Polygon Co. has announced their new pneumatic cylinder known as Constrained Tube Technology (CTT). CTT is a complete pneumatic system that allows the composite tube to be fitted within the confines of a thin-walled outer host. The composite tube carries greater than 90% of the pressure vessel loads while the metallic host enables traditional assembly techniques such as welding, threading, retention rings, etc.
A housing must be used to handle the additional pressure load for the complete tube assembly.
“Housings can be 80/20 aluminum or other machined metal. It could be any material, even a wooden box,” said Paul Lashbrook, lead CTT engineer.
Containing housings do not need to be cylindrical nor do they need to be honed or plated, and can even be a lowgrade steel.
“The housing provides a durable casing for CTT, supporting and protecting the lightweight cylinder,” Lashbook said.
The CTT cylinder is an entire thin-walled actuator system utilizing a new end cap attachment system. The approach enables the design engineer to achieve the benefits of composite cylinder tubing such as corrosion resistance, improved seal life and unique fluid flow properties without manufacturing assembly changes.
For non-housed units, lower cost polymeric cylinders can provide the needed structure. “In traditional cylinders, the metal walls provide both pressure containment and structural strength. With CTT, the inner composite sleeve does all the load work while the thermoplastic outer tube and connection elements provide seamless and cost-effective assembly,” said James Shobert, Polygon Co. CEO. End caps can be fitted to secure the host tube and provide a very traditional cylinder outline for non-housed units as illustrated. This blends the high performance characteristics of advanced composites with the durability and economics of standard polymeric materials.
One consistent Achilles Heel of retrofitting composites into existing applications is being able to assemble the finished product using traditional metalworking techniques. Composite cylinder tubing cannot withstand drilling and maintain structural strength. This limited previous composite tubing to tie-rod cylinder applications almost exclusively. CTT’s tubing is not immune to this attachment problem. However, the required housings can be chosen to provide ample attachment points for mounting the assembly.
CTT has surpassed 27 million cycles under elevated testing pressure and is the perfect solution to demanding pressure vessel applications. Balancing performance and cost, it is uniquely suited for today’s lean operational environments.
Filed Under: Factory automation, Packaging, Fluid power, Linear motion • slides, Pneumatic equipment + components
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