压缩机Compressors(双语)

PRODUCTION TECHNICAL TRAINING
生产培训
PRESENTS
课程介绍
MODULE: Compressors
模块：压缩机
DESIGNED FOR
ENHANCING OPERATIONS KNOWLEDGE & SKILLS
适用于提高操作知识和技能
STUDENT PACKAGE
学生部分
TABLE OF CONTENTS
目录
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I.INTRODUCTION: (6)
I．引言
II.GAS COMPRESSION AND METHODS OF COMPRESSION (6)
II．气体压缩和压缩方法
A.C OMPRESSION B ASICS (6)
A．压缩基本知识
1)Gas Physics (6)
1) 气体的物理性质
2)Centrifugal Compressor Head Curve (7)
2）离心式压缩机压头曲线
B.P URPOSES OF C OMPRESSING G AS IN C HEMICAL P ROCESS S YSTEMS (7)
B．化学工艺系统中压缩气体的目的
C.C OMMON T YPES OF C OMPRESSORS AND T HEIR O PERATION (8)
C．常用类别的压缩机及其运转
III.CENTRIFUGAL AND AXIAL FLOW COMPRESSORS (9)
III. 离心和轴流压缩机
A.C ENTRIFUGAL C OMPRESSORS (9)
A．离心压缩机
1)Uses (9)
1）用途
2)Major Components and Operation (10)
2）主要零部件和运转
B.A XIAL F LOW C OMPRESSORS (10)
B．轴流压缩机
1)Uses (10)
1）用途
2)Design and Operation (11)
2）设计和运转
C.C ENTRIFUGAL C OMPRESSOR S EALING/L UBRICATION AND C OMPONENTS..............
C．离心压缩机密封/润滑和零部件
1)Non-contact Shaft Seals (12)
1）非接触轴封
a)Labyrinth Seal (12)
a）迷宫式密封
b)Ported Labyrinth Seal (3)
b）带排出孔的迷宫式密封
c)Restrictive Ring Seal (4)
c）阻流环密封
2)Contact Shaft Seals (5)
2）接触轴封
a)Mechanical Contact Shaft Seal (5)
a）机械接触轴封
b)Liquid-Film Shaft Seal (6)
b）液膜轴封
c)Overhead Seal Tank (7)
c）高位密封油箱
3)Bearings (8)
3）轴承
a)Journal Bearing (9)
a）支持轴承
b)Thrust Bearing (9)
b）推力轴承
c)Tilting-Pad Journal Bearing (9)
c）可倾瓦块支持轴承
d)Balancing Drums (10)
d）平衡盘
4)Lube-Oil Systems (13)
4）润滑油系统
D.C OMMON O PERATING P ROBLEMS IN C ENTRIFUGAL AND A XIAL F LOW C OMPRESSORS C OMPRESSORS (15)
D．离心和轴流压缩机的常见运转问题
1)Surge Problems (15)
1）喘振问题
a)Causes of Surge (15)
a）喘振原因
b)Methods of Correcting Surge (16)
b）纠正喘振的方法
2)Vibration Problems (16)
2）振动问题
a)Definitions and General Physics (17)
a）定义和一般物理性质
b)Monitoring Systems (20)
b）监视系统
c)Radial Vibration (21)
c）径向振动
d)Axial Displacement (22)
d）轴向位移
e)Temperature (23)
e）温度
f)Vibrating Alarm Systems (23)
f）振动报警系统
g)Transducer-Failure Alarm (24)
g）传感器故障报警
h)High-Radial-Vibration Alarm (24)
h）大径向振动报警
i)Axial-Position Alarm (24)
i）轴向位移报警
j)High-Temperature Alarm (24)
j）高温报警
3)Lube and Seal-Oil Systems and Problems (25)
3）润滑和密封油系统及问题
a)Typical Lube Oil System (25)
a）典型的润滑油系统
b)Typical Seal Oil System (28)
b）典型的密封油系统
IV.POSITIVE DISPLACEMENT COMPRESSORS (30)
IV. 容积式压缩机
A.R ECIPROCATING C OMPRESSORS (30)
A．往复式压缩机
1)Design Characteristics (30)
1）结构特点
2)Double-Acting Reciprocating Compressor (39)
2）双作用往复式压缩机
3)Operation (39)
3）操作
B.R OTARY C OMPRESSORS (40)
B．旋转式压缩机
1)Rotary Sliding Vane Compressors (40)
1）旋转滑动叶片压缩机
2)Rotary Two-Impeller (Lobed) Compressors (41)
2）旋转式双叶轮（叶形轮）压缩机
3)Rotary Screw Compressor (42)
3）旋转式螺杆压缩机
4)Rotary Liquid Piston Compressors (43)
4）旋转液体活塞压缩机
VI.SUMMARY (47)
VI．摘要
I.INTRODUCTION:
引言
Compressors are similar in construction to pumps, but operate on different principles since gases are compressible and liquids are not. The primary purpose of compressors is to move air or gases from one place to another and to increase its pressure. Centrifugal and reciprocating compressors are found in many plants. As a Technician, you must be familiar with the design and basic operation of these pieces of equipment and how gases behave when they are compressed.
压缩机的结构与泵的类似，但以不同的原理运转，原因是气体可压缩，但液体不能。

压缩机的主要用途是使空气或气体从一处移至另一处以提高其压力。

离心和容积式压缩机用于许多装置。

作为一名技术人员，您必须熟悉这些设备的设计和基本运转，以及气体被压缩时的特性。

II.GAS COMPRESSION AND METHODS OF COMPRESSION 气体压缩和压缩方法：
Compressors are essentially “gas pumps.” They are designed to move gases, whereas “pumps” are usually thought of as being designed to move liquids.
压缩机基本上是“气体泵”。

它们被设计用于输送气体，而“泵”通常被视作是设计用于输送液体的。

In the module about pumps, it explains the way that pumps transfer fluids, pressure, head, and flow.
To a great extent, this learning also applies to compression and movement of gases. Two of the major differences related to liquids and gases are:
在有关泵的模块中，解释了泵输送液体的方法、压力、压头、和流量，在很大程度上也适用于气体压缩和运动，有关液体和气体的两个主要区别是：
∙ A liquid has a definite volume and so exerts pressure due to its column height, density, etc., only on the vessel walls or lines contacted by the liquid; whereas a gas fills the available volume and so exerts its pressure on all contacted surfaces.
液体的体积固定，所以因其柱高、密度等，仅对与液体接触的塔器和管线施加压力，而气体充满可供使用的空间，所以将其压力作用于所有接触的表面。

∙ A liquid is not compressible whereas a gas is compressible.
液体不可压缩，而气体可压缩。

pression Basics
压缩基本知识
1)Gas Physics
气体的物理性质：
A gas has no definite form or regular shape and is almost instantaneously distributed and mixed
throughout any closed vessel in which it is placed. A gas consists of individual molecules,
which in a mixture, may vary widely in size. At normal temperatures, the molecules traveling at high speed strike against the enclosing surfaces and produce pressure. As the temperature of
a fixed volume of gas is increased, the speed of the molecules increases, resulting in an
increased pressure.
气体无固定形状或规定外形，几乎立即在其所处于的整个封闭空间内分布和混合。

气体由各个分子
组成，在一混合物中，其大小有极大的变化。

在正常温度下，高速移动的分子撞击封闭表面和形成压力。

随着固定体积的气体温度升高，分子的运动速度加快，导致压力增大。

If a fixed weight of gas is slowly squeezed into less space, molecular travel is restricted to a smaller volume and the pressure is increased because the molecules hit the enclosing surface with greater frequency. If the gas is compressed rapidly by a piston in a cylinder, the
temperature as well as pressure increases as a result of the increase in molecular speed. A simple illustration of this is the bicycle pump which gets hot when it is used to inflate a tire.
如果缓慢地将固定重量的气体挤压进较小的空间，分子运动就限制在一较小的体积内，由于分子以更大的频率撞击封闭表面，所以压力增大。

如果气缸内活塞使气体迅速压缩，温度及压力就因分子速度加快而升高。

这一情况的简单示例是自行车气筒，它在为车胎打气时变热。

Compression may be thought of as the forcing of a confined volume or weight of gas into a smaller space. This is done primarily to increase pressure, but is accompanied by a rise in temperature and an increase in stored energy. These effects may be calculated and compressor performance predicted.
压缩可被视作将有限体积或重量的气体强制送入较小的空间。

它主要用于提高压力，但伴有温度升高和存储能量的增多。

我们可以计算出这个结果并测算出压缩机效率。

2)Centrifugal Compressor Head Curve
离心式压缩机压头曲线：
The basic concepts of centrifugal compressor performance are very similar to those studied in the module covering centrifugal pump performance. There is a head pressure that is the discharge pressure of the centrifugal compressor measured in pounds per square inch (psig).
The flow rate to or from the compressor is often measured in cubic feet per minute (cfm).
离心式压缩机工作性能的基本概念与涉及离心泵工作性能的模块中讨论的基本概念极其相似。

这里有一压头压力，它是实测的离心式压缩机排出压力，单位：磅/平方英寸（psig）。

进出压缩机的流量常常以立方英尺/分钟（cfm）为单位测量。

The centrifugal compressor head curve varies with compressor speed. Higher speed results in higher discharge pressure or head. This curve also has a surge line which is the area or region of low flow through the compressor. A compressor will be damaged if it is operated anywhere beyond the line indicating surge conditions.
离心压缩机压头曲线因压缩机速度而异，较高的速度导致较高的排出压力或压头。

这一曲线还有一喘振线，它是通过压缩机的低流量范围或区域。

如果压缩机在线以外指示喘振条件任何区域运转，它就将损坏。

Horsepower and efficiency are important variables in compressor performance. Rotating equipment specialists and engineers conduct periodic performance tests of large compressors to determine their efficiency and any need for repair work or reconditioning.
功率和效率是压缩机工作性能中的重要变量。

旋转设备专家和工程师定期对大型压缩机执行工作性能试验，以确定其效率和是否需要修理或重新调节。

B.Purposes of Compressing Gas in Chemical Process Systems
化学工艺系统中压缩气体的目的：
The major reason for compressing gas is to deliver that gas at a pressure higher than that originally existing. The original pressure level may vary from a few inches of water pressure to many thousands of pounds. The pressure rise across a compressor may also vary from almost non-
detectable to thousands of pounds. Gas compression purposes within a chemical process system includes the following:
压缩气体的主要原因是用高于原有值的压力输送那一气体。

原有压力从数英寸水压至数千磅不等。

压缩机前后的压差也从几乎无法检测至数千磅不等。

化学工艺系统内气体压缩的目的包括以下数个：
∙Compressing air for use in instrument air or plant air systems.
压缩空气，以用于仪表用风或厂用风系统。

∙Providing air for combustion in processes such as a furnace or fired heater.
为工艺中燃烧供应空气，例如燃烧或火焰加热器。

∙Circulating process gases for the purpose of reaction, such as a recycle compressor.
循环用于反应的工艺气体，例如循环压缩机。

∙Circulating propane or ethylene gases for the purpose of refrigeration.
循环用于制冷的丙烷或乙烯气体。

mon Types of Compressors and Their Operation
常用类别的压缩机及其运转：
Again, a compressor is simply a gas pump. As with liquid pumps, compressors are classified as either centrifugal or positive displacement. Compressors are used to decrease the volume occupied by a given weight of gas, and thus increase the pressure of air, gas or some gaseous mixture. We will confine our study of compressors to:
同样，压缩机只是一气体泵。

与液体泵一样，压缩机被分类为离心式的和容积式的，压缩机用于减少规定重量气体占用的体积，和由此提高空气、气体或某些气态混合物的压力。

我们对压缩机的研究限于：
∙Centrifugal and axial flow compressors,
离心和轴流压缩机；
∙Positive displacement compressors, including
容积式压缩机，包括：
⇒Reciprocating compressors, and
往复式压缩机，和
⇒Rotary compressors.
旋转压缩机。

Usually, centrifugal and axial flow compressors are driven by turbines or motors at high speed. Since reciprocating and rotary compressors are better suited for lower speed operation, they are usually driven by low-speed, electric motors, gas engines, or steam engines. Small, reciprocating compressors may be operated at speeds up to 1,000 rpm, but most of the machines run between 125 and 400 rpm. Inertia forces limit the speed of large piston compressors.
通常，轮机或电动机高速驱动离心和轴流压缩机。

由于往复和旋转压缩机更适合于低速运转，它们通常由低速电动机，燃气发动机，或汽轮机驱动。

小型往复式压缩机可以以不超过1000转/分钟的速度运转，但绝大数机器以125至400转/分钟的速度运转。

惯性限制了大型活塞压缩机的速度。

III. CENTRIFUGAL AND AXIAL FLOW COMPRESSORS
离心和轴流压缩机：
A. Centrifugal Compressors
离心压缩机：
1) Uses
用途：
Centrifugal compressors (Figure 1) are used where large quantities of air or gas must be handled at comparatively low pressures. They are compact, simple to operate, and need little maintenance. The principle of operation of these compressors is very similar to that of centrifugal pumps. The action is the same for both pumps and compressors, with the
exception that the gas volume is reduced as it passes through the compressor, whereas the liquid volume remains practically constant as it passes through the pump.
在必需处理大量压力相对较低的空气或气体的地方，使用离心压缩机（请参阅图1）。

它们是紧凑型的，操作简单，仅需极少的维护。

这些压缩机的运转原理与离心泵的原理极相似，泵和压缩机的运行相同，例外情况是在气体通过压缩机时其体积减少，而液体在通过泵时其体积实际上保持不变。

（1）导向叶片；（2）叶轮 Figure 1: Multi-Stage Horizontal Centrifugal Compressor
(1)
(2)
图1：多级卧式离心压缩机
2)Major Components and Operation
主要零部件和运转：
The gas enters the impeller near the shaft. Energy is imparted to it by the vanes. As the gas leaves the impeller at a relatively high velocity, it is collected in a volute or series of diffusing passages, which transform the energy into pressure. This conversion is accompanied by a decrease in velocity. After the conversion is accomplished, the gas is discharged to the inlet of the next impeller or from the machine.
气体在轴附近进入叶轮。

叶片将能量传递给它。

在气体以相对较高的速度离开叶轮时，它集中在蜗壳或一系列的导流通道中，将能量转变成压力。

这一转变伴有速度降低。

在转换完成时，气体排入下一叶轮入口或排出机器。

B.Axial Flow Compressors
轴流压缩机：
1)Uses
用途：
Axial flow compressors (Figure 2) are used for low pressure and high capacity service.
轴流式压缩机（请参阅图2）用于低压和高容量应用。

图2：轴流压缩机
（1）排出口；（2）定子导叶；（3）吸入口；（4）转子叶片；（5）外壳；（6）转子叶片； （7）定子叶片；（8）轴；（9）外壳
2) Design and Operation 设计和运转：
Axial flow compressors operate very much like an aircraft propeller or a ventilating fan. Instead of one propeller or one set of fan blades, several sets are mounted in line on a single shaft. The gas passes from one set of moving blades through a set of stationary reversing blades, and on to another set of moving blades. As it passes each set, pressure is increased.
轴流压缩机的运转与飞机螺旋浆或通风机的运转极其相似。

这里若干组叶片在一根轴上安装在一排，而不是一只螺旋浆或一组风机叶片。

气体从一组动叶片通过一组固定逆向导叶，和继续前往另一组动叶片。

随着它通过每组叶片，压力升高。

C. Centrifugal Compressor Sealing/Lubrication and Components
离心压缩机密封/润滑和零部件：
As a Technician, you must have a thorough understanding of different sealing and lubricating systems associated with centrifugal compressor operations. Besides vibration, the common problems in centrifugal compressors involve shaft seal and lubrication systems.
作为技术人员，您必须彻底理解与离心压缩机运转关连的不同密封和润滑系统。

除了振动以外，离心压缩机的常见问题涉及轴封和润滑系统。

In this segment, we'll review the design and operating principles related to: 在本段，我们将审阅与以下零部件有关的设计和运转原理：
Figure 2: Axial Compressor (3)
(6)
(7)
(8)
(9)
(1)
(5)
(4)
∙Non-contact shaft seals
非接触轴封；
∙Contact shaft seals
接触轴封；
∙Bearings
轴承；
∙Lube-oil systems
润滑油系统。

1)Non-contact Shaft Seals
非接触轴封：
Each compressor stage consists of a rotating impeller and a stationary diaphragm. As the gas flows from the eye of the impeller through the diaphragm, its pressure increases. Seals are used between the shaft and the diaphragm to prevent leakage of the gas back from the
high-pressure discharge to the previous stage.
每个压缩机级均包括旋转叶轮和固定隔板。

在气体从叶轮流过隔板时，其压力升高。

在轴和隔板之间使用密封件，防止气体从高压排出口泄漏回前一级。

a) Labyrinth Seal
迷宫式密封：
The most common type of
compressor seal is the labyrinth seal
(Figure 3). The labyrinth seal is a
set of metal rings encircling the shaft
but not touching it. The rings or
teeth are made of soft metal so that
the shaft will not be damaged in case
of accidental contact with the seal.
The rings or teeth are also sharp so
that any friction generated by contact
would be small.
最常用的压缩机密封类别是迷宫式密
封（请参阅图3）。

迷宫式密封是一组
环绕轴的金属环，但不接触轴。

该环
或齿用软金属制成，从而轴在与密封
件意外接触时将不会损坏，环或齿也是锐利的，从而接触产生的任何摩擦均较小。

Figure 3: Labyrinth Seal
图3：迷宫式密封
（1）可以增加排放或惰性气体密封的孔口；（2）内部气体压力；（3）大气
(1)
(2)(3)
The spaces between the labyrinth
teeth form a labyrinthine passage. As the gas enters the space between the teeth (Figure 4), it slows down and changes direction. The resulting turbulence resists the flow of gas. This type of seal is not absolute and does not prevent all leakage. Labyrinth seals are widely used
as interstage seals because the
pressure difference between
stages is normally small enough
for the seal to be effective.
迷宫齿之间的空间形成迷宫式通
道。

在气体进入齿之间的空间（请参阅图4）时，它减速和改变方向，产生的紊流阻止气体流动。

该类密封不是绝对的，不能阻止所有的泄漏。

由于级间压差通常较小，足以有效地密封，所以迷宫式密封广泛用于级间密封。

Gas from a compressor can also leak through the seal to the shaft and then to the casing if the compressor's gas pressure is greater than that of the outside or ambient atmosphere. When properly used, however, seals not only reduce leakage between the shaft and the diaphragm, but between the shaft and casing as well (Figure 5).
如果压缩机气体压力大于外界或环境大气压力，气体也可以从压缩机通过密封泄漏出机壳。

但是，在正确使用时，密封不仅减少轴和隔板之间的泄漏，而且减少轴和外壳之间的泄漏（请参阅图5）。

Figure 4 图4 （1）密封；（2）轴；（3）气体
Figure 5 图5
（1）压缩机压力；（2）迷宫式密封；（3）外部空气压力；（4）外壳
(3)
(1)
(2)
(4)
(1) (2) (3)
b) Ported Labyrinth Seal
带排出孔的迷宫式密封：
If the process gas of the compressor is hazardous or toxic, it cannot be allowed to leak into the atmosphere. When using a labyrinth seal with dangerous gas, the gas must be ported (Figure 6). The port is placed on the seal between the process gas and the atmosphere. Since the pressure in the port area is designed for lower than atmospheric pressure, the process gas will leak to the port. From the port, the gas can then be piped to some safe location.
如果压缩器处理的气体是危险的或有毒的，就不能允许它泄漏进大气。

在使迷宫式密封用与危险气体时，必须用孔口引出气体（请参阅图6）。

该孔口位于工艺气体和大气之间的密封件。

由于孔口区域压力被设计为低于大气压力，所以工艺气体将泄漏入该孔口。

然后可以从该孔口通过管道将气体引向某安全位置。

Figure 7 shows a seal that has been ported so that an inert gas can be forced into the labyrinth of the seal.
If the pressure of the inert gas (usually nitrogen) is higher than the compressor's seal pressure, gas cannot leak to the atmosphere. Because this type of seal does not prevent all leakage, some of the inert gas leaks to the atmosphere, so the labyrinth seal should be used only where leakage of the inert gas is safe.
图7介绍了已装有排出孔的密封，从而可以将惰性气体送入密封的迷宫部分。

如果惰性气体（通常是氮气）压力高于压缩机的密封压力，气体就不能泄漏进大气。

由于该类密封不能阻止所有的泄漏，部分惰性气体将泄漏进大气，因此该迷宫式密封只能用于惰性气体泄漏是安全的区域。

Figure 6
图6
（1）压缩机压力；（2）孔口；
（3）大气压；（4）迷宫式密封
Figure 7: Ported Seal
(1)
(3)
(4)
(2)
c) Restrictive Ring Seal
阻流环密封：
Figure 8 shows a restrictive ring shaft seal. The rings are made out of low-friction material such as carbon. The rings can be in one place, reinforced by a steel band or segmented and held together with a garter spring.
图8介绍了阻流环密封，该环利用低摩擦材料，例如碳，制成。

该环可以位于一个位置，利用钢箍加固或分块和利用环状螺旋弹簧固定在一起。

Figure 9 shows that the rings are held in position around the shaft by stationary ring cups. The ring cups do not contact the shaft. The leakage over the ring is prevented by the vertical contact between the ring and the ring cup. In this type of
seal, the rings actually do not contact the
shaft so that some leakage will occur.
The restrictive ring seal can be ported for
scavenging or inert-gas sealing. The ring seal is also used in conjunction with labyrinth- type seals to further reduce leakage.
图9介绍了利用固定环固定在轴周围位置的密封环。

固定环不与轴接触。

利用环和环形杯之间的垂直接触阻止通过环的泄漏。

在该密封中，碳环实际上不与轴接触，从而将发生某些泄漏。

阻流环密封可以配备用于排出或接入惰性气体密封的孔口。

该环状密封还与迷宫式密封连用，以进一步减少泄漏。

Figure 8: Restrictive Ring Seal 图8：阻流环密封 （1） 可以为密封件增加孔口； （2） 内部气体压力； （3） 可以为应用真空增加排出孔；
（4） 大气
Figure 9: Stationary Ring Cups
图9：固定环
（1）环形杯；（2）环状螺旋弹簧；（3）碳环
(1)
(3)
(4)
(2)
(1)
(2) (3)
2) Contact Shaft Seals 接触轴封：
In a contact seal, leakage is prevented by the contact between a rotating and a stationary port. Such rubbing produces friction, and friction generates heat. Therefore, most types of contact seals must be lubricated to reduce friction and to carry heat away from the metal.
在接触式密封中，利用动环和静环之间的接触阻止泄漏。

此类接触产生摩擦，而摩擦生热。

因此，绝大多数类别的接触密封必须润滑，以减少摩擦和将热量带离金属。

a) Mechanical Contact Shaft Seal
机械接触轴封：
For pressures up to about 1,000 psi, the mechanical contact shaft seal is effective (Figure 10). The seal has a rotating and a stationary seat separated by a carbon ring. The sealing is
accomplished by vertical contact between the carbon ring and the stationary and rotating seat. 在压力不超过约1,000psi 时，机械接触轴封有效（请参阅图10）。

该密封有利用一碳环隔开的动环和静环。

利用静环和动环之间的垂直接触实现密封。

This type of seal requires lubrication.
To lubricate the seal faces, seal oil at
about 40 psi higher pressure than the gas pressure in the seal zone is fed
through a passage drilled in the seal
housing. Besides reducing friction and carrying away heat, the oil itself helps to seal the shaft against
leakage. A labyrinth seal is usually
present between the gas passage and
the contact seal. To prevent the oil from mixing with the gas in the
compressor, a gas flow must exist
down the labyrinth toward the seal.
The oil that is used in the seal does
come in contact with the gas and will
absorb some gas or become
contaminated. It should, therefore, be allowed to drain into a trap where it
can be salvaged. At the atmospheric end of the seal, a pressure-breakdown sleeve is used. 该类密封必需润滑，润滑密封面时，将压力高于密封区域气体压力约40psi 的密封油通过进气口送入密封壳，除了减
小摩擦和携带热量外，密封油本身有助于防止轴泄漏。

气体通道和接触密封之间通常存在一迷宫式密封。

为了防止密封油与压缩机内的气体混合，必须有一气体从迷宫式密封流向该密封。

用于密封的润滑油与气体接触和吸收部分气体后被污染。

因此，应允许将其排入一集油器，在那里处置它。

在密封的大气端使用压力击穿套管。

Figure 10: Mechanical Contact Shaft Seal 图10：机械接触轴封 （1）固定座；（2）运转表面；（3）内部气体压力；（4）清洁密封油入口；（5）压力击穿套管； （6）动环；（7）碳环；（8）密封油出口； （9）大气；（10）污染的密封油出口 (4) (5) (6)
(7) (1) (2) (3) (10) (9) (8)
b) Liquid-Film Shaft Seal
液膜轴封
For sealing pressures of greater than 1,000 psi, a liquid-film shaft seal is used (Figure 11). This type of seal has inner and outer sleeves or rings. The sleeves do not touch each other nor the shaft during normal operation. The shaft itself is also surrounded by a sleeve, and as the shaft rotates, the shaft sleeve rotates with it. If gas leaks from the compressor, it leaks between the shaft sleeve and the seals. High-pressure seal oil is forced between the
sleeves. As the shaft sleeve rotates, it is surrounded by a film of oil. Therefore, the shaft sleeve and the inner and outer sleeves of the seal do not touch.
在密封压力大于1,000psi 时，使用液膜轴封（请参阅图11）。

这一类的密封装有内外环。

正常运转期间，轴套不相互接触，也不与轴接触。

轴本身也被一轴套包围，在轴旋转时，该轴套管随之旋转。

如果气体从压缩机漏出，它就是从轴套管和密封件之间泄漏的。

高压密封油被强制送入轴套和套管之间。

在轴套管旋转时，它被油膜包围。

因此，轴套管和密封件的内外环不接触。

For the oil to seal the shaft sleeve against leakage, the pressure of the oil must be slightly higher than the pressure of the gas. The pressure in the compressor may vary, so the seal-oil pressure must also vary accordingly.
在利用密封油防止轴套管泄漏时，油压必须略高于气体压力。

压缩机内压力可能变化，因此密封油压力也必须相应地变化。

Figure 11: Liquid Film Shaft Seal
图11：液膜轴封
（1） 清洁密封油入口；（2）内环；（3）外环；（4）轴套；
（5）内部气体压力；（6）污染的密封油出口；（7）密封油出口；（8）大气
(1)
(3)
(2)
(4)
(5)
(6)
(7)
(8)
c) Overhead Seal Tank
高位密封油箱：
An overhead tank is used (Figure 12) with the seal for
controlling the pressure of the oil. The top of the head tank is vented to the pressure side of the seal. As this pressure changes, the pressure above the oil changes. Because the oil in the tank has its own static head, it will have its own pressure. A head to 15 to 21 feet of oil will exert from 5 to 7 psi pressure. The pressure of the oil in the seal will be the gas pressure plus the pressure of the oil produced by its head. No matter how much the pressure in the compressor changes, the pressure of the oil will always be more by the amount of head.
高位油箱与密封件连用（请参阅图
12），以控制密封油压力。

高位油箱顶部与密封的压力侧相通。

在该压力变化时，油上方的压力变化。

由于箱中油有其自己的静压头，所以它将有其自己的压力。

15至21英尺油的压头将产生5至7psi 压力。

密封件中油压是气体压力与油压头产生油压的和，无论压缩机中压力变化多少，油压永远较高出气压。

In a liquid-film shaft seal, there is no direct contact between stationary and moving parts. Consequently, there is very little friction and almost no wear of the inner sleeve (Figure 13). As the oil circulates, several gallons per day leak into the pressure side of the compressor. Here, a slinger ring removes the oil.
在液膜密封中，动静环没有直接接触，因而有非常少的摩擦和磨损。

在油循环时，每天有几加仑的油泄漏到压缩机的高压侧，这里有一个油环将油排出。

Liquid-film seals provide a perfect seal against leakage. The seals
do require a continuous supply of clean oil at high pressure. They
also require a seal-oil system for circulating the oil and for maintaining oil pressure. The seal-oil must be perfectly clean. Care must be taken to see that no dirt enters the seal-oil reservoir. Seal-oil lines must also be kept free of foreign particles.
Figure 12 图12
（1）液位控制器；（2）压头油箱；
（3）密封油供应
Figure 13: 图13: （1）密封油；（2）挡油环；（3）轴承
(3)
(2)
（1）
(2)
(1)
(3)
液膜密封提供完全的防泄漏密封，该密封件的确必需连续的高压清洁密封油供应。

它们还需要密封油系统，以循环油和保持油压。

密封油必需是完全清洁的。

必须采取措施保证无污物进入密封油箱，密封油管线也必须保持无异物颗粒。

The oil that leaks into the machine must be removed. The oil is conducted through lines to traps. A trap must be provided for each seal. The oil that goes into the traps is always contaminated with the process gas. Excessive oil flow to the traps indicates that the seal is defective.
漏入机器的油必须清除。

该油通过管线集中在集油器中。

必须为每个密封提供一集油器，进入集油器的密封油总是被工艺气体污染。

进入集油器的密封油流量过大表示密封件损坏。

Both mechanical contact and liquid-film seals use oil under pressure. If the excess oil leaks to the atmosphere, the pressure cannot be maintained. There must be some kind of
restriction to control the amount of oil leaking to the atmosphere. This restriction is usually a sleeve around the shaft called the breakdown or outer bushing sleeve. The oil that flows down this sleeve carries heat away from the seal. This oil flow varies within the seal according to suction pressure.
机械接触和液膜密封均使用压力密封油。

如果过多的密封油漏入大气，就不能保持其压力，必须有某些类别的阻流设备控制漏入大气的密封油量。

该阻流设备通常是轴周围的轴套管，它被称油挡。

流经该轴套管的密封油将热量带离密封件。

在密封件内，这一油流量随着吸入压力变化。

3) Bearings 轴承
Compressor parts are built with very close clearances. The impellers and shaft must be free to rotate, but they must not move any other way. Damage and leakage could result from erratic motion of the impeller or the shaft.
压缩机零件安装成有极小的间隙。

叶轮和轴必须旋转自如，但它们不得以其他任何方式运动。

叶轮或轴的错误运动可能导致损坏和泄漏。

Bearings are used for supporting the shaft with a minimum of friction. They permit the shaft
to rotate freely, but they prevent excessive axial or radial motion. An unsupported shaft can move any of three ways (Figure 14).
轴承用于以极小的摩擦支持轴，它们使轴可以旋转，但防止过大的轴向或径向运动。

无支持的轴可以以三种方式中的任一种运动（请参阅图14）。

Movement along the basis of the shaft is axial motion or thrust. There are forces in the compressor that tend to cause axial or radial motion. For example, gas pushing against the sides of the impellers tends to cause end-to-end or axial motion or thrust. An unbalanced impeller can cause up-and-down vibration or radial motion.
Figure 14: 图14
（1） 旋转（转动）；（2）轴向运动（推力）；
（3）径向运动
(1)
(2)
(3)。