When people hear the term "process plant" in industry, they probably spontaneously think of long pipelines, large containers or silos, and transport lines. The media conveyed are just as diverse as the applications. However, special attention is paid to those places that require flexible connections.
The solution for flexible connections is first of all a hose. This hose must compensate for heat loss - should the medium temperature deviate from the ambient temperature - and be thermally insulated to prevent the flowing medium from cooling down. However, if the desired medium temperature is higher than the ambient temperature, heat losses must be equalized by additional measures.
The required heat can be supplied by a heat transfer medium or an electrical heating system. In this case, these media are transported in small hoses or pipes mounted on the surface of the medium transport hose or pipe. Another possibility: double-walled pipelines in whose interspace the heat transfer medium flows.
When looking at piping systems, for example, one problem of such applications quickly becomes apparent: leakage. Steam leakage or condensate outflow are among the manifestations caused by stress, aging or lack of maintenance. In the case of hoses that are operated with high bending frequency and constant movement, among other things, only electric heating systems ultimately provide a reliable solution. However, even solutions with electric heating systems quickly reveal limits in terms of technical implementation. The high rate of movement requires the heating system to be extremely close to the medium hose for heat transfer.
Conventional solutions use heating tapes from industrial trace heating, laid parallel to the hose and resting with one of the broad sides on the medium hose. Under torsional and bending stress, however, such designs tend to lose contact between the heating tape and the substrate. The heat flow is interrupted. Consequence: Heat transfer is insufficient.
Application Praline production
Just how problematic such an interruption can be can be seen in a special application: the production of chocolates. Chocolate consists of a mixture of a wide variety of fats, oils, emulsifiers and sugars. Both the individual substances and the raw mass are extremely temperature-sensitive, and the processing temperature range is very narrow. It is precisely here that it is necessary, for a wafer-thin chocolate coating, to bring the mass into a homogeneous and fine-grained state, which can be conveyed at the boundary between pasty and almost liquid from the storage container via heating hoses to the spray nozzles.
Temperature fluctuations have a direct effect on consistency and appearance, especially on the functionality of the spray nozzles. If the temperature is too low, granulate-like particles can form and clog the nozzles. Despite the use of particularly high-quality control technology combined with conventionally built heating hoses, frequent stoppages occurred. The cause proved to be the uneven heating of the "chocolate" medium by means of heating tapes. The use of a hose with a novel heating concept significantly reduced the number of production stoppages.
The design of the electrical heating on the surface of the medium hose is remarkable. A characteristic feature of the Templine heated hose system is the medium hose with its elastic braiding of temperature-resistant yarn, into which four heating cables of protection class I are braided. The sophisticated design of the braided layers demonstrates a high degree of flexibility and always nestles seamlessly against the medium hose when bent as well as when twisted (torsion). At the same time, the yarn plies permanently pull the heating cables into surface contact with the hose as a result of the system. The heat transfer is close to 100 %.
The direct heat transfer into the medium guarantees the user an energy saving of up to 30 %. Extreme thermal stress on the hose, heating cable and subsequent layers due to temperature peaks, which would lead to accelerated aging, is avoided. At the same time, the design of the braids and the spiral arrangement of the heating cables - similar to a spring - prevent premature aging during permanent movement, since tensile and compressive stresses are reduced to a minimum.
As a result of this development, service lives are extended by up to 40% according to initial experience. The concept of economical and effective energy use was also pursued in the thermal insulation of the Templine heating hose. A newly developed thermal insulation as a combination of compact and foamed-on plastic layer achieves a thermal conductivity value of 0.02 W/mK at + 20 °C reference temperature. The advantages of this are smaller hose diameters, lower surface temperatures and the additional promotion of uniform heat propagation on the medium hose.
Application ready meals
An application from the food industry uses two advantages: smaller design and low temperature differences along the hose. Ready meals contain ingredients in a dried or granular state. Dryness during storage and processing are important. Composition up to individual packaging is achieved by metered delivery of the ingredients from storage containers connected to nozzles via heated hoses, which deliver the material to a conveyor line. The metering devices perform a high number of movements in a very confined space.
Important task: Granules and dried components in the hoses must be protected against condensation and clumping and conveying standstill must be avoided. In the past, this task could only be solved by high heating power (protection against undertemperature due to asymmetric heat propagation), comparatively short service life (due to high mechanical aging in a short time) and complex control technology. With the installation of the templine heated hose system, it was possible to surpass the previous service life after only a short period of use, and to significantly reduce energy consumption on selected production lines. Medium hoses made of polytetrafluoroethylene (PTFE) are FDA-certified for contact with foodstuffs and, thanks to their non-stick properties, are easy to clean when changing products.
Last but not least: The mechanical protection to the outside. To be mentioned in the front line: Abrasion, blunt pressure or sharp edges, torsion and tension. Here, braiding made of polyamide and aramid fibers has proven its worth for years. These form the outer cover of the Templine heated hose system. The range of hose diameters extends from DN4 to DN50, thus covering the range of applications in the chemical and petrochemical industries, the pharmaceutical and cosmetics industries, and - as described - the food and beverage industry.
The heating hose concept is also designed for potentially explosive atmospheres. The focus of such applications: Point overheating and uneven heat distribution with direct reference to ignition temperatures and energies of explosive atmospheres. It is precisely here that the new concept of the heated hose system demonstrates its strengths and a mature design that has been proven in many tests at independent institutes in practical test series.
Trade fairs
Masterflex AG will be presenting templine heated hoses along with numerous other hoses and connection systems at the following trade fairs:
POWTECH Hall 9, Booth 516
FAKUMA Hall A2, Booth 2404
Visit us and make a non-binding appointment with our trade fair team!
We will be happy to send you free admission tickets if required. Please contact us for this purpose.