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LIPPERT's new high-pressure casting plant for handles, type HEDG-300-2, will be on display at stand B6 109/210.
This highly versatile, fully automated plant shapes both stout and slender handles according to the high-pressure
casting technique, then demoulds, finishes and cuts them to match the shape of the cup. The handles can be either
immediately matched to the cups or stored in a damp box for attachment at some later date, independent of the
production process. This new type HEDG-300-2 unit simplifies the production of handles, systematically improves
their quality and greatly reduces labour costs through high-level automation.
LIPPERT designed the type 24K45 feed dryer with sanitary fixtures and other large components in mind. The core
characteristic of this new system is its enormous setting density with up to 24 pallet conveying sections through
the dryer, and 1200 stainless-steel pallets (900 x 1200 mm) in the tunnel. This plant offers the following advantages:
- Enormous daily output coupled with outstanding climate-control characteristics
- No transport chains in the dryer
- Substantially lower service connection requirement
- Easy handling and simple logistics thank to robotised loading and unloading
The first few plants have already been delivered to leading producers of sanitaryware.
LIPPERT was awarded a large-scale contract by Roca Brazil for a drying system
(including microwave pre-drying) and a robot glazing system for pressure-cast sanitaryware.
All in all, LIPPERT will be supplying two (2) large channel dryers featuring 16 channels
each, one (1) microwave pre-drying system, and five (5) robot glazing plants. All units are
connected in line by a handling system. Transport of the articles from the pressure casting
plants all the way to kiln-car loading is virtually fully automated.
The plant is scheduled to go live by the end of 2011.
One of Asia’s renowned china manufacturers recently commissioned LIPPERT of Pressath with a
major order for four universal tableware glazing plants for glazing bowls, plates, etc.
The customer is enjoying maximized output, effectiveness and quality thanks to the plants‘
fully automated glazing processes. The plants are running fully automatically in multiple-shifts,
covering all processes from article loading to base stamping to dip glazing all the way to sponging.
Upon leaving the LIPPERT plants, the finished articles are ready for immediate placement on the firing batts.
Adidas just commissioned a new outgoing-goods sorter system from LIPPERT.
Yet another opportunity for LIPPERT’s proven Rota-Sorter® technology to succeed and shine.
Over the next four months LIPPERT will be supplying four additional double sorter systems
to Hermes, thereby increasing the number of Hermes facilities equipped with Rota-Sorter® Technology to a total of 50.
- Processing of return slip from casting benches
- Glaze overspray from spray booths
- Rinsing water from pressure-casting plants
1. Microfiltration – Cross Flow Filtration:
Microfiltration can be classed as a dynamic filtration process for the separation of a medium (suspension).
Filtration is a mechanical separation process.
Separation is based on the principle of mechanical size exclusion (principle of filtration),
i. e. all particles contained in the fluids that are bigger than the pores of the membrane are retained by the membrane.
Driving force in both separating processes is the differential pressure between the flow to and from the filter surface, which ranges between 0.1 and 3 bar.
The filter surface material is made of ceramic.
A distinction is made between micro- and ultrafiltration depending on the different pore sizes and membrane structure, as well as on the substances and
filter materials involved. Filtration through membranes with a pore size < 0.1 µm is generally termed ultrafiltration, while filtration at pore
sizes > 0.1 µm is usually referred to as microfiltration.
A filtered liquid is termed filtrate.
In contrast to static filtration methods, cross-flow filtration systems are capable of clarifying liquids with a relatively high turbid content.
This is achieved by applying a cross-flow of around 2.5 to 3 m/sec. to the membrane, which prevents deposition of turbid particles and fast clogging
or binding of the membrane (build-up of filter cake).
2. Lippert Rotary Filter
2.1. Description of the Process Sequence:
In the filter unit, ceramic filter disks are threaded onto a hollow shaft.
If the pressure chamber is now set to differential pressure (1 to max. 3 bar), the filtration process begins.
The filtrate "flows" from the outside through the filter disks and via the hollow shaft to be discharged into a filtrate collector tank.
By selection of the appropriate filter fineness, certain particle sizes are retained and conveyed into the waste-water collector tank.
From the waste-water tank, the thickened liquid is fed back to the filtration process. The system operates in a closed circuit.
To prevent the build-up of filter cake on the filter surface, the filter disks are rotated and any particles simply flung off.
With the backwash unit, the filter unit is flushed with water.
The rotary filter is based on a modular design, so that it can be simply adapted to different applications.
Image 1, flow chart
3. Typical Applications
3.1. Slip Processing at Casting
To clean casting bench pipes at set intervals, these are flushed with water. On account of the low sediment load, processing of the residual slip contained has so far been a very complex process.
The sediment load can be precipitated in a settling basin. The water is siphoned off and the sediment must be removed at certain intervals.
Filter press operation is limited in respect of processing slip water with a low sediment load (1.05 kg/dm³) and is very work-intensive.
With the rotary filter, the backwash water with a density of around 1.1 kg/dm³ can be used directly, thickened to around 1.4 kg/dm³.
Image 2, densification of slip
3.1.1. Test results
In this case, a filter with a 2.5 m² filter area was used for processing the return slip.
The daily total volume of recycled slip processed in a specific case is approx. 10 m³. The total volume of reusable slip obtained from the recycled product is approx. 3.9 m³/day.
(Rates have to be verified in specific cases. See the start and final density of the slip listed below.)
Image 3, results
3.2. Processing of Glaze-Overspray
Spraying booths equipped with water-wetted impact walls permit the successful recycling of the glaze contained in the water.
As for slip processing, it is possible to process the overspray based on sedimentation and a filter press.
The rotary filter makes it possible to directly concentrate the very low-density water (approx. 1.1 kg/dm³) down to a water density of approx. 1.4-1.6 kg/dm³.
Advantages:
- automatic process flow
- total particle fraction is preserved
- limited space requirement
Image 4, densification of glaze-overspray
3.2.1. Test results
In this case, a filter with 2.5 m² filtering area was used for processing the glaze.
In the case mentioned, it was possible over a 180-Minute period to concentrate 1.150 Liters of glaze suspension with a density of 1.07 kg/dm³ down to a density of 1.62 kg/dm³.
The volume of the glaze with a density of 1.62 kg/dm³ totalled 250l
The daily total volume of glaze suspension processed in the case mentioned is approx. 6 m³. The amount of glaze obtained is approx. 1.9 m³, with a glaze density of approx. 1.6 kg/dm³.
(Rates must be verified in specific cases. See the start and final density of the glaze listed below)
Image 5, results
3.3. Processing of Rinsing Water in Pressure Casting Plants
After every press cycle, the pressure casting moulds are rinsed with water.
For deep cleaning of the mould, mould cleaning agent is added to the rinsing water at certain intervals, with the aim of increasing mould lifetime.
Based on a water consumption of around 200 l/h for sanitary ware moulds, a water consumption of approx. 5 m³/pressure casting bench per day can be assumed.
Advantages:
- automatic process flow
- uniform water quality
- closed circuit operation, no water consumption
- limited space requirement
3.3.1. Test results
With the use of the rotary filter, the water quality remained unchanged over the entire process duration.
The additives in the rinsing water were recirculated in a closed circuit (reduction of the mould cleaning agents used).
Additionally improved plant safety, as in an incident involving hydraulic oil, the oil could be kept separate from the filter medium and did not contaminate the rinsing water circuit.
With the use of a 2.5-m²-filter, a filter rate of around 500 l/h can be assumed for design purposes. (The process temperature is approx. 35°C)
Based on the consumption values listed above, the rotary filter with 2.5-m² filter area is suitable for treatment of the rinsing water from two pressure casting benches.
4. Final Conclusion
The rotary filter presents a cost-and-energy-efficient solution for the ceramics industry.
Applications with aim of recovering valuable substances such as glaze or slip have previously been very work-intensive.
With cross-flow filtration, payback periods of less than two years can be realized in individual cases.
Owing to higher requirements with regard to abrasion, selection of the filter technology is crucial for the lifetime of the system.
With the use of ceramic filter disks, it is possible to uncouple the differential pressure and overflow rate.
This reduces the wear and is reflected in the long lifetime of the rotary filter.
[2009-10-06; 11.00 AM]
  
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