[0001] This invention relates to rotary displacement pumps for fluid substances, particularly
but not exclusively for human consumption.
[0002] It is an object of the present invention to provide such a pump which can be readily
dismantled to facilitate cleaning of the moving parts.
[0003] It is a further object of the invention to provide a pump which is capable of delivering
a predeterminmed quantity of a fluid substance.
[0004] It is a further object of the invention to provide a pump for use with fluid substances
having a viscosity which is such that the fluid will not flow within, or pass from
the pump unless the pump is activated.
[0005] Therefore,in accordance with the present invention,there is provided a rotary displacement
pump including a housing having an inlet and an outlet a first circular recess and
a second circular recess within the first recess, and disposed eccentrically thereof
with its periphery at one point coincident with the periphery of the first recess,
the said housing also including a rotatable annular member concentric with the second
recess and defining with the first recess a fluid flow passage communicating with
its inlet, and having an orifice.
[0006] The annular member is provided with a port or orifice to permit communication between
the fluid flow passage out the interior of the annular member and which is disposed
such that the interior communicates with the outlet. Blade means are provided for
rotation by said annular member within and concentric with its first recess.
[0007] A further feature of the invention lies in the provision of a detachable cover which
defines the outlet from the housing. According to a further feature of the present
invention,the inlet includes means for regulating fluid flow into the housing.
[0008] A still further feature of the invention comprises a spigot or like projection extending
from the detachable cover which support the blade or blades so as to be rotatable
by the annular member.
[0009] A rotary displacement pump in accordance with the invention will now be described,
by way of example only, with reference to the accompanying drawings, in which,
Figure 1 is a sectional view showing the interior of a pump in accordance with the
invention,
Figure 2 is a sectional view on line 'AA' of Figure 1,
Figure 3 is a side view of a cover for the pump,
Figure 4 is a sectional view showing an alternative form of pump in accordance with
the invention, and
Figure 5 is a sectional view on line 'BB' of Figure 2.
[0010] Referring to Figures 1, 2 and 3 of the drawings, 10 indicates a pump having a housing
11 adapted to detachably support a cover 12. The means for detachably supporting the
cover 12 on the housing 11 can be any known means, one such means will be described
hereafter.
[0011] The housing 11 is circular in cross-section as shown in Figure 1 of the drawings,
and a circular recess lla is provided in the housing and is concentric therewith.
A second circular recess llb is provided in the housing at the inner end of the recess
lla, the center of the recess llb being offset from the center of the recess lla by
a distance equal to half the difference between the diameters of the circular recesses
lla and llb.
[0012] Thus,as can be seen from Figure 2 of the drawings,the periphery of the recess llb
is coincident with the periphery of the recess lla at the lowest point 13 of the vertical
center line of the recesses lla and llb.
[0013] A disc 14, having a thickness no greater than, and preferably equal to the depth
of the recess llb, is rotatably mounted in the recess llb, and is drivingly connected
to a shaft 15 which extends through the housing 11.
[0014] The shaft 15 is connected by means not shown, to drive means, also not shown, which
are well known to those skilled in the art.
[0015] An inner housing or crown 16 is mounted on the disc 14 by means of pins 14a and comprises
an annular member having depth at least equal to the depth of the recess lla, and
preferably a depth such that it extends between the disc 14 and the inner portion
of cover 12.
[0016] It will be seen therefore that a passage 17 is defined between the inner bottom and
side walls of the recess lla, the inner portion of cover 12 and the outer periphery
of the inner housing or crown 16, which passage 17 progressively increases in width
as it extends in a clockwise direction from the point 13 to a point diametrically
opposite said point 13. Thereafter it progressively decreases in width as it extends
to point 13.
[0017] To permit communication between the passage 17 and the interior 18 of the inner housing
or crown 16, a circumferentially extending opening 19 is provided in the inner housing
or crown 16.
[0018] The housing 11 can be connected to a source of fluid substance, such as an ice cream
mix, by means of an adapter 20 which communicates with a bore 21 in the housing 11,
the bore 21 being connected to the passage 17 by means of an opening 22.
[0019] If required, the adapter 20 may be provided with holes 23 which register with an
air inlet hole 24 in the housing 11 to permit air to enter the bore of the adapter
20 and mix with the ice cream mix or other fluid substance flowing through the bore
21 into the passage 17.
[0020] A non-return valve comprising a ball 25 supported in the outlet end of the adapter
20, means 26 being provided to prevent the ball entering the passage 17 through the
opening 22. The means 26 comprises a screw extending through the wall of the housing
11, and into the bore 21. An additional hole 27 is provided for connection to a pressure
switch if needed.
[0021] A vane or blade 28, having a depth equal to the depth of recess lla, extends from
within the interior 18 of the inner housing or crown 16, through the opening 19 and
engages with the periphery of the recess lla and with the inside surface of cover
12 when the latter is mounted on housing 11.
[0022] The vane or blade 28 is mounted for pivotal movement about the center of the recess
lla, by means forming part of the cover l2.
[0023] As can be seen from Figure 3 of the drawings, the cover 12 which is circular is provided
with a centrally disposed spigot 29 which when the cover 12 is mounted on the housing
engages in a hole in the vane or blade 28. An outlet orifice 30 is provided in the
cover 12, and is positioned such that it communicates with the interior 18 of the
inner housing or crown 16. Appropriate means may be connected to outlet orifice 30,
for example refrigerating apparatus for producing ice cream from a mixture of an ice
cream mix and air.
[0024] The means for detachably securing the cover 12 on the housing may comprise any known
means, for example two studs 31 disposed at diametrically opposed positions on the
housing 11, and so mounted that when the cover is placed on the housing 11 with the
spigot 29 engaged in the hole in the blade or vane 28, winged nuts are fixed to studs
31 so that they engage with and retain the cover 12 in place.
[0025] Known sealing means such as gaskets, "O" rings, etc. may be used as required to prevent
the ice cream mix or other fluid substance from exiting the pump from elsewhere than
through outlet orifice 30.
[0026] When the above described rotary displacement pump 10 is to be used, and assuming
that it is primed with an ice cream mix or other fluid substance such that the substance
completely fills the bore 21, the passage 17 and the interior 18 of the inner housing
or crown 16, the shaft rotating means are actuated.
[0027] The disc 14 is thus rotated in a clockwise rotation whereupon the vane or blade 28
is moved by the inner housing 16 in the same direction thus moving the fluid substance
in front of it through the passage 17. The movement of the Vane or blade 28 compresses
the fluid in the progressively reducing volume portion of the passage 17 until the
pressure exceeds the pressure of the fluid in the inner housing. At this point,the
fluid being compressed by the blade or vane 28 enters the interior of the inner housing
or crown 16 and expels the fluid already in the interior out of the housing through
the orifice 30, until the vane or blade 28 is stopped by controlling the drive means
using known means.
[0028] During the above described movement of the vane or blade, as the vane passes over
the opening 22, ice cream mix or other fluid substance enters the bore 21, - flows
through the opening 22 and fills the space behind the vane or blade 28, until the
vane or blade reaches the position shown in broken lines in figure 1.
[0029] When it is necessar
y/clean the pump, the cover is removed by removal of the winged nuts from studs 31
and the blade or vane and housing interior are readily accessible.
[0030] It will be appreciated that the volume of the passage 17 and the inner housing or
crown 16 can be selected in accordance with the quantity of fluid substance to be
delivered upon each rotation of the pump.
[0031] Referring to Figures 4 and 5 of the drawings,110 indicate a pump having a housing
112 which is generally circular in cross section as shown in figure 4 of the drawings.
A circular recess 114 is formed in the housing 112 and is concentric therewith, whilst
a second circular recess 116 is formed in the housing 110 at the inner end of the
recess 114.
[0032] The centre of the recess 116 is disposed eccentrically of the centre of the recess
114 by a distance equal to half the difference between the diameter of circular recesses
114 and 116 in order that at point 119, the periphery of recess 114 is coincident
with the periphery of the recess 116.
[0033] A disk 118 having a thickness no greater than and preferably equal to the depth of
the recess 116 is rotatably mounted in the recess 116 and is drivingly connected to
a shaft 120 which extends through the housing 112.
[0034] The shaft 120 is connected to drive means, not shown.
[0035] The outer end of the recess 114 is sealed by a detachable cover 124.
[0036] An annular rotor 122 is mounted on the disk 118 and has a depth at least equal to
the depth of recess l14 and preferably a depth such that it extends between the disk
118 and the inner portion of a detachable cover 124, which seals the outer end of
the recess 114.
[0037] It will be seen therefore that a fluid flow path 126 is defined between the outer
periphery of the rotor 122, the periphery of the recess 114, the bottom of the recess
114, and the inner face of the detachable cover 124 which fluid flow path communicates
with an inlet 128 located upstream of the point 119 relative to the flow of fluid
through the path 126 and an outlet 130, located downstream of point 119 relative to
the flow of fluid through the path 126.
[0038] It will be seen from figure 4 of the drawings that the fluid flow path 26 progressively
increases in area as it extends towards an outlet zone 131, which communicates with
the outlet 130.
[0039] The detachable cover 124 is provided with a centrally disposed spigot 132 which supports
three blades or wipers 134 so that they project radially from the spigot 132. Each
blade extends through an axially extending slot 122a formed in the rotor 122 so that
they are circumfirentially equally spaced. Each blade is engaged by a sealing member
136 mounted in the rotor 122 to limit and preferably prevent the entry of fluid into
the centre of the rotor 122.
[0040] The blade has a width which is equal to the width of the first recess 114, and as
can be seen from figure 4 of the drawings the spigot 132 is disposed eccentrically
of the center of the rotor 122,whereby each blade when rotated through the flow path
126 will be in contact with the periphery of the recess 114 over a distance of at
least one hundred and twenty degrees or long enough to allow the following blade to
reach point 121, downstream of the inlet 128.
[0041] Each blade is freely rotatable relative to the spigot 132, thus when the rotor is
rotated in an anti-clockwise direction as viewed in figure 4 of the drawings,the blades
will be similarily rotated about the spigot 132.
[0042] A filter, not shown,is disposed in the inlet 128 to ensure that particles which are
larger than the minimum radial gap between the rotor 122 and the periphery of the
recess 114 do not enter the flow path.
[0043] When the above described rotary displacement pump 110 is to be used, and assuming
that it is primed with a fluid substance such that the substance completely fills
the fluid flow path 126, the drive shaft 120 is actuated. The disk 118 is thus rotated
in an anti-clockwise direction whereby the rotor 122 and thus the blades 134 are rotated
in the same direction thus moving the fluid substance through the fluid flow path
126. The movement of the blade(s) 134 which is or are in contact with the periphery
of the recess 114 moves the fluid which is downstream of this blade toward the outlet
130.
[0044] The rotation of a blade 134 from point 121 downstream also causes a pressure drop
across the vane area, and thus fluid is drawn in through the inlet 128 to replace
that fluid which has been pushed by the blade.
[0045] The above described pump may be rotated continuously so as to continuously discharges
fluid through the outlet 130, but it can also be used to discharge predetermined quantities
of the fluid. This is achieved by affecting one third of a revolution of the rotor,
whereby the pump will discharge a quantity of fluid which is equal to that contained
between a blade 134 whose tip is in contact with the periphery of the recess 114 at
point 121 and the next downstream blade 134.
[0046] It will be appreciated that since the rotor 122 is radially spaced from the periphery
of the recess 114 throughout its circumfirential extent except for point 119 and because
of the filter in the inlet 128, that aggregate which does enter the fluid flow path
will pass through radial gap between the rotor 122 and periphery of the recess 114
and will be pushed into outlet 130.
[0047] It will also be appreciated that because the tips of the blades 134 do not contact
the periphery of the recess 114 over the whole of its circumfirential extent, blade
wear will be reduced, and consequently pump life extended.
[0048] It is to be understood that whilst in the above described embodiments the rotors
16 and 122 are positively rotated and effect rotation of the blades 18 and 124 respectively,
the pump construction may be such that blades 28 and 134 are mounted on a driven shaft,
whilst the associated rotor is freely rotatable in the recess 112 or 114 respectively.
[0049] Thus upon rotation of the driven shaft supporting the blades, the rotor would be
rotated by the blades.
[0050] It will be appreciated that the pump may be manufactured from either metal or a plastic,
provided that where it is used with substances for human consumption the metal or
plastic is acceptable for such use.
[0051] Furthermore whilst the pump has been described in relation to a fluid whose viscosity
is such that it will not flow unless the pump is actuated, the outlet orifice of the
pump may be provided with means to permit the use of the pump with fluids which will
flow freely without the pump being actuated. Such means are well known to those skilled
in the art.
[0052] Although a particular embodiment of the invention has been described, it is not limited
thereto. For example, cover may be integral with the housing and the latter may be
made in two parts joined together.
1) A rotary displacement pump comprising:
a) a housing having an inlet, an outlet, a first circular recess and a second circular
recess which is within the first recess and which is disposed eccentrically thereof
with its periphery at one point near the outlet coincident with the periphery of the
first recess;
b) a rotor mounted in the second recess which extends across the first recess to define
with the housing a flow passage;
c) at least one blade or vane supported so as to project through the rotor and be
rotatable through the flow passage and concentrically of the first recess.
2) A rotary displacement pump as claimed in claim 1, in which the rotor comprises
an annular member through which the at least one blade projects.
3) A rotary displacement pump as claimed in claim 2, in which the rotor is provided
with sealing means for engagement with that part of the blade or vane extending therethrough.
4) A rotary displacement pump as claimed in claim 1 or claim 2 in which one end of
the first recess is defined by a cover detachably secured to the housing.
5) A rotary displacement pump as claimed in claim 1 in which a filter element is provided
in the inlet to the flow path.
6) A rotary displacement pump as claimed in claim 1, in which three blades or vanes
are provided.
7) A rotary displacement pump as claimed in claim 1, in which the inlet is disposed
such that it is adjacent to the point of the second recess which is closest to the
periphery of the recess.
8) A rotary displacement pump as claimed in claim 1, 2 or 3 in which the blade is
supported so as be freely rotatable on a spigot formed on said housing.
9) A rotary displacement pump as claimed in claim 1, 2 or 3, in which the rotor is
supported on a disc rotatably mounted in the second recess, and connected to a drive
shaft extending through the housing.
10) A rotary displacement pump as claimed in claim 4, in which the oulet is formed
in the cover defining one end of the first recess, and communicates with the flow
passage through an orifice in the rotor.
11) A rotary displacement pump as claimed in claim 1, in which the flow path is defined
such that the blade tip is coincident with the periphery of the first recess from
a point near the inlet for a distance which is less than the peripheral extent of
the first recess.
12) A rotary displacement pump as claimed in claim 4, in which said means detachably
securing said cover to said housing comprise catches, means mounting said catches
on said housing for rotation between a position to retain said cover on said housing,
and a further position to permit removal of said cover.
13) A rotary displacement pump as claimed in claim 1, including means for regulating
fluid flow into said inlet.
14) A rotary displacement pump as claimed in claim 13, in which said means comprise
a non-return valve means being provided to control movement of the valve.
15) A rotary displacement pump as claimed in claim 14, in which said non-return valve
comprises a ball and means defining a seat for said ball, means also being provided
for preventing said ball entering said inlet.
16) A rotary displacement pump as claimed in claim 9, in which said disc is equal
in thickness to the depth of said second circular recess.