Ingersoll-Rand TS8 Owner's Manual page 12

STARTING UNLOADING SYSTEM
The starting unloading feature exists on certain models. The purpose
of the system is to relieve cylinder pressure when the unit stops,
permitting it to start against a light load. A light load increases the life
of the driver and belts and also reduces the possibility of tripping the
overload relay. The system operates in the following manner:
The centrifugal unloader is attached to the end of the crankshaft as
shown in the following illustrations.
When the unit starts, centrifugal force acts upon the unloader
weights and they swing outward. This permits the plunger and
thrust pin to move inward and the pilot valve to close. The escape
path to atmosphere for the cylinder pressure is now closed and the
compressor pumps air in a normal manner.
When the unit stops, the weights retract, permitting the thrust pin
spring to move the plunger and thrust pin outward. The thrust pin
opens the pilot valve and the trapped air pressure escapes from the
cylinder and intercooler through a passage in the frame end cover,
through the unloader tube and to atmosphere through the inlet filter/
silencer.
Position of weight and thrust pin when unit is operating.
Position of weight and thrust pin when unit is stopped.
PILOT VALVE ADJUSTMENT
If the pilot valve tube line is excessively hot, it is a good indication that
the pilot valve is leaking and adjustment is required.
To adjust the pilot valve, proceed as follows:
1. Stop the unit and disconnect and tag the electrical supply main
switch to prevent accidental start-up.
2. Remove the pilot valve tube and the tube fittings.
3. Remove the pilot valve body and all existing shims.
4. Screw the pilot valve body back into the frame end cover (without
any shims) until contact with the thrust pin is felt. Advance the
pilot valve body 1/4 to 1/2 turn more.
EN-12
RELEASED 03/Aug/2021 20:37:49 GMT
If contact with the thrust pin cannot be felt, the following steps may
be necessary to locate the contact point:
1. Insert a small instrument (punch, rod, nail, etc.) into the end of the
pilot valve until it contacts the valve stem.
2. While still inserted in the pilot valve, make a mark on the
instrument even with the outside edge of the pilot valve body.
3. Keeping the instrument pressed lightly against the valve stem,
screw the pilot valve body into the frame end cover. When the
mark on the instrument starts moving out away from the edge of
the pilot valve body, contact has been made with the thrust pin.
4. Advance the pilot valve body 1/4 to 1/2 turn more and proceed
with step five.
5. Measure the gap between the pilot valve body and the frame end
cover.
6. Remove the pilot valve body and add enough shims to fill the gap
measured in step five.
7. Screw the pilot valve body back into the frame end cover until the
body is tight on the shims.
8. Reconnect the pilot valve tube and tube fittings.
Cylinder Relief Valve:
The cylinder relief valve, located in the cylinder(s), acts as a check
valve to prevent air from surging in and out of the pilot valve tube
line; thereby maintaining a high volumetric efficiency. This valve is not
adjustable. If it leaks and a thorough cleaning does not correct the
problem, replace the internal valve parts.
BREATHER/UNLOADER BY-PASS
The breather/unloader by-pass tube lines eliminates air pressure
build-up in the compressor frame by providing a passage for the air
to escape through the inlet unloader (if opened) or (if closed) through
the check valve, therefore, by-passing the inlet unloader and escaping
to atmosphere through the inlet filter/silencer.
OIL CONSUMPTION CHECK
A rule of thumb in determining a "passing grade" for oil consumption
is to consider consumption at or above 50 horsepower-hours per
ounce to be acceptable.
The formula is as follows:
Horsepower X Hours of Operation
To apply this formula, consider the size of the machine. In the
following example, a 5 horsepower compressor uses 2 ounces of oil
every 20 hours of operation.
5 Horsepower X 20 Hours of Operation
The compressor in the example passes the oil consumption test.
New or rebuilt compressor pumps will discharge higher
than normal amounts of oil until the piston rings are seated
(approximately 100 operating hours).
H.P. CYLINDER
BODY SPRING
VALVE
TUBE
NUT
TO PILOT
VALVE
=
Ounces of Oil Used
2 Ounces of Oil Used
NOTICE
CAP
B-9543
Horsepower Hours per
Ounce
50 Horsepower
=
Hours per Ounce
22607402 Rev.J