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Thermal insulation is an essential process across a range of industries, but for many of its applications, there are also practical considerations to do with cost, as well as efficiency and adaptability. This is why thin thermal insulation is becoming a key area of research and development.
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A heat sink is a passive heat exchanger. This means it transfers heat from an object to a coolant, either air or liquid. This coolant then dispels any heat generated by the object.
Heat sinks are used in many essential electronic devices, including as central processing units in computers and in power electronics.
A good heat sink must be made of the right kind of material to perform its function well. Along with the material of the heat sink itself, another crucial aspect in its operational effectiveness is the thermal interface between it and the component.
Mica, with its natural conductive qualities, is an ideal material for use as a thermal interface and insulator of heat sinks.
Heat sinks must prevent overheating in electronic devices and components. To do this, they must be made of certain materials, which have a good degree of thermal conductivity.
Most devices using power electronics will require environments with controlled temperatures. Otherwise, they risk overheating, which can then affect performance or, more seriously, become a safety hazard.
Essentially, the heat sink acts as a pathway for any heat being generated to dissipate away from the device or component. This requires an optimum speed, to dissipate the heat from the source at the same rate as the source is generating it.
In fact, optimisation is the key to success of any heat sink system. This impacts on the choice of materials, along with essential aspects such as, complexity, size, mass and cost.
Therefore, while choice of materials is crucial, there are other factors to consider too.
The most common heat sink materials are aluminium and copper alloys.
Aluminium alloy provides the starting point for many heat sinks. This is because aluminium alloy has high thermal conductivity, but is also easy to manipulate mechanically because of its softness.
Another option is to bond copper and aluminium together, with aluminium remaining the dominant part, because of it lighter weight. This combination has been increasingly used in heat sinks for computers.
However, while aluminium surrounded by a copper plate can be effective, the copper and aluminium do not always bond together as tightly as necessary, making this cheaper option a less reliable one.
Another growth area is in carbon-derived materials, combined with aluminium. This takes advantage of aluminium’s lighter weight but is more conductive than copper.
Natural graphite composite materials are also on the rise in heat sinks. Again, the advantage here is weight.
Generally, in terms of performance, traditional aluminium and copper heat sinks perform most consistently.
The heat sink has fins in its design that provide the necessary surface area to dissipate the heat. The fins act to cool the source of the heat and the heat sink itself. Consequently, the efficiency of the fins is an important aspect of the heat sink’s performance.
Heat flows through the fin, the temperature decreases from its base to its end, from a combination of the heat sink’s thermal resistance, heat lost due to convection and the temperature of the fin.
The arrangements of fins in a heat sink also affects its performance. For example, heat sinks with pins that are either elliptical, cylindrical or square are fairly commonplace. Another type is a heat sink with a straight fin, running the entire length of the heat sink.
Colour can also be a consideration, since black surfaces with a matte finish radiate heat more efficiently than bare metal with a shiny surface.
The most effective heat sink for a specific function will combine good thermal management with suitable mechanical design, taking into account practical needs and cost effectiveness.
The heat losses from a power electronics device must get across different interfaces between materials. A component will have a casing, for example, so any heat must move from this to the surface of the heat sink. There is also the heat transfer which must occur between the heat sink and its surroundings.
Each of these transfers will have its own thermal resistance, and the combination of these will affect the efficiency of the entire system.
Therefore, the task of the relationship between device and heat sink, taking these things into account, is to minimise the overall thermal resistance or maximise heat flow.
The choice of materials acting as a thermal interface can help greatly in this function.
In computer processing units, for example, the thermal interface material will be positioned between the processor and the heat sink.
Used with other parts, mica components are an extremely effective thermal interface in heat sinks. These components include mica washers for use with heat conductive paste, and mica wafers for mounting semiconductors to heat sinks.
This is because mica is lightweight but strong, and highly adaptable. It is a technically superior insulator, able to withstand both intense electric fields and high temperatures.
As specialists in thermal management solutions, Elmelin can provide you with a range of mica-based products for heat transfer and insulation purposes.
Please phone us now on +44 20 8520 2248, email sales@elmelin.com, or complete our online enquiry form. We’ll get back to you as soon as possible.
Thermal management for electronics is critical where electronic components produce significant amounts of heat. Where this is the case, effective thermal management will prolong the working life of these components and also increase their reliability. Such components include power transistors, CPUs (central processing units) and power diodes used in the power electronics industry. For thermal management, mica offers adaptability and flexibility combined with high resistivity and stability. As an insulating material which will not conduct electricity, it is well suited in a wide range of applications in electronics.
Thermal management materials are essential in automotives, and this applies to emerging and developing automotive technology as much as it does established applications.
Investing in R&D is investing in creativity, but why then invest in creativity? The Royal Society points out to invest in R and D is to ultimately increase the stock of knowledge.
When it comes to product innovation and development, or process refinement and improvement, the role of the R and D department is critical.
Elmtherm is a range innovative high temperature insulation products, based on microporous technology. Designed to perform consistently at a peak level of excellence, Elmtherm has several applications across different industries, including foundry and steel, aerospace, petrochemical and fire protection.
This microporous material is durable with superior thermal insulation characteristics. It is used primarily as a lining material, protecting products, equipment and technology from heat incursion, and so ensuring their safety.
The technology underpinning Elmtherm is separation technology. This involves small particles of silica, dispersed through an area, to the extent that they create small openings, or micro-pores. These micro-pores have tiny diameters of less than two nm, or nanometres.
When combined, these micro-pores create molecular sieve membrane. This sheet has a low density but an extremely effective porous structure.
What does this mean in practice?
Used in high temperature insulation, microporous material blocks conductive, convective and radiant forms of heat transfer.
Microporous technology restricts conductive heat transfer through minimising the contact between molecules, impeding their ability to transfer energy, from one molecule to another.
The structure of microporous sheets also creates pockets of trapped air which stop the free pathway of air, thereby containing convective heat transfer. This means there is limited or no heat transmitting through the microporous material.
For combatting heat transfer from radiation, microporous material has infrared opacifiers loaded into it to reduce the occurrence of radiant heat transfer. These added substances help make the material impervious to light-generated heat.
Elmtherm is highly energy efficient, helping reduce operating costs in the industries in which it is applied, while ensuring good temperature control through its excellent thermal stability.
Where there are issues to do with consistency and safety in performance, Elmtherm can help.
Elmelin produces four different grades of Elmtherm microporous material for high temperature insulation.
Each of these grades comes in a different ranges of thickness, which determine their heat transfer capabilities.
Elmtherm 1000 and 1100 are microporous in composition and can withstand maximum temperatures of 1,000°C and 1,100°C respectively. They come in thicknesses of between 3mm and 50mm.
Elmtherm 1400 and 1600 grades combine microporous materials with ceramics to form effective heat shields, designed to withstand temperatures of up to 1,400°C and 1,600°C respectively. Thickness for these grades depends on their specific application.
High temperature insulation is an essential requirement across different industries and sectors, but microporous technology is proving to be a widely applicable, adaptable and highly effective solution.
The low thickness but high strength of Elmtherm make it well-suited for applications where safety, efficiency and energy saving are all key requirements.
Low weight combined with high compression strength means microporous solutions can both protect equipment and other materials while ensuring peak performance.
Elmtherm lines ladles in foundries, ensuring that they can safely hold molten metal at intense temperatures. This type of lining increases the capacity of ladles by 10% while having a positive impact on energy conservation, offering improvements in this area of around 50%.
For furnaces, Elmtherm helps with even heat distribution, and also protects against heat loss, to the tune of 30%. At the same time, because of its thinness, it is a more efficient insulator than other, alternative board materials.
In aluminium launder systems, Elmtherm contributes to the speed and efficiency of the casting process, where speedy transfers between furnaces are critically important. Elmtherm optimises the movement of molten aluminium between smelting and casting processes, saving on heat and time.
Elmtherm is also used to line tundishes, to assist in continuous casting operations; and is also found in kilns and rotary kilns.
Microporous insulation is an industry standard for aircraft, when it comes to ensuring the lowest possible thermal conductivity and keeping things as lightweight as possible.
Elmtherm provides essential thermal protection for aircraft auxiliary power units and flight data recorders. It also provides heat shield material for thrust reversers, and flexible insulation inside aircraft engines.
In the form of panels, it can also insulate galley ovens on aircraft, as well as providing wings with fire protection.
For pipeline materials in the petrochemical and other industries, protection against extreme heat and fire is vital, as process piping is inevitably going to involve highly inflammable materials.
Because it is lightweight and flexible, but also very strong, Elmtherm is an ideal lining solution for process pipework. It is used in power plants, the petrochemical and cement and glass industries.
With fire and elevator doors playing essential, strategic roles in passive fire resistance, ensuring they are as fire-proof as possible is essential.
Elmtherm has proved ideal for this form of insulation, being lightweight but highly fire-resistant, and easily adaptable to a range of situations and locations.
These microporous insulation boards are a safe, modern alternative to asbestos, opening up new possibilities for high performance, high temperature insulation in buildings management and safety.
Elmelin’s Elmtherm range of microporous high temperature insulation solutions is highly adaptable across a very broad spectrum of industries and sectors. We have only touched on a few key examples here.
Discover more about Elmtherm and how it could benefit your business and your industry by calling us on +44 20 8520 2248. Alternatively, please email sales@elmelin.com, or complete our online enquiry form. We’ll get back to you as soon as possible.
Mica components are one of the many ways in which we can harness mica’s natural heat resistant and dielectric properties to serve a whole range of industries. Mica has a natural, structural stability, making it an ideal manufacturing solution when it comes to producing heat resistant gaskets and washers, along with other vital components.
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As a supremely versatile material, mica comes in a variety of forms, suitable for different applications, across a diverse range of industries. Elmelin’s range of mica products reflects this versatility. Mica tube is one such product, and in