U.S. patent application 20180180221 (applicant Steelhead Composites LLC, Golden, Colo.):
"The present invention provides a lightweight high pressure vessels that are made from a liner or a liner housing that is overwrapped with a composite material. Unlike conventional high pressure vessels, the lightweight high pressure vessel of the invention includes a liner that comprises a plurality of liner sections without using welding or crimping. In particular, the lightweight high pressure vessels of the invention include a plurality of elements that are combined to form a liner housing and a composite overwrap that provides structural and mechanical strength to maintain integrity of the high pressure vessel. In one particular embodiment, the high pressure vessel of the invention is a diaphragm accumulator. ... [In some embodiments] interior of said accumulator comprises a phase changing material."