Rockwood have built up a significant expertise in the use of composite materials for cryogenic applications, ranging from suspension system components of struts and tension bands, through to high voltage insulation systems with embedded thermal conductors and polymer films. These elements are often brought together by combining normal composite processing techniques and some techniques which are cryogenic specific
Cryogenics and fusion reactor components
We manufacture glass and carbon fibre bands and struts used to support cryogenically components such at magnets and thermal shields. We have manufactured bands from 1.5 tonnes in glass fibre through to 50 tonne in carbon fibre. We understand the design optimisation process taking into account fatigue and thermal loading conditions.
We supply complete suspension solutions which includes non-magnetic interface hardware (yokes, flexible joints, spools etc.) and have our own unique and patented termination that provides one of the most cost effective termination methods available.
Our glass and carbon bands are manufactured using pre-preg materials, which means very tight control of material properties and a very high build rate. This results in ultimate performance delivered at the lowest possible cost.
In addition to our band we also produce struts which are suspension structures which react tension and compression load in one element, enabling one strut to replace two tension bands to save space.
Rockwood have developed a number of specialist electrical insulation systems operating at cryogenic temperatures many of which incorporate multilayer polyimide (Kapton®) and thermal conductors. Based on glass fibre pre-preg technology, insulation has been applied to busbars and magnet coil conductors, magnet cores and metal backed PCBs.
Pre-preg insulation systems provide many advantages over the traditional vacuum pressure impregnation (VPI) insulation. These include better placement accuracy in complex structures, thinner insulation, tight control of fibre/resin ratio leading to greater shear strength and accurate insulation thickness there are no resin rich areas.
Bonding composite and metallic parts together is an important part of our work. This is covered in three different ways depending on the application. Structural bonding using film or paste adhesive is the first method and usual associated with suitable pre-treatment operations. The second area is high accuracy bonding, where we use a dry carrier fabric is used to control the bond line thickness. The adhesive is dispensed in such a manner that it does not influence the bond line thickness. Lastly we use pre-preg bonding when assembling between multi-element insulation systems. This is used for PCB type structures where multiple layers of aluminium and Kapton® and to be bonded together. This is also used where insulation like Kapton is applied directly to coil windings, conductors or busbars.
These include insulator trays with embedded thermal pathways and high mechanical load bearing pads with insulating properties.
Switch and coil support structures
We manufacture switch components gradient coils through to small shim switches
Design and Analysis
The starting point for any band design is the ultimate strength requirement, the thermal conductivity and the physical installation. We provide customers with design support of the structural members and the interface hardware.
Rockwood Engineering Testing and Evaluation
The key to good product performance is good engineering design, correct choice of materials and processes plus a controlled and skilled production environment. We complement this approach with product testing both at room and cryogenic temperatures.
Pictures curtesy of Composites Test and Evaluation Ltd and Westmoreland Mechanical Testing & Research Ltd
High Voltage Cryogenic Electrical Insulation Systems
Rockwood have been involved with the development of a number of novel glass/polyimide insulation systems that are very stress demanding and have zero void content requirements.
Bonding methods of electrical insulation material to large structural components have been developed to provide exceptional bond line thickness control.