Closed Circuit Chemicals | B & V Chemicals

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.

In January 2024, we introduced an innovative range of polyamine inhibitors specifically designed for closed circuit systems. These polyamine inhibitors offer an all-in-one solution that delivers improved heat transfer, exceptional corrosion protection, and a highly cost-effective treatment option.

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 pinpoint the most effective product for use in your system.

CLOSED CIRCUIT INHIBITORS

Multi-metal inhibitors – suitable for systems containing Aluminium

Product code	Application	Composition	Benefit
BV206	Multi-metal corrosion inhibitor for soft water systems	Molybdate and phosphate based	Ideally suited to soft water systems. Does not contain nitrite.
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.
BV1520	Multi-metal corrosion inhibitor	Nitrite and molybdate based formulation.	Economical in use. Excellent buffering capacity. Suitable for hard and soft water.
BV1721	Multi-metal corrosion inhibitor	Molybdate / Nitrite	First choice multi-metal inhibitor providing fast passivation, enhanced scale inhibition and improved pH buffering capacity.
BV982	Multi-metal corrosion inhibitor	Molybdate, Borate, and Silicate	Suitable for Multi-Metal systems including those with Aluminium.

Corrosion inhibitors unsuitable for Aluminium

Product code	Application	Composition	Benefit
BV205	Nitrite based inhibitor 0.5% dose rate.	Nitrite and borate	Economical concentrated formulation. Excellent corrosion control for steel, cast iron, copper and brass
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,
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
BV889	High conc. product.	Nitrite and molybdate based	Concentrated formulation. Excellent corrosion control for steel, cast iron, brass and copper
BV1710	Nitrite inhibitor with indicator	Nitrite based blend	Economical concentrated formulation. Excellent corrosion control for steel cast iron, copper, and brass with phenolphthalein indicator.

POLYAMINE INHIBITORS FOR CLOSED CIRCUITS

For more detailed information on our polyamine inhibitors for closed circuit systems, please visit this page. Additionally, we've published several blogs on this topic that you may find helpful:

Product code	Application	Composition	Benefit
BV1725	Closed circuit systems, heating and chilled. Suitable for aluminium.	Blend of Polyamines	Blend of amines for corrosion and scale inhibition in closed circuit systems. Suitable for heating and chiller systems. Provides corrosion protection for steel, cast iron, copper, brass and aluminium. Helps prevent scale deposition. Dose 0.8-1.2L/m3.
BV1723	Closed circuit systems, heating and chilled. Not suitable for aluminium.	Blend of Polyamines	Blend of amines for corrosion and scale inhibition in closed circuit systems. Suitable for heating and chiller systems. Provides corrosion protection for steel, cast iron, copper, and brass. Not suitable for aluminium. Helps prevent scale deposition. Dose 0.8-1L/m3.
BV1722	Older closed circuit systems where a progressive clean is required prior to preventative treatment.	Blend of Polyamines	Blend of amines for corrosion and scale inhibition in closed circuit systems. Recommended for use in older systems where a progressive clean is required prior to continuous dosing with preventative treatment. Contains a high level of iron chelators, as well as dispersants to mobilise existing iron deposits. Suitable for heating and chilled systems. Provides corrosion protection for steel, cast iron, copper, brass and aluminium. Helps prevent scale deposition. Dose 3-5L/m3.

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.

Product code	Application	Composition	Benefit
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.
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.
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.
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.
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.
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.
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.

Anti-Freeze

To prevent the recirculating water in chilled systems freezing as outside temperatures get below 0^oC 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.

Product code	Application	Composition	Benefit
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.
BV70	General purpose antifreeze	Mono ethylene glycol	25% Monoethylene Glycol will reduce the freezing point of water down to -11 to -12°C.
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.

PRE-COMMISSION CLEANING AND FLUSHING

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:

Product code	Application	Composition	Benefit
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
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
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.
BV590	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
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.

SPECIALIST CLOSED CIRCUIT PRODUCTS

Product code	Application	Composition	Benefit
BV5	Closed Circuit Antifoam	Mineral oil based antifoam	Used to control foaming in closed systems. Very concentrated formulation
BV1049	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
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.
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.
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.
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.
BV455	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.

A summary of our core range of products is included above. Many other formulations for closed circuits are also available

Contact our Technical team https://www.bvwater.co.uk/contact-us for advice on product selection, problem-solving and compatibility with other formulations already in use in particular systems.

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