International Journal of Fluid Power

Performance Analysis of a Pressurized Assembly with a Reinforced O-ring

2023-03-13T00:08:07+01:00

In industrial facilities, leaks from manufacturing equipment represent uncontrolled fugitive emissions. The most critical components in this equipment are the seals. Several types of seals are used and the most popular are flat seals and O-rings. These seals are subject to high clamping loads and pressures. The failure of the seals could seriously affect the safety of people, and also the environment by the leakage of toxic products.

In this work, the analysis of the mechanical and leakage behavior of the O-ring seal reinforced by a metal core and a conventional one when placed either between two plates or in a rectangular groove is presented.

Four finite element models, developed using Ansys software, are used to study the behavior of the assemblies in the four cases when clamping load and fluid pressure are applied.

This study shows that the introduction of a metal core inside an elastomer O-ring improves the sealing in pressurized installations. The comparison between the assembly without and with a groove shows that the installation of the two studied seals in a groove can protect them against the high stresses which can cause their deterioration and thus increase the probability of failure.

Facilitating Energy Monitoring and Fault Diagnosis of Pneumatic Cylinders with Exergy and Machine Learning

2023-02-11T17:43:26+01:00

Pneumatic systems are widely used in industrial production sectors. Increasing penetrations of Intelligent Manufacturing and Green Manufacturing are highlighting the drawbacks of pneumatic technology in terms of particularly low energy efficiency and low-level fault diagnosis intelligence. Here we propose that a combined energy-based maintenance and fault diagnostic approach for pneumatic systems could be a game-changer for pneumatics. In this study, a pneumatic cylinder with internal and external leakages is examined and a typical pneumatic experimental system is built. Exergy is adopted for evaluating the available energy of compressed air. Data-driven machine learning models, SAE + SoftMax neural network model and SAE + SVM model, are developed for fault detection and diagnosis. By comparing different machine learning methods with various pressure, flowrate, and exergy data, it is found that the diagnostic accuracy when using pressure and flowrate data is highly dependent on operating conditions, while the diagnostic accuracy when using exergy data is always high regardless of operating conditions. This indicates the promise of developing an exergy-based maintenance paradigm in pneumatic systems. Besides, with exergy and machine learning, more downstream faults can be detected and diagnosed with fewer upstream sensors. This study is the first attempt to develop an exergy-based maintenance paradigm in pneumatic systems. We hope it could inspire the following investigations in other energy domains.

A Review of Pilot-operated Hydraulic Valves – Development, Challenges, and a Comparative Study

2023-01-05T02:43:16+01:00

Hydraulic systems have been widely used due to their high power-to-weight ratio. Despite the growing instances of being superseded by the electromechanical counterparts at low power levels, the market was incapable of presenting alternatives for large-size applications. Additionally, in recent years, the demand for more significant heavy machinery (Mobile & Industrial) has increased, which led to the necessity of even higher flow and pressure Pilot-operated valves, despite the fact that these valves have several issues. One might think the alternative could be developing a hydraulic system that does not rely on Pilot-operated valves, but after decades of research, these systems could not get close to the performance of Pilot-operated Multistage valves.

The paper presents a comprehensive study of the progress accomplished from the year 2016 to early 2022 in hydraulic Pilot-operated valves; they are widely employed among ordinary valves, proportional valves, and state-of-the-art digital hydraulics. Higher efficiency will be a primary factor in the success of the new designs.

The academia presented several studies to improve the Pilot valves’ performance, but still, they are limited. There are no dramatic developments, and there are only a few upgrades.