User's instructions for acid baths with rim exhaust, design Polymetaal, models ZR-60x80, ZR-80x100, and ZR-80x120S

1. These acid baths have been designed for the etching process as used by printmakers with copper plates and zinc plates, for which attacking agents such as nitric acid or iron chloride are used.
2. Firstly, the inner bath is filled with the desired acid until the necesary level (normally 1 inch, or 2,5 cm will be enough). Please check if the tap under the bath is closed during this proces. You also need protective clothing when you are handling attacking acids. (a pair of spectacles, gloves, air filter to breathe, etc.)
3. When the bath is filled with acid the ventilator should run to prevent, as much as possible, fumes entering into the printing area.
4. Now the cover can be opened. During the opening of the cover a certain resistance exists; the cover is pushed downwards because of the action of the ventilator.
5. The copper or zinc plate can now be laid down in the bath, with help of a gripper or something similar.
   With the cover open and the ventilator running, a stream of air develops towards the edges (rims) of the inner bath. The acid fumes, heavier that air will follow this air stream and enter into the openings between the inner and outer bath. At that moment there is a curtain of flowing air mixed with acid fumes. To a certain degree this curtain prevents the acid fumes from entering into the printmaking area. However, too much stirring of the air flow must be avoided. So be careful with entering the plate into the bath and taking it out again. Don't make quick moves. Also, close the cover as soon as the proces permits it.
6. It may be necesary, during the process, to open the cover one or more times, to inspect the etching process and perhaps for removing the bubbles on the plate. Try to limit these actions.
7. After the etching process the plate should be taken out of the acid bath.
8. It is strongly recommended to remove the acid out of the bath, when the etching process is finished. This can be done by means of opening the valve (see image) and pouring the liquid into an acid resistant plastic jar that can be closed.
9. It is possible to leave the acid in the bath (if unavoidable) but keep the ventilation system running in this situation.
10. The exhaust side of the ventilator must be connected with the outside air through an acid resistant plastic tubing. The standard diameter of the tube is 12,5 cm (appr. 5"). The air resistance of the whole system must be kept under a certain value. This is the reason that the total length of the tubing may not exceed 5 meters (appr. 15 ft.). If the total length needed is longer, the diameter of the tubing must be increased, or a more powerful ventilator installed. If there is an existing exhaust system in the building to which this acid system can be connected, some parameters must be checked;
    - the total air resistance of the system may not exceed 200 pa (with open cover, and with the assumption that the standard ventilator that comes with the acid bath is the only driving force for the air flow) The capacity of the ventilator is approximately 1000 m3/hour at this pressure (200 pa). (Ventilator motor 0,25 kW, 220 Volt, 1380 rev./min.) If the total air resistance is greater than the abovementioned value then a heavier ventilator has to be used.
11. The gases emitted from the system are diluted by the extra air flow and not dangerous. As the fumes will cause corrosion it is advisable to drain the acid after use.
12. The standard electrical system can only be connected with a contact of 220 Volt/180 Watt. On demand we can supply an electrical system with 110 Volt/180 Watt.

Installatie regulations for the acid resistant ventilator

• The suction and press sides of the ventilator must be connected in a flexible manner to the tubing.
• The demands following DIN EN60204-1 regarding electrical installation as well as electrical protection must be followed. The work switch must be easily accessible.
• By excessive condensation the body of the ventilator must have at its lowest point a hole whereby an exhaust outlet can be connected. Connection must follow the instructions stated.
• At surface temperatures greater than 343K (70°C) protection is required against contact with the ventilator body.

• For the first few months a monthly inspection is required.
  Following checks to be carried out;
  - check the smooth running of the ventilator.
  - check the ball bearing temperature according to the regulations from the manufacturer.
  - if hazardous media are pumped and the ventilator is opened, protective clothing is required.