Air Inlet Sytem, Functional Description - Sullair 4500P User Manual

4500P-7500 USER MANUAL
F L M - 50
ULL OAD ODE
6.9 )
BAR
When the compressed air pressure rises above 50
psig (3.4 bar), the minimum pressure valve opens
allowing compressed air to flow into the service line.
From this point on, the WS Controller continuously
monitors the line air pressure. The pressure regulator
and the solenoid valve remain closed in this mode.
As long as the compressor is running at 100 psig (6.9
bar or lower), the inlet valve is fully open.
M M - 100
ODULATING ODE
7.6 )
BAR
If the rated capacity of compressed air is less than
the demand, the service line pressure rises above
100 psig (6.9) bar). The pressure regulator valve
gradually opens, causing the air pressure to close
the inlet control valve at the same rate, reducing the
volume of air entering the compressor until it
matches the demand. The control system operates
continuously in this mode to accommodate variations
in demand output.
The inlet valve has an orifice that directs a small
amount of air to the compressor inlet when the inlet
control valve is under the pressure regulator's
control. The orifice also bleeds off any accumulated
moisture from the control lines.
U M - G
NLOAD ODE REATER THAN
(7.6 )
BAR
When there is no, or only a small demand, the
service line pressure will rise. The WS Controller de-
energizes the solenoid valve when the pressure
exceeds 110 psig (7.6 bar) allowing the receiver tank
air pressure to be supplied directly which closes the
inlet valve. At the same time the solenoid valve
sends a pneumatic signal to the blowdown valve on
the receiver tank. This component exhausts the
system pressure to the atmosphere and lowers the
receiver tank pressure to approximately 14 psig (1.2
bar). A check valve in the air service line prevents air
from back-flowing to the receiver tank.
When the pressure drops to the low setting: (cut-in
pressure) usually 100 psig (6.9 bar) for low pressure
(7 bar) compressors and 125 psig (8.6 bar) for high
pressure (9 bar) compressors, 150 psig (10.3 bar) for
(10 bar) compressors, 175 psig (12.0 bar) for (12
bar) compressors: the WS Controller energizes the
solenoid valve and the blowdown valve closes. The
solenoid valve now prevents line pressure from
reaching the inlet control valve. If the pressure
18
100 (3.4
TO PSIG TO
110 (6.9
TO PSIG TO
110
PSIG
begins to rise, the pressure regulator resumes its
normal function.
L /N L C
OAD O OAD ONTROL
The compressor can be set to operate without
modulation, operating in the load/no load condition.
This mode is used most often with large air system
volume, e.g., with a receiver or flow controller. This
mode is selected using the WS Controller keypad
and setting modulation to "no" from the menu. A
machine rated for 100 psig (7bar) will run in the full
load mode up to 100 psig (7 bar). If the demand is
less than the compressor's rated capacity, the
pressure will rise above 100 psig and the WS
Controller de-energizes the solenoid valve which
causes the compressor to switch to the unload mode.
When the system pressure decreases to 90 psig (6.3
bar), the WS Controller energizes the solenoid valve
and the compressor switches back to the full load
mode. The compressor's WS Controller keeps the
system pressure stabilized within a range of 90 to
100 psig (6.3 to 6.9 bar).
2.6 AIR INLET SYSTEM,
FUNCTIONAL DESCRIPTION
Refer to Figure 2-6. The compressor inlet system
consists of a dry-type air filter, a restriction gauge
and an air inlet valve.
Figure 2-6: Air Inet System
1. Air Inlet Filter
2. Air Inlet Valve
SECTION 2
3. Compressor Unit
4. Restriction Indicator