Air System; Description; Theory Of Operation; Maintenance - Manitowoc Grove TMS700E Service And Maintenance Manual

TMS700E SERVICE MANUAL

AIR SYSTEM

Description

The air system (see Figure 8-55) provides the air supply to
operate the service brakes, parking brakes, air suspension
system, inter axle and cross axle differential locks, tire
inflation option, and other air accessories.
The air system is pressurized by an engine-mounted air
compressor and the pressurized air is stored in six air
r e s e r v o i r s u n d e r n e a t h t h e f r a m e . T h e a i r s y s t e m
components are operated by the air that is stored in these
reservoirs.
An air dryer is mounted on the left side of the carrier frame
just behind the front bumper. It is connected between the
outlet of the compressor and the front primary supply
reservoir. Oil, water, and contaminates are removed from the
air during the compression cycle and when the governor is
unloading, the contaminates are removed from the dryer.
The air system is split into a primary system and a secondary
system. The systems are isolated from each other so that in
the event of a failure of one system, air is retained in the
other system. By means of pressure protection valves, check
valves, and spring brake valves, a reserve of air pressure
remains to operate the spring brakes through normal use of
the brake pedal. Any unusual loss of pressure should be
investigated immediately and corrected, so as to restore the
full backup capability of the system.

Theory of Operation

Through reciprocating motion, the piston in the compressor
compresses air with every cycle. The compressed air passes
through the air dryer and onto the primary front supply
reservoir (tank #1). The primary front supply reservoir helps
cool the heated air and contains an automatic drain valve to
vent off condensed water. A 10.30 bar (150 psi) safety valve
is installed on the supply reservoir for protection from excess
pressure. The pressurized air flows to the primary rear
service reservoirs (tanks #4 and #5) and secondary service
reservoirs (tanks #2 and #3) from the primary front supply
reservoir. Both primary and secondary air reservoirs provide
the supply for the dual brake and spring brake control valves.
Air to the service brakes on axles #2, #3, and #4 is supplied
by both primary rear service reservoirs. The secondary
reservoirs provide the supply for the service brakes on axle
#1. The auxiliary air reservoir provides the air supply to
operate all other air components.
The three pressure protection valves are set at 5.90 bar
(85 psi) and are basically check valves. They open at 0.70 to
1.00 bar (10 to 15 psi) above their closing pressure. These
valves protect a circuit if a line is ruptured to ensure a priority
supply to the brakes.
Grove
The compressor, which is mounted on and driven by the
engine, is regulated by an air governor which vents the
compressor when a pressure of 9.30 bar (135 psi) is sensed
in the air system. When pressure drops to 7.90 bar (115 psi),
the governor will allow the compressor to supply the air
system to maintain proper system pressure.
Braking
The top priority of the air system is to provide braking. Each
rear wheel has a spring brake chamber and a service brake
chamber. The spring brake is applied by a spring and
released by pressurized air. The spring brakes on all four
rear wheels are released by the parking brake push-pull
knob on the right hand console in the cab. Pushing in on the
parking brake causes air pressure to enter the spring brake
chamber on each wheel and compress the spring, releasing
the brakes. At least 2.80 bar (40 psi) is required to keep the
parking brake valve engaged. If supply pressure to the valve
drops below 2.80 bar (40 psi), the valve will release, applying
the brakes.
The service brakes are applied by air pressure. Depressing
the foot brake pedal on the cab floor causes pressurized air
to enter the service brake chamber on each wheel and apply
the brakes. In the event of a loss of supply pressure to the
service brakes, the spring brake valve will allow the operator
to release or bleed off the air pressure in the spring brake
chamber by depressing the foot brake pedal to apply the
brakes.

Maintenance

Depressurize both air systems completely before
disconnecting air lines or components.
Do not expose nylon tubing to flames or heat. Replace
tubing if outside covering shows white. Eliminate cause of
chafing or other damage.
Leak Detection
If a leak is suspected, shut off the engine and note the air
pressure reading of both circuits. Acceptable air pressure
loss is 0.40 bar (6 psi) within 30 minutes. A hard to detect
leak can be found by wetting the suspected area with a soap
solution and observing for bubbles.
Published 01-29-2015, Control # 512-01
UNDERCARRIAGE
WARNING
CAUTION
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