5000KN單臂液壓機的液壓系統(tǒng)設(shè)計【說明書+CAD】

5000KN單臂液壓機的液壓系統(tǒng)設(shè)計【說明書+CAD】,說明書+CAD,5000KN單臂液壓機的液壓系統(tǒng)設(shè)計【說明書+CAD】,kn,液壓機,液壓,系統(tǒng),設(shè)計,說明書,仿單,cad 江南大學(xué)太湖學(xué)院 系 專業(yè) 畢 業(yè) 設(shè) 計論 文 任 務(wù) 書 一、題目及專題： １、 題目 5000kN單臂液壓機的液壓系統(tǒng)設(shè)計 ２、專題　 　 二、課題來源及選題依據(jù) 設(shè)計題目為無錫某企業(yè)在建系統(tǒng)，采用典型的插裝閥集成系統(tǒng)，在機床、內(nèi)燃機、汽車電器、軍工企業(yè)等行業(yè)都有應(yīng)用，目前的液壓控制由于其力大、平穩(wěn)等優(yōu)點，在控制系統(tǒng)中占比越來越大，學(xué)生通過該系統(tǒng)設(shè)計，能綜合運用所學(xué)的機械知識和液壓與氣動控制的知識。解決生產(chǎn)中的實際問題。 三、本設(shè)計（論文或其他）應(yīng)達到的要求： 1. 液壓系統(tǒng)設(shè)計，繪制液壓系統(tǒng)圖，選擇典型的液壓元件 2. 液壓系統(tǒng)典型回路設(shè)計； 3. 液壓元件的選用； 4.編寫設(shè)計說明書（大于30頁）； 5.專業(yè)外語翻譯（大于8000~10000字符，約合漢字5000字符）； 四、接受任務(wù)學(xué)生： 班 　　姓名 五、開始及完成日期： 自 年 月 日 至 年 月 日 六、設(shè)計（論文）指導(dǎo)（或顧問）： 指導(dǎo)教師　 薛慶紅 　簽名 簽名 　　　　　　　簽名 教研室主任 　　　　　　　〔學(xué)科組組長研究所所長〕　　　　　　　簽名 　　 　　系主任 　　　　　　簽名 年 月 日 5000kn單臂液壓機（略見圖紙） 參數(shù)按下表而定（500T型號的） 型號 單位 45T 63T 100T 160T 200T 315T 400T 500T 630T 公稱力 KN 400 630 1000 1600 2000 3150 4000 5000 6300 頂出力 KN 63 100 200 250 400 630 630 1000 1250 液體最大工作壓力 MPa 25 25 26.5 26 25 25 25 26 26 滑塊行程 mm 400 500 500 500 700 800 800 900 900 最大開口高度 mm 600 700 900 900 1120 1250 1400 1500 1500 工作臺尺寸 前后 mm 400 500 580 800 900 1200 1200 1400 1600 左右 mm 400 500 710 800 900 1200 1260 1400 1600 頂出行程 mm 120 160 200 200 250 300 300 300 400 滑塊速度 空程下行 mm/s 40 76 100 100 100 100 100 100 >100 工作 mm/s 10 10 8-15 8-15 8-15 8-15 8-15 10 12 回程 mm/s 60 60 60 60 70 70 70 80 65 機床外形尺寸 左右 mm 1000 1100 1200 1600 2120 2220 2220 2420 2520 前后 mm 500 650 380 400 500 500 650 680 700 地面上高度 mm 2406 2430 3300 3350 3690 3900 4050 5348 　　 電機功率 KW 5.5 5.5 7.5 15 18.5 22 22 37 　　 總重量 T 1.95 2.5 4 7 12 15 20 30 無錫太湖學(xué)院 畢業(yè)設(shè)計（論文） 開題報告 題目：5000KN單臂液壓機的液壓系統(tǒng)設(shè)計 信機 系 機械工程及自動化 專業(yè) 學(xué) 號： 0923812 學(xué)生姓名： 詹 頌 指導(dǎo)教師： 薛慶紅 （職稱：副教授） （職稱： ） 2012 年 11月 21日 課題來源 無錫某企業(yè) 科學(xué)依據(jù)（包括課題的科學(xué)意義；國內(nèi)外研究概況、水平和發(fā)展趨勢；應(yīng)用前景等） （1）課題科學(xué)意義 隨著近50年的科學(xué)技術(shù)的進步與發(fā)展，液壓技術(shù)已經(jīng)成為了一門影響現(xiàn)代機械裝備技術(shù)的重要基礎(chǔ)學(xué)科和基礎(chǔ)技術(shù)，液壓機是一種利用液體壓力來傳遞能量,以實現(xiàn)各種壓力加工工藝的機床。隨著新工藝及新技術(shù)的應(yīng)用，液壓機在金屬加工及非金屬成形方面的應(yīng)用越來越廣泛，在機床行業(yè)中的占有份額正在大幅度攀升。通過對本課題進行設(shè)計，進一步理解和掌握液壓系統(tǒng)、液壓機、機械加工工藝等的理論知識，了解先進液壓技術(shù)、工藝技術(shù)，提高液壓系統(tǒng)分析能力、結(jié)構(gòu)設(shè)計能力，加強分析和解決現(xiàn)場機械和結(jié)構(gòu)設(shè)計問題的能力，為以后工作時的產(chǎn)品開發(fā)、技術(shù)改進打下堅實基礎(chǔ)，并在實際的生產(chǎn)中靈活處理質(zhì)量、生產(chǎn)率和成本之間的關(guān)系，獲得良好的經(jīng)濟效益。國外企業(yè)的競爭，國內(nèi)用戶要求的不斷提升，液壓機走創(chuàng)新路子，形成核心競爭力的呼聲更高。國產(chǎn)液壓機械與國外同類產(chǎn)品的差距，除了研發(fā)能力．技術(shù)創(chuàng)新不足之外，還主要表現(xiàn)在液壓性能和運行可靠性兩個方面。因此，必須下大力氣研究從生產(chǎn)過程、管理過程．流通過程與創(chuàng)新的系統(tǒng)優(yōu)化問題，借助系統(tǒng)論控制論的理論，努力消除現(xiàn)存的問題，縮短差距。應(yīng)加強產(chǎn)學(xué)研結(jié)合，開創(chuàng)教育與企業(yè)新局面。通過企業(yè)和科研院所的人才與設(shè)施、科研與生產(chǎn)互動，加快人才培養(yǎng)和技術(shù)提升。 研究液壓機的傳動系統(tǒng)，對于提高生產(chǎn)效率降低生產(chǎn)成本具有重要意義。此項研究也是對大學(xué)四年所學(xué)課程的一次總復(fù)習，它將機械制圖、液壓設(shè)計和液壓傳動等機械設(shè)計制造及其自動化主要專業(yè)課程緊密聯(lián)系在一起,利用所學(xué)的機械與控制相關(guān)知識來解決實際的生產(chǎn)問題，將理論設(shè)計與實際運用聯(lián)系起來，需要考慮多方面的問題，如成本、系統(tǒng)可靠性和機械設(shè)備使用壽命等等。 （2）發(fā)展趨勢 1、配有自動上下料裝置的液壓機或自動生產(chǎn)線將會成為未來液壓機發(fā)展的方向。 2、多工位液壓機的需求將會大幅度增加?？焖?、高速液壓機在批量生產(chǎn)中能成倍地提高效率。 3、依托電液比例技術(shù)、傳感器、電子、計算機、網(wǎng)絡(luò)等提升液壓機的性能。 4、在環(huán)保、節(jié)能方面，今后在液壓機的設(shè)計及制造中應(yīng)引起各制造企業(yè)的足夠重視。 研究內(nèi)容 通過調(diào)研應(yīng)明白要對一個系統(tǒng)進行改進或創(chuàng)新以滿足生產(chǎn)的需求，信息的獲取是非常重要的，分析5000KN單臂液壓機工作要求，完成5000KN單臂液壓機件的設(shè)計研究的結(jié)構(gòu)分析、元件的選用等，在滿足生產(chǎn)工作要求的情況下，應(yīng)盡可能提高效率，提高系統(tǒng)的穩(wěn)定性，以減少產(chǎn)品的設(shè)計生產(chǎn)成本。 擬采取的研究方法、技術(shù)路線、實驗方案及可行性分析 通過現(xiàn)場調(diào)研與相關(guān)資料查閱，對5000KN單臂液壓機進行系統(tǒng)分析，并通過模擬實驗分析建立5000KN單臂液壓機工作狀態(tài)實體模型，設(shè)計5000KN單臂液壓機的液壓系統(tǒng)結(jié)構(gòu)和參數(shù)，進行現(xiàn)場實驗，來進行系統(tǒng)設(shè)計的合理性。 特色或創(chuàng)新之處 適用于本企業(yè)的某生產(chǎn)線的設(shè)計，可降低工人的勞動強度和生產(chǎn)成本。 研究計劃及預(yù)期成果 研究計劃： 2012年10月12日-2012年12月25日：按照任務(wù)書要求查閱論文相關(guān)參考資料，填寫畢業(yè)設(shè)計開題報告書。 2013年1月11日-2013年3月5日：填寫畢業(yè)實習報告。 2013年3月8日-2013年3月14日：按照要求修改畢業(yè)設(shè)計開題報告。 2013年3月15日-2013年3月21日：學(xué)習并翻譯一篇與畢業(yè)設(shè)計相關(guān)的英文材料。 2013年3月22日-2013年4月11日：撰寫設(shè)計說明書。 2013年4月12日-2013年4月25日： 裝配圖、零件圖的繪制。 2013年4月26日-2013年5月21日：畢業(yè)論文撰寫和修改工作。 已具備的條件和尚需解決的問題 針對實際使用過程中5000KN單臂液壓機的液壓系統(tǒng)存在的不足，綜合所學(xué)的機械理論設(shè)計與液壓傳動理論，如何對5000KN單臂液壓機系統(tǒng)進行再次的改進和完善，進而提高學(xué)生開發(fā)和創(chuàng)新機械產(chǎn)品的能力。 指導(dǎo)教師意見 指導(dǎo)教師簽名： 年 月 日 教研室（學(xué)科組、研究所）意見 教研室主任簽名： 年 月 日 系意見 主管領(lǐng)導(dǎo)簽名： 年 月 日 Hydraulic System There are only following three basic methods of transmitting power : electrical，mechanical ,and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to understand the characteristic of each method. For example，hydraulic systems on the long distance economically deliver power more than mechanical systems. However, fluid systems are restricted to shorter distances than electrical systems. Hydraulic power transmission systems are concerned with the generation, modulation, and control of sculptress and flow, and in general such systems include: l. Pumps convert available power from the prime mover to hydraulic power at the actuator. 2. Valves control the direction of pump- flow, the level of produced power, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level. 3. Actuators convert hydraulic power to usable mechanical power output at the point required. 4. The medium is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system. 5.Connectors link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank（reservoir). 6. Fluid storage and conditioning equipment ensure sufficient quality and quantity as well as cooling of the fluid. Hydraulic systems are used in industrial applications such as stamping presses, steel mills and general manufacturing, agricultural machines, mining industry, aviation, space technology, deep-sea exploration, transportation, Narine technology, and offshore gas and petroleum exploration. In short, many people get somehow benefiting from the technology of hydraulics. The secret of the success and widespread use of the hydraulic system is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material. Industry is going to depend more and more on automation in order to increase productivity. This includes remotion and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of the advantages in the following four major categories. 1. Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power system can readily start , stop ,speed up or slow down, and provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch. 2. Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply force simply and efficiently create the output from a fraction of an ounce to several hundred tons. 3. Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. It produces the work output moving from a few inches per hour to several hundred inches per minute, or from a few revolutions per hour to thousands of revolutions per minute. 4. Simplicity, safety, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control design has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the steering unit is fully fluid-linked, without the link of mechanical linkages, universal joints, bearings, reduction gears, etc. This provides a simple, compact system. In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of control space require a small steering wheel and it becomes necessary to reduce operator fatigue. Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely eliminate. Also, most hydraulic oils can cause tires if an oil leak occurs in an area of hot equipment.Now, a concrete example is following - we use hydraulic stations to introduce the advantages of the hydraulic system. Hydraulic Station and the development of hydraulic components Profiles Hydraulic Pump Station also known as the stations is independent hydraulic device. It is requested by the oil gradually and controls the hydraulic oil flow direction, pressure and flow rate, applied to the mainframe and hydraulic devices ability of hydraulic machinery. Users just need to connect hydraulic station and host of implementing agencies (motor oil or fuel tanks) with tubing. Hydraulic machinery can realize these specified movements and the work cycle. Hydraulic pump station is equipped with Pump device, manifold or valve portfolio, tanks, electrical boxes. Pump device -- is equipped with motors and pumps. Hydraulic station is the source of power and can translate mechanical energy into hydraulic oil pressure. Manifold -- is installed by hydraulic valve and assembled channel. It has the function of adjusting the direction for implementation of hydraulic oil, pressure and flow. Valve portfolio -- plate valve is installed in up board, the back board connects and has the same functional with IC. Tank -- plate welding semi-closed containers, also is loaded with oil filtering network, air filters ans is used to save oil, oil filters and cooling. Electrical boxes -- has the two patterns. A set of external fuse terminal plate and a full range of control electrical. The principle of the hydraulic Station: the motor drives pump rotation, pump absorbs oil from the oil tank, then translates mechanical energy into hydraulic pressure of the station. Hydraulic oil through Manifold (or valve combinations) realized the direction, pressure. After adjusting flow pipe, it external flows to the cylinder hydraulic machinery or motor oil, so as to control the direction of the motive fluid, the size of transformation force and the speed of the pace, finally it promotes hydraulic machinery to the various acting. Firstly, A development course China Hydraulic (including hydraulic, the same below), pneumatic and seals industrial development process can be broadly divided into three phases, namely : the early 1950s to the early 1960s is the initial stage. The 60s and 70s is the growth stage for specialized production system.The80s-90s is the growth stage for the rapid development .Meanwhile, hydraulic industry started in the early 1950s from the machine tool industry production of fake us-grinder, broaching machine, copying lathe, and other hydraulic drive. Hydraulic Components from the plant hydraulic machine shop is self-occupied. After entering the l960s, the application of hydraulic technology from the machine gradually extended to the agricultural machinery and mechanical engineering fields, attached to the original velocity of hydraulic shop some stand out as pieces of hydraulic professional production. To the late 1960s, early 1970s, with the development of mechanized production, especially the second automobile factory provides efficient, automated equipment. The Hydraulic Components manufacturing has experienced rapidly development of the situation. Groups of SME have become professional hydraulic parts factory. China annual output of hydraulic components has nearly 200.000 in 1968. Machine tools, agricultural machinery, mechanical engineering industries, the production of hydraulic parts factory have been the professional development of more than 100 and an annual output more than one million in 1973 and an independent hydraulic manufacturing industry has begun to take shape. Then , hydraulic pieces of fake products has developed from the Soviet Union for the introduction of the product and combining the products .Hypertension has developed to medium and high pressure and the development of the electro-hydraulic servo valves and systems, hydraulic application areas further expanded .Pneumatic industry started later than the industrial hydraulic years. Until 1967 professional pneumatic components factory began to establish . Pneumatic Components looked only as commodity production and sales. It deal with rubber and plastics, mechanical seals and sealing flexible graphite . In the early 1950s, it produced ordinary 0-rings, rubber and plastics extrusion, such as oil seal sealing and seal asbestos. Until the early 1960s,it begun to production of mechanical seals and flexible graphite sealing products. In 1970s, under the burning of the former Ministry, a Ministry, the Ministry of Agricultural Mechanization System, a group of professional production plants have been established, and the official establishment of industries to seal industrial development has laid the foundation for growth. Since the l980s, under the guidelines of country’s reform and opening up policy , with the development of the machinery industry, based mainframe pieces behind the conflicts have become increasingly prominent and attracted the attention of the relevant departments. To this end, the Ministry originating in 1982 and formed the basis of common pieces of Industry, will centralize hydraulic, pneumatic and seals specialized factories original machine tools scattered in agricultural machinery, mechanical engineering industries and place them under common management infrastructure pieces Bureau, so that the industry in the planning, investment, technology and scientific research and development in areas got the guidance and support of infrastructure pieces Bureau. Since then it entered a phase of rapid development and has introduced more than 60 items of advanced technology from abroad, including more than 40 items of hydraulic, pneumatic 7. After digestion and absorption and transformation, now they have mass production, and industry-leading products. In recent years, the industry has increased the technological transformation efforts.Fom1991 to 1998,state,Local enterprises and the self-Financing have fund total input of about 20 billion ￥, of which Hydraulic was more than I .6 billion￥ . Through technological transformation and technology research, a number of major enterprises have further improved the level of technology, technique and equipment, which has laid a good foundation in order to form a higher Starting point, specialization, and run production . In recent years, under the guidelines of development of common ownership, different ownership SME rapidly have rise to show great vitality. With the further opening up, three-funded enterprises developed rapidly which played an important role to the development of industry standards and expanding exports. Today, China and the United States, Japan, Germany and other countries famous manufacturers have established joint ventures or wholly-owned by foreign manufacturers which involved in a piston pump / motor, planetary reduction gears, steering gear, hydraulic control valve, hydraulic system, hydrostatic transmission, hydraulic Casting, pneumatic control valve, cylinder, gas processing triple pieces, mechanical seals, rubber and seal products. It has more than 50 production enterprises and attracted foreign investment over 200 million U.S. dollars. Secondly, the current situation （1）Basic Profiles After 40 years of efforts, China hydraulic, pneumatic and sealing industry have formed the industrial system with a relatively complete categories, a certain level of technical capacity. According to the 1995, Third National Industrial Census statistics said that state-owned, village-run, private and cooperative enterprises, individual, “three capital” enterprises with a total of more than 1,300 engaged in hydraulic Pneumatic and sealing parts industry with annual sales income of 100 million￥, of which hydraulic is about 700, Pneumatic and sealing parts industry is approximately300. By 1996 with the international trade statistics, the total output value of China’s hydraulic industry is 2.348 billion￥, accounting for the world’s 6, the output of Pneumatic industry is 419 million￥, accounting for world No. 10. （2）The current supply and demand profiles Through the introduction of technology, independent development and technological innovation, high-pressure piston pump, gear pumps, vane pump, General Motors hydraulic valves, tanks, non-lubricated aerodynamic pieces and various seals of the first large technology products have increased noticeably and they can have stability mass production and provide a level of assurance for various mainframe products. In addition, they scored some achievements at hydraulic and pneumatic components of the CAD system, pollution control, proportional servo technology, and have been already in production. Currently, hydraulic, pneumatic and seals products totally have about 3,000 species, more than 23.000 specifications. Among them, there are 1,200 hydraulic varieties, more than I 0,000 specifications (including hydraulic products 60 varieties,500 specifications): Pneumatic has 1 .350 varieties, more than 8,000 specifications: Rubber seal has 350 species, more than 5,000 specifications, they basically cater to the different types of mainframe products to the general needs. The complete sets of equipment for major varieties of matching rate was over 60%, and it started a small amount of exports. In 1998 the output of homemade hydraulic is 4.8 million, the sales of which is about 28 billion (of which about 70% is mechanical systems);The yield of aerodynamic is 3.6 million, Sales of which is about 5.5 billion (of which about 60% is mechanical systems). Seals output is about 800 million, sales of which is about 10 billion (of which about 50% is mechanical systems). According to the China 1998 annual Hydraulic Pneumatic Seals Industry Association, the rate of hydraulic product sales is 97. 5% (101% for hydraulic), pneumatic 95.9%, sealed 98.7%. This fully reflects the basic marketing convergence. Our country hydraulic, pneumatic and sealing industry have attained a great deal of progress, but compared with mainframe development needs, and the world’s advanced level, there are still many gaps, mainly reflected in the product variety, performance and reliability, and so on. Hydraulic products as an example, is the same one-third of products abroad. life is for half abroad. In order to meet key mainframe, and mainframe imports of major technology and equipment needs, every year we import a large number of hydraulic, pneumatic and sealing Products. According to customs statistics and the analysis of data, in 1998,the import sales of hydraulic, pneumatic and seals is about 200 million U.S. dollars, which Hydraulic is about 1.4 billion dollars, aerodynamic is nearly 0.3million U.S. dollars, sealed industry is about 0.3million U.S. dollars. It is a slight decline compared with 1997 . By sums, currently the domestic market share of the imported products is about 30%. In 1998 ,the demand of domestic hydraulic market is total of about six million, the total sales is nearly 40 billion. The total demand of aerodynamic is about 5 million, with sales more than 0.7 billion ￥The total demand of Seals is about 1.1 billion, the total sales is about 1.3 billion. Thirdly, the development trend of the future 1.the main factors of affecting the development (1) The product development ability, and the level of technological development and speed can not completely meet the advanced mainframe products, major equipment and technology imported equipment and maintenance support: (2) The manufacturing technology, the level of equipment and management standards of A number of enterprises are comparatively backward, along with a week sense of quality, which result in low levels of product performance quality, reliability poor services in a timely manner, lack of satisfaction and trust of the brand-name products: (3) The production low of industry specialization, scattered strength, low repeat serious, the convergence products between regions and enterprises, blindly competing with each other, driving down prices, the decline of enterprise returns, lack of funds, difficult liquidity, the inadequate product development and technological transformation seriously have restricted the industry to improve the overall level of competition and competitive strength. (4) As the internationalization of the domestic market is increasing, foreign companies have entered the Chinese market and participate in competition with the domestic private and cooperative enterprises, individuals, foreign-funded enterprises and so on. As the rise of state-owned enterprises has more and more big impact to state-owned enterprises. 2 .The development trend As the socialist market economy continues to deepen, the relationship of supply and demand of hydraulic, pneumatic and sealing products in the market has a greater change. Long ago, the characterized by "shortage" of the seller's market has basically become the characterized by excess "structural" buyer's market. Look from the overall ability, it is in oversupply situation, especially the supply of the generally low grade of hydraulic, pneumatic and sealing parts, generally exceeds the demand, but the host need high parameters of high technical content, high value-added high-end products, and can't meet the needs of the market, it can only rely on imports. After China's accession to the WTO, its impact could be bigger. Therefore, during "15" , the growth of the industry output value must not be dependent on the amount of growth and should increase, adjust the industrial structure and product structure according to the structural contradiction of industry , namely we should rely on quality, technology upgrade, promote products to meet the market demand and pull, seek a bigger development. Pneumatic pressure system Pneumatic pressure system is pressure gas transmission system and control power, as the name suggests, usually it uses air pressure (no other gas) as the fluid medium. Because air is a safe, low cost and widely available fluid. It is safe that Air in system components may ignite the leakage situation (using air as medium) in particular. In pneumatic systems, compressors are used for compressed air and supply the required. Usually it has a piston compressor, screw and vane type. Compressor is basically according to the ideal gas law, by reducing its volume to increase the gas pressure. Pneumatic system is usually considered using large central air compressor as an unlimited source, this is similar that as long as the plug in the power system lift up into the socket and power can be obtained. Using this method, the gas pressure can be transmitted from the source to every corner of the whole factory. The gas pressure can remove dirt through the air cleaner. the dirt is likely