Note: Descriptions are shown in the official language in which they were submitted.
z~
The present invention relates in general to
hopper-type containers, and more particularly, to forming
and handling a slurry and solutions in hopper-type railroad
cars.
S For certain material~, storage and discharge
thereof in slurry form has many advantages over storage and
discharge thereof in dry form. For the'sake of convenience,
a generic term "liqui~ied mass" will be used to include
both a slurry and a solution. However, no limitation on the
10 scope Oæ the in~ention is intended by this terminology, and
such is being employed only for the convenience thereof. In
some instances, transportation in slurry form'may also be
advantageous over transporta~ion in dry form. Thus, it is
quite common for many materials to be stored and discharged
15 in slurry form.
'Generally, a slurry is formed in a container by
inikially loading material in dry form into a contain r,
then liquifying that dry material by pumping a liquid into
the container and mixing that liquid with the material while
20 sometimes adding air in ~he la~e stages of agitation~
If the liquid is not thoroughly mixed with the
initially dry material, t~e slurry has non-uniform propei ies,
such as density, consistency, and the like. Such a non-
uni~orm slurry causes many problemc; in handling and discharge
25 of that slurry material. While hiqh pressure liguid
introduction into the container may help somewhat in the
mixing steps, this method is not entirely satisfactory.
The in~entor is aware of slurry unloading systems,
such as that disclosed in U.S. Patent Nos. 3,512,B42 and
30 3,3787387~ In U~S. Patent No. 3,512,842, air is discharged
into the bulk material. However, in systems such as that
disclosed in the just~mentioned patent, the air discharge
apparatus is simply a plurality of pipes extending upwardly
into a hopper. There is no device capable of discharging
35 gas at or very near the` ~ottom of the hopper, and in a
manner which e~ficiently mixes and fluidizes the matarial.
~erel~ discharging air into the body of such material is not
sufficient to adeguately ~luidize that material, or to
fluidize the ~aterial near that location on the hopper used
,~
as an inlet for liquid and/or an exit for the slurry or
solution. Furthermore, there is no provision in U.S.
Patent 3~512,8~2 for coupling the liquid and air lines to
promote efficient fluid handling to and from the hopper.
The device disclosed in U.S. Patent No. 3,512,842
thus is susceptible to compacting of the dry product,
which may resuit in product lumps into which liquid will not
penetrate. Such lumps are detrimental to a slurry or
solution handling method.
Thus, the applicants are not aware of any means or
method for transforming into slurry form an initially dry
product which is to be stored and handled in slurry form in
a hopper-type container, and particularly in a hopper-type
railroad car, which is thorouyh enough to completely assure
15 the formation of a slurry which is consistent and thoroughly
liquified. The present invention is embodied in a means and
method for ènsuring the formation of a consistent and
thoroughly liquified slurry or solution.
The present invention relates to apparatus and
method for thoroughly li~uifying, mixing and agitating a
product which is to be stored and/or discharged and~or
transported in slurry or solution form from a hopper-type
container, and particularly, a hop~per~type railroad car.
In accordance with one aspect of the present
invention, there is provided a hopper-type container
comprising: a container body having a hopper for con~aining
a product to be ormed into and handled as a slurry or
solution; a gas induction system or inductii~ ~as into the
30 container body, the gas system including an inlet conduit
for connecting a source of gas to the container body, an
aeration device mounted on the bottom of the container body
hopper, the aeration device having gas discharge means located
closely adjacent the hopper bottom for discharging air into
35 the container body adjacent the hopper bottom, and a conduit
connecting the aeration device to the inlet conduit, a liquid
handling system connected to the bottom of the hopper for 'J
conducting liquid to and from the container body hopper from
a 1iquid source and conducting a slurry or a solution from
the container to a slurry or solution handling system; and
cross-over valves connectiny the gas induction system to
the liquid handling system for introducing gas into the
container body through the liquid handling system.
A preferred aeration device for use in the container
is disclosed in U.S. Patent No. 3,929,261, issued to Keith F.
Solimar on D~cember 30, 1975 (hereinafter re~erred to as the
Solimar patent~. Details of the preferred aeration device
will not be herein presented, and attention is directed to
10 the referenced Solimar patent for a full description and
I discussion of those details.
I For ~he sake of convenience, the invention will
¦ be discussed with particular reference to a railroad car.
I However, other hopper-type containers can be used without
15 departing from the scope of the present invention~ The
, sinyle system embodying the present invention which can be
¦ used both for unloading a product dry and in homogeneous slurry
form adds considerable flexibility to a hopper-type rail car.
In accordance with another aspect of the invention,
20 there is provided a method of forming and handling a slurry
or solution in a hopper-type ~ontainer, including the
steps of: placing a quantity o clry material into a container;
forcing gas through the dry mater~.al to agitate the dry
material; continuing to agitate the dry material by forcing
25 gas thereinto whilè simultaneously liquifying the dry material
by forcing liquid through the material; and agitating and
mixing the liqui~ied material to produce a liquified mass
having a consistent composition~
~he thorough aeration of the dry product, the
3Qliquified product and the slurry effected in this procedure
ensures a slurry which is consistent. The consistency of
a slurry handled is much greater than the consistency of
the slurries handled accordingto theprior art known to the
applicants.
¦ 35 Th~ liquid used to form a slurry can be supplied
! from an external source in any suitable manner, and the liquid
¦ handling system may include other elements, such as, for
i example, a standpipe arrangement wherein liquid from a
container is withdrawn and handled during ~ormation of the
' ' '
slurry, or elements for circulating liquid through an external
pump and back into the car. In the interest of clarity,
the exact nature of the liquid circulation system used in
conjunction with the liquid of the car will not be discussed.
It is to be emphasized, however, that a suitable liquid supply
system is included within the teachings of the present
invention.
A plural hopper railroad car embodying the apparatus
of the invention can also include means for recirculating
slurry from one hopper to another without the use of a
standpipe or other similar device. In such an emodiment, the
discharge apparatus on the hoppers of the car include valves
and hoses which can be configured for fluidly oonnecting t~e
hoppers to a main dischargs manifold in a manner such that
the aforementioned hopper-to-hopper slurry recirculation can
be carried out when desired.
The present invention is described furt-her, by
way of illustrations~ ~ith reference to the accompanying
! drawings, in which:
Figure l is a plan view of the bottom of a hopper
used in a hopper-type railroad car provided in accordance
with one embodiment of the presen1: invention;
E'igure 2 is a view taken along line 2-2 of Figure l;
~lgures 3 to 6 illustrate'the configurations'
of the elements associated with a hopper~type railroad car
during the various steps involving the formation and handling
of`a slurry or a solution following the procedure of the
present invention;
~igure 7 shows a plan view of an embodiment of the
invention used for discharging bulk material in dry form;
Figure 8 is an elevational view of the e~bodiment
of Figure 7;
Figure 9 is an elevational view of a portion of
the embodiment of Figure 7i
Figure lO is a partial view of the embodIment
of Figure 7; and
Figure ll is an elevational view of an alternative
form of a standpipe.
.. ," ,
~o~
Referring to the drawings t shown in Figures 3 to 6
is a hopper-type railroad car 10 having the usual wheel
assemblies 12 supporting a chassis 14. The car 10 includes
a plurality of hoppers 20 each of which is formed by downwardly
5 converging hopper walls 24 to form generally conical hoppers
for storing product P therein. The drawings show three hoppers,
however, more or fewer hoppers can be used without departing
from the spirit and scope of the present invention. It is
also noted that car 10 is shown only schematically as the
10 general and overall makeup of that car does not form part
of the present invention. Thus, partitions, and the like,
are not shown in figures, but it is to be understood that
such general equipment is considered to be part of the car 10~
The car 10 also includes a plurality of normally-closed hatches,
15 or manholes 26, each having the usual manhole covers 30 thereon.
A relief valve 40 is noted on the top 42 of the car body 44.
Referring to Figures 1 and 2, it is seen that the
hoppers each have a lower section 5Q which includes a sloped
wall 52 and a horizontal bottom 56. The wall 52 has an
20 annular flange 60 which is attached to the hopper wall 24 by
a coupling brace~62 and fastening means, such as bolts 66.
An annular gasket 68 is interposed between the brace 62 and
the flange 60 to ensure tight sealing of the lower section
50 to the hopper wall 24.
As above-discussed, to facilitate proper stOrage
and discharge of product P, gas and liquid flow systems are
provided. The gas is preferably air, and the liquid is
preferably water, but other fluids can be used without
departing from the scope of the present invention. An air
30 system 70 includes a plurality of aeration devices 100
mounted on the lower section wall 52 at a plurality of spaced
locations. The aeration device 100 is fully disclosed in the
referenced Solimar patent, and attention is directed thereto
for a complete discussion thereof. It is here noted that the
35 devices 100 discharge air at or near the bottom of the
hopper so that air efficiently fluidizes, and maintains
fluidized, the product, In this manner, even that product
located immediatley adjacent the ~opper bot~om will be
adequately fluidized. Thus, no clumps, or dry volumes will
40 be present in the product.
2:~L
An air manifold system 110 includes an air inlet
hose 114 connected to one of the aeration devices for
conducting air from a suitable source (not shown) to the
aeration devices. The aeration devices each includes a double-
5 port inlet chamber 122 and are fluidly interconnected by aplurality of hoses 124 coupled to the inlet chambers of the
devices 100 by hose clamps 126, or the like. The inlet
chambers have coupling means 130 thereon for receiving the
hoses. As discussed in the aforementioned patent,
10 air supply to each of the aeration devices is discharged
outwardly thereof into the hopper in a prescribed manner.
As shown in Figure 1, the hopper can include a
cleanout 132 if suitable, however, such an element is not
an ess~ntial part of the system herein disclosed ~nd is shown
15 i~ Figure:l only for the sake of convenience.
A liquid flow system 14Q includes a conduit 150
connected at one end thereof to the lower sec~ion 50 as shown
in Figures 1 and 2 and has a connecting flange 152 on the
other end thereof~ As shown in Figure 2, a portion of the
20 lnwer section bottom forms part o an end 156 of the conduit
L50. According to the flow directi.on, end 156 is either an
inlet end or a discharge end. Su~l positioning increases
the efficiency o liquid flow into and out of the conduit 150.
~he usual pipe and hofie hangers ancl other supporting
25 equipment are also included in the fluid systems herein
disclosed, but.are not shown for the sake of convenience.
As ~est shown in Figure 3, the air ~low system
110 includes a main air inlet line 160 fluidly connec~ed to
a main air inlet hose 162 by suitable couplings, such as
30 coupling 164 and a check valve 166. The air line 160 is
preferably a 3 inch line. The control valve i5 used to
regulate air flow through the system. A further ~low
regulating valve 168 is mounted on the air inlet line 160.
The individual hopper air flow systems are fluidly connected
35 to the main air inlet line 160 by couplings, such.as coupling
172 which can be a tee, or the like~ ~ lock nut, or like
fastener, couples air inlet hose 114 of each hopper air flow
system to the coupling 172, and thus, regulated air flow from
a source through control valve 168 and to the individual
hopper systems is permitted Yia air inlet line 160 and the
couplings 172.
A main liquid system 180 includes a main liquid
line 182 fluidly connected to each hopper conduit 150 and
5 having a plurality of control valves 186 thereon. Each valve
186 is located adjacent a hopper for controlling liquid flow
to and from that hopper individually and independently of
the flow to other hoppers, as will be discussed below. The
main li~uid line 182 is also connected to the air inlet
10 line 160, and a main control valve 187 is located to fluidly
isolate and connect the air inlet line 160 and the liquid
line 182.
The liquid system includes a main liquid interface
coupling 188 having a valve 190 connecting the main liquid
15 line, or, as shown in Yigure 3, branches of the main liquid
line, to a suitable liquid system. If suitable, the outlet
valve can be manually controlled via handle 192. A pump is
schematically illustrated in Figure 3 to indicate a motive
means for the li~uid system. In addition, the car has a
20 15 psig pressure capability and can be pressurized to assist
in the discharge of the slurry or solution.
As shown in Figure 3, the discharge line 182 forms
a wye adjacent the coupling 188, ~lereby the li~uid line from
one of the hoppers is fluidly conn~3cted to the liquid lines
25 of the other hoppers. The wye-connection can be placed
anywhere on the containers, but is most conveniently located
adjacent an endmost hopper.
As shown in Figures 3 and 4, a main water inlet
line 194 is fluidly and reI~asably attached at one end
30 thereof to valve 190 and at the other end thereof to a source
of liquid (not shown~, and in this case, water A water meter
196 can be attached to the line 1~4 if suitable~
As shown in Figures 5 and 6, a product line 198 is
fluidly and releasably attached at one end thereof to the
35 valve 190 and at the other end thereof to a suitable product
receptacle (not shown).
Referring to Figures 3 to 6 inclusively, the method
of hanaling material in relation to the car 10 will be described ~-
in detaii.
Q~
Product aeration is conducted with the car elemen$s
in the configuration shown in Figure 3. In the Figure 3
configuration, one of the manholes 26 is open to permit air
to escape from the car, the valves 186 and 187 are closed to
5 preven~ escape-of product P from the hopper, valve 190 is
closed to isolate the hopper from a source of water, and
the control valve 187 is closed to fluidly isolate the liquid
line 182 from the air inlet line 162.
In this configurationl air is pumped from the
10 source, through the hose 162, into line 160 and then into
the hoppar air flow systems 70 via inlet hoses 114. The air
then passes through the aeration devices 100 upwardly into
the product as indicated ~y arrows PA in Figure 3~ The
air discharged by devices 100 passes upwardly through the
lS product, ~nd then out of the open manhole. Product
aeration is conducted as described in the aforementioned
patent, and is continued until the product is suitably
aerated.
The aeration-devices serve to distribute air into
20 the product in a proper manner which aerates the product
in a manner which is much more ef~icient and effective than
in prior art systems as discussed` in the referenced patent.
After the product is sufficiently aerated, a
product liquification step is performed to convert a dry
25 product into a slurry for convenient storage, discharget
or shipment. Product liqui~ication is conducted with the car
elemen~s in the con~iguration shown in Figure 4. In the
Figure 4 con~iguration, the one manhole is still open, and
a water hose is attached to valve 190. It is noted that the
30 water hose is shown in Figure 3 to ha~e been attached in the
product aeration step as well, but in that step, the valve
1~0 was closed. The valves 186 are open and water is
permitted to flow into and through the water line 182 to
the hoppers via conduits 150. The control valve 1~7 remains
35 closed, and-the valves 168 remain open to thus continue
the induction of air into the hoppers via the air flow
systems 70. Thus, bubbles B are formed and air continues to
flow through thë product in the direction indicated by arrows
L in Figure 4. After ~lowing through the product, the air
'
z~
flows out of the car via the open manhole. In this manner,
the product is liquified via ~he liquid system and aerated
via the aeration devices 100 simultaneously.
The liquification step is continued until the product
5 is sufficiently liquified.
The aeration devices serve to infuse air into
the product in a manner which promotes liquification by
keeping the product thoroughly mixed and agitated as the
liquid is being forced into the car. Absent such product
10 fluidization, the product may coagulate or coalesce into
clumps, thus vitiating the liquification step. The aerakion
devices thereby ~romoteliquification so that liquification
in the presently disclosed process occurs much more efficiently
and thoroughly than in those processes known prior to the
15 present disclosure.
A~ter completion of the liquification step, a
product agitation and mixing step is conducted to produce
a proper product density and configuration. Product agitation
and mixing is conducted with the car elements in the
20 configuration shown in Figure 5. In the Figure 5 configuration,
the water hose is changed to a product hose, and the valve
190 is closed to isolate the product hose from the rest of
the system and to thus prevent loss of product during this
step. The valves 186 are open as is the valve 187. The
25 valve 168 is closed to isolate the air flow systems, and air
- is forced from the source through air inlet hose 162 and
thus through the liquid line 182 and into the hoppers via
conduits 150. In this sequence~ valves 168 and 187 are used
as cross-over valves for foxcing air in suitable quantities
3a through the hopper liquid inlet systems ~rom an air supply
system. It is here noted that this liquid system is also
the product discharge system as is discussed herein. Air
flow is indicated in Figure 5 hy arrows A, and flows into
the hoppers and forms large bubbles BA due to the large
35 quantities of air infused into the liquified product via
conduit passage 156. The air influx quantities in the ~
agitating and mixing step are greater than the other previous
steps due to the di~ference`'ih air flow capacity of the liquid
system vis-a-vis th- air f1ow system. The valves lB7 and 168
.
,
.
are used to adjust the amount of air flowing into the
appropriate system. Thus, during the various steps, valve
168 is opened so that the air flows through aeration devices
100 in the Figures 3 and 4 steps with the valve 187 closed,
5 and valve 168 is closed and valve 187 is opened to direct
all of the air into hoppers through open valves 186 in the
Figure 5 stepO The quantity of air is also indicated by
the size of the bubbles in Figure 5 as compared to the bubble
sizes shown in Figure 4. It is noted that, for some products,
10 the aeration using the devices 100 prior to this step may
sufficiently aerate the product so that continued aeration
is not necessary~
The large bu~bles in Figure 5 produce an agitation
`and mixing actio~ of the liquiied product, as indicated by
15 the broken product surface line S in Fisure 5. Air flows
from the car via the open manhole, and moves upwardly through
the car in the direction indicated by arrows AM in Figure 5.
It is noted that, while a hose is shown in Figure 5
as being connected to valve 190, such connection is not
20necessary as the valve 190 is closed. Thus, if the product
is to be stored, or moved aft~r the agitating and mixing
step, the valve 190 may just be closed of~ and free of any
connection downstream thereof.
It is also noted that either the aeration and/or
25the agitating and mixing steps can be conducted during
storage of the liquified pxoduct t:o prote~t a~ainst settlin~
or other similar phenomena which m~ght occur ~uring long
periodsof quiescence of the liquified product. Periodic
aeration and/or agitating and mixing will keep that slurry
3~"stirred up" sufficiently to prevent such settling.
After the agitating and mixing step, the product
can be suitably stored, transportedl or the liXe with the
manholes 26 closed. The product is discharged in a dischargè
step with the car in the configuration shown in Figure 6.
35 The manhole 26 is closed so that air introduced into the
car pressurizes the car. The car has a pressure capacity
of 15 psig, and can therefore be pressurized to assist in the
discharge step. This pressure serves to assist in the
.
'
2~
12
product unloading~ and in a preferred embodiment is 15 psig
5maximum). In the Figure 6 configuration, air is conducted
to the car from a sui~able source ~not shown~ via an air
inlet hose 162', and valve 168 is open so that air is conducted
to the air flow systems 70 of the hoppers. It is noted
that the prime notation is used to indicate a movement of
the car from a loading area to a discharge area, but such
areas may be the same if desired. The valve 187 is closed so
that all of the air supplied via hose 162' is forced through
the aeration devices into the product to maintàin the product
thoroughly agitated without interfering with product discharge
in any way. The valves 186 are open as is valve 190,
thereby fluidly connecting the hoppers to a discharge line 198
via conduits 150 and line 182.
Air flows into the product in the direction of
arrows D in Figure 6. It is also noted that use of air
pressure to unload is optional, and a pump (not shown~
may be used with or without air pressuxe.
While specific elements of a liquid circulation
20 means, such as pumps, and the like, have not bee~ illustrated
in the Figures as being associated with the car, it is to
be understood that such circulation means can be used. For
example, the discharge side of a pump can be connected either
to discharge hose 198 in Figure 6, or to water line
25 194 in Fiyure 3, and the inlet side of the pump can be
connected to a sepaxate fitting (not shown) in the hopper
bottom to circulate liquid from and back to car 10~ A
liquid handling system which includes standpipes, such as
that system disclosed in U. S. Patent No. 3,338,63S, can
30 also be associated with the herein disclosed li~uid handling
system without departing from the teachings of the present
disclosure. If a standpipe is used, liquid in the container
can be circulated out of the rontainer during the formation
of the slurry. Thus, the liquid circulation can occur
35 during the liquifying step, or the agitating or mixing step,
or at any other suitable time. A liquid withdrawn from the
container via the standpipe can be used, stored, ~r circulated
back into the container, as desired.
.
'
13
The aeration provided via the aeration devices
keeps the product thoroughly mixed and agitated to ensure
smooth flow of product into the discharge system via conduits
150. Absent such aeration, product may become clogged in
5 the discharge lines due to a coagulation thereof during
storaga and/or transport. Such clogging may slow the
discharge step, or even stop that step in extreme cases.
Therefore, the aeration provided by the aeration devices
during the discharge step serve to expedite that discharge
10 step.
It is thus evident that in each step requiring
the U5e thereof, the aeration devices promote the efficiency
and thoroughness of such step to a level beyond those
levels attainable-using those methods known prior to the
15 present disclosure. Thus,-the process comprising the above-
described steps loads, mixes, stores and discharges product
in a manner which is much more efficient than heretofore
known processes.
An arrangement for handling dry product is sho~n
20 in Figures 7 to ll~inclusively. As shown in Figure 7, the
hopper bottoms 50 are arranged as disclosed above to inlcude
an air inlet hose 114 connected to an air manifold system 110
which includes a plurality of aeration devices 100. The
devices 100 in the Figurq 7 emobodiment are the same as in
25 the Figure 1 embodiment, and thus are fully disclosed in
the referenced Solimar patent. The air flow from the devices
100 is indicated by the arrows 101 in Figure 10. A conduit
150 is connected to the hopper bottom and serves as a product
discharge line.
As shown in Figure 7~ the air inlet system includes
the main air inlet hose 162' connected to the check valve
166' which controls the flow of air from an air source
(not shown) to the hoppers. A tee coupling 172' connects a
- control valve 187' and a control valve 168' connects air
35 ~upply line 160' to the tee coupling 172' and hence to the
air supply. A hopper close-off valve 300 connects each hopper
inlet hose 114 to the air supply line 160' and can be used to
selectively connect and disconnect each hopper to the air
supply line. The valves 300 are optional and enable the -
., .
o~
1~
system ~o operate with limited air supplies, and/or with
difficult product. The ~alves 300 permit operation o one
hopper at a time. A close-off valve is shown in Figure 10
in the open configuration.
A standpipe 310 is connected to the air line 160'
by a feed line 312 and a tee coupling 314. A standpipe
control valve 318 is located in the feed line 312 to control
the flow of air from the supply line 160' to the standpipe 310.
A product discharge system includes a pipe section
10 320 connecting the control valve 187' to an elbow 324 which
is connected to a second pipe section 326. As in the abovet
disclosed embodiment, the valve 187i is a balancing valve
and balances the air flowing into each of the pipes 160'
and 182' to proper and desired levels. A control valve 330
15 controls the flow of air from the supply into product
discharge line 182l. Each hopper conduit 150 is connected
to a product discharge valve 334 which is connected by a
Y-coupling 338 to the product discharge line 182'.
The product discharge valves 334 control the flow
20 of dry product out of each hopper and can be used to ~hut
off each hopper either temporarily (to, for example, loosen
a plug of product lodged in the hopper discharge line 150,
or the like), or permanently (e.g., after the hopper is
completely empty).
~s shown in Figures 8 and 9, the standpipe 310
includes a vertical section 340 having an exit section 342
located near the top o~ the container 344 to discharge -
pressurizing air 346 into that container, and a blow~down
section 348 located near the hopper bottom 50. The section
30 348 includes a blow-down valve 350 and a vent pipe 352 which
is open to the atmosphere to discharge pressurizing air
346 9 thereinto. Various flanges, such as flange 354,
connect pipe sections together to form a standpipe having a
proper length. The blow-down section 348 is used to relieve
35 air pressure within the container.
~ pair of pressure relief valves 360 and 362 are
positioned in the standpipe feed line r as is a vacuum
relief valve 364. A remote control system (not shown~ can ~e
used to operate these valves, and a lead wire 366 is shown
, .
3l~2~
in Figure 9 to indicate connection to such control system.
A standpipe control valve 370 is connected to the feed line
312 to further control the amount of air flowing into
the standpipe.
An alternative embodiment of t~e standpipe is
shown in Figure 11 and is indicated by the numeral 310'.
The standpipe 310' includes a tilted section 340' and pressure
relief valves 360' and 362' located in the blow-down
section 348'. The blow-down section 348'is open to atmosphere,
10 as is blow-down section 348 to vent air thereto. Otherwise,
the standpipe 310' is similar to the standpipe 310.
Suitable pipe hangers 380 r and other such elements
are also included to properly mount the pipes on the container.
Suitable baffles can also be included to isolate each hopper
15 from the others, if so desired.
The operation of the system shown in Figures 7
to 11 will now be discussed. Normally, only one hopper is
unloaded at a time, and the hoppers are unloaded sequentially.
To initiate unloading, valves 166', 187' and 330 are opened
20 with control valve 168' closed to force air through the
discharge line 182'. The air is initially forced through the
product discharge line into the product collection means,
such as a silo, or the like~ to permit the air moving
de~ices, such as blowers or the like, to come up to working
25 levels. Once these working levels are attained, control
valve 187' is closed and valve l68' is positioned to f1Ow air
through the air supply line 160' and into the hopper air
systems as previously described. Air also flows through
the standpipe in~o the container.
All of the air is forced through the aeratio~
devices 100 to fluidize the productn Once the product is
sufficiently fluidized, control valve 187' is opened
slightly to permit air to flow into the product discharge
line. It is noted that container pressure is generally
35 maintained in the range of 10 to 12 psig, and can be controlled
via the standpipe system.
Once the proper air.flow is established through
both the aeration systems and the product discharge line,
2~L
16
the hopper product discharge valve 334 on the first hopper
is opened. Product from -that first hopper then flows into
the product discharge line and then to the product collection
means.
Product is discharged until line pressure and
container pressure both drop theréby signifying an empty
tank~ or in the case of a hopper-type railcar, an empty hopper.
At this time, the valve 334 of the first hopper is closed,
and the valve 334 of the next hopper is opened, that hopper
10 pressurized and emptied in the manner just described. The
process is continued until all of the hoppers are emptied,
There may be some residual product remaining in
each of the hoppers after the completion of the just-
described process. Each hopper is individually opened to
15 the product line via valves 33~ and each hopper is pressurized
to a fairly high value. Such procedure discharges t~e
residual product from each hopper into the discharge line.
It is noted that on a three hopper car, it is
; preferable to empty the center hopper first, then emptying
20 the end hoppers. In a four hopper car, baffles may be
present to limit product shift, and thus it is preferable to
empty an endmost hopper first, then proceed to the next
adjacent hopper, and so on.
It is noted that air is forced into the product
25 through the aeration devices at all times during the
discharge process. In this manner, the product is thoroughly
fluidized and is therefore efficiently unloaded. The
blow-down sections of the standpipes can-be used to further
control the pressure inside the container. The pressure
30 relief ~alves and the vacuum relief valves in the standpipe
feed line are optional and can be used to direct some, or all,
of the air supply into the container. An operator thus has
extra control valves which can be adjusted to optimize
settings for a particular combination of product and air
35 supply. The air flow established in the product line keeps
the product therein fluidized and moving ef~iciently there-
through. rr
The product discharge valves 334 can also be used
to discharge any product clogged in the hopper discharge
' ' ~ '
,
. . .
~o~a~
17
lines 150. Closingthe valve 334 and pressurizing a hopper,
then popping the valve 334 open will unplug the discharge
line.
The system shown in Figures 7 to 11 can be used in
5 conjunction with either a railroad car or a road vehicle.
As shown in Figure 10, a railroad car will have a hopper wall
inclination angle of about 30 whereas a hopper-type trailer
will have hopper walls inclined at about 45 with respect to -
the vertical. The difference in wall angle results from
10 clearance differences between rail cars and trailers as
well as considerations of container center of gravity~
,
