Compared to pumps, mixers often seem to be the poor relation – with some thinking that any mixer will do. Paul Davies, Key Account Manager at Landia, reports on how one company has benefitted from making a careful choice.
No matter how careful you are, working at height, especially outdoors in winter or in strong winds, is not brilliant. For the maintenance team at Glatfelter, a leading global supplier of engineered materials, this, following regular failures of a mixing system for an open-topped tank, meant it was time for an upgrade.
Hayes GFS, who are experts in the installation and refurbishment of glass-fused-to-steel tanks, suggested that Glatfelter try an externally-mounted mixer from Landia.
Manufacturers of quality key products for industries such as food & beverage, electrical, building and medical, Glatfelter’s open-topped 1000m. above-ground (7m) glass-lined steel tank (used for pH correction) was fitted with an internal propeller mixer that for repair and servicing was only accessible via vertical ladders, and then use of a cumbersome mechanical winch – although the problems were manyfold.
Failures with the mixer had become all too frequent, so on top of the arduous and very awkward process of having to retrieve it, there was also the downtime of having to wait for it to be repaired, and sometimes replaced altogether with a brand-new unit. This had become a costly, ongoing exercise that was no longer viable.
A new mixing system would have to be much easier to manage, and also be able to deliver on performance in a very aggressive application with pH levels from three, right up to 13. The old internal mixer also couldn’t prevent crust building up in the centre of the tank – and when the vessel was drained down, Glatfelter discovered that the mixer had been scouring the bottom of the unit. The reinforcing bars could be seen, which wasn’t good at all, so it was time for a replacement tank.
Having the mixer on the outside of the tank is always going to provide benefits, but to be perfectly honest, Glatfelter were a little sceptical about how any mixer could deal with the range of different fibres used in their manufacturing process, where the dewatering rate can vary significantly. The old internal mixer couldn’t stop some fibres from settling in the middle of the tank, which with significant effluent volumes being handled, led to a small mountain building up in the centre.
The mixer became completely blocked and the crust was so thick it wouldn’t disperse, so several times over the years, Glatfelter had to drain everything down and pay for contractors with cranes to come in and dig it all out.
Four years on, we are proud to say that the installation of our 11kW Jet Mix system is described as a “resounding success”; so much so that Glatfelter decided to invest in three more Landia mixers. Two further JetMix systems now serve a 1500m. vessel, with another JetMix installed in a 500m. unit. Both containers work as balancing tanks before the wastewater goes on to other treatment processes at the Gloucestershire plant, including two DAF systems.
For each tank, the pump outlets are horizontal, allowing mixing to continue, even if tank levels are low. JetMix, which is mounted through the side of the tank wall, makes it well-suited for mixing liquids with a high viscosity, such as drained or digested sludge. The optimal motor cooling function also makes it an ideal choice for liquids with high temperatures.
All of the health and safety issues caused by the old mixing system have been removed, including working in confined spaces. And even though there are very high pH levels, the first Landia mixer is still in very good condition four years on from its installation. And despite all the variables in the wastewater, the mixers, which run almost 24/7, have received excellent performance reports, with our in-house service team now visiting the Glatfelter facility every six months to carry out preventative maintenance.
t: 01948 661 200 | pd@landia.co.uk | www.landia.co.uk