混辗式混砂机机械结构设计
喜欢就充值下载吧。资源目录里展示的文件全都有,请放心下载,有疑问咨询QQ:414951605或者1304139763 = 喜欢就充值下载吧。资源目录里展示的文件全都有,请放心下载,有疑问咨询QQ:414951605或者1304139763 =
编号无锡太湖学院毕业设计(论文)相关资料题目: 混辗式混砂机机械结构设计 信机 系 机械工程及自动化专业学 号: 0923203学生姓名: 宦乾元 指导教师: 范圣耀 (职称:副教授 ) 2013年5月20日目 录一、毕业设计(论文)开题报告二、毕业设计(论文)外文资料翻译及原文三、学生“毕业论文(论文)计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计(论文)开题报告题目: 混辗式混砂机机械结构设计 信机 系 机械设计及自动化 专业学 号: 0923203 学生姓名: 宦乾元 指导教师: 范圣耀 (职称:副教授 ) 2013年5月15日 课题来源无锡宜兴某工程设备有限公司科学依据(包括课题的科学意义;国内外研究概况、水平和发展趋势;应用前景等)(1)课题科学意义混砂机是使型砂中各组分均匀混合,并使黏结剂有效地包覆在砂粒表面的设备。混砂机(sand mixer)利用碾轮与碾盘的相对运动,将置于两者间的物料受到碾压兼磨削的作用而粉碎物料,混砂机在粉碎物料的同时还将物料混合。是生产免烧砖、灰砂砖、水泥砖、耐火砖、粉碎和混合粉煤灰、锅炉炉渣、尾矿渣及工业废渣作制砖原料的理想设备。(2)混砂机的研究状况及其发展前景混砂机在粉碎物料的同时还将物料混合。是生产免烧砖、灰砂砖、水泥砖、耐火砖、粉碎和混合粉煤灰、锅炉炉渣、尾矿渣及工业废渣作制砖原料的理想设备。混砂机是砂处理系统的主要设备。混砂机碾轮长时间在粘土砂中碾转工作,其碾轮轴承经常由于密封不好而损坏,影响碾砂工作效率。混辗式混砂机配置具有一定重量的辗轮,混砂时辗轮既能围绕混砂机的主轴公转,又能围绕辗轮轴自转。辗轮在辗压的同时搓研型砂,使型砂颗粒覆上一层黏结剂的薄膜。混制面砂和芯砂时,混砂质量优於其他混砂机。50年代初曾有用弹簧加压的混辗式混砂机。由于采用弹簧加压,辗轮自重减轻,可用较高的主轴转速,同时辗压力可以随被辗压砂层的厚度自动调节,从而保证混砂效果均匀一致,提高了混砂的效率。有如下的特点:1、根据脂硬化水玻璃砂工艺要求精心选择液料过滤器、计量泵、阀,确保流量稳定可靠。2、该机在混砂时直接加入水玻璃和有机脂,经高速混制,混制好的砂子能在短时间内自硬,省去吹二氧化碳的步骤。3、搅刀镶有硬质合金刀头,独特结构设计,能使砂子和水玻璃混制均匀,确保水玻璃均匀涂覆在砂子表面。4、电气采用PLC控制,模拟显示,工作稳定可靠,实现自动化生产。5、采用连续混砂机构设计,能极大提高混砂速度,拥有大回转半径的大臂,满足了大型铸件砂子的快速填充。6、特殊的粘结剂加料系统和型砂出料口设计,配以精确的控制,混砂机启动停止过程中可实现基本无头尾砂损失。这些是特点的不断提升,和智能化的融合是混砂机的发展的必然方向。混出的型砂也会质量越高,数量越多,操作越简单,维护越方便。研究内容1.如何满足混砂机传动装置传动比和承载能力要求;2.使得混砂机的卸砂门的气动机构的气缸少,投资小,机构简单;3.使得混砂机的控制部件实现简单的PLC控制;4.要使减速机具有结构简单,成本低,易于制造,安装、调整要求低,运行维护方便,可靠性更强的特点。拟采取的研究方法、技术路线、实验方案及可行性分析(1)研究方案寻找成熟的结构,进行传动机构的方案变更,加入PLC的控制和选择设计适应的汽缸,从而使其更加方便,高效,便宜。(2)研究方法 1.阅读相关的材料,记录相关的要点;2.根据专业课的所学进行CAD画图,PLC设计,传动机结构的计算以及汽缸选择。研究计划及预期成果研究计划:2012年11月12日-2012年12月25日:按照任务书要求寻找并查阅论文相关参考资料,填写毕业设计开题报告书。2012年12月11日-2013年3月5日:寻找相关的英语资料,并学习研究翻译资料。2013年3月8日-2013年3月14日:构思论文结构,和需要的图纸,并要求修改毕业设计开题报告。2013年3月15日-2013年3月21日:学习并翻译一篇与毕业设计相关的英文材料。2013年3月22日-2013年4月11日:混砂机原理和大体结构,确定需要的参数和数据。 画除传动外的机械图。 2013年4月12日-2013年4月25日:传动与汽缸部分的选择,设计并计算,并画图。2013年4月26日-2013年5月21日:整合以上的资料,撰写毕业论文。预期成果:不仅要满足混砂机传动装置传动比和承载能力要求,而且要使减速机具有结构简单,成本低,易于制造,安装、调整要求低,运行维护方便,可靠性更强的特点。和汽缸结构的特色或创新之处 提高功率,混砂质量,使用时间,功能稳定。具有承载能力大,效率高等突出优点;混砂机重量、外形尺寸减小,整机性能提高。已具备的条件和尚需解决的问题 已有相应的资料。有减速传动的课程设计经验。 混砂机设计各部分之间如何灵活,协调配合性能可以整体提升。指导教师意见 指导教师签名:年 月 日教研室(学科组、研究所)意见 教研室主任签名: 年 月 日系意见 主管领导签名: 年 月 日英文原文英语原文Sand mixerAbstract:A foundry sand mixer for mixing and dispensing silica or green sand and their additives through the enclosed longitudinal belt conveyor mechanism having a plurality of openings in the top communicating with a first feeder disposed above the enclosed longitudinal belt conveyor mechanism and including a pair of openings in the bottom. The first feeder includes an auger-type conveyor and a sand weir communicating with the most upstream opening in the first feeder. A first hopper for containing silica sand and a second hopper for containing green sand are disposed over the first feeder. A selective valve is disposed at the bottom of each of the first and second hoppers permitting the flow of sand through only one of the hoppers at any time or preventing the flow of any sand from the hoppers. The mixer may include additional feeders, some of which are disposed above and downstream from the first feeder, and others including pumps are connected to a plurality of fluids that are fed through a constant speed mixer where the materials are mixed and the mixed materials delivered at a discharge opening. Inventors:Frankie, Donald M. (1599 Gull La., Mound, MN, 55364)Claims: 1. In a foundry sand mixer for mixing and dispensing silica or green sand and their additives, the combination comprising: (a) a support frame pivotal about a vertical axis and having a platform extending radially therefrom; (b) an enclosure including an enclosed longitudinal belt conveyor mechanism extending above said platform and having a plurality of openings in the top of the enclosure communicating with said belt conveyor mechanism; (c) first feeder means disposed above and at the most upstream location of said enclosed longitudinal belt conveyor mechanism, said first feeder means having a bottom and converging sloping sides communicating near the bottom with an auger-type conveyor, and having a pair of openings longitudinally separated in the bottom thereof feeding said belt conveyor;(d) a sand weir communicating with the most upstream opening of said pair of openings in said first feeder means, said sand weir disposed above said longitudinal belt conveyor mechanism for dispersing sand on said belt conveyor mechanism; (e) a first hopper for containing silica sand disposed over the upstream portion of said first feeder means;(f) a second hopper for containing green sand disposed downstream from said first hopper and over said first feeder means; (g) selective valve means disposed at the bottom of each of said first and second hoppers permitting the flow of sand through only one of said hoppers at any time or preventing the flow of any sand from said hoppers; (h) and control means operably connected to said selective valve means for selecting one of said two sands or neither to be dispensed onto said belt conveyor.2. The structure set forth in claim 1 including: (i) a plurality of second feeder means disposed above said belt conveyor mechanism and at a downstream location from said first feeder means, each of said plurality of second feeder means having a bottom and converging sloping sides communicating near the bottom with an auger-type conveyor and having an opening in the bottom thereof feeding said belt conveyor; (j) a constant speed mixer disposed on said platform and arranged to receive granular and liquid materials, mix the materials and deliver the mixed materials at a discharge opening, said belt conveyor communicating with said mixer; (k) and a plurality of pump means connected to a plurality of fluids and communicating with said mixer.Description: This invention relates to the field of mixers and more particularly to the field of foundry sand mixers for mixing silica or green sand and their additives. BACKGROUND OF THE INVENTION While the art of mixing foundry sand per se through a mechanical process is generally known, there are attendant problems in attempting to use the same equipment for mixing green sand and its additives as generally might be used in a mixer using silica sand and its additives. Because of the inherent differences in the materials to be mixed and passed through the machine, the practice has generally been to use separate machines for each of the different foundry sand materials and processes. SUMMARY OF THE INVENTION The embodiments of this improvement invention makes it possible to combine the necessary equipment into a single machine to mix either green sand or silica sand and their additives. Various means have been attempted to mix green sand which requires the addition of such other granular and dry ingredients as fire clay, bentonite, sea coal, pitch, wood flour and the like, along with an appropriate mixture of water. On the other hand, silica sand, which may also be known as a no-bake sand, is generally mixed with dry granular materials such as chromite and ferric oxide and several liquid ingredients which may include certain chemicals. Because certain green sand molds may be broken down after use and reused, green sand, when mixed with such components, provides a different flow pattern than that of silica sand. Silica sand flows through hoppers and equipment much like the flow of water whereas green sand has additional additives and mixtures that generally make it lumpy with attendant flow problems. Various means have been devised in the past to make a slurry of the additives and add them to the green sand but the mechanism does not prove to be useful in working with both types of molding sand. One such mechanism is that disclosed in U.S. Pat. No. 3,070,858 issued to J. S. Beacon. It is also known that certain silica sand or no-bake sand mixers have been available but are not operable to run green sand through them and mix the green sand in the manner generally attributable to silica sand. One such disclosure of a mechanism of this type is found in U.S. Pat. No. 3,682,448 isued to Kedzior et al. The present invention is an improvement upon the mechanism disclosed in my earlier U.S. Pat. No. 4,140,246 entitled PROPORTIONAL CONTROL SYSTEM FOR FOUNDRY SAND MIXING DEVICE. It is therefore a general object of the present invention to provide an improvement in foundry sand mixing equipment. It is a more specific object of this invention to provide a foundry sand mixer that will mix either silica sand or foundry green sand and their additives. It is yet another object of this invention to provide a foundry sand mixer in which either silica sand or foundry green sand is controlled by a valve mechanism selectively depositing one or the other on a belt conveyor for proper mixing. These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which: FIG. 1 is a perspective view of the invention; FIG. 2 is a schematic diagram of the mixer control circuit; FIGS. 3A and 3B are schematic diagrams of the drive circuits for all of the variable speed motors driving feeders and pumps in the invention; FIG. 4 is a diagram of the control panel on the end of the mixer; and FIG. 5 is a schematic diagram of the selective sand valve. PREFERRED EMBODIMENT Reference is now made to FIG. 1 wherein the foundry sand mixer 10 is disclosed. The mixer is secured to a base 11 that has a vertical axis about which a housing 12 pivots, housing 12 having a cantilever beam 13 extending radially therefrom. At the upstream end of the mechanism, a bracket 14 supports one end of an enclosed conveyor mechanism 15 and the other end of conveyor mechanism 15 is supported by a chute 16 that acts as a support bracket that is indirectly secured to beam 13. A belt conveyor 17 is disposed within the housing 15 and is supported for movement by a plurality of horizontal transversely oriented rollers 20. A direct current drive motor 21 is connected to the downstream end roller to drive the belt conveyor mechanism 17. Disposed above the enclosed conveyor 15 is a first feeder 22 which is elevated slightly above the conveyor enclosure 15. Feeder 22 is in the nature of a container having sloping sides converging at the bottom with an auger-type conveyor 23 driven by a variable speed motor 24. Feeder 22 has its sides extending upwardly at an angle of approximately 30 degrees with a vertical and it has been found that if the sides extend outwardly so that the angle with the vertical is approximately 45 degrees, flow of the green sand will be encumbered. Feeder 22 has two openings in the bottom thereof, the first terminating in a sand weir 25 which is at the upstream location with respect to the longitudinal dimension of the feeder and is directly beneath a silica sand hopper 26. Disposed downstream from said weir 25 is a tubular member 27 that communicates between an opening 30 in the bottom of first feeder 22 and the top of the enclosed conveyor mechanism 15. Disposed across the opening 30 is a scarifier 31 in the nature of two right angle diametrically oriented rods that are used to break up any lumps that may still exist upon being conveyed to that opening by auger conveyor 23. Silica sand hopper 26 is disclosed as being generally rectangular in shape having a common side 32 which acts as a separator with another hopper 33 that is used to contain green sand. The sides of the hoppers slope downwardly in a converging manner and are terminated in a pair of chutes 34 and 35. A selective valve 36 is disposed across the openings of chutes 34 and 35 so that upon movement to the right (as seen in FIG. 1) sand will flow from hopper 26 through chute 34 into first feeder 22 but block flow of sand through chute 35 and upon movement to the left, valve means will permit flow of green sand from hopper 33 through chute 35 but block the movement of silica sand. In other words, either silica sand or green sand is admitted during the two extreme movements and while the valve is in its center position, sand is restricted from movement into either chute 34 or 35. Selective valve 36 is controlled by an air cylinder 37 that has a piston rod 38 connected to valve 36 through a linkage 40. A solenoid actuated valve 41 is connected to a source of pressurized air 42 through a pneumatic line 43. The source of air under pressure is generally 100 psi for good operating conditions. A pair of pneumatic lines 44 and 45 connect solenoid valve 41 with air cylinder 37 and the solenoid coils are controlled through an electrical circuit connected to the solenoid valve 41. A 110 volt source is connected through a common lead 46 to solenoid valve 41 and one coil has its return current path through a conductor 47 and one terminal of a single pole double throw switch 50. The switch blade is connected to the other terminal of the 110 volt source through a conductor 51. Another coil in the solenoid valve 41 is connected through the electrical circuit by a conductor 52 connected to another terminal of switch 50. As disclosed in FIG. 5, when the switch blade is connected with conductor 47, the silica sand or no-bake sand is permitted to pass through valve mechanism 36 and when the other portion of the solenoid valve is actuated through conductor 52, the green sand is permitted to pass through valve 36. A second feeder 53 is disposed above the conveyor enclosure 15 downstream from first feeder 22. Second feeder 53 has the same general shape and configuration as that of first feeder 22 and includes a conveyor auger 54 driven by a variable speed motor 55 through a pair of sprockets 56 and 57 and a chain 58. Second feeder 53 has an opening in its bottom near the downstream end of auger conveyor 54 which is coupled to the housing 15 through a tubular member 60. Disposed above the auger conveyor 54 is a stirrer 61 that is in the form of shaft extending parallel to the shaft of the auger conveyor 54 and having a plurality of branches or arms extending therefrom, which when the assembly is turned tends to break up any bridges or lumping of materials such as bentonite or sea coal. A pair of sprockets and a chain drive stirrer 61 form the shaft of auger conveyor 54. A third feeder 62 is disposed downstream from second feeder 53 and is generally identical for the most part to that of second feeder 53. Feeder 62 also contains an augur-type conveyor 63 driven by variable speed motor 64 with a tubular section 65 connecting the opening in the bottom of the feeder through an opening in the top of conveyor housing 15. Disposed at the bottom of the housing or compartment 12 is a pair of liquid containers 70 and 71 which may contain chemicals or may contain water, depending upon the type of additive to be made to the particular sand which is being mixed. Container 70 is connected to a pump 72 through a pipe 73 communicating with container 70 and an outlet line 74 is connected to pump 72. In a similar manner, a pump 75 is connected to fluid in container 71 through a pipe 76 and the outlet of pump 75 is dispensed through a pipe or line 77. A pair of variable speed motors 80 and 81 is respectively connected to pumps 72 and 75 to dispense the liquids contained in containers 70 and 71. The variable speed motors described are conventional variable speed direct current motors and are generally 3/4 H.P. in size. Air cylinder 37 is approximately one and one-half inches in diameter and has a six inch stroke and is manufactured by Lynair under Model No. AB102-6 whereas the solenoid valve 14 is of the type manufactured by Novi, Model 25C4E. A cylindrical mixer 90 is secured to beam 13 by suitable means and has a plurality of paddles 91 carried by a shaft 92 that does the actual mixing. Shaft 92 is connected to a constant speed motor 93 by suitable means such as a coupling or clutch. Chute 16 receives materials from conveyor 17 through an opening formed in the downstream end beyond the end of conveyor 17. The lower end of chute 16 opens into a segment of mixer 90 at the upstream side thereof. Fluid-carrying pipes 74 and 77 are also connected to mixer 90 near the downstream side of the mixer. In FIG. 2, the mixer motor drive circuit is disclosed in which a three phase 220 volt power line applies power through lines L1, L2 and L3 to mixer motor 93 through three relay contacts, all designated mixer starter contacts M1. The 220 volt line is connected to a transformer TR1 where a voltage reduction takes place in the secondary and 110 volt single phase alternating current is obtained and is applied to one line as a common or neutral line 100. A mixer motor relay M1 has its coil connected between line 100 and another line 101 connected to the secondary of transformer TR1 through a normally closed Mixer Stop pushbutton switch 102 and a normally open Mixer Start switch 103. In parallel with switch 103 is another pair of normally open relay contacts M1. Electrical line 101 is extended in a parallel path through another set of relay contacts M1 which are closed upon depressing start switch 103 and upon depressing another normally open pushbutton switch 104 current is applied to a pump motor start relay CR1 that is also connected to neutral line 100. Upon pulling the switch button for switch 104, the circuit is opened. In parallel with switch 104 and control relay CR1 is another normally open double pole pushbutton switch identified as a SAND AND PUMP SWITCH 105, and upon closing connects another control relay CR2 with neutral line 100. Another control relay CR3 is connected in parallel with control relay CR2 through the second set of contacts in switch 105. Control relay CR2 is used to energize all of the pump circuits and control relay CR3 is used to energize all of the feeders that are used to supply additives by the feeders. At the bottom of the circuit is shown the sand selector switch 50 that is connected to the solenoid coil of solenoid valve 41, causing the valve to be actuated and apply fluid under pressure to the cylinder to cause the movement of valve 36. Turning now to FIGS. 3A and 3B, the electrical schematic of the variable speed drive motors will now be described. Alternating current of 230 volts single phase is applied through a switch 106 to each of the different mechanisms that may be in addition to the belt conveyor, feeders or pumps. A discussion of a portion of the circuit will be germain to the remainder where the various circuits and variable speed drive mechanisms are substantially identical to each other. Power is applied to channel 1 and the circuit in association with motor 21. The variable speed drive has a feed back circuit which works through a toothed wheel 107 that is sensed by a magnetic sensor 108 and the signal supplied to the circuit board 110. Circuit board 110 also has the field connections for the motor connected thereto as well as the armature connections through appropriate relay contacts identified as the relays shown in FIG. 2. Circuit board 110 is further identified as a TF1
收藏