制冷毕业设计(论文)

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摘要

钢铁厂在生产出成品钢材后必须在短时间内将其卖出，使用钢材的单位在购入钢材后需要及时的对钢材表面进行处理，达到防锈的目的。实践表明，钢材表面不做任何防锈处理，7到10天左右，表面就开始出现锈点，之后会以这些锈点为核心，表面快速生锈，进而锈蚀到内部，影响钢材性能。

在现阶段，钢材市场比较萎靡，很多钢材厂家面临着困境：生产出钢材短期内卖不掉，时间长了就会生锈，不生产钢材，就面临着倒闭。基于此种状况，一种钢铁表面防锈剂被开发了出来，此种药剂可在钢材上冷床之前喷在其表面，达到防锈目的，一般情况下，防锈时间可以达到未处理钢材的8倍左右，这样就能为钢材厂家提供足够的缓冲时间，同时，表面不生锈也能成为其一大卖点。

然而处理钢材表面是在进入冷床冷却之前，其表面温度达到450℃左右，回收的处理液温度也会很高，导致整个药箱内温度不断提升，最终会使防锈剂碳化失效，因此，需要对药箱进行降温。

本课题的目的就在于设计出的制冷系统能使得要向内部温度恒定，制冷量必须和余热量平衡，且随着钢材生产速度变化，制冷量也能够相应自动控制。

关键词：制冷系统双温双控自动控制系统

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ABSTRACT

Steel plant must sell the finished steel products in a short period of time, the units which use steel require timely processing of steel surface in the purchase of steel products, achieving the purpose of rust. Practice shows that the rust points on the steel surface with no rust treatment began to appear in 7 to 10 days. Then the steel surface rust rapidly taking the rust points as core, even corrode the internal steel, which impact properties of steel.

At present, the steel market is sluggish. Many steel manufacturers are faced with a dilemma: if producing steel products can not sell out in the short term, it will rust after a long time, if not producing steel, the Steel plant is faced with collapse. Based on this condition, a rust inhibitor for steel surfaces has been developed, this potion can spray on the surface before the steel cooling bed, so as to achieve anti-rust purposes, under normal circumstances, the anti-rust time can be achieved around eight times as long as untreated steel, so that it can offer enough buffer time for steel manufacturers, at the same time, the surface being not rust can become one big selling point.

Steel surface is, however, before entering the cooling bed, the surface temperature reaches 450℃or so, and the collection of fluid temperature will be also very high, which lead to rising temperature in the whole cabinet. Eventually that will make anti- rust inhibitor carbide lose efficacy. Therefore, they need to cool medicine cabinet.

The purpose of this subject is to design the refrigeration system that can make the internal temperature of medicine cabinet constant , refrigerating capacity and residual heat must be in a balance. What is more, with changes in the rate of steel production, the refrigerating capacity can be also a corresponding automatic control.

Keywords: refrigeration system; double temperature double control; automatic control system

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目录

1 绪论 (1)

1.1课题研究目的 (1)

1.2制冷机简介 (1)

1.2.1工作原理 (2)

1.2.2制冷机的种类 (3)

1.2.2.1压缩式制冷机 (3)

1.2.2.2吸收式制冷机 (4)

1.3小型制冷机发展现状及新技术 (4)

1.3.1压缩机 (4)

1.3.2换热器 (5)

1.4小型制冷机自动测试系统的组成 (5)

1.5制冷机的启动 (6)

1.5.1 压缩机电机工作原理 (6)

1.5.2 单相电机常用启动型式 (6)

1.5.2.1 电阻分相启动(RSIR) (6)

1.5.2.2 电容分相启动(CSIR) (6)

1.5.2.3 电容启动、电容运转型(CSR) (7)

1.5.3 现有启动方式比较及其与启动继电器的配合 (7)

1.5.3.1 三种启动方式比较 (7)

1.5.3.2 与启动继电器的配合 (7)

1.5.3.2.1 弹力式启动继电器 (7)

1.5.3.2.2 重锤式启动继电器 (7)

1.5.3.2.3 PTC 启动继电器 (8)

1.6制冷机的腐蚀与保护 (8)

1.7制冷机低温泵的故障及排除 (9)

1.8关于小型制冷装置的模拟研究 (11)

1.9小型制冷机的发展方向 (11)