Page 12 - HUB-4 Magazine Issue 83

Tyrone 3-day Open Event
Fintan, added, “Everything from this tank is pumped up to the 150tph two-grade cyclone sand plant to separate the silt, the clays, the organics, and plastics from the sand.
“This tank also has a system to remove any floating polystyrene and plastics that have not been pumped out of the tank; so, it is a self-cleaning system that will remove all that material and pump it back onto the trash screen maintaining its cleanliness and blocking it from entry into the system.
“On this plant we double-wash the sand so there are two stages of removing all the silt, plastics, and organics so that we end up with two very clean sands – the fine sand is a 0-2 and the coarse sand is a 2-5, both are despatched to stockpile via powered radial conveyors. Additionally, we have incorporated a blending system on the sand plant to blend as much of the fine sand into the coarse sand depending on what grading we are trying to achieve.”
We then followed the process to where the silts, the clays and the -5mm organics and plastics that come out of the top of the cyclones are fed down onto a large vibrating trash screen situated on the top of the T – Clear 800 thickener, this screen removes all the trash and organics prior to the water treatment; effectively removing it before it gets into the system. By keeping it out of the system it prevents the spray nozzles being blocked and prevents the build-up of material in the clarifier water tank.
The thickener has a large rake which spans the full diameter of the tank. They rotate slowly around the bottom of the tank ploughing all the settled silt into the central cone section of the thickener from where there is a pump that sucks all the thick sludge out. The system measures the load on the rakes, so the sludge is only discharged when it is at the correct density. Additionally, there is a facility to raise and lower the rake system which will prevent blockages in the future should anything unexpected occur.
A self-cleaning system:
Additionally, another area where the very fine trash material is being removed is the rotating surface scraper on top of the thickener tank. Should any trash material less than 1mm or fibrous trash material get past the vibrating trash screen it will be removed from the thickener by a surface scraper and then through a longitudinal discharge point where it is pumped from back onto the trash screen, enabling the system to constantly clean itself. This system ensures that no trash enters the clarified water storage tank.
Central Control Room:
The whole plant is operated from a central control room allowing the operator a full view of the plant. Within this control room is a mimic screen for the wash plant and the water treatment plant so the operator can see all the critical information for the plant such as pressures, flow rates, the amps being used and the levels in the tanks – all from one central location.
There is also a multi-screen camera system so he can visibly see all the critical components of the plant. Additionally, a further screen showing belt speed, tph, time of plant start, if the plant stopped and weight on the belts.
Our tour continued into the press room...
The Fraccaroli & Balzan over beam filter press:
The Fraccaroli & Balzan overhead beam filter press [partners with Tyrone] installed at Hartshill Quarry offers so much more than other presses in the marketplace.
The Fraccaroli & Balzan overhead beam filter press is one of the largest over beam press installed in the UK Aggregate Industry! The whole operation from start to finish takes 60-90 minutes to complete the cycle depending on the feed material with 10 minutes to clear the plates, which is extremely fast for such a large press. The moisture content of the filter cake can easily be controlled from the HMI screen by adjusting one parameter.
Fintan gave us the facts, “The thick sludge is transferred from the thickener tank into the sludge tank which holds 550 cubic metres of sludge which is a very large sludge tank. The reason that it is so large is to ensure that there is sufficient storage enabling the filter press to operate all night pressing all the sludge out so maximum utilisation can be achieved. With the filter press running day and night, this allows the operator to set the washing process up again in the morning.
“What make this filter press stand out is that there are so few moving parts!”
Fintan continued,” At the end of the press cycle the four hydraulic rams move out and the large sliding header plate retracts. When that retracts a robot above the press moves forward and two pistons come out and pull 10 plates back; it then travels forward to the next pack, two go out and then it pulls ten back again, travelling up the press very quickly pulling sets of ten out.
“The robot mounted on top of the press has two other functions – it can shake the filter plates to assist the discharging of the filter cakes and it also washes the plates. Many other filter presses do not have the ability to shake the plates.
Because this press is so large the sludge is fed in at both ends which reduces the filling time and equalises the pressure throughout ensuring the cake has the same dryness all the way through.
Fintan added, “The filtrate water [clean water] is discharged through the corner ports of the filter plate which is all collected at the end of the filter press exiting down one pipe which incorporates a turbidity meter which will inform the operator that if the water is not clean there is a damaged filter cloth which the operator needs to change. A flow meter also measures the flow of clean water coming out of the press which when the flow is reduced to a set point it instructs the system to shut the pump off and to open the press to discharge. So, if the set point is reduced a drier cake can be produced; or increased for a cake with a higher moisture content.
Design and ease of maintenance:
The key thing about this press is that the overhead beams sit to the side which allows full access to everything on the top; unlike traditional overhead beams where everything sits in the middle and include a chain drive mechanism and hooks on the chains to open the plates.
On the F&B press, maintenance is super easy as everything sits to the side and there is full access round all sides of the press.
It also operates an automatic washing system which washes from the top down. This is completely different as alternate systems wash from the bottom up. When it is washing the press, a mobile trolley moves along with the washing system and collects all the water which is returned to the thickener.
It’s an extremely fast automated system, we have full remote access to all the control on the plant so if there are any alarms, operator problems or issues we can remotely dial into the plant and can access all the alarms and the history and can then offer advice to the plant operator as to what he needs to action.
The whole design philosophy of this new plant is making everything as easy as possible, easy to access, easy to maintain, easy to service which has been a total success.
John Edwards – Editor, HUB-4, commented, “Having viewed dozens of wash plants over the last 20 years to describe this plant as ‘state-of-the-art’ is an understatement. The attention to detail is quite frankly superb! All the HUB-4 team would like to congratulate Tyrone on this stunning installation and thank them for the tour and hospitality.”
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www.hub-4.com Nov/Dec- Issue 83