We have many models of solvent recycler and each one also has many options to suit your specific solvent(s), help automate the process and meet your own requirements. On top of that, what appears to be complicated legislation can mean selecting the right solvent recycler is confusing and can, at first, appear difficult. It’s not difficult though and here are a few simple questions to ask yourself to help you choose;
Is your solvent flammable?
99% of the solvent recyclers we sell are for flammable solvents, so you can fairly safely assume that your solvent is. That means you need a recycler suitable for flammable solvents. These are certified safe to ATEX regulations, meaning they have been tested to ensure they will not cause potentially dangerous sparks and thereby explosions.
Even if your solvent isn’t classed as flammable, it’s very likely that your solvent has a “Flash point” meaning a temperature at which it can become flammable (not to be confused with “Auto-ignition point”, a temperature where it can self-ignite). Many newer so-called “safe solvents” have high flash points between 60-100ºC.
For example; paint thinners, IPA, acetone, xylene, toluene, NMP, white spirit, solvent naphtha, MEK, ethanol and methanol would all require an ATEX flammable unit.
If you have chlorinated solvents, such as methylene chloride, these are likely to be non-flammable.
Our ATEX units, for flammable solvents, are given the designation of “D” in the model code.
Our non-flammable units are given the designation “S” in the model code.
If unsure, find your MSDS (Material Safety Data Sheet) and send it to us.
How much solvent do you use per day?
Irrespective of which size machine you buy from us, the complete cycle will generally take between 4-5 hours. So, if you buy a 15 litre machine, it will take 4-5 hours to treat 15 litres of solvent waste, and if you buy a 2200 litre machine, it will take 4-5 hours to treat 2200 litres. Some solvents distil very quickly, in less than two hours and certain automated equipment options speed things up, but generally 4-5 hours is about right.
Therefore, if you generate 30 litres of solvent waste a day then, most likely, you can get by with 15 litre unit, running two cycles per day.
Be a little bit cautious here, the amount of solvent you buy might not equal the waste you generate. The solvent will evaporate in your process, usually washing, but it will also collect some waste (paint, resin etc).
Machine sizes available are 15, 30, 60, 120, 160, 250, 400, 600, 1200 and 2200 litres capacity. It’s important to note that our size designations represent the holding capacity, so our 15 litre machine holds 15 litres, the actual total volume is 21 litres, for example.
If your factory works shifts, this may mean you have more working hours and can therefore run 3, 4 or 5 cycles per day, meaning you can use a smaller machine and reduce your initial purchase cost.
There are a few things which affect the cycle time (and, therefore; the clean solvent flow rate), but we will go into that in another post as it is quite complex.
Bag or scraper?
Bag machines use an anti-static plastic bag to line the recycler and keep it clean. At the end of each cycle you will have a container of a clean solvent and you can remove the bag, which will then contain your concentrated waste (such as paint) ready for disposal.
Bags are available for machines up to 160 litres in size. Beyond that size, the bags are simply too big to handle and, with the concentrated waste at the end of a cycle, too heavy to lift out.
Alternatively, scraper units have no bag inside. Instead the mechanically rotating scraper with brass spark-resistant blades keeps the boiler clean. Generally speaking, residues will be liquid at the end of a cycle and unloaded (automatically) by a valve in the bottom of the machine into a residue waste drum, although in some case it’s possible to completely dry the residues and tip them out from the machine like a concrete mixer – 120 litre units and larger have a gearbox to assist tipping.
Bag machines are cheaper to buy, but have the added expense of needing to buy bags and the need to place the bag inside the machine by hand. A bag can be used once or twice, depending on how much residue is in your waste. With a bag machine running costs still work out around 10-12p per litre recovered.
Scraper units cost more to buy but eliminate the need to purchase bags as well as the manual task of inserting of them. They also offer some more scope towards fully automating the cycles.
Scraper units are called “Dynamic” and have the designation of “Q” in the model name for example.
Automated or Manual?
Here it gets a bit tricky as there are some crossovers in machine options.
Our “Standard” machines have a simple control system; single batch with control of just time and temperature. This means that most automation possibilities are limited to “Semi-automatic” options; such as semi-automatic loading of waste solvent by pump.
With our “Professional” series of recyclers, it’s possible to programme in many steps or “phases” and fully automate the entire process, as well as run multiple batches, drying phases, cooling phases and much more. This means the operator can simply press “Start” and let the machine do the hard work. Professional units can be connected to dedicated tanks for waste solvent, clean solvent and waste residues with level controls to ensure the machine doesn’t run dry or over-fill any containers. Clean solvent can be automatically pumped to your own storage tanks or production equipment ready for immediate use.
We would say that 15 and 30 litre machines are fine to be loaded manually, but for machines 60 litres and larger we would recommend having semi-automatic or automatic loading. This keeps the machine clean and ensures the safety of the operator – removing the need to handle heavy containers of potentially dangerous solvent.
Of course, a lot comes down to your own budget. Although, with the recycler saving you considerable money on solvent purchase and disposal cost, some options, at least, are a worthwhile investment.
Standard units are designed with an “i” and Professional units are without the “i”, so a Di60Ax is standard ATEX unit of 60 litre capacity, whereas an S60Ax is a Professional, non-ATEX, 60 litre unit.
These are only the basic points and in all instances, we recommend you talk with us about your solvents and your contaminants so we can properly advise what specification you need to ensure it is safe and will do the job correctly to maximise your return. Send us an email, a contact form or hit the chat button on the right to talk to an expert.