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Static Systems for Producing Gas Mixtures
Published in O. Nelson Gary, Gas Mixtures, 2018
Pressurized systems are frequently used in the laboratory to produce large volumes of gas mixtures. Technically speaking, a pressurized system is a dynamic method, since the usual procedure is to mix moving gas streams. However, the process of making and storing mixtures of gases in an appropriate cylinder is generally termed a “static method” of calibrated gas mixture production. Pressurized systems are most easily obtained from commerical manufacturers at pressures of about 2500 psig. Higher pressures of 3500 to 6000 can be obtained on request for certain gases.97 Pressurized mixtures of gases and pure gases are available commercially in a wide variety of cylinder sizes (see Appendix P). They can be produced in sizes from large steel cylinders with volumes up to 220 ft3 to small aerosol cans, which are good for volumes up to several liters.98 They can, however be produced in the laboratory if certain basic equipment is available. The three main types of pressurized systems are gravimetric, partial pressure, and volumetric. The first two types are the most commonly used commercial techniques. However, all three types can be used efficiently to produce large volumes of standard gas mixtures from the parts per million to the percent range.
Gears and Reducers
Published in Don Renner, Hands-On Water/Wastewater Equipment Maintenance, 2017
13.58 In other reducers, lubrication is accomplished by the pressure method. An oil pump driven by one of the high-speed shafts, picks up oil from the case sump and delivers it to die gears and bearings. Oil that is sprayed onto the gears is further splashed around the inside of the housing and onto the bearings when the unit is in operation. The advantage of pressurized systems is that they are more positive than splash lubrication and also require less oil to accomplish lubrication.
Stationary Fuel Cells and Hybrid Systems
Published in Viorel Badescu, George Cristian Lazaroiu, Linda Barelli, POWER ENGINEERING Advances and Challenges, 2018
A. Moreno, V. Cigolotti, M. Minutillo, A. Perna
The higher operating pressure guarantees higher cell performance. Some basic studies have concluded that, by assuming equivalent design parameters, a pressurized system may have higher system efficiency over an atmospheric pressure system (Liu and Weng 2010).
Effects of different drying techniques on the quality and bioactive compounds of plant-based products: a critical review on current trends
Published in Drying Technology, 2022
Tarun Belwal, Christian Cravotto, M. A. Prieto, Petras Rimantas Venskutonis, Maria Daglia, Hari Prasad Devkota, Alessandra Baldi, Shahira Mohammed Ezzat, Lourdes Gómez-Gómez, Maha Mahmoud Salama, Luca Campone, Luca Rastrelli, J. Echave, Seid Mahdi Jafari, Giancarlo Cravotto
A newly developed technology that could be used as a drying treatment is Instant Controlled Pressure Drop (known in French as “Détente Instantanée contrôlée” as DIC). DIC drying involves elevated temperature and brief time shifts. It consists of a thermomechanical process that applies an instant pressure drop to change the texture of the material. In the first instance, this method requires a short heating step (10–60 s) with an applied high-pressure saturated steam injection (up to 1 MPa) into the previously vacuum-dried matrix. Subsequent vapor condensation and heating increases the moisture (0.1 g H2O/g).[23] The first vacuum guarantees good interaction between the steam and the sample and hence helps the flow of heat. In certain situations, compressed air may be used in DIC multicycle procedure as a pressurized agent. After the first phase of heating, an abrupt pressure (0.5 − 1 MPa) decrease in the direction of the vacuum (3–5 kPa) over only 10–60 ms which causes the product to self-evaporate water, generating vapor and considerable mechanical stress for extending the product. In addition, automatic water evaporation ensures quick cooling that prevents the thermal degradation of sensitive compounds, providing high quality products.[24] The pressure drop causes the moisture to swell rapidly, and changes the texture leading to higher porosity for improved moisture removal.[25]
Implementation of fuel additive MAZ 100 for performance enhancement of compressed natural gas engine converted from in-used gasoline engine
Published in Journal of the Air & Waste Management Association, 2020
Vinh Duy, Khanh Duc, Trung Nguyen Thanh, Long Dinh, Tuan Le Anh
As observed in the schematic, fuel additive is pressurized in a container (6) by compressed air to guarantee a constant injection pressure. Fuel additive has been supplied to the vaporizator by a liquid injector (5), which is controlled according to testing conditions for a suitable amount of fuel additive. Mass flow rate of fuel additive supplied to the intake manifold of the testing engine has been guaranteed around a constant proportion to the amount of supplying fuel at each testing condition by adjusting the injection command from the fuel additive controller (10). Because flow rate of fuel additive is relatively low, so that in the experiment, we use single port fuel injection system for additive supplying and the mass of fuel additive (ma) is determined by Equation 1:
Improved design of dust test chamber for uniform distribution of dust sedimentation rate
Published in Journal of the Chinese Institute of Engineers, 2019
Keh-Chin Chang, Jia-Wen Kuo, Yi-Da Chung
Four problems were identified to result in nonuniform distribution of dustfall in the original design of the dust test chamber and are given in the following: Pressurized air is directly supplied by an air compressor, which easily disturbs the air pressure in the air nozzles.The four air manifold pipes are not of the same length; in other words, the flow resistances in the four air manifold tube are not the same which results in different air injection pressure in each air nozzle.Air flow is injected directly toward powder pile which may splash powder along the air reflection direction.Exhaust pipe is installed on one side of upper chamber which leads to uneven pressure distribution in the test section.