Typically the parts we ultrasonic clean for plastic recyclers are the filters, the heat exchangers, the print rollers and other precision-engineered parts that have small holes or internal cavities that require cleaning. They are difficult, if not impossible, to clean through conventional jet washing, soak or other abrasive methods. They also tend to have small particulate contamination and are expensive to replace.
Let’s look at each in turn;
Oil filters from hydraulic or lubrication systems for fast-moving parts.
Filters – these come in all shapes, sizes and function but the most common filters in plastic recycling are;
Laser disc filters, or hot melt filters, used to filter remaining contamination from the plastic being treated;
Extraction filters used to keep the work environment free of dust, oil and other airborne contaminants;
Oil filters from hydraulic or lubrication systems for fast-moving parts.
Ultrasonic cleaning with the right chemistry for the relevant contaminant is ideal to remove small particulate from small openings and internal cavities typical of filters.
Heat exchangers – Most machines that work under high pressures and/or for long periods reach temperatures above their optimal working conditions and therefore require some form of cooling. This is done via heat exchangers, sometimes water-based, sometimes oil-based or even air-based coolers. By their very nature, the cooling media will create and then deposit particulate matter within the cooling mechanism. Over time this will reduce its effectiveness until it no longer performs its function. The removal of this contaminant is essential for it to continue doing its job. Ultrasonic cleaning reaches all surface areas of the part submerged in the cleaning solution, including internal cavities. With the right chemistry, any type of contaminant can be removed, from scale and rust to carbon and solidified oils.
Print Rollers – A lot of plastic is essentially packaging and therefore is ultimately printed upon to identify its contents or promote its producer. Many plastic recyclers offer some printing on the plastics they manufacture from recycled product. And this printing process on packaging material often users print rollers to carry the ink. These rollers are precision engineered to carry precise volumes of the ink but over time get dirty and cannot carry the necessary volumes of ink for good print quality. Ultrasonic cleaning is a well-proven method for restoring these rollers to full volume and optimal print quality.
All the parts mentioned above share common features. They are commonly highly engineered, high performance, high value and highly critical to the overall process of recycling plastic and converting to the desired end product. The alternative to ultrasonic cleaning is either replacement or highly laborious and time consuming manual cleaning that is usually only partially or temporarily effective.
If this sounds familiar because you either have the parts mentioned above or you have another cleaning issue then the chances are we can help, saving you time and money, improving the quality of your end product, and reducing your stress levels. Just get in touch and we’ll be happy to discuss your options, how we can help, and offer you a free trial clean to prove it will work for you.
A leading UK plastics recycler started having their Erema hot melt lasered filter screens ultrasonically cleaned instead of replaced after burning off. This resulted in annual cost savings on replacement discs that THEY estimated at £75,328.
In addition to these direct cost savings, their Engineering Support Manager reported increased productivity totalling over 20% from their recycling lines using the cleaned screens compared to the blocked old screens.
Other reported benefits included;
Improved quality and consistency of the finished product;
Increased reliability of production output;
Higher capacity allowing quicker delivery;
Improved ability to increase output in response to demand;
Higher customer satisfaction from a more consistent product.
As their Engineering Support Manager concluded…
All in all a massive win for us, reducing costs and increasing revenue simultaneously in a very competitive market.
Direct Cost Saving:
196 discs cleaned in 15 months = 13 per month
Each disc lasts at least twice as long with ultrasonic cleaning (minimum 4 times burnt/ultrasonic cleaning, compared with maximum 2 burnt alone) = 50% reduction in replacement discs
4 discs cost €7,000 = £1521 each at 1.15 exchange rate less cleaning and carriage cost = net saving of £965.74.
Annual saving = 13 discs per month x 50% replacement x 12 months x £965.74 net cost = £75,328
In 2 cycles a burnt disc gives 120 + 20T = 140, an ultrasonically cleaned one gives 120 +120T = 240T. This represents a 71% improvement, assuming a new and ultrasonically cleaned disc have similar productivity rates
A burnt disc lasts for 1 day giving 20T, an ultrasonically cleaned disc lasts an extra 4 days giving 120T = 30T per day. 20T to 30T per day is a 50% improvement in productivity
If an ultrasonically cleaned disc goes for 5 days giving 120T this is 24T per day, compared to 20T in 1 day from a burnt disc = 20% uplift in productivity
This is far more complex to calculate with variables such as duration of discs in various states of cleanliness and their respective production rates to arrive at like for like productivities. We have gone for the lowest level of improvement based upon a conservative interpretation of the figures.
Lower Capital Cost
Erema’s approved cleaning method for cleaning these hot melt laser filter screens is to burn off the plastic and other residue blocking the holes in a vacuum oven followed by a jet wash. These ovens cost nearly £50,000 and still only result in a limited extension to the life of these disc filters. Our customer already uses this burning technology but finds our ultrasonic cleaning process dramatically extends the life and productivity of their discs. If you either don’t want the cost or hassle of burning your discs in-house then Sonic Solutions can do the burning for you along with the ultrasonic cleaning. You just ship the filter screens to us as they are when they come out your melt block. We burn them, ultrasonically clean them and return them within a few days, ready to use again.
Lower Cost on other parts
If you are replacing other process parts like dust filters, heat exchangers, dies and rollers because they’re dirty you could save yourself thousands of pounds by ultrasonically cleaning them instead. We’re also cleaning anilox print and costing rollers, dust particulate filters and heat exchangers for this customer, improving the quality of their end products, production throughput and operative productivity.
What’s it used for?
Heat exchangers, intercoolers and radiators, whatever people like to call them, they kind of do the same thing. They come in all different shapes and sizes and are used totally different across the spectrum of industries. The reason we always try and find out what its used for is that it can better prepare us for the type of contaminant we might be facing. i.e a marine heat exchanger can be not only covered in general dirt and grease but also salt and scale.
Identify all possible contaminants
Just knowing what it’s used for isn’t enough to complete the picture, we need to know every possible type of contaminant we could be facing. Many times we have been told the only contaminant is grease and dirt, only to find out there is burnt on carbon inside causing serious blockages. Fail to prepare, prepare to fail.
Blockages or extreme build-up?
When heat exchangers arrive the first thing we do is check for severe problems, as a simple job can turn into a long hands-on labour intensive day. We usually see these types of thing in hard water areas, for instance, a coffee brewery in Bristol thought they just needed a simple de-scaling job but we found out later that the entire internals were blocked with a solid block of calcium deposits. 3 days later with hammer and chisels and some strong chemicals, we got the result, but usually this would have been around half a day at best.
What is it made from?
We have to know what the item is made of as it directly affects the types of chemicals we use and also how long we can leave it in certain ultrasonic baths for. For example, the soft easily bent aluminium fins on many radiators and intercoolers must be treated with extreme care both physically and chemically or risk irreversible damage.
Choosing the right chemistry
As mentioned some chemicals can harm certain metals, therefore we have to be sure that the cleaning solution will not only clean it but not damage it. This is where many, many years of experience in the ultrasonic cleaning business helps. 99 times out of 100 we know exactly what chemical will attack the contaminant whilst leaving the items completely unharmed.
Almost every type of heat exchanger has copper internal pipework for the transfer of water or oil, they also commonly have brass ends holding all the pipes in place. This is important to know because copper in heat and caustic chemical solution likes to leave the pipe and plate itself over the brass. The time is important because the quicker you can have the contaminant cleaned the less likely there is to be a transfer of copper to brass.
Monitor and rinse
Because elements of a heat exchanger are very prone to damage you must carefully monitor it whilst in the ultrasonic bath. Always checking for “fizzing” this occurs when aluminium reacts with an uninhibited alkaline caustic solution, so if you see little white bubbles rising up out of the parts then immediately take it out and rinse off as it is literally being dissolved into the solution. The other thing you must take care of is the way it lays in the tank. You must suspend it or have none of the fins touching any steel baskets or the tank base, irreversible damage will be done if not properly placed in the ultrasonic cleaning bath.
Rinse and repeat
We like to take the parts out of the tank periodically to give them a complete spray down and rinse so we can check to see if it’s necessary to stay in the ultrasonic bath. If we are not satisfied then it will go back in for further cleaning
We have a number of different methods when it comes to drying. A system we have found most effective is using high powered compressed air to blow between all the aluminium fins and down inside the copper pipework, this is brilliant at not only drying but also for removing any little tiny particulate matter that was left behind from the cleaning process. After the compressed air dry if we feel it needs further drying we put it in the drying cabinet for up to 1 hour until we are completely satisfied it’s water-free.
This is one of the most important factors because all the hard work done to achieve the brilliant cleaning result could all be undone with poor packaging. Protect the fins, strap it down and cover it with layers of progressively stronger material starting with foam or bubble wrap then carboard and preferably a lid on a crate of some sort, ensuring all void space is filled.
The difficulties of cleaning a fouled heat exchanger present a significant challenge to the maintenance and operation of chemical, petroleum and food processes. With internal contamination heat exchangers cannot usually be cleaned using normal methods (blasting, brushing, etc). But the combination of chemical, heat, agitation and ultrasonic power has proved an excellent way in removing industrial scale, calcium deposits, rust and carbonised oils from the tubes and other cavities within heat exchangers. Submersion in an ultrasonic cleaner with the appropriate chemical restores heat exchangers to optimal performance with no damage.
Welcome to the Sonic Solutions Knowledge Centre
Welcome to the Sonic Solutions Knowledge Center. This is the Go-To resource for Industrial Ultrasonic & Parts Cleaning and is updated regularly. If we haven’t already written about a particular aspect of Industrial Ultrasonic Cleaning, Pyrolysis, Thermal Stripping, Media Blasting or Jet Washing that you’re interested in, then please submit your enquiry here and one of our Industrial Cleaning Experts will take a look.
We approached Sonic Solutions after our parts manufacturers let us down and wasted precious time by supplying oily parts. Not only were they friendly, helpful and happy to rush our parts through - the quality was unbelievable! They arrived back at our factory just in time to not hold up production and we couldn't recommend them highly enough.
Our company AssetCool found the entire team at Sonic Solutions to be responsive and incredibly supportive of a new project. Their technical knowledge is superb, and they delivered exactly what they promised. We're very happy to recommend them to anyone with ultrasonic cleaning needs, and look forward to working with them again in the future.
I reached out with a problem to various companies prior to talking with Sonic Solutions, most were unhelpful. These guys insisted on the first trial being for free! The job was excellent and the turn around time very impressive. We are now setting up a monthly cleaning regime with them. A joy to deal with.
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