Product Manual

Industrial / Air Master Series Quincy Compressor

50161-105, March 2008 4 3501 Wismann Lane, Quincy Ill. - 62305-3116

SECTION 2SECTION 2

SECTION 2

SYSTEM DYNAMICSSYSTEM DYNAMICS

SYSTEM DYNAMICS

Description & Application

Quincy Compressor QT Series and PLT Series compressors are heavy duty, air

cooled, belt driven compressors. QT Series two stage compressors are splash

lubricated and capable of delivering 175 PSIG of compressed air. The PLT

Series compressors are pressure lubricated and capable of delivering 175 PSIG

of compressed air.

Principles of Compression Cycles

Two Stage Compressors

During the downstroke of the piston of a two stage compressor, air is drawn

through an intake valve in the head of the compressor into the low pressure

cylinder and compressed during the upstroke of the piston.

The compressed air is then released through a discharge valve in the head

of the compressor to an intercooler (usually finned tubing) where the heat

resulting from compression is allowed to dissipate. The cooler compressed air

is then drawn into a second compression cylinder, the high pressure cylinder,

for compression to final pressure.

From there the compressed air is released through a discharge valve to an

air receiver tank or directly to a network of compressed air supply lines. In one

revolution of the crankshaft a compression cycle is completed.

Principles of Lubrication Systems

Splash Lubricated Compressors (QT Series)

With each stroke of the compressor, a dipper attached to the bottom of the

connecting rod , dips into an oil bath at the bottom of the crankcase. This dipper

splashes oil throughout the interior of the crankcase, lubricating all moving

parts.

It is important with this system that the correct oil level be maintained. If

the oil level is too high, excessive oil carryover could result. If the oil level is too

low, or the compressor is not operated within the correct RPM range, the

moving parts will not be adequately lubricated.

Pressure Lubricated Compressors (PLT Series)

Moving parts within the crankcase are supplied with lubrication by a positive

displacement, gerotor type oil pump. Oil is drawn up from the bottom of the

crankcase to the oil pump through an oil sump strainer screen. Oil travels

under pressure through drilled journals in the crankshaft to lubricate crank-

shaft bearings and connecting journals.

Optional Low Oil Level Switch

QT-5, PLT-5, QT-7.5, PLT-7.5 & QT-10 compressors are available with an

optional low oil level switch. A separate instruction manual is available which

explains the operation, retrofit installation, and removal for inspection of the

low oil level switch. Request instruction manual # 112210-101.