FAQ

 

General Questions:

 

Thermal conductivity is the property of a material to conduct heat. It measures the ability of a material to transfer heat. Heat transfers at a higher rate across the materials with higher thermal conductivity than across materials with lower thermal conductivity. A material’s thermal conductivity is primarily depends on its own molecular structure.

The thermal conductivity units is W/(m·K) in SI units system, and BTU/(hr·ft⋅°F) in Imperial units system. 1 Btu/(hr·ft⋅°F) = 1.730735 W/(m·K)

The definition of thermal conductivity is that under a given circumstance, the amount of heat energy transfers through 1 m2 in a material from one side, where is 1 Kelvin higher in temperature, to another side 1 meter away.

Heat transfer coefficient is a quantitative characteristic of convective or phase transition between a fluid medium (a fluid) and the surface (wall) flowed over by the fluid. It is used in calculating the heat transfer, typically by convection or phase between a fluid and a solid.

Heat transfer coefficient is depend on many factors like type of fluid flow, nature of fluid flow, property of solid and fluid, thermal boundary conditions and so on, it is not the property of solid alone or fluid alone, but the complex property of the whole heat transfer system. The thermal conductivity is only one of the factors that can improve the heat transfer coefficient.

The heat transfer coefficient units is W/(m2•K) in International units system, and Btu/hr•°F•ft2 in Imperial units system.

As stated in the answers to question #1 and #2, heat transfer coefficient is the property of the whole system and cannot reflect the heat transfer ability of a material. Thermal conductivity, on the other hand, is the property of one material only. It can measure a material’s ability of transferring heat. So, we use thermal conductivity as parameter of our heat transfer compounds.

Using heat transfer coefficient by some companies simply do not show us the heat transfer ability of their products.

A material’s thermal conductivity is primarily depends on its own molecular structure.

Supplementary materials are the additives to the heat transfer compounds to meet customers’ special requirements such as fast curing, low chloridion and high working temperature.

Applying heat transfer compounds, we can dramatically improve heat tracing system's performance.

For example, in a steam pipe tracing system, the tracing pipe and process pipe have extreme limited contact area or even no contact. Most of heat is transferred through convection. The thermal conductivity of air is about 0.025 W/(m•K) or 0.0144 Btu/(hr•ft⋅°F). But the thermal conductivity of HTT products is at least 6 W/(m•K) or 3.467 Btu/(hr•ft⋅°F), which is at least 240 to 400 times better than that of air. So, applying heat transfer compounds in between can establish highly efficient thermal conductive channel. It is estimated that only one tracing pipe with our HTT AP650 heat transfer compound can replace 3 to 4 bare heat pipe.

For mineral insulated electric heat tracing cable applications, heat transfer compounds are also needed to support high temperature heat tracing requirement.

Using HTT series heat transfer compounds can significantly reduce customer's initial construction cost and overall operation cost.

No.

Our heat transfer compounds are non-toxic, and will not contaminate our environment. But our products are compounds and inedible.

We have professional team who can provide total heat transfer material solutions for industry customers.

We team with our customers to develop solutions to address their problem in heat tracing, heat exchange, heat exhaust and cooling systems. We have experience in process optimization. So, we are not just provide thermal conductive materials, we provide heat transfer solutions for our customers.

No.

Our HTT AP series is inorganic and alkalinity compounds. It will not corrode the surface of carbon steel. HTT SSP series is also an series of inorganic compounds, but it is neutral, and non-metallic materials. NH series is neutral high polymer material and has no corrosion on metal surface.

Corrosion potential is the characteristic or property of metal and nonmetal surfaces to lose electrons in the presence of an electrolyte. During the process of corrosion, two electrodes are formed spontaneously, a cathode and an anode. Corrosion potential is the electrode potential that the material surface acquires automatically in its environment.

The corrosion potential of a material is a useful parameter in estimating the present and future corrosion damage and detection, as well as monitoring the electrochemical reaction causing corrosion, both at the work site as well as in the laboratory.


Professional Questions:

 

That’s a big and important question.

Different kinds of thermal conduct materials have different impact to metal surface. Heat conducting materials can be classified to carbon based, metal oxide, and metal (powder). These are highly (thermal) conductive materials. But they may have (electric) potential corrosion.

Adhesive made of high polymer material is neutral and corrosion free to all metal surfaces. Most of inorganic adhesives are alkaline to neutral. After eliminating chloridion, they have extremely limited corrosion impact to metal surface and no corrosion to stainless steel surface. But be cautious that, chloridion in materials is corrosive to all metal surface. And almost all inorganic adhesives have chloridion.

Under strict quality control, our company removed almost all chloridion during the production process of HTT SSP series heat transfer compounds.

It will always be recommended to consult a PETT staff before you finalize which model you want to buy.

It is much based on your application situation. Please consult PETT technical engineer or refer to our solution for sulphur operation or jacket-type heat tracing replacement solution for asphalt production.

Our NH series non-hardening products are made of high polymer materials and fundamental thermal conductive materials. Thermal conductive materials are inorganic which will not be aging and malfunction. Our high polymer adhesives are very stable under normal working condition, especially within range of the working temperature. It will withstand for more than 10 years after installation.

NH series’ shelf life is indefinite. Please make sure it is firmly sealed when it is not in use.

If NH series compounds had a long time exposure in an overheated environment, the high polymer materials will be carbonized. This will change the physical and chemical property of the compounds. For example, it will become less sticky, powdered and exfoliated.

No.

The products of NH series are chemical corrosion resistant to the metal surface. The SSP series is specially designed for using on stainless steel surfaces. The SSP series compounds have reduced chloridion to a extremely low level (≤ 25ppm). So, SSP series also has no corrosion to metal surface.

1. Do not expose to organic solvent or strong oxidizing agent.

2. Do not add water or any other addition

3. Do not used in an overheated environment. It will cause irreversible damage and greatly shorten the service life NH series heat transfer compounds.

NH series and inorganic series (AP, SSP) have different formula, and production process. So, they have different features and application scenario.

AP and SSP series product is inorganic. They wider range of working temperature. It can support up to more than 1290℉ working temperature. But most of inorganic heat transfer compounds are alkaline and water soluble. NH series has very good hydrophobic nature. It remains pliable and can resist vibrate or liner expansion difference which occurs in a temperature dynamic environment. Because NH series and support as low as -40℉, it is often used in cooling system. But NH series can only support up to 450℉ working temperature.


Process Questions:

 

1. Do not expose to organic solvent or strong oxidizing agent.

2. Do not add water or any other addition

3. Do not used in an overheated environment. It will cause irreversible damage and greatly shorten the service life NH series heat transfer compounds.

4. It is recommended to use HTT U tracer kit or cover with glass fiber cloth and prevent the contact with insulating layer.

Working in a dynamic temperature environment is challenging for hardening heat transfer compounds. Because different material has difference liner expansion rate, the changing in temperature may damage the contact between the hardening compounds and the surfaces the compound should stick to.

For this kind of scenario, we recommend our NH series. Its pliability feature can support any dynamic thermal expansion application. But if you need this feature in a higher working temperature (>450℉), such as solar thermal electric power generation, please contact us. We can provide customized solution for you.