The problems encountered in closed circuit systems are like those in open systems – corrosion, suspended solids, scale, and microbiological contamination.
However, there are differences between the systems which require us to treat them in different ways. The fixed volume, low make-up of a closed system allows us to dose water treatment products at much higher levels than is possible in open systems, where water is constantly lost to drain. Much better corrosion control can therefore be achieved in closed systems. Another factor is that the dissolved oxygen level in a closed system should be low which should reduce corrosion rates. Higher biocide levels and long contact times allow good microbiological control in closed systems to be achieved. Scaling is not generally a problem unless there is substantial make-up.
B & V Chemicals has a full range of scale and corrosion inhibitors, pre-commission cleaners, system flush chemicals, and biocides for use in closed circuit heating and chilled systems. This range also contains many specialist products formulated for use in specific specialist or problematic situations.
CLOSED CIRCUIT INHIBITORS
Multi-metal inhibitors – suitable for systems containing Aluminium
|BV202||Multi-metal corrosion inhibitor||Molybdate / nitrite blend||First choice premium multi-metal corrosion inhibitor with BuildCert approval. Suitable for hard and soft water.|
|BV639||Multi-metal corrosion inhibitor||Nitrite and molybdate based formulation.||Economical in use. Excellent buffering capacity. Suitable for hard and soft water.|
|BV589||Multi-metal corrosion inhibitor||Blend of corrosion inhibitors||Extremely cost effective formulation. Suitable for hard and soft water.|
|BV1048||Multi-metal corrosion inhibitor.||Molybdate + Blend of corrosion inhibitors||BuildCert approved. Does not contain Nitrite or Boron based additives Suitable for hard and soft water.|
|BV203||Multi-metal corrosion inhibitor for soft water systems||Phosphate based||Ideally suited to soft water systems. Does not contain nitrite.|
|BV206||Multi-metal corrosion inhibitor for soft water systems||Molybdate and phosphate based||Ideally suited to soft water systems. Does not contain nitrite.|
Corrosion inhibitors unsuitable for Aluminium
|BV154||Nitrite based inhibitor 1% dose rate.||Nitrite and borate||An effective corrosion inhibitor for systems containing steel and 'yellow metal' components.|
|BV267||Nitrite based inhibitor 1% dose rate. with indicator||Nitrite and borate||Excellent corrosion control for steel, cast iron, copper and brass. Contains Phenolphthalein as an indicator.|
|BV205||Nitrite based inhibitor 0.5% dose rate.||Nitrite and borate||Economical concentrated formulation. Excellent corrosion control for steel, cast iron, copper and brass|
|BV889||High conc. product.||Nitrite and molybdate based||Concentrated formulation. Excellent corrosion control for steel, cast iron, brass and copper|
|BV653||High conc. product.||Blend of corrosion inhibitors||Concentrated formulation. Dose 0.1% to chilled systems and 0.2% to LPHW systems. An effective corrosion inhibitor for systems containing steel and 'yellow metal' components|
|BV550||Biostable formulation.||Molybdate and borate||Excellent corrosion control for steel, copper and brass. Contains a low level of nutrients (no phosphate or nitrite), thus the product does not encourage microbiological growth,|
Our range includes tannin based closed circuit inhibitors and inhibitors specifically formulated for optimal use in MPHW and District heating systems. Please contact our technical department so that we can help you to pin point the most effective product for use in your system.
CLOSED CIRCUIT BIOCIDES
The main problematic micro-organisms found in closed circuit systems are bacteria, which can lead to the rapid build-up of biofilms in pipework and on heat exchanger surfaces causing reduction in efficiency, flow restrictions and under deposit corrosion.
It is much easier and more cost effective to maintain microbiological control within a closed-circuit system than to clean up a heavy build-up of biofilm.
|BV585||For biocidal flushing and system protection. Can be dosed with high pH inhibitors||Proprietary||Low toxicity. Very stable biocide for use with high pH nitrite based inhibitors. Excellent against Pseudomonas ssp. Optimal biocidal activity after 24 – 48 hrs contact. Effective over a pH range pH 8.0 to 11.0. Stable up to 80°C. Test kit available.|
|BV1532||For flushing and system protection. Suitable for the protection of neutral pH systems.||ITA blend||Does not contain copper stabiliser. Effective over a pH range of 6.5 to 8.5. Stable up to 50°C.|
|BV595||For flushing and system protection. Suitable for the protection of neutral pH systems.||ITA/BNP blend||Very effective against NRB’s Effective over a pH range of 6.5 to 8.5. Stable up to 50°C.|
|BV105||Suitable for the protection of neutral pH systems.||BNP||A broad-spectrum bactericide. Low toxicity. Effective over a pH range of 6.0 to 8.0. Stable up to 40°C.|
|BV1507||For flushing and system protection. Suitable for the protection of neutral pH systems.||Glutaraldehyde||Has a broad spectrum of activity against bacteria and their spores, fungi, also effective against sulphite reducing bacteria (SRB) Effective over a pH range pH 6.5 to 9.0. Stable up to 60°C. Rapid biocidal action.|
|BV254||For flushing and system protection. Suitable for the protection of neutral and alkaline pH systems.||THPS||A broad-spectrum product, very effective against SRB’s. Effective over a broad pH Range 3 -10. Stable up to 60°C.|
|BV1528||For flushing and system protection. Suitable for the protection of neutral pH systems.||Proprietary||A highly effective non-oxidising biocide containing a synergistic combination of biocides. Ideal for use in closed circuit systems. Effective against, Pseudomonas spp and Sulphate-reducing bacteria. Effective over a pH range of 6.5 to 8.5. Stable up to 50°C.|
To prevent the recirculating water in chilled systems freezing as outside temperatures get below 0oC in the winter it is often necessary to add antifreeze. It is also important to note that when closed circuits contain 25% glycol or above, the glycol has a biostatic effect i.e. preventing the growth of bacteria. As the concentration falls below 25% glycol can act as a food source for bacteria. As bacteria consume the glycol they produce acidic bi-products lowering the pH of the system and accelerating corrosion.
|BV70||General purpose antifreeze||Mono ethylene glycol||25% Monoethylene Glycol will reduce the freezing point of water down to -11 to -12°C.|
|BV69||General purpose inhibited antifreeze||Mono ethylene glycol molybdate based multi-metal inhibitor||Contains a low toxicity corrosion inhibitor formulation + mono ethylene glycol. Dose at 25% system volume to obtain optimal freeze protection and corrosion control.|
|BV134||Food grade antifreeze||Mono propylene glycol||Low toxicity product. 25% Monopropylene Glycol will reduce the freezing point of water down to -11 to -12°C.|
|BV133||Food grade antifreeze + inhibitor||Mono propylene glycol + ‘food safe’ inhibitor||Contains a low toxicity corrosion inhibitor formulation + mono propylene glycol. Dose at 25% system volume to obtain optimal freeze protection and corrosion control.|
Specialist Closed Circuit Products
|BV891||High conc. Neutral product.||Nitrite based||Neutral nitrite additive designed to be added to multi-metal systems where the nitrite component of the inhibitor has been degraded by microbial action.|
|BV491||pH adjuster and buffer supplement used to decrease the pH in closed circuits where Aluminium is present.||A combination of acidic components and buffer||Specialist additive for lowering the pH of alkaline solutions to below pH 8.0 in order to ensure optimal corrosion protection of aluminium.|
|BV5||Closed Circuit Antifoam||Mineral oil based antifoam||Used to control foaming in closed systems. Very concentrated formulation|
|BV139||On-line Descaler||A blend of polymers and sequesterants||Removes the scale responsible for 'kettling' and poor heat transfer. Restores heat transfer efficiency. No system shut down required|
|BV201||Azole Supplement Suitable for use in open recirculating cooling systems, evaporative condensers and closed water systems.||An aqueous solution of azoles.||Neutral pH formulation. Systems that have a very large surface area of copper may need additional copper corrosion inhibitor. Can be used as a supplementary treatment to protect copper and brass.|
|BV916||Concentrated azole Supplement Suitable for use in closed water systems.||An aqueous solution of azoles.||A very high strength solution of benzotriazole. Systems that have a very large surface area of copper may need additional copper corrosion inhibitor.Neutral formulation so addition of this azole supplement will not affect system pH.|
|BV167||Biofilm Dispersant Applications include oil removal in cooling towers and biofilm removal in closed systems.||Contains a low foaming surfactant.||Compatible with anionic and cationic species. Use in conjunction with an appropriate biocide. Biofilm removed from pipework surfaces will be removed so the system must be assessed prior to use to ensure that dislodged biofilm can be removed from the system efficiently.|
Pre-Commission cleaning and system flush chemicals
The pre-commission cleaning of hot water heating and chilled systems has become more important over recent years due to the equipment used being more susceptible to blockages at strainers, control valves and small bore heat exchangers. System contaminants such as mill-scale, jointing compounds and fabricating debris need to be removed by chemical cleaning and high velocity flushing, which will then allow the on-going water treatment regime to work effectively in preventing corrosion and microbiological fouling. Older systems that have accumulated deposits due to lack of the correct water treatment can be cleaned by a similar method.
Our range of specialist, effective pre-commission cleaning, biocidal flushing and system flushing chemical formulations are outlined below:
|BV398||Pre-commission & system flush||An aqueous blend of chelants, dispersants and wetting agents.||Versatile formulation. Suitable for systems of all ages. Excellent removal of corrosion deposits. Very effective pre-commission cleaner and system flush formulation.|
|BV850||Pre-commission cleaner||A concentrated solution of phosphonate, polymers, chelant and wetting agent.||Heavy duty concentrated pre-commission cleaner. Removes oil, grease and flux residues, disperses light iron oxide deposits|
|BV141||Very low toxicity biodegradeable pre-commission cleaner||An aqueous solution of surfactants, polymers and organic oxygen scavenger.||Low toxicity formulation, formulated as a pre-commission cleaner for use on sites where there are restrictive discharge limits|
|BV140||Pre-commission cleaner||Blend of cleaning and dispersing agents||Effectively removes oil, grease and flux residues, disperses light iron oxide deposits. Contains nitrite to passivate bare metal surfaces|
|BV155||System flush and specialist corrosion remover||An aqueous solution of phosphonates, citric acid, polymers and organic oxygen scavenger.||For use in old systems with hard corrosion deposits. Can be left in the system for several weeks. Will remove tightly adhered corrosion debris.Solubilises and disperses iron oxide particles.Passivates cleaned metal surfaces.|
|BV143||System flush||A blend of cleaning and dispersing agents.||Blend of cleaning and dispersing agents, lifts and disperses inorganic and organic debris from pipework surfaces.|
|BV1455||On-line cleaner for closed circuit systems||A blend of cleaning and dispersing agents with an effective biodispersant.||As this product lifts and mobilises system contaminants including biofilm it should only be used in conjunction with in-line or side stream filtration. Cleans and passivates bare metal surfaces, preventing under deposit corrosion and prolonging system life. Compatible with our full range of closed circuit water treatment LPHW and Chiller formulations.|
A summary of our core range of products is included above. Many other formulations for closed circuits are also available
Our Technical department is always available for advice on product selection, problem solving and compatibility with other formulations already in use in particular systems.
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HuwaSan specialise in the production and distribution of chemicals for water treatment. B & V Chemicals are water treatment supply partners in the UK.