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中國礦業(yè)大學(xué)2008屆本科生畢業(yè)設(shè)計
Summarization and improvement of concrete-ejecting machines
FAN Hua QIULinfeng CHENLingfang
Abstract :The text introduces the principle ,style and development process of dry and wet type concrete-ejecting machines. It analyzes domesticand foreign application instance ,allkindsofconcrete-ejecting machines mostly merit and flaw. Also it introduces somerepresentational wet con-crete-ejecting machines domestic developed. Some flaws of concrete-ejecting machines are improved.
Keywords:concrete-ejectingmachines,frame characteristic ,operating principles , highway.
Concrete is the use of compressed air jet, will be allocated a certain level and good water-cement ratio mixing concrete materials, through the pipeline by the jet nozzle, and high speed jet out to the surface by spraying a concrete suppor-t Layer is sprayed concrete construction equipment operations in the main. Asa concrete spraying technology saving concrete and steel, timber, labour-saving and improve construction efficiency and reduce costs, and other characteristics, the concrete applican of the jet increasingly common. Has now been widely us-ed in railway, highway, water conservancy, construction, coal and other buildi -ng works in construction, a tunnel solution, road slope, construction pit, unde-rground works of temporary and permanent care to support the construction m-achinery operations. [ 1 ]
1 The work of sprayed concrete mechanism and the development trend
In sprayed concrete operations, the overwhelming majority of the use of concrete-rotor aircraft, such as jet structure is simple, reliable performance, a small, lightweight, easy to operate and maintenance。Dry jet principle and structure are: the rotor with a liner to a certain speed of rotation, and the combination of pressure plates fixed on the liner fixed, with a board connected into the wind pipe and discharging elbow, when Rotor equipped with materials in the various materials Cup rotation and into the wind to the elbow and discharging the same time, in the role of gas under pressure, and materials through the elbow and expected to lose the material transported to the nozzle a nd nozzle in the water Blasting away.
Dry concrete jet of the main advantages is a long distance carrier, simple equipment, durable, but because it is so dry nozzles, mixing concrete mixed with water, and therefore the construction dust, are more resilient, dry spraying operations against workers in the dust Health, in particular the narrow roadway construction, dust pollution is more serious [2]。
From the 1960s onwards, in Western developed countries, wet spraying began gradually introducing the technology, all kinds of wet concrete Jets also be developed, sprayed concrete and dry the main difference is that enough (in water-cement ratio requirements should be The volume of) the opportunity to join the mixing of different water。Wet sprayed concrete is expected lose their access to the former Mixture has added a foot of water mixing, the loser in the delivery of the cylinder is the wet concrete; dry sprayed concrete is lost in the transmission of the material did not join the mixing Water dry material (ground humidity mixing natural materials or drying materials), and in sufficient volume nozzle before mixing with water, dry mixture and mix quickly after the whole wet concrete delivered to the nozzle, speed up the coagulation of the doped Afte r the jet to beam a material of construction [3].
At the national level, as people's environmental awareness and enhance the quality of sprayed concrete requirements of the increase, an increasing number of wet concrete into the use of jet aircraft. In recent years, some domestic units also began to develop several wet concrete jet, but the scale of production is still to be expanded. To sum up, jet wet concrete of the main advantages are the following:
1) greatly reduced the plane and next to the nozzles of dust concentration and eliminate the health hazards to workers.
2) high productivity. Dry concrete Jets general no more than 53 m3 / h, and the use of jet wet concrete, artificial operations up to 103 m3 / h, a mechanical manual, up to 203 m3 / h.
3) The rebound was low. Jet Dry, concrete rebound of up to 15 percent to 50 percent, the wet spray technical rebound rate can be reduced to below 10%.
4) wet spray, easy to control because of water-cement ratio, a high degree of concrete hydration, it can significantly improve the quality of sprayed concrete and improve quality of the concrete absorbed.
2 Wet concrete Jets and the type of work principle
Concrete Pumping main piston pump-jet spray and a wet-wet spraying machine screw pump two categories. Piston pump-jet aircraft will be wet plunger-wet concrete as a concrete pump the basic body jet, with the export pipeline to the nozzle and in this Access to compressed gas will jet out of concrete, wet spray such a heavy machine general However, long distance transmission, Second Beach, the Xiaolangdi Water Conservancy Project and other large-scale use of the aircraft's main disadvantage is that low productivity, and screw the stator sets of wear and tear more serious, there was little scope of application.
3 Domestic wet concrete Jets
3. 1 SPZ26-wet concrete Jets
SPZ26-wet concrete jet sent to a gas-rotor aircraft wet concrete, and its working principle of Liwa 280 Ruishi A similar model, by its rotor rotary motor driven by reducer, the aircraft equipment less investment, high productivi ty, light weight , Good mobility [4].
3. 2 PZ25B Concrete jet aircraft to spray dry, wet spray and spray tide. It automatically clean, non-stick block, cutting speed, little more than expected, h igh efficiency.
3.3 impeller wet concrete wet concrete impeller jet aircraft is a new wet spraying machine, it adopted a impeller feeding device, a reliable, long life, to aggregate size of the big advantages. At present, China's development of the wet concrete pumping and dual-use spray-spray-wet concrete tunnel construction is indispensable to engineering equipment, the main impeller and rotor piston-type pumps and wet spraying machine. Impeller and rotor piston wet spraying machine short-distance transportation, displacement of small, fragile pieces of short life, serious leakage pulp, cleaning a long time [5].
4 Jet promote the use of wet concrete in some of the issues to be resolved
At present, due to wet jet technology has obvious advantages, wet concrete Jets in the project is also an increasing number of applications, but because there are some outstanding issues, the wet concrete to promote the use of jet played a certain obstacles Role, even in China, currently the main sprayed concrete operations is still dry spray.
1) use of wet concrete jet of liquid condensate, a joint venture of imports and higher prices (up to 6000 yuan / t ~ 8 000元/ t), and domestic liquid condensate of no production, should be relatively dry Spray of powder and quick-setting low price (more than 1000 yuan / t).
2) low labor costs and people's environmental awareness to be increased.
3) wet concrete jet operations, more complex equipment, operation and maintenance of jet aircraft for less than dry. 4) the use of wet concrete jet operations, higher equipment investment.
5 Improvement of concrete-ejecting machines
5.1 After the concrete improvement of the characteristics of a jet
1) dust better. The improved use of the seal can not be dust, has greatly improved the working conditions of workers, increased labor productivity.
2) increase the flexibility of high-adhesive rubber material cavity. Concrete can be an effective solution to the problem of bonded easily, remove the concrete to reduce the number of bonded and improve labor efficiency.
3) use of wear-resistant rubber pads. Rubber mats more than double the wear resistance, a decrease of rubber pads to reduce the frequency of the use of replacement cost.
4) the overall change from the original drive shaft composed of three parts, not easy to solve the demolition, the problem of maintenance.
5.2 Improve the difference between before and after the concrete Jets
1) the original concrete jet rotating body formed by the wear-resistant cast iron foundry, without treatment, after the rust-bonding, improved after the jet cavity spraying anti-rust treatment and greatly reduce the possibility of a bond.
2) the original concrete jet rotation of direct contact with the material I, Mifengbuyan; feed mouth without sealing device, improved to increase a wear-res istant rubber pads and mouth and feed ring.
3）In rotating body and mouth spray to increase flexible rubber material, and the rotation of the original concrete jet spray and a flexible rubber mouth cavity. Concrete work of a high-pressure jet of air cavity, flexible rubber in the air cavity under the pressure of being compressed, rotating body is constantly rotating, when the rotation of the chamber passed a flexible rubber pressure zone, the pressure disappeared, flexible Rubber cavity in the stretch under its own restitution due to the high flexibility of rubber attached to the cavity on the concrete and scattered by squeezing down, automatic removal of the concrete bonding, in order to facilitate maintenance and replacement of the rotating flexible rubber Liu cavity, the overall 12 will be split into four cavity, each of the three cavity. The same token, I expected to increase in a flexible rubber material cavity.
4) the original concrete jet drive shaft for the overall structure, cleaning up the rotating body cavity or replacement work flexible rubber material cavity, to be screened in Shangzuo body and can also Xiediao, will improve the entire shaft is divided into three parts , The middle of a connecting shaft, through the home side, connecting shaft, the pin will be linked to the two-axis, demolition, only to tear down the shaft can be connected in blocks of lift, the replacement of flexible rubber body cavity or clean-up rotation, Province when the effort, boosted by increasing the flexibility of rubber rubber seal cavity and the drive shaft connected to the body structure and effective solution to the dust and inconvenience to the demolition of concrete and bond issues, some use from the scene, has been made Good results.
6 The end
conclusion of a wave while spraying can reduce dust concentration and reduce the rate of rebound, but the dust hazard still exists, still higher rates rebound from the required standard there is still a considerable distance. All countries in the world of wet concrete of the jet at the same time, developed a jet of wet concrete, and increasingly mature, many countries have started to use a lot. China's current wet-spray method is still in testing stage and not yet fully promote the application level. Mainly wet spraying machine size, complexity of the aggregate demand high, and China's production of liquid condensate, the admixture of poor, the impact of the wet jet promotion and application. In this regard China's many units have begun research, and has made big progress [7]. Development of reliable performance, small size, for the scene to promote the use of the wet spraying machine is still the future of sprayed concrete technology one of the main direction.
[1] Xu Tianen. Concrete Jets the status quo and development trend of [J]. Coal Science and Technology, 1997, 25 (9): 30231.
[2] Liu Yun Kai. Concrete dust and jet-bonded improvements [J]. Jiangsu coal, 2003 (4): 61262.
[3] Wang Xiaobao. Wet concrete Jets and the type of development [J] . Engineering machinery, 2004 (11): 48249.
[4] Chen Hui-Han. Improve rotor aircraft service life of concrete technical means [J]. Well built, 2003 (8): 36237.
[5] Fan Guang-qin, Zeng Kang Sheng, Xu Long Wharf, etc. jet fly ash concrete support of the pilot study [J]. Well built, 1993 (2): 66267.
[6] Yi Gong initiatives, Han Jun, ZHANG Ren-water. High Strength of sprayed concrete [J]. Coal Science and Technology, 1993, 21 (2): 40242.
[7] Wang Fangrong. Analysis of China's concrete spraying technology and equipment [J]. Well built, 1996, 79 (5 ): 45,246
中文譯文
混凝土噴射機(jī)的概述及改進(jìn)
樊 華 邱林鋒 陳玲芳
摘 要:介紹了干式和濕式混凝土噴射機(jī)的工作原理、類型、發(fā)展過程,分析了國內(nèi)外應(yīng)用情況和各類混凝土噴射機(jī)的優(yōu)缺點,并對近年來國內(nèi)研制開發(fā)的幾種具有代表性的濕式混凝土噴射機(jī)作了介紹,對混凝土噴射機(jī)的問題進(jìn)行了技術(shù)改進(jìn)。
關(guān)鍵詞:混凝土噴射機(jī),結(jié)構(gòu)特點,工作原理,公路
混凝土噴射機(jī)是利用壓縮空氣,將按一定級配和水灰比拌和好的混凝土料,通過輸送管經(jīng)噴射機(jī)的噴嘴,并以很高的速度噴射出去,從而在受噴面上形成混凝土支護(hù)層,是目前噴射混凝土施工作業(yè)中的主要設(shè)備。由于混凝土噴射技術(shù)具有節(jié)約混凝土和鋼材、木材,節(jié)省勞動力,提高施工效率,降低工程費(fèi)用等特點，因此混凝土噴射機(jī)的應(yīng)用越來越普遍。目前已被廣泛地應(yīng)用于鐵路、公路、水利、建筑、煤炭等建筑工程的施工中,成了解決隧道、道路護(hù)坡、建筑基坑、地下工程的臨時和永久支護(hù)理想的施工作業(yè)機(jī)械[ 1 ] 。
1．目前在噴射混凝土作業(yè)中,絕大多數(shù)是使用轉(zhuǎn)子式混凝土噴射機(jī),因為這種噴射機(jī)結(jié)構(gòu)簡單、工作性能可靠、外形小、重量輕、維修和操作方便。干式噴射機(jī)工作原理和結(jié)構(gòu)特征是:帶有襯板的轉(zhuǎn)子以一定的轉(zhuǎn)速旋轉(zhuǎn),而結(jié)合板壓在襯板上固定不動,結(jié)合板上連接有進(jìn)風(fēng)管和出料彎頭,當(dāng)轉(zhuǎn)子中裝有物料的各個料杯轉(zhuǎn)動到與進(jìn)風(fēng)管和出料彎頭相通時,在壓氣的作用下,物料通過出料彎頭和輸料管輸送到噴嘴,并在噴嘴處加水噴射出去。
干式混凝土噴射機(jī)的主要優(yōu)點是輸送距離長、設(shè)備簡單、耐用,但由于它是使干拌和混凝土噴嘴外與水混合,故而施工粉塵,回彈均較大,干噴作業(yè)產(chǎn)生的粉塵危害工人健康,尤其是窄小巷道工程施工中,粉塵污染更為嚴(yán)重[ 2 ] 。
從20 世紀(jì)60 年代起,在西方發(fā)達(dá)國家中,濕噴技術(shù)開始逐漸推行,各種濕式混凝土噴射機(jī)也陸續(xù)開發(fā)出來,與干法噴射混凝土的主要區(qū)別在于足量(按水灰比要求應(yīng)加的量) 拌合水的加入時機(jī)不同;濕式噴射混凝土是在其進(jìn)入輸料管前混合料中已加了足量的拌合水,輸料管中輸送的是全濕混凝土;干式噴射混凝土是在輸料管中輸送未加入拌合水的干料(地面自然濕度拌合料或烘干料) ,而在噴嘴前再加足夠量拌合水,與干混合料迅速混合為全濕混凝土后輸送至噴嘴處,經(jīng)摻加速凝劑后形成料束噴至施工面[ 3 ] 。
在國內(nèi),隨著人們環(huán)保意識的增強(qiáng)以及對噴射混凝土質(zhì)量要求的提高,已有越來越多的濕式混凝土噴射機(jī)進(jìn)入使用。近幾年來,國內(nèi)一些單位也開始開發(fā)研制出幾種濕式混凝土噴射機(jī),但生產(chǎn)規(guī)模尚有待于擴(kuò)大。概括起來,濕式混凝土噴射機(jī)的主要優(yōu)點有以下幾方面:
1) 大大降低了機(jī)旁和噴嘴外的粉塵濃度,消除了對工人健康的危害。
2) 生產(chǎn)率高。干式混凝土噴射機(jī)一般不超過53 m3/ h ,而使用濕式混凝土噴射機(jī),人工作業(yè)時可達(dá)103 m3/ h ,采用機(jī)械手工作業(yè)時,則可達(dá)203 m3/ h。
3) 回彈度低。干噴時,混凝土回彈度可達(dá)15 %～50 % ,采用濕噴技術(shù)回彈率可降低到10 %以下。
4) 濕噴時,由于水灰比易于控制,混凝土水化程度高,故可大大改善噴射混凝土的品質(zhì),提高混凝土的勻質(zhì)性。
2 濕式混凝土噴射機(jī)的種類及工作原理
隨著混凝土濕噴技術(shù)的應(yīng)用,各國分別開發(fā)出一系列的濕式混凝土噴射機(jī)根據(jù)濕式混凝土噴射機(jī)的工作原理,可分為泵送型及氣動型兩大類[ 3 ] 。
2. 1 泵送型濕式混凝土噴機(jī)
泵送型混凝土噴射機(jī)主要有柱塞泵式濕噴機(jī)和螺桿泵式濕噴機(jī)兩類。柱塞泵式濕噴機(jī)是將柱塞式混凝土泵作為濕式混凝土噴射機(jī)的基本機(jī)體,在輸送管出口裝以噴嘴并在此通入壓縮空氣,將混凝土噴射出去,這類濕噴機(jī)一般較笨重,但輸送距離長,在二灘、小浪底等一些大型水利工程中使用,該機(jī)型的主要缺點是生產(chǎn)率低,螺桿和定子套的磨損較嚴(yán)重,故而應(yīng)用范圍不大。
2. 2 氣送式濕式混凝土噴機(jī)
這類濕噴機(jī)是利用壓縮空氣將物料在軟管中以“稀薄流”的形式輸送至噴嘴直接噴出,該機(jī)為并排的兩個罐,一個噴射,一個備料,罐的底部各有一個橫臥的螺旋輸送器,噴射罐內(nèi)通入壓縮空氣,濕拌合料經(jīng)螺旋送進(jìn)輸料管,在噴嘴處,通過氣環(huán)引入的壓縮空氣使拌合料噴射出去,機(jī)動性差。
3 國產(chǎn)濕式混凝土噴射機(jī)
3. 1 SPZ26 型濕式混凝土噴射機(jī)
SPZ26 型濕式混凝土噴射機(jī)是一種氣送轉(zhuǎn)子式濕式混凝土噴射機(jī),其工作原理與瑞士阿利瓦280 機(jī)型相似,其轉(zhuǎn)子由電動機(jī)經(jīng)減速器帶動旋轉(zhuǎn),該機(jī)設(shè)備投資少,生產(chǎn)率高,重量輕,機(jī)動性好[ 4 ] 。
3. 2 PZ25B 型混凝土噴射機(jī)該機(jī)適用于干噴、潮噴和濕噴。它能自動清洗,不粘堵,下料速度快,余料少,效率高。
3. 3 葉輪式濕式混凝土噴射機(jī)
葉輪式濕式混凝土噴射機(jī)是一種新型濕噴機(jī),它采用了一種葉輪喂料裝置,具有工作可靠、使用壽命長、適應(yīng)骨料粒徑范圍大等優(yōu)點。目前我國研制的混凝土泵送和濕噴兩用機(jī)混凝土濕噴機(jī)是隧道施工中不可缺少的工程設(shè)備,目前主要有葉輪式、轉(zhuǎn)子活塞式及泵式濕噴機(jī)。葉輪式和轉(zhuǎn)子活塞式濕噴機(jī)的輸送距離短、排量小、易損件壽命短、漏漿嚴(yán)重、清洗時間長[ 5 ] 。
4 濕式混凝土噴射機(jī)推廣應(yīng)用中需解決的一些問題
目前,由于濕噴技術(shù)具有明顯的優(yōu)勢,濕式混凝土噴射機(jī)在工程中的應(yīng)用亦越來越多,但是,由于存在著一些尚待解決的問題,對濕式混凝土噴射機(jī)的推廣應(yīng)用起到了一定的阻礙作用,以至于在我國,目前主要的噴射混凝土作業(yè)方式仍是干噴。
1) 濕式混凝土噴射機(jī)多采用液體速凝劑,進(jìn)口及合資產(chǎn)品售價較高(達(dá)6 000 元/ t～8 000 元/ t ) ,而國產(chǎn)液體速凝劑尚無生產(chǎn),相對應(yīng)的干噴粉狀速凝劑售價低(1 000 多元/ t) 。
2) 勞動力成本低及人們的環(huán)保意識尚待提高。
3) 濕式混凝土噴射機(jī)作業(yè)時,設(shè)備較為復(fù)雜,操作及維修不及干噴機(jī)方便。
4) 使用濕式混凝土噴射機(jī)作業(yè)時,設(shè)備投資較高。
5 噴射混凝土機(jī)的改進(jìn)
5. 1 改進(jìn)后混凝土噴射機(jī)的特點
1) 防塵效果更好。采用改進(jìn)后的密封裝置可以做到不揚(yáng)塵,大大改善了工人的勞動條件,提高了勞動生產(chǎn)率。
2) 增加防粘結(jié)高彈性橡膠料腔?？捎行Ы鉀Q混凝土易粘結(jié)的問題,減少了清除混凝土粘結(jié)的次數(shù),提高了勞動效率。
3) 運(yùn)用耐磨橡膠墊。橡膠墊的耐磨性提高一倍以上,減少了橡膠墊的更換次數(shù)降低了使用成本。
4) 將原傳動軸由整體改為三部分組成,解決了不易拆卸、維修難的問題。
5. 2 改進(jìn)前后混凝土噴射機(jī)的區(qū)別
1) 原混凝土噴射機(jī)旋轉(zhuǎn)體由耐磨鑄鐵鑄造而成,未經(jīng)處理,生銹后易粘結(jié),改進(jìn)后將噴射腔進(jìn)行噴涂防銹處理,大大降低了粘結(jié)的可能性。
2) 原混凝土噴射機(jī)旋轉(zhuǎn)體直接與出料口接觸,密封不嚴(yán);進(jìn)料口無密封裝置,改進(jìn)后增加一層耐磨橡膠墊并在進(jìn)料口加密封圈。
3) 在旋轉(zhuǎn)體上和噴射口增加高彈性橡膠料,而原混凝土噴射機(jī)旋轉(zhuǎn)體和噴射口無高彈性橡膠腔?；炷羾娚錂C(jī)工作時形成高壓空氣腔,高彈性橡膠腔在空氣的壓力下被壓縮,旋轉(zhuǎn)體是不停轉(zhuǎn)動的,當(dāng)旋轉(zhuǎn)體上的高彈性橡膠腔轉(zhuǎn)過壓力區(qū)后,壓力消失,高彈性橡膠腔將在自身的彈力作用下恢復(fù)原狀,而使附著在高彈性橡膠腔上的混凝土受到擠壓而散落下來,自動清除了混凝土粘結(jié),同時為了便于維修和更換旋轉(zhuǎn)體上的高彈性橡膠料腔,將整體十二個腔分割成四件,每件三個腔。同樣道理,在出料口增加一高彈性橡膠料腔。
4) 原混凝土噴射機(jī)傳動軸為整體結(jié)構(gòu),清理旋轉(zhuǎn)體上的工作腔或更換高彈性橡膠料腔時,須將上座體和篩體同時卸掉才可,改進(jìn)后將整軸分為三部分,中間加一連接軸,通過方母,連接軸,銷軸將兩軸連在一起,拆卸時只須拆掉連接軸就可以將中座體抬起,更換高彈性橡膠腔或者清理旋轉(zhuǎn)體,省時又省力,通過增加橡膠密封墊高彈性橡膠腔以及將傳動軸改為分體連接式結(jié)構(gòu),有效地解決了揚(yáng)塵和混凝土粘結(jié)及拆卸不便的問題,從一些使用現(xiàn)場來看,取得了良好的效果。
6 結(jié)語
采用潮噴工藝雖然可降低粉塵濃度和減少回彈率,但粉塵的危害依然存在,回彈率仍然較高,距要求的標(biāo)準(zhǔn)還有相當(dāng)大的距離。世界各國在探討濕法噴射混凝土工藝的同時,研制了濕式混凝土噴射機(jī),并日趨成熟,許多國家已開始大量采用。我國目前濕噴法仍處在試驗研究階段,還未達(dá)到全面推廣的應(yīng)用水平。主要是濕噴機(jī)體積龐大,工藝復(fù)雜,對集料要求高,而我國生產(chǎn)的液體速凝劑、外加劑性能較差,影響了濕式噴射機(jī)的推廣和應(yīng)用。在這方面我國很多單位已經(jīng)開始了研究,并取得了不小的進(jìn)展[ 7 ] 。研制性能可靠、體積小,可供現(xiàn)場推廣使用的濕噴機(jī)仍是今后噴射混凝土技術(shù)的主攻方向之一。
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