Design of New Cryogenic Vacuum Insulated Flexible Hose Part Two

Joint design

The heat loss of cryogenic multilayer insulated pipe is mainly lost through the joint. The design of cryogenic joint tries to pursue low heat leakage and reliable sealing performance. Cryogenic joint is divided into convex joint and concave joint, there is a double sealing structure design, each seal has a sealing gasket of PTFE material, so the insulation is better, at the same time using flange form installation is more convenient. FIG. 2 is the design drawing of the spigot seal structure. In the tightening process, the gasket at the first seal of the flange bolt deforms to achieve the sealing effect. For the second seal of the flange, there is a certain gap between the convex joint and the concave joint, and the gap is thin and long, so that the cryogenic liquid entering the gap is vaporized, forming an air resistance to prevent the cryogenic liquid from leaking through, and the sealing pad does not contact with the cryogenic liquid, which has high reliability and effectively controls the heat leakage of the joint.

Internal network and external network structure

H ring stamping bellows are selected for the tube billet of internal and external network bodies. H-type corrugated flexible body has continuous annular waveform, good softness, stress is not easy to produce torsional stress, suitable for sports places with high life requirements.

The outer layer of the ring stamping bellows is equipped with a stainless steel protective mesh sleeve. Mesh sleeve is made of metal wire or metal belt in a certain order of textile metal mesh. In addition to strengthening the bearing capacity of the hose, the mesh sleeve can also protect the corrugated hose. With the increase of the number of sheath layers and the degree of covering bellows, the bearing capacity and anti-external action ability of the metal hose increase, but the increase of the number of sheath layers and the degree of covering will affect the flexibility of the hose. After comprehensive consideration, a layer of net sleeve is selected for the inner and outer net body of the cryogenic hose. The supporting materials between the internal and external network bodies are made of polytetrafluoroethylene with good adiabatic performance.


This paper summarizes the design method of a new low-temperature vacuum hose which can adapt to the position change of the docking and shedding motion of the low-temperature filling connector. This method has been applied to the design and processing of a certain cryogenic propellant conveying system DN50 ~ DN150 series cryogenic vacuum hose, and some technical achievements have been achieved. This series of cryogenic vacuum hose has passed the test of actual working conditions. During the real low-temperature propellant medium test, the outer surface and joint of the low-temperature vacuum hose have no frosting or sweating phenomenon, and the thermal insulation is good, which meets the technical requirements, which verifies the correctness of the design method and has certain reference value for the design of similar pipeline equipment.

HL Cryogenic Equipment

HL Cryogenic Equipment which was founded in 1992 is a brand affiliated to HL Cryogenic Equipment Company Cryogenic Equipment Co.,Ltd. HL Cryogenic Equipment is committed to the design and manufacture of the High Vacuum Insulated Cryogenic Piping System and related Support Equipment to meet the various needs of customers. The Vacuum Insulated Pipe and Flexible Hose are constructed in a high vacuum and multi-layer multi-screen special insulated materials, and passes through a series of extremely strict technical treatments and high vacuum treatment, which is used for transferring of liquid oxygen, liquid nitrogen, liquid argon, liquid hydrogen, liquid helium, liquefied ethylene gas LEG and liquefied nature gas LNG.

The product series of Vacuum Jacketed Pipe, Vacuum Jacketed Hose, Vacuum Jacketed Valve, and Phase Separator in HL Cryogenic Equipment Company, which passed through a series of extremely strict technical treatments, are used for transferring of liquid oxygen, liquid nitrogen, liquid argon, liquid hydrogen, liquid helium, LEG and LNG, and these products are serviced for cryogenic equipment (e.g. cryogenic tanks, dewars and coldboxes etc.) in industries of air separation, gases, aviation, electronics, superconductor, chips, automation assembly, food & beverage, pharmacy, hospital, biobank, rubber, new material manufacturing chemical engineering, iron & steel, and scientific research etc.

Post time: May-12-2023