压缩机基础术语

10
Terminology
In-Hg = inches of mercury pressure = can be a manometer or mercury filled gauge, used where pressures are low & extreme accuracy is desired = 1” Hg = .491 PSI
8
Terminology
Total Swept Volume Example (DA):
6” Diameter x 11” Stroke 2.5” Piston Rod Diameter Total Swept Volume = (2 X 28.274 - 4.909) X 11 = (56.548 - 4.909) X 11 = 51.639 X 11 = 568.029 cu. In.
= inches of water pressure = usually a manometer filled with water = used for measuring very low pressure = 1/13.6 as heavy as mercury 13.6” of H2O = 1” of Hg = .491 PSI
6
Terminology 术语
Capacity = (or flow rate) Volume of gas compressed and delivered at specified conditions of temperature & pressure measured at the compressor inlet. Usually expressed as volume/unit of time cubic feet per minute or cubic feet per day.
Temperature range: Centigrade = 100° = Fahrenheit = 13 180° =
5 9
Terminology
Temperature Scales:
Converting from ° F to ° C expressed as follows: ° C = 5/9 X (° F - 32)
HP = 21 X 4.2 X 2 X 1 HP = 176.4
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Configuration
V
Configuration
Inline
Horizontal Opposed
Configuration
Separable Engine
20
Terminology
Separable Compressor Frame
(1.26-1/1.26)
T2 = 520 X 2.94
.2
Ps = 500 PSIG Pd = 1500 PSIG K = 1.26
T2 = 520 X 2.94 T2 = 520 X 1.24 T2 = 644.8° R or 184.8° F
16
Terminology
Finding Ratio of Compression (RC) Example 1: Ps = 200 psig, Pd = 600 psig
21
Compressor
Engine
Coupled Separables
22
1L 2L 3L 4L 5L
Left Bank
Approach = （设计）温差 30°F approach means the cooler will cool the gas to 130° when ambient temperature is 100°F
7
Terminology 术语
Swept Volume 工作容积 = The volume swept by the piston during the forward and/or backward stroke. = Compressor speed is not a factor. = Normally expressed in cubic inches and calculated as follows:
HP 21 Rc S Q = Horse Power = Standard (Constant) = Ratio Of Compression = # of Stages = Quantity in MMCFD
HP = 21 x 2.86 x 1 x 2 = 120.12 or 121
18
Terminology
Note: If we had not converted to psia the ratio would have been 30:1.
17
Terminology
Finding Approximate HP Requirement: To find the HP required for a single stage unit (example 1): Approximating HP Formula using Example #1 HP = 21 x Rc x S x Q Where:
天然气压缩机 基础术语
压缩机基础术语
(Jargon)
压缩 = 压迫或压缩进入一个较小空间的动作。
2
压缩机基础术语
R/Rc Ps/P1 Pd/P2 Ts/T1 Td/T2 Ta Hp HE CE VE K = = = = = = = = = = = 压缩比 吸气压力 排气压力 吸气温度 排气温度 环境温度 马力（功率单位） 缸头端 曲柄端 容积效率 特定天然气的比热比
9
Terminology
Units of Measure: PSI PSIG PSIA MMCFD MMSCFD 60°F = pounds per square inch = pounds per square inch gauge = pounds per square inch absolute = gauge + atmospheric pressure = million cubic feet per day = million cubic feet per day @ the standard conditions of 14.65psia &
Example:
Convert 100° F to ° C ° C = 5/9 X (100 - 32) = 5/9 X 68 = 37.8° C
14
Terminology
Temperature Scales: Degrees Rankin (° R) = Absolute temperatureEnglish Units Used mostly in scientific work which relates the Fahrenheit scale to absolute temperature. Calculations are based on zero molecular energy. Zero Molecular Energy = -460° F or absolute zero Converting from ° F to ° R is expressed as follows: ° R = ° F + 460 Example: 100° F + 460 = 560° R
Finding Approximate HP Requirement: To find the HP required for a two stage unit (example 2): Take the square root of the ratio found earlier: Rc = 17.71 = 4.20 HP = 21 x Rc x S x Q
3
Terminology 术语
Ratio of Compression (RC) 压缩比 RC = 排气压力(Pd)psig + 14.7 = ??? psia 吸气压力(Ps)psig + 14.7 = ??? psia
注: 当计算压缩比时，必须要考虑海拔和大气压力。
4
Terminology 术语
DA 双作用
5
Terminology 术语
Clearance Volume= The volume remaining in the 余隙容积 compressor cylinder at the end of the discharge stroke. Normally expressed as a % of piston displacement.
SA 单作用 = Single Acting - The act of compressing on one end of the compressor cylinder. = Double Acting - The act of compressing on both ends of the compressor cylinder.
15
Terminology
Temperature Scales: Degrees Rankin(cont.) One use for ° R: Finding Discharge Temperature (T2)
(K-1/K)
520°R T2 = T1 X Rc
T1 = 60° F + 460 =
Swept Volume HE = Area of Piston X Stroke in Inches Swept Volume CE = (Area of Piston - Area of Rod) X Stroke in Inches Total Swept Volume = (2 X Area of Piston - Area of Rod) X Stroke In Inches
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In-Hale Waihona Puke Baidu2O
Terminology
Temperature Scales:
Temperature = A measure of molecular energy… the higher the temperature the more molecular energy. Degrees Fahrenheit (°F) = Temperature scale where, at sea level, the freezing point of water is 32° & the boiling point is 212°. The distance between these two points is 180°.
Rc = 600 psig + 14.7 = 614.7 psia = 2.863 200 psig + 14.7 = 214.7 psia
Example 2: Ps = 20 psig, Pd = 600 psig
Rc = 600psig + 14.7 = 614.7psia = 17.7 20psig + 14.7 = 34.7psia
Displacement 排量 = Area of piston X length of stroke X # of strokes per minute. For DA compressors, the displacement on the CE is less than the HE due to the rod area. Normally expressed in cubic feet per minute or CFM.
12
Terminology
Temperature Scales: Degrees Centigrade or Celsius (°C) = A scale used worldwide which relates to the metric system. At sea level, the freezing point of pure water is 0° & the boiling point is 100°. The distance between these two points is 100°.