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From the Desk of Hermann Marburger-Theimer


Here our owner, Hermann Marburger-Theimer, is reporting directly from his desk about recent events and news concerning the screen printing market and/or the company Bochonow GmbH!


The new automatic screen washer RotorWasher-RW from Bochonow®

Specific requirements of the industrial screen printing, especially with possible new pastes, adhesives, insulating pastes, etc., ie the partial coating of the screen printing process, led to the development of RotorWasher-RW.

The stringent requirements of the ATEX guidelines of the EU (ATEX Directive 94/9/EC) were considered consistent with the design of the RotorWasher-RW.

Specially arranged flat spray nozzles in the RotorWasher-RW clean both sides of vertically positioned screen printing forms. The washing process uses the proven "high-volume" principle of BOCHONOW®. It provides a nozzle diameter of more than three millimeters (!) for optimum cleaning efficiency, extreme short washing time and low-maintenance operation.

A powerful electric centrifugal pump conveys the solvent from a large tank under the wash chamber into the circulation.
The high flow rate pump allows the use of clog resistant nozzles with large diameters and high cleaning efficiency.
Screen cleaner  as  a  cleaning  medium  with  a  flash point of >55°C and a conductivity of >10-9 S/m must be used.

A drum pump with a  stainless steel pump tube is optional.
The exhaust pump tube is inserted through the stable holding device into the sump of the washing tank. Thus, a residue-free emptying of the tank is possible.
The drum pump can be used also to refill fresh solvent.

A key part of the user-friendly features is the fuel indicator. A float is integrated in the tank containing a visual level indicator, providing safe and reliable signals of the recent amount of solvent in the washing tank.
Control of the remaining amount of solvent is available at a glance.

According to the ATEX directive the exhaust fan was designed to ATEX Category 3. The exhaust fan is installed on the air control box and exhaust air volume ratios between the drying chamber and the door exhaust system  of the washing chamber can be adjusted easily.

Protecting the environment and saving valuable resources are the foundation of the VOC directive, which are implemented in the new BGI 801.
To meet these demands the exhaust system of the washing chamber is prescribed as a door exhaust system. This requirement is included in the construction of RotorWasher-RW.
The exhaust system constantly pulls from the air duct, which is designed around the loading door.
If the loading is door opened, any escaping solvent vapors are immediately removed and kept away from the user.
The drawback of the high solvent emissions by the formerly used chamber extraction systems is passive.

A decisive factor for the cleaning effect of the RotorWasher-RW is the amount of solvent which is sprayed onto the screen per time unit.
By using a nozzle diameter of 3 mm, a substantial amount of screen cleaning solvent is circulated. Even in the smallest model of the RotorWasher-RW the solvent pump provides 10,000 liters per hour. This low-noise solvent pump is performed on all wetted parts in stainless steel 1.4404. As a sealing material high-quality KALREZ® is used exclusively.
For high demands the optional fine filter with stainless steel case and replaceable filter cartridge (25…200 microns) is used on the pressure side of the solvent pump.
We developed a fast venting of the solvent pump. This ensures trouble-free operation of the plant. Even after long periods of empty sequences the system bleeds automatically without manual work!


Reliability and availability of systems are challenges for a modern equipment manufacturer.
The suction and discharge piping of  RotorWasher-RW is performed with compression type fitting.
The  enormous  flow  of  the  wash  pump  is  ensured  by  using  a nominal  diameter of  28 mm.

Special attention was paid to the construction of the screen holding frame of the  RotorWasher-RW.
The inclined suspension is perfect for fast draining and drip-off oft he solvents. The screen holding frame can be designed (as seen in the figure) also for loading a multiple number of smaller screen frames.
The screen holding frame is provided with a continous drip pan, which is brushed off when pulling out the frame. This unique design prevents spillage on the front operator area, while the front entrance to the plant is completely free, because there is no need for a very disruptive, permanent collection device.

After the drip-off time, the still wet solvent screen frames will be removed from the washing chamber and placed in the drying chamber.
As standard, the drying chamber is equiped with 4 slots for the max. screen frame size. On customers request, it is also possible to equip the drying chamber for several smaller screens (see figure).
The drying chamber is continuosly vented with a large amount of air and ensures rapid drying of the washed screen frame.
Because of the separated drying chamber, large quantities of solvent can be saved, because the drying process is carried out not inside of the washing chamber. There by the washing chamber will not dry out!
Another important advantage of the separately designed drying chamber is an enormous increase of throughput of screens. While the wet screen is dried in the drying chamber, additional screen(s) can be washed in the washing chamber simultaneously. Both processes run parallel, to save time!

The newly designed door-locking  system offers optimal user protection.
The easy to use latch system is scanned electronically and  triggers the pneumatic door locking mechanism. This ensures, that the start of the washing process can be done only with firmly closed door.
The pneumatic door lock prevents opening of the loading door during the washing and drip-off process.

The solvent tank is monitored by several devices. Besides the optical tank capacity control (see above) a stainless steel float  EX-switch is integrated to protect the pump from running dry.
A EX-proofed stainless steel temperature sensor monitors the bath temperature and shuts down at a solvent temperature >40°C.

The stainless steel control cabinet is located on the rear of the system and is ready to connect.
Via the digital programming display on the front panel of the control cabinet, the washing and drip-off time can be individually programmed.

The RotorWasher-RW comes standard with a drip-pan. The whole screen washer is in a pan made of high-grade stainless steel with 2 mm thickness, which is fitted with grids in the front area. The grids can be removed easily for cleaning.

A special technique is used to ensure a reliable washing door seal in the wash chamber!
The outer door is pressed into a completely solvent-resistant door gasket. The spring mounted interior door is pressed against the inner doorframe while closing the loading door.
This double structure design allows for a wear-free and secure seal.

The RotorWasher-RW is made of diamond-patterned, high-grade stainless steel. This material is very strong (about 2 mm thick) and is characterized by a highly scratch-resistant and visually appealing surface.
The base construction is extremely stable and can be disassembled for transport.

More information: www.rotorwasher.com

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Our Products

Every modern screen printing workshop or department feature modern and efficient screen printing equipment! No matter if for pre-press preparing of the screens, the printing process, drying of the printed substrates or post-press reclaining of screens - the current Bochonow-programme consists of well-engineered equipment for all applications.

Our Products

Every modern screen printing workshop or department feature modern and efficient screen printing equipment! No matter if for pre-press preparing of the screens, the printing process, drying of the printed substrates or post-press reclaining of screens - the current Bochonow-programme consists of well-engineered equipment for all applications.

Dieses Dokument wurde mit einem Schreibschutz geöffnet, da es durch einen anderen Beutzer gesperrt ist. Durchgeführte Änderungen werden nicht übernommen.