Mechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the design, production, and operation of machines and tools.[1] It is one of the oldest and broadest engineering disciplines.
The engineering field requires a vast understanding of core concepts including mechanics, kinematics, thermodynamics, materials science, and structural analysis. Mechanical engineers use these core principles along with tools like computer-aided engineering and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, motorized vehicles, aircraft, watercraft, robotics, medical devices and more.
這一篇是對(duì)機(jī)械工程的簡(jiǎn)單介紹
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'China threat' theory is absurd As the sleeping dragon awoke toward the end of the last century, the West felt uneasy. And when it took off on the road to rapid economic development, the West's unease began turning into fear, giving rise to the "China threat" theory which is bandied about so rampantly across the world todayIs their any justification behind this theory? In short, my answer is "no". But I prefer to delve deep into the reasons behind, what I am concern is, the unjustified fear gripping the West. Some people try to attribute the country's economic rise to "China's development model", I think, building an insurmountable barrier between the East and West, between antiquity and modernity. "China is just regaining its long lost right to have its say in world affairs. Harmonious coexistence of countries entails diverse views, not a hegemonic monopoly which presumptuously claims to speak for all the countries." The fact is that the Chinese leadership has too many domestic problems to solve and doesn't have the time to pose a threat to other countries or regions. Historically, the rise of a country has created controversies and raised the concern of its neighbors and, above all, the existing powers. It's natural for the West to nurse such views as the "China threat" theory. But it shouldn't deny China from having its say. Chinese people can have their say by solving their problems, building the country's image and ridding the rest of the world of its misunderstanding and prejudice against China through their actions. Among those actions, transparency takes the top spot. The West has long based its "China threat" theory on the blown-up image of the country's economic success presented by the Chinese media. The Chinese media may be over-enthusiastic but since ancient times, Chinese politicians have considered economic growth as the best justification for being in power. The Chinese government's goal is to build a harmonious society not only in the country, but also across the world. A harmonious society, however, is by no means a system dominated by one single thought, rather it is more of a system based on diverse thoughts, the best of which are combined to bring the maximum benefit to the country and its people. It is to be understood that covering our drawbacks will intensify the tensions in the social system. This could create an obscure image of China, which would give the West enough room to indulge in rumor-mongering. The government should have the confidence to face up to the problems that its fast paced economic development has created, I think. "Western countries had enough time and space to transform their economic structures. As a result, the advantages they still enjoy in many fields have resulted in much of the ills afflicting the developing world. The West transfers only the lower links of its industrial chain to the developing countries, which carries with it pollution and social costs. How in the world then can the West be justified in accusing China of posing a threat, especially when the Chinese government's only goal is to improve the livelihood of its people?" Let one thing be clear, China does not enjoy the luxury of time to lift millions of its people out of poverty and transform its economic structure. That is to say China cannot afford to follow in the footsteps of the West, although it is interacting with the rest of the world to explore how things can be best turned around. As American writer Owen Lattimore put it, China's history is actually a process of cultural communication between nomadic and farming civilizations across the Great Wall, the Yellow River and even the Yangtze River. Thus China's development model has never been static. So there cannot be a "China development model". If there is any, it is a dynamic, ever-changing model characterized by frequent exchanges of commodities and, to a lesser extent, cultures. I hold the thought that the government needs to portray the country as a cultural being and depoliticize its story-telling style. But, many people argue, how can the government do that when Chinese culture is highly influenced by foreign cultures? I don't share the view of the skeptics. In my opinion cultural exchange and mutual influence take a long time to bring about changes. So, it's naive to predict the downfall of Chinese culture and to deny its dynamic nature. The problems that the early stages of the cultural industry's commercialization face do not necessarily endanger the cultural heritage of a country. Instead, a deep understanding of Western cultural industry would not only help make the Chinese media 。
Crane Work Needs More Technique Abstract Crane work needs more technology. Construction of tower cranes are the main vertical transportation equipment and also a measure of construction companies and equipment strength of the important logo, in today's increasingly competitive construction market, to meet the construction needs of many construction companies have bought the tower crane. With the tower crane at the construction site of the widely used by the tower crane accident also caused more and more to people's lives and property brought about great losses. According to national statistics, the departments concerned, the tower crane accident rate reached 2.77 percent. Its security problem is still the urgency of the construction Loose training, testing and oversight requirements for the people who work around construction cranes have fostered a false sense of security in our industry. The recent deadly tower-crane collapse at a congested New York City building site should be a wake-up call for us to question and step up our current safety practices.Training and testing is king when it comes to safety. But the construction industry is putting unqualified personnel in the seats of construction cranes, even with today's testing. In many places, no experience is necessary after passing a standardized test. One week of study will give some people enough knowledge to pass a certification examination, and then they can jump into the cab of a crane.Imagine that a commercial airline pilot had the same training as a certified crane operator. How would you feel the next time you decided to fly? In California, it takes more hours of training to wield a pair of scissors in a hair salon than to operate potentially dangerous lifting machinery. How does this make sense?Riggers and signal persons also need standard training and testing to ensure safety under the hook. Employers usually allow any craft to signal a crane on a jobsite, despite best practices that require only qualified people do so. How is it then that uncertified and untrained people are allowed to signal and rig under the hook of a licensed or certified operator?Tower cranes are particularly risky as urban sites become more congested, and the risk of a catastrophic event is very high during climbing operations. Yet most tower-crane climbing crews are trained in a non-traditional manner, via secondhand knowledge that has been passed down over time. The problem with this type of hand-me-down knowledge is that it changes over the years, leaving out small-but-important details along the way. This "osmosis" of knowledge leads crews to develop their own tricks for climbing cranes, often forsaking basic safety in an attempt to save time and energy.In many cases, there are no safety devices or alarms to warn of a serious problem. Climbing crews are subjected to pressures that affect safety-critical decision-making. It is not uncommon for climbs to continue with damaged or leaking hydraulic systems, out-of-adjustment or jammed guide rollers, often working in the dark and for extended hours. This "MacGyver" method of climbing, where every jump becomes a new adventure, should not be the norm.Climbing-frame designs vary among manufacturers, but the operational steps are similar in principle. The climbing process is relatively straightforward, with a mixture of physical work and technical procedure. It is not complex; it is more about knowing the proper sequence of what needs to be done and then following the steps, one by one, making sure each step has been successfully completed before moving onto the next. It is essential that everyone know exactly what is going on and what the dangers are at every stage.That's why the industry needs standardized training, testing and oversight for this work, including a practical assessment of competence. Technicians should have model-specific training directly from the manufacturer, along with a level of practical experience. Inspectors, too, should be required to have specific technical training. They should be independent from all aspects of installation and maintenance to allow for objective decisions. Key personnel on erection crews should have standard training and testing.When these needs are satisfied, crane operations should be carried out in strict accordance with the manufacturers' instructions, engineering principals and governmental laws. But industry stakeholders and lawmakers need to step up their lax standards to protect the public. New York City residents, who have seen their homes turned into dust and debris, would be shocked at the way the 。
Three crossflow (No.1-No.3) dryers were tested. Dyer No.1 contains two crossflow columns, each column consists of two drying sections, one turn-flow device and a cooling section, and with a grain column thickness in the upper drying section of 0.277m and 0.304m in the lower section. The dimensions of dryer No.1 are 6.517m*3.400m*13.482m. No.2 dryer is similar to No.1, but is smaller and has a lower capacity. No.3 is a cylindrical crossflow dryer with two drying sections, one turn-flow device and a cooling section. The mixed-flow dryer (No.4) is composed of eight modular sections. Each module has dimensions of 1.8m*1.0m*0.8m. The tow bottom modules serve as cooling stage. Dryer No.5 consists of two mixed-flow drying towers in series, similar in design as dryer No.4. Dryers No.6-No.10 are concurrent-/counter-flow dryers, consisting of two or more towers. The number in front of “-CCF” indicates the number of towers. Each tower has two counter-/concurrent-flow drying sections. The last tower, or part of the last tower, is used for cooling. The depth of the counter-/concurrent-flow beds is 0.6m, the cross-sectional area of each tower is 2.2m*2.2m. It should be noted that overseas CCF dryers do not have counter-flow drying stages, only a counter-flow cooling stage. The steam dryer is a unique dryer widely used in grain depots in China. It consists of 3-6 indoor drying and cooling towers, and a boiler. Each tower contains in its upper section a series of steam pipes, and in its lower section a number of inlet/outlet air ducts. The grain is heated by conduction as it flow over the steam-heated pipes, and is subsequently treated with ambient or slightly-heated recycled drying-air. The steam pressure in the pipes is 2*105Pa--4*105Pa (130-140℃), the diameter of the pipes is 42-48mm, and the distance between pipes is 110-120mm. The grain retention time is long (4-6 hours for 10-point moisture removal) due to the relatively low grain temperature. Sun drying is still the main method of grain drying in China. Almost every village or depot has a special area for the sun drying of grains. The grain is spread out in 5-10cm thin layer and is stirred occasionally. In Northeast China where the ambient temperature is very low when maize is harvested, sun drying is a very slow process.三橫(一號(hào)至三號(hào))烘干設(shè)備進(jìn)行了測(cè)試. 戴先生no.1包含兩個(gè)橫欄,每欄分為兩部分干燥, 一轉(zhuǎn)流器及冷卻段, 與糧食柱厚度在上部干燥部分0.277m和0.304m在下游. 尺寸干燥器一號(hào)是6.517m*3.400m*13.482m. 二號(hào)烘干機(jī)相似一號(hào),但規(guī)模較小,具有容量較低. 第三是橫向圓筒烘干機(jī)烘干兩部分,一部分是轉(zhuǎn)流裝置和冷卻段. 混流式干燥機(jī)(四號(hào))是由八個(gè)單元章節(jié). 每個(gè)單元尺寸1.8*1.0*0.8米. 拖車(chē)底部模塊作為冷卻階段. 干燥器no.5分為兩個(gè)混流干燥塔系列,類(lèi)似的設(shè)計(jì)作為烘干四號(hào). 干衣no.6-no.10都是concurrent-/counter-flow烘干機(jī),由兩個(gè)或兩個(gè)以上的彈孔. 數(shù)年前的"框架",表明了很多水塔. 每個(gè)塔有兩個(gè)counter-/concurrent-flow曬路段. 最后塔,或部分上塔,是用于冷卻. 有深度的counter-/concurrent-flow病床0.6m,橫截面的每個(gè)塔有2.2m*2.2m. 應(yīng)當(dāng)指出,海外ccf干衣沒(méi)有反流干燥階段,只有一個(gè)反流冷卻階段. 蒸氣烘干是一個(gè)獨(dú)特的烘干機(jī)廣泛用于糧庫(kù)中. 它由3-6室內(nèi)干燥,冷卻水塔,一臺(tái)鍋爐. 每個(gè)塔載在其上部一系列的蒸汽管道, 而在其下游的一系列進(jìn)/出水口風(fēng)筒. 谷物的熱傳導(dǎo),因?yàn)樗髁苏羝訜峁埽?并隨后處理空氣或微循環(huán)加熱干燥的空氣. 蒸汽壓力管道2*105pa--4*105pa(130-140℃),直徑較小的管材是42-48mm, 之間的距離和管道是110-120mm. 糧食停留時(shí)間很長(zhǎng)(4-6小時(shí),10點(diǎn)去濕)由于相對(duì)較低的糧食溫度. 晾曬仍然是主要的方法谷物干燥中. 幾乎每一個(gè)村或倉(cāng)庫(kù)具有特殊的地區(qū),以供晾曬谷物. 糧食是分布在5-10cm薄層,偶爾攪拌. 在東北那里的氣溫很低,當(dāng)玉米收割, 太陽(yáng)曬是一個(gè)非常緩慢的過(guò)程。
Assembly line組裝線 Layout布置圖 Conveyer流水線物料板 Rivet table拉釘機(jī) Rivet gun拉釘槍 Screw driver起子 Electric screw driver電動(dòng)起子 Pneumatic screw driver氣動(dòng)起子 worktable 工作桌 OOBA開(kāi)箱檢查 Out of Box Auditfit together組裝在一起 fasten鎖緊(螺絲) fixture 夾具(治具) pallet棧板 barcode條碼 barcode scanner條碼掃描器 fuse together熔合 fuse machine熱熔機(jī) repair修理 operator作業(yè)員 QC品管 supervisor 課長(zhǎng) ME制造工程師 MT制造生技 cosmetic inspect外觀檢查 inner parts inspect內(nèi)部檢查 thumb screw大頭螺絲 lbs. inch鎊、英寸 EMI gasket導(dǎo)電條 front plate前板 rear plate后板 chassis 基座 bezel panel面板 power button電源按鍵 reset button重置鍵 Hi-pot test of SPS高源高壓測(cè)試 Voltage switch of SPS 電源電壓接拉鍵 sheet metal parts 沖件 plastic parts塑膠件 SOP制造作業(yè)程序 material check list物料檢查表 work cell工作間 trolley臺(tái)車(chē) carton紙箱 sub-line支線 left fork叉車(chē) personnel resource department 人力資源部 production department生產(chǎn)部門(mén) planning department企劃部 QC Section品管科 stamping factory沖壓廠 painting factory烤漆廠 molding factory成型廠 common equipment常用設(shè)備 uncoiler and straightener整平機(jī) punching machine 沖床 robot機(jī)械手 hydraulic machine油壓機(jī) lathe車(chē)床 |刨床?planer |'plein miller銑床 grinder磨床 driller鉆床 linear cutting線切割 electrical sparkle電火花 welder電焊機(jī) staker=reviting machine鉚合機(jī) position職務(wù) president董事長(zhǎng) general manager總經(jīng)理 special assistant manager特助 factory director廠長(zhǎng) department director部長(zhǎng) deputy manager | =vice manager副理 section supervisor課長(zhǎng) deputy section supervisor =vice section supervisor副課長(zhǎng) group leader/supervisor組長(zhǎng) line supervisor線長(zhǎng) assistant manager助理 to move, to carry, to handle搬運(yùn) be put in storage入庫(kù) pack packing包裝 to apply oil擦油 to file burr 銼毛刺 final inspection終檢 to connect material接料 to reverse material 翻料 wet station沾濕臺(tái) Tiana天那水 cleaning cloth抹布 to load material上料 to unload material卸料 to return material/stock to退料 scraped |'skr?pid|報(bào)廢 scrape ..v.刮;削 deficient purchase來(lái)料不良 manufacture procedure制程 deficient manufacturing procedure制程不良 n|氧化?oxidation |' ksi'dei scratch刮傷 dents壓痕 defective upsiding down抽芽不良 defective to staking鉚合不良 embedded lump鑲塊 feeding is not in place送料不到位 stamping-missing漏沖 production capacity生產(chǎn)力 education and training教育與訓(xùn)練 proposal improvement提案改善 spare parts=buffer備件 forklift叉車(chē) trailer=long vehicle拖板車(chē) compound die合模 die locker鎖模器 pressure plate=plate pinch壓板 bolt螺栓 name of a department部門(mén)名稱 administration/general affairs dept總務(wù)部 automatic screwdriver電動(dòng)啟子 thickness gauge厚薄規(guī) gauge(or jig)治具 power wire電源線 buzzle蜂鳴器 defective product label不良標(biāo)簽 identifying sheet list標(biāo)示單 screwdriver holder起子插座 pedal踩踏板 stopper阻擋器 flow board流水板 hydraulic handjack油壓板車(chē) forklift叉車(chē) pallet棧板 glove(s)手套 glove(s) with exposed fingers割手套 thumb大拇指 forefinger食指 midfinger中指 ring finger無(wú)名指 little finger小指 band-aid創(chuàng)可貼 iudustrial alcohol工業(yè)酒精 alcohol container沾濕臺(tái) head of screwdriver起子頭 sweeper掃把 mop拖把 vaccum cleaner吸塵器 rag 抹布 garbage container灰箕 garbage can垃圾箱 garbage bag垃圾袋 chain鏈條 jack升降機(jī) production line流水線 chain鏈條槽 magnetizer加磁器 lamp holder燈架 to mop the floor拖地 to clean the floor掃地 to clean a table擦桌子 air pipe 氣管 packaging tool打包機(jī) packaging打包 missing part漏件 wrong part錯(cuò)件 excessive defects過(guò)多的缺陷 critical defect極嚴(yán)重缺陷 major defect主要缺陷 minor defect次要缺陷 not up to standard不合規(guī)格 dimension/size is a little bigger尺寸偏大(?。?cosmetic defect外觀不良 slipped screwhead/slippery screw head螺絲滑頭 slipped screwhead/shippery screw thread滑手 speckle斑點(diǎn) mildewed=moldy=mouldy發(fā)霉 rust生銹 deformation變形 burr(金屬)flash(塑件)毛邊 poor staking鉚合不良 excesssive gap間隙過(guò)大 grease/oil stains油污 inclusion雜質(zhì) painting peel off臟污 shrinking/shrinkage縮水 mixed color雜色 scratch劃傷 poor processing 制程不良 poor incoming part事件不良 fold of packaging belt打包帶折皺 painting make-up補(bǔ)漆 discoloration羿色 water spots水漬 polishing/surface processing表面處理 exposed metal/bare metal金屬裸露 lack of painting烤漆不到位 safety安全 quality品質(zhì) delivery deadline交貨期 cost成本 engineering工程 die repair模修 enterprise plan = enterprise expansion projects企劃 QC品管 die worker模工 production, to produce生產(chǎn) equipment設(shè)備 to start a press開(kāi)機(jī) stop/switch off a press關(guān)機(jī) classification整理 。
c Along with the development of economics, the increment of population, and the improvement of traffic conditions automotives have been used widely, its number increasing year after year. Then developing perfect vehicle's transmission system is becoming more and more urgent. Compared with conventional multiratio gearbox, the metal V-belt 無(wú)效 continuously Variable Transmissions have attracted a great deal of interest because of their economy, drive performance and comfort. Now many big motor corporations all over the world are investing huge money to investigate them. In this thesis, its history, current status, and the dimension parameters and function of principal structures are described. Through the analysis of its working progress, the author explained the superiority and advantage of this device. For the metal V-belt CVT, the belt transmission device is the hardcore, and one of its key parts is the pulley. It affects the transmissionquality, the efficiency and the life and cost of the CVT. To straight generatrix pulleys, while the transmission ratio isn't one to one, the matal belt will retort, resulting in the declining of the belt's life. In this thesis, the reason of retorting and the relation between the deflection and transmission ratio are analyzed. The author tesified that the pulley's genetrix shouldn't be straight if there is no deflection happening. The object of this thesis is to design the curve genetrix to meet requirements. Defining the mesh point between metal block and pulley as the initial point, the surface within the initial point as the inner prick, the surface outside the initial point as the outer one. Analyzing the relative movement between pulleys and metal blocks separately to acquire their onnection formula. Only when the numerical values meet this formula won't the metal V-belt deflect. From the connection formula between pulleys and metal blocks, we know the genetrix which meet the formula is not one and only. Considering the contact stress between pulleys and metal blocks affect carrying capacity of the CVT, the author tried to choose one genetrix which can reduce the stress to the minimum. So the contact stress is considered as the target function of optimized designing, and many other factors are considered such as equation restriction and inequality restrictions. In the optimized designing the two-dimension variables are the tangent slope of the mesh points. In this thesis serial nonrestrict minimum method is applied to seek the best mesh points. It begins from the initial point and gets a pair of mesh points per step. After the movable pulleys reach the maximum position, this alternative ends and then the numerical values of the pulley genetrix are obtained. Compared with other genertrix the contact stress ont his optimized one has reduced 10 percent appromixedly. In this thesis the author also analyzed the effect of important parameters. By changing the initial parameters she got other numerical values of the genetrixs and calculated the contact stress. After analyzing and comparing the different results the author get the reasonable initial parameters and more perfect numerical values of the pulley's genetrix. Based on the numerical values the author drew the pulley's genetrix, which is the improvement on the straight one. It not only meets the requirement that the offset of the belt is zero in the timing, but also reduces the contact stress to the minimum, and then helps to enhance the carrying capacity of the CVT, taking on certain practical meaning. . Kinematic characteristics include principle of shifting ratio, ratio range, slipping principle between MVB and pulleys, steel ring and pushing blocks, steel rings each other. kinetic characteristics include driving principle, forces acting in MVB, pushing blocks compressive force distribution and rings tension force distribution in different ratio and the transmitted torque, changing condition of each force during steady state and transitional states. In addition, calculation formula is established between pushing force of driven pulley and transmitted maximum torque.Mechanics of steel ring group that is one of CVT's key part is emphasized in this thesis, numerical models of static state and driving state are proposed respectively. Excess fitness is adopted to bring about the present state in the steel ring group. As a result, load distribution in steel rings is even. The computational formula between excess quantity and transmitted torque is derived. The theoretical base for assembling ring group is provided. In addition, the computational formulas on tension force of each ring in driving state, stress changing pattern, position of maximum 。
What is Hydraulic? A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, no parts and hydraulic oil. The role of dynamic components of the original motive fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydraulic pump gears are generally pump, vane pump and piston pump. Implementation of components (such as hydraulic cylinders and hydraulic motors) which is the pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement. Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to the different control functions, hydraulic valves can be divided into the village of force control valve, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve. Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars. Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories. Hydraulic principle It consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. Water is called "hydraulic press"; the said oil-filled "hydraulic machine." Each of the two liquid a sliding piston, if the increase in the small piston on the pressure of a certain value, according to Pascal's law, small piston to the pressure of the pressure through the liquid passed to the large piston, piston top will go a long way to go. Based cross-sectional area of the small piston is S1, plus a small piston in the downward pressure on the F1. Thus, a small piston on the liquid pressure to P = F1/SI,Can be the same size in all directions to the transmission of liquid. "By the large piston is also equivalent to the inevitable pressure P. If the large piston is the cross-sectional area S2, the pressure P on the piston in the upward pressure generated F2 = PxS2 Cross-sectional area is a small multiple of the piston cross-sectional area. From the type known to add in a small piston of a smaller force, the piston will be in great force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel. History of the development of hydraulic And air pressure drive hydraulic fluid as the transmission is made according to the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 Joseph (Joseph Braman ,1749-1814), in London water as a medium to form hydraulic press used in industry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved. World War I (1914-1918) after the extensive application of hydraulic transmission, especially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th century, 20 years, only started to enter the formal phase of industrial production. 1925 Vickers (F. Vikers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundation. The early 20th century Constantine (G ? Constantimsco) fluctuations of the energy carried out by passing theoretical and practical research; in 1910 on the hydraulic transmission (hydraulic coupling, hydraulic torque converter, etc.) contributions, so that these two areas of development. The Second World War (1941-1945) period, in the United States 30% of machine tool applications in the hydraulic transmission. It should be noted that the development of hydraulic transmission in Japan than Europe and the United States and other countries for nearly 20 years later. Before and after in 1955, the rapid development of Japan's hydraulic drive, set up in 1956, "Hydraulic Industry." Nearly 20 to 30 years, the development of Japan's fast hydraulic 。
Three crossflow (No.1-No.3) dryers were tested. Dyer No.1 contains two crossflow columns, each column consists of two drying sections, one turn-flow device and a cooling section, and with a grain column thickness in the upper drying section of 0.277m and 0.304m in the lower section. The dimensions of dryer No.1 are 6.517m*3.400m*13.482m. No.2 dryer is similar to No.1, but is smaller and has a lower capacity. No.3 is a cylindrical crossflow dryer with two drying sections, one turn-flow device and a cooling section. The mixed-flow dryer (No.4) is composed of eight modular sections. Each module has dimensions of 1.8m*1.0m*0.8m. The tow bottom modules serve as cooling stage. Dryer No.5 consists of two mixed-flow drying towers in series, similar in design as dryer No.4. Dryers No.6-No.10 are concurrent-/counter-flow dryers, consisting of two or more towers. The number in front of “-CCF” indicates the number of towers. Each tower has two counter-/concurrent-flow drying sections. The last tower, or part of the last tower, is used for cooling. The depth of the counter-/concurrent-flow beds is 0.6m, the cross-sectional area of each tower is 2.2m*2.2m. It should be noted that overseas CCF dryers do not have counter-flow drying stages, only a counter-flow cooling stage. The steam dryer is a unique dryer widely used in grain depots in China. It consists of 3-6 indoor drying and cooling towers, and a boiler. Each tower contains in its upper section a series of steam pipes, and in its lower section a number of inlet/outlet air ducts. The grain is heated by conduction as it flow over the steam-heated pipes, and is subsequently treated with ambient or slightly-heated recycled drying-air. The steam pressure in the pipes is 2*105Pa--4*105Pa (130-140℃), the diameter of the pipes is 42-48mm, and the distance between pipes is 110-120mm. The grain retention time is long (4-6 hours for 10-point moisture removal) due to the relatively low grain temperature. Sun drying is still the main method of grain drying in China. Almost every village or depot has a special area for the sun drying of grains. The grain is spread out in 5-10cm thin layer and is stirred occasionally. In Northeast China where the ambient temperature is very low when maize is harvested, sun drying is a very slow process. 三橫(一號(hào)至三號(hào))烘干設(shè)備進(jìn)行了測(cè)試. 戴先生no.1包含兩個(gè)橫欄,每欄分為兩部分干燥, 一轉(zhuǎn)流器及冷卻段, 與糧食柱厚度在上部干燥部分0.277m和0.304m在下游. 尺寸干燥器一號(hào)是6.517m*3.400m*13.482m. 二號(hào)烘干機(jī)相似一號(hào),但規(guī)模較小,具有容量較低. 第三是橫向圓筒烘干機(jī)烘干兩部分,一部分是轉(zhuǎn)流裝置和冷卻段. 混流式干燥機(jī)(四號(hào))是由八個(gè)單元章節(jié). 每個(gè)單元尺寸1.8*1.0*0.8米. 拖車(chē)底部模塊作為冷卻階段. 干燥器no.5分為兩個(gè)混流干燥塔系列,類(lèi)似的設(shè)計(jì)作為烘干四號(hào). 干衣no.6-no.10都是concurrent-/counter-flow烘干機(jī),由兩個(gè)或兩個(gè)以上的彈孔. 數(shù)年前的"框架",表明了很多水塔. 每個(gè)塔有兩個(gè)counter-/concurrent-flow曬路段. 最后塔,或部分上塔,是用于冷卻. 有深度的counter-/concurrent-flow病床0.6m,橫截面的每個(gè)塔有2.2m*2.2m. 應(yīng)當(dāng)指出,海外ccf干衣沒(méi)有反流干燥階段,只有一個(gè)反流冷卻階段. 蒸氣烘干是一個(gè)獨(dú)特的烘干機(jī)廣泛用于糧庫(kù)中. 它由3-6室內(nèi)干燥,冷卻水塔,一臺(tái)鍋爐. 每個(gè)塔載在其上部一系列的蒸汽管道, 而在其下游的一系列進(jìn)/出水口風(fēng)筒. 谷物的熱傳導(dǎo),因?yàn)樗髁苏羝訜峁埽?并隨后處理空氣或微循環(huán)加熱干燥的空氣. 蒸汽壓力管道2*105pa--4*105pa(130-140℃),直徑較小的管材是42-48mm, 之間的距離和管道是110-120mm. 糧食停留時(shí)間很長(zhǎng)(4-6小時(shí),10點(diǎn)去濕)由于相對(duì)較低的糧食溫度. 晾曬仍然是主要的方法谷物干燥中. 幾乎每一個(gè)村或倉(cāng)庫(kù)具有特殊的地區(qū),以供晾曬谷物. 糧食是分布在5-10cm薄層,偶爾攪拌. 在東北那里的氣溫很低,當(dāng)玉米收割, 太陽(yáng)曬是一個(gè)非常緩慢的過(guò)程。
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Mechanical Principle is a subject that studies the structure and movement of mechanisms in machineries, and the structure, exerted force, mass, and movement of machines. People generally call mechanism and machine jointly as machinery. Mechanism is a combination object that realizes specified movement through more than two moving joints. Machine is composed of one or above one mechanism, and it is used to do useful work or complete the energy conversion between mechanical energy and other forms of energies. The main components of this subject are mechanism and mechanical dynamics.
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