2000 Hook-up Book

Compressed Air Systems

Drainer Installation Automatic drainers are needed at any absorption or refrigerant dryer, and any separator which is instaled in the air line from the aftercooler, or at the entry to a building. They are also needed at the low points in the distribution lines. (Fig. 64) Unless fitted close to the points being drained, and on light loads, drainers often need a bal ance line to allow air to be displaced from the piping or the drainer body as water runs in. The balance line is connected above the drain point, and should not be upstream of it. See Fig. II 115 (page 140).

Distribution Lines These form the all important link between the compressor and the points of usage. If they are under sized, the desired air flow will be accompanied by a high pressure drop. This necessitates extra power input at the compressor. For example, a pressure at the compressor of 120 psi where a pressure of 100 psi would have sufficed without a high pressure drop in the lines, needs an addi tional power input of 10%. The correct size of com pressed air lines can be selected by using Fig. 66 on page 66. Example: 1,000 cu. ft. of free air per minute is to be transmitted at 100 PSIG pressure through a 4” line standard weight pipe. What will be the pressure drop due to friction?

1. Enter the chart at the top at the point representing 100 psig pressure. 2. Proceed vertically downward to the intersection with hori zontal line representing 1,000 CFM. 3. Next proceed parallel to the diagonal guide lines to the right (or left) to the intersec tion with the horizontal line representing a 4" line. 4. Proceed vertically downward to the pressure loss scale at the bottom of the chart. You will note that the pressure loss would be 0.225 psi per 100 ft. of pipe. It is usual to size compressed air lines on velocity, while keeping a watchful eye on pressure drop.

SYSTEM DESIGN

Figure 64 Compressed Air System

Spray Gun

Air Operated Hoist

Instrumentation and Control System

Compressor Cooling Water Control

Drain Trap

Pneumatic Tool

Breathing Mask

Line Separator

Water Cooled Aftercooler

Drain Trap

Machine Tool Air Bearing

Drain Trap

Air Gauging

Receiver

Drain Trap

Drain Trap

Liquid Drain Trap

Pressure Gauge

Drain Traps

Safety Valve

Separator

Strainer

63