Abstract: A hose for containing a vacuum, which hose has an impermeable flexible tube capable of holding a vacuum and a braided or interwoven flexible interior wall, said wall providing support to said interior wall of said impermeable flexible tube. Optionally, an exterior braided or woven wall may be provided to the hose for protection or to allow the hose to be used as a pressure hose. The hose may delimit a vacuum space through which may travel a thermal transfer line containing, for example, cryogenic fluid.

Abstract: A connecting joint for a radio frequency waveguide line comprises a tubular metallic braid wire shield connecting two beam line pipe ends thereby making the inside surface appear as a continuous beam tube. The metallic braid wire is secured within a bellows assembly that allows the connecting joint to expand or contract as is appropriate for changes in ambient conditions or conditions within the waveguide line. The connecting joint is capable of supporting either positive or negative pressure within the joint while the exterior of the joint may vary with ambient conditions.

Abstract: A muffler for silencing low frequency noise of gas inducting machinery. The muffler includes a buffer reservoir having an inlet and an outlet. The outlet communicates with the gas inlet of the machine. The buffer reservoir has a volume of between twenty and thirty times the displacement of the largest equivalent cylinder of the gas inducting machinery. For a single piston compressor this would be a volume of ten to fifteen times the effective cylinder displacement of the compressor. A convergent/divergent nozzle is connected to the reservoir inlet. The nozzle throat is specially dimensioned relative to the machinery to pass the gas through it to the gas inlet at a throat velocity in the range of Mach 0.7 to 1. A suitable preswirler may be connected to the inlet of the nozzle to reduce the pressure drop across the nozzle.