จะดีไหม ถ้าคนไทย เริ่มสร้างแรงจูงใจโดยการลดภาษีให้กับผู้ที่ลดการใช้พลังงาน โดยติดฉนวนในบ้าน
จากข่าวข้างล่างนี้ ที่อเมริกา เค้าเริ่มกันแล้ว โดยการให้สิทธิประโยชน์ในการลดภาษีจากผู้ที่ติดตั้งฉนวนในบ้าน
เราเริ่มทดลองใช้ฉนวนยางดำ หนาประมาณ 10 มิลลิเมตร ไปปูไว้บนฝ้า ปรากฎว่า มันทำให้เราปิดแอร์ได้ทุกวันได้เร็วขึ้นถึง 1 ชั่วโมง มันก็ไม่เลว นะ เพราะว่า ประหยัดแอร์ไปได้วันละชั่วโมง เดือน ละ 30 ชั่วโมง ปีละ 365 ชั่วโมง ประหยัดเงินไปได้ปี ละประมาณ 3800 บาทต่อปี (กรณีใช้เครื่องประมาณ 1800 BTU)
ไม่เลวนะจ๊ะ ลงทุนในห้องประมาณ 36 ตร.ม. ใ้ช้เงินประมาณ 4500 บาท คืนทุนประมาณ 14 เดือน ก็ได้ค่าฉนวนคืนมาแล้วนะคะ ใครอยู่คอนโดฯ บ้านอากาศร้อนมากๆ ก็ลองดูซะหน่อย ไม่แพงเกินไปหรอกนะ จะบอกให้
แต่อย่าลืมถ้าบ้านไหน หน้าต่างหันตรงกับแดด ใช้่ผ้าม่าน หรือกั้นฉนวนยิ่งช่วยนะคะ
Mechanical Insulation Installation Incentive Act of 2009 Introduced in House of Representatives
Rep. Deborah Halvorson (D-IL) presented House Resolution 4296 on December 11, 2009, to amend the tax code to provide an incentive to install and maintain mechanical insulation. The Mechanical Insulation Installation Incentive Act (MIA 09) creates an incentive for commercial and industrial entities to go beyond current minimum requirements for mechanical insulation systems (as defined by the American Society of Heating, Refrigeration, and Air-Conditioning Engineers 90.1-2007) in new construction or retrofit projects, as well as execute timely maintenance. This tax incentive will create jobs, boost energy efficiency, and reduce carbon emissions, helping reduce our country's dependence on foreign energy sources, protecting our environment, and stimulating our economy.
Mechanical insulation encompasses thermal, acoustical, and personnel safety requirements for mechanical piping and equipment and heating, ventilating, and air conditioning applications. It is used in a variety of commercial buildings and industrial facilities, including power plants, refineries, hospitals, schools, universities, government and office buildings, high-rise multi-family dwellings, hotels and motels, and retail and wholesale establishments.
MIA 09 provides facility owners an incentive to increase the use of or maintenance of mechanical insulation by lowering their tax expense in the fiscal year in which the mechanical insulation was put in service or maintenance completed. If the property owner is not subject to U.S. income tax, the tax deduction would transfer to the primary contractor for the property, providing an incentive for energy efficiency regardless of the property owner's tax status.
The incentive will reduce the time it takes for the energy cost savings to pay for the initial investment by 37 percent to 69 percent for new construction or retrofit and 16 percent to 23 percent for maintenance applications. It will also support the development of more than 89,000 sustainable jobs for skilled craft personnel to install and maintain the mechanical insulation systems, in addition to technical/engineering, manufacturing, sales, administrative and supporting craft jobs.
This initiative is supported by NIA and International Association of Heat and Frost Insulators and Allied Workers. For more on MIA 09, please visit www.insulation.org/mimi.
วันพุธที่ 20 มกราคม พ.ศ. 2553
วันอาทิตย์ที่ 27 ธันวาคม พ.ศ. 2552
ฉนวนสำหรับงานเย็น cryogenic
ใครจะรู้ว่านวตกรรมล่าสุด มีการนำฉนวนโฟม Elastomeric foam มาใช้กับงานเย็นที่อุณหภูมิต่ำถึง -196 องศาเซลเซียส โดยทั่วไปนิยมใช้ พอลิยูรี่เธน หรือ foam glass
แต่ฉนวนแบบเก่าที่ใบ้กันอยู่มักมีปัญหา under insulation corrosion, UIC
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แต่ฉนวนแบบเก่าที่ใบ้กันอยู่มักมีปัญหา under insulation corrosion, UIC
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วันพุธที่ 9 ธันวาคม พ.ศ. 2552
FESI : Acoustic insulation
ได้พบเนื้อหา เกี่ยวกับการทำงานเกี่ยวกับการลดเสียงในสถานที่ต่างๆ ซึ่งเป็นมาตรฐานของทางยุโรป น่าสนใจมากหาลิงค์ และอ่านได้ที่
http://www.fesi.eu/Page.aspx?pageType=NewsItem&pageID=270
Acoustic Solutions: A European Perspective
By Rennecke Hans-Joachim
Increasing population density and mobility, and mechanization of workplaces, households, and leisure activities, have resulted in increased general noise exposure for most people. The consequences for many are concentration and sleep disturbances, noise-induced hearing loss (noise deafness), and damage to the nervous system in the form of stomach, heart, and circulatory problems. According to statistics from the European Agency for Safety and Health at Work, approximately 22.5 million people in Europe suffered from hearing impairment due to noise in 2001, and about 2 million were considered extremely deaf. The costs of hearing impairment have been estimated at EUR 78 billion per year. Noise deafness is regarded as the most important and most recognized occupational disease, predominantly affecting men who work in manufacturing, construction, and transportation.
The general increase in exposure to noise has raised interest in the issue of noise protection and acoustic problems. The Acoustic Commission of the European Federation of Associations of Insulation Companies (Fédération Européenne des Syndicats d’ Entreprises d’Isolation—known as FESI) deals with these problems and assists its members with regard to acoustics and noise protection by providing information, including a series of six documents that address noise and noise protection. The documents can be used as a reference by planners, craftsmen, and contractors, but they are also applicable for training and studies. They provide detailed information about materials and systems and help users understand, evaluate, and solve acoustic problems. The idea behind the documents is to form a bridge between international directives and standards and practice-oriented application.
Document A2:
Basics of Acoustics
Acoustics is the science of sound and its influence on human beings. Document A2 deals with physical and physiological basics such as origination, propagation, and sensation of noise. The simple calculation with sound levels, representation of noise weighting, and evaluation criteria forms the basis of acoustic planning and implementation of effective noise protection (see Figure 1). The range of audibility to the human ear and the sensation and effect of different noise situations are shown in Figure 2.
Sound propagation in air, solids, and liquids—i.e., airborne, structure-borne, and water-borne sound—as well as description values for frequency, sound velocity, and wave length for sound events in these media are described in detail. Tables provide necessary material data and numerical values. Noise characteristics such as complex total sound, tone, and bang are comprehensively explained, as they are the basis of the physiological time, frequency, and nuisance weighting of noise. Explanations are provided for the following noise description values:
_ Sound pressure and sound pressure level
_ Sound velocity and sound velocity level
_ Sound intensity and sound intensity level
_ Sound power and sound power level
The connections between these values also are explained, as is the level arithmetic—i.e., adding, subtracting, and the space and time averaging of sound levels.
Document A3:
Product Characteristics—Acoustic Insulation, Absorption, Attenuation
Materials, their characteristics, and their acoustic effects are the subjects of Document A3. Acoustic insulation, attenuation (absorption) properties of materials, systems, and special constructions are presented and discussed. The international character of the FESI Acoustic Commission guarantees that products, systems, and materials common in Europe are considered. Sound insulation and sound attenuation of airborne and structure-borne sound, their measurement in the laboratory, and the handling of the single values Rw and R'w are comprehensively explained using figures and examples. Simple calculations for single systems (plane walls or pipes) enable rough estimation of the acoustic insulation of corresponding monolithic systems like brickwork, concrete walls and ceilings, or sheet-metal constructions. Weaknesses of material and system are taken into consideration. Information about “double systems” (basic walls with insulation) and absorbent insulations (suspended ceilings) is important for contractors in the room and building acoustics industry. The effects of materials and dimensions, resonances, and coupling of single layers with each other are described. Calculations and theoretical considerations are completed and supported by numerous measured values taken from standards, laboratory tests, and literature, providing a summary.
Document A4:
Acoustics in Buildings
Document A4 describes sound transmission in buildings, noise protection between rooms and against outdoor noise, as well as problems of ventilation and other operating noises. Consulting engineers and contractors get useful hints for the correct execution of noise-protection measures to avoid possible sources of defect and to determine the effectiveness of noise-control measures. One precondition for the design and dimensioning of noise protection with regard to building acoustics is knowledge of sound transmission paths (airborne, structure-borne, and impact sound). Document A4 gives examples for sound transmission between rooms through the building structure, as well as along and through technical devices (air conditioning). Simple calculation formulae and given loss factors are provided to enable users to estimate insulation and sound-improvement indices. Diagrams provide information about the influence of leak points such as venting slots and keyholes on the acoustic insulation of walls, doors, and enclosures. Examples of systems and comprehensive tables with insulation coefficients of approved constructions also are included. Tables with detailed information and classifications of door and window constructions relating to sound insulation provide useful tips.
Document A5:
Acoustics in Rooms
Apart from protection against noise, acoustics also involves communication and information so that people in a room can hear and understand what is being said. Document A5 describes acoustic characteristics of rooms and how to influence these characteristics. The document also explains the physical quantity “reverberation time T” as well as “indices for the determination of speech intelligibility:”
_ Articulation index (AI)
_ Sound interference level (SIL)
_ Percentage articulation loss of consonants (%ALCons)
_ Speech transmission index or rapid speech transmission index (STI, RASTI)
The validity of these quantities, correlations, and proportions, as well as numerous requirements and recommendations, facilitate the weighting of speech intelligibility in different rooms. Subjective factors such as distinctness, spaciousness, harmony, and steadiness also are discussed. Especially helpful is the table “Key parameters suggested for different types of rooms,” which states by which quantities different types of rooms must be weighted. Subsequent chapters of the document provide details for the treatment and furnishing of rooms. Simple calculations of sound propagation in rooms of different dimensions (cubic, flat, or long) are provided, along with comments regarding natural frequencies, sound diffusion, and acoustic phenomena like echoes/flutter echoes. Noise protection measures and their materials and position in the room are described so the best possible effect will be achieved.
Document A6:
Industrial Acoustics
As EU rules with regard to noise at the workplace and industrial plants’ effects on surrounding neighbourhoods have become stricter, Document A6 is of particular importance. Contractors get significant information on the sound and vibration effects of machines and plant components, sound propagation in workshops or toward adjacent residents, and the execution of effective sound protection. Materials, systems, their dimensioning and effect, sources of defects, and problematic situations are also discussed. Document A6 first deals with sound propagation in free field; in rooms; and in ducts, pipes, and air-conditioning systems. It explains how the distance between sound source and receiver, distribution of the radiated sound energy, acoustic insulation and attenuation on the propagation path, and additional noise sources disturb the “receiver”—e.g., at the workplace or in the neighbourhood of a plant. Simple calculations, tables with sound insulation and attenuation, and data of noise sources—e.g., in pipes and air-conditioning systems—enable estimation of disturbing noise and its reduction. A chapter on noise control discusses measures at the source or the point of origin, at the propagation path, and at the receiver corresponding to the model source, path, and receiver. Measures at the source and on the propagation path have first priority. The chapter describes the function and construction of silencers, sound hoods, and sound screens. Their effect can be estimated by a simple function, or it can be taken from corresponding tables. The effect of a sound hood is determined by:
_ Structure and weight per unit area of the hood wall
_ Portion of free openings in case of penetrations, or openings for material supply and removal, and
_ Possible vibration transmission by the foundation
Table 9, “Orienting construction characteristics for the enclosure groups,” lists examples and minimum requirements to comply with desired insertion losses. Users get the desired information at a glance without time-consuming calculations. Absorbent wall or ceiling linings prevent or reduce sound reflections without influencing the direct sound. The effect of this noise protection measure depends not only on the material and its dimensions, but also on the position with regard to noise source and receiver. A figure is provided illustrating such a situation (see Figure 3). The effect of the measure can be estimated with the corresponding functions.
Document A7:
Guidance through FESI Documents A2 through A6
Document A7, currently in progress, will be a reference for users of the other documents and includes all terms, rules, and body of directives. The chapter “Noise Control” references significant chapters of aforementioned acoustic documents, standards, and recommendations for further reading on dimension noise protection measures. The chapter “Measurements” describes how to prove the effectiveness of such measures, appropriate procedures and the use of the body of directives (regulations, standards, and recommendations) to determine sound emissions, as well as frequency dependent weighting and evaluation. In short, document A7 will provide a framework for acoustical design and problem solving.
Future Projects
Apart from completion of Document A7, the Acoustic Commission is dealing with the subject of acoustic comfort. The preparation of Document A5 with the acoustic evaluation of rooms according to their use (e.g., restaurants, classrooms, multi-purpose rooms) and terms like speech intelligibility and distinctness revealed that this subject has not been sufficiently considered in Europe. Thus, the Acoustic Commission first will verify the situation in Europe through use of a survey in the member countries, which will be supplemented by data of research and science, if necessary. Based on the results, recommendations will be given to standard organizations, working groups, and FESI members to enable them to design and implement noise protection measures. Documents A2 through A6 in English and the bilingual edition (German/English) can be downloaded from the FESI
website.
This article appeared in the December 2008 issue of Insulation Outlook.
Author Rennecke Hans-Joachim
Hans-Joachim Rennecke is Chairman of the FESI Acoustic Commission and Head of KAEFER Department Corporate Technology & Research/Acoustics at KAEFER Isoliertechnik GmbH & Co. KG. He has 30 years of experience with acoustic insulation in the fields of industry, shipbuilding, and room and building acoustics. He can be contacted at hj.rennecke@kaefer.com.
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http://www.fesi.eu/Page.aspx?pageType=NewsItem&pageID=270
Acoustic Solutions: A European Perspective
By Rennecke Hans-Joachim
Increasing population density and mobility, and mechanization of workplaces, households, and leisure activities, have resulted in increased general noise exposure for most people. The consequences for many are concentration and sleep disturbances, noise-induced hearing loss (noise deafness), and damage to the nervous system in the form of stomach, heart, and circulatory problems. According to statistics from the European Agency for Safety and Health at Work, approximately 22.5 million people in Europe suffered from hearing impairment due to noise in 2001, and about 2 million were considered extremely deaf. The costs of hearing impairment have been estimated at EUR 78 billion per year. Noise deafness is regarded as the most important and most recognized occupational disease, predominantly affecting men who work in manufacturing, construction, and transportation.
The general increase in exposure to noise has raised interest in the issue of noise protection and acoustic problems. The Acoustic Commission of the European Federation of Associations of Insulation Companies (Fédération Européenne des Syndicats d’ Entreprises d’Isolation—known as FESI) deals with these problems and assists its members with regard to acoustics and noise protection by providing information, including a series of six documents that address noise and noise protection. The documents can be used as a reference by planners, craftsmen, and contractors, but they are also applicable for training and studies. They provide detailed information about materials and systems and help users understand, evaluate, and solve acoustic problems. The idea behind the documents is to form a bridge between international directives and standards and practice-oriented application.
Document A2:
Basics of Acoustics
Acoustics is the science of sound and its influence on human beings. Document A2 deals with physical and physiological basics such as origination, propagation, and sensation of noise. The simple calculation with sound levels, representation of noise weighting, and evaluation criteria forms the basis of acoustic planning and implementation of effective noise protection (see Figure 1). The range of audibility to the human ear and the sensation and effect of different noise situations are shown in Figure 2.
Sound propagation in air, solids, and liquids—i.e., airborne, structure-borne, and water-borne sound—as well as description values for frequency, sound velocity, and wave length for sound events in these media are described in detail. Tables provide necessary material data and numerical values. Noise characteristics such as complex total sound, tone, and bang are comprehensively explained, as they are the basis of the physiological time, frequency, and nuisance weighting of noise. Explanations are provided for the following noise description values:
_ Sound pressure and sound pressure level
_ Sound velocity and sound velocity level
_ Sound intensity and sound intensity level
_ Sound power and sound power level
The connections between these values also are explained, as is the level arithmetic—i.e., adding, subtracting, and the space and time averaging of sound levels.
Document A3:
Product Characteristics—Acoustic Insulation, Absorption, Attenuation
Materials, their characteristics, and their acoustic effects are the subjects of Document A3. Acoustic insulation, attenuation (absorption) properties of materials, systems, and special constructions are presented and discussed. The international character of the FESI Acoustic Commission guarantees that products, systems, and materials common in Europe are considered. Sound insulation and sound attenuation of airborne and structure-borne sound, their measurement in the laboratory, and the handling of the single values Rw and R'w are comprehensively explained using figures and examples. Simple calculations for single systems (plane walls or pipes) enable rough estimation of the acoustic insulation of corresponding monolithic systems like brickwork, concrete walls and ceilings, or sheet-metal constructions. Weaknesses of material and system are taken into consideration. Information about “double systems” (basic walls with insulation) and absorbent insulations (suspended ceilings) is important for contractors in the room and building acoustics industry. The effects of materials and dimensions, resonances, and coupling of single layers with each other are described. Calculations and theoretical considerations are completed and supported by numerous measured values taken from standards, laboratory tests, and literature, providing a summary.
Document A4:
Acoustics in Buildings
Document A4 describes sound transmission in buildings, noise protection between rooms and against outdoor noise, as well as problems of ventilation and other operating noises. Consulting engineers and contractors get useful hints for the correct execution of noise-protection measures to avoid possible sources of defect and to determine the effectiveness of noise-control measures. One precondition for the design and dimensioning of noise protection with regard to building acoustics is knowledge of sound transmission paths (airborne, structure-borne, and impact sound). Document A4 gives examples for sound transmission between rooms through the building structure, as well as along and through technical devices (air conditioning). Simple calculation formulae and given loss factors are provided to enable users to estimate insulation and sound-improvement indices. Diagrams provide information about the influence of leak points such as venting slots and keyholes on the acoustic insulation of walls, doors, and enclosures. Examples of systems and comprehensive tables with insulation coefficients of approved constructions also are included. Tables with detailed information and classifications of door and window constructions relating to sound insulation provide useful tips.
Document A5:
Acoustics in Rooms
Apart from protection against noise, acoustics also involves communication and information so that people in a room can hear and understand what is being said. Document A5 describes acoustic characteristics of rooms and how to influence these characteristics. The document also explains the physical quantity “reverberation time T” as well as “indices for the determination of speech intelligibility:”
_ Articulation index (AI)
_ Sound interference level (SIL)
_ Percentage articulation loss of consonants (%ALCons)
_ Speech transmission index or rapid speech transmission index (STI, RASTI)
The validity of these quantities, correlations, and proportions, as well as numerous requirements and recommendations, facilitate the weighting of speech intelligibility in different rooms. Subjective factors such as distinctness, spaciousness, harmony, and steadiness also are discussed. Especially helpful is the table “Key parameters suggested for different types of rooms,” which states by which quantities different types of rooms must be weighted. Subsequent chapters of the document provide details for the treatment and furnishing of rooms. Simple calculations of sound propagation in rooms of different dimensions (cubic, flat, or long) are provided, along with comments regarding natural frequencies, sound diffusion, and acoustic phenomena like echoes/flutter echoes. Noise protection measures and their materials and position in the room are described so the best possible effect will be achieved.
Document A6:
Industrial Acoustics
As EU rules with regard to noise at the workplace and industrial plants’ effects on surrounding neighbourhoods have become stricter, Document A6 is of particular importance. Contractors get significant information on the sound and vibration effects of machines and plant components, sound propagation in workshops or toward adjacent residents, and the execution of effective sound protection. Materials, systems, their dimensioning and effect, sources of defects, and problematic situations are also discussed. Document A6 first deals with sound propagation in free field; in rooms; and in ducts, pipes, and air-conditioning systems. It explains how the distance between sound source and receiver, distribution of the radiated sound energy, acoustic insulation and attenuation on the propagation path, and additional noise sources disturb the “receiver”—e.g., at the workplace or in the neighbourhood of a plant. Simple calculations, tables with sound insulation and attenuation, and data of noise sources—e.g., in pipes and air-conditioning systems—enable estimation of disturbing noise and its reduction. A chapter on noise control discusses measures at the source or the point of origin, at the propagation path, and at the receiver corresponding to the model source, path, and receiver. Measures at the source and on the propagation path have first priority. The chapter describes the function and construction of silencers, sound hoods, and sound screens. Their effect can be estimated by a simple function, or it can be taken from corresponding tables. The effect of a sound hood is determined by:
_ Structure and weight per unit area of the hood wall
_ Portion of free openings in case of penetrations, or openings for material supply and removal, and
_ Possible vibration transmission by the foundation
Table 9, “Orienting construction characteristics for the enclosure groups,” lists examples and minimum requirements to comply with desired insertion losses. Users get the desired information at a glance without time-consuming calculations. Absorbent wall or ceiling linings prevent or reduce sound reflections without influencing the direct sound. The effect of this noise protection measure depends not only on the material and its dimensions, but also on the position with regard to noise source and receiver. A figure is provided illustrating such a situation (see Figure 3). The effect of the measure can be estimated with the corresponding functions.
Document A7:
Guidance through FESI Documents A2 through A6
Document A7, currently in progress, will be a reference for users of the other documents and includes all terms, rules, and body of directives. The chapter “Noise Control” references significant chapters of aforementioned acoustic documents, standards, and recommendations for further reading on dimension noise protection measures. The chapter “Measurements” describes how to prove the effectiveness of such measures, appropriate procedures and the use of the body of directives (regulations, standards, and recommendations) to determine sound emissions, as well as frequency dependent weighting and evaluation. In short, document A7 will provide a framework for acoustical design and problem solving.
Future Projects
Apart from completion of Document A7, the Acoustic Commission is dealing with the subject of acoustic comfort. The preparation of Document A5 with the acoustic evaluation of rooms according to their use (e.g., restaurants, classrooms, multi-purpose rooms) and terms like speech intelligibility and distinctness revealed that this subject has not been sufficiently considered in Europe. Thus, the Acoustic Commission first will verify the situation in Europe through use of a survey in the member countries, which will be supplemented by data of research and science, if necessary. Based on the results, recommendations will be given to standard organizations, working groups, and FESI members to enable them to design and implement noise protection measures. Documents A2 through A6 in English and the bilingual edition (German/English) can be downloaded from the FESI
website.
This article appeared in the December 2008 issue of Insulation Outlook.
Author Rennecke Hans-Joachim
Hans-Joachim Rennecke is Chairman of the FESI Acoustic Commission and Head of KAEFER Department Corporate Technology & Research/Acoustics at KAEFER Isoliertechnik GmbH & Co. KG. He has 30 years of experience with acoustic insulation in the fields of industry, shipbuilding, and room and building acoustics. He can be contacted at hj.rennecke@kaefer.com.
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FESI thermal insulation technical article : Very good
วันศุกร์ที่ 4 ธันวาคม พ.ศ. 2552
PTT's plan with projects
PTT suspends merger plans Group awaits outcome of Map Ta Phut case A planned merger of four PTT Group petrochemical and refining units has been delayed pending a court settlement on the ongoing Map Ta Phut dispute, a senior executive says. The merger has been delayed until the court outlines clear environmental enforcement guidelines for 76 suspended industrial projects, worth about 400 billion baht, in Rayong’s Map Ta Phut Industrial Estate, said Prajya Phinyawat, chief operating officer of PTT’s downstream petroleum business group. Of the 76 suspended projects, 25 ventures, worth about 130 billion baht in total, belong to PTT and its affiliates. PTT has been studying the possible merger of PTT Chemical Plc (PTTCH), IRPC Plc, PTT Aromatics and Aromatics and Refining Plc (PTTAR) and Thai Oil Plc (TOP). The plan, which was originally to be finalised in October, was pushed back to the year-end. But Mr Prajya said the merger would now not be concluded until the court sets clear compliance guidelines for the projects. “How can we decide which formula is most suitable for the merger until we know what is going to happen with their operations [once the verdict is made]?” he said yesterday. “The merger will proceed immediately after we know what we have to do to comply with the court’s order.” PTTCH, meanwhile, has been in talks to acquire petrochemical projects in neighbouring countries, said president and CEO Veerasak Kositpaisal. Negotiations with petrochemical manufacturers in Southeast Asia are expected to conclude next year. The company has the capacity to raise up to 60 billion baht in funds to finance investments over the next five years, he said. Asean will integrate into a single production base by eliminating tariffs on petrochemical products traded within the region next year. Asean market integration will pave the way for better access for PTTCH products to markets such as Indonesia, the Philippines, Malaysia and Vietnam. Mr Veerasak said acquiring existing assets in Asean was appropriate for PTTCH to integrate its operations as key petrochemical products are expected to swell when new capacity, mainly from the Middle East and China, come online starting next year. At the same time, PTTCH has prepared a contingency plan in case PTT’s sixth gas-separation plant – one of the suspended projects in Map Ta Phut – has to be delayed beyond its scheduled operational target of the first quarter next year. The $780-million gas-separation plant is considered vital to the operation of PTTCH’s cracker plant which is targeted to start commissioning in late December, he said. PTT’s chief financial officer Tevin Vongvanich said if, in the worst case, the sixth gas plant cannot proceed, 300 million cubic feet per day of local supply will evaporate, forcing Thailand to import more liquefied petroleum gas. PTT projects crude oil price to move in a range of $65 to $75 per barrel in the final quarter, with Dubai crude now trading above $70, he said. The gross refining margin is expected to edge down from $1.70 a barrel in the third quarter while petrochemical prices will also weaken. “Fortunately, the spread margin has declined less than we anticipated while the demand has improved in line with the global economy,” he said. Consequently, PTT is likely to report better-than-expected profit this year, possibly higher than the 51.7 billion baht posted in 2008, but total revenue will fall below last year’s 2 trillion baht. Shares of PTT closed yesterday on the Stock Exchange of Thailand at 233 baht, down six baht, in trade worth 1.03 billion baht. PTTCH declined 1.25 baht to 70.75, in turnover worth 206.4 million baht. ฺํBY Bangkok Post 20/11/09
76 projects in Map Ta Phut with insulations
โครงการที่ ผ่านให้มีการ ทำงานต่อไปได้
1. Clean energy and product quality enhancement/Rayong Refinery
2. Gas recycling enhancement/HMC Polymers
3. Clean energy, oil vapour controlling unit installation/Star Petroleum Refining
4. Oil vapour controlling unit installation/PTT Aromatics and Refining
5. Air pollution improvement/Indorama Petroleum
6. Wastewater treatment improvement/PTT
7. Chlorine vaporiser and wet scrubber installation/Aditya Berla Chemicals (Thailand)
8. Tank relocation/Map t Tank Terminal
9. LPG/Brutene Depot-Wharf/PTT Chemical
10. Loading Arm Installation/Star Petroleum Refining
11. Petrochemical Depot-Wharf/Map Ta Phut Tank Terminal
1. Clean energy and product quality enhancement/Rayong Refinery
2. Gas recycling enhancement/HMC Polymers
3. Clean energy, oil vapour controlling unit installation/Star Petroleum Refining
4. Oil vapour controlling unit installation/PTT Aromatics and Refining
5. Air pollution improvement/Indorama Petroleum
6. Wastewater treatment improvement/PTT
7. Chlorine vaporiser and wet scrubber installation/Aditya Berla Chemicals (Thailand)
8. Tank relocation/Map t Tank Terminal
9. LPG/Brutene Depot-Wharf/PTT Chemical
10. Loading Arm Installation/Star Petroleum Refining
11. Petrochemical Depot-Wharf/Map Ta Phut Tank Terminal
วันเสาร์ที่ 12 กันยายน พ.ศ. 2552
การออกแบบกล่องคลอบเสียงขนาดใหญ่ (Large Acoustic Enclosure)
กล่องครอบลดเสียงขนาดใหญ่ (Large Acoustic Enclosure) ที่มีฉนวนซับเสียง (Sound-Absorbing) ภายใน
กล่องครอบลดเสียง ถูกนำมาใช้เมื่อขนาดของผนังของกล่องครอบ และ ปริมาตรของกล่องมีค่า resonant modes สูง ในช่วงคลื่นความถี่ที่สูง และวิธีการทางสถิติ ในการทำนายระดับเสียงภายใน และการสั่นสะเทือน และเสียงที่ดังออกมาจากผนังของกล่อง กล่องครบลดเสียงขนาดใหญ่นี้มักนำมาใช้ในการลดเสียงในอุตสาหกรรม ที่มีการส่งผ่านพลังงานเสียงได้หลายทาง ดังภาพที่ 1 โดยเสียงที่สามารถดังผ่านเส้นทางหลายทาง ได้แก่ (1) เสียงดังผ่านผนังของกล่องครอบลดเสียง (2) เสียงรั่วผ่านจุดเปิด (3) เสียงดังผ่านโครงสร้าง (structure-borne)
เสียงดังกลุ่มที่ 1 เป็นเสียงที่ดังผ่านผนังเกิดจากเสียงที่ดังมาจากการกระตุ้นของพลังงานเสียงภายในกล่องผ่านทางผนังของกล่องครอบเสียง ทำให้เกิ
ดเสียงดังกระจายออกมาจากผนังของกล่องครอบ เสียงที่ดังผ่านมาในลักษณะนี้เป็นที่เข้าใจ และสามารถ
ทำนายระดับเสียงที่ดังออกมาได้อย่างถูกต้องตามหลักวิศวกรรม
เสียงดังในกลุ่มที่ 2 เสียงที่ดังผ่านรูรั่ว
หรือช่องเปิดของกล่องครอบ เช่น ช่องเปิด หรือท่อระบายอากาศภายใน หรือช่องระหว่างประเก็นกันอากาศรั่ว
ของกล่องครอบ พื้น หรือ ประตูเปิดของกล่อง ซึ่งระดับเสียงจากการดังผ่านช่องเปิดเหล่านี้ ได้มีการศึกษา
และเป็นที่เข้าใจได้บ้าง แต่เป็นสิ่งที่ควบคุมได้ยาก
ส่วนเสียงที่ดังกลุ่มที่ 3 เป็น
เสียงที่ดังโดยการกระจายผ่านพื้นผิวที่เป็นของแข็งที่เชื่อมต่อกับอุปกรณ์ที่สั่นสะเทือนภายในกล่องครอบ
แกน หรือ ท่อที่เจาะผ่านผนังของกล่องครอบลดเสียง หรือการสั่นสะเทือนของพื้นที่ไม่ได้ถูกกล่องครอบไว้ การลด
เสียงในกลุ่มนี้ยากที่จะทำนายถ้าไม่มีข้อมูลโดยละเอียดเกี่ยวกับการเคลื่อนที่ของเครื่องจักรที่มีการสั่นสะเทือนอยู่ตลอดเวลา ความพยายามที่จะลดเ
สียง ต้องเป็นผลจากการกันไม่ให้มีการเชื่อมต่อของโครงสร้าง หรือของแข็ง
ในการออกแบบ กล่องครอบลดเสียง
ควรมีการควบคุมเสียงที่ดังผ่านเส้นทางต่างๆ ดังที่กล่าวมานี้
การวิเคราะห์รูปแบบการทำนายเสียงที่ลดลงในคลื่นความถี่สูง
แหล่งกำเนิดที่อยู่ในกล่องค
รอบลดเสียงขนาดใหญ่ จะกระจายเสียงในระดับเดียวกันกับเมื่อแหล่งกำเนิดนั้นไม่มีกล่องครอบลดเสียงอยู่ เ
พื่อให้สามารถทำให้เสียงลดลงได้ในระดับมากๆ ต้องมีการหน่วง (dissipate) พลังงานเสียงในเปอร์เซ็นที่สูงใ
ห้กลายเป็นพลังงานความร้อนภายในกล่องครอบลดเสียงอย่างถูกต้อง
การทำนายระดับเสียงที่ลดลงภายใน
กล่องครอบเสียงขนาดใหญ่ โดยการคำนวณหาค่า Sound transmission ของกล่องครอบที่ผ่านผนัง (WTW) , ค่า Sound transmission ที่ผ่าน silencer (WTS) ,
ค่า Sound Transmission ที่ผ่านช่องเปิดต่างๆ (WTG) และค่า Sound Transmission ผ่านโครงสร้าง Structure borne (WSB)โดยเราสามารถประมาณค่า insertio
n loss ของกล่องครอบได้ตามสมการนี้
IL ≡ 10 log Wo/[WTW + WTG+ WTS + WSB] dB [1]
ถ้าเราสามารถออกแบบให้ก
ารลดเสียงผ่านผนังของกล่องครอบ และ silencer ได้ดีสามารถยุบค่าในสมการที่ [1] ได้ดังนี้
IL ≈ Rw + 10log (A/Sw) dB [2]
เมื่อ A = (Swαw + Siαi) โดยสมการจะใช้ได้ดีเมื่อค่าสัมประสิทธิ์ การดูดกลืน
เสียงของ lining (αw ≈ 1)
Sw = Total interior wall surface
Siαi = total absorption in the interior in excess of the wall absorption (i.e. machine body itself)
มีหลายปัจจัยที่ส่งผลต่อ insertion loss ของกล่อง
ครอบลดเสียงได้แก่
- Absorption coefficient ของ lining (α) ค่า IL จะเพิ่มขึ้น ถ้า ดูดกลืนจากการสะท้อนของเสียงมี มากขึ้น
- ระยะทางระหว่างเครื่องจักร ถึงผนังของกล่อง ถ้าระยะทาง d ลดลง มากกว่า ค่าวิกฤต IL จะลดลง ที่ช่วงคลื่นความถี่ต่ำ
- ความหนาของผนังข องกล่องเพิ่มขึ้น ค่า IL จะเพิ่มขึ้น
- ความหนาแน่นของผนัง (ρM) เพิ่มขึ้น ค่า IL จะเพิ่มขึ้น
- ความเร็วของคลื่นในทิศทางตาม longitudinal ของ ผนัง CL =
ทำให้ค่า IL ลดลงที่ช่วงคลื่นความถี่ต่ำกว่า critical frequency (fc) - ค่า critical frequency (fc) ของผนัง fc = c2/1.8CLh ถ้า fc สูงขึ้นต่อความหนาแน่นของผนัง ค่า IL จะเพิ่มขึ้น
- การกระจายเสียงของผนัง เพิ่มขึ้นทั้งภายใน (αi) และภายนอก (αo) ทำให้ค่า IL ลดลง
- ความกระด้าง และแข็งตัวของผนัง (stiffness) ทำให้ ค่า IL ลดลง
- รูรั่วที่มากขึ้น ย่อมเป็นผลทำให้ IL ลดลง จึงต้องให้ความระมัดระวัง ในการออกแบบรอยต่อต่างๆ ที่เป็นของแข็ง
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