The Pultrex fume extraction system is based around an open topped enclosed infeed system with ancillary fume extraction at the die exit.
Many pultrusion operations utilise a fume extraction hood mounted over the top of the infeed/resin tank and die.Whilst this tends to reduce the overall styrene levels in the workshop it is extremely uncomfortable for an operator leaning over the infeed as the fumes are lifted from the tank straight into his face whilst any process problems are attended to.
Styrene fumes being heaver than air are far easier contained using a floor mounted system.
The Pultrex system is configured around the standard Pultrex infeed system framework. Conventionally this would be an open framework with resin tank, resin return tray and fibre guidance system mounted from the support frame. When fitted the Fume extraction system comprises:
- Frame work panelling
- Large diameter extraction tube with radial fan
- Secondary extraction tube with die extraction vent and adjustable extraction arm
Taking these elements in order:
The sides of the infeed framework are fitted with removable panels for cleaning within the resin tank and fibre guidance area. The panels are interlocked to the machine control circuit to prevent the machine operating unless the panels are in place.
The fibre infeed end of the framework, below the fibre carding frame is fitted with a fixed panel which supports the radial extract fan which has facilities for connection to the customers extract ducting outside the framework. The extract fan has a flange inside the infeed frame work for attachment to the main extraction tube.
The out feed end (die end) of the infeed framework is also fitted with a fixed panel which supports the other end of the main extraction tube. This panel also supports one end of the larger secondary fixed extraction tube.
Large diameter extraction tube with radial fan:
Running horizontally along the central position of the infeed framework from the fibre infeed end (carding plate end) to the die end is a large diameter spiral wrapped tube. One end of the tube is attached to the radial extract fan mounted in the infeed end panel. On the bottom surface of this horizontal tube there are a series of holes cut into the tube to act as extraction vents. The holes are in the bottom of the tube to prevent the ingress of resin should it be accidentally spilt on to the tube through resin spillage.
The other end of the extraction tube is supported within a larger diameter spiral wrapped tube which is fitted within the Hot die bed section. The extraction tube can be quickly disconnected from the radial fan and slid inside the die bed tube for ease of cleaning within the infeed area.
Secondary extraction tube with die extraction vent and adjustable extraction arm
A large diameter spiral wrapped tube is mounted within the machine hot die bed. This acts as a support and guide for the main extraction tube when it is stowed away for cleaning.
A smaller diameter tube is fitted to this and terminates in an extraction grill within the top of the die bed at the profile exit end of the die. This removes the fumes/smoke coming from the exit end of the die
In addition a smaller diameter pipe exits the machine bed on one side and is angled through 90 degrees to terminate in a flange at the side of the die bed. Attached to this flange is a flexible extraction hood arm that can be positioned over the die exit.
This system has proved to be very effective in maintaining low styrene levels within a pultrusion workshop. The system to a certain extent is self regulating. When there is a small resin tank and drip tray within the infeed area and emissions are low the air flows in the area are low. When a large resin tank and tray are fitted in the infeed area then the resultant free space around the tank is small and the airflow around the tank and tray increases.