The addition of small amounts of plasticizers and hardeners makes an entirely new line of polyurea Polymers that can be used in various industrial coating applications.
Researchers from Missouri State University have modified the most well-known synthetic polymer, polyurea, to attain exact control in the flexibility of a novel group of polymers. These can be used in various applications requiring thin coatings with different physical, protective insulation, and aesthetic properties.
Polymers like polyurea are extensively used for coatings in various manufacturing areas such as shipbuilding, construction of buildings, the petroleum industry, and aircraft and automotive manufacturing. Researchers across the world are seeking ways to expand their use and properties.
But, creating new polymers with new features can be a complex and costly technological process, claims Maxim Stanley, a chemist in our research group.
Stanley and his team discovered that the most efficient method to create new polymers that have properties that can be easily modified is a modification of existing cheap polymers available in huge quantities. They discuss their successes in modifying polyurea to control its properties and properties of insulation coatings within the publication Doklady Physical Chemistry.
They began their study using two industrial polyureas, which were elastically different. The researchers looked into the chemical issue of identifying additives that could create a variation between different properties from the soft surface of one initial polymer and the stiff plasticity of the other.
The researchers found that they could cause the polyureas structure to break and heal by the addition of varying amounts of fluorine as a hardener as well as a chemical plasticizer with a combined rate of not less than 2% in weight, enabling them to control the elasticity of the material across an extensive range. In technical terms, the ‘elastic modulus is a measure of the force needed to break the material that can be adjusted between 22 and 172 Megapascals which is an extremely wide variation.
“We were amazed that these tiny chemical modifications could achieve the desired, continuous range of polyurea grades that range from rubbery to harder. He says that one distinct feature of their work is that these altered polyurea samples were made using high-pressure spraying technology invented by the US firm, ArmorThane- Polymer technologies, which two researchers employ.
This polyurea spraying technology can create seamless and flawless monolithic coating with your desired thickness onto materials in any shape or arrangement.
The team hopes to expand its research efforts to other polymers while benefiting from the relationship with ArmorThane to develop commercial applications.
The protection of offshore structures from corrosion and abrasion damage is a constant and costly issue for those who manage these structures.
Both rough and corrosion-prone The marine environment is not kind to marine structures like offshore platforms and rigs as well as ocean-going vessels, each of which is a major investment for the businesses that operate these structures. Every activity and structure that are in the marine environment is affected by corrosion.
The marine environment is also extremely hard on surfaces and coatings and coatings, both in the way they wear and how they’re applied. The areas that are most affected are superstructure, deck ballast tanks, chains, or anchor wells. These areas are exposed to saltwater as well as chemical substances and abrasion. (Learn about the negative effects of salt on Salt Limits to Avoid premature coating failures.)
One method to reduce and lessen the effects of certain kinds of corrosion is by applying flexible surface coatings made of a material that is impervious against chemical damage from petroleum products and salts. A corrosion barrier must have the ability to withstand and flex and be resistant to the wide variety of chemicals that can affect maritime structures.
To increase security for people moving through vessels or offshore structures, spray-applied surface coatings with anti-slip properties make decks safe and provide walkways.
Guarding the deck of a platform from abrasion Applying coatings designed specifically for marine structures employed within offshore structures used in the oil and gas industry can help reduce the impact of drilling operations. (Read the details of an offshore facilities investigation in Tightrope: The Identification of limitations to coatings specifications.)
An oil rig deck with 14-meter lengths of drill pipes laid out before being pulled through the deck and then pulled up to drilling operations is susceptible to many scratches caused by the abrasive. The majority of the surface coatings are easily abrasive and expose the metallic substrate exposed to corrosion.
To prepare the work areas for coating treatment, the deck’s surfaces should be an abrasive blast to remove the existing coatings and smooth the surface to ensure the best bonding to primer and a protective coating. Prime, as well as the protective coating.
The Zn-rich prime is initially applied to the metal surface, then an additional spray primer is quickly sprayed. The most effective primers for this application include no volatile organic components (VOC) properties and can be swiftly spray applied.
To ensure the best protection, a thick layer made of polyurea will be applied on the primed surface to an approximate depth of 3000 millimeters (3 millimeters). The final coating is selected due to its resistance to extreme weather conditions and its excellent flexibility and strength. Polyurea can cure quickly, allowing workers to walk on the surface in just a few minutes. This means the facility will be restored to operation sooner.
When applying any treatment to a surface, the most important factor to consider is minimizing the time required to complete it. Spray coating can allow for quicker application with less disturbance to the operation. The rapid setting coating can be set in just 6 minutes. In contrast to other coatings, Pure polyureas aren’t adversely affected by ambient temperature or moisture in the application. This is a major consideration when it comes to offshore operations.
Protrusions of Decking that are coated In the places where pipes and other devices can penetrate the deck regions of offshore structures, It is crucial that liquids don’t run through the pipes seen below. Most offshore rigs protect these holes with a rubber boot attached to the pipe and deck. But, the rubber in both the boots and adhesive may be damaged through UV light and salt exposure within a the space of a few months.
To prolong the life of the deck boots for penetration, the butyl rubber and the steel surfaces adjacent to it are generally cleaned and scuffed before applying a suitable primer. It is essential to ensure that all loose coatings oil, dirt, and dirt are removed thoroughly before applying the new membrane. In the same way, equipment pipes, and deck surfaces must be blocked away to protect against the risk of overspray.
The application of the polyurea coating with an amount of 2000 microns or more and then extending 50mm across the pipe and 100 millimeters onto the deck forms an air-tight, weather-resistant, flexible and weatherproof interface to all deck penetrations and provides the durability that is required for industry professionals in the marine industry.
Polyurea Coating Properties Pure polyureas form when the liquid isocyanate is mixed at extreme pressure using an amine-driven solution for resin. They are reactive because the double covalent bond that binds carbon atoms to oxygen and nitrogen atoms can be broken easily into single bonds within this more solid tetrahedral structure around carbon atoms.
Certain kinds of polyureas can be found in a double-component solution mixed at extreme temperatures and pressure (3000 Psi, at 65oC) using a specially-designed spray apparatus. When applied to the surface, the superior chemical cross-linking produces a strong yet flexible coating. The denseness makes the coating virtually impervious to abrasion, water, and chemicals.
Pure polyurea coatings are cured quickly to create a smooth surface that can be walked over without harm within less than a minute. Another benefit is allowing polyurea to be sprayed up to 6000 microns (and higher) on a sloped or vertical surface without sagging and flowing. Its surface strong polyurea coating is simple to clean, maintain and recoat when needed.
While Epoxies and paints create an unbreakable hard shell, The flexible nature created by pure polyurea coatings permits them to move in line with their expansion or contraction structure when temperatures fluctuate.
Tabletop surface coating, tank coating, quick coating, winter coating, coat of arms…. I mean, it just feels like there are thousands of epoxies out there. How do you choose which one you go with? Which one do you choose for which project? That’s a lot to consider.
Here’s the secret.
All the epoxies that you see out there. Well, 95 percent of them boil down to just four different types. Let me clear the air and explain each one.
In order to explain this best, let’s talk fruit!
I’ve made a little graph quickly for me to better explain everything…we’ve got an apple, an orange, a banana and a bunch of grapes. Each one of these is going to represent a type of epoxy.
Also on the other side, you’re going to see a pie, a beautiful glass of orange juice, some bread and, well, a grape juice. Now, keep in mind, all of these are fruits, but they’re all very, very different and have different applications. An apple is delicious in pies and orange. Well, that’s a good way to start the morning. Bananas makes my all time favorite bread, banana bread. If you’d like to send me some banana bread, I’m not going to be mad at you.
And grapes. Well, grapes make grape juice. Yes, these are all fruits, but not each one of these works for all the other applications that we have over here. For instance, I don’t want anything to do with banana pie and I don’t want to deal with grape bread either. They would just get hot and it would be like a nasty Ushery fruity situation. That sounds terrible.
All right. So each one of these fruits, well, it coordinates to a certain type of epoxy.
If we look at our apples and we can call that our surface coating , you might have heard of this as a tabletop. I’ll represent that with T tabletop or orange. Let’s call that are more UV resistant. That’s going to have that extra juice in there to make sure it doesn’t yellow nearly as quickly as our bananas. We can call that our quick hearing. And then lastly, we have our grapes on here. Let’s call that our deep pores, these four types of epoxy.
That’s it. I mean, that’s 99 percent of the epoxy that you see out there on Amazon online and all these YouTube videos. They’re one of these four types. So what are these four types of poxes good for and what are they not good for? Well, for surface coatings and tabletop a poxes tumblers counters. That stuff is perfect for it’s made for that for UV resistant stuff. That’s where art comes into play. Photo encapsulation stuff you want to protect and have it not yellow.
So quickly now quick curing epoxies are perfect for sealing wood for fast coatings, when you need to keep going on a project and you don’t want to wait twenty four hours for something to cure. And then deposit boxes are obviously perfect for river tables, large castings, and you still want beautiful clarity. Now these four types of epoxy are great, but this isn’t enough information. I don’t think. I think you need more details. I’m not going to be able to talk through all the other competitive products out there because, well, I don’t have all those details, but I do have details.
So let’s use our products as the examples. take a look at this board i have written on and I’ll talk through these products. All right. Here’s our chart. Here are our four epoxies. Clear cast. That’s our surface coating or tabletop amazing clear cast. Plus, that’s our UV resistant one amazing quick coat. That’s our fast curing.
And then amazing D for you guessed it hard for possie on this side. I’ve got some attributes that we should talk about. Depth, speed, air release, UV resistance, hardness and then applications again, because that’s really why you’re here. All right. So for depth’s, for amazing clear cast, an amazing clearcuts. Plus, you’re looking at about three eights of an inch, not quite half of an inch for amazing quick coat. It’s an eighth of an inch.
Remember, that’s a fast setting epoxy. So we’re dealing with more exothermic there. Camper’s deep and for making deeper. Well, that’s two inches. That is ideal. All right. Let’s talk speed through you off didn’t on that. I definitely do. You got you. All right. Let’s talk speed for amazing clear cast, an amazing clear cast. Plus, you’re looking about about a twenty four hour tax free time. Depends on your temperature. So always keep that noted.
Allow four to six hours. That’s fast. Hence quick coat, although your pour can take time. Twenty four to seventy two to get that tax free. Depends on your temperature again. Is this fully cured. No, that’s still five to seven days or three to five days depending on your product. Next up, air release. Here’s the thing. I’m going to shoot you straight. We formulate all of these to have amazing air release for their applications.
I’ve put the best over here for amazing deep for so that you realize a two inch pour is going to take a lot of air release in order to get that crystal clear. That’s why medicore is water thin so that the bubbles can get out of there. But keep in mind, it’s water thin. It’s not going to do a good job coating a tumbler. Go ahead, pour water on your tumbler and let me know how much of it stays on UV resistance.
I think you can predict this one. The best on this board is definitely the UV resistant epoxy. Wonder why. I will say, though, we do formulate every one of our poxes, though, to have fantastic UV resistance as much as possible within that formulation. No, but if you’re looking for that extra juice, you want to ask plus second to last. Let’s talk about hardness. That’s sure. Hardness on the D scale.
What is that?
It’s a lot of acronyms are 80 on the short scale. That means that they’re really hard and really durable, but not that far behind is amazing clearcuts. Plus with seventy five dollars, these things are as hard as like construction work or hard hats. There’s nothing soft here, folks.
Why should you care about hardness? Well, the fact that we’ve made these really, really strong just means that it’s going to be a lot more durable. It’s got to be harder to dig up your projects and scuffling. Last but not least, Lippestad assistance is the application. When should you use this stuff? Right. So for a surface coating epoxy like Almazan Clear cast, this is for, believe it or not, surface coating, small castings, countertops, stuff where you’re going to pour on a flat surface or around a surface that you’re going to rotate consistently and get a beautiful thane coating for amazing clearcuts.
Plus, we’re looking at art coatings, photo encapsulation, something where you want that project to last as long as possible because it has maybe sentimental value memories to it or it’s going to be outside a lot like a Tumblr where that you’re taking around here. That’s great. If you need that extra UV resistance for Amazing Quico, this is where we’re sealing wood for me. I use this to seal up a board before I pour a deeper foxe on it.
That means that I’m not going to have any air bubble issues or moisture issues. And since it’s only going to take four to six hours, I can keep my project moving for amazing deeper. Well, I hope it’s obvious by now, but River Table’s large castings things where you’re really pouring thick and you need that extra time for the air to release and you need the extra time to make sure it doesn’t exothermic turn yellow and cross. So there it is.
Now, you know, the four different types of epoxy when to use each one and kind of what are the features and benefits of each. If you want to see more content like this, if you’ve got specific questions, I want to know about them. Put them in the comments below and answer them.
Today we’re going to cover lot’s of scientific words such as resin, polyurethane and epoxy. You will probably have lots of questions like are they the same thing? Are they not the same thing? What’s your thing and how does ArmorThane fit into this? What about polyester? Is polyester a thing? I don’t know but i am going to answer all of these questions…
Let’s jump in!
We have resin. That’s the huge overarching term. There are organic resins, things like gums that trees produce. We’re not talking about that.
We’re talking about synthetic resins. That’s what you know and love underneath resin. We have thermal plastics and then thermosetting plastics. So thermoplastics, things that can be melted or injection molded or formed, things like acrylic, Delran stuff you probably don’t deal with. Plus we covered these terms in our last post.
So let’s ignore them!
So thermal setting plastics are usually liquid one or two parts that become solid and stay solid. They don’t meltdown. That’s where we find our good old friends, polyester epoxy and polyurethane.
Let’s quickly go through each. So polyester resin was one of the first synthetic resins that we came up with. And to be honest, it wasn’t that great. It’s brittle now. It’s just using boats with a bunch of fiberglasses to reinforce it. So let’s move on.
Next was epoxy. Hey, that word sounds familiar. A pox, a type of resin wonder that that’s much stronger, much more solid. We enjoy that!
But it just becomes a hard plastic one time. And that’s it. Not a lot of variety. They’re perfect for river tables, tumblers.
You know this stuff. You love it. Come on.
After epoxy, they invented polyurethane. This is much more versatile. It can be foam. It can be rubber. It can be hard plastic. This stuff is wild and crazy ArmorThane that you use in your truck bed. That’s polyurethane.
Some of the phones that you have in cushions and seats are polyurethane woodturning bulls. And Penlington, the beautiful clarity of clear sloth. That’s polyurethane. I know what you’re saying.
Troy, you don’t care about science. All right. No big deal. That’s enough of that. Let’s jump into two things. Epoxy and polyurethane. Why and when you should use each one of them. It’s been all right. So for categories, I want to talk about his products, time, moisture, and ease of use.
Those are the huge, huge main differences between epoxy and urethane. So let’s jump into each so the products that are epoxy products of ours, you’re going to recognize these amazing clear cast, the new amazing clear cast plus and the even newer, amazing deep or all of those are poxes. So the time aspect of epoxy is it has a pretty linear, a pretty steady here schedule. That’s why when you’re mixing up a batch of epoxy, you have a thirty-five to forty-minute open time, and then you have a cure time of about twenty-four hours and then a full cure of about five to seven days.
It’s linear; it’s pretty steady. That’s very normal. It can still be a shorter time, like a quick coat or a much longer time. Like an amazing or, but it’s pretty linear now when it comes to poxes and moisture. No big deal. They don’t mind it. If you’re doing a woodworking project where epoxy is going directly onto the wood painting, use epoxy, it has a much higher tolerance for that type of moisture in the last category, ease of use for epoxy, there is a high tolerance.
What I mean by high tolerance, it’s forgiving. All right. A little bit of an ounce off here, there is a larger batch, or I’m not sure if I got everything mixed perfectly, perfectly. It’s still going to harden up. It’s still going to be fine. Now, what about Urethane coating? Well, a couple of different things here as far as products go. This is clear Slowes RC is another popular one. Flex, Flex Rubber’s, our flex foams.
There’s a ton of urethane products we have. They’re amazing. Let’s talk about their cure schedule, their cure time. What happens in that? Well, usually, with urethane, we have a lot more variables. We can change, and we can manipulate things accordingly. So what you’ll see is nothing happening, nothing going on. Nothing’s happened. Suddenly it’s cured. I couldn’t resist. I’m sorry. So these things cure quickly, usually on a short schedule.
So you’ll be going steady, and then bam, it’s cured, or you’re going pretty steady, and then really quickly it’s cured fast. That’s why we suggested woodturning applications because you can pour a blank, get it in the pressure. Part D demoed it in ninety minutes and got going with an epoxy. It’s a little bit harder. Here’s the thing, though, as much as we love how fast those things kick back, not a fan of moisture. I could put a little drop of water into your thing, and it would start to foam.
So should you use this within woodworking projects? No, not unless your wood is completely stabilized. Now, as far as ease of use of your Thain’s, well, there are a little less forgiving there. You are still forgiving, but a little bit less. That’s why you’re often going to see on the labels one to one by weight or two to one by weight. This is a little bit more of exact science, and you got to pay attention to it.
All right. So there you go. Hopefully, that clears much information about the world of resins and the epoxy world within that, and the polyurethane world within that, and the polyester resin world. It’s a lot. I know. Let us know if you want me to do another one of these. I’ll go even deeper to the extent.
Visit ArmorThane to learn how you can purchase and use these amazing chemicals!
Look out, super glue and paint thinner. Thanks to brand-new dynamic materials developed at the University of Illinois, removable paint and self-healing polymers quickly could be family products.
U. of I. materials science and engineering teacher Jianjun Cheng, graduate student Hanze Ying and postdoctoral scientist Yanfeng Zhang released their operate in the journal Nature Communications.
” The crucial advantage of using this material is that it’s catalyst-free and low-temperature, and can be healed numerous times,” Cheng said. “These are very good products for internal cracks. This can recover the fracture prior to it triggers significant issues by propagating.”
Other self-healing material systems have concentrated on solid, strong products. Nevertheless, the brand-new research study utilizes softer elastic materials made from polyurea, among the most extensively utilized classes of polymers in durable goods such as paints, coatings, elastics and plastics.
After the polymer is cut or torn, the scientists push the two pieces back together and let the sample sit for about a day to heal– no extra chemicals or drivers required. The products can heal at room temperature level, however the process can be sped up by treating at a little greater temperature levels (37 degrees Celsius, or about body temperature level). The polymer bonds back together on the molecular level nearly as highly as before it was cut. In fact, tests found that some recovered samples, stretched to their limits, tore in a new location rather than the recovered spot, evidence that the samples had healed totally.
The researchers utilize commercially readily available components to create their polymer. By slightly tweaking the structure of the particles that join up to make the polymer, they can make the bonds between the particles longer so that they can more quickly pull apart and stick back together– the key for healing. This molecular-level re-bonding is called dynamic chemistry.
Researcher Hanze Ying demonstrates the making and self-healing residential or commercial properties of a brand-new dynamic polymer. Credit: Anne Lukeman Dynamic chemistry has actually been checked out in some other polymers, however those materials tend to be for specialized applications or lab settings, rather than the traditional polymers used commercially. By focusing on customer products and utilizing easily available active ingredients, the scientists hope that manufacturers could easily integrate dynamic products.
” We just buy business materials and blend them together, no elegant controls or unique device,” said Cheng. “It’s a really easy, low-cost, affordable procedure. Anybody can do this on any scale.”
Now that they’ve established the chemistry needed, the scientists are checking out how dynamic polyurea might boost various applications. For instance, they could tweak the mix so that a polyurethane coating or paint could be detachable.
” In some areas, when it’s not essential for the coating to be long-term and you desire it to be removable, this chemistry might be applied to existing coating materials to make it reversible,” Cheng stated. “In basic, polyurea and polyurethane are widely used. This chemistry might modify existing materials to make them more dynamic, healable.”
Research chemists at U.S. Naval Research Laboratory (NRL) have developed and patented a transparent thermoplastic elastomer armor to lower weight, inherent in a lot of bullet-resistant glass, while maintaining superior ballistic homes.
Thermoplastic elastomers are soft, rubbery polymers converted by physical means, rather than a chemical process, to a solid. Subsequently, the solidification is reversible and allows harmed armor surface areas to be fixed ‘on-the-fly’ in the field.
” Heating the material above the softening point, around 100 degrees Celsius, melts the little crystallites, allowing the fracture surfaces to meld together and reform through diffusion,” stated Dr. Mike Roland, senior researcher, NRL Soft Matter Physics. “This can be achieved with a hot plate, akin to an iron, that molds the freshly forming surface into a smooth, flat sheet with minimal result on stability.”
Already, NRL researchers have evaluated the use of polymeric products as a coating to accomplish improved impact resistance of difficult substrates. Applying polyurea and polyisobutylene layers boost the ballistic performance of armor and helmets, and accomplish higher ballistic efficiency and mitigation of blast waves.
By using a variation of employing thermoplastic elastomers, NRL scientists are able to recreate remarkable ballistic properties of polyurea and polyisobutylene coatings, with the added advantage of the product being transparent, lighter than standard bullet-resistant glass, and repairable.
“Because of the dissipative homes of the elastomer, the damage due to a projectile strike is restricted to the effect locus. This implies that the affect on presence is practically inconsequential, and multi-hit protection is achieved,” Roland said.
Ever since the creation of the first concrete floor, humanity has searched for a way to protect and beautify the surface. Epoxy coatings have been around since the 1930’s and have since taken off to become one of the most popular protectors of concrete floors. Fairly new to the party, polyurea polyaspartic coatings have quickly become the darlings of those who want a fast dry time. Let’s examine each of these contenders and see how they stack up against one another.
Epoxy Coatings
Epoxies are resin polymers made of epoxide units, cyclic three-atom ether rings containing an oxygen atom, and two carbon side-groups. The triangular units are electronically strained and are therefore very reactive. Normally, epoxy resin is produced by reacting bisphenol A and epichlorohydrin, but variants popular for concrete floor applications involve novolac and aliphatic epoxy resins. A typical application consists of an epoxy primer, a color base coat, and two polyurethane layers.
Benefits of Epoxy Coatings:
Not unreasonable in price
Creates a hard, decorative finish
You have many finish options, including color and mix-ins
Very tough
Unyielding to chemicals
Good adhesion — won’t raise
Long pot life, allowing it to be applied with a manual gun
Drawbacks of Epoxy Coatings:
Less flexible and less resistant to abrasion
It can be moderately difficult to apply in hot or cold conditions
It has a longer drying time
Has potentially hazardous vapors, although recent formulas have fixed this
May not be colorfast — subject to fading or yellowing from UV exposure, though many formulations include UV protection
It cannot be applied when the temperature is below freezing
Polyaspartic Coatings
First introduced in the 1990s, polyaspartic coatings arise from aliphatic polyisocyanate reacting with polyaspartic ester, a diamine. The compound is known as an aliphatic polyurea, which is quite different from conventional polyureas and, in many ways, better. By tailoring the relative amount of the ester, scientists can craft different polyaspartic coatings with various features. For garage floor applications, the ester is the main component, ending in low emissions and quick drying. When applied to grey concrete floors, polyaspartic floor coatings produce a glossy, almost watery tone that customers can color. In some applications, decorative chips are spread on the still-wet topcoat.
Benefits of Polyaspartic Coatings:
Easier application in a wide variety of cold and hot conditions
Hard, smooth finish that is stain- and scratch-resistant, great for high-traffic spaces
Clear and non-sticky when hard
Fast-drying times cures to full strength in 20-30 min
Colors and decorative chips possible
Colorfast, even when utilized to slightly damp concrete
Low VOCs and odor
Low viscosity gives it good wetting capacity on concrete but requires a reduced rate of solids
High, controllable film build-up
Not likely to bubble from outgassing
Drawbacks of Polyaspartic Coatings:
The relatively new product, professional application suggested
Short pot life needs the use of automatic application guns
Two to three times more costly to purchase and apply
Must avoid high moisture vapor emission rate conditions when utilizing
We might have to thin the first coat for better adhesion
It doesn’t hold up as well to battery acids
Very slippery when wet, so a top aggregate such as chips suggested
The purpose of water treatment is to cleanse drinking water to satisfy federal government guidelines for quality and produce wastewater effluent that has a minimized effect on the environment. Water and wastewater treatment plants (WWTPs) use different phases to speed up the natural processes that purify water and wastes. Whatever methods, equipment, or technologies are used, pumps are a necessary element for moving raw water, waste water, sludge, and effluent within various processes. With high global demands for energy, the industry is looking for pumping systems that take full advantage of performance, reliability, and cost-effectiveness.
Decreases in pump efficiency can be caused by mechanical, volumetric, and hydraulic losses. Mechanical loss is related to moving elements of a pump, such as bearings and glands. Volumetric loss refers to leakage of fluid from the discharge side of the pump to the suction side. Hydraulic loss is triggered by the frictional forces developed in between the fluid and the walls of the hydraulic passage, velocity, and the modification of the fluid direction. Therefore, smooth pump walls reduce circulation variations and, subsequently, the energy required for the pump to move the fluid. This post goes over the use of state-of-the-art lining innovations to increase the performance of pumps while protecting their internal surfaces from disintegration and deterioration.
Result of Pump Surface Roughness The two categories of pumps most typically used at WWTPs are the centrifugal and positive displacement pumps. Centrifugal pumps are more common since they are easy and safe to run under a broad series of conditions. The operating concept of moving a fluid by means of mechanical actions can be detrimental to the internal components of the pump. For instance, centrifugal pumps are vulnerable to damage and efficiency destruction by cavitation, where vapor bubbles form in the low-pressure region directly behind the turning impeller vanes. The collapse of these bubbles can damage the impeller and deteriorate the pump casing.5 Pressure drop control in pumps is typically limited, and cavitation can not be prevented. Over time, cavitation can produce severe erosion-corrosion issues.
The roughness of pump surfaces impacts the fluid flow.
As the roughness increases, the laminar circulation becomes unstable and shifts into rough circulation. Erosion-corrosion mechanisms are intensified under unstable circulation conditions. Surface area flaws in the form of small protrusions or anxieties, such as corrosion pits, deposits, and weld beads, can trigger disturbed flow on a smaller sized scale. Although small, such problems suffice to start the erosion-corrosion processes in the form of impingement, cavitation, and even entrainment in the presence of solid particles.6 Under these situations, energy losses will occur and lead to more decrease in effectiveness of the pumping system.
Alternatives for Pump Efficiency Improvements. Standard options to mitigate the unfavorable repercussions of turbulent flow programs include devices design adjustments to reduce hydrodynamic forces and using exotic, erosion-resistant alloys as materials of building and construction. However, due to cost, relieve of construction, and accessibility, the products of construction most frequently picked are cast iron, carbon steel (CS), or stainless steel (SS). The resistance of these conventional products to rust and disintegration is relatively low; and in the case of SS, localized corrosion can still take place when its protective passivation movie is damaged or exposed to chloride environments.
Another method to minimize erosion-corrosion and enhance performance is to isolate the metal surface area from its contact environment with a lining. Numerous benefits of this option can be mentioned:8.
1. Lining pumps made of CS with fit-for-service coatings provides an economical approach of improving the rust resistance of standard materials when compared to using corrosion-resistant alloys or cladding.
2. Lining products are readily offered if needed, even at short notice.
3. Lining products do not add substantial weight to the pumps. Sometimes, linings can facilitate a reduction in weight because of a reduced corrosion allowance for the metal based upon lower awaited disintegration and deterioration rates.
4. Efficient lining application methods enable much shorter project preparations and less equipment downtime.
A wide variety of corrosion-resistant coating innovations can be used for securing the interiors of pumps. Some of them include glass flake, thermosetting polyurethane, and nonsolvent-free epoxy coatings. Making use of a few of these coatings is limited by the presence of volatile organic substances (VOCs) in their structure, which may trigger health and safety issues. Others have bad mechanical adhesion and lowered resistance to erosion and rust. Due to technological advances in protective commercial linings and repair composite materials, it is now possible to utilize polymeric materials for coating systems with exceptional resistance to erosion-corrosion and cavitation. These high-technology linings can efficiently boost pump efficiency.
Coatings Designed with a Unique Combination of Properties. Pump efficiency curve.State-of-the-art coating innovation has resulted in coatings with special chemistry. Enhanced erosion-corrosion resistance, hydrophobicity, and hydraulic smoothness are qualities that allow high energy effectiveness and optimum pump efficiency to be achieved. These coatings are essentially created as a blend of lube agents and abrasion-resistant fillers. The fillers are utilized to reduce erosion-corrosion wear, whereas a mix of various amines offers a smooth finish and low electronic affinity towards water molecules. As a result, the beginning of rough circulation is delayed, which consequently lowers skin friction.
These coatings are solvent-free, epoxy-based, and free of VOCs so health and wellness concerns are minimized and item shrinkage is avoided. Coating systems can be applied in fairly thin layers to circumvent any flow restriction issues. Linings have been reported with a surface roughness of 0.09 µm vs. 1.19 µm for polished SS. The ultra-smooth surface, in addition to self-levelling and hydrophobic properties, lessen turbulence and surface area tension.
These high-performance coatings were tested for service physical fitness in alignment with globally recognized approaches such as those supplied by ISO, NACE International, and ASTM. Such coatings have actually reported adhesion worths greater than 31 MPa (4,500 psi) on grit-blasted moderate steel when tested in accordance with ASTM D45419 and ISO 4624.10 Atlas cell testing, in accordance with NACE TM0174,11 is likewise utilized to figure out the suitability of these coatings in immersion service. Chemical testing using ISO 2812-112 is another test required for assessing the resistance of coatings to the range of chemicals found in the WWTP. Some of these chemicals include chlorine, ferric chloride (FeCl3), and sodium hypochlorite (NaClO).
In addition, these protective coatings can be checked for potable water contact in agreement with the U.K. Drinking Water Inspectorate.
Pump Efficiency. The efficiency of a centrifugal pump is normally explained by a graph that plots the pressure produced by the pump over a series of flow rates (determined in terms of head). Likewise, its performance is consisted of on a common pump performance curve. The effectiveness of a pump is the ratio of the pump’s fluid power to the pump shaft power. A centrifugal pump has a best effectiveness point (BEP) where it runs the most cost-effectively in regards to both energy effectiveness and upkeep. Continually running a pump at its BEP is difficult due to the fact that systems typically have changing demands.4.
Power vs. flow curve.
A pump efficiency test in 1989– carried out by the National Engineering Laboratory (then part of the United Kingdom’s Department of Trade and Industry), a global reference in fluid circulation screening that represents the most thorough pump test facilities worldwide– recognized performance enhancement of a centrifugal pump that was lined.14 The tests were carried out in a single stage, end-suction centrifugal pump with 10-in (254-mm) suction and discharge branches. The pump (in an uncoated condition) performed at 1,300 rpm, had a capability of 875 m3/h (5.55 countless gallons per day [mgd] at 26.5 m head, and total peak performance of 83.5%.14 The exact same pump was then protected with a lining to demonstrate that boosted pump effectiveness could be attained.
The coating examined was a solvent-free, two-component epoxy system, specially developed for improving the performance of fluid-handling devices and securing metal surfaces from the effects of erosion-corrosion. This coating was used in 2 colors to validate the 2nd coat had actually been evenly used and completely covered the first coat, and to make future assessments much easier to assess. The two pump tests were carried out in a normal closed-loop system using the same protocol, with a series of flow, head, and power readings taken throughout a wide circulation range. The pump effectiveness curve, developed with calibrated test instrumentation and traceable to nationwide requirements, was then plotted (Figure 1).
FIGURE 3 Erosion-corrosion results to the impeller.
Checking results of the covered pump showed a 6% increase at peak performance (Figure 1). Substantially, there was little change to the pump head/flow characteristics, meaning the coating increased the pump performance while maintaining the original head/flow properties. The power decrease of 5.1 kWh was attained at responsibility point.
History. A state federal government water and wastewater treatment business in Bahia, Brazil employed a lining to safeguard a centrifugal pump and increase its performance. This water and wastewater business is responsible for operating and keeping 431 water treatment systems and 94 wastewater plants throughout more than 360 municipalities in Bahia. The water treatment plants supply drinking water for 11.9 million individuals, whereas the wastewater plants provide sanitation to ~ 4.8 million people.15.
Coated impeller
.In 2006, the plant maintenance personnel of among these plants discovered anomalies in their process, primarily due to mechanisms of erosion-corrosion and cavitation in the pumping system. The possession, a Worthington † split-case centrifugal pump with a capability of 1.080 m3/h (6.84 mgd), was installed in the pump system to catch raw water from the São Francisco River for treatment and shipment to the neighborhood. This pump was experiencing localized metal loss and corrosion, mostly in the volute case and impeller (Figure 3). Numerous repair options were thought about by the asset owner. The choice was made to utilize a 100% solids epoxy-based lining to secure the harmed internal parts of the pump. The work was performed by authorized applicators following the lining maker’s product guidelines for usage, as follows:.
– The malfunctioning parts were abrasive blasted to achieve surface cleanliness requirements of NACE No. 2/SSPC-SP 1016 and ISO 8501-1 (Sa 2 1/2),17 with a minimum typical profile of 3 mils (75 µm).
– The surface areas were checked for salt contamination and dealt with accordingly.
– The surfaces were washed down with appropriate cleaner/degreaser to remove residual blasting debris and any grease impurities.
– The thickness of the pump wall was restored according to the original equipment producer’s pump repair standards using paste-grade epoxy products.
– The protective coating was by hand applied in 2 coats of contrasting colors to obtain a minimum total dry movie density.
– The lining was allowed to cure for chemical service (Figures 4 and 5) and more inspected for connection.
Coated volute
Results The pump was returned to service. After 6 years of continuous use, the pump was opened for evaluation by upkeep workers. Some erosion wear and metal loss from moderate cavitation could be seen on the volute surface area (Figure 6), but the lining remained in good condition. The plant supervisors were satisfied with the results. The pump had been protected against cavitation and corrosion for 6 years. The procedure is now part of their preventive upkeep program.
The pump likewise was tested to examine both the energy intake and the cost of power intake savings associated with running a more efficient pump. Direct measurement of motor current was chosen to properly evaluate improvement of the pump’s effectiveness. Electric current readings were taken on the motor of an uncoated and covered pump under the exact same conditions. The readings for the uncoated pump revealed an average of 72 A with 440 V, whereas readings reported an average of 66 A for the layered pump. The results showed an amperage decrease of 8.33% and a consequent reduction in the power usage, because these variables are directly proportional.
These outcomes showed that this coating technology efficiently added to decreasing losses by safeguarding the surface versus the impacts of erosion-corrosion and cavitation. Creating a smooth, hydrophobic finish also resulted in a reduction in energy consumption. Ever since, the exact same efficiency-enhancing polymeric coating was applied to eight of the 12 pumps at that pump station. The results can be reproduced for other types of pumps.
Erosion locations on the volute after 6 years of service. Conclusions.
The polymeric coating innovation proved to be a suitable alternative for improving the performance of the pump, as well as protecting it from deterioration, with very little maintenance work throughout its designated life time. The technology is recommended for protecting pump surface areas and boosting pump effectiveness within water and wastewater plants.
As anticipated, cavitation effects were not eradicated however minimized; nevertheless, the boost in fluid flow efficiency represented an instant saving in power usage, one of a lot of significant business expenses for water and wastewater treatment plants.
