Coating technology saves 30% on pump energy costs

Polymer composites can create a sacrificial and renewable working surface that protects the structural integrity of an original substrate. Pumps are typical examples of plant whose life can be extended and high performance assured by efficient predictive maintenance and repair. Castings, impellers and volutes wear due to corrosion, erosion, cavitation and mechanical damage and all can be effectively rectified with polymer composites. A major UK automotive manufacturer provides an excellent illustration of what can be achieved. To demonstrate potential gains industrial services provider Eriks suggested evaluating the efficiency of one of the company's pumps that handles process water in the Henkel, metalwork pre-treatment process prior to body coating. This 22kW ELPO pump was put to test at ERIKS' Electro-Mechanical Services (EMS) workshop in Southampton and it was found to be under-performing by a minimum of 30% against the manufacturer's original test data. Compared to the manufacturers original test data this pump was under performing by at least 30%. The unit was then dismantled and all components examined for wear. The pump was heavily corroded and the pump impeller worn, burred and imbalanced. The mechanical seal had seized and the pump was out of alignment with the motor. The volute was cut-water worn, the bearings showed evidence of fretting and corrosion and the motor was not inverter rated. Repair process All components that required coating with Loctite polymer composites were first steam cleaned to remove any residue and salts and then bead blasted to achieve a surface roughness of 75 microns. Loctite 7515 was used to pre-treat the substrates to prevent corrosion and improve adhesion between the metal parts and the polymer composites. Next, Loctite 7117 was applied as a hold coat to smooth the surface imperfections and provide a key for the thicker layers required to return the pump to its original dimensions. A build coat of Loctite 7226 was used to replace many years of wear and create a tough surface, resistant to future wear. In common with others in the range, this compound offers distinct advantages over traditional repair methods such as hard metal welding or flame spraying, both of which are difficult and costly to apply to large surfaces. In contrast the Loctite 7226 is easily applied on all surface sizes and offers the extra benefit of corrosion protection. Also, it does not create any heat stress during its application. Loctite 7226 is one in a family of protective coatings and compounds used by ERIKS. This can be applied by trowel as it is a non-sag epoxy that was chosen for its ability to protect against fine particle abrasion. The range provides a choice of grades for fine particles through to coarse and also specific products for pure chemical attack, corrosion protection and high impact. Temperature resistance across the range typically extends from -30°C up to 120°C but there are also special grades that can be used up to 230°C. Overall, the products provide good protection against fresh and sea water, ammonium sulphate and sodium hydroxide. Following the application of Loctite 7226 another coat of Loctite 7117 was applied to achieve a very smooth finish to reduce friction within the pump and improve its energy efficiency. The pump was then fitted with new bearings and both oil and mechanical seals. The impeller was dynamically balanced, the pump re-assembled and a new 22kW high efficiency motor fitted. Motor and pump were then fitted to the bedplate and laser aligned. Efficiency led savings A second performance test was then carried and the results were described as outstanding. The remedial work had restored the pump to original specification, increasing its efficiency by 30%. The cost of the repair amounted to £5,542. But offsetting this, in the first year alone, was an estimated energy reduction of £3,936. This was calculated at £0.08/kWh at 12 hours per day with an 80% load. The Enhanced Capital Allowance Scheme, a Government incentive for investment in energy saving equipment, also enabled the automotive manufacturer to reclaim £585.90. So, with all the savings taken into account the cost of the pump repair was just £685. But of course substantial savings will continue to be made that will far outweigh this reduced sum. On carbon emission, the figure is 28 tonnes, on energy savings it's 51.90 MWh and over a five year period this accrues to a five-year energy saving amounting to £19,680. And that is on one pump alone. Needless to say the manufacturer is now evaluating the potential energy savings that could result from more pumps receiving the Loctite treatment from Eriks.