Rigid- and flexible vacuum insulated transfer line
Vacuum Insulated Piping forms the basis of almost every cryogenic infrastructure. The double-walled pipes ensure that cold liquid gases can be safely transported without excessive warming and lose their liquid state, which causes a quality reduction. Transfer lines connect, for example, a vessel to an application or an ASU (Air Separation Unit) and a transportation vehicle.
To ensure optimal insulation, Demaco supplies vacuum insulated pipes with a multi-layered radiation shield. As can be read on our page about vacuum technology, the combination of a vacuum environment and a radiation shield ensures that various heat loss forms are almost entirely prevented.
1. Rigid vacuum insulated transfer pipes
The most common transfer pipe is the rigid type; we supply these in the form of prefabricated pipe sections. These pipe sections (or spools) cannot be bent and must be precisely measured before manufacturing. If they are a fraction too short or too long, they will not fit into the designed system.
The image above shows how our rigid vacuum insulated transfer pipes are constructed.
As can be seen, the pipes have an inner pipe and an outer pipe. Via the pump valve located underneath the black cap, the space between the two pipes is vacuumized, while the green spacers are used to ensure that both pipes do not touch each other.
Because the inner pipe gets a lot colder than the outer one, it shrinks several millimeters per meter when in use. To prevent impermissible material stress, a compensator is mounted between the two spacers, as shown in the picture. This flexible component absorbs the stress caused by the shrinkage of the inner pipe.
Because of the minimal loss of pressure, high stability, high quality, low cost, and aesthetic appeal, many of our customers choose rigid piping.
2. Flexible vacuum insulated transfer pipes
For projects which require more flexibility, we also offer flexible vacuum insulated transfer pipes. This type of piping provides a slightly lower insulation value than rigid piping, but it has significant advantages when:
- A temporary structure is built (e.g., a test rig)
- Piping routes cannot be precisely measured due to existing obstructions or the lack of an interface during the measurement
- The pipeline is connected to a movable or vibrating application
- Regular coupling and uncoupling is required (for example, at a filling station)
The flexible pipe is constructed in the same way as the rigid type, but due to the flexible shape, it has a slightly larger diameter compared to a rigid pipe with the same throughput. Also, the surface structure is different, which leads to a slightly higher pressure loss.
In our factory, we produce the pipe sections that are then joined together on site. These sections can be up to 12 meters long and are available in various diameters. Often the pipes have a relatively small diameter of DN15/25 or 1 inch, but for large-scale usage, this can go up to 10 inches or more.
Our pipelines are suitable for standard design pressures up to PN40 and are used for applications such as: LN2, CO2, LO2, LAr, LNG, LH2, and LHe.
With our knowledge and technology, we can also accommodate higher pressures, non-standard gases, and larger diameters. Please contact us via our contact page.
As indicated earlier, the structure of our flexible transfer pipes’ surface differs from that of the rigid type. In addition, our flexible pipes often have a slightly larger outside diameter.
Applications of vacuum insulated transfer pipes
High-quality piping ensures that cold liquid gases can be transported safely with the lowest possible energy loss. This is essential in all the industries we serve. For example, in the food industry and the automotive industry, for the supply of liquid nitrogen and in the marine industry for the supply of LNG or hydrogen, and in the air separation industry for the transfer of liquid gas into temporary storage and transportation.
Demaco’s piping is constructed from standardized modules, which are compiled in a product configurator to perfectly match the customer’s needs for a specific project. As a result, the range of applications of our piping systems is enormous.
For more information on the industries we serve with our cryogenic products, check out our industries page.
Because our pipes are delivered in individual sections, they are coupled together on-site using special couplings.
We offer our customers two different types of couplings:
1. Johnston coupling
The Johnston coupling offers more flexibility than welded couplings. The Johnston coupling features a male and a female connector, which can be easily connected and secured. No welding or special knowledge is required.
The Johnston coupling permits a bit more heat inflow than the welded coupling but has the advantage of the ease of installation, removal, or relocation. This even allows the customer to install the pipe modules themselves if necessary.
Want to know more? View the Johnston coupling product sheet for more information on this coupling, including photos and specifications.
2. Welded coupling
Welded couplings form a permanent connection between two pieces of pipe. A solid welded coupling ensures maximum safety and offers the best protection against incoming heat. Two types of insulation can be chosen for a welded coupling: vacuum or perlite. Installing a welded coupling requires specialized equipment, knowledge, and experience.
Care to know more? View the Welded Coupling product sheet for more information on this coupling, including photos and specifications.