A6410 EMERSON机械膨胀装置

A6410 EMERSON机械膨胀装置

活塞型
使气体在可变容积中膨胀，输出外功制冷的膨胀机(通常由电动机制动吸收外功)。这种膨胀机分立式和卧式两种。采用较多的是立式结构，曲轴、连杆、十字头、活塞、进气阀和排气阀等是运动件，分别装在机身、气缸和中间座中，其作用近似于往复活塞压缩机，但其进、排气阀系借进、排气凸轮定时启闭。活塞膨胀机由于存在进、排气阀流动阻力、不完全膨胀、摩擦热、外热与内部热交换等引起的冷量损失，一般绝热效率为:高压膨胀机65~85%，中压膨机60~70%。20世纪50年代相继出现的不用凸轮传动机构的无阀和单阀膨胀机，减少了膨胀机的运动件，提高了机器运转可靠性，已在小型深低温设备上得到广泛的应用。60年代，采用加填充剂的聚四氟乙烯密封元件代替用油润滑的金属制密封元件，避免润滑油带入深低温精馏区或液化区，保证了安全。
透平型
透平型膨胀机原理图
以气体膨胀时速度能的变化来传递能星的膨胀机。这种膨胀机有单级和双级、立式和卧式、冲动式和反动式之分。一般采用单级向心径流反动式，传出的外功由发电机、鼓风机或油制动器所吸收。它近似于单级离心压缩机，但具有调节进气量用的(可调叶片）导流器。低速轴承用油强制润滑，高速的采用气体轴承。透平膨胀机由于有喷嘴损失、叶轮损失、余速损失、轮盘摩擦损失、泄漏损失、窜流损失和外热侵入损失，一般绝热效率为:中压膨胀机65~75%，低压膨胀机75~85%。60年代已制成带液膨胀机，大多用于天然气分离设备。

A6410 EMERSON机械膨胀装置

Piston type
An expander that causes gas to expand in a variable volume to output external work for cooling (usually absorbed by motor braking). The expansion machine is divided into vertical and horizontal two kinds. The most used is the vertical structure, crankshaft, connecting rod, cross head, piston, intake valve and exhaust valve are moving parts, respectively installed in the body, cylinder and middle seat, its role is similar to reciprocating piston compressor, but its intake and exhaust valve is open and close by the inlet and exhaust CAM. Piston expander due to the existence of inlet and exhaust valve flow resistance, incomplete expansion, friction heat, external heat and internal heat exchange caused by cold loss, the general adiabatic efficiency is: high pressure expansion machine 65~85%, medium pressure expansion machine 60~70%. In the 1950s, valveless and single-valve expanders without CAM transmission mechanism appeared successively, which reduced the moving parts of the expander and improved the operation reliability of the machine, and has been widely used in small deep-temperature equipment. In the 1960s, polytetrafluoroethylene sealing elements with filler were used instead of oil-lubryed metal sealing elements to avoid lubricating oil being brought into the deep-temperature rectification area or liquefaction area to ensure safety.
Turbine type
Schematic diagram of turbo-type expansion machine
An expander that transmits energy stars by changing the velocity energy of the gas as it expands. The expander is divided into single stage and double stage, vertical and horizontal, impulse and reaction type. Generally, single-stage radial flow reaction type is used, and the outgoing external work is absorbed by the generator, blower or oil brake. It is similar to a single-stage centrifugal compressor, but has a (adjustable blade) deflector for regulating the intake volume. Low speed bearing oil forced lubrication, high speed using gas bearings. Turbine expander due to nozzle loss, impeller loss, residual speed loss, disc friction loss, leakage loss, channeling loss and external thermal intrusion loss, the general adiabatic efficiency is: 65~75% of the middle pressure expansion machine, low pressure expansion machine 75~85%. In the 1960s, it was made into a liquid expansion machine, mostly used in natural gas separation equipment.

A6410 EMERSON机械膨胀装置