Rubber Seals Research Articles

Mechanical characteristics and regression models of rice husk silica reinforced natural rubber composites

Carbon black and silica fillers have been widely used as reinforcing fillers in tyres and engine mounts. However, both fillers are non-renewable and with REACH legislation in Europe, the USA and elsewhere, where some of these fillers are termed hazardous due to the presence of polyaromatic hydrocarbons (PAHs), there is a need to search for sustainable alternative fillers to wholly or partially replace carbon black as a filler. This research studied rice husks-derived silica (RHS) as a filler in natural rubber (NR). The characteristics of RHS at 50 phr to 90 phr filler loading levels were examined to determine its suitability as a substitute for unsustainable carbon black (N772) fillers used in the rubber industry. Bound rubber content, crosslink density, tensile strength, young modulus, tear strength, shore A hardness, compressive set, and elongation at break were measured. Regression models were generated and the correlation of determination (R2) values was obtained. The RHS composites resulted in maximum tensile strength of 13.20 MPa at 90 phr, tear strength of 119 MPa at 90 phr, shore A hardness of 69 at 90 phr, compressive set of 6.72% at 80 and 90 phr, elongation at break of 453.60% at 80 phr, bound rubber content of 92.14% at 50 phr and crosslink density of 3.87×10-2 mol/cm3 at 70 phr. The results obtained were within the range of those obtained for the carbon black filled composites across various loading levels. The R2 value of mechanical characteristics for the RHS and N772 samples respectively were 50.06% and 62.18% (bound rubber content), 97.62% and 99.85% (tensile strength), 98.44% and 63.97% (tear strength), 89.16 and 97.40% (Shore A hardness), 32.90% and 91.80% (compressive set), a d 50.91% and 46.91% (elongation at break). Rice husk-derived Silica filled natural rubber composites showed favourable mechanical properties and can substitute traditional fillers in tyres, rubber engine mounts, bushings, seals and doormats.

Vacuum Suction Pad Design and Real-Scale Performance Evaluation of an Automatic Mooring System for the Establishment of a Smart Port in South Korea

A ship’s automatic mooring system relies on vacuum suction pads with rubber seals to withstand external loads, such as mooring forces. This paper focused on the design requirements and performance testing of vacuum suction pads to develop a high-performance automatic mooring system and evaluated the performance of vacuum suction pads through real-scale testing. The mooring capacity of the target ship, the training ship HANBADA, was estimated based on the port and fishing port design standards of the Ministry of Oceans and Fisheries. Under the most extreme ocean conditions (beafort 6), the estimated longitudinal (surge) and lateral (sway) mooring forces acting on HANBADA were 17.7 and 248 kN, respectively. In the real-scale performance test, stable suction was achieved under both dry and water spraying conditions, with the suction force ranging from 180 to 200 kN, under sway conditions. The vacuum ratio remained satisfactory, indicating stable suction. However, under surge conditions, the vacuum ratio decreased slightly to 0.99. Furthermore, the rubber seals returned to their initial shape after load removal, demonstrating their effectiveness in the automatic mooring system. This study provides valuable insights into the design requirements and performance testing of vacuum suction pads, establishing their suitability for developing high-performance automatic mooring systems.

Experimental investigation of three-body wear for rubber seals in abrasive slurry environment

Three-body wear is a complex phenomenon occurring when abrasive particles present between two material surfaces. By developing a new experimental setup, we systematically study wear at the contact between stainless steel and three different rubbers (TPU, NBR and LSR) in a slurry environment, i.e. water containing sand particles. Results showed that wear on both metal and rubber pads increases exponentially with the sliding speed, while a weak correlation was observed with the applied normal load for the given range of load. Wear analysis showed that the stainless steel experienced the most wear when in contact with NBR and the least when in contact with LSR. The TPU rubber pads experienced the most wear, whereas the LSR pads barely exhibit any wear when in contact with the stainless steel. Furthermore, frictional measurements indicated an inverse relationship between the system coefficient of friction and the amount of wear observed on the rubber elements. These observations are discussed in terms of the probability of the sand particles being clung to the rubber pads, after which they abrade the steel surface. This probability is justified as a function of the rubber material properties and the system friction coefficient. The findings in this study suggest new directions for minimizing three-body wear at the contact between metals and rubbers.

Storage of a mixture of natural gas and hydrogen in underground gas reservoirs

In accordance with the document of the Ministry of Industry and Trade – Hydrogen Strategy of the Czech Republic, it can be expected that in the coming years, pressure will be exerted to inject hydrogen into the gas infrastructure, which is currently used mainly for natural gas. Injection of hydrogen into natural gas can have an effect not only on the transport and distribution system, but also on the storage of this mixture in underground reservoirs in CR. This article aims to describe the issue of storing a mixture of hydrogen and natural gas in underground reservoirs. In particular, the effect on the storage capacity and on the overall integrity of the reservoir, problems with the embrittlement of the metal parts of the probes, the effect on the rubber seal. The paper therefore describes not only the effects on the storage of a mixture of hydrogen and natural gas, but also on the devices that are located on surface technologies. The results of studies from foreign literature demonstrate that the addition of 10-15% by volume of hydrogen to natural gas will have a minimal effect on the operation of the underground reservoir. The storage of a mixture of hydrogen and natural gas in the Czech Republic is currently a much-discussed topic, also regarding the experience with the storage of town gas (which contained a high proportion of hydrogen) in the Lobodice aquifer type underground gas storage.

Effect of zinc oxide/layered double hydroxide on friction properties of silicone rubber at low temperature

Effect of zinc oxide/layered double hydroxide on friction properties of silicone rubber at low temperature

Vulcanization and stress analysis of heat vulcanizing bonding joints in fabric rubber seals

Vulcanization has a great impact on the performance of rubber products, which is difficult to analyze due to its complicated process and boundary conditions, especially for complex rubber products like aircraft fabric rubber seals. In this paper, an optimized relationship between reaction order and temperature was first developed based on the comparative study of the existing vulcanization kinetic equations, showing improved accuracy and wider applicable temperature ranges. In the temperature range of 160 °C ∼ 190 °C, the determination coefficient of the model can reach 0.9973. Then, finite element models of pure rubber and fabric rubber were established with Abaqus UMATHT and UMAT subroutines to simulate the vulcanization process and analyze the relationship between the stress in the vulcanization process and the non-uniformity of the vulcanization degree field. Finally, the process of mold core synchronous heating was adopted to reduce the non-uniformity of the vulcanization degree field for the heat vulcanizing bonding joint, so as to reduce the residual stress at the joint. Compared with the traditional upper and lower surface heating mode, the residual stress is reduced by about 20 %. This study provides a theoretical guidance for improving the quality of heat vulcanizing bonding joints of seals.

Research on Aging State Detection Method of Rubber O-ring Sealing Structure

The rubber seal structure is used extensively in mechanical devices, long-term use may bring major safety hazards and economic losses. In order to ensure the healthy operation of machinery and equipment, it is necessary to test the aging condition of the rubber sealing structure nondestructive online. In order to address the problem of unsteady vibration signals, a complex nonstationary signal is degraded into the sum of multiple product functions by means of global local mean decomposition, and then the energy features in these PF components are extracted, and the first three components with the largest energy eigenvalues are selected to form a sensitive feature vector set. Overall, the results of the search data show that the proposed method can efficiently extract energy features from a large set of original features, and the first three largest energy features can be selected to form a sensitive feature set, which can provide effective data information for the detection of the aging state of Rubber O-ring Sealing Structure (ROSS) in the next step.

Study on early seal failure of CO2-injected packer based on orthogonal experimental method

Early seal failure occurs frequently in the of CO2 injection well packer, which is mainly manifested as failure of packer rubber, which seriously affects the normal production of gas well. Aiming at the packer rubber of CO2 injection well, three factors affecting the seal failure of packer rubber were selected, namely temperature, pressure and decompression velocity and the sensitivity of each factor was analyzed by orthogonal experimental design. The results show that the mechanical properties of rubber decrease gradually with the increase of temperature, pressure, and decompression velocity. With the increase of the decompression velocity, the surface of the rubber gradually formed small bubbles, large bubbles and even bubble cracking phenomenon, rubber sealing performance parameters are significantly worse; the main cause of early packer seal failure is the gas injection well was suddenly released, and the gas that could not exude in the rubber in a short time expanded and formed bubbles or even burst under the action of the pressure difference between inside and outside. The optimal decompression velocity is obtained to keep the packer rubber seal well in the downhole corrosion environment, which provides a basis for the determination of the construction parameters of CO2 injection well.

The Particle Breakage Effect on Abrasive Wear Process of Rubber/Steel Seal Pairs under High/Low Pressure.

Pressure has a significant effect on rubber seal performance in the abrasive environments of drilling. The micro-clastic rocks intruding into the seal interface are prone to fracture, which will change the wear process and mechanism, but this process is not yet known at present. To explore this issue, abrasive wear tests were carried out to compare the failure characteristics of the particles and the variation wear process under high/low pressures. The results show that non-round particles are prone to fracture under different pressures, resulting in different damage patterns and wear loss on the rubber surface. A single particle force model was established at the soft rubber-hard metal interface. Three typical breakage types of particles were analyzed, including ground, partially fractured, and crushed. At high load, more particles were crushed, while at low load, shear failure was more likely to occur at the edges of particles. These different particle fracture characteristics not only change the particle size, but also the state of motion and thus the subsequent friction and wear processes. Therefore, the tribological behavior and wear mechanism of abrasive wear are different at high pressure and low pressure. Higher pressure reduces the invasion of the abrasive particles, but also intensifies the tearing and wear of the rubber. However, no significant differences in damage were found for steel counterpart throughout the wear process under high/low load tests. These results are critical to understanding the abrasive wear of rubber seals in drilling engineering.

An Investigation of Latex Sensitivity and Respiratory Complaints in Workers in a Rubber-Based Material Manufacturing Industry.

To present study aimed to investigate the prevalence of latex sensitivity in a workplace that produced rubber-based vehicle seals. The serum latex-specific IgE levels, respiratory complaints, PFT, serum interleukin (IL)-4, IL-5, IL-8, IL-10, IL-13 levels of all male workers (n = 108) exposed to latex in the workplace, which produced rubber seals, were compared with the control group (n = 52). The rates of latex-specific IgE >0.10 kU/L in the workers and control group were 12.3% and 4.1%, respectively ( P = 0.147). There was no difference in IL-4, IL-5, IL-10, and IL-13 levels between latex-specific IgE-positive, and -negative participants. Latex sensitivity was higher in workers who used rubber as a raw material than in the control group but it was not statistically significant.

Study on the aging of three typical rubber materials under high- and low-temperature cyclic environment

Abstract As the key components of sealing applications, rubber seals are subject to complicated environmental conditions during the service lifetime. In this study, the aging of three typical rubber materials, ethylene–propylene–diene monomer rubber, liquid silicone rubber, and fluorine rubber, was tested under different high- and low-temperature cycle aging environments. The experimental results confirm that the reciprocating temperature cycle causes a type of fatigue failure, which could result in an increase in the rubber compression set. In addition, a novel accelerated aging test method was proposed based on the dominant damage mechanism of rubber material caused by the temperature cycle treatments. Based on this method, the long-term aging test results of rubber samples under high- and low-temperature cycle conditions can be predicted. This method could significantly shorten the aging test time and reduce the test cost.

The performance of double-layer rubber sealing ring under the action of low temperature environment

Aiming at the sealing failure of a water quality monitoring system in a low-temperature environment, a double rubber O-ring sealing structure was designed, and its sealing performance at low temperatures was studied. Finite element software ANSYS constructed the sealing structure, and the change of sealing performance of rubber O-ring in the process of standard temperature installation and low temperature was studied by a two-dimensional axisymmetric model. The results show that the equivalent strain and stress of the sealing structure show an increasing trend during the installation process. With the effect of the medium pressure, the maximum contact stress of the rubber seal ring increases from 2.6285 MPa at 20 ℃ to 2.6657 MPa at 0 ℃. The contact width decreases gradually with the decrease in temperature. With the initial compression rate increase, the maximum contact stress increases significantly. The simulation results show that the double-layer rubber O-ring structure still has good sealing performance at low temperatures.

ANALYSIS OF THE DESIGN OF THE SWELLING PACKER AND RESEARCH OF DAMAGE TO THE SEALING UNIT

The article provides a distinctive analysis of swelling packers used in different countries, considers the classification of packers. The principles of functioning of both mechanical packers and hydraulic packers, as well as swelling packers, are briefly considered, and their difference in functioning, opening time and holding time relative to swelling packers is also described. The advantages of swelling packers over other packages are presented. The superiority and key aspects of sealing elements of specifically swelling packers relative to mechanical and hydraulic packers are described, since some rubber materials included in the sealing element have the ability to self-repair sealing properties. The stages of development, properties of elastomers, which are used in the sealing elements of the packer, are given. Protective anti-extrusion rings are described, which protects the sealing units and elements from the indentation of the elastomer. The description of the varieties of swelling packers, the process of swelling, the advantages and disadvantages of swelling packers is given. The damage to the rubber of the sealing assembly of the swelling packer after testing in the well was analyzed. The elastomer of the sealing unit has been tested using various methods. The method of infrared spectroscopy revealed the approximate type of material and a change in the structure. Changes in the physicomechanical values of the rubber seal before and after thermo-oxidative aging are determined. The strength of the rubber polymer part of the packer from the effects of aggressive media was determined. Keywords: swelling packer, sealing unit, elastomer element, damage, mechanical packer, destruction, hydraulic packer, pressure, temperature.

Trends in Rubber and Plastic Seals Contributing towards Carbon Neutrality

Trends in Rubber and Plastic Seals Contributing towards Carbon Neutrality

Ocena efikasnosti investicije u proširenje kapaciteta preduzeća iz gumarske industrije

The aim of this paper is to determine and evaluate the economic efficiency of investment of the company from the field of rubber industry in the injection molding press and tool, with which the company expands the capacities intended for the production of rubber seals. The effects of the investment were estimated using the payback period, as a static method of investment efficiency evaluation, as well as the net present value and profitability index, as dynamic methods. In addition, in paper was used sensitivity analysis, as a method for evaluation of investment in conditions of uncertainty. The obtained results showed that the payback period of the investment is 2.93 years, while the net present value of the investment is 149,914 euros, and the profitability index is 1.79. All the obtained results indicate that the investment should be implemented. In addition, the sensitivity analysis, whose focus was primarily to consider the impact of increased material costs, on the results of the investment evaluation methods used, showed that the project is acceptable in all considered cases, because it contributes to increasing value of the company.

Влияние браслетной пружины на контактную нагрузку в соединении «Вал-манжета»

Reinforced rubber seals are used in bearing assemblies. Their reliable operation is ensured by pressing the working edge of the seal to the shaft. The contact load in the connection is affected by the force generated by the band spring. The presented method is used to determine the specific contact load of the working edge of the seal on the shaft offered by the bracelet spring, depending on the parameters of the seals and springs. To check the adequacy of the methodology, the authors studied a batch of reinforced seals 1.1‑45×65‑1 GOST 8752‑79 in the amount of 25 pcs. Theoretical calculations of the contact force from the action of the spring were 2.64 to 3.804 N, specific contact loads – 0.098 to 0.153 N/mm, and according to experimental data – 2.75 to 3.50 N and 0.102 to 0.141 N/mm, respectively. High convergence confirms the correctness of the presented calculated dependencies. It has been established that the parameters of the seals have a large spread, which hampers accurate calculation of the specific load in the “shaft-seal” connection. To increase the accuracy of readings, it is necessary to reduce the tolerances on the dimensions of rubber products.

Study on Preventive Maintenance Plan for Bridge Expansion Joint Rubber Seal using Superelastic Shape Memory Alloy

Study on Preventive Maintenance Plan for Bridge Expansion Joint Rubber Seal using Superelastic Shape Memory Alloy

Numerical Analysis via Mixed Inverse Hydrodynamic Lubrication Theory of Reciprocating Rubber Seal Considering the Friction Thermal Effect

This study investigates how operating conditions such as ambient temperature and sealing pressure affect sealing performance for a typical U-cup seal. The developed analysis method combines inverse fluid lubrication (IHL) theory and the Greenwood–Williamson contact model (G–W model), and the effect of increasing surface temperature due to frictional heat generated between two surfaces is considered. Commercial FE software (ABAQUS) was used to simulate the interference fit analysis of rubber seals and the pressurized process. Through this model, the film distribution, working fluid leakage, and friction force in the sealing area were discussed according to the operating parameters, such as sealed pressure, rod velocity, and ambient temperature. The simulation results demonstrate the effect of fluid viscosity on oil film formation (which varies with ambient temperature), the effect of increasing the surface temperature, and the effect of surface roughness at a very small film thickness.

Analytical solution of acoustic emission in soft material with cracks by using reciprocity theorem

Special property in soft materials manifests itself as slight external action may occur significant changes in structure or performance followed by crack initiation and propagation. Characterizing the transition from a crack-free to a cracked soft material remains one of the most challenging problems in structural changes. New methods are needed to predict when and how these soft materials will fail due to defects. In this context, we explored the acoustic emission phenomenon of a crack generation with micro-nanometer size in rubber seal rings. We found through the reciprocity theorem and equivalent body forces that this tiny structural change is defined by the opening crack time function, crack opening body and elastic constant. We take rubber as an example and analyze the new application of acoustic emission and propose a methodology for near surface crack detection of soft materials. Additionally, we discuss the contributions of the opening crack time function, cyclic frequency and elastic constant. The present ‘acoustic emission applications’ strategy offers an effective pathway to observe soft materials' structural changes.

Forecasting the Operation of Sealing Joints of Transport Locks of WWER-1000 and WWER-1200 Power Units in Operational Modes

The relevance of this work is determined by the need to predict the operation of sealing joints of transport locks of WWER-1000 and WWER-1200 power units in operational modes. The results of tests of rubber seals for tightness are given. Based on the study, the tightness of the rubber seals used was assessed and recommendations are developed to increase the reliability of the sealing joints of transport locks of WWER-1000 and WWER-1200 power units in operational modes.