Graco Inc.

Rosengrens improves emission rates monitoring with P-Mix™ II

Proportioner P-Mix™ II was the right choice

Rosengrens in Mora, Sweden belongs to the Gunnebo group and manufactures safety boxes for documents and valuables. The finishing of the boxes is done in a durable 2K coating oxiranester. This is a modified epoxy, typical in Scandinavia, with solid contents of 67 percent. In order to improve the monitoring of emission rates, Rosengrens wanted to upgrade from a mechanical proportioner with pressure monitoring, to a high-tech electronic metering and monitoring system with on-line reporting.

The electronic proportioner P-Mix™ II was the right choice for Rosengrens. The unit meters the flow and monitors both A and B components, using the patented Graco technology with sequential dosing controlled by program in the PLC. The dosing of the components is done in volume, not in flow. This is an advantage, since the rheology of the components, such as viscosity and temperature, can vary from batch to batch. Due to frequent triggering and de-triggering of the gun, the mixing accuracy can be affected. The resulting overdoses of components would be highly visible in the end result.


Smekano, Graco’s distributor in Sweden, configured a P-Mix™ II system incorporating a colour changer with 7 colours, 3 catalysts and one common flushing agent. The controller with user interface for the configuration and setting of all parameters has been selected with an RS-485 module for networking. It is used to automatically collect production and emission data and is located in a non-IS area.

The IS fluid panel is located in the paint mix room and contains feed modules of Merkur® 40:1 ratio pumps and elevators with back-gear agitators for 200 L drums. An advantage with the stainless steel feed module is that the system can easily be converted to WB 2K system when needed. As a part of the overall concept to use P-M ix™ II and the software AMR (Advanced Material Reporting), the flushing line also has an IS flow meter to monitor the usage of solvent. An important factor why Rosengrens chose Graco was the ability to use predefined Graco software for production and emission reports.

A Gun Flush Box was installed in the spray booth to accommodate an electrostatic Pro Xs™ 4 AA gun for airassisted airless application of the paint. Not only does this allow the user to control the colour change in the most economic way, but it also collects the solvent used in the purge mode.

According to production Engineer John Sjöström at Rosengrens, the payback period for the complete installation is 2 years, with savings realised in paint and solvent use and in labour cost.

For more information contact: Ulf Bengtsson at Smekano, tel: 4642380380, fax: 4642148620