Information
-
Patent Grant
-
6305437
-
Patent Number
6,305,437
-
Date Filed
Wednesday, May 31, 200024 years ago
-
Date Issued
Tuesday, October 23, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Jacyna; J. Casimer
- Huynh; Khoa D.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 141 1
- 141 9
- 141 100
- 141 144
- 141 145
- 141 59
- 141 73
-
International Classifications
-
Abstract
A rotary union assembly for use in a rotary filler device comprising a first product supply conduit, a second product supply conduit, and a product supply turret rotatably coupled to the first product supply conduit and the second product supply conduit, to, in turn, maintain substantially sealed coupling therebetween.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a rotary union assembly, and more particularly, to a rotary union assembly, for use in association with a filler device, which efficiently coordinates a plurality of input supplies to a product supply turret associated therewith.
2. Background Art
Rotary union assemblies have been known in the art for years. Indeed, such assemblies are sometimes associated with rotary filling devices. While these rotary union assemblies have become commercially available, problems associated both with cleanliness and coordinating a plurality of input supplies remains largely problematic.
It is therefore an object of the present invention to provide a reliable and simple rotary union assembly which is capable of efficiently coordinating the supply of, among other things, product, electricity, a pneumatic source, a vacuum source, a cleaning material, and/or a cleaning solution to a product supply turret for use therewith, and to otherwise remedy the detriments and/or complications associated with conventional rotary union assemblies known in the art.
These and other objects of the present invention will become apparent in light of the present specification, claims, and drawings.
SUMMARY OF THE INVENTION
The present invention is directed to a rotary union assembly for use in a rotary filler device comprising: (a) a first product supply conduit; (b) a second product supply conduit; and (c) a product supply turret rotatably coupled to the first product supply conduit and the second product supply conduit, to, in turn, maintain substantially sealed coupling therebetween.
In a preferred embodiment of the invention, the product supply turret includes: (a) at least one first product disbursement conduit in fluid communication with the first product supply conduit, wherein the at least one first product disbursement conduit is capable of being placed in fluid communication with a first fill valve; and (b) at least one second product disbursement conduit in fluid communication with the second product supply conduit, wherein the at least one second product disbursement conduit is capable of being placed in fluid communication with a second fill valve.
The present invention is further directed to a method for supplying product through a rotary union assembly comprising the steps of: (a) providing a first product supply conduit; (b) providing a second product supply conduit; (c) providing a product supply turret having at least one first product disbursement conduit and at least one second product disbursement conduit; (d) associating the first product supply conduit with the at least one first product disbursement conduit; (e) associating the second product supply conduit with the at least one second product disbursement conduit; and (f) supplying a product through at least one of the first and second product supply conduits.
The present invention is also directed to a method of cleaning a rotary union assembly comprising the steps of: (a) providing a first product supply conduit; (b) providing a second product supply conduit; (c) providing a product supply turret having at least one first product disbursement conduit and at least one second product disbursement conduit; (d) associating the first product supply conduit to the at least one first product disbursement conduit; (e) associating the second product supply conduit with the at least one second product disbursement conduit; (f) associating at least one of the at least one first product disbursement conduits with at least one of the at least one second product disbursement conduits; and (g) providing a cleaning fluid through one of the first and second product supply conduits, wherein the cleaning fluid will proceed to the other of the first and second product supply conduits.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the drawings wherein:
FIG. 1
of the drawings is a cross-sectional view of a rotary union assembly in accordance with the present invention;
FIG. 2
of the drawings is a top plan view of a filler device associated with a rotary union assembly in accordance with the present invention; and
FIG. 3
of the drawings is a fragmented cross-sectional view of the filler device of FIG.
2
.
DETAILED DESCRIPTION OF THE INVENTION
While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and described herein in detail several specific embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.
It will be understood that like or analogous elements and/or components, referred to herein, are identified throughout the drawings by like reference characters.
Referring now to the drawings and to
FIG. 1
in particular, a cross-sectional schematic representation of a first embodiment of rotary union assembly
10
is shown, which generally comprises product supply means
12
, pneumatic supply means
14
, electrical supply means
16
and vacuum supply means
18
.
As is shown in
FIGS. 2 and 3
, rotary union assembly
10
is primarily intended for use in association with filler device
200
, which is capable of filling associated containers and/or bags with any one of a number of materials in solid, liquid, and/or gaseous states, including, for example, condiments (i.e catsup and mustard), wine, motor oil, battery acid—just to name a few.
It will be understood that the
FIGS. 1-3
are merely schematic representations. As such, some of the components have been distorted from their actual scale for pictorial clarity.
Product supply means
12
is shown in
FIG. 1
as including first product supply conduit
22
, second product supply conduit
24
, product supply turret
26
and rotatable connecting means
28
. As will be explained in greater detail below, product supply means
12
, essentially supplies product from storage tanks (not shown) to the individual containers.
First product supply conduit
22
, as shown in
FIG. 1
, includes first end
40
, second end
42
, outer wall
44
, inner wall
46
. As can be seen, outer wall
44
and inner wall
46
define product flow volume
50
, and inner wall
46
defines conduit volume
52
. Inner wall
46
fully separates product flow volume
50
and conduit volume
52
. As can be seen in
FIG. 1
, while a majority of the product flow volume
50
is in a vertical orientation, second end
42
of first product supply conduit
22
includes 90 degree elbow region
54
so that a portion of product flow volume
50
is in a substantially horizontal orientation. As will be understood, elbow region
54
is associated with a supply line which is in fluid communication with the product/fluid storage tank (not shown).
Each of outer wall
44
and inner wall
46
comprise a substantially circular cross-sectional shape configuration with substantially concentric longitudinal axis. In turn, the volume defined by these walls is substantially cylindrical in cross-section. Of course, other cross-sectional shapes are likewise contemplated and the invention is not limited to circular cross-sections. Additionally, it is contemplated that the longitudinal axis of each of the inner wall and the outer wall may be distally spaced from each other, however, certain advantages are realized if the longitudinal axis of each, correspond.
With respect to materials, preferably, first product supply conduit
22
comprises a stainless steel material having a sufficient thickness to support the pressure exerted by the product. Such a material is preferably resistive to corrosion and which is quite durable. Such a material is readily acceptable for use in the food industry and is approved for use by the FDA. For other applications, the material utilized may comprise any metal or alloy thereof, which may optionally include a coating. Additionally, a synthetic plastic material or a composite material may be utilized.
Second product supply conduit
24
is shown in
FIG. 1
as being substantially similar to first product supply conduit
24
and includes first end
60
, second end
62
, outer wall
64
, inner wall
66
and elbow region
72
. Outer wall
64
and inner wall
66
define product flow volume
68
and inner wall
66
defines conduit volume
70
. Elbow region
72
is shown at a 60 degree angle, however other angles of inclination of the elbow region are likewise contemplated. Inner wall
66
fully isolates volume
68
from volume
70
.
Product supply turret
26
is shown in
FIG. 1
as including first product chamber
81
, at least one first product disbursement conduit
82
, second product chamber
83
and at least one second product disbursement conduit
84
. In the contemplated embodiment, product supply turret
26
includes five first product disbursement conduits which are substantially similar to product disbursement conduit
82
, and five second product disbursement conduits which are substantially similar to product disbursement conduit
84
. Each of the first product disbursement conduits are in fluid communication with first product chamber
81
and, in turn, first product supply conduit
22
. Similarly, each of the second product disbursement conduits are in fluid communication with second product chamber
83
and, in turn, second product supply conduit
24
.
First product disbursement conduit
82
will be described with the understanding that each of the first product disbursement conduits are substantially identical. Specifically, as shown in
FIG. 1
, first product disbursement conduit
82
includes first end
86
, second end
88
, clamp
90
and fitting
92
. First end
86
is associated with first disbursement conduit
82
so as to be in fluid communication therewith. Clamp
90
and fitting
92
are positioned proximate second end
88
. The clamp and the fitting are utilized to retain first product disbursement conduit
82
in fluid communication with the filling conduit
210
and one of the filling valves
140
A-
148
A of rotary fill device
200
. In the embodiment shown, wherein product supply turret
26
includes five first product disbursement conduits, the shape of the first product disbursement chamber
81
is configured so as to substantially evenly distribute and guide product (fluid) to each of the five first product disbursement conduits.
Second product disbursement conduit
84
will be described with the understanding that each of the second product disbursement conduits are substantially identical. As shown in
FIG. 1
, second product disbursement conduit
84
includes first end
94
, second end
96
, clamp
98
and fitting
100
. First end
94
is associated with second product chamber
83
so as to be in fluid communication therewith. Clamp
98
and fitting
100
operate in the same fashion as clamp
90
and fitting
92
by connecting to filling conduit and to filling valves.
In the embodiment shown, the first and second product disbursement conduits are configured so that they feed alternating filling valves. Specifically, as shown in
FIG. 2
of the drawings, first product disbursement conduits are associated with each of the valves identified as
140
A-
148
A, whereas second product disbursement conduits are associated with each of the valves identified as
140
B-
148
B. As will be explained, among other advantages, the alternating association of valves facilitates the eventual cleaning of the system.
Rotatable connecting means
28
is shown in
FIG. 1
as comprising first rotatable coupling
102
and second rotatable coupling
104
. First rotatable coupling
102
includes seal member
106
and bearing
108
. Seal member
106
may comprise various mechanical seals, such as a mechanical ceramic based seal, as well as various rubber, carbon and plastic seals. The type of seal utilized is not critical as long as the seal is capable of providing a substantially fluid impervious seal which is capable of withstanding rotation of the turret and the supply conduit over millions of cycles. Bearing
108
comprises a conventional bearing which facilitates the controlled rotation of product supply turret
26
relative to first product supply conduit
22
. Of course, other systems which facilitate low friction rotation of the turret relative to the first supply conduit
22
are contemplated for use.
Second rotatable coupling
104
, as shown in
FIG. 1
, includes seal member
110
and bearing
112
. First rotatable coupling
102
is substantially identical to second rotatable coupling
104
in structure and operation. As will be understood, the second rotatable coupling
104
facilitates the rotation of product supply turret
26
relative to second product supply conduit
24
in a substantially fluid-tight configuration.
Electricity supply means
16
is shown in
FIG. 1
as comprising rotatable electric conduit
121
, rotatable coupling
123
, transfer case
125
, external conduit
127
, connecting member
129
and electrical wiring (not shown). The electricity supply means facilitates the providing of electricity to the product supply turret
26
continuously as the turret rotates relative to the first and second product supply conduits
22
and
24
, respectively.
Specifically, rotatable electric conduit
121
extends through conduit volume
52
and includes proximal end
132
and distal end
134
. Proximal end
132
is fixed to product supply turret
26
. External conduit
127
is in communication with rotatable electric conduit
121
and positioned at the proximal end thereof. Connecting member
129
is in communication with rotatable electrical conduit
121
and positioned at the distal end thereof. Transfer case
125
and rotatable coupling
123
are associated with rotatable electric conduit
121
and positioned at proximal end
134
thereof Rotatable coupling
123
permits stable rotation of electric conduit within volume
52
relative to first product supply conduit
22
about substantially the same axis of rotation as the product supply turret
26
.
As will be understood, electrical power is provided to the product supply turret
26
by wiring that extends through external conduit
127
, rotating electrical conduit
121
and finally connecting member
129
. Inasmuch as rotating electrical conduit
121
rotates relative to external conduit
127
, transfer case
125
is supplied to facilitate and maintain electrical connectivity between the electrical wiring of the external conduit and the wiring of the rotating electrical conduit
121
and connecting member
129
.
While rotating electrical conduit is shown as extending substantially the length of product supply conduit
22
, it is likewise contemplated that rotating electrical conduit
121
may extend only partially through the product supply conduit, wherein the transfer case, the rotatable coupling and the external conduit extend into product supply conduit
22
toward product supply turret. Of course other embodiments are likewise contemplated which can provide electrical connectivity between the non-rotating product supply conduits
22
,
24
and the rotating product supply turret
26
.
Pneumatic supply means
14
is shown in
FIG. 1
as comprising at least one pneumatic supply connection
141
, at least one pneumatic conduit
142
, at least one pneumatic connection
144
and means
145
for facilitating rotative coupling of the connection with the pneumatic conduit. Pneumatic supply connection
141
is configured so as to accept an air supply line such as an air hose (not shown). Pneumatic conduit
142
extends through at least a portion of conduit volume
52
between inner wall
46
and rotating electrical conduit
121
. Pneumatic conduit joins supply connection
141
to pneumatic connection
144
in a substantially fluid tight configuration. Thus, air supplied to pneumatic supply connection
141
can be directed to the pneumatic connections. Each pneumatic connection
144
includes an end configured to readily attach to an air line that extends to one of the components on product supply turret
24
, such as a filling valve.
Vacuum supply means
18
is shown in
FIG. 1
as comprising rotating vacuum conduit
150
, at least one connecting coupling
152
, external connecting coupling
154
and rotation facilitating means
156
. Rotating vacuum conduit
150
includes proximal end
158
and distal end
160
. Proximal end
158
is associated with product supply turret
26
. Each of the at least one connecting coupling
152
is in fluid communication with rotating vacuum conduit
150
. As will be understood, connecting coupling
152
is then attached to a container, a bag or the like to facilitate the removal of any air or other materials (i.e. fluids) that may be in the bag.
External connecting coupling
154
is in fluid communication with distal end
160
of rotating vacuum conduit
150
. Inasmuch as the rotating vacuum conduit
150
rotates relative to external connecting coupling
154
, seals, such as seal
162
are provided to minimize leaking of this connection. Rotation facilitating means
156
comprises bearing
163
that is positioned so as to permit low-friction rotation of rotating vacuum conduit
150
relative to second product supply conduit
24
.
Prior to operation, rotary union assembly
10
is assembled and positioned in a rotary filler device, such as rotary filler device
200
(FIGS.
2
and
3
). Once positioned, fill valves
140
A-
148
A are coupled to first product disbursement conduits
82
and fill valves
140
B-
148
B are coupled to second product disbursement conduits
84
. Specifically, as shown in
FIG. 2
, every other fill valve is associated with the same product supply conduit so that half of the fill valves are filled with product from first product supply conduit
22
and half of the fill valves are filled with product from the second product supply conduit
24
.
To couple a selected fill valve to first product disbursement conduit
82
, a conduit, such as conduit
210
(
FIG. 3
) is connected to the respective fill valve at one end and, as shown in
FIG. 1
, to second end
88
of first product disbursement conduit
82
by way of fitting
92
and clamp
90
. In a similar manner, to couple a selected fill valve to second product disbursement conduit
84
, a conduit, such as conduit
212
(
FIG. 3
) is connected to the desired fill valve at one end and, as is shown in
FIG. 1
, to second end
96
of second product disbursement conduit
84
by way of fitting
100
and clamp
98
.
Next, devices, which are pneumatically powered (i.e. by compressed air), are associated with pneumatic supply means
14
. Specifically, pneumatic supply connection
141
is associated with an outside pneumatic source, such as a compressor, which is capable of providing the desired pneumatic supply at a desired rate. In an embodiment wherein the fill valves are controlled pneumatically, pneumatic lines (not shown) are associated with the fill valve and connected to pneumatic connection
144
(FIG.
1
). Once these connections are established, the fill valve is in fluid communication with the pneumatic source via pneumatic supply connection
141
, pneumatic conduit
142
and pneumatic connection
144
. Of course, the specific number of connections, such as pneumatic connection
144
, can be varied depending on the particular requirements for any given embodiment.
Subsequently, any electrically driven components associated with product supply turret
26
can be wired to the wiring that extends through rotating electrical conduit
121
and connecting member
129
. As explained above, by way of transfer case
125
, electrical connectivity between the wiring in rotating electrical conduit
121
and external conduit
127
is maintained during rotation of the product supply turret
26
.
As shown in
FIG. 1
, should any component which rotates with product supply turret
26
require a vacuum connection, such a component is placed in fluid communication with connecting coupling
152
of vacuum supply means
18
. Connecting coupling
152
, as explained above, may comprise any one of a number of different coupling connections such as a snap connection, a threaded connection and the like.
Once all of the connections for each of the product supply means
12
, pneumatic supply means
14
, electricity supply means
16
and vacuum supply means
18
are established and their supply is activated, rotary union assembly
10
is ready for operation.
Specifically, in operation, as shown in
FIGS. 1 and 2
, product supply turret
26
begins to rotate relative to first product supply conduit
22
and second product supply conduit
24
. Yet, by way of rotatable connecting means
28
and
104
, seals are maintained at interfaces of product supply turret
26
and each of the product supply conduits
22
,
24
.
As shown in
FIG. 1
, rotating electrical conduit
121
is attached to product supply turret
26
at its proximal
132
, and rotates with product turret
26
. Rotatable coupling
123
maintains steady low friction rotation of the rotating electrical conduit relative to first product supply conduit
22
, and, transfer case
125
maintains electrical connectivity of the rotating wiring relative to the stationary wiring.
As shown in
FIG. 1
, pneumatic connections, such as pneumatic connection
144
is coupled to product supply turret
26
, and in turn, pneumatic conduit
142
and rotates therewith. Rotative coupling means
145
maintains fluid communication between pneumatic supply conduit
142
and pneumatic supply connections
141
and to insure an uninterrupted supply of pneumatic power during rotation and operation of product supply turret
26
.
Likewise, as shown in
FIG. 1
, proximal end
158
of rotating vacuum conduit
150
is attached to product supply turret
26
and rotates therewith. Distal end
160
is maintained in a steady, low-friction rotation relative to second product supply conduit
24
by way of rotation facilitating means
156
.
As product supply turret
26
rotates and operation of the fill valve apparatus proceeds, supply turret
26
supplies product to each of the fill valves from product supply means
12
. Specifically, product passes through first product supply conduit
22
from first end
40
to second end
42
. Subsequently, the product is directed beyond seal member
106
of first coupling
102
into first product chamber
81
which is rotating with product supply turret
26
. At such time, the product is distributed to each of the first product disbursement conduits
82
, to the respective fill valves and, in turn, to the respective container associated therewith.
As can be appreciated, at any one time, certain of the fill valves will be in the open position (i.e. container filling position) and certain of the fill valves will be in the closed position (i.e. container filled or no container attached). Thus, the rate of flow from first product chamber
81
to each of the first product disbursement conduits
82
will be varied and the flow rate is controlled by the fill valve.
Product is also directed to second product supply conduit
24
from first end
60
to second end
62
. At that time, the product is directed beyond the seal member of second coupling
104
into second product chamber
83
which is rotating. In turn, the product is directed from second product chamber
83
to the respective second product disbursement conduits
84
. As explained above, since certain fill valves will be open and others will be closed, the supply to each second product disbursement conduit at any given time varies and is generally controlled by the fill valve.
During the filling operations and the rotation of product supply turret
26
, electrical supply is provided as needed by electricity supply means
16
, pneumatic power as needed is supplied by pneumatic supply means
14
, vacuum supply as needed is supplied by vacuum supply means
18
. None of these means are disrupted by the rotation of the product supply turret
26
.
From time to time it becomes necessary to clean product supply means
12
. One manner in which to clean the product supply means comprises the feeding of a cleaning (or CIP) solution through the product supply means. In particular, any containers attached to fill valves are removed. Next, each fill valve associated with first product supply conduit
22
is coupled to a fill valve associated with second product supply conduit
24
. As explained above, wherein supply to the fill valves is alternated, proper coupling of the fill valves only requires the coupling of a fill valve to an immediately adjacent fill valve.
Once each fill valve is coupled to another fill valve, a cleaning solution is supplied to first product supply conduit
22
. The cleaning solution travels through first product supply conduit
22
from first end
40
to second end
42
and then enters first product chamber
81
wherein it is distributed to each of the first product disbursement conduits
82
. The first product disbursement conduits distribute the cleaning solution to every other fill valve (i.e.
140
A -
148
A). Inasmuch as each fill valve
140
A-
148
A is coupled to one of fill valves
140
B-
148
B, the cleaning solution is directed through each of the fill valves
140
B-
148
B back to second product disbursement conduit
84
. At such time the solution proceeds through second product chamber
83
and eventually through second product supply conduit
24
from second end
62
to first end
60
where it can be collected for filtering and reuse, or for disposal.
The cleaning solution can likewise be reversed so that the solution is introduced through second product supply conduit
24
and collected at first product supply conduit
22
for filtering and reuse or for disposal.
Once the cleaning of the product supply conduit is completed, fill valves
140
A-
148
A are disconnected from respective fill valves
140
B-
148
B and the system is again ready for operation. Advantageously, by alternating fill valves
140
A-
148
A with fill valves
140
B-
148
B, and by providing two product supply conduits, in the embodiment shown, only five short hoses (or conduits) are required to connect the respective fill valves to prepare the system for cleaning.
The foregoing description merely explains and illustrates the invention and the invention is not limited thereto except insofar as the appended claims are so limited, as those skilled in the art who have the disclosure before them will be able to make modifications without departing from the scope of the invention.
Claims
- 1. A rotary union assembly for use in a rotary filler device, comprising:a first product supply conduit having a first product inlet; a second product supply conduit having a second product inlet; and a product supply turret having a first product chamber and a second product supply turret having a first product chamber and a second product chamber, the product supply turret rotatably coupled to the first product supply conduit and the second product supply conduit, to, in turn, maintain substantially sealed coupling therebetween, wherein the product supply turret is positioned such that the first product supply conduit is positioned above the product supply turret and capable of feeding product from the first product inlet to the first product chamber in a downward direction, and the second product supply conduit is positioned below the product supply turret and capable of feeding product from the second product inlet to the second product chamber in an upward direction.
- 2. The rotary union assembly according to claim 1, wherein the product supply turret includes:at least one first product disbursement conduit in fluid communication with the first product supply conduit, wherein the at least one first product disbursement conduit is capable of being placed in fluid communication with a first fill valve; and at least one second product disbursement conduit in fluid communication with the second product supply conduit, wherein the at least one second product disbursement conduit is capable of being placed in fluid communication with a second fill valve.
- 3. The rotary union assembly according to claim 2, wherein:the at least one first product disbursement conduit comprises at least two first product disbursement conduits, each associated with a distinct first fill valve; the at least one second product disbursement conduit comprises at least two second product disbursement conduits, each associated with a distinct second fill valve; wherein the first and second fill valves are arranged so as to alternate between first fill valves and second fill valves about the rotary union assembly.
- 4. The rotary union assembly according to claim 3, wherein:the at least one first product disbursement conduit comprises five first product disbursement conduits, each associated with a distinct first fill valve; and wherein the at least one second product disbursement conduit comprises five second product disbursement conduits, each associated with a distinct second fill valve.
- 5. The rotary union assembly according to claim 1, further comprising means for supplying electricity to the product supply turret.
- 6. The rotary union assembly according to claim 5, wherein the electricity supply means comprises:a rotatable electrical conduit associated with the product supply turret, wherein the conduit includes at least one wire; an external conduit including at least one wire; and a transfer case, to, in turn, maintain electrical connectivity between the at least one wire of the rotatable electrical conduit and the at least one wire of the external conduit during rotation of the product supply turret, and rotatable electrical conduit, relative to the external conduit.
- 7. The rotary union assembly according to claim 6, wherein one of the first and second product supply conduits includes an inner wall extending there through, the inner wall defining a conduit volume, at least a portion of the rotatable electrical conduit extending through the conduit volume.
- 8. The rotary union assembly according to claim 1 further comprising a vacuum supply means.
- 9. The rotary union assembly according to claim 8, wherein the vacuum supply means comprises:a rotatable vacuum conduit associated with the product supply turret; a connecting coupling coupled to the rotating vacuum conduit; an external connecting coupling associated with the rotating vacuum conduit and capable of coupling to a vacuum source; and means for facilitating rotation of the rotating vacuum conduit relative to one of the product supply conduits while maintaining vacuum in the rotating vacuum conduit.
- 10. The rotary union assembly according to claim 9, wherein one of the first and second product supply conduits includes an inner wall extending there through, the inner wall defining a conduit volume, at least a portion of the rotating vacuum conduit extending through the conduit volume.
- 11. The rotary union assembly according to claim 1, further comprising pneumatic supply means.
- 12. The rotary union assembly according to claim 11, wherein the pneumatic supply means comprises:a pneumatic supply connection; a pneumatic conduit associated with the pneumatic supply connection; at least one pneumatic connection; and means for rotatably coupling the pneumatic connection to the pneumatic conduit in a substantially fluid tight coupling.
US Referenced Citations (14)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2215712-A |
Sep 1989 |
GB |