In a certain power plant, the instrument pipelines, due to their small diameter, are prone to freezing and blockage in winter. Initially, the plant used electric heating tapes for pipeline heat tracing. However, leaks sometimes occur at the interfaces of valves or transmitters, and the temperature of such pipelines is already high, sometimes reaching up to 500°C. Therefore, ordinary heating tapes or heat tracing cables cannot be used normally on such pipelines. After professional technical personnel conducted on-site technical surveys, it was finally decided to use MI heat tracing cables to solve this problem.
Overview of MI Mineral Insulated Heating Cable:
This cable is composed of metal wire cores (heating elements), tightly surrounded by mineral magnesium oxide (insulation layer), and a metal tube (usually copper, steel, or stainless steel) that has been drawn multiple times. In this case, MI stainless steel sheathed heating cables are selected.
Stainless steel heating cables have the following characteristics:
① Because mineral insulated heating cables are entirely composed of non-combustible inorganic materials, the product is fire-resistant and flame-retardant, and does not produce toxic gases. Due to the reliable metal tube sealing and good grounding, it is especially suitable for various explosion-proof locations.
② The magnesium oxide insulation material remains stable even at high temperatures. Therefore, the maximum operating temperature of the heating cable itself is the highest temperature that the wire cores and metal outer sheath can withstand.
③ The insulation layer of the product, magnesium oxide, is an inorganic substance, and both the wire cores and outer sheath are made of metal, fundamentally solving the aging problem and greatly extending the service life of the cable. Under specified conditions, the service life can reach decades.
④ The product uses a stainless steel outer sheath, which is resistant to oils, solvents, and most acids, providing good chemical stability.
⑤ Good mechanical properties: due to its robust structure, it can withstand twisting, squeezing, bending, pulling, friction, and general rough handling.
⑥ Because the heating method of this cable is a series resistance-type electric heating element, the heating is uniform, and the temperature difference along the entire length is minimal.
⑦ High heating power, generally above 30~360W/m. This cable does not risk freezing like steam heating pipelines when steam supply stops. It can be used by simply turning on the power when needed, without frequent maintenance.
⑧ Low-temperature resistance: it does not become brittle during construction at low temperatures, making it easy for winter construction and maintenance.
