A6410  EMERSON 机械膨胀装置

A6410

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 by changing the velocity energy of a 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.