Solutions to create additional dust collector capacity
With changing levels of production and modifications to existing systems becoming a solution, some of you may be asking how can I get extra capacity out of my dust collector?
Wood dust extraction system, LEV COSHH testing and LEV Thorough Examination & Test in East Sussex - South East England
Here we show you an example of how we have ahcieved this for one of our customers.
Screen solutions in East Sussex, recently asked us to review their wood dust extraction system, where they believed there had been a drop in performance. Although this wasn't identified by the previous LEV COSHH testing company.
Screen solutions had also installed a new CNC machine and the extraction did not appear to be adequate, although they had been told otherwise.
Our P601 P604 certified LEV COSHH testing engineer went to site to carry out a brief inspection of their wood dust extraction system. Having reviewed the previous LEV Thorough Examination & Test reports there did indeed appear to be a drop in overall performance, although no reason was given. It could potentially be due to a much higher resistance to flow with the new CNC machine.
Our LEV Testing Engineer carried out a number of system checks and noticed that the fan inlet pressure appeared to have risen significantly (although this had not been directly recorded in the last LEV thorough eA balancing damper to the new CNC machine was also found to be approx 50% closed although this made little difference to the overall system airflow examination & test report). Note the fan was on the product / wood dust extractor 'dirty' side.
A balancing damper to the new CNC machine was also found to be approximately 50% closed although this made little difference to the overall system airflow.
There also appeared to be some external damage to a silencer or duct fitted on fan inlet, although it was unclear the extent of the internal damage.
It was also noticed that a tight 90 degree bend was fitted to the fan inlet. This is not good LEV design practice and a significant drop (10 - 15%) in performance can occur.
A centrifugal fan should always be fitted with either 3 - 4 duct diameters of straight duct. Alternatively the LEV proposals engineer should have the capability of producing a well designed fan inlet loading chamber to provide maximum fan efficiency. Often this will take up little more room than a 1.5 - 2D 90 degree bend. Other checks were done to confirm the filter differential pressures, duct flows.
Following these initial brief checks various calculations were done to check the LEV design pressures & flows and compare against measured.
Using fan laws, improvements in air flows were calculated based on the above data. The data showed that there did indeed appear to be a partial blockage in the inlet duct (silencer) of approx 500pa. It was also deduced that a balancing damper would need to be fitted to a beam saw, in order to achieve the airflow on the CNC mc.
With these improvements and the fan inlet plenum an increase in airflow of 15 -20 % was predicted. We gave a guarantee of the performance improvement stating we would achieve the required airflow for the CNC m/c and Screen Solutions ordered the works.
Our LEV site installation engineers did find a partial collapse on the fan inlet duct with a substantial amount of product. A fan loading chamber was designed manufactured & installed by R&B Industrial together with new inlet ducting and other minor works, including fitting of airflow indicator gauges on the beam & CNC machines.
We then carried out system balancing and an LEV Thorough Examination & Test on the 17 branch LEV system. As a minimum Screen Solutions wanted the beam saw, CNC & at least one other machine to be run consecutively. We were able to achieve this & in addition a further 2 machines could be run consecutively.