess pressure over-
comes the bias of the second helical sprin~ 305 on the ball 292 and r,'oves
the ball ~92 towards the annular hll~ seat 3~2, seat~n~ on the same when the
pump pressure exceeds the predetermlned maxlmum venting pressure. At pump
pressures bet~een the maximum vent~ng pressure and a predeterm~ned relief
pressure, the ball 292 closes the flu~ rassa~e het~een the central seat_
passage 300 and the vent-rel1ef passa~e 2~lfi.
To provide a rel~ef capab~lity or condit10n ~Ihen the pump
experiences a fluid pressure ln excess of thc pred~termined rell~f pr~ssure,
the axial ~eriphery ~24 of the pop-off valve ~02 ~s prov1ded with six ribs
~26a9 3~6b, 326c, 32fid9 32fie, an~ 3?6f, extending radially outwards ana
spaced equlangularly thereabout on the tube pnrt~on 318, the r~bs 326a
through 326~ also gu~d~ng and centrally pos~tionirlg the pop-n~f valve 302
with respect to the bore 2g4. Eacll of the axial ribs 326a through 326f ~5
cDntiguous with a respect~ve spar~r tab 328a through 328f upstand~ng a~lally
from and about the annular top surfac~ ~12 and ~hecentral vent passage 314
therethrough. The tabs 32~3athrQush 32~f are a~apted to abut a~a~nst and
space the rema~nder of the pop-off valve 302 ax~ally from an annular stop
surface 330 counterbored ln the outlet housin~ 1~ about the vent-relief
passage 296. The ribs 326a throu~l- 326f a~d the respect~ve tabs 328a
through 328f form passages or slots 332e through 332f ~herehetween spaced
equiangul~rly about the central periphery 324 of the opc~off valve 302. The
slots
332a through 332f cooperate w1th the vent-relief passage 29~ to contlnually
commun~cate the ent1re sp~ce b~tween the ~ore 294 and the axial periphery 324 ofthe pop-off valve 302 wlth the vent-re?ief passa~e 2~6. I~owever, t~lls space
~s not commun~cated wlth the central passa~e 30~ until the pump exper~ences
a fluld pressure ln excess of the relief pressure, such excess pressure then
overcomlng the seat~ng b1as of thc- first helical spring 304 against
the C-ring 308
-18-
~'7~3~3~
t~ ~her~by rlove the ~op-of~ valve 30~ ~Yay from tlle annular seat surFace 316
an(l t~lar~s the annlllar stop surface 330. ~uc!l excess punlp pressure thereby .
ur~es thePoP-off valve away from the O-ring 308 to unseat from the
annular seat sur-
face 316 thereby openin~ a passage through the slots 33~a tl~rough 332f frcm
~he c~-tral passage 300, between the bore 294, -the aYial peripllery
of ~le rop-off
val~e 302 through the slots 33?a tllrou~h 33Lf and out through the vent-
relief passage 2g6.
Further alternate features of the pump 10 as sllr)wn ln Figures 10
and lOA are alternate tubular bushin~s 340 and 340a the axial length of
whlch has a convex form or raised portlon ln the shape of an nut~ardly
extendin~ bo~l or crown 342 that contacts the bore 344 in the outlet housing
1& to allow a sl~ght erd-for-end self-ali~nment of the armature shaft 60.
To restraln the tubular bushing fro~ rotating in the bore 344 an anti-
rotatlon device is prov~ded ~n the fom of d slot an~ key arrangement 348
i5 wherein a slot 3q8a 1n the tubular bushing 340 is circ~nferentially
somewhat wider
and radlally somewhat deeper than a key 3~8b.
A further feature of thc het ~otor gerotor pump 10 is the util1~a-
tion of otherw1se existing structurc in tlle alternate outlet housin~ 19 ln
combination wlth addltional passages formed therein to cool and lubr kate
a portion oF the tubular bush~ng ~4~ bet~een the point of contact of the
ralsed portion 346 ~l~th the bore 344 and the roof 360 of the out1et hous~ng.
As may be better understood with reference to the outl~t housing 19 shown in
F1gures 10 through 16 a bearing lubrlcation and coollng system 350 ln the
fonm of a flow network 354 1s provlded between a ra~sed cap portion 352 a
cylindrical peripheral surfdce 8 of the commutator 88 the ~ore 3~4 and a
pa~r of bru-ch support ridges 356 and 358 for support~ng the bru_hes 90
and 92
respectively.
As best seen in Figure 127 the raised cap portion 352 supports the
outlet valve 250 and the vent-relief valve 290 hose fittin~, ard
includes the
_19_
33~
generally flat roof 360 s~p~orting the outlet port L5(1 and the vent-rellef
valve 290 hose fittillg, and furth(?r inclucles 2 pa~r ~f s;de ~alls 3~2 and
364, and a pa~r of curve~ end ~alls ~6 an~l ~fi~.
The fl~ network 354, ~hen vlewed ~n the transverse rad~al plane
` of Figure 13, ~s shaped generally ir. the 'orm of the Roman numeral X. I'~ore
particularly, tlle flo~ network ~54 i~cludes ,our ~ranclles 370, 372, 374, and
376, each in the shape of a dog 1~9 and edCh comr.unicating w1th the axial
length af the bore 3~,4 as well as an annu1ar recess 376 encircling a stop
hub 380 projecting into the bore 3~ fro~ the roof 3~Ø Each of ihe
~ranches 370 through 37G extends ax~ally along the ~)ore 344 to the Inner
surface 3~1 of the roof 360. Each includes a c1de wall branch port10n 370a~
372a, 374a, and 376~. Each suc~, ~ide wall hranch port~on is generally
parallel to one of the s1de w~lls ~6~ and 3~4, w1th the ~ide ~all branch
port~ons 370a and 372a generally spanr.ing the vent-rel~ef valve 2gO whlle
the s~de wall branch portlons 374~ and 37~;a genera71y span the outlet port
252. Each of the branches 370, ~72, 374~ and 376 also ~nclude a radtal
branch portlon 370b, 372b~ 374b, alld 376b, eac!l term~natin~ in a respect~ve
side wall branch portion w~th a respective radial slot 370c, ~72c~ 374c~ and
376c formed c~rcumferent~ally through a bore wall 382 prov~ding the bore
344.
The brush support rldges 35fi and ?.58 include an arcuate r~dge
crown or wall element 356a and 358a faclng radially lnward, the arcuate
r~dge crown 356a be1ng bounded by a pair of radial r~dge slde walls 35~b and
356c whlle the arcuate ridge crown wall 35~a is ~ounded by a patr of rad~al
r~dge s1de ~alls 358b and 358c, Each set of the radial ridge s~de wails
356b, 356c, 358b, and 3S8c are spaced rad~ally apart by an ~ncluded angle of
abou~ n~nety degrees (90~ and, together ~lth the1r respectlve arcuate rldge
crown walls 356a and 358a~ extend axially to an arcuate ridge wall counter-
bore 384 at a depth correspondlng with th~ axial w~dth of the co~ut~tor 88.
The arc~ate rldge crCwns and walls 356a and 3~8a are of a dica~eter
slightly
-20-
'7~3S
greater than that of the cnmmutators ~.8 to allow clearance therebeth~een for
~ppropriate brush con~utator 1nteraction. The bore 344 cor,~nences at the
depth of the arcuate rldge counter~ore 384 and extends axially to the ~nner
sid~ 361 of the roof 360. W~th the ~ore 344 startlng below lhe brush sup
port r,dges 356 and 358, there ~s an arcu~te opening of approximately ninety
degrees (90) between the radial ridg~ Side walls of the opposing brush
support
ridges 356 and 358. In other ~lords9 there is a circumfer~ntial gap of about
nlnety degrees (90) extendtng the aYidl l~ngth of the COnTnUtator 88 between
the ra~al ridge slde WA1l5 356b and 358b and a similar gap extends
circumr
ferent~ally between the radial ridge side walls
Assum~ng that the armature ~4 is energized to rotate in a coun-
terclockw1se dlrection as vle~wed in F~gure 139 the cyl~ndrical periphery
of the commutator ~8 viscously drags fluid therew~th, such fluid being
plcked up ~y the rotation o~ the con~nutator at the radial slots 376c and
372c
havlng, respectlvely, the radial ridge s~de ~alls 3S6c and 35~b and belng
delivcred or thrown o~f against tl-~ next radial ridge s1de ~/alls 358c and
356c~ respect1vely, of the radial slots 374c and 370c. The fluid picked
up at the
diametrlcdlly opposite radial rldge s1de walls 356c and 358b there~ore
experiences a h1gher veloc1ty than the flu~d ~m~acting and collectlng at the
dl2metrically OppOs~te radial rid~e side walls 356b and 358c. This
differenoe in
veloeit1es causes the fluld ln the rad~al slots 370c and 374c to
move slGwer and therefore be at a pr~ssure hlgher than the fluld at the
radial slots 372c and 376c. A similar pressure differential could
be effected by other structures such as a vane or other form of flow
res~stanee, the rldge walls ~n the present embodi~.ent servin3 a dual func-
t1On of support1ng the brushes whlle also prov1d~ng the necessary pressure
d1fferent1al.
In any event, the resulting pressure d~fferentlal created by the
drag forces of the co~mutator periphery 69 on the flu1d at the indicated
rad~al rldge s~de walls effects a pu~plng actlon of fluld ~n the radlal
~ 5
branch port~ons 370b and 374b. Such pumping action i5 axially outwards
towards the 1nner surface 361 of the roof, then r~ally inwards into the
annular recess 378, then axial1y about the tubular bushing 340,
then radially out-
wards from the annular recess 378, and finally back through the opposlng
radial branch portlons 372b and 37~1b. In other wor~s, the commutator
cylindrical peripheral sur~ace 89, the brush supp~rt ridges 356 and
35&, and the flow networ~ 354
establish two parallel pu~p~ng chambers or circuits separated by the co~-
- mutator 88 but jo1ned at the annul~r recess 3-/8. The pressure differentials
created by the dtfference in velocit~es at the indicated radial rldge side
walls provldes two insoming and two outnoins flows of fluid thereat~ both
flows combinlng to cool and lubrioate the tuhular bushin~ 340 and the bore
344. With such cool~ng and lubr~cation, the life of the upper tub~lar
bushing 340
has been fountl to be signi~cantly increased ov2r the llfe of the same
bearlng wlthout such lubrlcation an(l cool~n~ oreover, an acceptable
lubrication w~ll al50 occur by provi~in~ st a single c~rcu~t com-
munlcattng with the annular recess .~78 con~unicattn~ wtth the llpper end por-
tion of the tubular bushing 340 above the point its crcwn 342 contacts
the b~re 344.
Such lubr~cat10n woul~ be less than that provided by the dual parallel c1r-
cu1t shown. Also, a sl1glt flow c~ fluid mi~ht b~ provi~ed hy such a single
ZO circuit should the 1nternal structure by happenstanee provi~e a sufficient
pressure different1al betweer the inlet and thc outlet to the annular recess
378, without the benefit of add~t10nal pre S5 llre bu i ld1ng structures.
Although the best mode contemplated l-y the inventor ~or carry~ng
out the present 1nventton as of the filtng date hereof has been shown as
Z5 described here1n~ it ~llll be ap~arent to those sk~lled in the art that
suitable modtficat~ons, variat~ons, and equivalents may be r.lade wtthout
departlng from the scope of the tnventlon. Thts tnventlon ~s to be limited
solely by the terms o~ the claims a~p~nded t~ereto.
-22-
