Air Door Research Articles

Study of Cold-State Aerodynamic Field Test on the Outlet of 2150t/h Supercritical Once-Through Boiler

The new unit putting into production is the supercritical boiler with a level of or above 600 MW, and most of them take the corner tangential combustion technology. The Long-term operation practice shows that there is gas temperature deviation on all the horizontal flues of boilers, which usually leads to the overheating tube burst of the high-temperature superheater and reheater, thus threats the safe and economic operation of power station. Towards the gas temperature deviation phenomenon that exists commonly in tangentially fired boiler, this paper went on the pertinent cold-state aerodynamic field test on the tangentially fired boilers in one new power plant and studied the airflow velocity at the furnace outlet in eight vertical levels by changing the SOFA horizontally rotating angle. The experiment showed that changing the baffles opening and horizontally rotating angle of SOFA air door could adjust airflow quite well and make it uniform, furthermore, the airflow can reach a basic balance at the biggest anti-tangential angle. This paper has some reference value towards improving the gas temperature deviation problem of tangentially fired boilers.

Feasibility Study on the Boiler Induced Draft Fan Energy Saving Frequency Conversion Retrofit

Aiming at the badly needed goal of energy saving, the retrofit is implemented by adopting the stepless speed regulation of motor driving by the high-voltage inverter to regulate the air quantity. The inverter is taken its character of easy manipulation, small maintenance, high control precision as the advantage to replace the traditional device like air door operated and wind deflector operated methods. Furthermore, the feasibility analysis for the energy-saving effect after retrofit will be conducted. It has been concluded that there are obvious improvements both in energy saving and operational stability after the frequency conversion retrofit on the machine.

Experiment and Analysis on Temperature Distribution of Straw Double-Grate Briquette Boiler Furnace-Tank

Under 4 different conditions (the smallest air door αpy =1.60, the smaller air door αpy =2.20, the larger air door αpy =3.16 and the largest air door αpy =4.41), the double fire grates boiler designed by the author have been tested. The corresponding result is that the temperature distribution appears similar law in height, depth and width. Secure, stabile and economical operation of the boiler has been realized on the better work state (between condition 2 and condition 3). It will be an important type of straw briquette boiler. It lays foundation for optimization design of burning equipment and running adjustment.

Research on the Air Leakage Law and the Control Technology of the Main Air Doors of the Mine

Air leakage of the main air doors in the mine deteriorates the underground working environment and threatens both the safety production and the physical and mental health of workers. Based on the complex air-leaking problems of the main air doors, this paper has worked out a method by combining SF6 tracer technique and pressure energy test together. In this way, the air leakage law of the main air doors between the intake and the return airway of SHAOYAO coal mine has been determined: the total air leakage of the 10 sets of main air doors amounts to 499. 33m3/min; the amount of air leakage has positive correlation with the differential pressure of air leakage; on the basis of the law of air leakage resistance, the windage resistance of the main air doors has been calculated. According to the air leakage features of the main air doors, this paper also puts forward the control technology, such as spraying polyurethane foam, keeping the tightness of doorframe, etc. After field application, the amount of air leakage has decreased 56.1% on average. And accordingly, the air leakage of the main air doors has been effectively controlled and the underground working environment has been greatly improved.

Destruction mechanism of gas explosion to ventilation facilities and automatic recovery technology

In order to overcome the heavy casualties caused by gas explosion, we verified the propagation law of shock wave in pipeline and the overpressure distribution of gas explosion by similar experiments according to the analyses of reasons for casualty and ventilation system model destroyed by gas explosion in the mining face. We summarized the gas composition after the explosion and its danger, analyzed the effects of the gas explosion shock wave to ventilation system and facilities and the laws of toxic gas spread and diffusion in the ventilation network after the explosion. We presented a technical proposal to control the smoke and recover the ventilation system after a gas explosion and developed a reserve air door and control system that were embed in the lane, and could close automatically in conditions of no pressure and electricity. The results showed that the reserve air door normally opened and could close automatically controlling the smoke flow and resuming the ventilation system when the gas explosion shock wave destroyed the original shutting air door which resulted in the air short circuit.

Experiment and Analysis on Temperature Distribution of Peanut Shell Molding Fuel Hot-Blast Stove Furnace Chamber

Under four different working conditions (the smallest air door αpy =1.20,the smaller air door αpy =1.60, the larger air door αpy=2.30 and the largest air door αpy=3.50), the Peanut shell molding fuel Hot-blast Stove designed by the author have been tested. The corresponding result showed that the temperature distribution had similar rules in height, depth and width. The more reasonable and economical operations of the Peanut shell molding fuel Hot-blast Stove have been realized under the working condition 2 and 3. Their combustion efficiency of the boiler can reach 84.95％-92.07％and the thermal efficiency can reach 46.68％-56.73％. They have provided an effective way to solve the problem of heating in rural areas.

Ward assessment of SmartIdeas Project: bringing source isolation to the patient

Most UK hospitals lack enough single rooms to provide source isolation for all infected patients. The aim of this study was to test prototype isolation systems on general wards together with specifically designed portable sink units and toilets. Questionnaires were offered to staff, patients and visitors covering ease of use and acceptability. A total of 53 patients were isolated, with concurrent collection of environmental samples and staff hand hygiene audit. Blocking of beds next to infected patients was avoided but patients and staff were concerned about limited space and communication. Hand hygiene compliance on entry or exit to/from an isolated bed space significantly improved [43/76 (56.6%) to 107/147 (72.8%), P<0.05]. Although popular, the toilets were mechanically unreliable. Low levels of microbial contamination (<1-3.4cfu/cm(2)) were present within all isolated bed spaces. The highest colony counts were obtained from high contact sites (e.g. remote controls). Meticillin-resistant Staphylococcus aureus (MRSA) was present at similar levels inside all systems. Although one system was designed to provide airborne as well as contact isolation, MRSA was isolated from air inside and outside the system suggesting poor efficiency of the air door. The finding was confirmed by aerobiology tests at the Health Protection Agency Laboratory, Porton Down, UK. A trial of redesigned units is required to establish efficacy (Trial Identifier: ISRCTN02681602).

Infection Risk of Indoor Airborne Transmission of Diseases in Multiple Spaces

This study aims to predict the spatial distribution of infection risk of airborne transmission diseases in hospital anterooms and isolation rooms, using computational fluid dynamics (CFD) with the Wells-Riley equation. This is in order to make a case for a particular arrangement of supply and exhaust air vents and door gaps. The spatial distribution of the infection risk of measles, influenza, and rhinovirus (ranging from high to very low infectious agents) and the airflow pattern of room air were investigated. The influences of door gaps (1mm and 20mm widths) and supply air (12 and 24 air changes per hour into the isolation room) on the probability of infection for a susceptible population are analyzed. Results concerning the impacts of these parameters on the flow field of room air movement, the concentration contour of exhaled gas, and the airborne transmission infection risk are addressed in this paper.

Gamma-ray measurements of naturally occurring radioactive sample from Alkharje City

A survey was carried out to determine radioactivity concentrations and associated dose rates from the naturally occurring nuclides 232 Th, 238U and 40K in various surface soil formations of Alhkraje city. Samples were collected from different areas of the study, sieved through a fine mesh, sealed in 0.5-liter plastic Marinelli beaker, and measured in the laboratory for 24 hours each. From the measured g-ray spectra, radioactivity concentrations were determined for 232 Th ranging from 5.32±2.59 to 16.40±2.04 Bq . kg-1, 238U (2.87±0.18 to 18.83±0.81 Bq . kg-1), 40K (211.33±55.04 to 378.97±36.46 Bq . kg-1) and 137Cs (0 to 3.19±1.02 Bq . kg-1). Absorbed dose rates in air doors were calculated to be in the range of 15.29±2.65 to 30.00±3.24 nGy . h-1, the corresponding effective dose rates per person outdoors were estimated to be between 21.00±0.95 to 36.83±2.11 mSν. y-1, assuming a 20% occupancy factor.

Ventilator fan design: Present state and some prospects

1. Nominal (rated) static efficiencies of mine ventilators and the weighted-mean values in the normal region of operation do not characterize their operational cost effectiveness, which is determined by the weighted mean efficiency calculated over the whole region of their possible operation. 2. Production-line axial and centrifugal ventilators have approximately equal weighted mean static efficiencies, the values of which (0.54–0.58) are much lower than the rated efficiencies of production-line machines (0.8–0.86) and are close to the mean value of the operational efficiencies of acting ventilators (0.5–0.54). 3. The required ventilation regimes of mines continually change; therefore to ensure cost effectiveness of operation of ventilators and to increase the efficiency of ventilation systems it is necessary to increase the adaptive properties of ventilation plants; this can be most effectively accomplished by sectionalizing the axial ventilators and replacing the equipment in the ventilation plants. 4. Sectionalized axial ventilators with not more than three sections (stages) can give the required range of pressures, have higher weighted mean static efficiencies (0.656), and permit the creation of ductless ventilator plants with high adaptive properties. 5. Ventilation plants with centrifugal ventilators and controlled drives are more expensive, less reliable, and less cost effective; therefore they should not be used in mines with deep changes in the required pressure and throughput. 6. The present method of duplicating the whole system in main ventilation plants and having no standby switching air door systems reduces the reliability of ventilation plants below the level for safe conduct of underground operations. 7. The most promising system for mine ventilation comprises ductless ventilation plants with vertical sectionalized axial fans with synchronous drives.

NATAL, BRAZIL: SOUTH AMERICA'S “AIR DOOR.”

School Science and MathematicsVolume 28, Issue 8 p. 863-863 NATAL, BRAZIL: SOUTH AMERICA'S “AIR DOOR.” First published: November 1928 https://doi.org/10.1111/j.1949-8594.1928.tb00578.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume28, Issue8November 1928Pages 863-863 RelatedInformation