scholarly journals Improving the lifetime of an electro-compressor for autoclave with optimized buffer tank

2021 ◽  
Vol 286 ◽  
pp. 01004
Author(s):  
Iulian Vlăducă ◽  
Claudia Irina Borzea ◽  
Carmen Gheorghiţa Petre ◽  
Romeo Dorin Hriţcu ◽  
Raluca Lucia Maier ◽  
...  
Keyword(s):  
Operating Time ◽  
Atmospheric Temperature ◽  
Automation System ◽  
Operational Parameters ◽  
Working Pressure ◽  
Increase Energy Efficiency ◽  
Hot Air ◽  
Custom Made ◽  
Buffer Tank ◽  
Start Ups

In order to increase the research capabilities in the field of lowweight intelligent materials and high structural performance, and also to increase energy efficiency, a study was conducted on improving the operating time of a hot air autoclave compressor with a buffer tank. The booster screw electro-compressor of 200 kW is designed to compress technological air to the installation’s necessary parameters at 1 ppm air purity, and the pressurized buffer tank is designed to reduce the number of start-ups of the compressor unit and its motor, in order to increase its lifespan. The pressure can vary in the designed buffer tank from 7 to 26 bar (abs). The autoclave parameters record thermodynamic modifications as it heats up to 400 °C at the working pressure. Cool air is required during the cooling process. The air mass exchanged during operation for cooling down to atmospheric temperature was calculated. The data obtained was used for validating an optimally designed buffer tank within the required operational parameters limits, set and acquired by the custom-made automation system.

The Effects of Operational Parameters in Hot-Air Vulcanisation

2016 ◽  
Vol 43 (10) ◽  
pp. 1-6 ◽  
Author(s):  
V. Schöppner ◽  
S. Brockhaus ◽  
C. Penner ◽  
J. Möckel
Keyword(s):  
Operational Parameters ◽  
Hot Air

scholarly journals Energy efficient modernization of KVG and TGV boilers

2021 ◽  
Vol 36 ◽  
pp. 22-35
Author(s):  
P. Glamazdin ◽  
D. Glamazdin
Keyword(s):  
Operating Time ◽  
Small Diameter ◽  
District Heating ◽  
Hot Water ◽  
Automation System ◽  
Convective Heating ◽  
Optimized Design ◽  
Efficient Design ◽  
Heating Systems ◽  
District Heating Systems

At present, the district heating systems of Ukrainian cities are in a critical state. They need significant modernization. This especially applies to very important components of district heating systems – heating water boilers. Unsatisfactory condition of boilers is mainly due to the obsolescence of basic equipment, including boilers. The operating time of them exceeds the passport lifetime. There ia a lack of modern automation, especially in terms of controlling operating modes. Nominal power of them exceeds the real heat loads. The range of hot water boilers used is not large. These are low-power boilers of the series NDIST, "Universal", "Energiia", "Fakel" and others, medium-power boilers of the series TVG and KVG and high-power boilers of series PTVM and KVGM. According to their prevalence, special attention should be paid to boilers of the series TVG and KVG. The series are installed on quarter boiler houses. The boilers of these series have an efficient design of the furnace volume and an optimized design of the convective part. Nevertheless, in terms of automation, gas supply and air supply systems, they no longer meet today's requirements. They are outdated comparing to the achieved level of technical solutions. The article discusses the main shortcomings of the design of boilers: insufficient durability of the gas collector in the hearth burner, small diameter of the pipes of the convective part and the use of fireclay materials in the setting of the burners. The first two shortcomings were overcome by the developers by the increase in the diameter of the pipes of convective packages and the modernization of MPIG-3 hearth burners. The third shortcoming should be overcomed by replacing the setting with a modern one during off-season repairs. Reserves for improving the energy efficiency of boilers of these series are found. To do this, it is necessary to install additional convective heating surfaces (economizers or air-heaters), replace the setting and equip the boilers with a modern automation system with cascading the burners. It allows improving efficiency up to 94...95 % and environmental performance according to the modern requirements.

Effects of Cropping Seasons and Temperatures on the Dormancy of Rice (Oryza sativa) Seeds

1983 ◽  
Vol 19 (4) ◽  
pp. 349-354
Author(s):  
H. P. Sikder
Keyword(s):  
Oryza Sativa ◽  
Relative Humidity ◽  
Air Temperature ◽  
West Bengal ◽  
Atmospheric Temperature ◽  
The Sun ◽  
Post Harvest ◽  
Hot Air ◽  
Breaking Dormancy ◽  
Cropping Seasons

SUMMARYThe Boro (dry) and Kharif (wet) seasons of West Bengal differ appreciably in respect of atmospheric temperature, relative humidity and hours of bright sunshine each day. Post-harvest hot temperature (31°C) either in controlled conditions (in the Kharif season) or in natural (31.5°C) conditions (in the Boro season) had a more significant effect than post-harvest cool air temperature (20.4°C) in the Kharif season on the early breaking of dormancy of paddy rice seeds. However, the pre-harvest hot air temperature (31.4°C) of the Boro season was no more effective in breaking dormancy than the pre-harvest cool air temperature (20.9°C) of the Kharif season. With a mean air temperature of 20.4°C the post-harvest exposure of the seeds to the sun from sunrise to sunset during the Kharif season was much more effective in breaking dormancy than the post-harvest mean air temperature of 31.5°C during the Boro season.

scholarly journals Preheating procedure for fast start-up of a steam turbine from a cold state

2019 ◽  
Vol 137 ◽  
pp. 01024
Author(s):  
Wojciech Kosman ◽  
Andrzej Rusin
Keyword(s):  
Steam Turbine ◽  
Thermal State ◽  
Initial Period ◽  
Electric Heater ◽  
Cold State ◽  
Hot Air ◽  
Start Up ◽  
Maximal Stress ◽  
Fast Start ◽  
Start Ups

The paper describes a procedure that allows to start up a steam turbine in a significantly shorter period. The procedure is developed for start-ups that begin from a cold state, when the temperature of the parts of the turbine is close to the ambient temperature. The pre-heating rises the parts temperature before the actual start-up begins. It changes the thermal state of the turbine and causes smaller maximal stress during the initial period of the start-up. The procedure involves a pre-heating of the turbine with a hot air generated in an electric heater. The paper describes the requirements of the process. It presents the possible configurations of the flow in the turbine and the analysis of the thermal and the strength state of the turbine during the pre-heating.

Flammability of High Flash Point Liquid Fuels

2012 ◽  
Author(s):  
Peter J. Kay ◽  
Andrew P. Crayford ◽  
Philip J. Bowen ◽  
James Luxford
Keyword(s):  
Gas Turbine ◽  
Heated Surface ◽  
Health And Safety ◽  
Atmospheric Temperature ◽  
Flash Point ◽  
Research Centre ◽  
Potential Hazard ◽  
Working Pressure ◽  
Hazardous Area ◽  
Accidental Releases

Current European Health and Safety Legislation was implemented to limit the chance of a serious explosion occurring in the workplace by highlighting potentially explosive atmospheres and ensuring that ignition sources are not present in these areas. Though hazardous area classification for gaseous and dust explosion hazards are well established, the same cannot be said for mists especially for high flash point liquids. However, a recent literature review of a range of (some fatal) incidents has shown that mist explosions are more common and the consequences more severe than previously anticipated. This work is, for example, applicable to the safe use of fuels and lubricants utilised in the gas turbine power generation and propulsion industries. Previous studies of jet breakup regimes and idealised flammability studies have indicated that low pressure releases (<10 bar) of low volatility fuels may still give rise to combustion hazards. Impingement of accidental releases onto surfaces has been shown to exacerbate the potential hazard, or broaden the range of hazardous release conditions. However, although a theoretical case can be made for generating flammable environments under moderate release conditions, very little evidence has been provided to bridge the gap between ‘idealised’ studies and full-scale incidents. The aim of this first programme of work is to start the process of bridging this gap, leading to well founded safety guidance. The test programme was conducted in a custom built spray chamber located in the Gas Turbine Research Centre (GTRC) of Cardiff University. The fuel was released at a predefined range of pressures of industrial relevance at atmospheric temperature. Igniters were positioned at three downstream locations and the continuous electrical discharge had an energy no greater than 4 mJ. Tests were conducted for ‘free sprays’ where the spray was directed along the length of the chamber, and for impinging sprays where the spray was aligned to impinge normal to a flat un-heated surface. Gas oil (flash point > 61 °C) ignited as a free jet at a working pressure consistent with previous hypotheses. However, when the jet impinged on a solid surface then the resulting spray could be ignited at considerably lower delivery pressures. Although the impingement process is complex, the data will be discussed in light of contemporary models that predict initial jet/spray characteristics along with post-impingement characteristics. This paper presents a first step towards consolidating previous studies and improving future safety guidelines concerned with the risk posed by the flammability of accidental releases of pressurised high flashpoint fuels.

scholarly journals Modelling Spray Pressure Effects on Droplet Size Distribution from Agricultural Nozzles

2021 ◽  
Vol 11 (19) ◽  
pp. 9283
Author(s):  
Emanuele Cerruto ◽  
Giuseppe Manetto ◽  
Rita Papa ◽  
Domenico Longo
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Droplet Size Distribution ◽  
Drop Size Distribution ◽  
Pressure Effects ◽  
Hollow Cone ◽  
Immersion Method ◽  
Color Code ◽  
Working Pressure ◽  
Custom Made

For spray applications, drop size is the most important feature as it affects all aspects of a phytosanitary treatment: biological efficacy, environmental pollution, and operator safety. In turn, drop size distribution depends on nozzle type, liquid properties, and working pressure. In this research, three nozzles were studied under ordinary working conditions and the effect of pressure on drop size distribution was assessed. The nozzles under test, all from Albuz (France), were an orange hollow cone nozzle ATR 80 (European color code), an air induction flat spray nozzle AVI 11003, and an air induction hollow cone nozzle TVI 8002. The ATR 80 and the TVI 8002 nozzles were tested at four pressure values: 0.3, 0.5, 1.0, and 1.5 MPa; the AVI 11003 nozzle was tested at 0.3 and 0.5 MPa. The drop size measurement technique was based on the liquid immersion method by using a custom-made test bench; spray quality parameters were computed by means of suitable functions written in R language. Results showed that an increase in working pressure caused an increase in drop pulverization regardless of the type of nozzle, and drop pulverization was higher for the turbulence nozzle than for the two air induction nozzles. Based on skewness and kurtosis values, the theoretical gamma distribution was the most adapt to fit the experimental data. The scale parameter showed a decreasing trend with the increase in the pressure, a clear index of higher drop pulverization.

scholarly journals Recycling and melting process of the zirconium alloy chips

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Luis Augusto Mendes Reis
Keyword(s):  
Continuous Flow ◽  
Zirconium Alloy ◽  
Melting Process ◽  
Cutting Fluid ◽  
X Rays ◽  
Cleaning Process ◽  
Recycling Process ◽  
Hot Air ◽  
Custom Made ◽  
Storage Volume

The aim of this work is study on the recycling process of zirconium alloy chips and the results aiming the efficiency in the cleaning process; the quality control; the obtaining of the pressed electrodes and finally the melting in a Vac-uum Arc Remelting furnace (VAR). The recycling process begins with magnetic separation of possible ferrous al-loys chips contaminant, the washing of the cutting fluid that is soluble in water, washing with an industrial degreas-er, followed by a rinse with continuous flow of water under high pressure and drying with hot air. The first evalua-tion of the process was done by an Energy Dispersive X-rays Fluorescence Spectrometry (EDXRFS) showed the presence of 10 wt. % to 17 wt. % of impurities due the mixing with stainless steel machining chips. The chips were then pressed in a custom-made matrix of square section (40 x 40 mm - 500 mm in length), resulting in electrodes with 20% of apparent density of the original alloy. The electrode was then melted in a laboratory scale VAR furnace at the CCTM-IPEN, producing a massive ingot with 0.8 kg. It was observed that the samples obtained from In-dústrias Nucleares do Brasil (INB) are supposed to be secondary scrap and it is suggested careful separation in the generation of this material. The melting of the chips is possible and feasible in a VAR furnace which reduces the storage volume by up to 40 times of this material, however, it is necessary to correct the composition of the alloy for the melting of these ingots.

scholarly journals The effectiveness of antibiotic cement-coated nails in post-traumatic femoral and tibial osteomyelitis – comparative analysis of custom-made versus commercially available nails

2021 ◽  
Vol 6 (9) ◽  
pp. 457-466
Author(s):  
Germán Garabano ◽  
Hernán del Sel ◽  
Joaquin Anibal Rodriguez ◽  
Leonel Perez Alamino ◽  
Cesar Angel Pesciallo
Keyword(s):  
Comparative Analysis ◽  
Infection Control ◽  
Failure Rate ◽  
Operating Time ◽  
Consecutive Series ◽  
Antibiotic Cement ◽  
Custom Made ◽  
Initial Injury ◽  
Post Traumatic ◽  
Reoperation Rates

Abstract. Background: The first objective of this retrospective study was to assess infection control rates in patients with chronic post-traumatic osteomyelitis (CPTO) of the femur or tibia treated with antibiotic cement-coated nails. The second objective was to compare the efficacy of custom-made nails versus commercially available antibiotic-coated nails in terms of infection control and need for reoperation. Methods: We reviewed a consecutive series of CPTO patients treated with antibiotic-coated nails who had a minimum follow-up of 24 months. We recorded the characteristics of the initial injury, the type of nail used, cement–nail debonding, infecting microorganisms, operating time, infection control, need for reoperation, and failure rate. We performed a comparative analysis between nails manufactured in the operating room (i.e., custom-made) and those commercially available. Results: Thirty patients were included. The affected bones were the femur (n=15) and the tibia (n=15). Twenty-one of the 30 initial injuries were open fractures. Staphylococcus aureus was the most frequently isolated microorganism (50 %). Sixteen patients were treated with custom-made nails and 14 with commercially available antibiotic-coated nails. At the time of extraction, four out of five custom-made antibiotic-coated nails experienced cement–bone debonding. Commercial nails were associated with shorter operating times (p<0.0001). The overall infection control rate was 96.66 %. Eight (26.66 %) patients needed reoperation. There was one failure (3.33 %) in the group treated with custom-made antibiotic-coated nails. We did not find significant differences between nail types in terms of reoperation, infection control, and failure rate. Conclusions: The use of antibiotic cement-coated nails proved useful in CPTO treatment. Commercially available nails had significantly shorter operating times and did not present cement–bone debonding during removal. Our results seem to indicate that both nail types are similar in terms of infection control and reoperation rates.

Electrophoretic Deposition of Smectite Particles onto Cupper Plate

2009 ◽  
Vol 412 ◽  
pp. 195-200
Author(s):  
Hideo Watanabe ◽  
Hideki Matsushima ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Electrophoretic Deposition ◽  
Layer Structure ◽  
Operating Time ◽  
Exchange Capacity ◽  
Operational Parameters ◽  
Ion Exchange Capacity ◽  
Plate Electrode ◽  
X Ray ◽  
Atomic Force ◽  
Layered Clay

Layered clay has been of great interest because of their nano-sized layer structure and hence intercalation and ion-exchange capacity to be used as a host material of composite with polymers and/or metals. In this study, smectite as a silicate-layered clay was easily exfoliated and dispersed into purified water, and was deposited onto a cupper plate for which dc voltage ranging from + 1.0 V to + 6.0 V was applied with respect to a counter platinum plate electrode. The cupper plate was pre-treated by chemical and chemical mechanical polishing (CP and CMP) prior to the electrophoretic deposition (EPD). The surface roughness of the substrate as well as the smectite film formed was characterized by an atomic force microscope (AFM). The thickness of smectite layer was estimated using an X-ray fluorescence (XRF) analysis as well as a scanning electron microscope (SEM) observation. The layer thickness can be described as a function of operational parameters such as applied voltage and operating time. Smooth smectite film with thickness ranging from 100 nm to 10 μm has been successfully fabricated onto the CMP cupper plate by the EPD method in this study.

Study on Crack Propagation Tendencies of Non-Repaired and Repaired Nozzles

2003 ◽  
Author(s):  
Tomoharu Fujii ◽  
Takeshi Takahashi
Keyword(s):  
Crack Propagation ◽  
Gas Turbines ◽  
Power Plants ◽  
Operating Time ◽  
Distinctive Features ◽  
Inspection Interval ◽  
Start Ups

A system designed to control and predict the length of cracks that generate in the first-stage nozzles of E and F class gas turbines was developed. This system consists of three programs for (1) inputting cracks, (2) displaying cracks, and (3) predicting cracks, and a database consisting of approximately 350,000 cracks generated in first-stage nozzles taken from past repair records of five power plants operating in Japan. The database also contains data on operating time and number of starts of gas turbines. The distinctive features of this system are described below. 1) The crack data can be entered on the nozzle drawing as a picture by using the mouse. 2) The accumulated data allows the sections of nozzles in which cracks have generated most frequently to be identified. 3) The correlation formula of cracks and operating time or number of starts can be obtained simply. 4) By entering the scheduled operating time or number of start-ups to the time of the next scheduled inspection in the correlation formula, the length of cracks in optional sections and propagating in optional directions can be predicted. Using this system, the statuses of cracks generated in nonrepaired and repaired nozzles of E class gas turbines were compared. The comparison focused on 11 patterns with comparatively long cracks selected from the cracks propagating together with the increase in operating time or number of starts. The propagation of cracks covering a period of approximately two years, which corresponds to the inspection interval of power plants in Japan, was also compared. The results showed that the extent of crack propagation tends to increase with the increase in the number of repairs. Furthermore, the propagation of cracks in repair nozzles is about two times greater than that in non-repair nozzles. It was also found that the system could identify the sections in which the longest cracks are generated.

Sign in / Sign up

Export Citation Format

Share Document