Trends in the Development of Machinery and Associated Technology ” TMT 2008 , Istanbul , Turkey , 26-30 August , 2008 PERFORMANCE CHARACTERISTICS OF POLYURETHANE FOAM GASKETS
In this study, the performance characteristics of polyurethane foam gaskets have been investigated experimentally in a flanged joint system. Accordingly, it is possible to be compared the test results of polyurethane foam gaskets which have different properties by using this designed testing apparatus. Samples are prepared as foam in place method by using polyurethane material. Whilst samples have been prepared, mixing ratio of 2 different materials, weight in grams value of foamed gasket in 1 second (g/s) and temperature of foamed surface are taken variable parameters; ambient temperature, same type material and polyurethane foam gasket machine foaming velocity are taken constant parameters. The results obtained from the experiment are targeted to use by selecting the optimum gasket according the operating conditions.
A New Concept of Static Rubber Gasket for Sealing Rough Surface
This paper reports on a new concept for static seal designs taking into consideration the surface roughness of sealing surfaces. The concept focuses on fluid penetration from the interstices between the seal and counterface caused by surface roughness. In the study, we investigated the relation between the leakage and surface roughness of the sealing surface of the elastomer seal. At the same time, we also analyzed the contact state of the elastomer seal based on the equations of Ishiwata et al. on deformation of elastomer surface into rough surfaces [1]. The micro-leakage testing machine (SMLA) developed by the authors was used to measure micro-leakage at high precision and in a short time [2]. The results showed that the sealing phenomena were related to the ratio of seal surface contact pressure P s / elastic modulus of seal E, determined by the compression ratio of seals, and does not depend on the chemical structure and hardness of the elastomer used. Furthermore, we reviewed the equations for predicting leakage based on the shape and elastic modulus of the elastomer seal, surface roughness of the seals and counterfaces, and using conditions, and found that these can be simulated.
Observations of nearshore infragravity waves: Seaward and shoreward propagating components
[1] The variation of seaward and shoreward infragravity energy fluxes across the shoaling and surf zones of a gently sloping sandy beach is estimated from field observations and related to forcing by groups of sea and swell, dissipation, and shoreline reflection. Data from collocated pressure and velocity sensors deployed between 1 and 6 m water depth are combined, using the assumption of cross-shore propagation, to decompose the infragravity wave field into shoreward and seaward propagating components. Seaward of the surf zone, shoreward propagating infragravity waves are amplified by nonlinear interactions with groups of sea and swell, and the shoreward infragravity energy flux increases in the onshore direction. In the surf zone, nonlinear phase coupling between infragravity waves and groups of sea and swell decreases, as does the shoreward infragravity energy flux, consistent with the cessation of nonlinear forcing and the increased importance of infragravity wave dissipation. Seaward propagating infragravity waves are not phase coupled to incident wave groups, and their energy levels suggest strong infragravity wave reflection near the shoreline. The cross-shore variation of the seaward energy flux is weaker than that of the shoreward flux, resulting in cross-shore variation of the squared infragravity reflection coefficient (ratio of seaward to shoreward energy flux) between about 0.4 and 1.5.