Power Assessment of Flowing Compressed Air

Cai, Maolin; Kawashima, Kenji; Kagawa, Toshiharu

doi:10.1115/1.2170129

Cited by 124 publications

(69 citation statements)

References 1 publication

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“…Here, R is the universal gas constant (8.314 J/mol K), T is the gas temperature (298 K), and is the molecular weight of CO 2 (0.044 kg/ mol). The energy consumed per cycle (E c ) was calculated from E c = P 1 V 1 1n P 1 /P a [22]. Additionally, we calculated the initial stored energy of the bottle (E b ) using the equation E b = m/μ RT 1n P 1 /P a , where m is the mass of CO 2 in the bottle (0.255 kg).…”

Section: Empirical Characterization Of Ppafo System Performancementioning

confidence: 99%

A portable powered ankle-foot orthosis for rehabilitation

Shorter¹,

Kogler²,

Loth³

et al. 2011

JRRD

153

115

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Abstract-Innovative technological advancements in the field of orthotics, such as portable powered orthotic systems, could create new treatment modalities to improve the functional outcome of rehabilitation. In this article, we present a novel portable powered ankle-foot orthosis (PPAFO) to provide untethered assistance during gait. The PPAFO provides both plantar flexor and dorsiflexor torque assistance by way of a bidirectional pneumatic rotary actuator. The system uses a portable pneumatic power source (compressed carbon dioxide bottle) and embedded electronics to control the actuation of the foot. We collected pilot experimental data from one impaired and three nondisabled subjects to demonstrate design functionality. The impaired subject had bilateral impairment of the lower legs due to cauda equina syndrome. We found that data from nondisabled walkers demonstrated the PPAFO's capability to provide correctly timed plantar flexor and dorsiflexor assistance during gait. Reduced activation of the tibialis anterior during stance and swing was also seen during assisted nondisabled walking trials. An increase in the vertical ground reaction force during the second half of stance was present during assisted trials for the impaired subject. Data from nondisabled walkers demonstrated functionality, and data from an impaired walker demonstrated the ability to provide functional plantar flexor assistance.

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Section: Empirical Characterization Of Ppafo System Performancementioning

confidence: 99%

A portable powered ankle-foot orthosis for rehabilitation

Shorter¹,

Kogler²,

Loth³

et al. 2011

JRRD

153

115

View full text Add to dashboard Cite

show abstract

“…To monitor these systems, flow measurements are required [1][2][3][4]. In order to detect and quantify gas flow rates, non-invasive measurement techniques whose sensors are installed outside the gas pipelines and indirectly contact with gases are recommended, as these techniques have an evident advantage that it is not necessary to break pipelines to install sensors when measuring.…”

Section: Introductionmentioning

confidence: 99%

Soft Sensing Method Of LS-SVM Using Temperature Time Series For Gas Flow Measurements

Fan

Cai

et al. 2015

Metrology and Measurement Systems

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This paper proposes a soft sensing method of least squares support vector machine (LS-SVM) using temperature time series for gas flow measurements. A heater unit has been installed on the external wall of a pipeline to generate heat pulses. Dynamic temperature signals have been collected upstream of the heater unit. The temperature time series are the main secondary variables of soft sensing technique for estimating the flow rate. A LS-SVM model is proposed to construct a non-linear relation between the flow rate and temperature time series. To select its inputs, parameters of the measurement system are divided into three categories: blind, invalid and secondary variables. Then the kernel function parameters are optimized to improve estimation accuracy. The experiments have been conducted both in the single-pulse and multiple-pulse heating modes. The results show that estimations are acceptable.

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“…Cai et al [3,4] have shown that CA power (exergy rate) has two parts: (a) the transmission power used for pushing CA towards to the application side and (b) the expansion power, which can be used when CA is expanding after closing inlet valve. Although the latter represents the larger part of all CA powers above This energy is wasted during retract motion of the cylinder as CA is ventilated to the atmosphere.…”

Section: Application Sidementioning

confidence: 99%

“…The exergy represents the amount of useful energy, which can be theoretically converted to mechanical energy. It can be easily shown that in the case of CAS, only the pressure-dependent term is critical [3,4]. Equation (1) shows the mathematical formulation of exergy referenced to the ambient conditions (subscript a) based on ideal gas approach.…”

Section: Exergy Definitionmentioning

confidence: 99%

“…The data heve been used to estimate the efficiency during the motion of the actuator. The efficiency of the process can be defined by equation (4), where the numerator represents useful work W done by pneumatic forces F, while the denominator is the total energy of the incoming CA to the working chamber which can be utilized for the useful work from the start of the motion at time t 1 until the end of motion at time…”

Section: Application Sidementioning

confidence: 99%

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

Eret

Harris

O’Donnell

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part A:

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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.

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Power Assessment of Flowing Compressed Air

Cited by 124 publications

References 1 publication

A portable powered ankle-foot orthosis for rehabilitation

A portable powered ankle-foot orthosis for rehabilitation

Soft Sensing Method Of LS-SVM Using Temperature Time Series For Gas Flow Measurements

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

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