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Vapour degreasing – A guide for production engineers
Vapour degreasing – A guide for production engineers
This guide for production engineers explains why vapour degreasing is the most effective and economical process for cleaning of manufactured components. The start of a new year is always a good time to review your existing cleaning process and ask yourself ‘am I using a safe modern solvent for vapour degreasing?’.
Vapour degreasing is the simplest but most effective degreasing and cleaning process which, until recently, has been subject to little change since it was first invented in the early part of the last century. This is a very mature chemical technology which legislation is now effecting changes so fundamental that the more accurate name for the process “Condensation Cleaning” should be used to reflect the improvements in equipment design, chemistry, reduced emissions, economies in usage of solvents and the subsequent environmental acceptability compared to the open topped tanks so ubiquitous in factories and workshops worldwide. The alternatives in equipment design offer differences in technology, which guarantee the continuing use of this process in the future, need to be considered and understood.
The cleaning tank in the corner of most engineering shops hides a very well researched process using sophisticated chemistry. Its popularity is in its simplicity. The tank sump is heated, fitted with cold coils around the internal surfaces at the top to retain the vapour. Fill to a few centimetres with a non-flammable solvent able to dissolve contaminants, boil to form a vapour 3 to 4 times heavier than air to fill the tank. Hot solvent vapour condenses on the cooler target parts at workplace temperature. The hot liquid solvent dissolves oil and grease and other contaminants. Used solvent returned to the sump revaporises continuing the cycle until parts have achieved the same temperature as the vapour when, with no further condensation, the process is complete. Simple but perfect. Highly productive and economical, parts removed from the cleaning process are clean, warm, and dry in 5 to 10 minutes.
Historically chlorinated hydrocarbons have been the solvents of choice for the “Condensation Cleaning” process. Compatible with most materials of manufacture, stable in constant use, producing a non-flammable saturated vapour heavier than air at a temperature greater than ambient. In Europe, the United States and in other advanced industrialised economies increasingly stringent legislation to control emissions of VOCs, especially solvents, has led to new formulations for paints and other coatings where water replaces most of the solvent. In the early days the quality of water-based paints was not as good as traditional solvent-based coatings, but innovation has driven the development of new polymers with results as good as, if not better than, the solvent-based originals.
As with coatings, cleaning systems have had to change. With increasingly demanding standards of cleaning required for precision engineering, electronics, optics etc solvents are often first choice, for reasons outlined above, but these have been targeted by regulators and alternatives are encouraged by the relevant authorities and law makers often without serious consideration of unintended consequences. For example, water-based cleaning is encouraged as the obvious alternative, but this has many disadvantages compared to condensation cleaning as although the machines are simple and relatively cheap the processes require multiple heated tanks for immersion or spray processing or long programmed cycles in batch machines for cleaning, rinsing, and drying. Water based processes are slow, energy intensive and occupy more floor space than solvent-based condensation cleaning equivalents where only one tank with a small footprint is needed, delivering shorter process times and, most importantly for the environment, using minimal energy.
The ideal cleaning process would be “Condensation Cleaning” using water but due to the physical characteristics of the water vapour/steam and the inability to carry onto the surface of the targeted parts surfactants to remove the oil, grease and soils and the difficulty and expense of rinsing and especially drying this can only ever be a dream.
Historically chlorinated hydrocarbons have been the solvents of choice for the “Condensation Cleaning” process. Compatible with most materials of manufacture, stable in constant use, producing a non-flammable saturated vapour three to four heavier than air at a temperature greater than ambient. The traditional solvents such as trichloroethylene exhibits all these characteristics however concerns about its carcinogenic properties and the danger to operators by exposure, led to a continuing search for a safer alternative. 1,1,1 trichloroethane based solvent formulations became popular in the mid part of the last century as a safer replacement. An excellent solvent, safer for users, it proved to be depleting the protective ozone layer around the Earth and was subsequently banned. With the development of the REACH legislation in Europe, trichloroethylene was again allowed with restrictions and stringent controls for use in authorised machines which control emissions to very low figures close to zero.
High performance vapour degreasing and cleaning
EnviroTech Europe have been supplying vapour degreasing solvent formulations for 40 years constantly responding to increasingly stringent regulatory requirements for environmental and safety laws and the need for improved cleaning standards. ProSolv® 5408e is a new sustainable solvent blend with near zero OPD (Ozone Depletion Potential) and GWP (Global Warming Potential) for high performance degreasing and cleaning which ticks all the boxes with the perfect profile for a vapour degreasing solvent. Soft on the environment and safer for users with high performance, improved cleaning, and lower costs. Lower boiling point, economical with energy with low solvent losses, faster production, reduced costs, easy handling. Exceptionally low surface tension to penetrate micron sized holes and close contact surfaces. Sustainable and secure for future use as your ‘forever solvent’.
Sealed Tanks
As with all legislation for chemical use regulation and restrictions drive development of associated processes and equipment. Sealed tanks are now standard with many different designs available. The most common are discussed below.
The single tank hermetically sealed machines favoured by some manufacturers uses a process tank to contain the solvent and a separate storage tank/vapour generator. Baskets loaded with parts to be cleaned are introduced from the top or through access points on the side of the tank. Lids or doors hermetically seal the tank. Solvent is pumped into the process tank where agitation, ultrasonics or pumped liquid is circulated through the parts. Used Solvent is removed to the vapour generator, condensing coils controlling the vapour are linked to coils located in the vapour zone which, when the cycle is complete, collapse the vapour. The process tank is emptied. Controlled air introduced to process tank is then recycled through carbon absorption units to remove traces of solvent until the concentration is within regulatory standards when the lid is released for the basket of parts, clean and dry, to be removed and replaced with a further basket. Variations of process within the hermetically sealed tank are possible using sprays of cold or hot condensed solvent, immersion with or without ultrasonics and revolving baskets to cover most of the problems experienced when processing machined and fabricated parts. Continuous external distillation of the contents of the vapour generator is also an option depending on contamination.
The alternative technology is much simpler and uses well tried techniques not requiring the long recovery times of the hermetically vacuum sealed processes. The multilevel system uses a standard vapour degreasing tank design with a sealed loading section above the process tank. Components to be cleaned loaded in work baskets or jigs are fed to the load section by hand or conveyor, an internal platform raises and lowers the baskets in controlled cycles.
Loading complete – the load enclosure is sealed to completely isolate the process. Then seal on the process tank is opened and the basket automatically lowered into the cleaning section which can be simple condensation cleaning or immersion cleaning with or without ultrasonics or power sprays. Revolving baskets can also be added to improve cleaning in blind or through holes or oil ways in castings and fabrications.
On completion the basket rises to the area where the condensation coils are located, and parts allowed to drain and dry, basket raises into the load section when the process tank is sealed. A fan circulates air within the load area which can be recycled through carbon absorption systems if no external exhaust is preferred.
As baskets entering the loading space contain parts drained and dried only very small amounts of solvent are carried in the exhausted air which is monitored to ensure compliance with appropriate legislation. When this is complete the seal opens fully for removal of cleaned components. The loading section can be fitted with top or side seals allowing baskets to flow through on conveyor systems or be removed by hand or hoist. No solvent enters the work area. Both processes will produce parts cleaned to the highest standards but the choice of which offers the best solution needs a little more consideration.
The hermetically sealed vacuum process is complicated with the need to move liquids in the machine. It is relatively slow as the carbon adsorption process has to remove high levels of solvent from the recirculated airstream from the process tank. This is inefficient as adsorption rates for carbon fall rapidly with increasing saturation. Final levels of solvent in the tank when the lid or loading door opens will be dragged into the workshop and the area where the operator is working. Long process cycles reduce throughput.
The simpler multilevel systems where movement of liquids is not required are more efficient and offer much faster process times. Cost of manufacture is also reduced as no liquid movement or vacuum is involved. The extracted loading section ensures no leakage of solvent into the work area giving complete safety for operators and factory staff. Envirotech Europe also offers workplace air monitoring to ensure VOC’s from the solvent are within exposure limits and your machine is operating to specification.
Conclusions
Both designs of process machines discussed above fully comply with the emission regulations of the EU and U.S authorities. Which to choose will depend on many factors which should be discussed with equipment and solvent suppliers who have the experience to advise on which offers the best process for the application. Equipment and solvent must work together, so it is advisable to ensure that the suppliers co-operate to offer a package with high levels of responsible care and product stewardship to ensure the best and safest installation. EnviroTech personnel and distributors are trained to work with equipment suppliers to advise on the use of ProSolv® 5408e vapour degreasing solvent for the most satisfactory outcome.
The “Condensation cleaning” process still gives the highest levels of economical cleaning with minimum energy usage, low footprint on the factory floor, safety for the operator, and high production rates with low solvent usage and environmental impact. With the new generation of sealed cleaning machines its future as the process of choice is assured.
Photograph of Solvac equipment courtesy of C&C Hydrosonics.
FURTHER INFORMATION
Please visit our website https://www.envirotech-europe.com/prosolv5408e for information about other uses and applications for ProSolv 5408e.
Visit www.envirotech-europe.com/applications-and-case-studies for information about uses and applications for all EnviroTech Europe products.
For more advice, please telephone us on +44 (0) 20 8281 6370 or use our website contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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Related Posts
Video: ProSolv 5408e – Vapour degreasing cycle using hermetically sealed equipment
Vapour degreasing cycle using hermetically sealed equipment.
ProSolv 5408e is a high- performance solvent cleaner used for sustainable and future proof vapour degreasing. Soft on the environment and safe for users, it offers improved cleaning at lower costs. Low boiling point, economical with energy with low solvent losses, faster production.
Innovation driven by legislation
Vapour degreasing, with or with-out ultrasonics, is the oldest, simplest and most effective solvent degreasing and metal cleaning process used today. It has, until recently, been subject to little change since it was first invented in the early part of the last century. In the UK, Europe, United States and other advanced industrialized economies increasingly stringent legislation to control emissions of VOCs, Solvents with a high Global Warming Potential (GWP), or a high Ozone Depletion Potential (ODP), and those compounds associated with human health concerns has led to Envirotech Europe manufacturing new formulations for precision cleaning solvents with low or near zero potential.
Halogenated hydrocarbons are the solvents of choice for vapour degreasing and cleaning. The process is essentially simple. A tank with a sump to contain the solvent, heaters at the base and condensation coils around the top section to control the height of the vapour is all that is needed. When heated in the sump halogenated solvents produce, in most cases, a saturated vapour between 3 and 4 times heavier than air at a temperature greater than the ambient temperature of the parts to be cleaned. This allows the solvent vapour to condense on the surface of the parts. The condensate dissolves the contaminants such as oil, greases, flux, and soils returning the used solvent into the sump of the machine for recycling into vapour which continuously condenses onto the parts until they have achieved vapour temperature when, with no further condensation, the process is complete. Parts removed from the cleaning machines are very clean, warm and dry.
The most common halogenated solvents, in use for commercial purposes, are non-flammable so present no risk in this process. Perchloroethylene, used mainly for dry cleaning, methylene chloride previously used widely in paint strippers, 1,1,1- trichloroethane and trichloroethylene used for vapour degreasing were the original materials used based on chlorine chemistry. However continuing concern about the environmental impact and danger to operators by exposure to chlorine-based solvents, especially trichloroethylene, has led to a continuing search for safer alternatives, such as ProSolv 5408e , a trans-1,2-Dichloroethylene based solvent mixture that is non-flammable.
The ProSolv 5408e vapour degreasing process gives the highest levels of economical cleaning with minimum energy usage, low footprint on the factory floor, safety for the operator, and high production rates with low solvent usage or environmental impact. With the new generation of sealed cleaning machines its future as the process of choice is assured.
A more detailed version of this article can be viewed here:
https://www.vapour-degreasing.com/solvent-degreasing-and-metal-cleaning/
Animation of Solvac hermetically sealed equipment by kind permission of CC Hydrosonics Ltd. https://www.cchydrosonics.com/
FURTHER INFORMATION
For more advice, please telephone us on +44 (0) 20 8281 6370 or use our website contact form. All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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The best in vapour degreasing, corrosion protection, metal cleaning and surface treatment
EnviroTech Europe are specialists in metal, plastic and other substrate cleaning, pretreatment and protection.
We offer a range of approved products tailored to your industry, which are cost effective, energy efficient, safe for operators and the environment.
Our products are used in the following industries:
- Electronics and Electrical
- Environmental
- General Cleaning
- Industrial and Manufacturing
- Marine and Maritime
- Mechanical Engineering
- Medical Device Manufacturing
- Military
- Motorsport
- Power Generation
- Railways and Automotive
PRODUCTS:
EnSolv CC-A Vapour Degreasing Solvents For Precision Metal Cleaning:
A family of environmentally friendly precision vapour degreasing and cleaning solvents for the aerospace, precision engineering, medical, optical and electronic industries.
ProSolv 5408e Environmentally Sustainable High Performance Vapour Degreasing Solvent:
Zero ODP (ozone depletion) and GWP (global warming potential) – Sustainable and secure for the future.
SuperCORR A Advanced lubricant and corrosion protection compound:
Specialist barrier film corrosion protection products, based on synthetic materials to provide safe, effective, environmentally friendly solutions to lubrication and corrosion problems.
Aquus CL-One General Purpose Industrial Cleaning Agent:
A non-toxic, water based surfactant system which exhibits a combination of characteristics not found in any comparable commercially available system.
Clarea Industrial Degreasing Solvents:
Non chlorinated, industrial wipe, brush, dip and immersion cleaning solvents for removing dirt, oil, grease and other contaminants without causing harm or leaving residue.
VOC Exposure Monitoring:
We have portable test equipment that logs the Volatile Organic Compound (VOC’s) content in the air from various strategic positions around your degreasing equipment, including the operator position
FURTHER INFORMATION
For more advice, please telephone us on +44 (0) 20 8281 6370 or use our website contact form. All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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Latest News
New study disputes TLV for nPB
A detailed comprehensive review of 1-bromopropane studies confirm current recommendations by EnviroTech for occupational exposure levels for safe usage of EnSolv® as a vapour degreasing solvent.
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| view/ download this document in Adobe Acrobat Format |
Update on a safe occupational exposure level for 1-Bromopropane
Prepared for EnviroTech Europe, Ltd.
Prepared by Dr. Mark Stelljes
SLR International Corporation
September 2014
Executive Summary
This paper re-evaluates EnviroTech Europe’s (ETE’s) current occupational exposure level recommendation of 100 ppm for 1-bromopropane (1-BP) [106-94-5] in the vapor degreasing industry in light of the recent lowering of the ACGIH Toxicity Threshold Value (TLV) from 10 ppm to 0.1 ppm. The 0.1 ppm value is based on a study of 86 workers exposed to 1-BP during its manufacturing in China in four different facilities. The authors reported significant effects at all 1-BP exposure levels down to 1.28 ppm. The 1-BP in these facilities had concentrations of the isomer 2-bromopropane [75-26-3] (2-BP) present as a contaminant at about 10-20 times the level sold for vapor degreasing.
There are several factors that undermine the conclusions reached in the paper that a concentration of 1.28 ppm resulted in toxicity in exposed workers. These factors were related to:
(1) Exposure measurements – passive rather than active samplers were used, and concentrations varied by more than tenfold for the same activity.
(2) Exposure via other routes in addition to inhalation – described worker activities indicate substantial dermal exposure, which increases the overall dose of the chemical relative to just inhalation exposure.
(3) Exposure to other chemicals – at least 20% of the workers were previously exposed to 2-bromopropane
(2-BP), and no testing was done for other chemical exposure.
(4) Statistical methods and interpretations – instead of using paired patient-exposure data, authors categorized exposure into groups (e.g., high, low); this resulted in apparent statistical relationships that may not be biologically relevant.
(5) Lack of robust dose-response relationships – when evaluating typical doseresponse relationships, only a single parameter (vibration sense in the toes, a subjective parameter) was shown to be significantly different across all dose levels.
(6) The outcome of the subjective vibration sense test was in part dependent on the testing doctor – this dependency should remove the test and its results from consideration in the paper as a scientifically defensible endpoint.
When all of this information is considered as a whole, it is unlikely that the 1.28 ppm lowest effect concentration reported in the paper is accurate. The interpretations in the Li et al. study are inconsistent with expectations based on the ways in which 1-BP acts in rodents relative to humans. Studies on how 1-BP acts in the body of rats and mice and studies on metabolism of the chemical in humans indicate that humans should be no
more sensitive to 1-BP than either of these rodents.
Based on the weight of evidence available for the toxicity of 1-BP in humans and rodents, there is no credible scientific reason to target an occupational concentration as low as 10 ppm or 0.1 ppm. ETE’s current recommendation of 100 ppm should be maintained, and employers together with vapor degreasing personnel should not be concerned about the much lower levels recommended by the ACGIH.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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ACGIH Threshold For N-Propyl Bromide Solvents
What You Should Know About The ACGIH’s Threshold For nPB Solvents
If you work with industrial chemicals, materials or solvents then you may have heard of the American Conference of Governmental Industrial Hygienists (ACGIH). The ACGIH is a scientific, but non-governmental body of industrial hygienists that publishes Threshold Limit Value (TLV) opinions on chemicals such as n-propyl bromide the base solvent for EnSolv formulations. These TLV opinions are not held to the same standards as limits set by an organization such as OSHA in the USA, but are still published in books available on the ACGIH website. You or someone else in your company might be familiar with these TLVs.
In March 2014, the ACGIH published a new TLV for n-propyl bromide (1-bromopropane). This TLV was set at 0.1ppm, and refers to “commercial grade bromopropane (99% 1-BP with 0.1%-0.2% 2-bromopropane).” 2-bromopropane is also known as isopropyl bromide (iPB). Modern nPB manufacturing processes result in nPB with <0.01% iPB contamination, which is of a pharmaceutical quality.
The 1-BP (nPB) properties referenced by the ACGIH rely to some degree on information first published in 1999 and 2000, which contains information that is out of date and inaccurate when referring to today’s purity of 1-BP. Some of the things to keep in mind regarding ACGIH TLV opinions include:
- TLVs are not determined by speaking openly with scientific experts, but in closed-
- Door meetings.
- There is no scientific consensus backing up ACGIH’s findings.
- ACGIH TLV opinions may involve conflicts of interest and uncertain science.
- The ACGIH is a not-for-profit organization that funds its activities by selling books; it is not a government-sanctioned panel of experts.
The IBSA et al. v. ACGIH lawsuit documents a number of these concerns involving the ACGIH and how they determine their TLV opinions. There is nothing worse than misinformation in our field – not only are safer chemicals such as nPB made to seem dangerous, but chemicals that are unsafe or unsuitable might be seen as acceptable alternatives.
It is of great concern to that in spite of the very demanding regulations already in effect in Europe some manufacturers of very expensive “new” fluorocarbon alternatives to the less expensive conventional solvents choose to imply that recent ACGIH recommendation for a reduction of exposure limits will have legal effect in Europe. This wrong and no credence should be given by users to any “recommendations” except those issued by government regulators.
The EU will establish DNEL (Derived No Effect Level) recommendations under the REACH legislation in due course and until these are issued all properly designed and maintained equipment is perfectly safe for use for vapour degreasing and any suggestion to the contrary may cause unnecessary confusion and restrict the use of this very useful technology.
EnviroTech Europe urges you and others in your company not to rely solely on TLVs, but rather on official and informed sources instead (See US EPA SNAP Approval for 1-BP). For more information on the properties of nPB and related solvents, please visit www.vapour-degreasing.com.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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Condensation cleaning, the future for solvent degreasing
Innovation driven by legislation
Vapour degreasing is the simplest but most effective degreasing and cleaning process. It has, until recently, been subject to little change since it was first invented in the early part of the last century. The name for the process is a misnomer as the cleaning is actually achieved by solvent vapour condensing on the cooler target parts and the hot liquid solvent dissolving oil and removing dirt.
Vapour degreasing is a mature technology on which legislation is now effecting changes so fundamental that the more accurate name for the process “Condensation Cleaning” should be used to reflect the way in which it works. More importantly the alternatives in equipment design and fundamental differences in the technologies which guarantee its continuing use in the future need to be considered and understood.
In Europe the United States and in other advanced industrialised economies increasingly stringent legislation to control emissions of VOCs and especially solvents has led to new formulations for paints and other coatings where water replaces most of the solvent. In the early days of these changes the quality of the coatings was not as good as solvent based coatings but innovation has driven the development of new polymers and the results are now as good as, if not better than, the solvent based originals.
As with coatings, cleaning systems have had to change. With increased legislation concerning the regulation of health and environmental safety uses of solvent have been targeted and alternatives are encouraged by the relevant authorities and law makers often without serious consideration of unintended consequences.
For example water based cleaning is the obvious alternative but this has many disadvantages compared to condensation cleaning as although the machines are simple and relatively cheap the processes require multiple tanks for immersion or spray processing or long programmed cycles in batch machines for cleaning, rinsing and drying. Water based processes are slow, energy intensive and occupy more floor space than condensation cleaning equivalent where only one tank with small footprint is needed delivering shorter process times and most importantly using minimal energy.
The ideal cleaning process would be Condensation cleaning with water but due to the physical characteristics of the vapour/steam and the inability to carry onto the surface of the targeted parts surfactants to remove the oil, grease and soils and the difficulty of rinsing and especially drying this will only ever be a dream.
Halogenated hydrocarbons are the solvents of choice for Condensation cleaning. The process is essentially simple. A tank with a sump to contain the solvent, heaters at the base and condensation coils around the top section to control the height of the vapour is all that is needed. When heated in the sump halogenated solvents produce, in most cases, a saturated vapour between 3 and 4 times heavier than air at a temperature greater than the ambient temperature of the parts to be cleaned. This allows the solvent vapour to condense on the surface. The condensate dissolves the contaminants such as oil, greases and soils returning the used solvent into the sump of the machine for recycling into vapour which continuously condenses onto the parts until they have achieved vapour temperature when, with no further condensation, the process is complete. Parts removed from the cleaning machines are very clean, warm and dry.
The most common halogenated solvents, in use for commercial purposes, are non-flammable so present no risk in this process. Perchloroethylene, used mainly for dry cleaning, methylene chloride used widely in paint strippers and trichloroethylene used for vapour degreasing were the original materials used based on chlorine chemistry. However continuing concern about the environmental impact and danger to operators by exposure to chlorine based solvents, especially trichloroethylene, has led to a continuing search for safer alternatives.
Genklene from ICI and Chlorothene from Dow Chemicals, both of which were based on another chlorinated solvent 1.1.1. trichloroethane, were to become ubiquitous in the mid part of the last century as a much safer, non carcinogenic replacement for trichloroethylene. An excellent solvent safe for users but which, with increased awareness of the environmental impact of solvents, proved to be depleting the protective ozone layer around the Earth was subsequently banned. Trichloroethylene was then allowed to be used again as a substitute for trichloroethane but with increased restrictions on its use, even though safer materials were already available. With the development of the REACH legislation in Europe, which now classifies trichloroethylene as a human carcinogen, usage will be even more difficult but will probably be authorised in machines which control factory emissions to very low figures close to zero.
Meanwhile n-propyl bromide (nPB) based cleaning solvents such as EnSolv were developed in the United States as a drop in replacement for the ubiquitous 1.1.1.trichloroethane. nPB has an identical profile, stable, non-flammable, with the same physical characteristics such as boiling point and specific gravity and it is an excellent cleaning solvent but without the potential for ozone depletion.
During this time new halogenated blends using trans1.2 dichloroethylene, a highly flammable solvent with similar chemistry to trichloroethylene were also developed for condensation cleaning. The trans 1.2 dichloroethylene is blended with a variety of different fluorocarbon liquids which are not suitable as cleaning solvents, as they have very low solvency, but are used in these blends as a fire retardants. An extremely expensive answer to a simple problem, already solved by the development of machines able to safely use the cheaper solvents.
As with all legislation for chemical use regulation and restrictions drive development of associated processes and equipment. The most important developments in affordable machines to use solvents for condensation cleaning use two different approaches and raise difficult questions as to which is the best most economical and simplest in use.
The single tank hermetically sealed machines favoured by mainly German manufacturers uses a process tank to contain the solvent and a separate storage tank/vapour generator. Baskets with parts to be cleaned are loaded from the top and lowered into the process tank. A lid then closes over the tank and is hermetically sealed. Solvent is pumped into the process tank. Baskets are immersed in the solvent where agitation, ultrasonics or pumped liquid is circulated through the parts.
When the immersion process is complete solvent is pumped to the storage tank and vapour fed to the process tank from a vapour generator for rinsing and drying. Condensing coils/panels controlling the vapour height are linked to coils located within the vapour zone which, when the cycle is complete, collapse the vapour. The process tank is emptied. The saturated air/solvent from the process tank is then recycled through carbon absorption units to remove traces of solvent from the air until the concentration is below 2 grams per cubic metre when the lid opens automatically for the basket of parts, clean and dry, to be removed and replaced with a further basket.
Variations within the hermetically sealed tank are possible using sprays of cold or hot condensed solvent, immersion with or without ultrasonics and revolving baskets to cover most of the problems experienced when processing machined and fabricated parts. Continuous external distillation of the contents of the vapour generator is also an option depending on contamination
The alternative technology is much simpler and cheaper using well tried techniques not requiring the long recovery times of the one tank processes. This is favoured by U.K. based manufacturers. The multilevel system shown in the diagram uses a standard vapour degreasing tank design with a sealed loading section above the process tank.
Work baskets are fed to the load section from a hoist or conveyor. The loading door is then pneumatically sealed to hermetically isolate the process. The sealing lid on the process tank is opened and the basket lowered into the cleaning tank which can be simple condensation cleaning with vapour generator below or an offset generator can be used with the lower section being filled with clean solvent for immersion cleaning with or without ultrasonics or power sprays. Revolving baskets can also be added to improve cleaning in blind or through holes or oil ways in castings and fabrications.
When the process is complete the basket rises to the freeboard area where the condensation coils are located and parts allowed to drain and dry. The tank seal opens to allow the basket into the load section while the lid closes again across the process tank. A fan is then activated which produces a negative vacuum in the load area. The loading door is then partially opened to allow a flow of air through the loading section which is exhausted to atmosphere or can be recycled through carbon absorption systems if no external exhaust is preferred. As baskets entering the loading space contain parts drained and dried only very small amounts of solvent are carried in the exhausted air which is monitored to ensure compliance with local legislation. When this is achieved the door opens fully for removal of basket. The loading section can be fitted with top or side sealed doors allowing baskets to flow through on conveyor systems or be loaded from hoists. No solvent enters the work area.
Both processes will produce parts cleaned to the highest standards but the choice of which offers the best solution needs a little more consideration.
The single tank process is complicated with the need to move liquids in the machine. It is relatively slow as the carbon adsorption process needs to remove high levels of solvent from the recirculated airstream from the process tank. This is inefficient as adsorption rates for carbon fall rapidly with increasing saturation. Final levels of solvent in the tank when the lid opens will be dragged into the workshop and the area in which the operator is working. Long process cycles reduce throughput.
The simpler multilevel systems where movement of liquids is not required are more efficient and offer much faster process times. Cost of manufacture is also cheaper as no liquid movement is involved. The extracted loading section ensures no leakage of solvent into the work area which offers complete safety for operators and factory staff. The disadvantage of the multilevel machine is the height of the equipment compared to the single tank machine. This will often require the equipment be installed in a pit for easy access.
Both designs of process machines fully comply with the emission regulations of the EU and U.S authorities. Which to choose will depend on many factors which should be discussed with both the equipment and solvent suppliers who have the experience to advise on which offers the best process for the application. Equipment and solvent must work together and it is advisable to ensure that the suppliers work closely together to offer a package with high levels of responsible care and product stewardship to ensure the best and safest installation.
The Condensation cleaning process still gives the highest levels of economical cleaning with minimum energy usage, low footprint on the factory floor, safety for the operator, and high production rates with low solvent usage or environmental impact. With the new generation of sealed cleaning machines its future as the process of choice is assured.
Syd Treacher is a consultant for industrial cleaning processes
Drawing by kind permission of CC Hydrosonics Ltd www.cchydrosonics.com
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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Samuel Banners Ltd appointed EnSolv distributors for UK
CONTENT ON THIS PAGE IS RETAINED FOR INFORMATION ONLY
DUE TO n-Propyl bromide now being included in Annex 14 of REACH
EnviroTech Europe Ltd (ETE) continue to publish it as historical information and to record changes occurring in legislation which have affected decisions on formulations and equipment used in vapour degreasing - the most effective, quickest, flexible and cheapest cleaning system used in industry.
EnSolv® invented and patented by EnviroTech has been a market leader all over the world for vapour degreasing. It is based on n-bromopropane (nPB) which now cannot be used as a vapour degreaser within the UK or EU without authorisation.
Archived information about EnSolv® can be found using the Discontinued Products & Resources navigation menu on this page.
Using experience accumulated over 40 years supplying and supporting users of the vapour degreasing process ETE specialists have developed “drop in” alternatives:
ProSolv®, ProSolv5408e® and EnSolv CC-A® give the same or improved level of performance and economy as the original EnSolv® products.
Please contact our advisers who are available to discuss your needs and propose the best replacement product.
Or please click here to return to our vapour degreasing products homepage for information about our current products.
EnSolv is the only realistic safe, economical alternative to the carcinogen trichloroethylene for vapour degreasing.
Responding to the increasingly stringent legislation on solvent usage EnviroTech have over the years reacted to the changes and introduced and developed the solvent minimisation programme which gives help and guidance to users in ways to reduce the amount of solvents used in vapour degreasing to comply with the EU Solvents Emission directive. This is achieved by a combination of working with partners to improve equipment, better solvent handling and more efficient use of the vapour degreasing process. Training staff in proper loading of work baskets, correct timing procedures and many more detailed improvements which when combined not just reduce solvent usage but make it safer for the operator and the environment while considerably reducing costs for users. After discussion with many potential distributors to find a partner with the same ethical standards, passion for customer service and training and with the high level of knowledge to service and support our customers we are very pleased to announce Samuel Banner Ltd will be the distributors for EnSolv in the UK from November 2013.
Established 150 years ago Samuel BANNERS Ltd were granted the patent for White Spirit and from that time they have continued to be involved with solvents manufacturing and distribution. Their extensive storage and distribution depots will offer a fast and efficient delivery for EnSolv throughout the U.K. The respected technical sales team at BANNERS are active in precision engineering, aerospace, medical, electronics and optical industries where critical cleaning is required and have an in-depth knowledge of vapour degreasing to give advice and support to all EnSolv customers. EnviroTech Europe Ltd and Banner Chemicals are both committed to Responsible Care and will continue to advise on legislative or other changes and research for our products to meet the highest quality standards.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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A Real Fire Suppression System Problem and Your Electronics and Computer Systems
HFC-227ea is replacing Halon 1301 as the gaseous fire suppression agent for data processing and electronic equipment.
However when activated in a fire situation HFC-227ea will decompose to produce Hydrogen Fluoride. This is a real and ongoing concern. Why? Because Hydrogen Fluoride causes major corrosion problems for electronics and connectors. You may save your equipment but for how long?
In 2004 the Institute of Research and Construction in Canada published a study on HFC-227ea (C3F7H) paper, Thermal decomposition products from fire suppression with HFC-227ea in an electronic facility 1. That study was followed by Corrosion of Electronic Components by Hydrogen Fluoride (HF)2 in 2008 by the Fire Research Program of the National Research Council of Canada. Both studies were published in the Journal of Fire Protection Engineering. These two in depth studies address and prove the very definite concern of Hydrogen Fluoride (HF) corrosion after a gaseous HFC-227ea fire suppression system is used in computer and other electronic environments.
The first published study by the National Research Council of Canada (NRC) in 2004 showed that HFC-227ea, a gaseous fire suppressant, a replacement for Halon 1301, produced at least 5 to 10 times more HF than Halon 1301 under similar fire conditions, however, there was no information available on the amount of thermal decomposition products generated during fire suppression with halocarbon agents in an electronic facility.
The Corrosion of Electronic Components by Hydrogen Fluoride (HF) paper published in 2008 describes in detail the HF corrosion and provides the test results showing the corrosion damage due to HF. While HFC-227ea is a very good fire suppression system, the HFC-227ea thermal decomposition byproduct, Hydrogen Fluoride, would cause serious and expensive short and long term extensive corrosion damage by the condensed Hydrofluoric acid. Hydrogen Fluoride corrosion severely affects computers, servers, switching circuits, and other electronics, connectors and electromechanical devices.
To prevent corrosion caused by Hydrogen Fluoride, as well as other chemicals, acids, salts, and water which can be deposited during the activation of fire suppression systems or rapid humidity changes, all the electrical and electronic hardware, boards and connectors should be sprayed or coated with SuperCORR A, an ultra-thin film lubricant and corrosion preventive compound that is non-hardening and will not crack. SuperCORR A is a water displacing non-flammable compound that will not interfere with any type of electronics or avionics and prevents corrosion.
While a fire suppression system utilizing HFE-227ea will put out the fire, SuperCORR A will protect and prevent damage to the electronics or avionics caused by exposure to the Hydrogen Fluoride produced as a byproduct during the fire. SuperCORR A Mil-L-87177, is also effective in preventing damaging corrosion by atmospheric gases such as Sulfur dioxide (SO2), Nitrogen dioxide (NO2), Hydrogen Sulfide (H2S), Ammonia (NH3), and Chlorine based gases (CL2) in Class III mixed gas tests and fresh or salt water systems.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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Maintenance engineers please help us to improve our product for you.
Corrosion Protection
SuperCORR A is the best lubricant with corrosion protective additives on the market and is widely used by the military and for industrial maintenance.
The website gives technical information and extensive user experiences in many areas. Currently SuperCORR A is supplied for maintenance purposes in large 16oz aerosols which are very convenient and economical for use in factories, offices or maintenance areas but are bulky for use by mobile service engineers where the cans need to be carried in tool kits.
SuperCORR A is such a useful tool for service engineers, displacing water and leaving a dry lubricating film which protects surfaces from corrosion under even the most extreme conditions that we are considering a smaller 3 or 5 oz pack which will be easier to carry and allow access in tight locations.
Tell us how you use SuperCORR A and let us have your views on whether a smaller can will make your job easier. We welcome your comments.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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An ounce of protection is worth a pound of cure
“An ounce of prevention is worth a pound of cure.”
Benjamin Franklin said that in 1736 and it is as true today as it was then.
One of the most important opportunities for savings today is the prevention of failures caused by corrosion. Corrosion leading to the repair of or the complete re-placement of failed parts or components, a pound of cure, which is preventable, equates to increased production costs and a decrease in the bottom line profits.
SuperCORR A is the ounce of prevention that will save your company money; man hour costs and parts in the re-pair or replacement of equipment that failed because of corrosion issues that are easily preventable. Whether it’s an electrical connection that failed because of corrosion which caused a cooling pump to shut down that caused a bearing to overheat and burn out that brought an entire production line to a halt or it’s the floor of an airliner that was so corroded that the aircraft was grounded for extensive repairs, corrosion is a serious and a very expensive problem. A problem that is preventable.
An ultra thin-film lubricant with corrosion preventative compounds that displaces water, SuperCORR A has been extensively tested on metals and electronics and has shown extremely good results in preventing corrosion.
The question to ask yourself is: What is the cost of NOT using SuperCORR A to prevent corrosion?
If you were able to say we are saving £100 a day by using SuperCORR A by not having a failure caused by corrosion would that be a good thing? How about saving a £1000 a day? A saving that would directly influence the bottom line.
You have essentially two choices:
1). Being proactive about corrosion and doing something simple and very cost effective to prevent it,
2). Do nothing and take your chances that the cause and the associated costs of the next lost production time are not directly related to a preventable corrosion problem.
Being proactive about corrosion and doing something that is cost effective and protects the bottom line is nothing but a positive. Remember the cost of lost productivity is directly related to lost profits.
CORR-EX corrosion control solutions have the answer to corrosion prevention for all industries and utilities.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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SuperCORR A Fully compliant with RoHS Directive
SuperCORR A is fully compliant with the requirements of the RoHS Directive 2002/95/EC – Restriction of certain hazardous substances in electrical and electronic equipment.
The restricted chemical substances are:
Lead
Cadmium
Mercury
ChromiumVI
Polybrominated biphenyls
Polybrominated diphenyl ether
For compliance equipment must contain no more than 1000ppm (100ppm for Cadmium) of these substances
SuperCORR A has been tested and confirmed to be compliant so can safely be used on already compliant electrical and electronic equipment which will remain compliant.
We can provide you with a Material Safety Data Sheets, independent laboratory reports, product samples and technical assistance.
For more information or advice please telephone us on +44 (0) 20 8281 6370 or use our contact form.
All products are supplied and supported by EnviroTech Europe Ltd. Manufactured in the United Kingdom and available on short delivery times through our dedicated team of distributors worldwide.
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