Extract to atmposhere
Fumes are removed from the laser system at a very high rate. The source of airflow is an industrial type fan capable of providing enough pressure to withstand the restrictions of the system and deliver a rate of airflow that is somewhat over specified. The fan moves contaminated air from the laser along rigid duct, usually 150mm diameter at minimum. The laser is connected to the rigid duct by way of a short length of industrial grade flexible hose, typically 100mm diameter. Close to the laser should be some form of gate or throttle to fine-tune the rate of flow. The contaminated air is expelled at roof height, usually assisted by a jet cap where the contaminants dissipate and become harmless.
The fan is almost always located outside of the building and usually it is floor mounted but it can also be roof or wall mounted.
The advantages of this system:
- No workspace is lost because the majority of the system is outside of the workspace.
- This method offers by far the highest rate of air flow allowing for maximum extraction performance at the laser machine. This is good for the health and safety of the operator but also it is a major advantage for cutting applications where an increased rate of extraction can significantly increase the quality of the cut.
- As the restrictions within the system never change the performance is consistent, even over a very long period of time and no matter what the application.
- The high-performance of this type of system can be used for devices such as vacuum tables, etc, as well as performing the main task of fume removal.
- Absolutely no consumable items are incorporated within this system meaning very low running costs.
- The fan is maintenance free and the system enjoys almost zero servicing costs.
- There is the potential to operate more than one laser system from a single extraction source.
- The fan will, on average, last many years longer than a turbine without servicing.
- There can be no accidental inadequate operation that might expose the user to potentially harmful fumes and the system does not require any monitoring during operation.
- A replacement fan can be sourced very fast from multiple supply sources.
The disadvantages of this system:
- A high-power electrical source is required, typically three-phase.
- On start-up the draw on the electrical supply can be rather high. After start-up the fan should be very efficient. For this reason it is normal to minimise the number of times that the fan is started/stopped during the day.
- The installation is static: i.e. the equipment cannot be moved after installation.
- Installing such a system is time consuming, involves several different professionals and can involve changes in the structure of walls and roofs.
- Installation costs can be high if the run of duct is particularly long or the fan is located anywhere other than on the floor
- Operation of the fan is very noisy; typically 85db. This can be reduce by using one or more attenuators and further by approximately 20db by using an acoustic box but these things add significant cost.
- If very high odour materials are processed (like rubber) then smells can be noticeable outside.
- The installation can look rather "ugly".