Hose Assembly Research Articles

OS4-7-3 Durability Test and Micro-Damage Formation of Rubber Hose Assembly for Automotive Hydraulic Brake

OS4-7-3 Durability Test and Micro-Damage Formation of Rubber Hose Assembly for Automotive Hydraulic Brake

A reply

Thank you for giving me the opportunity to reply to this letter. The text and photographs show a Datex-Ohmeda Mk5a absorber with attached bag/vent switch. Fitted between the bag/vent switch and the bellows is a tube and filter assembly that seems to be the cause of the problem. All of the Datex-Ohmeda fittings on this equipment are ISO 22-mm standard taper. The Flexible hose assembly described in the letter is made by the USA-based Intertech Company and marketed in the UK by Sims-Portex. Datex-Ohmeda are unable to comment on the designs of a competitor product. Our advice is that the bellows are connected to the absorber/vent-bag switch by an ISO-standard 22-mm flex tubing without a filter.

Method and apparatus for reduction of fluid borne noise in hydraulic systems

Method and apparatus for reduction of fluid borne noise in a hydraulic system are disclosed. The apparatus is an improved isolating hose assembly having first and second volumetrically compliant sections fluidly connected by an inductive flow member. Each of the first and second volumetrically compliant sections may, in addition, include a resistive flow element. The resistive flow elements are used to eliminate resonant conditions in the first and second volumetrically compliant sections at selected frequencies where capacitive behavior thereof would otherwise be compromised.

Requirements on the strength of rubber hose assemblies for high pressure acetylene

According to the German Technical Rules for Acetylene Installations and Calciumcarbide Stores (TRAC), TRAC 204 “Acetylene Pipelines” No. 5.3.7., hose assemblies for high pressure acetylene must be tested for sufficient strength to withstand the decomposition of acetylene at the maximum permitted pressure. Until now, all rubber hose assemblies produced for use in high pressure hydraulic systems have failed this approval test. The same rubber hose assemblies fitted with a spiral inside the hose on its full length have successfully passed this approval test. These rubber hose assemblies could be recommended for type approval by the Federal Institute of Materials Research and Testing (BAM) and have been type approved for use in installations for high pressure acetylene according to Article 10 of the German Acetylene Regulations by the competent approval authority in Germany. In this report we have summarized the experience of BAM resulting from experiments with decomposition of high pressure acetylene in tubes and rubber hose assemblies. On the basis of the results of these investigations appropriate requirements for rubber hose assemblies can be made so that in case of a hazard with a decomposition of high pressure acetylene there will be no failure of any rubber hose assembly within the installation.

Measurement of the longitudinal transmission characteristics of fluid-filled hoses

Flexible hoses used within a hydraulic circuit can reduce the levels of both pressure fluctuations and structural vibration. An important application is in automotive power steering where tubular inserts and restrictors are often used inside a hose to enhance the reduction of pressure ripple. The performance of a hose assembly in the frequency domain is usually specified by an impedance matrix relating pressure and flow ripple at the ends. However, these quantities are coupled to fluctuating axial tension and motion of the hose walls and it is desirable to have a 4 × 4 impedance matrix relating the complex amplitudes of all these quantities. A convenient method of experimentally measuring this matrix is presented. As well as allowing investigation of the main structural and fluid transmission from the hose assembly to the subsequent pipework, the 4 × 4 impedance matrix provides a way of obtaining the dynamic properties of hose walls under realistic conditions for use in further studies.

Airport Installations

A flexible stainless steel hose assembly is of special interest as it has been specifically designed for the transfer of liquid gases from mobile ground tankers to aircraft storage tanks.