Rubber Seals Research Articles

Uptake and Release of Aroma Compounds by an Ethylene Propylene Diene Monomer Rubber Sealing Polymer: Investigating Aroma Carryover in a Model Wine System.

Aromatized wines and regular table wines are often filled on the same bottling line. Sealing polymers in the filling line absorb volatiles from aromatized wines and may migrate due to insufficient cleaning into the subsequently bottled regular wine. Unintentional carryover of volatiles may lead to accusation of illegal aromatization of wine. Absorption, cleaning efficacy, and migration of volatiles into ethylene propylene diene monomer rubber were investigated in a model system. Direct thermal desorption-gas chromatography-mass spectrometry analysis of seven aroma compounds monitored variation in the polymer (μg/g). Absorption of volatiles was mostly driven by their octanol/water partition coefficients. Cleaning of polymers removed 11 to 62% of the absorbed volatiles. Subsequent immersion of cleaned polymers into model wine revealed migration of 20 to 57% of the remaining volatiles. Sensory tests suggested the impact of transferred volatiles into subsequent model wine. For α-ionone, an odor activity value of 1.03 indicated a potential sensory impact.

Experimental Study on the Effect of Hardness on the Erosion Resistance of Coatings and Rubber for Hydropower Applications

Abstract Polymeric coatings are used to protect concrete hydropower structures from damage by particle-laden, fast-moving water. In this research, a new experimental method is proposed to simulate this tribosystem. Test materials are submerged in an agitated vessel containing basalt particles and abraded for a fixed time. This paper describes the use of this test to screen polyurea coatings of various types of hardness. The use of such test on rubbers is also described. Results present that the wear process of the polyurea is stable and the wear loss is linear with the erosion time. When the hardness of the polyurea or seal rubber increases, the erosion resistance indicates a downward trend and the surface becomes smooth from rough. A polyurea hardness of Shore D30 and a seal rubber hardness of Shore A70 produce the best slurry erosion resistance. The erosion resistance of the polyurea is much better than that of the high-performance concrete. If the wear thickness is regarded as the evaluation indicator, then the erosion resistance of the polyurea of Shore D30 is approximately 60 times more than that of the high-performance concrete.

Fretting Wear of Rubber Sealing Ring Caused by Fluid Pressure Fluctuation

In the process of gas charging and discharging of gas cylinder, the fluid pressure fluctuates causing fretting wear of rubber sealing ring, which affects the sealing performance. The model of O-ring that installed at the mouth of the gas cylinder was established to study the fretting wear in the static seal. Effects of fluid pressure, compression ratio, friction coefficient and temperature on the fretting wear of the O-ring were considered. The results show that the fretting wear of O-ring can be divided into non-contact region, slip region and sticky region. In the static seal, the compression ratio and friction coefficient are the main factors affecting the fretting wear. The sealing performance is greatly influenced on the compression ratio and it is less affected by the temperature. The junction of slip region and sticky region has the greatest probability of seal failure.

Study on sealing performance of packer rubber based on stress relaxation experiment

In the last few decades, rubber seal elements have been extensively used in the oil and gas industry. However, mechanical properties of rubber decrease at high temperatures, and stress relaxation can lead to sealing performance degradation, even sealing element failure. Therefore, how high temperature and stress relaxation affect the sealing performance of rubber is an important issue in oil and gas production. According to the oilfield feedback information, hydrogenated nitrile butadiene rubber (HNBR) was chosen for sample tension test at different temperature (20 °C and 120 °C) and the stress relaxation tests at 120 °C. The constitutive model of rubber was fitted by the test data. At the setting pressure of 14 MPa, the influence of temperature and stress relaxation on the packer rubber seal system was investigated by finite element analysis (FEA) software. The results indicated that temperature and stress relaxation had an appreciable impact on the sealing performance of packer rubber seal system. The average contact stress at 120 °C between the rubber and the borehole wall, compared with the calculation results at 20 °C, decreased by more than 15% and the maximum contact stress decreased by 20%. Similarly, the average contact stress before the relaxation decreased by more than 35% after stress relaxation behavior at 120 °C. In addition, the maximum contact stress decreased by 50% due to the stress relaxation. Our experimental results and discussion enable us to provide some advice to improve the sealing performance of a packer seal system, and present a basic experimental and theoretical foundation for future research into the optimum design of a packer sealing system.

Effect of vulcanization on the tribological behavior and sealing performance of EPDM seals: Experimentation and simulation

Vulcanization has an important influence on the performance of rubber seals. Modeling is an effective means of determining the optimal vulcanization process parameters. In the present study, the tribological and mechanical properties of ethylene-propylene-diene monomer (EPDM) samples with various degrees of vulcanization were analyzed, and a mathematical relationship between the degree of vulcanization and the properties was established. On the basis of the transient thermo-chemical coupling model of the vulcanization process, a finite element model was developed to solve the problems associated with the process parameters and product properties of rubber seals. The model can be used to evaluate the variation in sealing capacity and service life of seals produced under various vulcanization conditions to determine the optimal vulcanization parameters.

Investigation into effects of side-window rubber sealer on cabin interi-or noise due to external flow disturbances of vehicle

Electric vehicles' rapid commercialization increases the relative importance of wind noise, especially for cabin interior noise. In this study, systematic numerical methods are developed to assess the wind noise insulation performance of side-window rubber seals in a design stage. First, the simplified automotive cabin model (SACM) is constructed to test the rubber seals' sound insulation performance due to external flow disturbance generated by jet flow. The pressure signals due to the jet flow are measured inside and outside the SACM. The difference between the two signals is used as sound insulation performance criteria, so-called insertion loss (IL). Second, a numerical methodology is developed to predict the IL. The surface pressure field on the side window due to jet flow is predicted by using the high-accurate Lattice Boltzmann Method. The predicted surface pressure fluctuations are applied as input load causing side-window vibration. The interior sound is then computed by using the calculated window vibration as input. The validity of numerical methods is confirmed by comparing the predicted results with the measured ones. Finally, the present methods' ability as a design tool is confirmed by comparing the IL of the pad-added rubber seal with that of the regular seal.

Transitions of Wear Characteristics for Rubber/Steel Seal Pairs During the Abrasive Wear Process

Abrasive wear resulting from the microclastic rock is a common failure phenomenon in the drilling environment that often limits the sealing ability and the service life of seals. In this study, the friction and wear process of fluoro rubber (FKM) seals against 304 stainless steel (SS304) after one single entry of SiO2 abrasives were investigated. The influence of the changes in particle state on friction coefficient evolution, wear loss evolution, wear morphologies, and wear mechanisms were discussed in detail. The results indicate that the presence of abrasive particles dispersed between the sealing interfaces clearly improves the friction performance of the seal pairs and deteriorates the wear performance of the metal counterpart. The movement and breakage of particles after one single entering into the sealing interface were obtained. And on this basis, the stable wear process can be divided into three stages. In addition, the main causes contributed to this change of wear mechanisms are the random movement and process of continuous breakdown of abrasive particles. Furthermore, the transition of the wear mechanism that clearly describes the wearing behavior of the seal pairs under these abrasive wear conditions was identified. The results of this study enhanced our understanding of the abrasive wear degradation of rubber seal in practical drilling applications.

Effect of Thermal Degradation of FKM on Three-Body Abrasion under Dry Sliding: Severe Damage Led by the Particle Detention.

Both the high temperature and particle environment at the downhole greatly aggravate the abrasive wear and shorten the service life of the fluororubber (FKM) seal seriously in drilling engineering. At present, there is less awareness of the tribological behavior of seals in such complex working conditions. In this work, the abrasive wear performance of the thermally degraded FKM seal was tested in the form of simulating the intrusion of abrasive particles into the interface. Results show that the wear of both rubber seals and metal counterparts is exacerbated. Through the analysis of the wear scar morphology and friction coefficient, it is revealed that more abrasive caves scatter on the surface due to the mechanical degradation of the FKM. These abrasion caves reduce the tendency of particles to escape from the caves and prolong the abrasive action. Furthermore, the abrasion cave alters the particle motion from sliding to rolling, which leads to more caves generated on the surface of the hard tribo-pair. These results enhance the understanding of the abrasive wear for FKM seals and hopefully contribute to the promotion of seals used in hot abrasive particle environments.

An Investigation in Wear and Friction of Oil Seal for Rubbing by Flame-Sprayed Alloy and Ceramic on Lower Carbon Steel

In this paper, the effect of sprayed coating on the surface of carbon steel on friction and abrasion properties of oil seals which are rubbed by various anti-wear coating materials on is investigated experimentally, and compared with the uncoated AISI 52100 bearing steel. We used the block vs ring tester to explore the friction coefficient of hard surface friction of 5 commonly used rubber seal to 4 different coating layers of bearing steel under oil/no oil conditions. Four coating materials are used, which are Ni-Cr-B-Si alloy, Ni-Cr-WC alloy, ceramics, and ceramics. Five varieties of the oil seal material named HNBR, NBR, FKM, ACM, and SIL are subjected to wear tests for the measurements of friction and abrasion. The experimental results show that HNBR has better wear resistance and less friction, ceramics have higher friction and wear resistance than other coatings due to higher hardness. In terms of oil seal and sprayed coating, Ni-Cr-B-Si alloy and ceramic powder are more suitable for surface wear resistance, because of its hardness and wear resistance and the degree of damage to the oil seal are more excellent. Generally, the greater the wear resistance of the oil seal material, the greater its friction with the coating.

Dishwashers as an Extreme Environment of Potentially Pathogenic Yeast Species.

The study aimed to compare the yeast species diversity in the specific environment of dishwashers, taking into account the potential risk for users. Yeasts were isolated from ten dishwashers and from tap water supplied to the appliances. Samples were collected for mycological analyses at the beginning of each month, from February to May 2016. Four dishwasher sites (rubber seals, detergent dispensers, sprinklers, and water drains) were analyzed. The microfungi were identified by the standard procedures applied in mycological diagnostics. To confirm species identification, molecular analysis was performed based on the sequences of the D1/D2 region. The presence of microfungi was detected in 70% of the investigated appliances. Rubber seals, detergent dispensers, and water drains were the most frequently colonized elements. Thirty-five yeast strains were isolated in this study, of which twenty-seven were obtained from dishwashers and eight from tap water. The strains belonged to six genera and six species (Candida parapsilosis, Clavispora lusitaniae, Dipodascus capitatus, Exophiala dermatitidis, Meyerozyma guilliermondii, and Rhodotorula mucilaginosa). Most of the strains came from rubber seals. In this way, it was demonstrated that the dishwashers’ condition is sufficient as an ecological niche for microfungi.

Evaluation of Key Performance of Aircraft Fabric Rubber Seal During Flight

In this Paper, the mechanic properties and sealing performance of the aircraft fabric rubber seal during flight are studied. First, the mechanic parameters, geometric structure, loading method of different aircraft cabin door fabric rubber seals, and gas conditions are analyzed. Second, the modified gas leakage rate formula of fabric rubber seal within wide ranges of temperature and gas pressure is derived based on the previous gas leakage rate formula of fabric rubber seal and the gas leakage rate experimental results. Then, the gas leakage rate prediction method of multicontact sealing surfaces is established. Finally, the variation law of the aircraft gas leakage rate with the altitude are determined based on the configuration number of the aircraft fuselage doors and the finite element results of the aircraft door seals. The research results will provide reliable scientific guidance for the mechanical performance evaluation and sealing performance prediction of fabric rubber seals.

Influence of normal force in metallic sealing

AbstractMetallic ball seat valves are an essential component in almost every hydraulic system in the form of check valves. Despite their wide usage in real‐life applications, the physical sealing mechanism is not yet fully understood and still debated. One promising method is the contact mechanics theory which has been developed by Persson et al. for rubber seals. It can predict the leakage of rubber seals successfully, but its application for metallic seals, where plastic deformation plays an import role, has only been developed recently and is not yet fully validated. This theory is combined with surface scans of investigated seats and simulations that are performed using the finite element method (FEM) for different geometric configurations. This combination allows an efficient calculation of the leakage of ball seat valves depending on their specific design and applied forces and pressures. In this work, the predictions by simulations according to Persson's theory are compared with experimental results. This comparison is done by analyzing the dependency of the leakage of ball seat valves in relation to applied normal forces and for different surfaces in contact. This validates the applicability of Persson's method in this field. The presented experimental method allows the measurement of the leakage of ball seat valves under realistic conditions.

An Experimental Study on High-Pressure Hydrogen Compatibility of Rubber Seals at FCV Refuelling Receptacles

A method is proposed to test the sensitivity of high-pressure hydrogen compatibility of rubber O-ring seals at FCV refuelling receptacles based on a long-term high-pressure pure hydrogen full-immersion environment testing, in combination with such Chinese standards as the determination of the effect of liquids of rubber and FCV refuelling receptables. Through an aging property test system, the high-pressure pure hydrogen full-immersion testing is conducted for 5 groups of rubber O-ring seals to be measured. Before and after the testing, an electronic balance is used to measure the mass of the rubber O-ring seals, obtaining changes in mass and volume. At last, on the basis of the changes, the sensitivity of the seals of various models and in diverse experimental groups to the high-pressure hydrogen compatibility is obtained through our analysis.

Similarity Calculation Method for Infield and Outfield Low-Temperature Environmental Tests of Aircraft Sealing Rubber Material

This study aims to accurately simulate the outfield low-temperature environment for the key components of aircraft in the parking state, using the infield low-temperature environmental test chamber, when there is a difference between the infield and outfield environments; and, moreover, reveal the similarity between the influences of the infield and outfield low-temperature environments on the elastic properties of the rubber sealing materials for aircraft. Two kinds of rubber materials were examined in the infield and outfield—the tensile springback test and the isobaric elongation test—and the measured data of low-temperature steady-state response (elastic property) were obtained under the typical temperature of −40 to 10 °C, finding that there is difference of elastic property between the infield and outfield environment. Three fitting methods were then used to describe the relationship between elasticity and temperature. In view of the difference of the elastic response of the typical rubber sealing materials to the low-temperature infield and outfield, a similarity calculation method of infield and outfield low-temperature tests was proposed, based on the translation and scaling transformation of the similarity curve. The outfield test data verify that the method proposed has high goodness of fit, and it is feasible and generalizable in the low-temperature performance testing and research of rubber materials and components.

Integrated conductive rubber composites for contact deformation detection of tubular seals

In this paper, a highly sensitive and stretchable conductive rubber composite is integrated into tubular rubber seals for the detection of contact deformations and sealing states. First, the carbon fiber (CF) and carbon black (CB) filled room temperature vulcanized (RTV) silicone rubber composite is prepared, and the integration of CF/CB/silicone rubber composite and the tubular rubber seal is achieved using an omega-shaped mold. Second, the resistance responses of conductive rubber composites integrated tubular seals with different filler contents under compression are studied, which show good stability and repeatability. Finally, a resistance model relating the relative resistance changes to the compressive strain associated with the strain rate is established to characterize the pressure-sensitive property, which is available to quantitatively detect contact deformations for the tubular seals. This study will present significant guidance in the design and analysis of conductive rubber seals for intelligent and automatic sealing detection.

Automated installation of elastic rubber seals into inner grooves of cylindrical parts

Description of kinematic diagram of device for automated installation of elastic rubber seals into internal grooves of cylindrical parts is presented. The limit modes of operation of individual mechanisms are defi ned, at which reliable installation of the seal is provided.

Device for automated installation of rubber O-rings into the outer grooves of cylindrical parts

The tensile force of an annular rubber seal is substantiated during automated installation into the cut grooves of cylindrical parts without interaction with their surfaces.

Justification of the parameters of the pneumatic cylinder and the spring in the device for pressing cylindrical stepped rubber seals into the holes of the assembled units

The parameters of the pneumatic cylinder are substantiated to ensure reliable pressing of cylindrical stepped rubber bushings into the holes of the assemblies and the springs to return the device elements to their original position.

Substantiation of the pushing force of an annular rubber seal through a tapered bushing with protrusions in devices for their installation into the inner grooves of cylindrical parts

The force of punching the seal through a tapered bushing with protrusions has been substantiated.

Analysis of Low Temperature Compression Characteristics of Rubber Seal Strip of Shelter based on ABAQUS

The extreme low temperature of the alpine region is easy to have a bad effect on the sealing performance of the rubber seal strip of the shelter. In this paper, ABAQUS software is used to simulate and analyse the compression characteristics of the seal strip of the shelter at 23°C and -55°C, the Von Mises stress and the surface contact stress at two different temperatures are obtained. The result shows that the compression performance of rubber seal strip is sensitive to the extreme low temperature, and it is prone to low-temperature failure. The simulation results in this paper can provide an important reference for the subsequent low-temperature environmental test, so as to more comprehensively analyse the low-temperature failure mechanism of the rubber seal strip of the shelter in the alpine region.