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GROOVES
F TO C OF FLYWHEEL L
| D |
C OF COMPRESSOR |
|
L | C |
| |
| A |
Fig. 17 — Flywheel
Table 21 — Flywheel Data
FLYWHEEL | FLYWHEEL | WIDTH | OD | PITCH | GROOVES | |
PACKAGE | DIAM | (No. and | ||||
MODEL | A (in.)* | C (in.)* | ||||
NUMBER | D (in.)* | Type) | ||||
13/4 | 8.0 | 7.5 | ||||
21/2 | 8.0 | 7.5 | ||||
21/2 | 10.0 | 9.5 | ||||
31/8 | 10.0 | 9.5 | ||||
33/8 | 11.75 | 11.0 | ||||
53/8 | 11.75 | 11.0 | ||||
63/8 | 11.75 | 11.0 | ||||
93/8 | 11.75 | 11.0 |
*Refer to Fig. 17.
Table 22 — Flywheel — Compressor Dimensions
COMPRESSOR | FLYWHEEL | DIMENSIONS | |
MODEL | MODEL | F (in.)* | |
5F20 | 67/8 | ||
5F30 | 85/8 | ||
83/4 | |||
5F40 | 105/8 | ||
5F60 | 115/ | 8 | |
| |||
| 113/4 | ||
5H40 | 131/4 | ||
1311/ | |||
|
|
| 16 |
5H60 | 14 |
| |
147/16 | |||
| 20 |
| |
5H80 | 207/16 | ||
189/16 | |||
| 215/16 | ||
5H120 | 2011/ | ||
| 16 | ||
| 219/16 |
*Refer to Fig. 17.
BOOSTER COMPRESSORS FOR
REFRIGERANT 12, 22, 502, AND 507/404A
Booster Application Data — The following data sup- plements the
Rating Basis — All booster ratings* are given in refriger- ation effect and are based on:
1.Use of a
2.The liquid refrigerant at Point A (Fig. 18) at satu- ration temperature corresponds to booster discharge pressure. This is often referred to as saturated inter- mediate temperature.
This occurs when booster discharge gas is condensed in a cascade
3.Use of only half of the standard number of suction valve springs per cylinder. All 5F,H compressors are factory assembled with the standard number of suction valve springs; therefore,
4.Booster ratings are based on a 1750 rpm compressor speed.
“R” Factors — In a multistage compression system, the intermediate or
To assist in the selection of higher stage compressors, Table 23 presents “R” factors that depict approximate required relationship between stages at various saturated temperature conditions.
To determine the required capacity of a higher stage com- pressor, multiply lower stage compressor capacity by the proper “R” factor from Table 23. Any additional loads handled at intermediate pressure must be added to this figure to arrive at the total higher stage load.
Multistage System Pointers — A staged system is essentially a combination of 2 or more simple refrigerant cycles. In combining 2 or more simple flow cycles to form a staged system for low temperature refrigeration, 2 basic types of combinations are common (Fig. 18).
DIRECT STAGING — Involves use of compressors, in series, compressing a single refrigerant.
CASCADE STAGING — Usually employs 2 or more refrig- erants of progressively lower boiling points. Compressed refrigerant of low stage is condensed in an exchanger (cascade condenser) that is cooled by evaporation of another lower pressured refrigerant in the next higher stage.
Safety Factors — Use of capacity safety factors in select- ing booster compressors must be a matter of judgment when making selection.
Factors that have a bearing on satisfactory compressor selections are: accuracy of load estimate, amount of safety factor included in the total load, degree of importance of meet- ing specified capacity at given condition, temperature level of operation and magnitude of refrigeration load. All of the factors must be recognized when considering the use of a capacity safety factor in selecting a booster compressor.
Figure 19 presents reasonable safety factors for use in selec- tion of booster compressors. These can be employed when it is not desired to establish a factor based on selector’s judgment.
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