Frequently Asked Questions

Which materials can be used to manufacture hiTRAN® Thermal Systems?

hiTRAN® Thermal Systems can be manufactured from almost any metal or alloy that can be formed into wire. The most commonly used is 304 stainless steel and second 316 stainless steel. Also other stainless steel specifications can be provided. We have also supplied – Titanium, Tantalum, Hastalloy, Inconel, Copper, Bronze, Carbon Steel.

How are hiTRAN® Thermal Systems designed to meet each application?

The hiTRAN® Thermal Systems manufacturing method allows for the geometry (wire diameter, loop diameter, core wire thickness, density, length, etc,) to be custom designed to meet the specified duty, (pressure loss / heat transfer) for each application. Each job is therefore unique to the particular order.

Once a design is completed it can be reproduced again at any time from the specification code that is generated and displayed on the data sheet.

In what situations are hiTRAN® Thermal Systems not appropriate?

Generally hiTRAN® is not appropriate for some dirty fluids or slurry as the elements may cause blockage in the tubes. However, we do have many exchangers operating very successfully with dirty fluids. In general the very high shear rates created by the annular type flow regime with hiTRAN® elements reduces the tendency for particles to settle (deposition fouling). Reaction fouling will also be reduced as increasing the tubeside co-efficient will fundamentally change the wall temperature and therefore reduce reaction kinetics.Pour point problems can also be reduced on the same basis of wall temperature change, i.e. increase wall temperature but retain co-efficient

What is the difference between hiTRAN® Thermal Systems and Twisted tape?

Twisted tape is a lower cost and more limited performance enhancement method. Performance will vary dependant upon fit as tube bores vary with manufacturing tolerance. Twisted tapes are not usually sold with a performance guarantee. Technically, they rely on secondary flows set up through centrifugal effects but do not do as good a job of removing the boundary layer as hiTRAN® does. When including the whole cost of materials and construction hiTRAN® Thermal Systems usually provide a better cost/benefit ratio compared to Twisted tube.

The significant benefits of hiTRAN® Thermal Systems is the mixing effect they create by removing the slow moving fluid from the walls  of the tube  and mixing it with  the  fluid from the centre therefore  preventing both  the build up  of a thermally inefficient boundary layer and the deposition of particles within the tube. The benefits being;

  • Enhanced rate of heat transfer
  • No deterioration of heat transfer efficiency along the tube length
  • Reduced deposition keeping tubes cleaner and in service longer

Can hiTRAN® Thermal Systems be used only in a proportion of the tube?

Yes, for example hiTRAN® can be put just in the first 10% or 20% of the tube.

The first 10% or 20% of the inlet tube length will be in the sub-cooled region, this being the case then the fluid will be in  single phase and our programme can support this.

How are products transported?

CALGAVIN is very flexible and can organise the transportation for the client by road, sea or air.

Can CALGAVIN provide references where hiTRAN® Thermal Systems has been used before?

Yes, please see our References and Case Studies section on the website. We also offer the opportunity to specifically look up projects we have completed for your own company or within your country.

How is hiTRAN® installed into new equipment?

Where hiTRAN® is put into new equipment, the exchanger fabricator will carry out the installation after completion of the bundle. CALGAVIN provides all instructions needed, fitting equipment and method of securing the elements. Many fabricators now have experience in fitting hiTRAN®, however if a fabricator would like some assistance on the first installation we can provide this support. Depending on the size of job and location we may need to recover costs for this service. Read more about Installations of hiTRAN® here.

Can hiTRAN® Thermal Systems be Retro fitted?

hiTRAN® are easily fitted and removed. They are flexible along their length for ease of installation even where access is restricted. Elements are simply guided into place along the axis of the tube. Exchanger tubes must be in a clean condition before the elements are installed as it is important that the loops on the elements have contact with the tube wall.

Generally elements are installed in the same direction as the flow. CALGAVIN will provide instructions and diagrams to clarify how to secure the elements in place together with the necessary securing wires, joining fittings and securing rods.

Can air-cooled heat exchangers be retrofitted with hiTRAN® Thermal Systems?

For air cooled heat exchangers with ‘Plug Type’ headers or other exchanger designs where access is restricted hiTRAN® core anchors can be used.  Elements are usually supplied in continuous lengths of up to 8 meters. For long tubes they may be joined and installed in series.

What are the maximum and minimum tube diameters?

hiTRAN® Thermal Systems are manufactured to suit all tube diameters from 4mm to 150mm.