13–10–612 Page 23
Discharge
Compressor
Manifold
Delivery
Inlet Valve
Turn Valve
Pressure
Full Capacity
Open
Closed
100
70% Capacity
Open
50% Open
100
40% Capacity
Open
Full Open
100
30% Capacity
Closing
Full Open
103
20% Capacity
Closing
Full Open
103
0% Capacity
Closed
Full Open
103
AIR CONTROL COMPONENTS – Refer to
FIGURE 4–1, page 20, FIGURE 4–8, FIGURE 4–9,
and FIGURE 4–10, pages 30 through 32, for schemat-
ic tubing diagrams.
Inlet Valve (FIGURE 4–2, page 21) – The inlet valve
restricts the inlet to control capacity and closes to un-
load the compressor. At shutdown, the inlet valve
closes to prevent backflow of air.
The inlet valve position is controlled by air pressure in
its piston cylinder, which is controlled by the program-
mable controller through solenoid valves IVC and IVO.
As pressure to the piston is increased, the valve closes
to restrict air flow and compressor delivery. See
FIGURE
4–8, FIGURE 4–9, and FIGURE 4–10,
pages 30 through 32.
Purge Air Valve – The purge valve is a normally
closed two–way air actuated valve that admits purge air
from the final discharge manifold to the compressor to
counteract the oil knock that occurs in oil–flooded
rotary screw compressors when they are completely
unloaded with pressure in the oil reservoir. This valve
is controlled by the same control pressure which con-
trols the inlet valve.
Solenoid Valves IVC and IVO – These valves control
position of the inlet valve in response to signals from
the ”Auto Sentry–ES”. With both valves de–energized,
the normally open IVC valve allows control pressure to
the inlet valve piston to close the valve. If IVC only is
energized, the inlet valve is held in its current position.
If both valves are energized, control pressure is re-
lieved from the inlet valve piston to allow the valve to
open.
Pressure Regulator – The pressure regulator is used
to supply a constant and low control pressure to pre-
vent damage to the inlet valve from ”slamming.” The
regulator should be set for 25–30 psig.
Shuttle Valve – (FIGURE 4–4) Also known as a
double check valve, the shuttle valve is a device which
will take two (2) supply signals and allow the one with
the highest pressure to pass through. The shuttle valve
is used to provide control air pressure from either the
FIGURE 4–4 – SHUTTLE VALVE
reservoir or plant air system, as required during differ-
ent operating conditions.
Blowdown Valve – (FIGURE 4–3) The blowdown
valve is a two–way solenoid valve which is piped into
the oil reservoir outlet but ahead of the check valve.
When the solenoid is de–energized, the valve opens
and the oil system is blown down. When the solenoid
is energized, the valve closes to allow the oil system to
pressurize. A control air check valve is provided to en-
sure that the inlet valve closes during blowdown.
Solenoid Valves TVC and TVO – These valves con-
trol position of the turn valve in response to signals from
the ”Auto Sentry–ES”. With both valves de–energized,
equal pressure is supplied to both sides of the actuator
to hold it in its present position. If TVC only is energized,
the right side of the turn valve actuator is exhausted to
the compressor inlet cavity, causing the turn valve to
move towards the full load position. If TVO only is ener-
gized, the left side of the turn valve actuator is ex-
hausted to the compressor inlet cavity, causing the turn
valve to move towards the unload position. See ”Con-
trol System Operation” in this section for a description
of how the turn valve components respond during op-
eration.
Turn Valve – The turn valve is a helical valve which,
when rotated, opens and closes a series of ports cast
into the compressor cylinder. When these ports are
open, they direct some of the air which would otherwise
be compressed back to the inlet, reducing both capac-
ity and power consumption.
Turn Valve Actuator – (FIGURE 4–5, page 24) The
turn valve actuator is a rotary rack and pinion device
which positions the turn valve according to system de-
mand. Filtered oil from the compressor sump is di-
rected to the outboard end of the two actuating cylin-
Summary of Contents for ELECTRA-SAVER EAU PD - 200 HP
Page 13: ...13 10 612 Page 3 FIGURE 1 4 STARTER BOX FIGURE 1 5 PACKAGE CONTROLLER AND STARTERS...
Page 16: ...13 10 612 Page 6 DECALS 206EAQ077 212EAQ077 218EAQ077 211EAQ077 207EAQ077...
Page 17: ...13 10 612 Page 7 DECALS 216EAQ077 217EAQ077 222EAQ077 221EAQ077 208EAQ077...
Page 40: ...13 10 612 Page 30 FIGURE 4 8 CONTROL SCHEMATIC COMPRESSOR AT FULL LOAD 214ECM797 Ref Drawing...
Page 42: ...13 10 612 Page 32 FIGURE 4 10 WIRING DIAGRAM 212EAP546 Ref Drawing...
Page 43: ...13 10 612 Page 33 FIGURE 4 11 AUTO SENTRY ES CONTROLLER DISPLAY...
Page 45: ...13 10 612 Page 35 FIGURE 5 1 FLOW DIAGRAM AIR OIL SYSTEM 215EAU797 Ref Drawing...
Page 65: ......