U.S. patent number 3,799,622 [Application Number 05/213,076] was granted by the patent office on 1974-03-26 for multi-station loader for particulate material.
This patent grant is currently assigned to Universal Dynamics Corporation. Invention is credited to Homer C. Hek.
United States Patent |
3,799,622 |
Hek |
March 26, 1974 |
MULTI-STATION LOADER FOR PARTICULATE MATERIAL
Abstract
A multi-station loader useful in the loading of particular
solids entrained in a gaseous fluid is disclosed. During loading, a
vacuum is drawn on a chamber which is connected to a source of
material thus drawing the material into the chamber. During the
blow back operation the direction of the air circuit which during
the loading operation was drawing a vacuum on the chamber, is
reversed thus cleaning the filter and chamber and allowing material
to be discharged from its bottom into a material hopper. Loading is
only allowed to occur when a level switch attached to the chamber
indicates a need for material. The entire operation is controlled
by a cylindrical array of switches and by a cam driven at two
different speeds, dependent upon whether the loader is searching
for a chamber calling for material or actually loading a chamber.
Alternatively, the cam may be driven at the higher of the two
speeds and stopped by magnetic braking.
Inventors: |
Hek; Homer C. (Alexandria,
VA) |
Assignee: |
Universal Dynamics Corporation
(Woodbridge, VA)
|
Family
ID: |
22793655 |
Appl.
No.: |
05/213,076 |
Filed: |
December 28, 1971 |
Current U.S.
Class: |
406/23; 406/109;
406/28; 406/156; 406/172 |
Current CPC
Class: |
B65G
53/24 (20130101) |
Current International
Class: |
B65G
53/24 (20060101); B65G 53/04 (20060101); B65g
053/04 () |
Field of
Search: |
;302/62,28,21,59
;222/334 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
945,469 |
|
May 1949 |
|
FR |
|
947,239 |
|
Jan 1964 |
|
GB |
|
Primary Examiner: Blunk; Evon C.
Assistant Examiner: Lane; H. S.
Attorney, Agent or Firm: Stokes; William D.
Claims
What is claimed is:
1. A multi-station loader for loading material from a material
source comprising:
a. a plurality of loading stations;
b. means for coupling said plurality of loading stations to said
material source;
c. means for providing pneumatic drive, said means having intake
and exhaust ports;
d. valve means having a first port coupled to the intake of said
pneumatic drive providing means, a second port coupled to the
exhaust of said pneumatic drive providing means, a third port
coupled to said plurality of loading stations, and a fourth port,
said valve means further including rotor means rotatable to a first
position coupling the first port to the third port and the second
port to the fourth port for directing said pneumatic drive and
loading said loading stations and rotatable to a second position
coupling the first port to the fourth port and the second port to
the third port for reversing the flow of said pneumatic drive
within said loading station and cleaning the station;
e. a loading valve for each of said plurality of loading stations,
each of said valves having an input coupled to said means for
providing pneumatic drive and an output coupled to its respective
station;
f. switch means for detecting a need for material at each of said
plurality of stations;
g. variable speed electrical timing means; and
h. control means responsive to the detection of a need for material
by said switch means for actuating said loading valves, for varying
the speed of said electrical timing means and for controlling said
valve means.
2. A multi-station loader according to claim 1, wherein:
said electrical timing means includes a cam, and said control means
comprises an array of switches sequentially actuated by said
cam.
3. A multi-station loader according to claim 1, wherein:
said valve is positionable by a solenoid actuated by said control
means.
4. A multi-station loader according to claim 1 wherein said control
means includes an electrical circuit.
5. A multi-station loader according to claim 1 wherein said
variable speed electrical timing means has a first speed for
searching for a station requiring material and a second lower speed
for loading said station.
6. A multi-station loader for loading material from a material
source comprising:
a plurality of loading stations having means for receiving material
from said material source;
means for providing pneumatic drive;
loading means associated with each of said plurality of loading
stations for coupling said loading stations with said pneumatic
drive providing means;
valve means coupled to both said pneumatic drive providing means
and said loading means for directing said provided pneumatic drive
to said coupled loading stations and drawing material thereto from
said material source through said means for receiving material;
filter means at said coupled loading stations for preventing said
drawn material from entering said pneumatic drive providing
means;
detection means associated with each of said plurality of loading
stations for detecting a need for material at each of said
plurality of loading stations;
multiple speed timing means operational at a first scanning speed
for searching for one of said plurality of loading stations having
a detected material need;
control means responsive to the said detection means for actuating
said loading means associated with said detected one loading
station, said control means also for reducing the speed of said
multiple speed timing means to a second slower speed for a
predetermined time period required for loading the detected loading
station, said control means also for actuating said valve means at
the end of said predetermined load period for reversing said
provided pneumatic drive for blowing back said loaded loading
station and cleaning said filter means.
7. A multi-station loader according to claim 6, wherein:
said timing means includes a cam coupled thereto, and
said control means comprises an array of switches sequentially
actuated by said cam
8. A multi-station loader according to claim 6, wherein:
said loading means is positionable by a solenoid actuated by said
control means.
9. A multi-station loader for loading material from a material
source comprising:
a. a plurality of loading stations;
b. means for coupling said plurality of loading stations to said
material source;
c. means for providing pneumatic drive, said means having intake
and exhaust ports;
d. valve means having a first port coupled to the intake of said
pneumatic drive providing means, a second port coupled to the
exhaust of said pneumatic drive providing means, a third port
coupled to said plurality of loading stations, and a fourth port,
said valve means further including rotor means rotatable to a first
position coupling the first port to the third port and the second
port to the fourth port for directing said pneumatic drive and
loading said loading stations and rotatable to a second position
coupling the first port to the fourth port and the second port to
the third port for reversing the flow of said pneumatic drive
within said loading station and cleaning the station;
e. a loading valve for each of said plurality of loading stations,
each of said valves having an input coupled to said source of
material and an output coupled to its respective station;
f. switch means for detecting a need for material at each of said
plurality of stations;
g. an electrical timer;
h. a magnetic brake operatively connected to said electrical timer;
and
i. control circuit means scanned by said timer for actuating said
loading valves and applying the brake in response to a detection of
a need for material by said switch means.
10. A multi-station loader for loading material from a material
source comprising:
a. a plurality of loading stations;
b. means for coupling said plurality of loading stations to said
material source;
c. means for providing pneumatic drive and drawing said material
from said source to one of said plurality of loading stations;
d. filter means at said one loading station for preventing said
material from entering said means for providing pneumatic
drive;
e. a loading valve for each of said plurality of loading stations,
each of said loading valves having an input coupled to said source
of material and an output coupled to its respective station;
f. switch means for detecting a need for material at each of said
plurality of stations;
g. an electrical timer;
h. a magnetic brake operatively connected to said electrical timer;
and
i. control circuit means scanned by said timer for actuating said
loading valves and applying the brake in response to a detection of
a need for material by said switch means.
Description
The present invention relates to an improved method and apparatus
for the vacuum loading of Particulate material and more
specifically to a new and improved method and apparatus wherein the
Particulate material is sequentially fed to a plurality of stations
where it is collected and unloaded into a hopper which feeds this
material to a device which consumes the material at an uneven
rate.
In conventional systems, material is moved pneumatically through a
material line into a chamber. Pneumatic drive is provided by a
vacuum pump which is connected to the chamber through a vacuum
line. In order to prevent the material from entering the vacuum
line, a filter is provided at the point where the vacuum line
connects with the chamber.
When the vacuum is drawn, material is drawn into the material line,
and travels to the chamber, where it enters near the top and falls
by gravity to the bottom of the chamber. After a predetermined time
period, the vacuum pump stops, causing the weight of the material
to open the bottom of the chamber, thus allowing the collected
material to drop out into a hopper from which the material is
consumed at an uneven rate. Operation of this material dump
function is thus actuated by the loss of vacuum in the chamber.
Finally, it is necessary after each cycle to reverse the air flow
and clear the filter by electrically reversing the pump and blowing
back through the vacuum line.
This type of loader is commonly used to fill the hopper of a
material user such as a drier. A level switch is used to start the
loading operation when the level in the hopper reaches a
predetermined low level.
A more sophisticated version of the loader employs a single vacuum
pump and associated control to load, in sequence, several stations,
each equipped with identical vacuum chambers and filters.
In such an arrangement, the loader selects a station and loads it
for an adjustable period of time. The loading time is controlled by
a timer and after the loading operation has been completed dumping
occurs. It then automatically proceeds to the next station, and if
the switch indicates a low level, loads it. After this station is
loaded, it then proceeds to the next station, thus loading the
various stations until the cycle is completed.
Upon completion of the entire cycle of stations, the vacuum pump is
stopped. The pump is then run briefly in reverse, thereby blowing
back all the filters at once. All these functions are controlled by
a single timer motor driving a cam shaft with a cam for each
function on each station.
Although it is possible to arrange for each station to be blown
back immediately after filling, this would entail the use of an
additional cam for each station, and would result in a great deal
of lost time. Another disadvantage of separate blow-back of each
station in this type of system is the additional wear and tear on
the pump motor due to starting and stopping of the pump.
Multiple station systems of the type described above suffer from
several distinct disadvantages. Effectiveness of the blow-back
operation is hampered by the fact that the pump has to clean the
filters by blowing back all of them at the same time. On the other
hand, if each station is blown back separately, the additional
starting and stopping of the pump causes a severe deterioration of
its useful life.
Another disadvantage of this type of system is the time wasted by
the loader as it cycles through a station which does not need to be
loaded.
Accordingly, it is an object of this invention to provide a vacuum
loader with a plurality of loading stations which does not waste an
excessive amount of time while cycling through a filled hopper.
This is accomplished through the use of a two-speed timer to
control the entire cycling operation. Alternatively, a single speed
timer operating at the higher of the two speeds could be employed
if it is used in conjunction with magnetic braking. The two speed
timer operates at one speed while loading and blowing back on each
station, and switches to a higher speed while it is searching for
another station which needs loading. When it finds a station that
needs loading, it then switches to the slow motor and proceeds in
the loading operation. Thus, unlike conventional, single, slow
speed timer systems, where, even when a station did not need to be
loaded, the timer spent the equivalent period before going on to
the next station, the new system searches at a much higher speed
than can be used for loading and thus a station not needing to be
loaded is passed very quickly resulting in a great saving of
time.
Alternatively a single high speed motor can be used to move the cam
at the higher of the speeds. It is still used to actuate the same
switches. When a station is to be serviced, a magnetic brake is
applied, thus allowing a station to be loaded or blown back. The
motor is of the type with a built in brake, which is urged into
braking contact with the armature of the motor by a spring.
However, during operation of the motor, the magnetic field formed
by the current flowing in the coils of the motor exerts a force on
the brake and thus maintains it in its disengaged position, until
the current is stopped, whereupon the motor is stopped immediately
by the brake. A motor which would perform this purpose would be,
for example, the 25 R.P.M. motor marketed under the tradename
Dayton, stock number 3M257.
It is a further object of this invention to blow back each station
separately without the necessity of starting and stopping the pump.
This is accomplished by the use of a vacuum pressure diverter valve
which reverses the air flow through the system. Thus the separate
blow back of each station is accomplished without the attendant
excessive wear and tear on the pump that would result from stopping
and restarting it.
Reference is now made to the drawings accompanying the
application.
FIGS. 1A, 1B and 1C, taken together are a schematic representation
of the electrical control system of the present invention;
FIG. 2 is a front elevational view of the search module assembly of
the present invention.
FIG. 3 is a transverse sectional view of the search module
assembly, taken along lines 3--3 of FIG. 5;
FIG. 4 is a transverse sectional view of the search module
assembly;
FIG. 5 is a longitudinal sectional view of the search module
assembly along lines 5--5 of FIG. 4;
FIG. 6 is a transverse sectional view of the vacuum pressure
diverter valve;
FIG. 7 is a longitudinal sectional view of the vacuum pressure
diverter valve showing actuation of the valve by its operator
solenoid;
FIG. 8 is a schematic representation of the system of the present
invention;
FIG. 9 is a schematic representation of the air flow circuit within
the vacuum pressure diverter valve during the blow back part of the
cycle of the system illustrated in FIG. 8.
Referring now in greater detail to the drawings, FIGS. 1A, 1B and
1C taken together and joined at lines A-B, and C-D form a complete
schematic diagram of the electrical control circuit of the search
module.
In the single motor arrangement, the slow motor would be removed
and the electrical connection shown as broken line 89 illustrated
in FIG. 1A and B would be added.
Power to the machine is supplied by power source 1, connected to
transformer 2 which supplies the system with a control voltage of
110 volts. Pilot light 4 indicates when the unit is energized.
Control circuit protection is provided for by fuse 8. Overload
protection is provided by circuit breakers 6 and 7.
A single pole switch, of which switch 9a is an example, performs
the function of activating its corresponding station. If the switch
is open, the station will be disabled and will not be loaded. When
switch 9a is closed, however, the circuit is now connected to
hopper fill switch 10a. If the hopper fill switch is closed, thus
indicating a need for material, current is sent to the coil to
relay 11a, closing its normally open contacts 13a. The coil of
relay 11a is connected in parallel with the contacts of search
switch 12a. When relay 11a is energized, its contacts 13a send
current to normally closed contacts 14 of relay 16 thus passing the
current to search motor 15.
Referring to FIGS. 1, 4 and 5, microswitches 12a-12h, 23a-23h,
25a-25h, 28a-28h and 30a-30h, `are mounted on bolts 153a-153h and
154a-154h which are fastened to circular plates 151 and 115. The
push buttons of the microswitches are depressed by push rods 43
situated in the guide bores 131 of body 128. Cam 41 is mounted on
armature 42. push rods 43 are depressed by the cam-armature
combination as it rotates inside a central bore 127 in body
128.
Search motor 15 drives the armature of the search module assembly,
illustrated in FIGS. 3 and 5, at the faster of its two speeds. The
higher speed is attained due to the fact that the driving gear 91
used by the search motor in driving the armature is larger than the
corresponding timer motor gear 92.
When cam 41 mounted on armature 42 closes the normally open
contacts of search switch 12a current is sent to the coil of relay
16. Relay 16 is then activated thus opening its normally closed
contacts 14 and closing its normally open contacts 18. The opening
of contacts, 14, stops the search motor 15. The closing of contacts
18 supplys the rest of the system with operating current.
Due to the cam's shape, normally open switches 23a and 25a are
closed which is their position for loading. The pump is thus
started and begins pulling a vacuum on the system.
When microswitch 23a is closed, current is sent to the coil of load
timer 24a. The contacts 17a, of load timer 24a receive current from
the closed contacts 18 of relay 16 which is activated during this
part of the operation. Valve 26a must be open for loading to occur.
Alternatively, it might be noted here that valve 26a may be put in
the material line. During loading, therefor, switch 25a is closed,
sending current to the coil of loading valve 26a, which may be a
common diaphragm type valve, for example, the type manufactured
under the trademark ASCO, No. X821580, and also its pilot light
27a. This pilot light is located at a remote point on the surface
of the loader unit where it is easily visible to the operator of
the unit.
When timer 24a is activated, its contacts 17a close and send
current to the contacts 20 of relay 31. The contacts 20 apply
current to the slow motor 21. It will be appreciated that motor 21
would not be used in the system of my invention where a single
motor unit is utilized. This motor drives the armature slower due
to the fact that its gear 92 is smaller than the corresponding gear
91 of the fast motor. The slow motor then moves the cam 41 a short
distance into position for the second part of the operation. As the
cam moves slowly forward, the predetermined cut in the cam allows
the push rods 43 to open switch 25a. Thus, switch 25a denergizes
the loading valve which was opened at the time the search motor 15
located mircoswitch 12a and activated switches 23a and 25a.
At the same time that switch 25a is opened, cam 41 closes switch
28a sending current to solenoid 29 which rotates the air diverter
valve causing the air circuit to reverse, thus blowing back the
filter 45 in the vacuum hopper 46. The same current which drives
the solenoid 29 actuates relay 31, opening its normally closed
contacts 20. This diverts the current to contacts 19 of timer 32.
The coil of timer 32 is also fed current from switch 28 at this
time. This causes the slow or timer motor 21 to wait till blow back
has completed its job.
Due to the construction of the valves, it is necessary to have
switch 20 energize all the valves of the load cycle except the one
being blown back in order that they stay closed. When relay 31 is
activated, its normally open contacts 33 are closed sending current
to two-position microswitch 30a. In this position, blow back pilot
34a will light up. Contacts 33 of relay 31 send current on a
parallel circuit to all station valves. This operation is necessary
due to the fact that the valves used require current to remain
closed while pressure is applied and also require current to open
under a vacuum.
When timer 32 times out, its contacts 19 close, thus causing the
slow motor 21 to rotate the armature 42 moving the cam 41 to a
position allowing all microswitches to be open.
Assembly of the module is accomplished by mounting spacers 101 to
the top side of base 100. The cover base ring 104 is then mounted
on spacers 101. Spacers 105 are mounted on the base plate with
bolts 102. Mounting plate 124 is mounted on spacers 105 with bolts
135. The relays, the motors and other parts of the electrical
control circuit are mounted on plate 124. The motors are mounted
allowing their gears 91 and 92 to engage the drive gear 106.
Spacers 116 are then mounted on plate 124. Plate 115 is then
mounted on spacers 116. Body 128 is then mounted on plate 115 with
screws 130. Next, cam 41 is installed in armature 42. The two
bearings 109 and 137 are mounted on armature 42. The cam and
armature are then inserted in body 128. Gear 106 is mounted on
armature 42 between plate 124 and plate 115. The bearing 109 and
holding plate 108 are installed on the armature before the gear
goes on. Bearing 137 is then mounted on the armature along with top
bearing holding plate 118. Station indicator 119 is then secured by
bolt 139 to the end of the armature which has a threaded hole at
its end. A dial plate 119a is secured to the top surface of bearing
bolder 118 for the purpose of visually indicating which loading
station is operating.
To install push rods 43 you insert them into bores 131 drilled into
body 128. Microswitches 12a-12h, 23a-23h, 25a-25h, 28a-28h and
30a-30h are then mounted on bolts 153a-153h and 154a-154h which are
secured to plate 115 and ring 151. When installing the
microswitches, it is necessary to make sure that their activating
pins are over the bores 131 in body 128, thus insuring their
activation by push rods 43. Ring 151 is secured to body 128 by
screws 123. Bolts 153 and 154 are secured with nuts 114. The
assembly is now ready to be wired as illustrated in FIG. 1. After
being wired, transparent cover 121 is placed over the assembly and
is secured by screws 134 which go into threaded holes in the module
cover 104. The top, module cover lid 122, is then secured to module
cover 121 by screws 141 which are screwed into threaded holes on
the module cover 121.
Referring now to FIGS. 6, 7, 8 and 9, valve 29a is designed to
allow selection of the direction in which air will flow in duct
203.
During loading, the solenoid 29 which operates the valve 29 is not
actuated and the air circuit is that indicated in FIG. 8. Of
course, it is understood that the air circuit shown in FIG. 8 shows
connections to only one of the loading stations. Duct 205A goes to
the remaining stations. Electrical connections from the search
module assembly to the various remaining stations are also made in
the manner illustrated in FIG. 8. A vacuum is created inside
chamber 46 and material is drawn through duct 206. The vacuum acts
through duct 201, valve 29a, duct 205, actuated and open valve 26
and ducts 203 and 206. Material is thus drawn into the chamber
where it collects and is discharged upon command. When the material
collects to a predetermined point, thus indicating that there is no
need for material, air is drawn out of the system through duct 204
and valve 29a to muffler 57.
When it is desired to reverse the flow of air in the system to blow
back the filter 45, the operator of the valve, solenoid 29, is
actuated. This causes valve rotor 44 to change position, thus
altering the air circuit. The air is drawn into the air circuit
through muffler 57 and goes to chamber 46, where blow back is
accomplished.
In order to assemble the valve, bushing 62 is inserted into front
plate 61. The front plate 61 is then fastened to the valve body 63
by screws 60. Shaft 47 is then inserted through rotor 44. The rotor
44, in turn, is placed in valve body 63 so that the shaft 47 is
protruding through front end plate 61. Rear bushing 49 is then
inserted into rear plate 68. Screws 69 are then used to fasten
plate 68 to valve body 63.
The multi-station loader as hereinabove described exhibits several
advantageous features not found in prior art devices. It has a
rapid search feature and thus decreases time lost between stations.
Also unlike conventional systems, very little time is lost if a
station does not need filling. For example, if in an eight station
system one station is not calling for material, the loader will
behave as a seven station system with a consequent further
reduction in total time required to service the remaining stations.
Additionally, the system described above saves wear and tear on the
pump in that the pump does not have to be reversed for the blow
back part of the operation. This also results in an additional
contributing economy to the overall time saving.
It is understood that the form and design of my invention, as shown
and described herein, are to be taken merely as exemplary of the
same and that various changes and modifications in the shape, size
and arrangement of the components may be made without departing
from the spirit and scope thereof as defined in the appended
claims.
* * * * *