Operating Instructions
Description, Structure and Functioning
METACAP Spray Gun D/A
Version/Edition July 2008
6-13
6.4
Functioning
Note:
The position numbers refer to figure 1, see chapter 6.2 Structure of the
METACAP Spray Gun D/A, page 6-11.
The METACAP Spray Gun D/A generates the necessary low pressure and
the required high air volume from the compressed air produced by the
compressor and from the ambient air.
The air supply nozzle (1/26) supplies the compressed air into the spray gun,
where it is reduced to approx. 0.3 bar to considerably increase the
compressor-driven air volume with a Venturi nozzle (Bernoulli system),
which is located within the Venturi air converter body (1/25) to take in the
ambient air via suction holes. This air now flows through the completely
hollow interior space of the spray gun body (1/8) up to the nozzle cap (1/2),
where, depending on the respective adjustment of the nozzle cap with
regard to the nozzle (1/4), the actual spraying pressure (approx. 0.3 - 0.5
bar) is built up which ensures the spraying of the coating material.
When using bottom cup sets, a part of this air volume will be pressed into
the cupcup via the air tube connection piece (1/28) and ensures the paint
transport to the nozzle.
It is also possible to operate these spray guns using turbines. For such an
operation, it is necessary to dismount the air converter (1/19), which
prepares the compressed air for low pressure according to the process
described above, and to replace it by corresponding blower adapters
(available upon request).
The coating material is transported via the thread connection piece for paint
(1/29) into the nozzle holder (1/7) and then reaches the nozzle (1/4), which
adds the coating material to the atomizing airflow. The AKKORD needle
(1/12) opens and closes the nozzle.
The generated coating material cloud will be encapsulated by an outside air
jacket, which is produced by the special geometry of the nozzle and of the
nozzle cap, and will then be guided to the work piece. Thus, this system is
able to considerably reduce clouds of atomized spray material from
escaping.
