Application Of Compressed Air Research Articles

Pipe size calculation for compressed air supply

Pipe designers and engineers often encounter complex mathematical equations to determine the diameter required for adequate compressed air at specific flow velocities. This article aims to simplify the calculation of compressed air pipe sizes. The formulas and factors derived herein can be utilized for determining pipe diameters in compressed air applications. Ultimately, the findings provide engineers and designers with practical tools to enhance the reliability and efficiency of compressed air system.

Energy savings in compressed air systems a case of study

The compressed air applications are highly used in the industrial sector due to its easy transportation, safety, purity, cleanliness and storage capacity. In many regions, compressed air system accounts for about 10% of the industrial electricity energy bill. However, compressed air is expensive because around 30% of the consumed energy is used for these systems in an industrial facility. Energy used to be lost as leaks, pressure drops, heat, misuse, among others. Several energy efficiencies measures help to improve energy savings in companies such as: pressure reduction, reduce the inlet air temperature, use a well-calculated capacity tank for storage, control heat recovery and reduce leaks, giving potential energy savings in a range between the 20% to 60%, with a return of investment not higher than two years. As result, this document analyzes the energy efficiency measures that can be considered for compressed air systems applications, calculates the energy saving potentials, and assesses a case of study in a company in the city of Barranquilla.

Gravity Compressed -Air- Hydraulic- Power-Tower Energy Storage Plants

In the era of the increasing implementation of renewable energy sources in the electrical energy supply the demand for energy storage continues to grow. This is because the renewable energy sources, mainly in the form of wind and solar energy, are sustainable, but at the same time are subject to natural fluctuations. The wind does not always blow, and the sun does not always shine. Therefore, a stable and reliable power supply is more challenging than ever. It now must regulate fluctuating electricity demand and fluctuating electricity supply. At the same time decentralized energy supply systems based mainly also on PV and wind energy (e.g. as hybrid systems) storage requirement will become a key component of these local electrical energy supply networks especiallyy to balance the energy demand and supply. Among the many storage techniques an important example is the Hydro-Power-Tower an innovative hydraulic energy storage system based on pumped storage technology. Depending on the actual storage method that can be based on gravity (lifting / falling of weight in a vertical underground or above ground Tower), on air compression / decompression or on a combination of both techniques, can be distinguished the following Storage systems, Gravity Hydro Power Tower Storage (GHPTS), Compressed Air Hydro Power Tower Storage (CAHPTS) and Gravity Compressed Air Hydro Power Tower Storage (GCAHPTS).The GHPTS is the classic form of the Hydro Power Tower Storage and is widely discussed in the literature with scientific results and technical applications especially in the last decade. Besides the many advantages of (GHPTS) an important disadvantage is the very high weight and high cost of the tower piston (usually metal) which is the key component for potential energy storage. The storage based on Compressed Air is also widely applied in different storage systems but less so than Power Tower. Regarding the application of compressed air, in the PTS system, some own results are to mention, proposing a replacement possibility of the heavy overload piston of (GHPTES) using a part of the tower as a compressed air reservoir. The present study considers the combination of both storage techniques Gravity and Compressed Air integrated in a so-called Gravity-Compressed-Air-Hydro- Power- Tower - Storage (GCAHPTS). The combined influence of compressed air pressure and high of weight tower piston on the stored energy will be analysed. The obtained results allow the optimal design of such a combined power tower storage system. When the compressed air or high weight piston is missing on obtain GHPTS or CAPTS respectively.

Pressure drop in fibrous filters

Coalescing filtration is a mechanical process, which is employed to remove dispersed aerosol particles from a gas stream. This kind of filtration is a depth filtration process and it is widely used in process industries to remove particulate matter from exhaust gases, or in compressed air applications to filter oil particles introduced during compression. Fibrous filters are often used due to low cost, high capture efficiency and low pressure-drop, where droplets are first captured on fibres, then coalesce, and eventually drain out. The performance of a filter medium is judged based on its capture efficiency and its pressure drop characteristics. Estimating these parameters without setting up experimental investigations of each filter medium would be beneficial for choosing and developing optimal filters. In the present study, numerical simulations using ANSYS CFX© are used to predict the pressure drop caused due to the air flow through the randomly oriented fibrous filter medium. A fictitious domain approach is used to simulate solid fibres without the need to create a case-specific mesh for each different fibre alignment. The method is compared to a benchmark simulation and a mesh analysis is carried out to find a balance between mesh refinement and computational effort required. This method is extended to model 3D fibres with random orientations. Multiple simulations, each with a different randomized fibre alignment, is carried out, varying both Reynolds number and solidity, and the results are compared with theoretical and 2D simulation results. It is seen that both available theoretical models and 2D simulation results overestimate the pressure drop caused by a real fibrous filter which is attributed to the inherent random orientation of the fibres.

Application of compressed air in the online monitoring of surface roughness and grinding wheel wear when grinding Ti-6Al-4V titanium alloy

This work aimed to improve the surface quality and precision in machining process and speed up intelligent production. Hence, this work proposed a grinding process from a control perspective which provides a cognitive decision-making process. From this viewpoint, a new approach to measure the amount of grinding wheel wear and predict the surface roughness was designed by the authors on the basis of the compressed air measuring head and hybrid algorithms between fuzzy neural networks (i.e., ANFIS)—Gaussian regression function (i.e., GPR) and Taguchi empirical analysis. A series of experiments was conducted under different processing conditions. Results showed that the proposed method can measure the abrasive wear and predict the surface roughness accurately during Ti-6Al-4V titanium alloy grinding. The proposed model can predict surface roughness values with an error rate of 0.31% and a confidence interval of 98%. This study laid the foundation for monitoring the grinding wheel wear and the surface roughness in real-life industrial environments.

An intracooling system for a novel two-stage sliding-vane air compressor

Lube-oil injection is used in positive-displacement compressors and, among them, in sliding-vane machines to guarantee the correct lubrication of the moving parts and as sealing to prevent air leakage. Furthermore, lube-oil injection allows to exploit lubricant also as thermal ballast with a great thermal capacity to minimize the temperature increase during the compression. This study presents the design of a two-stage sliding-vane rotary compressor in which the air cooling is operated by high-pressure cold oil injection into a connection duct between the two stages. The heat exchange between the atomized oil jet and the air results in a decrease of the air temperature before the second stage, improving the overall system efficiency. This cooling system is named here intracooling, as opposed to intercooling. The oil injection is realized via pressure-swirl nozzles, both within the compressors and inside the intracooling duct. The design of the two-stage sliding-vane compressor is accomplished by way of a lumped parameter model. The model predicts an input power reduction as large as 10% for intercooled and intracooled two-stage compressors, the latter being slightly better, with respect to a conventional single-stage compressor for compressed air applications. An experimental campaign is conducted on a first prototype that comprises the low-pressure compressor and the intracooling duct, indicating that a significant temperature reduction is achieved in the duct.

Modeling and analysis of an open-drive Z-compressor

A rotary Z-compressor prototype for compressed air applications has been developed and tested. The Z-compressor working process resembles the one of a two-stage rolling piston compressor where the stages are phased by half rotation. In contrary to the traditional rolling piston design, the vane in a Z-compressor is positioned parallel to the main shaft and not perpendicular. In order to understand the impact of leakage and frictional losses and improve the design of such machine, a mechanistic model has been developed to include governing equations within the working chambers (i.e., two suction chambers and two compression chambers), leakage flow models, detailed mechanical analysis, one-degree of freedom valve model, in-chamber heat transfer and an overall energy balance of the compressor shell. The model has been validated with preliminary experimental data and then exercised to identify the potential performance improvements over a range of clearances and working conditions.

Design and analysis of a sliding vane pump for waste heat to power conversion systems using organic fluids

The current research work assesses the relevance of pumping work in energy recovery systems based on bottoming Organic Rankine Cycles (ORC) and presents the development of a sliding vane pump prototype for small scale units. The novel device was installed on an ORC-based power unit for waste heat to power conversion in compressed air applications in which the heat source was a compressor lubricant while the heat sink was tap water. Tests were performed with R236fa as working fluid at different pressure rises (3.9–9.7) and revolution speeds (500–1300RPM). The experimental dataset was used to validate a numerical one-dimensional CFD model of the sliding vane pump developed in the GT-SUITE™ environment. The model takes into account the fluid dynamics and friction phenomena that are involved in the pump operation such as vane filling and emptying, leakages as well as dry and viscous friction between components in relative motion. The modeling platform was further exploited to retrieve performance maps of the pump, angular vane pressure evolution as well as to break down leakage and friction losses. The effects of geometrical features on the pump performance were eventually investigated through variations of the aspect ratio. With reference to the best experimental operating point (pressure rise 9.7, revolution speed 1250RPM), simulations showed that, with a stator 5% bigger than the nominal one and an axial length almost halved, overall pump efficiency could be increased from the experimental 36.9% to a value of 48.0%

The effect of a compressed air stimulus on blocking times in a concentrate feeding station for horses in group housing

Concentrate feeding stations are used to meet the different feeding requirements of group-housed horses. In practice, blocking times caused by horses remaining in the feeding station without concentrate allowance constrain the feeding process considerably. To date, the application of an electric shock seems to be the most effective stimulus to prevent these blocking times.The aim of the present study was to examine the effectiveness of an innovative stimulation device in preventing the occurrence of blocking times. The study was carried out in a so called active barn, a group housing system with a generous space offer which is subdivided into different functional areas (resting, water intake, concentrate intake, roughage intake, paddock, pasture). Each of the 16 horses observed was fed with the help of a concentrate feeding station. As standard, the concentrate feeding station was equipped with a stimulation device that is intended to encourage the horses to leave the station after feed intake. The stimulation device consisted of an acoustic signal (beeper) and a touch trigger (thin stick) that should drive the horses from the feeding station. In the course of the present study, an additional stimulus was implemented, namely the application of compressed air between the horses’ hind legs. The behaviour of the horses was recorded with video observation and analysed over a period of 3×24h in each of the trial periods (1. Status quo=no application of compressed air; 2. Compressed air; 3. Compressed air after two weeks of application; 4. Compressed air after six weeks of application).It was observed that the average daily blocking durations, as well as the average daily blocking frequencies of the horses, could be reduced significantly by the application of compressed air. However, an increase of the observed blocking durations and blocking frequencies during the six weeks of the trial period indicates the occurrence of a habituation effect over time. In the course of the present study it became obvious that there are great individual differences concerning the reaction of the horses to the applied stimulation devices. As the emergence of blocking times is a very complex issue, the authors strongly recommend further scientific research on this topic. Possible future research focuses are discussed in the course of the present study.

Food and drink sector considers exhaust air quality

While there are stringent standards regulating the quality and specification of compressed air applications in the food and beverage production sector, there are no equivalent standards in place for exhaust air quality from vacuum pumps. Here, we look at the best way of managing exhaust air quality from vacuum pumps.

Technical note: Air compared to nitrogen as nebulizing and drying gases for electrospray ionization mass spectrometry.

In the present study we tested the application of compressed air instead of pure nitrogen as the nebulizing and drying gas, and its influence on the quality of electrospray ionization (ESI) mass spectra. The intensities of the signals corresponding to protonated molecules were significantly (twice) higher when air was used. Inspection of signal-to-noise (S/N) ratios revealed that, in both cases, sensitivity was comparable. A higher ion abundance after the application of compressed air was followed by a higher background. Another potential risk of using air in the ESI source is the possibility for sample oxidation due to the presence of oxygen. To test this, we selected five easily oxidizing compounds to verify their susceptibility to oxidation. In particular, the presence of methionine was of interest. For all the compounds studied, no oxidation was observed. Amodiaquine oxidizes spontaneously in water solutions and its oxidized form can be detected a few hours after preparation. Direct comparison of the spectra where nitrogen was used with the corresponding spectra obtained when air was applied did not show significant differences. The only distinction was slightly different patterns of adducts when air was used. The difference concerns acetonitrile, which forms higher signals when air is the nebulizing gas. It is also important that the replacement of nitrogen with air does not affect quantitative data. The prepared calibration curves also visualize an intensity twice as high (independent of concentration within tested range) of the signal where air was applied. We have used our system continuously for three months with air as the nebulizing and drying gas and have not noticed any unexpected signal deterioration caused by additional source contamination from the air. Moreover, compressed air is much cheaper and easily available using oil-free compressors or pumps.

‘The Modern Atlas’: compressed air and cities c. 1850–1930

This article provides an overview of pneumatic technologies in nineteenth- and early twentieth-century Western cities. As urban centres continued to grow and expand in the nineteenth century, networks of compressed air were introduced to provide public utilities and private services in a variety of domains, ranging from postal services to beauty parlours. Previously used in mining and large construction works, pneumatic technologies seemed to rival electricity towards the end of the nineteenth century in the provision of urban utilities. Eventually, however, these technologies did not prove flexible enough to keep up with rapid urban population growth and the expansion of cities themselves, nor were they able to become glorious symbols of urban modernity. Through an overview of compressed air applications as used in urban centres, particularly Paris and London, the article provides an insight into the relationship between technological networks and urban modernities from the perspective of this relatively neglected urban network and technology.

EDM with an Air-Assisted Multi-Hole Rotating Tool

In the present research work, an extensive experimental study of air-assisted rotary electrical discharge machining (AAEDM) of high chromium, high carbon die steel has been made. Investigations have been performed to study the process factor effect namely pulse-on time, discharge current, duty cycle, tool rotation, and air pressure on material removal rate (MRR) and electrode wear ratio (EWR). A comparative analysis of solid rotary tool electrode electrical discharge machining (REDM) and AAEDM has been presented. It was found that a high MRR and low EWR occurred in AAEDM as compared to the REDM process, under the same processing conditions. Use of a multi-hole tool provided better circulation of dielectric in the discharge gap, thus it improved the flushing efficiency of the process. The results showed that the application of compressed air has a favorable influence on MRR and EWR.

Performance Analysis of Directional Control Valve: An Overview

Directional control valves start, stop or change the direction of flow in compressed air applications. To understand the different applications of compressed air and how valves are used, one must first have knowledge of the kinds and types of valves used by industries. This paper studies local valve control of the electro-hydraulic system. The slow response of hydraulic control valve usually becomes the hold-up of whole system performance. Although fast valves (e.g. high-bandwidth servo-valves) are available, they are far more expensive than slow valves (e.g. proportional directional control valves). To improve the performance of proportional directional control valves, three different types of controllers are synthesized. Firstly, based on the pole zero cancellation technique, an open loop compensator is designed which requires the accurate valve dynamic model information; Secondly, a full state feedback adaptive robust controller (ARC) is synthesized, which effectively takes into account the effect of parametric uncertainties and uncertain nonlinearities such as friction force and flow force. Finally, an output feedback ARC controller is synthesized to address the problem of un measurable states. Keywords: valve, hydraulic device, Simulink.

Research and Application of Compressed Air Prediction Based on the Wavelet Neural Network

The wavelet neural network (WNN) is presented in the paper which based on the features of wavelet analysis and artificial neural network, and applied to predict the application of compressed air for an enterprise. The result shows that the precision of this model is quite effective. The model , therefore can be use to industry.

Prediction of Surface Roughness in Compressed Air Jet Assisted High Speed End Milling of Silicon Using Diamond Coated Tools

The majority of semiconductor devices are made up of silicon wafers. Manufacturing of high-quality silicon wafers includes numerous machining processes, including end milling. In order to end mill silicon to a nano-meteric surface finish, it is crucial to determine the effect of machining parameters, which influence the machining transition from brittle to ductile mode. Thus, this paper presents a novel experimental technique to study the effects of machining parameters in high speed end milling of silicon. The application of compressed air, in order to blow away the chips formed, is also investigated. The machining parameters’ ranges which facilitate the transition from brittle to ductile mode cutting as well as enable the attainment of high quality surface finish and integrity are identified. Mathematical model of the response parameter, the average surface roughness (Ra) is subsequently developed using RSM in terms of the machining parameters. The model was determined, by Analysis of Variance (ANOVA), to have a confidence level of 95%. The experimental results show that the developed mathematical model can effectively describe the performance indicators within the controlled limits of the factors that are being considered.

A practical approach to investigating energy consumption of industrial compressed air systems

While there are several best practice standards available for minimizing the energy requirement for compressed air use in an industrial context, moving to best practice often requires investment and operational change. In production facilities, there is often a reluctance to commit to this type of change without a clear view of the benefit. Furthermore, there is very little detailed information available in the open literature that allows even a qualitative assessment of priorities. In order to address this shortcoming, a practical approach is proposed to provide detailed compressed air consumption information throughout an industrial site. The energy of the compressed air is evaluated at each key element of the system and the typical end-use application profile assessed. Simple models of the consumption rates are used to relate duty cycle and device count with actual total consumption. This approach is complemented with a novel method of assessing the leak rate from the entire system, based on the pressure decay time. The method, referred to as the ‘end use catalogue’ has been demonstrated at a manufacturing site with a wide range of compressed air applications. The model has been used to identify the most significant energy-intensive compressed air applications and possible strategies to reduce the energy requirement. In the particular site used as a demonstration, it was found that open blowing operations (e.g. fluidizing) are the largest consumers of compressed air which are amenable to intervention. System leakage accounts for almost 21 per cent of the compressed air generated, representing an energy input of 432 kWh per day. It is concluded that this approach can help to identify priorities for optimizing compressed air use at an industrial site without compromising the production yield.

Beyond Leaks: Demand-Side Strategies for Improving Compressed Air Efficiency

Staggering amounts of compressed air are wasted or misapplied in otherwise well-run manufacturing facilities, often adding thousands of dollars in extra operating cost per year. The process of eliminating this expensive waste requires a thorough examination of each use of compressed air, as well as how the overall compressed air system is configured, operated, and managed. There are eleven important questions managers should answer for their compressed air applications to understand whether compressed air is the right tool for the job, how compressed air is applied, how it is delivered and controlled, and how the compressed air system is managed.

In Vitro Flowering and Fruiting of Capsicum fruitescens L.

Flowering and fruit production were obtained from cultured shoot tips of `California Wonder', `Super Cayenne', and `Zippy' peppers grown in a liquid Murashige and Skoog (MS) medium without growth regulators. Thirty-day-old pepper shoot tips, derived from seedlings germinated sterilely, were cultured in a 6-liter polycarbonate container coupled to an automated plant culture system (APCS). Plants were given ten daily, 30-minute, compressed-air applications at 300 ml/minute. These shoots began flowering after an additional 60 to 90 days in culture and flowered continuously thereafter. About 5% to 10% of the flowers set fruit. Maximum fruit size obtained was ≈25% to 75% of the size of fruit produced on plants grown in vivo. In contrast, no flowering occurred from shoot tips grown in 25 × 150-mm culture tubes containing agar medium and subcultured every 8 weeks to fresh medium. Immature fruit excised from plantlets grown in the APCS were cultured separately on agar medium containing 0.0, 0.1, 0.3, or 1.0 mg BA/liter with and without 0.1 mg NAA/liter. Isolated fruit grew best on MS medium with BA only and poorest on medium without growth regulators. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine (BA); 1-naphthaleneacetic acid (NAA).

The invention and early use of compressed air to exclude water from shafts and tunnels during construction

For over 100 years the application of compressed air to exclude groundwater from shafts and tunnels while under construction below the water-table and in permeable ground has been common practice. It is a most efficient expedient, for it will stabilize soils over a wide range of grain sizes, from coarse sand to fine silt, and it has been used at depths where the hydro-static head of the groundwater is equivalent to 40 or 50 lb/sq. in. In the standard texts brief reference is made to the early work of Sir Thomas Cochrane, Kt, M. Triger, John d'Urban Hughes and Dr Laurence Potts, but there has been some confusion as to the priority of their contribution to this branch of engineering practice. In this Paper the historical problems have been resolved. It has also been a matter for comment that M. I. Brunel made no attempt to apply compressed air to the Thames Tunnel which was under construction at the time when Cochrane's patent was granted. In his ‘tunnel diaries’ and among his letters to the Directors of the Thames Tunnel, now preserved in the Library of the Institution of Civil Engineers, there are references to Cochrane's invention which explain his attitude towards it. Pendant plus de cent ans, l'utilisation d'air comprimé pour éliminer l'eau souterraine pendant la construction des puits et des tunnels sous la nappe aquifère dans des sols perméables a été une pratique courante. C'est un procédé des plus efficaces car il stabilise des sols sur une grande gamme de granulomtrie allant du sable grossier au limon fin, et il a été utilise à des profondeurs où la charge hydrostatique de l'eau souterraine est équivalente à 40 ou 50 lb/in.2 Dans les textes de référence une brève allusion est faite au sujet des premiers travaux de Sir Thomas Cochrane, M. Triger, John d'Urban Hughes, et Dr Laurence Potts, mais il y a eu confusion quant à la priorité de leurs contributions à ce secteur de la pratique du génie civil. Dans cette étude les problèmes historiques ont été résolus. Le fait que M. I. Brunel n'ait pas tenté d'utiliser de l'air comprimé pour le Tunnel de la Tamise qui était en construction à l'époque où le brevet de Cochrane était accordé, a aussi été un sujet de commentaire. Dans son ‘journal du Tunnel’ et parmi ses lettres aux Directeurs du Tunnel de la Tamise maintenant conservés à la librairie de 1'Institut du Génie Civil, il y a des références à l'invention de Cochrane qui explique son attitude envers celle-ci.