制冷与yu空调专业英语.ppt

1-* 制冷空调专业英语 Unit Three * 制冷空调专业英语 Unit Three Lesson 9 Control Valves Lesson 10 Liquid Pump Lesson 11 The Reciprocating Compressor Lesson 12 Heat Exchanger Lesson 11 New Words Expressions: 包括一切的，全面的 single-stage adj. 单级的，单段的 multistage adj. 多级的 double-acting adj. 双动的 actuate vt. 开动, 促使 isoentropic adj. 等熵的 thermodynamic adj. 热力学的, friction n. 摩擦, 摩擦力 inefficiency n. 无效率, 无能 over-all adj. Text The reciprocating compressor can furnish gas at pressures of a few pounds or at extremely high pressures, such as 35,000 psi. 1 The characteristic features of reciprocating compressors are the same as those of reciprocating pumps ─ a piston, a cylinder with suitable intake and exhaust valves, and a crank-shaft with drive. Every compressor is made up of one or more basic elements. A single element, or a group of elements in parallel, comprises a single-stage compressor. 往复式压缩机能提供几磅压强的气体或压力极高（达35，000磅∕英寸）的气体。往复式压缩机的典型特征是和往复泵一样的，它们都具有活塞、气缸（气缸具有合适的进气阀和排气阀）和驱动曲柄轴。压缩机由一个或多个这些元件组成。单个或几组元件并行则构成单级压缩机。 Lesson 11 Text: Many compression problems involve conditions beyond the practical capability of a single compression stage. Too great a compression ratio may cause excessive discharge temperature or other design problems. Lesson 11 许多的压缩问题，超出了单级压缩的范围。因为压缩比过大，会导致排气温度过高，或者会引起其他设计问题。 Text: It therefore may become necessary to combine elements or groups of elements in series to form a multistage unit, in which there will be two or more steps of compression. Single-stage or multistage operation is common, with double-acting cylinder usage being general.2 Lesson 11 因此，就必须使多组元件串联成多级压缩，它的压缩过程由二步或多步来完成。常见的是单段操作或多段操作，并且一般采用双作用气缸。。 Text: Gas being compressed enters and leaves the cylinder through valves which are set to be actuated when the pressure difference between cylinder contents and outside conditions is that desired3. Inlet valves open when the pressure in the cylinder is slightly below the inta