Gardner Denver APEX25-30A Operating And Service Manual Download

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MISCELLANEOUS CONTROL DEVICES

- Refer to

Figure 4- 8, page 52 for the schematic diagram of the control system.

Intake [Air] Filter (1) -

Captures solid impurities in the air stream entering compressor inlet. It also attenuates

noise emitted by the compressor inlet.

Inlet-Valve Assembly (2) -

This device controls the intake of atmospheric air entering the compressor during the

Load/Unload or the optional Inlet Modulation operational phases:

During the loaded state: The

inlet poppet (2.2)

remains open and enables atmospheric air to enter the

compressor inlet - this is done by venting to atmosphere the gas trapped underside of the piston via

check

valve (19)

and

orifice

(18)

During the unloaded state: The

3/2-way solenoid valve (Y

) feeds pressurized air underneath the

piston

(2.1)

, forcing it and

the inlet poppet (2.2)

upward and blocking-off the compressor intake. A small purge

check valve (2.3)

, located in the poppet, allows a stream of air to reach (e.g., purge) the rotors and keep

them from unstable, noisy operation and producing sufficient pressure to maintain cooling / lubricating oil
flow. A small amount of air is dispensed by

orifice (18

) to scavenge shaft seal challenge back into the

compressor inlet. See Section 9, page 70, for maintenance information.

During inlet modulation state: See the segment further down on Inlet Flow Modulation Hardware Option for
details of this sub-system. Note that this option is available only for Fixed Speed package variants.

Electric Motor (3) –

Drives the

compressor (4)

via a

belt drive assembly (5).

It is energized by the wye-delta-

type starter, which in turn is controlled by the ASG2 controller.

Oil Sump (6) –

This pressure vessel separates by inertial effects the bulk of the compressed air and injection oil

streams and serves as a sump for the latter.

Air/oil separator (7) -

Intercepts and coalesces the aerosol oil stream in the compressed air exiting the inertial

separation process within the oil sump.

Oil Filler Cap (8) –

Oil fill port on the oil sump.

Oil drain [valve and plug] (9)

– It is the low drainage point for the oil system. It is located at the bottom of the

sump and includes a flexible hose to route drained oil unto a suitable container.

Oil Level Indicator (10) -

This gauge is located on the oil sump and indicates the oil level. See

“Oil Level Gauge”

on Section 5, Page 53, for more details.

Oil Filter (11) -

Captures solid impurities in the oil entering the compressor injection port.

Oil Cooler (12) –

The air-cooled heat exchanger removes heat from the oil stream prior to injection.

Pressure Relief Valve (13)

– This device protects the pressure containing components of the compressor

package against high pressure exceeding 188.5 psig. Section 9, See page 70, for maintenance information.

Minimum Discharge Pressure/Check Valve (14) -

This device maintains minimum pressure (60psig) within the

air/oil sump, thus ensuring adequate lubricating oil injection flow to the compressor even when no air delivery into
the system is taking place. It also functions as a check valve to prevent reversed air flow from the system line
during compressor stoppage. See Section 9, page 70, for maintenance information.

Air cooler (15) –

The air-cooled heat exchanger removes heat from the air stream prior to exit from the package.

Scavenge line orifice (16) –

This orifice controls the amount of oil and compressed air that is returned from the

air/oil separator back into the compressor.

Thermal Mixing Valve (17) –

This device mixes hot oil from the oil sump and cooled oil from the oil cooler prior to

delivery to the oil filter and ultimate injection. See Section 9, page 70, for maintenance information.