Air Flow (See Fig. 2.4); Oil System (See Fig. 2.4) - Chicago Pneumatic CPS 185 PD7 Instruction Book

2.4 Air Flow (see Fig. 2.4)

The system comprises:
AF Air filter
AR/OS Air receiver/oil separator
CE Compressor element
UA/UV Unloader assembly with unloader valve
BDV Blow-down valve
MPV Minimum pressure valve
LV Loading Valve
Air drawn through the airfilter (AF) into the compressor element (CE) is compressed. At the element outlet, compressed air and oil
pass into the air receiver/oil separator (AR/OS).
The check valve prevents blow-back of compressed air when the compressor is stopped. In the air receiver/oil separator (AR/OS),
most of the oil is removed from the air/oil mixture: the remaining oil is removed by the separator element.
The oil collects in the receiver and on the bottom of the separator element.
The air leaves the receiver via the minimum pressure valve (MPV) which prevents the receiver pressure from dropping below the
minimum working pressure, even when the air outlet valves are open. This ensures adequate oil injection and prevents oil
consumption.
A temperature switch (TS) and a working pressure gauge (PG) are comprised in the system.
A blow-down valve (BDV) is fitted in the unloader assembly to automatically depressurize the air receiver (AR) when the
compressor is stopped.
2.5

Oil system (see Fig. 2.4)

The system comprises:
AR/OS Air receiver/oil separator
RV/UA Regulation Valve/Unloader Valve
OC Oil cooler
OF Oil filter
The lower part of the air receiver (AR) serves as oil tank.
Air pressure forces the oil from the air receiver/oil separator (AR/OS) through the oil cooler (OC) and oil filter (OF) to the
compressor element (CE).
The compressor element has an oil gallery in the bottom of its casing. The oil for rotor lubrication, cooling and sealing is injected
through holes in the gallery.
Lubrication of the bearings is ensured by oil injected into the bearing housings.
The injected oil, mixed with the compressed air, leaves the compressor element and re-enters the air receiver, where it is
separated from the air as described in section 2.4. The oil that collects in the bottom of the oil separator element is returned to the
system through scavenging line (SL), which is provided with a flow restrictor (FR).
The oil filter by-pass valve opens when the pressure drop over the filter is above normal because of a clogged filter. The oil then
by-passes the filter without being filtered. For this reason, the oil filter must be replaced at regular intervals (see section 4.2).
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