Piping design
Pipes – the big picture: from engineering design and production to corrosion protection

Pipes can transport all kinds of gas, fluids, granulate, paste and sludge. When engineers design in corrosion protection, they have to consider the process conditions (pressure, temperature and flow rate) as well as the properties of the medium. PROCESS worldwide asked some specialists in corrosion-resistant technology about planning quality, new materials and monitoring systems.

Butting believes that installation of a complex network of pipes could account for up to 50 percent of total installation time at a process industry plant. Because the pipe system design and installation phases are so important, the company uses powerful engineering tools to support these tasks (ITandFactory’s 2D and 3D Tricad CAD-System). This approach enhances planning quality, speeds up project completion and reduces the cost. Detailed isometric drawings can help to optimize logistics especially during the installation phase. Reliable CAD documentation is also essential for pre-fabrication of pipes and containers (“factory-based installation”). In one practical example, 108 cooling coils made of grade 1.4571 material needed to be produced. Ready-to-install 40-meter coils were made using 4,500 meters of high-grade 114.3 x 2 mm tube. By using state-of-the-art CNC bending technology, Butting was able to replace most of the circumferential welds with bends. This reduced welding costs by more than 80 percent.

Ceramic wear protection
If you plan carefully and use pre-fabricated parts, then you have already done quite a lot to reduce excessive wear. It remains a problem that no one can accurately predict whether and to what extent a particular pipe material is compatible with a given medium. The experts at Scholten say that a high-wear part should never be viewed in isolation. Instead, you have to look at the entire wear system (all of the stress factors). In order to identify an effective methods of corrosion protection, you have to collect as much information as possible about all of the stresses which are involved. You have to know what base materials and mating materials are used, what the flow rates are expected to be, etc. Practical experience has shown that pipes and ducts wear very quickly in a limited number of places, while the rest of the system shows little wear. Scholten recommends the use of ceramic material combinations (e.g. aluminum oxide or zirconium oxide ceramics) to ensure long service life. Detloff uses sandwich sheets. The A.S.S. sandwich plate has a hard carbide-rich layer which is attached to a steel substrate using a special welding process. The high carbide content (mainly chromium carbides as well as special carbides and borides) produces good wear characteristics. The welding process can be modified to suit the particular requirements (the alloy materials are fed directly to the arc in powder form).
The coatings are a minimum of three millimeters thick and can be as much as ten millimeters or more. The email 250 light series of pipes from Jacob Rohrsysteme have an acid-proof enamel coating which gives them good chemical resistance. They are also anti-adhesive and are able to withstand high thermal stress. The manufacturer also cites long service life as another advantage of this product line. CEO Ralf W. Borcherding believes that the products are ideal for the chemical, pharmaceutical and plastics industries and any applications where chemical waster water, aggressive air, welding fumes, ethanoic acids, grease, etc. have to be removed from the production process. “This new enameled light-weight pipe will cause a sensation in the market, because an enameled, thin-wall system for exhaust gas and waster water applications has not been available in the past. Most systems on the market today have thick walls, making them significantly heavier, and they are lined with plastic or glass. As fire regulations become more stringent in the international marketplace, plastic versions are becoming increasingly obsolete.”
Special tubing for high continuous loads
Norres PUR 335 special tubing, which is made of high-grade premium ether polyurethane (Pre-PUR), is available in diameters between 80 mm and 600 mm. The manufacturer claims that the tubing is ideal for material transport systems, vibration machines and tumbler screening machines due to its excellent wear and vibration characteristics. The interior of the tubing is smooth and has optimal flow characteristics, and it is a good choice when users need tubing to transport media in the –40°C to +100 °C-range. The tubing
-is microbe and hydrolysis resistant
-contains no plasticizers or halogens
-is impermeable to gas and fluids
-is immune to the effects of oil, gasoline, chemicals, UV radiation and ozone
-can be supplied in transparent or colored and printed versions.
Because it is very resistant to tensile and shearing forces, it can also be used as a bellows or an expansion joint. The 335-MHF version is designed for use in the food and pharmaceutical industries.
Protect your workers and the environment
When you convey substances that are toxic or pose an environmental hazard, you have to avoid leaks at all costs. Kalenborn offers electrical, mechanical and pneumatic monitoring systems to help you keep things under control. Electrical wear monitors use a low-voltage electrical lead which is mounted on the outside of an anti-wear lining. If the protection coating inside the pipe is worn through at any point, the lead is severed. An appropriately designed control system can identify the damaged section of pipe, and the system can be shut down automatically.
Pneumatic monitoring systems use double-walled steel. An alarm is issued or the system shuts down when the pressure falls in the space between the walls. Mechanical monitoring is the easiest method of keeping an eye on wear. A probe is screwed into a hole which is drilled into the outer pipe and the anti-wear lining.