Cartridges “on demand”: Filled cleanly
They are needed in virtually every office, but no-one really likes to change them: cartridges for digital printing. The cartridge specifications to be produced are as diverse as the colour spectrum. Cartridge users have different requirements when it comes to colour and quantity. The aim of cartridge manufacturers is to produce the different cartridge specifications quickly and cost-effectively – and for as wide a colour spectrum as possible. To fulfil the individual requirements of the customers, the laborious cartridge manufacturing process needs to be largely automated. A complex task, which the Ludwigshafen-based process technicians of J. Engelsmann AG have tackled with the design of an automated system to empty various big bags.
The cartridge manufacturer, which charged J. Engelsmann with the tricky task, produces and supplies customer-specific colour cartridges, which are produced on demand in the relevant corporate colour and required quantity. To guarantee a consistent quality to the customer-specific cartridge specifications, absolute consistency and precision are needed in their production when dosing and weighing out the individual components. The required safety standards also have top priority due to the explosive cartridge mixture. Diverse requirements, which have been imposed on the system construction and Engelsmann engineers. The system solution, which was designed and built by the Ludwigshafen-based technicians and commissioned six months later, was also extraordinary.
Automated but still individual
Equipped with ten big bag emptying stations, the system covers the complete process from mixing the colour to the user-specific filling in individual containers. The system enables the production of customer-specific corporate colours with a high degree of accuracy within a very short space of time. Continuous colour consistency is ensured as a result. Every one of the ten big bag emptying stations is equipped with a chain hoisting system to take up the big bags. A dust-proof connection is established between the big bag outlet and the emptying hopper. Each hopper features a double dosing screw conveyor for coarse and fine dosing. The system is controlled according to colour recipes directly picking up the individual colours at the big bag emptying station with a movable weighing unit carrying a drum.
At each station, the drum is automatically connected in a dust-proof way with the outlet of the dosing screw conveyor and the dosing process is started. It ends as soon as the predefined weight is reached. To prevent residual flow of products, the screw conveyor outlets are pneumatically sealed. After the individual colours have been dosed into the drum, they are carefully mixed by a highly efficient drum hoop mixing unit. After a predefined mixing period, the drum is withdrawn and the cartridge colour is filled into respective containers for distribution.
In terms of safety, the Engelsmann engineers developed a concept based on predefined ATEX zones. In addition to the installation of a demanding electronic control system, leading to redundant design of all mechanical functions, simple, fool-proof handling, smooth surfaces and a dust-proof design characterise the high safety standard of the automated filling system.
The dust-proof connection of the big bags to the emptying stations is a particularly important safety factor to protect people and the environment from the cartridge mixture. An undertaking, which proved to be difficult and above all time-consuming due to the use of different big bags, as the big bags to be conveyed into the station had different lengths of outlet nozzles. The result was a great deal of manual handling until the big bags were connected to the emptying hoppers. Anything but an economical and safe solution.
Connection system for different big bags saves time and money
Economic docking demands reliable and user-friendly solutions that can be adjusted. With JELSafeConnect, the Engelsmann engineers have developed a connection system, with which conventional big bags with different lengths and diameters of the inlet and outlet nozzle (250 to 400 mm) can be quickly connected in a dust-proof manner. Laborious adjustments are avoided as a result. Easy connection is possible within a tolerance of 50 mm.
Furthermore, by using the JEL SafeConnect system, laborious retrofitting can be avoided, for example, if a new customer requires big bags with a larger diameter of the inlet nozzle and the manufacturer has to retrofit the filling head of his filling unit for this. By using JEL SafeConnect, tolerances in the diameter of the inlet and outlet nozzles can be compensated so that different customer requirements can be fulfilled without any laborious adjustments to the filling unit.
The low installation height of the JEL SafeConnect system can especially save effort and costs when used in cramped areas, for example, if a big bag emptying station must be moved to a different site with a lower ceiling height. As an alternative to the expensive shortening of the entire emptying station, using the JEL SafeConnect system is a far more cost-effective solution.
System variations enable a wide range of uses
The JEL SafeConnect connection system is available in two designs: the standard design guarantees dust-free docking of big bags using a pneumatic seal. Here, the nozzle of the big bag is put over a flexible adapter ring, inserted into the casing of the JEL SafeConnect connection and connected to this. By inserting compressed air, the integrated, pneumatic seal expands and fixes the big bag nozzle. An additionally available suction device and shut-off valve prevents contamination of the environment and protects the user from any risks thanks to the control technology.
A further developed design of the standard system is characterised by its expanded uses. This is possible due to a mechanical connection technology, which firmly connects the inlet or outlet nozzle of the big bag to the system. In this connection, a locking device replaces the pneumatic seal of the standard system. This makes the connection system interesting for any users and fields, which do not have a compressed air connection.
To avoid the major manual effort of connecting the different big bags to the emptying hopper, the cartridge manufacturer decided to use the JEL SafeConnect system in the filling system as well.
This meant he was able to significantly reduce the retrofitting times when changing big bags and increase the productivity of the system.
Components of the filling system:
- 10 big bag emptying stations with double dosing screw conveyors
- Aspiration system for dedusting
- Electrical control system with recipe input
- Movable weighing unit with weighing system
- Drum hoop mixing unit to homogenise the colour components