Pump Group Extend Life of Power Station Pipework Using Belzona 1812 Ceramic Carbide

Pump Group were contacted to assist with an issue at a Coal Fired Power Station where the site engineers had sections of pipework which were failing within an unreasonably short period of time. The pipes are situated in part of the FGD (Flue Gas Desulphurisation) Plant part of the power station, which operates to remove harmful chemicals from the exhaust gases from the power station, specifically Sulphur Dioxide (SO2). The gasses are passed through a limestone slurry which ‘scrubs’ the SO2 from the gasses emitted. A direct product of this process is that Calcium Sulphate (CaSO3) and CO2 are created. The limestone slurry, now containing Calcium Sulphate is then pumped away for further treatment. This slurry is highly abrasive (due to the limestone) and very corrosive (due to the Calcium Sulphate), which means it wears away at pumps & pipework very quickly – the average lifetime of the pipes had been less than 6 months before pipes would need to be replaced with a new one. Pump Group engineers recommended coating with Belzona 1812 – Ceramic Carbide to provide a pipe interior which would outlast the poor performing existing pipes. To reduce the application time & to increase accuracy, Pump Group fabricators manufactured a flanged mould with a machined insert. This mould is then bolted onto the pipe prior to coating, and allows the technician to completely fill all spaces with Belzona 1812 uniformly whilst ensuring the internal dimensions are to specification. The wetted areas were shot blasted to remove all possible contaminants and also to achieve a surface profile of SA2.5 @ 75microns which is required for the Belzona to bond successfully to the substrate material. The pipes were then salt tested to confirm acceptable levels of nitrates and other contaminants which can jeopardise the longevity of the coating. The internal surfaces of the pipes were coated using Belzona 1812 Ceramic Carbide around the .  Belzona 1812 was selected as it is a composite material combining extremely hard closely packed abrasion resistant ceramic aggregates in a polymeric binder ideal for the repair and protection of substrates being damaged by particle abrasion. Following Belzona 1812 being applied on the pipes, the pipe flange faces were then final machined true using a diamond tipped tool. Pump Group had already carried out similar Belzona applications for the same client on the FGD plant and the client had seen a 50% increase in … Continue reading

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Belzona Repair of a Lined Acid Receiver – Chemical Industry

The Acid Receiver was removed from a chemical production site installation following customer concerns regarding the flange integrity and the receiver was transported  to Pump Group for repair. The tank has a metal shell lined with polypropylene and then wrapped with glass fibre.  Upon inspecting the tank, it became clear that both the PN16 Plastic flanges had been heavily corroded and were no longer safe to use in their current state. It appeared that acid had slowly leaked past the gaskets on both the flanges, and the acid had corroded through the glass fibre, the polypropylene and even the metal shell. Pump Group engineers proposed a course of action to remove the damaged flanges and rebuild new flanges using Belzona 1111 Super Metal.  Belzona 1111 was selected because it is a metal repair composite which has excellent adhesion to metals and plastics, meaning it can be used to both re-form the flanges and bond the flanges to the tank. The damaged flanges were cut off and the edges prepared by removing the glass fibre and polypropylene 2” back from the existing flanges and then grit blasting the necessary areas. A mild steel forming plate was manufactured and bushes welded on which had the same PCD and clearance hole size as the existing flanges. 2 split rings were manufactured our of 316 Stainless Steel which were located behind the flange faces. The flanges were then rebuilt with Belzona 1111 using the forming plate and split rings to ensure the correct size. Belzona 1111 was used to bond the rebuilt flanges to the tank, and the mould and split rings were released once the Belzona had cured. The OD of the Nozzles and flanges were coated with Belzona 1321 Ceramic Super Metal. Belzona 1321 is designed to provide corrosion resistance to surfaces – it has high chemical resistance which will prevent acid attack causing damage to the flanges should  leakage occur in the future. For more information on how we can utilise our extensive Belzona knowledge and Coating Facilites to assist your company with your operational needs, please contact a member of our Repairs Team on +44 (0)161 864 4678 or via email repairs@pumpgroup.co.uk.    

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Profile Recovery of Impeller using Weld & Belzona 1812 Ceramic Carbide

Our customer was experiencing issues with corrosion & erosion destroying their pump units on a Flue Gas Desulphurisation (FGD) application. Whilst purchasing the uprated impellers – made out of a more resistant Super Duplex, even then the impellers were lasting less than a year before the pumps needed removing from service for overhaul. The impeller was despatched to Pump Group with the aim of sourcing a more long term and cost effective solution rather than just replacing the impellers with new from the OEM.  Pump Group suggested rebuilding the impeller using specific Belzona Polymeric Coatings designed to withstand such damaging conditions. The impeller was bead blasted and jet washed clean, and metal inserts were fabricated to roughly rebuild the impeller profile. The inserts were then welded in to position and hard face welding carried out over the edges to increase the strength. The impeller was shot blasted to remove all possible contaminants and also to achieve a surface profile of SA2.5 @ 75microns which is required for the Belzona to bond correctly to the substrate material. The unit was then salt tested prior to coating to confirm the lack of presence of nitrates and other contaminants which can jeopardise the longevity of the coating. The surface was rebuilt using Belzona 1812 Ceramic Carbide.  Belzona 1812 was selected as it is a composite material combining extremely hard closely packed abrasion resistant ceramic aggregates in a polymeric binder ideal for the repair and protection of substrates being damaged by particle abrasion. Once the Belzona was applied (6mm thick) the impeller diameter and neck was machined with a diamond tipped tool to achieve required clearances within the pump. A mandrel was manufactured to allow the rotating element to be dynamically balanced to G2.5 at 1000 rpm. By utilising Belzona, the impeller was rebuilt in a much shorter period of time, approximately half the cost of a new impeller, and the Belzona 1812 Ceramic Carbide coated impellers achieves twice the life of the OEM impellers. For more information on how we can utilise our extensive Belzona knowledge and Coating Facilities to assist your company with your operational needs, please contact a member of our Repairs Team on +44 (0)161 864 4678 or via email repairs@pumpgroup.co.uk.  

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6.5 Tonne Split Case Pump Repair for Chemical Plant

Industry – Chemical Production Two 6.5 tonne Mather & Platt 28” / 22” Split case pumps were removed from site as part of planned maintenance, to carry out a complete overhaul. All bearing, shaft diameters and housings were checked and found to be within tolerance for their respective class of fit. The white metal bearings were re-lined for re-use. Further out from the journal diameters there were deep marks due to action from the seals and baffle plates.  We undercut the markings and rebuilt with Belzona 1131 Bearing Grade® polymer and machined to OEM specifications. Damage from Off-Axis running was present in both DE & NDE Bronze bearing shells. This was remedied by white metal lining the shells then boring to original dimensions. The top & bottom halves of the volutes were generally in good condition, but with internal surface scaling present.  The internals were grit blasted to surface profile specification SA2.5 and 2 coats of Belzona 1341 Supermetalglide® were applied. Belzona 1341 Supermetalglide® was selected as it improves pump efficiency by using hydrophobic technology to repel process fluids and reduce turbulent flow, lowering energy costs. The units underwent seal conversions top AES Split Cartridge Seals with Silicone Carbide running faces and LabTecta® Push-Fit bearing protectors. The Stainless Steel impeller was in good condition with only superficial markings. The impeller was dynamically balanced at 1000rpm to G2.5 prior to reassembly. After assembly, the split case pump was hydrostatically tested to 1.5 times working pressure and was placed in our Performance Test Cell, laser aligned to one of our slave motors and performance tested. The units underwent detailed vibration analysis using Pruftechnik VibExpert system and a performance test report was produced and issued to the customer. The units had been made redundant several years earlier, and had been sat dormant since then. Plant cooling water requirements changed and Pump Group were able to refurbish and modernise the pumps within the clients’ budget.  The unit was returned to site within the allowed time frame to meet customer requirements. For more information on how we can utilise our extensive workshop and testing facilities to assist your company with your operational needs, please contact a member of our Repairs Team on   +44 (0)161 864 4678 or via repairs@pumpgroup.co.uk.

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Nuclear Power Main Cooling Water Valves Get The BELZONA® Treatment

Industry – UK Nuclear Power Generation A nuclear power station producing 1000 MW requires in the region of 150,000 m3 of cooling water per hour when active. The flow is regulated by the Main Cooling Water (MCW) Valves, which throttle the supply. As a result of this duty, the valves can be damaged by the effects of the constant water flow & cavitation. The client had removed 4 of these 66” MCW valves and sent them to Pump Group for refurbishment. The butterfly valves had previously been coated by others, and it was clear to see that there was extensive damage to the valve. Pump Group had previously used Belzona® 2141 Anti-Cavitation polymer to coat the pipes immediately downstream of the valve; as the client was happy with the performance of the Belzona they elected to use it on the valves. On arrival the valves were disassembled and inspected fully. The pressure side of the valve was worn but in reasonable condition, however the downstream side had suffered major cavitation damage. The existing coating had worn away completely near the leading edge, allowing substantial damage to occur to the metal due to the Corrosion – Erosion cycle. The existing coating was fully removed in our workshop then the base metal was hot chemical washed prior to being grit blasted. Once the surface profile was grit blasted to surface preparation specification SA 2.5 (75 micron surface profile), the metal was then tested to ensure salts and nitrates present were less than 3ppm concentration. This is to ensure that the Belzona polymer bonds correctly to the substrate correctly. Belzona® 1111 Super Metal was used to rebuild the severely worn areas to the original profile. On the upstream side, 4 x 250 micron coats of Belzona® 1321 Super Metal were applied. This side of the valve doesn’t have to be protected from cavitation, so a coating was selected to increase efficiency, whilst still offering long lasting protection against erosion/corrosion from the sea water. Another advantage of 1321 is that it has very high compressive strength, making it ideal for use on the upstream side of the valve. On the non-pressure side, 3 x 1000 micron coats of Belzona® 2141 ACR-Fluid Elastomer coating were used. The high elasticity of this polymer is perfect for combatting cavitation; nullifying the damaging effects from the shockwaves created by the collapsing bubbles. In addition to the Belzona coatings, … Continue reading

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Pump Group Use Belzona to Repair 12m Screw Feeder

Pump Supply & Repair Group arranged transport of the 12m Screw Feeder from an EON Power Station Site. The unit was taken out of service because of extensive wear to flights & central tube. Non Destructive Testing was carried out on the flights, the shaft and the teeth. Ultra sonic testing determined the thickness of the worn 304 Stainless Steel Lining, and MPI Testing (Magnetic Particle Inspection) was used to identify cracks in the surface. In total, 326 faults were detected that required welding along the face of the screw, and in several areas the steel lining had worn down to less than 3mm thickness. The cracks were welded using hard face SS2333 rods to prevent future cracking. The teeth were substantially worn and several teeth were missing. All the teeth were removed and new teeth were welded on with 304 SS rods. The teeth were hard face welded on 2 sides using MAC Hard E306 rods to further increase their abrasive resistance.   The 10 ton screw was then grit blasted to SA 2.5 @ 75 microns to ensure correct surface profile for Belzona application.  Belzona 1812 Ceramic Carbide was applied to 15mm on the wear pads on the flights to build up to original thickness. Belzona 1812 was then applied at a thickness of 4mm to the shaft and all working faces of the screw & flights. The total job turnaround of the screw was 10 weeks from the go-ahead to completion. For more information on how Pump Supply & Repair Group can utilise our Belzona facilities and expertise, please contact our Operations Director, Martin Cooper on 0161 864 4678 or via email at mcooper@pumpgroup.co.uk

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Belzona Protects Trench From Acid Attack

The customer was experiencing problems within a 40 metre long trench near a tanker off-loading area. Tankers carrying both Sulphuric and Nitric acid were being emptied regularly, with small amounts of acid being spilled each time. This acid had corroded through large areas of the concrete floor and trench, and there was a danger of the acid corroding through the remaining concrete and contaminating the underlying soil & water table. One of our specialist engineers attended site to survey the problem, and concluded that the extremely hard wearing yet versatile range of Belzona Polymeric Coatings would be ideal for this scenario.  The ability to apply the Belzona polymer coatings cold and the fast curing properties were ideal for this situation. Once given the instruction to proceed by the customer and all of the relevant Risk Assessments and Method Statements had been approved, a team of our factory trained Belzona approved technicians attended site to carry out the repair. They cleaned the concrete using high pressure steam cleaners, removing all traces of acids and oils to ensure the Belzona product bonded to the concrete substrate. First the technicians used Belzona 4141 Magma Build, a concrete specific repair polymer, to rebuild the concrete back to the original profile, then applied 2 coats of 4311 Magma CR1, which is a high performance coating designed to withstand the most aggressive chemical attacks. The Belzona process took our 2 engineers 8 days from start to finish, which is a lesser period than how long it would have taken to concrete the damaged areas, which would have also needed 28 days to cure. The 4311 Magma CR1 has many times the chemical resistance of concrete, meaning that the Belzona repair will far outlast any traditional repairs that could have been used. For more information on how Pump Supply & Repair Group can utilise Belzona Coatings both in our workshop and on-site, please contact our Site Services Manager, Charles Lambley, on 07887 721900, or email him on clambley@pumpgroup.co.uk

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Authorised Coating Centre

We are pleased to announce we have recently been appointed the U.K.’s first Belzona Authorised Coating Centre

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