Giù nelle profondità del Peak District risiede il più grande impianto di demolizione e riciclaggio delle batterie nel Regno Unito. Gestito da HJ Enthoven & Sons sul sito di una storica miniera di piombo, l'azienda ricicla su 100,000 tonnellate all'anno di batterie piombo-acido industriali e automobilistiche ed è uno degli impianti più ecologicamente responsabili ed efficienti per il riciclaggio di piombo nel mondo. Data la natura tossica delle batterie, la Società è molto consapevole delle proprie responsabilità ambientali e ha investito notevoli risorse per garantire che l'ambiente locale non sia influenzato dalle sue operazioni.
The breaking up of the batteries and the recovery processes involve crushing the complete battery and then separating out all the individual metals, plastics and chemicals. The first stage involves crushing the batteries in a high speed hammer mill, a process that breaks the components into small parts for subsequent separation. The next stage of the process sees the crushed parts passing through primary and secondary rotating filter screens to separate acid, plastic and metallic fractions. In order to optimise the overall separation process and removal of the lead sulphate sludges for recovery the internal surfaces of the screens require continuous cleaning with internal high pressure jet-washing sprays. However, the external surfaces of the screens can become blocked and regular cleaning is required. Without effective high pressure washing of the screens’ external surfaces, HJ Enthoven cannot achieved the required levels of material separation required to successfully operate the battery breaking aspect of its business.
Historically, external screen washing was performed using a single high pressure pump to feed the spray nozzles. However, the original and subsequent pumps used were not up to the demands of the breaking process and required frequent attention and maintenance, resulting in costly plant downtime. Having struggled with this situation for a number of years the Company decided in 2005 to instigate a major review of this aspect of the process in order to overcome these problems and reduce the associated costs.
It was at this time that Cat Pumps entered the scene, providing much needed information on spray nozzle performance curves. Working alongside Enthoven’s engineers, Cat Pumps brought its extensive knowledge of high pressure pumping gained on similar industrial applications to the table. “In many respects, we took on a consultancy role,” says Cat Pumps UK general manager Brian Hubbard. “Over a period of several months, we undertook an evaluation of the pumping requirements in order to provide HJ Enthoven with a number of alternative solutions that addressed the many issues that emerged from our meetings. It was time well spent as we were able to demonstrate not just the technical capabilities of our pumps to operate in an extremely challenging environment for long period, but also our engineering design resources.”
Dopo molte considerazioni, che hanno coinvolto le proposte di altri fornitori di attrezzature, HJ Enthoven ha scelto di andare con Cat Pumps poiché avevano dimostrato una chiara comprensione dell'importanza del processo di lavaggio a spruzzo sull'impianto di frantumazione e avevano mostrato dove si potevano risparmiare sui costi . È stato nel tardo 2007 che Cat Pumps ha ricevuto l'incarico di progettare un pacchetto basato su skid "pronto all'uso" composto da tre pompe a pistone triplex ad alta pressione serie 6811K, due funzioni e una in standby, complete di motori, pannello di controllo, serbatoio di testata e smorzatori di pulsazioni. Le pompe della serie 6811K sono dotate di collettori a blocco 316 SSL per resistenza e resistenza alla corrosione e pistoni in ceramica che massimizzano la durata della guarnizione. Per soddisfare l'ambiente esigente in cui operano presso HJ Enthoven, le pompe erano dotate di basamenti in ghisa e incorporavano speciali collettori di aspirazione che consentono un flusso di liquido esterno.
According to Brian Hubbard the pumps offered higher levels of energy-efficiency than experienced in the past, so HJ Enthoven would get double the flow rate for similar electricity consumption. “We provided consultancy to help design the system and establish the pump requirements, balancing effective cleaning against water and energy consumption,” reports Brian Hubbard.
“Our pump package has the effect of doubling the output flow of the existing pump, enhancing the effectiveness of the process and also vastly increasing pump reliability and eliminating down-time. The inclusion of a standby pump provides built-in redundancy so the process could continue when any one of three pumps is out of service e.g. for routine inspection and parts replacement.”
The pumps feed a single pipeline into the spray heads which wash various screens which were previously prone to blinding. Motorised valves allow the plant operators to turn these individual areas on and off as required and set sequencing cycles. Capable of providing pressures up to 4000psi and giving a flow rate of 2.6m³/hr, the pumps are required to operate 24 hours a day in a very demanding environment. The water supply comes from flooded mineshafts and does contain dissolved carbonates, which can be a problem for some pumps but not for Cat Pumps.
In any application where high pressure pumping is required and a constantly smooth flow rate needs to be achieved, the triplex positive displacement pump is arguably the most economical choice. The triplex pump employs three synchronised plungers, which give it the ability to deliver a predictable, smooth and constant flow. The smooth flow greatly reduces the possibility of system failure caused by excessive pulsation. With Cat Triplex Pumps, the synchronised plungers can produce flows of 0.1 – 265l/min. at pressures up to 690bar.
HJ Enthoven ha installato e commissionato il rig di Cat Pumps all'inizio di 2008 e dopo 12 mesi le prestazioni sono state più che all'altezza delle aspettative. "Ora stiamo eseguendo le pompe" sotto il controllo del PLC "incorporate nella sequenza di avvio e spegnimento automatico per il demolitore della batteria", commenta Paul Grainger Engineering Manager, HJ Enthoven & Sons. "Le Cat Pump hanno fornito un servizio professionale e amichevole, dalle prime fasi di progettazione fino alla messa in servizio e alla successiva manutenzione e supporto delle apparecchiature."
“Performance so far has been far better than anticipated,” he continues, “with pressure and flow satisfying our operating requirements. Overall there have not been any operational problems. We were advised by Cat Pumps in the initial stages that after 12 months continuous operation the pumps would require a routine service involving the replacement of seals and valves etc. When we inspected the pumps with Cat Pumps after more than 12 months, very little work was required, which even surprised Cat Pumps given the amount of work that they had been subjected to. We have been delighted with the performance of the equipment to date.”
Whilst the pump package meets the performance requirements in terms of pressure and flow, HJ Enthoven has been able to reduce substantially the costs incurred in pump maintenance, spare parts and downtime. In addition, the three pump set-up is far more efficient to run in terms of energy consumed.
Per maggiori informazioni contattare;
Cat Pumps (UK) Ltd, Fleet, Hants.
Tel: 01252 622031 Fax: 01252 626655