Cryogenic solutionsCryogenic substances are colder than -90°C. Cryogenic flows are handled in the same way as other flows, but the components must be designed to withstand extremely low temperatures.
The materials must be cold resistant, for example, austeniticly??? stainless steel. Valves must be fitted with an extension stem, to prevent the stem seal from freezing. Particular cleanness and dryness are also required from all components.
At cryogenic temperatures, martensitic transformation occurs in the crystal structure of stainless steel. The crystal structure of some of the material’s crystals changes permanently. This is important in precision engineering equipment such as valves, since the volume of the material increases slightly. As a consequence, the shape of the sealing surface may change and the valve may spring a leak. The shape change, however, can be controlled. Good cryogenic valves are cold-treated prior to machining.
Cold process conditions require quality from valves
At extremely low operating temperatures, the manufacturing quality becomes even more important. Equipment in the design of which the specific requirements of cryogenics have been considered and in the manufacture of which a high quality level has been achieved must be preferred.
The larger is the temperature difference between the media and the environment, the greater is the importance of thermal energy flow control. IAn increase in the temperature difference leads to more intensive loss of heat. Major temperature differences also hold considerable potential for the utiliszation thereof. One way for the minimisation of heat transfer between the pipe and the ambient environment is the use of double casing pipes. Mechanical energy generated by gasification can be recovered using microturbines, for example.
Valves for LNG are also available
Liquefied natural gas (LNG) is a cryogenic fuel. Its gasification temperature is -163°C. The energy density of LNG is high, which means that it can be transferred efficiently. In order to be used as fuel, however, LNG needs to be gasified, which can take place at a plant designed for this purpose or directly on-site. We also offer equipment for other cryogenic media.
Our cryogenic products range includes a wide choice of shut-off, control, and safety valves, measuring equipment, heat exchangers, and equipment for the control of energy flows.