Fabricated rotor for rotary valves

A rotor for a rotary valve of the type including a housing providing a rotor chamber with a material inlet and a material outlet and a drive shaft journaled in said housing for supporting said rotor in said rotor chamber. The rotor includes a rotor shaft operatively connectable to the drive shaft and disposable in said rotor chamber. The rotor shaft has a plurality of longitudinally disposed, circumferentially spaced between recesses in which an edge of a plurality of vanes are received. The recesses include a slot preferably with a dovetail cross-sectional configuration, with the edge of the vanes having a comparable cross-sectional configuration. A pair of shrouds are included on either side of the vanes.

This invention relates to rotary valves and more particularly to a rotor 
for such valves which may be readily removed for cleaning and quickly 
reinstalled to minimize the down time of the valve. 
In the prior art, there has been developed a type of rotary valve which 
generally consists of a housing having a rotor chamber and a removable 
cover plate defining an end wall of the rotor chamber, a drive shaft 
journaled in the housing of the assembly and having an end portion 
projecting into the rotor chamber, and a rotor removably mounted on the 
drive shaft end portion whereby the rotor may be removed from the rotor 
chamber by removing the cover plate on the housing and sliding the rotor 
off of the drive shaft end portion and passing it through the opening in 
the housing provided by the removal of the cover plate. Such a valve 
assembly particularly is adapted for use where sanitary conditions are 
required such as the chemical, food processing and pharmaceutical 
industries. The assembly permits the rotor to be periodically removed, 
cleaned and replaced to maintain optimum sanitary operating conditions. 
Such type of valve assembly is more specifically illustrated and described 
in U.S. Pat. Nos. 4,059,205, 4,600,032 and 4,830,043 which are 
incorporated herein by reference. 
Typically, the rotors of such valves are fabricated by cutting a piece of 
tubular metal stock of a desired diameter to a proper length, machining 
the tubular member to provide internal splines or other means of securing 
the rotor to the drive shaft of the valve, forming and welding a plurality 
of metal vanes to the outer surface of the tubular member to form a 
plurality of circumferentially spaced vanes, and then forming and welding 
a pair of axially spaced, annular metal shrouds on the tubular member and 
the end edges of the vanes to provide a pair of end walls and a plurality 
of pockets which are adapted to receive product from an inlet of the valve 
housing, convey the product to the rotor chamber and discharge the product 
through an outlet of the valve housing. Commonly, such rotor components 
have been formed of mild steel, stainless steel or aluminum, and are 
welded together. 
Rotors of the type described, however, have been found not to be suitable 
for all applications. In the pharmaceutical and food processing industries 
in particular, where product contamination must be avoided, the rotor 
components usually are formed of stainless steel which substantially 
increases the cost of the valve. In addition, the fabrication process is 
comparatively expensive. It thus has been found to be desirable to provide 
such a rotor construction which not only is compatible with the product 
being processed through the valve but economical to manufacture. 
Accordingly, the principal object of the present invention is to provide an 
improved rotor for a rotary valve. 
Another object of the present invention is to provide an improved rotor for 
a rotary valve suitable for metering bulk materials such as grains, 
granules, pellets, chips, powders and the like. 
A further object of the present invention is to provide an improved rotor 
for a rotary valve particularly suitable for use in the chemical, food 
processing and pharmaceutical industries. 
A still further object of the present invention is to provide an improved 
rotor for a rotary valve which may be readily removed from the valve 
housing, cleaned and reinstalled within the housing with a minimum of 
downtime. 
Another object of the present invention is to provide an improved rotor for 
a rotary valve which will prevent contamination of the product being 
processed. 
A further object of the present invention is to provide an improved rotor 
for a rotary valve which is compatible and non-reactive with the product 
being processed through the valve. 
A still further object of the present invention is to provide an improved 
rotor for a rotary valve which is simple in construction, comparatively 
easy to manufacture and highly effective in service.

Referring to FIGS. 1 through 3, there is illustrated a rotor 10 embodying 
the present invention which generally includes a rotor shaft 11 adapted to 
be mounted on the end of a drive shaft of a rotary valve of a type as 
previously described, within a valve chamber therein having a product 
inlet opening and a product outlet opening, a plurality of vanes 12 and a 
pair of shrouds 13 and 14. As best shown in FIG. 1, rotor shaft 11 is 
formed from a piece of cylindrical bar stock and includes a cylindrical 
section 15 and a reduced cylindrical section 16. Cylindrical section 15 is 
provided with an annular flange 17 formed on an outer end thereof and a 
plurality of circumferentially spaced slots 18. A best shown in FIG. 3, 
each of the slots has a dovetail cross-sectional configuration. Reduced 
section 16 is provided with a threaded portion 19 for securing the rotor 
onto the drive shaft of a valve in which the rotor is installed, with 
rotor section disposed within the rotor chamber of the valve. 
Alternatively, the rotor as described may be formed of tubular stock with 
an internally splined surface to permit the rotor to be removably mounted 
on a splined end portion of a drive shaft of the valve. In either 
instance, the rotor shaft may be formed of a metal such as mild steel, 
stainless steel or aluminum, or a plastic material, depending on the 
application. 
Vanes 12 are substantially similar in configuration. Each of the vanes has 
a substantially rectangular configuration including a pair of end edges 20 
and 21, an outer edge 22 and an inner edge portion 23 having a 
cross-sectional configuration comparable to the cross-sectional 
configuration of each of slots 18 of the rotor shaft to permit each of the 
vanes to be slid into a slot 18 of the rotor shaft and thus be firmly 
secured thereto, projecting radially relative to the rotational axis of 
the rotor shaft. The axial lengths of the vanes are substantially similar 
to the axial lengths of slots 18 so that when the vanes are mounted on the 
rotor shaft, they will project radially, out of shaft section 15 as shown 
in FIG. 2. 
Shroud 13 has an annular configuration including an inner circular opening 
24 to permit the shroud to be mounted on the rotor shaft with shaft 
section 15 projecting through opening 24 and the shroud engaging inner 
annular surface 25 of annular end flange 17. Shroud 14 is configured 
similarly to shroud 13 having an outside diameter similar to the outside 
diameter of shroud 13 and an opening 26 having a diameter similar to the 
diameter of rotor section 16 so that when shroud 14 is mounted on the 
rotor shaft, shaft section 16 will be received through shroud opening 26 
and the shroud will engage annular surface 27 provided by reduced rotor 
section 16. 
In the manufacture of the rotor shown in FIGS. 2 through 3, with the 
components formed as described, shroud 13 is first slid onto the rotor so 
that rotor section 15 is received through shroud opening 24 and shroud 13 
engages annular flange surface 25 to form a first end wall of the rotor. 
With shroud 13 thus positioned, vanes 12 are installed by sliding the 
dovetailed inner edge portions 23 into slots 18 in rotor section 15 so 
that end edges 20 thereof engage positioned shroud 13. Shroud 14 is then 
mounted on the rotor shaft with reduced section 16 received through shroud 
opening 26 and the inner face thereof engaging end edges 21 of the vanes 
and annular surface 27, forming an opposite end wall of the rotor. With 
the vanes and shrouds thus positioned on the rotor shaft, the components 
are further secured together by means of a plurality of grooved pins 28 
inserted through a plurality of openings 29 in shroud 14 and registrable 
openings in end edges 21 of the vanes, and a plurality of pins 30 inserted 
through a plurality of openings 31 in shroud 13 and registrable openings 
in end edges 20 of the vanes. With the rotor components thus assembled and 
secured together, there will be provided a rotor having a plurality of 
circumferentially spaced pockets or sockets 32 formed by the rotor shaft, 
the radially disposed vanes and the shrouds forming the end walls of the 
pockets. 
Preferably, the vanes and shrouds utilized in the embodiment shown in FIGS. 
1 through 3 are formed of plastic, and pins 28 and 30 are formed of nylon 
which may be press-fit into aligned openings in the shrouds and vanes. 
FIG. 1 illustrates a rotor 40 also embodying the present invention which 
includes a rotor shaft 41, a plurality of vanes 41 and a pair of shrouds 
42 and 43. The rotor shaft is adapted to be operatively connected to a 
drive shaft of the valve and includes an intermediate cylindrical section 
44 and a pair of reduced, cylindrical end sections 45 and 46 providing a 
pair of outwardly facing, annular surfaces. Similar to rotor shaft section 
15, rotor shaft section 44 is provided with a plurality of 
circumferentially spaced slots 47, each having a dovetail cross-sectional 
configuration. Vanes 41 are comparable to vanes 12 shown in FIGS. 1 
through 3 and include inner edge portions having dovetail cross-sectional 
configurations to permit the vanes to be slid into and secured in slots 47 
of the rotor shaft. Shrouds 42 and 43 have similar annular configurations 
and are adapted to be inserted onto reduced rotor shaft sections 45 and 46 
and engage the annular end surfaces provided by the reduced shaft sections 
as shown in FIG. 4 to provide a plurality of circumferentially spaced 
pockets or sockets 48. As in the embodiment shown in FIGS. 1 through 3, 
the shrouds are adapted to be secured to the end edges of the vanes by 
means of a plurality of pins 49 press-fit into registered openings in the 
shrouds and end edges of the vanes. The shaft of such embodiment may be 
formed of either a metal or a plastic, the shrouds and vanes preferably 
are formed of a plastic material and the pins preferably are formed of 
nylon. 
The embodiment shown in FIG. 5 is similar to the embodiment shown in FIG. 4 
and further is provided with a pair of jamb nuts for firmly securing the 
shrouds against the end edges of the vanes. The Figure illustrates a rotor 
50 including a rotor shaft 51, a plurality of vanes 52 and a pair of 
shrouds 53 and 54. Rotor shaft 51 is similar to rotor shaft 41 including a 
cylindrical intermediate section 55 and a pair of reduced end portions 56 
and 57. Intermediate rotor section 55 is provided with a plurality of 
circumferentially spaced slots, each having a dovetail cross-sectional 
configuration which are adapted to receive a plurality of vanes similar to 
vanes 41 described in connection with the embodiment shown in FIG. 4. 
Shrouds 53 and 54 are mounted on rotor shaft reduced sections 56 and 57 
and engage the end edges of the vanes. The shrouds are secured to and 
urged against the end edges of the shrouds by means of a pair of jamb nuts 
58 and 59 threaded onto the reduced sections of the rotor shaft and run up 
against the outer faces of the shrouds, and a plurality of pins 60 
press-fit into registered openings in the shrouds and the end edges of the 
vanes as in the previously described embodiments. The shrouds cooperate 
with the vanes and intermediate section of the rotor shaft to provide a 
plurality of circumferentially spaced pockets or sockets 61. 
FIG. 6 illustrates a further modification of any of the embodiments shown 
in FIGS. 1 through 5. In this particular modification, the end edges 70 of 
each of the vanes are formed to flare outwardly or at a small angle 
relative to a radius of the rotor shaft on which the vanes are mounted so 
that when a shroud 71 is urged into engagement with an annular shoulder or 
surface of the rotor shaft, the shroud will be caused to flex and thus 
urge the inner face of the shroud into engagement with the end edges of 
the vanes in sealing relation. The center portions of the shrouds may be 
urged together by any of the methods described in connection with the 
aforementioned embodiments, and the shrouds further may or may not be 
further secured to the shrouds by means of a set of pins. 
In lieu of slots having a dovetail cross-sectional configuration, the slots 
may be provided with any other configuration providing an undercut to 
prevent the vanes from displacing outwardly. As an example, the slots may 
have an inverted T-shape or L-shape cross-sectional configuration. 
As previously mentioned, the rotor shaft in any of the aforementioned 
embodiments and modifications may be formed of a metal or any suitable 
thermoplastic material which has the characteristics of a metal, is 
readily machinable and preferably is resistant to chemical attack. 
Preferably, the rotor is formed of an acetal copolymer material 
manufactured and sold by the Westlake Plastics Company of Lenni, Pa., 
under the trademark WESTLAKE. Such material has the characteristics of a 
metal, i.e., stiffness, dimensional stability, structural strength and 
resiliency, is lightweight and has low thermal conductivity. It is 
self-lubricating and wear resistant, and further resists a wide range of 
chemicals including salt, bases, aliphatic and aromatic hydrocarbons, 
halogenated hydrocarbons, alcohols, esters, ethers, ketones and most other 
organic and inorganic chemicals which makes it particularly suitable for 
pharmaceutical and food processing applications. The rotor also may be 
formed of material manufactured by the E.I. duPont de Nemours and Company 
of Wilmington, Delaware, and sold under the trademark DELRIN. The vanes 
and shrouds also may be formed of the same plastic materials. Preferably, 
the pins and jamb nuts are formed of nylon. 
From the foregoing detailed description, it will be evident that there are 
a number of changes, adaptations and modifications of the present 
invention which come within the province of those persons having ordinary 
skill in the art to which the aforementioned invention pertains. However, 
it is intended that all such variations not departing from the spirit of 
the invention be considered as within the scope thereof as limited solely 
by the appended claims.