PTFE sheet sealing material introduced

1995 ◽  
Vol 1995 (19) ◽  
pp. 4-5
Keyword(s):  
Sealing Material ◽  
Ptfe Sheet

Review of Mechanical and Sealing Performance Aspects of Commercially Available PTFE Based Gasket Materials

2018 ◽  
Author(s):  
Dale A. Rice ◽  
A. Fitzgerald Waterland
Keyword(s):  
Room Temperature ◽  
Chemical Resistance ◽  
Bolted Joints ◽  
Leak Rate ◽  
Performance Criteria ◽  
Maximum Temperature ◽  
Fugitive Emissions ◽  
Sealing Material ◽  
Sealing Performance ◽  
Ptfe Sheet

Gaskets incorporating polytetrafluoroethylene (PTFE) are one of the most common in use today where soft sealing material is needed in bolted joints. Over the years, various types of gaskets have been developed including those using skived, expanded, filled, or molded PTFE sheet. Still other PTFE gaskets have been fabricated, incorporating some type of metal insert. Although many of the key benefits (e.g., chemical resistance, application in a broad range of flange types, higher maximum temperature and stress levels than most elastomers, indefinite shelf life, etc.) remain, the performance of the gasket will vary significantly according to the type of PTFE gasket employed. These variations in accordance with PTFE gasket styles are presented and discussed with an emphasis on such criteria as relaxation, gasket tightness / leak rate, and safe reserve operating temperature. For estimating tightness and predicted leak rates, the previously reported “Fugitive Emissions Calculator” (FEC) model has been used which employs Room Temperature Testing (ROTT) data and an ASME / PVRC draft empirical equations set. Published test data have also been compiled to support conclusions concerning relative capabilities for selected PTFE gasket categories. The differences in analytical and leak rate performance criteria have been used to suggest appropriate applications for various subtypes of PTFE gaskets.

Comparative Study of Acid Etching on Dental Enamel

2018 ◽  
Vol 69 (10) ◽  
pp. 2913-2915
Author(s):  
Daniela Jumanca ◽  
Anamaria Matichescu ◽  
Atena Galuscan ◽  
Laura Cristina Rusu ◽  
Cornelia Muntean
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Experimental Study ◽  
Orthophosphoric Acid ◽  
Dental Enamel ◽  
Acid Etching ◽  
Sealing Material ◽  
Mechanical Bond ◽  
Materials Used ◽  
Scanning Electron

This experimental study aims to analyse the effectiveness of various materials used in demineralisation of dental enamel. This work aims to create a mechanical bond by filling the pegs with sealing material. In order to achieve this goal, five teeth were compared using different concentrations of orthophosphoric acid and exposure times. In this regard, five different tests were performed and the results were analysed using the SEM technique (scanning electron microscopy). These comparative analyses revealed that etching using 35% orthophosphoric acid for one minute and etching using Icon Etch for two minutes were the most effective.

scholarly journals Method for designing the optimal sealing depth in methane drainage boreholes to realize efficient drainage

2021 ◽  
Author(s):  
Minghao Yi ◽  
Liang Wang ◽  
Congmeng Hao ◽  
Qingquan Liu ◽  
Zhenyang Wang
Keyword(s):  
Drainage System ◽  
Surrounding Rock ◽  
High Concentration ◽  
Failure Characteristics ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Sealing Material ◽  
Sealing Performance ◽  
Key Factor ◽  
Quantitative Analysis Method

AbstractThe purpose of underground methane drainage technology is to prevent methane disasters and enable the efficient use of coal mine methane (CMM), and the sealing depth is a key factor that affects the performance of underground methane drainage. In this work, the layouts of in-seam and crossing boreholes are considered to analyze the stress distribution and failure characteristics of roadway surrounding rock through a numerical simulation and field stress investigation to determine a reasonable sealing depth. The results show that the depths of the plastic and elastic zones in two experimental coal mines are 16 and 20 m respectively. Borehole sealing minimizes the air leakage through the fractures around the roadway when the sealing material covers the failure and plastic zones, and the field test results for CMM drainage at different sealing depths indicate that the CMM drainage efficiency increases with increasing sealing depth but does not change once the sealing depth exceeds the plastic zone. Moreover, sealing in the high-permeability roadway surrounding rock does not have a strong influence on the borehole sealing performance. Considering these findings, a new CMM drainage system for key sealing in the low-permeability zone was developed that is effective for improving the CMM drainage efficiency and prolonging the high-concentration CMM drainage period. The proposed approach offers a valuable quantitative analysis method for selecting the optimum sealing parameters for underground methane drainage, thereby improving considerably the drainage and utilization rates of CMM.

scholarly journals Evaluation of Antimicrobial Efficacy and Permeability of Various Sealing Materials at the Implant–Abutment Interface—A Pilot In Vitro Study

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 385
Author(s):  
Igor Smojver ◽  
Marko Vuletić ◽  
Dražena Gerbl ◽  
Ana Budimir ◽  
Mato Sušić ◽  
...  
Keyword(s):  
Fungal Infections ◽  
Aerobic Condition ◽  
In Vitro Study ◽  
Vitro Study ◽  
Antimicrobial Efficacy ◽  
Sealing Material ◽  
Implant Abutment ◽  
Static Conditions ◽  
Sealing Materials

The microenvironment of the oral cavity is altered when an implant, a biocompatible foreign body, is inserted into the mouth. Bacteria settle in the tissues in and around the implant due to the passage of microorganisms through the microgap at the connection of the implant and prosthetic abutment. To prevent colonization of the implant by microorganisms, one idea is to use sealing and antimicrobial materials to decontaminate the implant–abutment interface and close the microgap. The purpose of this study is to evaluate the antimicrobial efficacy and permeability of different types of sealing materials at the implant–abutment interface, under static conditions. Three different sealing material (GapSeal gel, Oxysafe gel and Flow.sil) were used for sealing the implant–abutment interfaces in 60 titanium dental implants, which were first contaminated with a solution containing Staphylococcus aureus and Candida albicans for 14 days under an aerobic condition. Results showed that a complete seal against bacterial infection was not formed at the implant–abutment interface, while for fungal infections, only GapSeal material helped to prevent microleakage. Findings of this in vitro study reported that application of sealing material before abutment connection may reduce peri-implant bacterial and fungal population compared with the interface without sealing material.

Use of polyvinyl butyral film wastes for fabrication of adhesive sealing material

2008 ◽  
Vol 40 (1) ◽  
pp. 48-49
Author(s):  
S. E. Artemenko ◽  
L. P. Nikulina ◽  
G. Yu. Gashnikova
Keyword(s):  
Polyvinyl Butyral ◽  
Sealing Material

scholarly journals In vitro Comparison of Apically Extruded Debris during Root Canal Retreatment with Rotary and Reciprocating Systems

2019 ◽  
Vol 13 (1) ◽  
pp. 488-492
Author(s):  
María J. Burbano Balseca ◽  
Silvana B. Terán Ayala ◽  
Fábio D. da Costa Aznar ◽  
Adriana R. de Freitas-Aznar ◽  
Guillermo M. Aguirre Balseca ◽  
...  
Keyword(s):  
Similar Amount ◽  
Hybrid Technique ◽  
Significance Level ◽  
Sealing Material ◽  
Apical Extrusion ◽  
Root Canal Retreatment ◽  
Group A ◽  
Group B ◽  
Reciprocating Systems

Introduction: The extrusion of apical detritus during the retracting procedure is very important, as, besides eliminating materials of radicular obturation, aggressive agents and products such as the remains of dentin taken out, and microorganisms are generally located in tissue around the roots, producing undesired effects, such as inflammation, acute pain, post-operatory pain and delays in the periapical treatment. Objective: To determine the amount of apically extruded detritus using rotary and reciprocating retreatment systems. Methodology: An experimental comparative study as conducted in which 40 single-rooted human first premolars were analyzed. The instruments used were ProTaper Universal files up to F3 and sodium hypochlorite, and the sealing was made through the hybrid technique Tager. They were then kept at 37ºC and 100% of humidity for 15 days so that the sealing material would seal. For the retracting procedure, experimental tubes previously weighted were used. The sample was divided randomly into two groups of 20 pieces. Group A: ProTaper R, and group B: Reciproc. Then, the irrigating material (distilled water) was evaporated from the tubes for 12 hours in a stove at 105ºC, and the experimental tubes were weighted in an analytical precision weighing scale 10-5g. The data was analyzed through the T Student with a significance level of 5%. Results: Results indicated that groups A and B, retreatment with rotational ProTaper R and reciprocating retreatment system (Reciproc) showed a similar difference of initial and final weights, indicating similar apical extrusion of detritus. Conclusion: Both systems extruded a similar amount of detritus during the retreatment procedures.

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