Rotary feeder system

The present invention provides a rotary feeder system having a rotor housing with an intake opening and means for discharging material spaced apart side walls. A rotor is positioned with its radially extending blades disposed within the rotor housing and its two ends of its shaft each extending through an aperture in one of the side walls. The shaft bearing and interconnection to the rotating means are each disposed outwards of the rotor housing and the apertures are sealed about the rotor shaft by a sealing assembly comprising a washer, a seal having a first and second ring wherein the second ring extends inward beyond the inner circumference of the first, said ring merging into a flange pressing upon said washer, and a retaining plate which bears against the second ring, tightening it against the washer. The washer and second ring of the seal are preferably formed of tetrafluoro-ethylene resin, and all joints between components within the rotor housing are welded to fill any crevices. The present invention also provides a rotary feeder wherein the gear shaft of the drive is received in a bore within the rotor shaft and these two shafts are precisely aligned by an alignment pin that is lodged through a bore in these shafts when the bores of the separate shafts are properly aligned, which permits the feeder to be disassembled for cleaning and then reassembled without resetting tolerances.

TECHNICAL FIELD OF THE INVENTION 
The present invention is in the technical field of rotary valves, 
particularly those considered sanitary rotary valves designed for 
minimizing or eliminating contamination of materials that pass through the 
valve. These rotary valves are also referred to in the art as feeders and 
sanitary feeders. 
BACKGROUND OF THE INVENTION 
Rotary valves or feeders generally comprise some form of rotor assembly 
having a plurality of vanes projecting radially from a shaft which vanes 
control the movement of material as it passes through the feeder. The 
rotor is enclosed in a housing having an intake mouth operationally open 
to a supply of the material being handled, which material flows into those 
pockets formed by adjacent vanes that are disposed facing the intake. Upon 
rotor rotation, the filled pockets turn to a position at which they are 
open to a means for discharging the material, such as a bottom discharge 
opening, and the material is released from the pocket. 
In some feeders, the movement of the material both in and out of the 
pockets is a gravitational effect, the intake mouth being disposed above 
the rotor assembly and the discharge means being an opening in the bottom 
of the rotor housing. The material could instead be discharged by blowing 
it in a horizontal direction into a discharge tube when the filled pocket 
turns to a position adjacent such discharge tube. In any instance, the 
feeder is generally disposed in a line, most often a vertical line with 
the material flow, and regulates the volume of material passing through 
the line per unit time. 
Materials whose flow can be controlled by such a feeder include solid 
materials of such suitable form, such as powders, small pellets, and the 
like, that material movement approaches a resemblence to fluid flow. 
When the material is intended for ingestion, particularly human ingestion, 
such as pharmaceuticals and foodstuff, it is desirable, and at times 
mandatory, that the surfaces of the feeder that come in contact with the 
material be free of crevices, cracks, pits, and the like, in which the 
material or other substances could become entrapped, and therein 
deteriorate, leading to contamination of material passing through the 
feeder. In certain applications, such as handling of dairy products, the 
U.S. Department of Agriculture requires rotary feeders to be free of such 
crevices, cracks, pits and the like, for approval. 
It is an object of the present invention to provide a rotary feeder that is 
not only easy to disassemble for cleaning its internal parts, but also is 
free from cracks, crevices, pits, and the like within the rotor housing 
and thus on all material contact surfaces. It is an object of the present 
invention to provide such a feeder while maintaining the integrity of the 
feed passage as to the avoidance of entrance of external contaminants. 
These and other objects will be made apparent by the disclosure of the 
invention and the description of the preferred embodiments of the 
invention. 
DISCLOSURE OF THE INVENTION 
The present invention is a rotary feeder having a rotor normally disposed 
within a rotor housing having an intake opening and means for discharging 
material, wherein the bearing surfaces for such rotor are disposed 
outwards of the housing, and further wherein the rotor shaft, which at 
both ends extends through apertures in the housing walls, is protected at 
its exit point by an annular seal assembly, the contact surfaces of which 
are formed of tetrafluoroethylene resin. 
Further, the rotor shaft at one end concentrically receives the end of a 
gear shaft and is precisely aligned therewith along the shaft's axial line 
by means of an alignment pin, at a position along its length outwards of 
the rotor housing, permitting the rotor to easily be precisely positioned 
within the rotor housing. The feeder assembly thus can easily be 
reassembled after cleaning. 
In preferred embodiment all joints within the rotor housing are welded 
whereby all crevices, cracks, pits, and the like, normally created by the 
joinder of two components, are filled and sealed.

PREFERRED EMBODIMENTS OF THE INVENTION 
In FIG. 1 is shown a rotary feeder system, designated generally by the 
reference number 10, comprising a motor 12, gear box 14, and rotary feeder 
16. The feeder 16, as shown, comprises a rotor housing 18 having a top 
intake opening 20 and a bottom discharge exit opening 22. The intake 
opening 20 preferably has a pair of opposed inclined sides 24 forming a 
two-sided chute which tends to guide the material passing through towards 
the axial center line of a rotor 26 shown mounted within the housing 18 
below the intake opening 20. The exit opening 22 can also be formed with a 
similar pair of sides (not shown) inwardly inclined towards each other. 
The rotor housing 18 is closed at its end opposite the gear box 14, i.e., 
its forward end 27, with an end plate 28 secured with wing nuts 30 for 
ease in removal. 
Referring now to FIG. 2 also, there is better seen the rotor 26 comprising 
a rotor stem or shaft 32, and extending radially therefrom a plurality of 
rotor vanes or blades 34. As shown, the rotor 26 includes six blades 34 
each spaced equidistant from adjacent blades 34. This rotor 26 is formed 
as a unitary component, all parts thereof being welded together, as 
opposed to bolting the separate parts to each other which would result in 
cracks and crevices at the joints and about the bolts in a component 
within the rotor housing 18 during use. 
The forward end 36 of the rotor shaft 32 is formed as a length of shaft of 
decreased diameter or a coaxial shaft stem 38, and a shoulder 39 between 
the stem 38 and the rotor shaft proper 32. 
From the rear end 40 of the rotor shaft 32 inward is formed with a bore 42 
(shown in phantom in FIG. 2) which receives the end of a gear shaft 44 
upon which is mounted an elongated strip or key 46. The key 46 is secured 
to the gear shaft 44 with a pair of set screws 48. 
The gear shaft 44 is provided with an alignment bore 50 that extends from 
one side to the other of the gear shaft 44 and is formed to receive an 
alignment pin 54. The rotor shaft 32 is provided with a pair of alignment 
bores 56 on opposite sides of the shaft bore 42 positioned so as to match 
the gear shaft alignment bore 50 when the rotor shaft 32 is so seated on 
the gear shaft 44 with respect to its axial line that the rotor blades 34 
are properly positioned within the rotor housing 18 spaced apart from the 
housing forward and rear walls. 
Near the tip of the alignment pin 54 are a set of spring-loaded ball pins 
52 that retract as the alignment pin 54 is being inserted through, or 
retracted from, the alignment bores 50,56 of the gear shaft 44 and rotor 
shaft 32, and spring back to protruding position when such shafts 44,32 
are spanned, to prevent accidental dislodgement of the alignment pin 54. 
The alignment pin 54 is disposed outwards of the rotor housing 18 and thus 
does not contribute any crevices or the like to the surfaces in contact 
with the material going through the feed passage. Further, this pin 54 can 
be lodged or dislodged by hand when the rotor housing 18 is closed. 
The gear shaft key 46 is fitted snugly within a groove 58 along the side of 
the shaft bore 46 and bears against the side of the groove 58 transmitting 
the torque from the gear shaft 44 to the rotor shaft 32. 
The above described interconnection between the rotor shaft 32 and gear 
shaft 44 is positioned outwards of the rotor housing 18, the rotor shaft 
32 projecting through an aperture 60 in the rear housing wall 62 which is 
sealed around the rotor shaft 32 by a sealing assembly comprising a washer 
64, preferably formed of tetrafluoro-ethylene resin, a 
tetrafluoro-ethylene resin tipped seal 66, and retaining plate 68, which 
sealing assembly is discussed in detail below. A similar assembly seals 
the forward end 36 of the rotor shaft 32 and the aperture through which it 
extends out of the rotor housing 18. 
Referring now to FIG. 3 also, the rotary feeder 16 is interconnected to the 
gear box 14 by braces 70 which holds these units together in a 
predetermined spaced-apart relationship. The means for fastening the 
braces 70 to the feeder 16 do not protrude through its rear housing wall 
62. 
The aperture 60 in the rear housing wall 62 through which the rear end 40 
of the rotor shaft 32 passes is formed to provide only minimal clearance 
for the rotor shaft 32 and the rear housing wall 62 is formed with an 
annular hollow 72 in its outer surface encircling the aperture 60, 
providing a seat for the sealing assembly. The sealing assembly, as 
mentioned briefly above, comprises first an annular gasket or washer 64 
formed of tetrafluoro-ethylene resin which closely encircles the rotor 
shaft 32 and fits within the hollow 72 bearing against its bottom wall. 
Adjacent the washer 64 is the annular seal 66 comprising a metal ring 74 
formed at its outer circumference with a forwardly extending flange 76 and 
at its inner circumference with an inner ring or tip 78 formed of 
tetrafluoro-ethylene resin. The seal 66 is positioned against the washer 
64 with its flange 76 extending from its opposite face, towards the rotor 
housing 18. The inner ring or tip 78 is concave towards the rotor housing 
18, encompassed by the ring formed by the outer flange 76. The seal 66 
also is seated within the hollow 72. 
Beyond the seal 66 is the retaining plate 68 having a center bore 80 
encircled by an annular boss 82 which presses directly on the metal ring 
74, pressing the flange 76 against the washer 64. This retaining plate 68 
is secured to the rear housing wall 62 with wing nuts 83 or other suitable 
means for fastening that do not protrude through the rear housing wall 62. 
The blades 34 of the rotor 26 span almost the entire distance between the 
inner surfaces of the rear housing wall 62 and the forward wall of the 
rotor housing 18, formed mainly by the front end plate 28, the clearance 
therebetween preferably being of the order of a few thousandths of an 
inch. Thus proper placement of the rotor 26 along its axial line thus is 
of great importance. 
The front end plate 28 is formed with a center aperture 84 through which 
the forward end 36 of the rotor shaft 32 projects beyond the shaft stem 
portion 38 and the shoulder 39. The forward end plate 28 on its outer 
surface is formed with an annular hollow 72a encircling the center 
aperture 84 and receiving a washer 64a, tipped seal 66a, and an annular 
boss 82a of a retaining plate 68a forming a sealing assembly as described 
above for the shaft aperture 60 of the rear housing wall 62. This 
retaining plate 68a is similarly secured to the front end plate 28 by a 
pair of wing nuts 83a or other means that do not protrude through to the 
inner surface of the forward end plate 28. 
The end plate 28 further includes a bearing cartridge 90 and cap 90a held 
in spaced apart relationship from the retaining plate 68a by a plurality 
of arms or braces 88. Such cap 90 is held opens towards, and in axial 
alignment with, the end plate aperture 84, and thus also with the center 
bore 80a of the retaining plate 68a when mounted on the end plate 28. 
Within such cartridge 90 is fitted a ball bearing 92 for the stem portion 
38 of the forward end 36 of the rotor shaft 32. The shoulder 39 of the 
rotor shaft 32 will be positioned outside of, and adjacent to, the bearing 
92. 
To disassemble the rotary feeder 16 for the purpose of cleaning the 
interior of the rotor housing 18, one merely unfastens the wing nuts 30 
securing the end plate 28 to the rotor housing 18, and removes the end 
plate 28 together with its sealing assembly, leaving the rotor shaft 32 
free at its forward end 36. Then the alignment pin 54, lodged through the 
rotor shaft 32 and gear shaft 44 at a position between the housing rear 
wall 62 and gear box 14, is removed, freeing the rotor 26 which then is 
pulled forward, out of the rotor housing 18 and off the gear shaft 44. The 
sealing assemblies, i.e., the retaining plates 68, 68a, the seals 66, 66a, 
and washers 64, 64a, can be removed from the rear housing wall 62 and end 
plate 28 for cleaning. 
Reassembly of the feeder 16 merely requires the reverse of the disassembly 
steps, the rotor 26 being repositioned without resetting tolerances by 
virtue of the precise alignment determined by the placement of the 
alignment pin 54. 
Referring now in particular to FIG. 3a, there is shown the rotor shaft 32 
at the point of exit through the rear housing wall 62 through the aperture 
60 therein. About the aperture 60 is formed the hollow 72 in which is 
seated first the washer 64 followed by the seal 66 which can be considered 
as comprising a first ring 74, preferably formed of metal, and a flange 76 
extending from the outer circumference of the first ring 74, that bears 
against the washer 64, a second inner ring or tip 78 that extends inwardly 
beyond the inner circumference of the first ring 74. The second ring 78, 
is preferably formed of tetrafluoro-ethylene resin is somewhat resilient 
and seals the rotor shaft 32. 
INDUSTRIAL APPLICABILITY OF THE INVENTION 
The present invention and its various embodiments and features are 
applicable to the material handling industries including without 
limitation the food processing, chemical, and pharmaceutical industries.