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Flow Coating and its Benefits to Your Transformer

flow coating

Flow Coating is a process where liquid chemicals, such as paint or adhesives, are sprayed through an airbrush or in some cases through a stencil onto the item being coated. When this is done in production it is called flow coating and can be used for items like transformers. The benefits of flow coating are that it creates a thinner coat of liquid on your object so you can achieve a high level of coverage while using less material.

Flow coating is also used in transformers to reduce the effect of micro-corrosion. By reducing the cavity area through flow coating and the resulting micro-grinds, you reduce the reaction between minerals in the steel member and water in a corroding environment. The result is a longer life for your transformer.

There are two main types of flow coating: Spray and Stencil

Spray flow

Spray flow coating involves spraying liquid on a flat area of the transformer and then letting it set up in the open air for a period to harden. This method has limited application since it can only be done to transformers that are large enough to hold more than one object at one time.

Stencil flow

Stencil flow coating is where the stencil is put onto the part, and then the paint is sprayed on top of it. This allows for a more uniform application, which can be useful when painting a design onto your transformer.

Flow coating can be used on a wide variety of materials including aluminum, steel, copper, and to a lesser extent tin. It is often used in the power distribution industry where the maintenance of the equipment is critical.

Flow coat process

The process itself involves the application of a fluid onto a surface while the fluid is moving through the air. The velocity at which this occurs must be carefully controlled; too fast and it will have difficulty sticking to an uneven surface. Too slow, and it may lose its qualities after a few applications. This is why the product is often applied in thin layers which are sprayed on in a controlled manner. Usually, the product will stay on for about two to three minutes before being scraped off and the process repeated.

The process itself can be compared to an artist painting on a canvas because the fluid itself acts like paint while creating an air bubble that traps it on the surface of the material. The item itself is then heated to somewhere between 300 and 500 degrees Fahrenheit. This causes the fluid to become vaporous while a vacuum pump draws it up, leaving the desired coating behind without any damage to the surrounding equipment.

Although flow coating was used in space travel, it has not yet been adopted by many companies in general. It is highly cost-effective and effective yet it requires specific types of equipment that few companies can afford or justify using. Perhaps with the time that will change as more and more people become aware of its potential uses.

Over the next five to ten years, companies will likely use flow coating as a means of keeping their transformers in top condition. It is important to note that the use of flow coating should not be used as a means of replacing traditional methods. It is meant as an additional way to achieve the same goal through a different process.

Because flow coating can be used with such a wide variety of materials and equipment, it has the potential to open up new doors for developing technology. By increasing the lifespan of various items, the need for replacement is eliminated, reducing costs and saving both time and space.

Components of the flow coating process

Vacuum chamber

The vacuum chamber is a large, air-tight container that traps air within the tube while keeping it away from the material being coated. This prevents contamination and allows for more control over the varying sizes of materials that flow coating is compatible with.

Electric coils

These coils are found inside of the vacuum chamber and allow for the creation of an even, low pressure along with creating a vacuum in which there is no air movement. As fluids pass through the coils, they remove heat and redirect it toward the material that is being flow coated.

Vapor nozzle

This is a metal or plastic fitting that directs the escaping gas to different areas of an item. It is used to direct the gas in one direction while ensuring there are no air bubbles.

Thermo crystal

Used as a means of keeping track of how long the coating has been on its surface. These components are found in the vacuum chamber. They are temperature-sensitive devices that show how long the item has been on in several different ways. The device contains a heating element that is used to warm the crystal used to monitor its life. The crystal will be heated and then cooled, eventually showing a specific number of seconds left on it.

Other equipment

A thermostat is used to control the application of liquid and thus provide an even coating throughout the process while also keeping track of it once it is complete.

Because flow coating can only be done to flat objects, it is not used very often in the industry. Its main benefit for transformers is that it increases their life span of them by reducing micro-grinding and corrosion.

Another benefit is that flow-coated transformers may have a thinner substrate, so they are lighter. However, this can also be achieved with a thicker substrate by using anodizing or paint to increase the weight of the transformer.

Things to consider

There are some potential downsides to using flow coating. As mentioned before, stencils require a bit more work because it is harder to coat your transformer accurately and uniformly with stencils than with spray methods.

The other disadvantage of flow coating is that it can be time-consuming. Flow coating involves more time than spray coating because you have to wait for the paint to dry before you can move on to the next part of your job. Also, because the process is so labor-intensive, flow-coated transformers can double in cost compared to the same-sized transformer that has been spray coated.

For these reasons, flow coating is not commonly used in the industry though its benefits are still valued. It can be useful when you want a uniform coating on an object or if it's small enough that it can only be sprayed onto one item at a time. This article will discuss methods for using flow coating and what you should consider when deciding to use this method for your transformer.

Using flow coating to reduce micro-corrosion is suitable for electrolytic and silicon steel types. Silicon steel is a very common material used in transformers, but it can be catalyzed by water. Hydraulic fluid reacts with silicon steel to create hydrogen, which can corrode the internal surface of your transformer. Because of this, you want to make sure you keep your transformer clean. Using a flow-coated transformer will reduce the amount of water that is inside your transformer, and you will be able to keep it clean more easily.

For this reason, it is best to use flow coating on smaller transformers that can fit in one object box at a time. The cost of flow-coating may increase due to the increased labor required, but it will give you a longer life for your equipment.

Spray coatings are more commonly used in industry. They are usually applied to transformers that have to be assembled one at a time, and they have flat surfaces.

3D Stencil paint is also available for use with flow coating. It allows the user to place stencils on 3D structures and then paint liquid on top of them. This saves time compared to using 2D stencils or sprays of paint.

Flow coat clear

Flow coat clear is a technology utilized to--among other things--increase the life of transformers. It utilizes nanotechnology that acts as an internal "shield" to protect the transformer from high electromagnetic fields and static charge. These shields for transformers can become worn over time leading to poor performance and a shortened lifespan, as well as undesirable performance with power surges.

In this article, we will discuss one of many flow coat options, which is an impregnation process called Flow Coat Clear.

Flow coat clear is an impregnation coating that can be used to protect various components in power grids and other power applications. As a single-component coating, it can be applied as a liquid or a film application. Flow coat clear can also be used in the vacuum forming of products, as well as in plating processes.

Flow coat clear implementation

Implementation of flow coat clear is measured in nanometers (nm). It acts as a shield that prevents the formation or buildup of static or electrostatic charge. This also eliminates the possibility of corona discharge, which occurs when high voltages are introduced to the transformer. These two basic effects can cause various issues with transformers and their safety systems, including arc faults.

As an impregnation coating, flow coat clear is applied to the surface properties that will not change due to electrostatic charge buildup. This coating creates a barrier to prevent electrostatic charge buildup.

Real-world use

The largest transformer ever made is housed at the San Diego Gas and Electric (SDG&E) 500 kV Substation. This particular transformer is shielded by an advanced process of flow coat clear, which prevents the build-up of static charge, thus increasing its lifespan and efficiency. Flow coat clear has been implemented with the SDG&E facility in the past and continues to be used. This has led to a reduction in power outages, which results in lower utility costs for consumers.

In addition to being used with electric transmission lines, flow coat clear can also be used with power grids and distribution lines, as well as with high-voltage generating systems. It is an effective solution that not only decreases the cost of utilities but can also increase the lifespan of these systems.

As stated previously, flow coat clear is applied in nanometer thicknesses. One nanometer is equivalent to one billionth of a meter. The measurement process involves using gigahertz surface wave analysis, which includes the use of different-sized pins to measure the thicknesses. Flow coat clear can be applied through the use of either a liquid or spray film application process.

One of the steps to applying flow coat clear involves applying a pretreatment that activates and polarizes the surface, making it ready for coating. This is performed by using flow coat clear's liquid form. Once the pretreatment is done, a vacuum-forming step is then performed to form the coating in a uniform film on the surface. This completes the application process for flow coat clear.

The type of application used will determine whether the coating can be sprayed or sprayed and vacuum formed. Spray application will allow for a smoother, more uniform layer to be produced, and it also allows for finer spraying of flow coat clear than spray and vacuum forming combined.

Although the application of flow coat clear is one way to prevent the buildup of static or electrostatic charge, other preventive methods can be used. These include grounding a transformer so it will not create a ground potential, as well as using antistatic devices to keep the transformer at an even potential. Antistatic devices are typically electric grid surge protectors that make sure that a surge never reaches the transformers, which would otherwise affect their performance and lifespan.


The use of flow coat clear is not a new technology; it has been used for more than 20 years. It has been used to protect transformers in high-voltage power grids as well as processes and devices that use high voltages. This includes the use of impregnation spray as well as reactive spray and vacuum forming processes. The effectiveness of flow coat clear is proven by its applications in power grids and its ability to increase the lifespan of an electrical part, thus decreasing costs to consumers.

Flow coat clear is used to decrease the cost of power in many different ways by reducing outages and maintenance costs. By using flow coat clear, a transformer's lifespan will increase and it may even be possible to reduce some types of maintenance costs. It also reduces the cost of electrical parts because they can last longer and avoid breakdowns, increasing their efficiency as well. Because of the reduction in cost that comes with flow coat clear, utilities can keep revenue neutral instead of having losses due to bad transformers.


The application of flow coat clear is not difficult and can be performed by a range of people and companies like USM. Depending on the application, the use of a professional may be encouraged, from maintenance control to power engineers. The effectiveness and long-term cost savings should convince any owner or manager to apply flow coat clear to any system that utilizes transformers including distribution and transmission lines, as well as devices with high power.

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