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Патент USA US2405061

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July 30, 1946.
2,405,061
C. W: SHAW‘
PUME STRUCTURE
Filed Dec. 2, 1942
2 Sheets-Sheet 1
(a
I 22
(gé
1N VEN TOR
fzdrgyce
9/ Ame_
ATTORNEYS
July 30, 1946.
c. w. SHAW
PUMP STRUCTURE
Filed Dec. 2, 1942
2,405,061
v
2 Sheets-Sheet 2
.
INVENTOR
(‘Zara/70¢? W554 m
E-i-
@?éé
A TTORNE Y5.
2,405,061
Patented July 30, 1946
UNITED STATES PATENT OFFICE
2,405,061
PUMP STRUCTURE
Clarence W. Shaw, Grosse Pointe Woods, Mich,
assignor to Eaton Manufacturing Company,
Cleveland, Ohio, a corporation of Ohio
Application December 2, 1942, Serial No. 467,565
5 Claims.
(Cl. 103—-42)
2
1
having end walls cooperating with the end faces
thereof, one of the walls being movable toward
This invention relates to fluid pumps and par»
ticularly to pumps of the rotating positive dis
and from the other thereof and said other of said
placement type, the principal object being the
end walls having inlet and outlet ports leading
provision of a pump structure of this type of
therethrough to said rotors or gear-like elements,
and the outer of said gear-like elements is mov
able axially toward and away from the second
mentioned end wall in accordance with variations
in pressure on the discharge side of said pump
improved design and construction providing im~
proved pumping characteristics.
Objects of the invention include the provision
of a rotating pump of the positive displacement
type capable of maintaining a predetermined
pressure on the discharge side thereof within 10 whereby to provide for direct by-pass of fluid
between said inlet and said outlet without the
extremely close limits over a wide range of speeds;
necessity of passing through the gear-like ele
the provision of a pump of the type described
particularly adapted for supplying fuel under
ments; the provision of a pump structure as above
described in which the outer gear-like element is
pressure to internal combustion engines; the pro
vision of a pump of the type described which is 15 normally urged towards engagement with the
?xed wall of the housing through engagement
with the movable wall thereof but in which it is
freely movable axially between the ?xed wall and
particularly efficient in passing volumes of gas
therethrough which may become entrapped in the
liquid being pumped thereby; and the provision
of a pump of the type described in which the by
the movable wall whenever the movable wall is
passing of excess fluid between the discharge and 20 retracted under the force of the discharge pres
intake side of the pump is accomplished in- a
sure of the pump; and the provision of a pump
simple, accurate and efficient manner.
structure of the type described in which the by
Other objects of the invention include the pro
passing of ?uid between the inlet and outlet sides
vision of a rotating positive displacement type
of the pump for the purposes of controlling the
of pump including inner and outer gear-like ele 25 discharge pressure is accomplished in an easy and
ments rotating in a, surrounding casing and in
ef?cient manner.
which one side of the gear-like element is pro
Still further objects of the present invention is
vided with a cooperating wall movable toward
the provision of a pump structure as above de
and from the same to provide for by~passing
scribed in which a ?lter or strainer is incorpo
fluid between the inlet and outlet sides of the 3 l. rated in the pump in a simple and ef?cient man
pump to maintain a predetermined pressure, the
ner; and the provision of“ a pump structure as
wall being mounted for movement axially on a
above described in which a ?lter or strainer of
rotating part whereby to eliminate the presence
relatively large surface area is incorporated with
of static friction opposing this pressure control
. in the pump.
ling movement; the provision of a pump of the
The above being among the objects of the pres
type described in which the discharge pressure of
ent invention, the same consists in certain novel
the pump acting on one face of the movable wall
thereof is limited to a de?nite area of such wall
features of construction and combinations of
parts to be hereinafter described with reference
and the suction pressure of the pump is applied
to the entire opposite face thereof; the provision
at
of a pump structure as above described in which
the movable wall is formed for direct equalization
between the suction pressure of the pump on one
face thereof and the entire opposite face of the
wall; the provision of a pump structure as above
described in which the suction pressure of the
pump is substantially atmospheric; and the pro
vision of a pump structure of the type described
in which the movable wall is provided with novel
means for preventing its rotation upon its ro 50
tatable support.
Further objects of the present invention include
the provision of a pump structure including in~
ternal and external inter-meshing gear-like
pumping elements and a cooperating housing
to the accompanying drawings, and then claimed,
having the above and other objects in view.
In the accompanying drawings which illustrate
suitable embodiments of the present invention
and in which like numerals refer to like parts
throughout the several different views,
Fig, 1 is a vertical sectional view taken axially
through a pump structure embodying certain fea
tures of the present invention;
Fig. 2 is a vertical sectional view taken trans
versely of the pump structure shown in Fig. 1 as
on the line 2—2 thereof;
Fig. 3 is a vertical sectional view taken trans
versely of the pump structure shown in Fig. 1
as on the line 3——3 thereof;
Fig. 4 is a fragmentary, vertical sectional view
2,405,061
3
4
.
taken transversely of the pump structure shown
portion 28 in suitable bearings 33 carried thereby
in Fig. l as on the line 4-4 thereof;
and projects into the chamber formed within the
Fig. 5 is a fragmentary, horizontal sectional
cap 32. The righthand face of the main body
view taken on the line 5~—5 of Fig. 4 to better
portion 28 is disposed perpendicular to the axis
illustrate the means employed for preventing the 5 of rotation of the shaft 32 and the inner rotor 20
movable end wall from rotating with its support
is mounted on the shaft 32 in substantial contact
ing shaft;
with the righthand face of the housing 28. Any
Fig. 6 is a fragmentary view of a, portion of the
suitable means such as a key 34 may be pro
construction illustrated in Fig. l to show the
vided between the shaft 32 and the inner rotor 20
position of the movable end wall and the outer
to constrain the two for equal rotation with each
rotor under actual pumping conditions;
other. Preferably some means is provided to lock
Fig. 7 is a vertical sectional view taken axially
the inner rotor against outward movement on the
through a modi?ed form of pump structure;
shaft 22, and a snap ring 35 partially received in
Figs. 8 and 9 are vertical sectional views taken
a complementary peripheral groove in the shaft
transversely of the pump structure shown in Fig. 15 32 and abutting the righthand face of the rotor
'7 as on the line 8-8 and 9-—9, respectively, there
2:3 is shown in Fig. 1 for this purpose. The cap
of;
member 36 receives therein a wear ring or bush
Fig. 10 is a view similar to Fig. '7 but showing
ing 36 in transverse alignment with the inner
a modi?ed form of construction;
rotor 20 and within which the outer rotor 22 is
Fig. 11 is a vertical sectional view taken trans
rotatably received. As is evident from an inspec
versely of the pump structure shown in Fig. 10 20 tion of Figs. 2 and 3 the ring at‘ is eccentric to the
as on the line H-H thereof; and,
axis of the shaft 32 so as to position the rotors 20
Fig. 12 is a fragmentary, vertical sectional view
and ‘22 in the proper relation with respect to each
taken axially through a pump structure of the
other as indicated in Fig. 3.
general type shown in the preceding views and
The righthand face of the main body portion
25
illustrating a modi?ed form of construction for
as best brought out in Fig. 2 is provided with
preventing rotation of the movable wall with re
an intake port 38 and an outlet port 40, these
spect to its rotating support.
ports being, of segmental conformation and ex
In the broader aspects the present invention is
tending approximately circumferentially with
capable of use in connection with various types
of rotatable pumps of the positive displacement 30 respect to the axis of the shaft 32 in overlapping
or encompassing relation to the space exposed at
type and where the language of the claims so per
one end of the rotors 20 and 22 between the teeth
mits they are to be interpreted in this broad
thereof and each at one side of a plane including
sense. The invention is, however, particularly
the axis of the shaft 32 and passing centrally
adapted for use in connection with those types of
through the point of full mesh of the rotors.
35
positive displacement rotary pumps that include
They approach each other relatively closely at
inner and outer members having inter-engage
able tooth-like elements. One such type of pump
is
illustrated in United States
Patent
No.
the point of full mesh where the teeth of the in
ner and outer rotors completely engage one an
other and are spaced from each other to a great
1,682,563, issued August 28, 1928 to Myron F. Hill
40 er extent at their opposite ends where such teeth
on Internal rotors, and, accordingly, such type
are spaced from each other by a maximum dis
of pump structure is illustrated in the drawings
tance, The inlet port 38 leads into an intake
by way of explanation. Accordingly, in each of
the pumps shown in the drawings there is an in
ner rotor 29 and an outer rotor 22, each of these
rotors having tooth-like projections 24 and 26,
passage 42 within the main body portion 28 from
which an opening 44 leads to an exterior face of
the main body portion 28. Such opening may be
threaded for reception of an intake pipe or tube
such as 45. The outlet port 40 is similarly con
other, The inner rotor is mounted eccentrically
nected to a discharge passage 48 which com
to but on an axis parallel with the axis of rotation
municates with an opening 50 leading to an ex
of the outer rotor, this eccentricity being such 50 terior face of the main body portion 28 and which
that at one point in the circumference of the
may be threaded for reception of a discharge pipe
respectively, which teeth intermesh with one an
pumping chamber which lies in the plane includ
or tube such as 52.
ing the axes of rotation of the rotors 20 and 22
The shaft 32 projects to the right beyond the
the teeth of the rotors completely engage one an
inner rotor 29 and rotatably mounted upon such
other and a tooth of one substantially complete 55
projecting end and within the cap member 30 is a
ly ?lls the space between the teeth of the other.
plate member 54 of an outside diameter substan
The outer rotor has one more tooth 26 than the
tially equal to the outside diameter of the outer
number of teeth 24 of the inner rotor, the ar
rotor 22. The lefthand face of the plate member
rangement and design of the rotors being such
54 is flat and is constantly urged toward the left
that the teeth 24 and 26 are at all times in sub 60
into contacting relationship with respect to the
stantial engagement with one another. Thus
corresponding faces of the inner and outer rotors
from the point of full engagement of the teeth
20 and 22, respectively, by means of a coil spring
with one another when there is substantially no
56 which is maintained under compression be
space between them the teeth, during rotation of
tween the plate member 54 and the end wall of
the rotors, ?rst recede from one another and then 65 the cap member 30. The actual pumping cham
approach one another during each revolution of
ber is thus formed between the righthand end of
the rotors to provide variable volume chambers
the main body portion 28 and the movable plate
through which the pumping effect is obtained.
member 54 within the wear ring 36, and the plate
In the construction illustrated in Figs. 1 to 6,
member 54 thus forms a movable wall for this
inclusive, the housing for the pump comprises a 70 pumping chamber which is capable of moving
main body portion 23 inthe form of a casting
having a flat righthand face, and a cap member
3i) suitably mounted and piloted on the righthand
end thereof as viewed in Fig. l. A shaft 32 is
rotatably mounted centrally of the main body 75
axially of the shaft 32 against the force of the
spring 55 in response to variations of pressure
in the pumping chamber to maintain the dis
charge pressure substantially constant.
This general type of construction, that is one
2,405,061
5
which employs a spring pressed plate to form a
movable wall for one side of a pumping chamber
is in itself broadly old, but in constructions as
heretofore suggested I have found that it is im
possible to accurately control the discharge pres
sure within the narrow limits required, for in
stance, in supplying fuel to internal combustion
engines, for the reason that when the pump is
driven at high speed the discharge pressure is
built up beyond permissible limits. The construc
tion shown involves certain departures from the
prior. art along this general line through the me
dium of which the discharge pressures may be
6
speeds is that in all prior constructions that I am
aware of the discharge pressure of the pump
acted over substantially one-half the area of the
movable wall and the suction pressure acted over
the remaining half thereof, the tendency of the
two pressures thus being to cook the plate rela
tive to its guiding means thereby increasing the
static friction which it was necessary to overcome
before movement of the plate or movable end wall
could occur in response to pressures existing in
the discharge side of the pump. In accordance
with the present invention such plate or movable
end wall is either cut away or apertured on the
suction side of the pumping element or elements
gardless of the speed of the pump and these will 15 so as to transmit the suction pressure on the
pump to the back face of the movable plate or
now be discussed. One reason why the pressures
end wall. This feature, therefore, effects an
in the prior art pumps of this general type can
equalization of the suction pressure acting on the
not be accurately controlled is that the mova
operative face of the movable end wall with the
ble wall was conventionally supported on ?xed
pins or the like between which and the movable 20 pressure existing behind it and thus eliminates
any pressure differential between the two opposite
wall static friction necessarily existed. In order
maintained within the required tolerances re
to overcome this static friction in order to ad»
just itself to variations in pressure of the dis
charge side of the ‘pump in an attempt to main
tain a constant pressure the movable wall neces
sarily was required to overcome the static friction
between it and its guiding means. The result was
sides of the plate or movable end wall over that
area thereof subject to the suction pressure of
the pump and on the operative face thereof.
In the construction illustrated in Figs. 1 to 6,
25
inclusive, the end wall 54 is provided with a slot
62 for the above described purposes, the slot 62
opening onto the adjacent marginal faces of the
that when the speed of the pump increased and
inner and outer rotors 20 and 22, respectively, at
the volume pumped therefor increased, the dis~
charge pressure was required to build up to an 30 that point in the position of rotation thereof
which is subjected to the suction pressures exist
undesirable degree before it could overcome such
ing in the pump, Thus it will be appreciated that
static friction and cause the movable wall to
all of the space within the cap 30 back of the plate
properly respond in accordance therewith. Like
5-5, or to the right thereof as viewed in Fig. 1, is
wise when the speed of the pump was decreased
and the volume pumped thereby correspondingly 36 subjected to the suction pressure of the pump and,
therefore, the entire rear face of the plate mem
decreased the discharge pressure would drop‘ be
ber or movable wall 54 is subject to such suction
low a desired minimum ?gure before the forces
pressure. In this connection it wili be readily
acting on the movable wall could overcome the
appreciated by those skilled in the art that in
static friction and allow the movable wall to move
to accommodate such change in volume.
40 many cases and perhaps the most cases, depend
ing upon the position of the supply point from
In the present case, the movable wall in being
which the pump draws its liquid to be pumped,
mounted upon the shaft 32 is mounted upon a
the pressure acting on the rear face of the plate
rotating part so that no static friction exists
54 will be atmospheric pressure or substantially
between it and the shaft. Thus the static fric
tion which caused the trouble in conventional 45 such pressure. In any event the pressure which
exists on the back face of the movable wall of
constructions is eliminated in this construction
plate member 54 will remain substantially conin this respect. The only static friction necessary
'stant throughout the entire operation of the
to be overcome .in the pump shown in Figs. 1 to 6,
pu'itip. As a result of the above described con
inclusive, is that in the connection between the
movable wall 54 and the cap 30 for maintaining 60 struction the only force effective on the operative
face of the plate member or movable wall 54 is
the movable wail against relative rotation with
the discharge pressure of the pump and this is
respect to the housing. This means, as illustrated
aided by the suction pressure of the pump which
best in Figs. ‘4 and 5, consists of a pin 58 secured
exists on an equivalent area from the back face
in the movable wall or plate member 54 in parallel
relation with respect to the axis of the shaft 32 55 thereof, in opposition to the force of the spring 56.
With the above described construction and un
and projecting to the right therefrom as viewed
less compensated for, the center of pressure act
in Fig. 5. The cap member 30 is provided with a
ing on the plate or movable Wall member 54 would
hollow boss 60 within which the pin 58 is axially
still be concentrated on the plate or movable end
loosely slidably received. It will be appreciated
that, of course, the amount of static friction 60 wall member 54 on one side of the axis of the
shaft 32 and would still have a tendency to cause
which is required to be overcome to eifect move
the plate or movable end wall 54 to become cooked
ment of the pin 58 within the hollow boss 60 is
on the shaft. This possible disadvantage is over
extremely small and offers no material resistance
come in accordance with a further phase of the
to axial movement of the movable wall for plate
member 54 in response to changes in pressure 65 present invention. According to this later-men
tioned phase the spring 56 is so’ located with re
acting upon the same. It will be noted that the
spect to the plate or movable end wall member
periphery of the movable wall or plate member
54 that it acts centrally of the center of pressure
54 is spaced from the inner walls of cap member
of the discharge side of the pump on the plate
30 so that no static resistance can be set up at this
point which would interfere with the free axial 70 or movable end wall 54. In other words and as
best brought out in Fig. 1 the spring 56 is not
movement of the plate member 54.
concentric with the shaft 32 but is arranged with
Another reason why rotor pumps of the prior
its axis radially offset from the axis of the shaft
art employing a spring pressed end wall were not
32 toward the discharge side of the pump, the
able to accurately control the discharge pressure
of the pumps over a relatively wide range of 76 amount of offset being ‘such that the center of
7
2,405,061
pressure of the spring 56 and the center of pres
sure of the discharge side of the pump on the
plate member 54 are substantially coincident with
one another. To maintain the spring 56 in such
positionv the plate 54 is provided on its back face
with an outstanding boss portion 54, best brought
out in Fig. 4, which is disposed at the desired
eccentricity and direction of offset with respect to
the axis of the shaft 32 for the spring 56. The
8
a direct passage is provided between the outer
rotor and the main body portion 28 between the
inlet port 38 and the outlet port 40 around the
exterior of the inner rotor 20 through which the
liquid may ?ow or by-pass to maintain a con
stant discharge pressure. This feature is very
important inasmuch as in the prior types of
pumps where the outer rotor is not capable of
following the movement of the plate member
closed end wall portion of the cup-shaped cover 10 and where, for instance, the pump is intended to
35, is likewise offset from the axis of the shaft 32
maintain a constant pressure of five pounds per
so that the spring 56 in seating against the end
square inch gage, as the speed of rotation of the
wall thereof will be arranged at the desired eccen
pump is increased the pressure increases up to as
tricity with respect to the axis of the shaft 32.
much as ?fteen pounds per square inch solely
Thus the pressure of the spring 56 and the dis 15 because of the resistance to flow of the liquid
charge pressure of the pump on the opposite face
between the two pumping elements. With the
of the plate member 54 are balanced so as to
present construction and because such Icy-passed
eliminate any cocking tendency of the plate mem
liquid is not forced to flow through the pumping
ber 54 of the shaft 32. The result is that the plate
elements but is provided with a free and direct
member 54 is freely movable on the shaft 32 and
path of ?ow between the inlet and outlet sides of
being substantially free of any static friction in
the pump, it has been found that the discharge
its axial movement is free to move in response to
extremely slight variations of pressure on the dis
charge side of the pump to maintain such pres~
sure constant. The sensitivity of the plate mem
ber 54 to changes in pressure on the discharge
side of the pump is, of course, increased if the
plate member 54 is constructed from a light metal
pressure of the pump may be maintained ex
tremely close to the desired maximum pressure
for which the pump is adjusted even under those
conditions where pumps designed according to
the prior art as above described build up two or
three times the desired pressure.
The above described pump may, of course, be
such as aluminum or magnesium or suitable alloys
mounted and driven in any suitable manner. In
thereof. This is preferably done. In such case 30 the particular construction shown the lefthand
the plate member 54 has less inertia to be over
end of the main body portion 28 is provided with
come in effecting movement thereof than where
a flat face 10 arranged perpendicularly with re
constructed of a heavier metal as will be appre
spect to the axis of the shaft 32 and is centrally
ciated by those skilled in the art.
provided with an annular pilot portion 12. Ac
It will be noted from an inspection of Figs. 35 cordingly, this pump is adapted to be received
1 and 6 that the inside diameter of the wear ring
upon a ?at face provided upon the crankcase or
or bushing 35 is less than the inside diameter of
other structural part of an internal combustion
the cap member 30 immediately to the right
engine with the pilot portion T2 closely ?tting an
thereof. Accordingly, it is possible for the outer
opening provided therein for properly locating it
rotor 22 to move to the right with the plate mem 40 on such face. The shaft 32 may, of course, be
ber 54 as the latter recedes under increased pres~
sure within the pump chamber and this actually
and desirably occurs as indicated in Fig. 6 which
illustrates the plate member in receded position.
This movement of the outer rotor 22 may be
caused by the fact that its right-hand face be
ing in ?at contacting relation with respect tojthe
operative face of the plate member 54 is sealed
against the flow of liquid under the discharge
pressure in the pump between them, while its
lefthand face is at least partially exposed to the
discharge pressure of the pump in the discharge
port 4-0. Whatever the reason, the outer rotor
22 does follow the movement of the plate 54 in
the latter’s movement toward or from the op
posed face of the inner rotor 20, in response to
variations in the discharge pressure of the pump.
The fact that the outer rotor 22 follows the
movement of the plate 54 is important for the fol
lowing reasons. If this movement did not occur,
then as the plate member 54 receded from the
rotors under an increased pressure and in order to
permit a larger volume of liquid to be bypassed
between the inlet and outlet sides of the rotors
in an attempt to maintain a constant discharge
pressure, it would require the by-passed liquid
to flow axially through the length of the pump
before it could be by-passed to the opposite side
of the rotors. This ?ow of the liquid axially
through the length of the pump under such cir
cumstances is not required where the outer rotor
follows the movement of the plate member 54 in
accordance with the present invention as in such
case as soon as the outer rotor moves away from
connected in any suitable manner to a rotating
part of such engine but in the particular con
struction shown the lefthand end of the shaft
32 is hollow and its outer end portion is interiorly
provided with axially parallel serrations 14. A
stub shaft 76 provided exteriorly with axially
parallel serrations 78 has one end thereof re
ceived within the end of the shaft 32 with the
serrations 18 thereof inter?tting with the serra~
tions 74 of the shaft 32. To maintain the stub
shaft 16 against axial movement with respect to
the shaft 32 a snap ring 80 is partially received
within a groove formed circumferentially of the
stub shaft 16 in the outer portions of the serra
tions 18 thereof and abuts against the outer end
of the shaft 32. A similar Snap ring 82 partially
received within a groove formed at the right
hand or inner end of the stub shaft 16 bears
against the inner ends of the serrations 14 of
the shaft 32 to lock the stub shaft 15 against out
ward movement with respect to the shaft 32'. A
suitable hollow drive shaft (not shown) having
internal serrations corresponding to the serra
tions '14 of the shaft 32 may envelope the outer
end of the stub shaft it so that the driving force
may be transmitted therefrom to the stub shaft
16 and from the stub shaft 16 to the shaft 32.
The fit between the serrations 14 and 18 and also
preferably between the serrations 18 and those
of the driving shaft above explained but not
shown, is sufficiently loose to permit a limited
amount of universal movement of the stub shaft
16 in the shaft 32 and also in the drive shaft so
as to eliminate the necessity of aligning the shaft
the cooperating face of the main body portion 28, 75 32 with the drive shaft with absolute accuracy.
2,405,061
In order to prevent the possibility of fuel es
caping along the shaft 32 and into the crankcase
or other part of the internal combustion engine
where the pump is mounted directly upon the
same, the lefthand face of the main body por
tion 28 is provided with a recess 84 around the
corresponding end of the shaft 32 and within
which a sealing device 85 is pressed. The recess
04 is provided with a smaller extension inwardly
of the sealing device 85 forming a pocket 86
between the outer bearing 33 and the sealing de
vice and this pocket is connected by a passage 81
with the suction passage 42 so as to permit a
small amount of the pumped liquid to circulate
over the bearing 33 for lubrication and any liquid
that is pumped between the shaft 32 and the
outer bearing 33 will be drawn back into the
pump, thus preventing any liquid from ?nding its
way along the shaft 32 into the engine.
It will be appreciated from the foregoing de 20
scription and explanation that in accordance
with the present invention certain improvements
have been incorporated in a pump of the general
type described which overcomes disadvantages in
similar pumps constructed in accordance with
the prior art and that as a result of such im
provements a pump having improved operating
characteristics is provided.
Invthe construction illustrated in Figs. '7, 8, and
9 the main body portion 28a and the cap mem
ber 30a correspond with the main body portion
20 and cap member 30 of the previously described
construction. Likewise the shaft 32a and the
inner and outer rotors 20a and 22a, respectively,
correspond with the shaft 32 and inner and outer
rotors 40 and 22 of the previously described con
struction. The cap member 30a in this case in
stead of terminating at its transverse 0r end wall
as in the ?rst construction has its side walls ex
tended therebeyond and the outer ends of the
same are closed by a sheet metal cap 90 which
is secured to the cap member 30a by means of
a screw 02 threaded into an outwardly projecting
boss 04 formed on the transverse wall of the cap
member 30a. An inlet passage 96 is provided
through such side wall extension and is inter
nally threaded for reception of an intake pipe
or tube 98. The sheet metal cap 90 is provided
with an inwardly projecting central boss portion
I00 and the boss 94 is enlarged near its base and
between these two portions a cylindrical screen
I02 is mounted, the ends having a close ?t with
such portions. A passage I04 is provided through
10
32a and collaborates with‘ the plate 54a in sub
stantially the same manner as the spring 56 co
operates with the plate 54 in the previously de
scribed construction. In the construction illus
trated in Figs. '7, 8, and 9 no wear ring'such as
the wear ring 36 in the previously described con
struction is provided but instead the outer rotor
22a has bearing directly in the cap member 30a
and is capable of moving axially therein with the
plate member'54a in the same general manner
as the equivalent parts in the previously described
construction.
_
It will be appreciated that in the construction
illustrated in Figs. '7, 8, and 9 the liquid flowing
into the pump is admitted to one side of the rotors
20a and 22a while the main body portion is pro
vided with a discharge port Ma on the opposite
side of the rotors, the port 40a being connected
to a discharge passage 48a which leads to the ex
terior face of the main body portion 28a in the
same general manner as the discharge passage
48 in the previously described construction. Ac
cordingly, the liquid being uinped must flow ax
ially through the full width" f the rotors in pass
ing through the pump and, unless otherwise taken
care of, the advantages described in‘ connection
with the ?rst described structure in being able
to by-pass liquid between the intake and dis-v
charge sides of the pump without flowing through
the rotors would not be realized. To obtain this
same advantage the main body portion 20a is
provided with a port 38a of substantially the same
shape and contour as the inlet port 38 of the
previously described construction but, of course,
': in this case such inlet port does not lead to the
exterior face of the housing 28a. The only func
tion of the port 38a is when the outer rotor 22a
moves axially with the plate member 54a away
from the coacting face of the main body portion
28a upon increase in volume ofthe liquid being
pumped, liquid may be by-passed directly be
tween the passage 38a and the discharge port 40a
in exactly the same manner as in the previously
described construction and without necessitating
such liquid flowing through the length of the ro
tors. The only volume of liquid that will ?ow
axially through the length of the rotors will be
that actually discharged from the pump. Thus
with the construction illustrated in Figs. '7, 8, and
9 the same lay-passing effect as in the previously
described construction is obtained.
In the construction illustrated in Figs. '7, 8, and
9 the outer end of the shaft 32a is sealed against
leakage of the fluid being pumped by means of
the transverse wall of the cap member 30a from
a conventional type of seal Ill] and a drainage
the space within the screen I02 so that the liquid 55 passage IIZ which connects the bearing for the
?owing through the inlet passage 95 must flow
shaft 32a in the main body portion .280. with the
through the screen I02 before it may ?ow through
passage 38a which is, of course, under the suc
the passage I04 to the space within the cap mem
tion pressure of the pump and which, therefore,
ber 30a to the right of the rotors 20a and 22a.
serves the same purpose as the passage 87 in the
The screen I02 is of such ?neness as to ?lter out
?rst described construction. foreign particles of objectionable size from the
It may also be noted that in the construction
fluid being pumped.
‘
'
illustrated in Figs. '7, 8, and 9 the inner end of the
Between the rotors 20a and 22a and the trans
shaft 32a is reduced in diameter and that the
verse wall of the cap member 30a a plate member 65 plate member 54a is rotatably mounted upon this
54a, corresponding to the plate member 54 in the
previously described construction, is provided,
but in this case instead of providing an opening
such as 62 ‘in the previously described plate on
the ‘suction side thereof, the same side of the
plate is-cut off as best illustrated at I116 in Fig. 9,
this having the same effect as providing the open
ing or slot 62 in the previously described con
struction. Thespring 56a which corresponds with
the spring 56 previously described is arranged
eccentrically with respect to the axis of the shaft
reduced diameter portion. Also, that the trans
verse wall of the cap member 39a is provided with
a central pocket in which a bushing II4, for the
inner end of the shaft 32a is received. The bush
ing H4, therefore, provides an outboard bearing
for the shaft 32a. It may also be noted that in
stead of the pin and boss construction employed
in the ?rst described construction for maintain
ing the plate member 540. against rotation, in the
construction illustrated in Figs. '7, 8, and 9 the
2,405,061
r
l1
plate member 54a, as best brought out in Fig. 9,
is provided with an integral radially projecting
12
housing movable axially with respect to said rotors
and relatively rotatable with respect thereto, said‘
projection or boss H6 on its periphery which is
wall having a flat face arranged in parallel and
loosely received within the groove or notch H8
formed in the inner wall of the cap member 30a, 11 opposed relation with respect to the end faces
of said rotors remote from said face of said hous~
this construction simply providing an alternative
method of maintaining the plate member 54a
against rotation with the shaft 32a.
In the construction illustrated in Figs. 10 and
11 the same main body portion 28a is employed ,
as in the construction illustrated in ‘Figs. '7, 8,
and 9. The cap member 301) is different, however,
the extended side wall portions of the construc
tion illustrated in Figs. 7, 8, and 9 being elim~
inated as well as the ?lter screen and sheet metal
cap employed in the previous construction.
In
this case the cap is provided with an inlet pas~
ing, spring means constantly urging said movable
wall toward said face of said housing, said face
of said housing being provided with a pair of
ports therein one registering with the suction
side of said rotors and the other registering with
the discharge side of said rotors forming the sole
means for admitting and discharging ?uid
through said housing to and from the space with
in said rotor, the outer of said rotors being pe
ripherally imperforate and bodily shiftable ax
ially in said housing whereby said outer rotor
may follow the movement of said movable wall in
the movement of the latter toward. and from said
face of said housing in response to variations in
respectively, which are the same as in the pre~ 20 pressure on the discharge side of said pump
sage I20, threaded to receive an inlet pipe I22,
which discharges directly into the space between
the righthand end of the rotors 20a and 2211.
viously described construction, and the end wall
of the cap member 301). The plate member 5413
and spring 56b are substantially the same as the
plate member 54a and the spring 56a in the pre
viously described construction. In this case the
structure, whereby to provide a by-pass passage
of varying cross-sectional area between said outer
rotor and said face of said housing between said
ports and said movable wall being formed to pro
vide constant open communication between the
suction side of said pump and that face of said
shaft 32b, corresponding with the shafts 32 and
well remote from said rotors.
32a of the previously described constructions, is
2. In a pump structure, in combination, a hous
provided with an enlarged inner end I24 upon
ing having a ?at face therein, a shaft rotatably
which the plate member 54b is rotatably received
and the extreme free end portion of which is ro 30 mounted in said housing in perpendicular rela
tionwith respect to said face, an inner rotor driv
tatably received in a bushing I26 carried by the
ingly connected to said shaft within said housing
transverse end wall of the cap member 30b. The
in substantial contact with said face, an outer
plate member 541) in this case is cut away on its
rotor within said housing surrounding said inner
suction side in the same manner as in the con
struction of the plate member shown in Figs. '7, 35 rotor in eccentric relation with respect thereto,
a wall within said housing movable axially with
81, and 9 but in this case instead of being held
respect to said rotors and relatively rotatable with
against rotation in the same manner as in such
respect thereto, said wall arranged in opposed re
previously described construction, the plate mem
lation with respect to those end faces of said
ber 54b is provided with a notch I30 in its'periph
cry and the cap member 30b is provided with an 40 rotors remote from said flat face of said housing,
spring means constantly urging said movable wall
integral inwardly projecting rib or boss I32 which
is received therein. Otherwise the construction
illustratedin Figs. 10 and 11 is the same as that
illustrated in Figs. '7, 8, and 9 and functions in
the same manner.
7
toward said ?at face of said housing, said ?at
face of said housing having a pair of ports therein
one of which is in communication with the inlet
side of the pumping space between said rotors
and the other of which is in communication with
the discharge side of the pumping space between
said rotors forming the sole means for admit
In Fig. 12 a modi?ed form of construction for
maintaining the plate or movable end wall mem
ber against rotation with respect to the enclosing
cap member is illustrated. The shaft in this case
is illustrated at 320, the cap member at 30c, ‘
the outer rotor at 220, the inner rotor at 200, the
movable end wall of plate member at 54c, and its
cooperating spring at 56c, and all of which parts
correspond with the equivalently numbered parts
of under the influence of the discharge pressure
acting on that end face thereof opposed to said
of the previously described constructions and '
which function in the same general manner. In
outer rotor to follow the movement of said mov
ting and discharging ?uid through said housing
to and from the space within said rotor, the outer
of said rotors being peripherally imperforate and
bodily movable Within said housing axially there
flat face of said housing whereby to enable said
this case, however, the plate member 540 is pro
able wall in response to variations in discharge
pressure occurring in said pump, thereby provid
ing a by-pass passage of varying cross-sectional‘
(30 size between said outer rotor and said ?at face
cap member 300 is provided with a hollow boss
of said housing and extending between said
I42 in which the projection I40 is loosely received
ports, and said movable wall being formed to pro
thus to maintain the plate member 540 against
vide constant open communication between the
rotation with the shaft 326.
suction side of said pump and that face of said
Having thus described my invention, what I
wall remote from said rotors.
claim by Letters Patent is:
3. In a rotary pump, in combination, a housing
1. In a rotary pump, in combination, a housing
having a flat face therein, a shaft rotatably
having a substantially ?at face therein, a shaft
mounted in said housing in perpendicular rela
rotatably mounted in said housing in perpendic
tionship with respect to said face, a peripherally
ular relation with respect to said face and project
imperforate inner rotor within said housing fixed
ing therebeyond, a pair of rotors within said hous
for equal rotation with said shaft in concentric
ing arranged with one end face of each thereof
relation
with respect thereto and said shaft pro
in opposed and parallel relation with respect to
jecting beyond one end of said rotor, a second
said face of said housing and one of said rotors
peripherally imperforate rotor in said housing in
being driven by said shaft, a wall within said,
vided with an integral axially parallel pin portion
I 40 cast integrally therewith and projecting to
the right therefrom as viewed in Fig. 12. The
enveloping and eccentric relation with respect
2,405,061
13
to said inner rotor, said rotors providing co
operating pumping elements, said face of said
housing having an inlet and an outlet port ar
14
mounted on said projecting end of said shaft
within said housing, means cooperating between
said wall and housing preventing relative rota
tion between said wall and housing, and single
spring means cooperating between said housing
and wall constantly urging said wall towards said
rotors, said spring means being arranged in ec
centric relation with respect to the axis of said
shaft and with the center of pressure thereof
ranged in operative relation with respect to the
suction and discharge sides of said rotors respec
tively and forming the sole means for the intro
duction and discharge of liquid to and from said
rotors, a wall relatively rotatably and axially mov
ably mounted on said projecting end of said shaft
within said housing, means cooperating between 10 approximately in balancing relation with respect
to the discharge pressure of said pump acting on
said wall and housing preventing relative rota
'he opposite side of said wall.
tion between said wall and housing, said wall be
5. In a rotary pump, in combination, a housing
ing formed to provide constant open communi
having
a ?at face therein, a shaft rotatably
cation between the suction side of said rotors and
that face of said wall remote from said rotors, 15 mounted in said housing in perpendicular rela
tionship with respect to said face, a peripherally
and spring means cooperating between said hous~
imperforate inner rotor within said housing ?xed
ing and wall constantly urging said wall towards
for equal rotation with said shaft in concentric
said rotors, said spring means being arranged in
relation with respect thereto and said shaft pro
eccentric relation with respect to the aXiS of said
jecting beyond one end of said rotor, a second
shaft and with the center of pressure thereof
peripherally imperforate rotor in said housing in
approximately in balancing relation with. respect
enveloping and eccentric relation with respect to
to the discharge pressure of said pump acting on
said inner rotor, said rotors providing cooperat
the opposite side of said wall.
ing pumping elements, said face of said housing
4. In a rotary pump, in combination, a housing
having a ?at face therein, a shaft rotatably
having an inlet and an outlet port arranged in
mounted in said housing in perpendicular rela
tionship with respect to said face, a peripherally
imperforate inner rotor Within said housing ?xed
for equal rotation with said shaft in concentric
relation with respect thereto and said shaft pro
forming the sole means for the introduction and
discharge of liquid to and from said rotors, a wall
jecting beyond one end of said rotor, a second '
peripherally imperforate rotor in said housing in
enveloping and eccentric relation with respect to
said inner rotor, said rotors providing coopera
ing pumping elements, said face of said housing
having an inlet and an outlet port arranged in
operative relation with respect to the suction
and discharge sides of said rotors respectively
and forming the sole means for the introduction
and discharge of liquid to and from said rotors, a
wall relatively rotatably and axially movably
operative relation with respect to the suction and
discharge sides of said rotors respectively and
relatively rotatably and axially movably mounted
on said projecting end of said shaft within said
housing, means cooperating between said wall
and housing preventing relative rotation between
said wall and housing, said wall being formed to
provide constant open communication between
the suction side of said rotors and that face of said
wall remote from said rotors, and spring means
cooperating between said housing and wall con
stantly urging said wall towards said rotors.
CLARENCE W. SHAW.
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