Bernd Luebbert «The review of various types of the equipment for packing and dispatch»

General provisions

Now packers should meet in
full to the modern requirements
which are shown to packing installations,
namely:

ƒƒ * completely automatic adjustment under:

• various materials of filling

• different weight of bags

• the different sizes and types of bags

ƒƒ* the maximum cleanliness of bags
ƒƒ* highest weighing accuracy
ƒƒ* automatic closing of valve bags with sealing by
ultrasound
ƒƒ* fast automatic change of a product of filling
ƒƒ* simple and fast cleaning of plant
ƒƒ* high reliability
ƒƒ* practical construction for maintenance
ƒƒ* implementation of the new standard of European
Union OIML R 61 for packing plants
ƒƒ* engineering and execution according to quality
standards DIN ISO 9001.

In addition, the automated packing plant should
join without problems with production process at the
enterprise and consider individual requirements of the
customer. Thus specific properties of a packed material
have crucial importance also.

Various types of packing and dispatch plants

The scope of supply of complete packing and dispatch
plants includes designing, manufacturing, installation
and commissioning. These plants consist of parts
from which according to requirements of the customer
all plant is mounted:

* ƒƒbucket elevators

* ƒƒvibrating screens

ƒƒ* pre-bin with level indicator

ƒƒ* packer

ƒƒ* automatic bag application

* ƒƒbag discharge systems

ƒƒ* spillage return system

ƒƒ* dedusting filter systems

ƒƒ* systems for transportation and removal of the
bags and their loading on trucks and in railcars

ƒƒ* devices for packing of bags on pallets

ƒƒ* pallet packing systems, for example, putting on
of covers from an extensible film

ƒƒ* electronic control system and automation.

Depending on a scope of use and specific filling
properties of different products exists two various
systems of packing: rotary or in-line packers. Rotary
packers have in stock from 3 to 16 spouts, in-line packers
up to 4 spouts. The choice of the packer is mainly
determined by the packing capacity and the available
space for the plant.

ƒƒ* Filling system with the vertically rotating turbine

* ƒƒAir filling system

Turbine packers are intended in practice for free
flowing bulk materials with the maximum diameter of
particles up to 4 mm (for example, cement, gypsum). For
materials with less favorable fluidity and diameter of
particles more than 4 mm (for example, special building materials) use filling systems
which work with using
of compressed air.

Table 1 Performance data of Claudius Peters packing plants, in terms of cement (CEM I) with max 3800 Blaine

Pic. 1 8-spout rotary packer

Pic. 2 4-spout in-line packer

Pic. 3 8-spout turbine packer

Pic. 4 6-spout air packer

Table 2 The choise of the type of packers depending on building materials

Packer with the horizontally rotating turbine

The bag is filled by
means of horizontally
rotating impeller. Conical
material feeding. The
horizontal impeller couple
directly to the motor
with vertically located
shaft of the electric motor.
Capacity of the motor
is 4 kW. The given packer
intends basically for cement
and fine-grained
materials, as for example,
limy hydrate. Advantages
of the given filling
system are shown at the
using of homogeneous
and easy materials.

Thanks to a design
are not used V-belt drive
and appropriately connected
with it structural
elements, such as ball-bearings and a belt drive. For
sealing of filled pot are used scaved-ging air, thanks
that is possible to work without greasing for sealing
and there are no material pollution. The given system
is simple and almost does not demand servicing. A current
consumption low. Also the given type of the packer
in addition provides frequency-controlled turbine
speed and wear-resistant design of turbine.

Pic. 5 Horizontally rotating turbine impeller

Packer with the vertically rotating turbine

The bag is filled by means of vertically rotating
impeller. Conical material giving. Capacity of the motor of 5,5 kW. The vertical
impeller couple by means of
V-belt drive to electric motor
shaft. The given packer intends
basically for building
materials with large grains.
Advantages of the given filling
system are shown at the
using of the mixed materials
from various components.
The vertical turbine is characterized
by very good properties
of self-cleaning. For
sealing of filled pot here too
is used scaved-ging air. The
given type of the packer
provides in addition also frequency-
controlled turbine
speed and wear-resistant
design of turbine.

Pic. 6 Vertically rotating turbine

Air filling system

At pneumatic filling
system the material moves
in the chamber. After filling
the chamber on an input
is closed. For filling
of bags the bottom of the
pneumatic chamber is aerated.
Shut-off flap is activated
pneumatically and is equipped with inflatable sealing collar. The packer
with pneumatic system possesses aeration system
of the continuous, convex bottom of wear-resistant
high-grade steel fabric. Therefore in the bottom
there are no corners and accordingly there are no
dead zones at material aeration. Thanks to an inclination
of the bottom the material gets on air cushion
to a filling pipe. Therefore filling can be carried out
at small giving of air. The given system possesses
also very good properties of automatic self-cleaning
with pressure shock aeration of the filling duct. The
filling chamber accessible from the material feeding
of the packer to the filling pot bottom. For very
coarse materials pneumatic filling system in addition
equips with the cutter valve.

Pic. 7 Air filling system

Pic. 8 Air packer prechamber

Pic. 9 Sealing of the valve bags by ultrasound

Modular design of packers

Modern packers should be integrated easily with
other equipment involved in production process. It becomes
possible thanks to application of modular technologies
which it is simple and for the minimum terms
is built in existing or new plants. Besides, the modular
design of packers has following advantages:

ƒƒ* components easily exchangeable

ƒƒ* extensible circumference for the purpose of
productivity increase

ƒƒ* low maintenance cost

ƒƒ* dust diversion directly at the spout

ƒƒ* dedusting in the packer head

ƒƒ* almost dustfree operation

ƒƒ* frameworks with filling branch pipes and system
of electronic weighing can be easily replaced

Dedusting system

As practice shows has well proved the return
dedusting, when the dedusting air is extracted via
unique exhaust air pipes directly at the spout and
is led upwards the central dedusting hood at the
packer head. From here, the air flows directly to the
main filter system. Consequently, the arising dust
quantity is minimized after filling procedure and an almost dustfree, environmentally friendly operation
is ensured

Ultrasonic bag sealing

Stringent requirements to cleanliness, when storing
and handling individually packed bulk materials,
have led manufacturers of packers to develop ultrasonic
welding technology for bag valves. Here, the
valve is sealed hermetically after filling of a bag and
ingress of dust is excluded.

The special valves are internally coated with a
fusible synthetic material. For welding, the valve is
clamped between the sonotrode and the anvil. At the
same time, a generator is creating ultrasonic vibrations
which are transmitted to the fixed valve by the
sonotrode. The heat arising from the ultrasonics forces
the synthetic material to melt – the valve is glued.
Subsequently, the bag is fed to the bag discharge.

Advantages of ultrasonic bag sealing:

ƒ* Locking rates almost 100%
ƒƒ* Shortest locking times
ƒƒ* Welding directly at the module
ƒƒ* Maintenance-friendly structure
ƒƒ* Protects the filled material from moisture and
environmental impact
ƒƒ* Subsequent plant components remain clean

Bag handling

Depending on application sphere there are various
systems of bags capture: from a simplified bag discharge
belt conveyor with subsequent cleaning of the
bags right up to the removal of under or over-weighted
bags with the following separation.

Pic. 10 Different bag discharge systems

Pic. 11 Palletizer with empty pallets magazine and bag conveyor

Pic. 12 Rear loader for open trucks

Thanks to using of completely automated devices
for application are provided an even application performance
with less operating staff. With a capacity of
up to 4500 bags per hour, empty bags can be fed to the
automatic applicator head by different methods:

ƒƒ* out of cassette magazines for bundled bags
ƒƒ* out of reel magazines in single or double roller
design providing replacement of reels in operating
conditions of packaging

A specially constructed turntable allows a variable
arrangement of the bag magazine and facilitates the
subsequent installation into an existing packing plant.
The bag applicator is suitable for most different bag
sizes and specifications. The changeover to the respective
size can be achieved automatically.

Modern automatic bag applicator should possess
following characteristics:

* ƒƒFeeding capacity up to 7500 bags/h

ƒƒ* Feeding of cassette magazines in standard
lengths of 3 m, 5 m or 7 m.

* ƒƒFeeding of single reel magazines or double reel
magazines

ƒƒ* Automatic bag size adjustment

* ƒƒLift for bag bundles is possible

* ƒƒAll bag sizes and types customary in the trade
applicable

ƒƒ* Free access to loading

Besides, there should be a possibility to load bags
separately into open or closed trucks, on vessels or in
railway wagons and to made available for dispatch via
palletizing systems with modern transportation fallback
systems. For the protection of prepacked building materials,
a film safeguard is considered to be standard today. It
means that modern packing plants should be in addition
equipped by devices for winding, stretching or shrinking.

Integrated independent weighing systems, automation and control

Each filling module in the modern packing plant
should be equipped by own independent weighing electronics. These weighing systems are connected
externally via a data bus with central control system.
From this central control system, the operating staff
can transfer individual control parameters for the
different types of products to the weighing electronics
by keyboard. This also allows a pursuance of the
different metering procedures at the monitor. All
functions are reflected in not coded text, is thus possible
online — adjustment in operating conditions of
the packer.

The basic functions of the central control system
concern:

ƒ* Choice of bulk filling weight

ƒƒ* Indications of current weight: or any separate
module, or for all modules

ƒ* Adjustment of filling parameters for each
weighing module

* ƒƒCalibration of scales

* ƒƒTracing of all dispensing process

The weighing electronics of each module autogenously
controls the metering course in the following
phases:

Area I: Bag identification and zero taring.

Area II: Start the coarse flow metering under
permanent supervision of the filling flow quantity.

Area III: Fine flow metering for maintaining
high weighing accuracy.

Area IV: Check weighing with simultaneous
ascertainment of the fine flow and after-run
quantity. Resulting from this, optimization of
the switching-off points from a rough stream on
a thin, exact stream.

Area V: Bag discharge

Control desk can be integrated into a central
guidance system through different data transmission
systems. Thanks to installation of special programs on
data processing the control desk can be shown all the
gathered data from each of the individual modules as
a statistical evaluation graph and tabulated on one
computer.

Conclusions

Thus, modern packing plans on the one hand
should represent the difficult modular system capable
without effort to be integrated with existing
production process at the enterprise, and on the
other hand, to consist of a considerable quantity
standardized and each interchangeable details. Besides,
modern packing plans should be developed
taking into account individual requirements of
the customer and consider specific properties of a
packed material.

Thus, modern packing plans on the one hand
should represent the difficult modular system capable
without effort to be integrated with existing
production process at the enterprise, and on the
other hand, to consist of a considerable quantity
standardized and each interchangeable details. Besides,
modern packing plans should be developed
taking into account individual requirements of
the customer and consider specific properties of a
packed material.


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