Refrigerated agitator assembly

A refrigerated agitator assembly is provided including a rotatable agitator shaft, first and second split hub assemblies, and a plurality of agitator tubes. The rotatable agitator shaft defines a fluid supply passage, a fluid supply port, and a fluid return port. The first split hub assembly is secured proximate a first end of the agitator shaft so as to be rotatable with the agitator shaft. The first split hub assembly defines a supply hub duct coupled to the fluid supply port and a return hub duct coupled to the fluid return port. The second split hub assembly is secured proximate a second end of the agitator shaft so as to be rotatable with the agitator shaft and defines a transfer hub duct. A first agitator tube is secured to the first and second split hub assemblies and extends from the supply hub duct of the first split hub assembly to the transfer hub duct of the second split hub assembly. A second agitator tube is secured to the first and second split hub assemblies and extends from the transfer hub duct of the second split hub assembly to the return hub duct of the first split hub assembly.

BACKGROUND OF THE INVENTION 
The present invention relates to a refrigerated agitator assembly and, more 
particularly, to a refrigerated agitator assembly for a dough mixer. 
Friction and viscous shear encountered during mixing cause a temperature 
rise in a substance being mixed. This temperature rise becomes more severe 
as mixing speed increases and can adversely affect a mixing process. 
Accordingly, mixers, particularly dough mixers, are most effective when 
equipped with some type of temperature control means, whereby the 
temperature of the substance to be mixed may be stabilized at a 
preselected level or maintained below a predetermined threshold. For 
example, bread dough should be mixed at a temperature of about 78.degree. 
F. to 80.degree. F. 
U.S. Pat. No. 4,275,568, issued to Zielsdorf on Jun. 30, 1981, teaches a 
temperature controlled dough mixer including a mixing bowl provided with a 
cooled sheet panel, a pair of cooled end panels, and a cooled breaker tube 
extending between the end panels. A cooled agitator may be rotatably 
mounted between the end panels of the mixing bowl. Unfortunately, the 
specific design taught in the Zielsdorf patent is relatively difficult and 
expensive to manufacture and maintain and is not compatible with many 
existing mixing schemes. The Zielsdorf patent is representative of the 
continuing need in the art of substance mixing for a mixer and 
refrigerated agitator assembly that may be manufactured and maintained in 
a cost effective manner, is compatible with existing mixing schemes, and 
that provides sufficient cooling during mixing operations. 
BRIEF SUMMARY OF THE INVENTION 
This need is met by the present invention wherein a refrigerated mixer and 
agitator assembly are provided including a rotatable agitator shaft 
defining a fluid supply passage, a fluid supply port, and a fluid return 
port. A pair of split hub assemblies are secured to opposite ends of the 
agitator shaft and define hub ducts therein for passing cooling fluid. 
In accordance with one embodiment of the present invention, a refrigerated 
agitator assembly is provided comprising a rotatable agitator shaft, first 
and second hub assemblies, and a plurality of agitator tubes. The 
rotatable agitator shaft defines a fluid supply passage, a fluid supply 
port, and a fluid return port. The first hub assembly is secured proximate 
a first end of the agitator shaft so as to be rotatable with the agitator 
shaft. The first hub assembly defines a supply hub duct coupled to the 
fluid supply port and a return hub duct coupled to the fluid return port. 
The second hub assembly is secured proximate a second end of the agitator 
shaft so as to be rotatable with the agitator shaft and defines a transfer 
hub duct. A first agitator tube is secured to the first and second hub 
assemblies and extends from the supply hub duct of the first hub assembly 
to the transfer hub duct of the second hub assembly. A second agitator 
tube is secured to the first and second hub assemblies and extends from 
the transfer hub duct of the second hub assembly to the return hub duct of 
the first hub assembly. 
The first hub assembly preferably comprises a first split hub assembly 
including a first set of complementary hub portions secured to one another 
about the agitator shaft. Similarly, the second hub assembly preferably 
comprises a second split hub assembly including a set of complementary hub 
portions secured to one another about the agitator shaft. The first set of 
complementary hub portions and the second set of complementary hub 
portions may be secured together with respective sets of hub securing 
hardware. The first agitator tube may be mechanically coupled to a first 
one of the first set of complementary hub portions and to a first one of 
the second set of complementary hub portions to form a first split hub 
unit. Similarly, the second agitator tube may be mechanically coupled to a 
second one of the first set of complementary hub portions and a second one 
of the second set of complementary hub portions to form a second split hub 
unit. Preferably, the first split hub unit is securable to and detachable 
from the second split hub unit by engaging and disengaging respective sets 
of hub securing hardware. 
The fluid supply port and the fluid return port may be at the same end of 
the agitator shaft. The fluid supply passage is preferably divided into 
fluid inlet passage and a fluid outlet passage. The fluid inlet passage 
may extend between a fluid supply and the fluid supply port. The fluid 
outlet passage may extend between the fluid return port and the fluid 
supply. The fluid supply passage may be divided by a supply passage 
conduit oriented about a central axis of the rotatable agitator shaft. The 
fluid supply passage may be coupled to the fluid supply via a rotary union 
and the rotary union may be arranged to define respective portions of the 
fluid inlet passage and the fluid outlet passage. The rotary union may 
comprise a stationary rotary union body defining a rotary union fluid 
inlet and a rotary union fluid outlet, a rotatable rotary union shaft, a 
rotary union pipe, and a rotary union end cap. 
The agitator shaft preferably comprises a shaft body having first and 
second ends defining a longitudinal shaft axis and a substantially 
cylindrical shaft periphery and the fluid supply passage is formed in the 
agitator shaft along a portion of the longitudinal shaft axis. The fluid 
supply port and the fluid return port may be formed in the shaft periphery 
so as to be in fluid communication with the fluid supply passage. The 
agitator shaft may further define a fluid transmission duct formed in the 
agitator shaft at an opposite end of the shaft from the fluid supply 
passage, the fluid supply port, and the fluid return port. The fluid 
transmission duct preferably comprises a transverse bore formed in the 
agitator shaft. 
The refrigerated agitator assembly preferably further comprises a third 
agitator tube secured to the first and second hub assemblies and extending 
from the supply hub duct of the first hub assembly to the transfer hub 
duct of the second hub assembly. Alternatively, the third agitator tube 
may extend from the transfer hub duct of the second hub assembly to the 
return hub duct of the first hub assembly. The agitator tubes preferably 
extend substantially parallel to the agitator shaft. The refrigerated 
agitator assembly further preferably comprises respective roller bars 
spaced from and oriented substantially parallel to each agitator tube. 
In accordance with another embodiment of the present invention, a 
refrigerated agitator assembly is provided comprising a rotatable agitator 
shaft, first and second split hub assemblies, and a plurality of agitator 
tubes. The rotatable agitator shaft comprises first and second ends and 
defines a fluid supply passage, a fluid supply port, and a fluid return 
port. The first split hub assembly is secured proximate the first end of 
the agitator shaft so as to be rotatable with the agitator shaft and 
defines a supply hub duct coupled to the fluid supply port. Further, the 
first split hub assembly comprises a first set of complementary hub 
portions secured to one another about the agitator shaft. The second split 
hub assembly is secured proximate the second end of the agitator shaft so 
as to be rotatable with the agitator shaft and defines a transfer hub 
duct. The second split hub assembly comprises a second set of 
complementary hub portions secured to one another about the agitator 
shaft. A first agitator tube is secured to the first and second hub 
assemblies and extends between the supply hub duct of the first hub 
assembly and the transfer hub duct of the second hub assembly. A second 
agitator tube is secured to the first and second hub assemblies and 
extends between the supply hub duct of the first hub assembly and the 
transfer hub duct of the second hub assembly. 
Preferably, the first split hub additionally defines a return hub duct 
coupled to the fluid return port. The transfer hub duct may extends 
between the first agitator tube and the second agitator tube. The fluid 
supply port and the fluid return port may be at the same end of the 
agitator shaft. 
The respective sets of complementary hub portions are preferably secured 
together with respective sets of hub securing hardware. The first agitator 
tube may be mechanically coupled to a first one of the first set of 
complementary hub portions and a first one of the second set of 
complementary hub portions to form a first split hub unit. The second 
agitator tube may be mechanically coupled to a second one of the first set 
of complementary hub portions and a second one of the second set of 
complementary hub portions to form a second split hub unit. In this 
manner, the first split hub unit is securable to and detachable from the 
second split hub unit by engaging and disengaging the hub securing 
hardware. 
In accordance with yet another embodiment of the present invention, an 
agitator shaft is provided comprising a shaft body, a fluid supply 
passage, a fluid supply port, and a fluid return port. The shaft body has 
first and second ends defining a longitudinal shaft axis and a 
substantially cylindrical shaft periphery. The fluid supply passage is 
formed in the agitator shaft along a portion of the longitudinal shaft 
axis. The fluid supply port is formed in the shaft periphery so as to be 
in fluid communication with the fluid supply passage. Similarly, the fluid 
return port is formed in the shaft periphery so as to be in fluid 
communication with the fluid supply passage. 
The agitator shaft may further define a fluid transmission duct formed in 
the agitator shaft at an opposite end of the shaft from the fluid supply 
passage, the fluid supply port, and the fluid return port. The fluid 
transmission duct may comprise a transverse bore formed in the agitator 
shaft. 
In accordance with yet another embodiment of the present invention, a 
refrigerated mixer is provided comprising a mixing bowl and a refrigerated 
agitator assembly according to the present invention positioned to rotate 
within the mixing bowl 
Accordingly, it is an object of the present invention to provide a 
refrigerated agitator assembly and a refrigerated mixer incorporating the 
same, wherein the arrangement of the refrigerated agitator assembly 
provides for substantial temperature stabilization within the mixer. It is 
a further object of the present invention to provide such an agitator 
assembly in a manner to ensure that the assembly may be manufactured and 
maintained at a reasonable expense. Other objects of the present invention 
will be apparent in light of the description of the invention embodied 
herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A refrigerated agitator assembly 10 according to the present invention is 
illustrated in FIGS. 1 and 2. The remaining figures include illustrations 
of specific components of an agitator assembly 10 according to the present 
invention. The refrigerated agitator assembly 10 comprises a rotatable 
agitator shaft 12, a first split hub assembly 40, a second split hub 
assembly 50, first, second, and third agitator tubes 60, 62, 64 extending 
substantially parallel to the agitator shaft 12, and respective roller 
bars 70, 72, 74 associated with each agitator tube 60, 62, 64. The 
agitator assembly 10 is arranged relative to a mixing bowl 80, see FIG. 2, 
such that the agitator tubes 60, 62, 64 are positioned within the mixing 
bowl 80. 
Referring to FIGS. 2, 3, and 7, the rotatable agitator shaft 12 defines a 
fluid supply passage 21, a fluid supply port 24, and a fluid return port 
26. The fluid supply passage 21 is divided into a fluid inlet passage 22 
and a fluid outlet passage 23 by a supply passage conduit 28, see FIG. 3, 
oriented about a central longitudinal shaft axis 15 of the rotatable 
agitator shaft 12. The fluid inlet passage 22 extends between the fluid 
supply port 24 and a fluid supply 25 via a conduit aperture 19 formed in 
the supply passage conduit 28. The fluid supply is illustrated 
schematically in FIG. 3 and preferably comprises a reservoir of glycol or 
another suitable coolant. The fluid outlet passage 23 extends between the 
fluid return port 26 and the fluid supply 25. 
Referring now to FIGS. 2, 3 and 7, the rotatable agitator shaft 12 of the 
present invention comprises a shaft body 14 having first and second ends 
16, 18 defining a longitudinal shaft axis 15 and a substantially 
cylindrical shaft periphery 20. The fluid supply passage 21 is formed in 
the agitator shaft 12 proximate the first end 16 of the agitator shaft 12. 
The fluid supply passage 21 extends along the longitudinal shaft axis 15 
far enough to place the fluid supply port 24 formed in the shaft periphery 
20 in fluid communication with the fluid supply passage 21. The fluid 
return port 26 is also in fluid communication with the fluid supply 
passage 21. 
The agitator shaft 12 further defines a fluid transmission duct 27 formed 
in the agitator shaft 12 at an opposite end of the shaft from the fluid 
supply passage 21, the fluid supply port 24, and the fluid return port 26. 
The fluid transmission duct 27 comprises a transverse bore formed in the 
agitator shaft 12 and is positioned so as to be in fluid communication 
with the transfer hub duct 52 (see FIGS. 2, 4, and 5). 
As is illustrated in FIG. 3, the fluid supply passage 21 is coupled to the 
fluid supply 25 via a rotary union 30. The rotary union 30 defines a 
portion of the fluid inlet passage 22 and the fluid outlet passage 23. The 
rotary union 30 comprises a stationary rotary union body 31 defining a 
rotary union fluid inlet 32 and a rotary union fluid outlet 33. The rotary 
union fluid inlet 32 and the rotary union fluid outlet 33 are each coupled 
to the fluid supply 25. 
The rotary union 30 further comprises a rotatable rotary union shaft 34, a 
rotary union pipe 35, and a rotary union end cap 36. The rotary union pipe 
35 engages the supply passage conduit 28 and a rotary union bushing 38 is 
provided to seal the engagement. In this manner, the fluid inlet passage 
22 is defined within the interior of the supply passage conduit 28 and the 
rotary union pipe 35. Further, the fluid outlet passage 23 is defined 
about the exterior of the supply passage conduit 28 and the rotary union 
pipe 35. The supply passage conduit 28 is pressure fit within the tapered 
end of the fluid supply passage 21. 
The rotary union end cap 36, illustrated in detail in FIGS. 3 and 9, 
incorporates a number of fluid passing apertures 37 (see FIG. 9) to allow 
fluid traveling through the fluid outlet passage 23 to pass substantially 
unimpeded through the rotary union end cap 36, as indicated by directional 
arrows 39. The flow of fluid through the interior of the rotary union pipe 
35 is indicated by directional arrow 29. Merely a portion of the rotary 
union pipe 35 is illustrated in FIG. 9; however, a detailed illustration 
of the entire rotary union pipe 35 is presented in FIGS. 3 and 8. 
Referring now to FIGS. 1, 2, and 4-6, the first split hub assembly 40 is 
secured proximate a first end 16 of the agitator shaft 12 so as to be 
rotatable with the agitator shaft 12. The first split hub assembly 40 
defines a supply hub duct 42 coupled to the fluid supply port 24 and a 
return hub duct 44 coupled to the fluid return port 26. Similarly, the 
second split hub assembly 50 is secured proximate a second end 18 of the 
agitator shaft 12 so as to be rotatable with the agitator shaft 12. The 
second split hub assembly 50 defines a transfer hub duct 52. 
The first agitator tube 60 is secured to the first and second hub 
assemblies 40, 50 and extends from the supply hub duct 42 of the first 
split hub assembly 40 to the transfer hub duct 52 of the second split hub 
assembly 50. The second agitator tube 62 is also secured to the first and 
second hub assemblies 40, 50 and extends from the transfer hub duct 52 of 
the second split hub assembly 50 to the return hub duct 44 of the first 
split hub assembly 40. The third agitator tube 64 is also secured to the 
first and second hub assemblies 40, 50 and extends from the supply hub 
duct 42 of the first split hub assembly 40 to the transfer hub duct 52 of 
the second split hub assembly 50. It is contemplated by the present 
invention that the third agitator tube 64 may extend either from the 
supply hub duct 42 of the first split hub assembly 40 to the transfer hub 
duct 52 of the second split hub assembly 50 or from the transfer hub duct 
52 of the second split hub assembly 50 to the return hub duct 44 of the 
first split hub assembly 40. 
The above-described arrangement of the agitator assembly 10 enables cooling 
fluid to flow along a path beginning at the fluid supply 25, passing 
through the first end 16 of the agitator shaft 12 to the first split hub 
assembly 40, through the first and third agitator tubes 60 and 64 to the 
second split hub assembly 50 and the fluid transmission duct 27, through 
the second agitator tube 62, and returning to the fluid supply 25 via the 
first end of the agitator shaft 12. Thus, the fluid flow path begins and 
ends at the same end of the agitator shaft 12. Alternatively, it is 
contemplated by the present invention that the agitator assembly of the 
present invention may be arranged such that the fluid flow path may begin 
at one end of the agitator shaft 12 and terminate at an opposite end of 
the agitator shaft 12. As would be appreciated by those practicing the 
present invention, suitable sealing members should be provided at various 
locations within the agitator assembly 10, particularly where two distinct 
mechanical components including two distinct fluid passages or ducts 
engage and are in fluid communication with each other. 
The first split hub assembly 40 is referred to herein as a "split" assembly 
because it includes a first set of complementary hub portions 46, 48 
secured to one another about the agitator shaft 12. Similarly, the second 
split hub assembly 50 is referred to herein as a "split" assembly because 
it includes an additional set of complementary hub portions 56, 58 secured 
to one another about the agitator shaft 12. The first set of complementary 
hub portions 46, 48 are secured together with hub securing hardware 47 and 
the second set of complementary hub portions 56, 58 are secured together 
with hub securing hardware 57. The first and third agitator tubes 60, 64 
are mechanically coupled to a first one 46 of the first set of 
complementary hub portions and a first one 56 of the second set of 
complementary hub portions to form a first split hub unit 90. Similarly, 
the second agitator tube 62 is mechanically coupled to a second one 48 of 
the first set of complementary hub portions and a second one 58 of the 
second set of complementary hub portions to form a second split hub unit 
92. The first split hub unit 90 is securable to and detachable from the 
second split hub unit 92 by engaging and disengaging the hub securing 
hardware 47, 57. In this manner, the agitator assembly 10 of the present 
invention may be conveniently assembled, disassembled, and maintained. 
Having described the invention in detail and by reference to preferred 
embodiments thereof, it will be apparent that modifications and variations 
are possible without departing from the scope of the invention defined in 
the appended claims.