Bulk material feeder provided with internal cleaning mechanism

The bulk material feeder of the present invention, because of the need for cleaning the inside of the feeder, jets out pressurized clean air into the equipment. The air is supplied through the piping used to supply resin pellets and nozzle to carry out the cleaning action, utilizing turbulent flow generated when the air current jetted out collides with baffles installed in the equipment. The air and pellets are easily aspirated and cleans fines adhered to internal walls of the hopper since, naturally, resin pellets remaining in the equipment are destroyed by the turbulent flow. Also resin pellets are destroyed a little by the impact when colliding with internal walls of the hopper, and due to other causes. Residual pellets aspired to the outside and fines adhered to the inside are collected, and internal cleaning can be accomplished in an extremely short time. A bulk material feeder is thus provided with an internal cleaning mechanism.

BACKGROUND OF THE INVENTION 
The present invention relates to a bulk material feeder constituted such 
that, in particular, a cleaning mechanism of a loader inside is provided 
inside the feeder. The invention is related to a bulk material feeder (in 
general referred to as loader) used to supply plastic materials for 
molding, in an adequate quantity, to a plastic molding machine. 
In carrying out the plastic molding, it is widely known to employ a bulk 
material feeder, called, in general, a loader, as a unit to feed materials 
for molding to a molding machine. 
The above-mentioned bulk material feeder is known to be public and is 
combined with a plastic molding machine, concretely, as exemplified in 
FIG. 9. 
Such units are constituted by an aspirator, composed of a filter 1 and a 
blower 2, a molding machine 3 and a material hopper 4, a target tube 
section 5, a bulk material quantity detection sensor 6, a cyclone 
separator 7 and, a material tank 8, etc., as a bulk material feeder. 
The filter 1 and the cyclone separation 7 of the above-mentioned aspirator 
are linked by a suction pipe 11, and the cyclon 7 and the material tank 8 
are linked by a transportation piping 12. 
The above-mentioned equipment operates as follows: 
First, negative pressure is formed in the section of the cyclon 7 through 
the section pipe 11 by driving the blower 2 installed in the aspirator. 
Resin pellets 9 as plastic material are aspired and transported, together 
with the air, through the transportation piping 12, and reaches the 
section of the cyclone separator 7. 
Resin pellets 9 are aspired from the material tank 8 together with the air, 
since they have proper weight. The pellets are separated from the air in 
the cyclone separator 7, dropped, stored in the material hopper 4 on the 
molding machine 3 through the target tube section 5, and continuously fed 
to the molding machine in the required quantity. 
The supply quantity control of resin pellets 9 is carried out by 
supervising the resin pellet quantity in the target tube section 5 with 
the sensor 6. Part of the raw pellets used is micronized by an impact at 
the time of supply, or for other reasons. This part of the raw pellets 
adheres to internal walls of the hopper, resulting in not easily attaining 
the object of changing of resin materials used by only supplying and 
transporting new resin material pellets. 
As a means to cope with these problems, conventionally, as exemplified in 
FIGS. 9 and 10, many operations to dismantle the section of the hopper 4, 
where fines of raw materials adhered to internal walls of the hopper, are 
required, and, using an air gun 10, fines of resin adhered must be blown 
off by blowing pressurized air on the hopper walls or the surface coated 
with raw resin must be wiped off and cleaned manually. 
In case such a measure is taken, however, in a large-sized molding machine, 
the dismantling and cleaning work required for the equipment is not easy. 
In particular, in terms of the equipment construction, there are many 
places where scaffolding is not good, and so on, and a long time is also 
required for the cleaning work. Also, during cleaning work, the molding 
work must be stopped. Further, effective cleaning is not often able to be 
expected. 
Besides, in case the pressurized air is jetted out so as to produce an 
excessively strong air current, causing strong pressure, static 
electricity is generated inside the hopper. Moreover, there are also 
difficult points because of the adhesion of fines to the inside of the 
hopper, and so on, and there is a limit also in the rise of air pressure. 
SUMMARY OF THE INVENTION 
The object of the present invention is to solve defects the conventional 
techniques have, and to offer a bulk material feeder incorporating an 
internal cleaning mechanism, enabling one to easily attain cleanliness of 
internal walls of the hopper in the bulk material feeder. 
The present invention has, as its main point the object of providing an 
improved feeder of bulk materials provided with at least a nozzle to jet 
out air for pressurized cleaning toward the inside of a vessel to supply 
molding materials to the molding machine. An air current is formed in the 
vessel, and inside of the vessel, an internal cleaning mechanism is 
provided. Installed baffles produce turbulent air, or vortex flow and are 
located in positions which exert an influence upon the air current the 
above-mentioned nozzle jets out.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows one embodiment of the bulk material feeder according to the 
present invention for a plastic molding machine. 
The aspirator employed in the present invention is constituted by a blower 
2 provided with a filter 1. Reference numeral 3 denotes a molding machine, 
inside of which an extrusion screw 13 is disposed. 
Reference numeral 5 denotes a target tube, designed so that the material 
supply state and quantity can be confirmed by a sensor 6. 
The spacing between the aspirator and the cyclone separator 7 is traversed 
by a section of pipe 11 which connects the aspirator and cyclone 
separator. 
Reference numeral 14 denotes a material hopper. On wall surfaces of the 
hopper 14, an adequate quantity of nozzles 15 is formed to jet out air 
from the outside to the inside of the vessel. 
The periphery of this material hopper 14 is hermetically surrounded by 
outer rings 16. The inside of these outer rings is constituted so that the 
pressurized air can be freely supplied through a solenoid valve 17 from a 
compressor (not illustrated). 
Further, inside of the material hopper 14, baffles 18 are disposed in 
positions where the air current jets out from each of the nozzles 15. 
Due to the fact that the above-mentioned baffles 18 exist, the air current 
jetted out from each of the nozzles 15 collides with these baffles to form 
turbulent flow. Air cleaning of the inside of the material hopper 14 is 
surely carried out by the thus formed turbulent flow. 
In this connection, the above-mentioned baffles 18 can be fixed inside the 
material hopper 14, and formed so that they can come and go freely from 
the outside of the hopper 14 toward the inside as required, being of 
movable construction as described later on. 
Further, in the transportation piping 12, connected between the cyclone 
separator 7 and the material tank 8, a supply material switching unit 20 
is disposed. 
The material tank 8 is formed by at least two tanks, and is designed so 
that resin materials of different kinds, colors, etc., that is to say, 
resin pellets 9a and 9b can be selected. 
Incidentally, it is also possible to make this material tank 8 a mobile 
type, and replace it as required. 
The supply material switching unit 20 may be constituted by a slide 
manifold 21 to which transportation piping 12a and 12b from the material 
tank 8 are connected, respectively. A suction head 22 connects with this 
slide manifold 21, and rack and pinion 23 and 24 move selectively the 
slide manifold 21 in the horizontal direction by means of a drive motor 
25. 
It is enough that the slide manifold 21 and the suction head 22 have a 
relative movement therebetween. Therefore, the construction shown in the 
illustrated embodiment could be modified so that the suction head 22 may 
be moved. 
Further, it may be clear that many changes are possible also for the 
switching drive mechanism. 
The switching operation of the supply material switching unit 20 
illustrated is carried out as follows: 
In case the unit is switched from a state in which resin pellets 9a are 
supplied, as illustrated in FIG. 1 to a state in which resin pellets 9b, 
the slide manifold 21 is moved by the drive motor 25. The suction head 22, 
matching with the position A corresponding to the transportation piping 
12a, is switched to position O, which is an intermediate position shown in 
FIG. 2. 
While the suction head is in the position O, cleaning work inside the 
feeder is carried out as described later on. 
After ending the cleaning work, the slide manifold 21 is moved again by the 
drive motor 25, and the suction head 22 is switched to the position B, 
corresponding to the transportation piping 12b. 
By such a constitution, in switching the position of the suction head 22 
from the position A to the position B, or in the opposite direction, if 
the suction head 22 is controlled to stop once in the position O, the 
cleaning work can be effectively carried out. 
In this connection, in the state exemplified in FIG. 2, though the position 
O is constituted as the opened state for enabling free aspiration of the 
open air, these mechanisms can also be constituted to perform the air 
cleaning more favorably, including also air cleaning of the inside of a 
transportation piping 12, by introducing the pressurized air current to 
positively form the turbulent flow by using a compressor 26 and a 
turbulent flow generator 27 at the time of internal cleaning. 
Hereinafter, the operation of the cleaner related to the present invention 
will be explained. 
For the supply material switching unit 20, the suction head 22 stops in the 
position O of the slide manifold 21, as exemplified in FIG. 2, by the 
drive of the drive motor 25. 
In this state, the compressor 26 and the turbulent flow generator 27 are 
driven, and the pressurized air forming the turbulent flow is supplied and 
transported through the transportation piping 12. 
On one side, the solenoid valve 17 is opened, blowing in the pressurized 
air from the compressor (not illustrated) into the outer ring 16, and the 
blower 2 of the aspirator is driven. The pressurized air forcefully blown 
in and passed through the injection nozzle 15 rises, turning upward (since 
the lower face direction of the hopper is blocked by molding devices), and 
aspired to the aspirator side. 
The pressurized air jetted out collides with baffles inside of the feeder, 
so that turbulent flow is formed, and each section of the inner wall is 
forcedly cleaned. 
In the construction as exemplified in FIG. 3, where baffles 18 exist inside 
the hopper as in the present invention, turbulent flow is easily formed, 
and the cleaning of internal walls can be effected. 
In a case in which baffles are not installed, as exemplified in FIG. 4, 
even if the nozzle direction, layout position, air pressure to supply, 
etc. are changed in any way, the air supplied inside becomes almost a 
rectified positive current, and sufficient cleaning, therefore, cannot be 
obtained. 
FIGS. 5 and 6 are a plan view and a side view, respectively, showing the 
essential parts of another embodiment of the present invention. In this 
embodiment, four corners of a material hopper 34, cylinder brackets 35 and 
cylinders 36 are disposed. At the tip of each cylinder rod, a baffle 38 of 
a mobile type are connected. 
The above-mentioned baffles 38 are located outwards of the hopper 34 in the 
material supply mode, and, in the internal cleaning mode, they are 
inserted into the inside of the hopper, according to the extension 
operation of the cylinders 36. 
In this case, insertion of all four baffles, one to two baffles, or partial 
insertion of the overall length of baffles 38, and so one, can be 
opportunely selected according to the cleaning conditions. Further, 
accompanying front and rear movement of the baffles (i.e., appearance and 
disappearance of the baffles inside of the hopper), the air cleaning work 
can be carried out also. 
As the result, without hindering the material supply work, it is possible 
to adopt a construction enabling the optimum turbulent flow generation 
effect in the cleaning work. In this connection, the illustration of 
injection nozzle for pressure air introduction was omitted. 
FIG. 7 and FIG. 8 show a different embodiment of the present invention, 
changes the construction of baffles of a mobile type, exemplified in FIGS. 
5 and 6, have been changed to baffles 48 of different construction. 
In this construction, injection nozzles 49 for pressurized air are formed 
in baffles 48 themselves, and by this, the design generates sufficient 
turbulent flow inside the hopper. 
Inside baffles 48, communicating holes, indicated by broken lines formed, 
are in such a way that the pressurized air supplied to an air inlet 50 is 
jetted out from nozzles 49. Further, an inclination section, formed at the 
tip of the baffle 48, has a form matching internal walls of the hopper, 
and in the middle of other end of the baffle, a mounting hole 51 of the 
cylinder rod is formed. According to this embodiment, in forming injection 
nozzles for pressurized air, the degree of freedom for the design is 
increased, and the advantageous turbulent flow generation effect can be 
expected to be more than the simple baffle. 
Likewise, in this case, by using such a construction accompanying the front 
and rear movement of the baffles (i.e., appearance and disappearance of 
the baffles inside of the hopper), or partial insertion of them, and so 
on, a large turbulent flow generation effect can be obtained. 
According to the present invention, when the need to clean the equipment 
inside to supply the raw resin is present, the troublesome line work of 
dismantling the equipment and cleaning work required to wipe the 
dismantled equipment by man power is unnecessary, and the work stoppage 
time accompanied by the change of supply materials can be sharply reduced. 
Further, bad influences, etc., on the peripheral area, caused by scattering 
fines of resin materials caused when the equipment is dismantled, and so 
on, can be eliminated. Proper cleanliness can be attained eliminating 
defects in conventional equipment. 
In this connection, the present invention is not limited to a plastic 
molding machine using bulk materials as in the described embodiment. It is 
also possible to apply the invention to other bulk material processing 
equipment, like food processors, pharmaceutical equipment, etc. causing 
powder mixed bulk materials as raw materials.