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Then, overcoming spring 7 force of the check valve 8, compressed air is fed to outlet III
and then to the truck brake system. Simultaneously, compressed air having overcome spring 6
force of the throttle valve 5 having 1.5 mm diameter hole, enters the regeneration air tank through
outlet II. At the same time compressed air goes through Д cavity under the balancing piston 13
impacted by spring 11. Herein, discharge valve 14 connecting E cavity over the unload piston 17
with the environment through Ж channel and З cavity, is open. Discharge valve 24 is closed under
impact of the tappet 25 and spring 12. Also unload valve 18 is closed under the impact of spring
19. Such condition of water and oil separator with installed pressure controller corresponds to
compressed air level in the brake system receivers coming from the compressor.
When switch-off pressure in Д cavity is achieved, the balancing piston 13 having over-
come spring 11 force, moves right. Herein, discharge valve 14 closes and discharge valve 24
opens. Compressed air from Д cavity enters E cavity through open discharge valve 24, unload pis-
ton 17 moves downwards, unload valve 18 opens and compressed air from the compressor is dis-
charged to the atmosphere together with collected condensed water over unload valve seat and
discharge valve 18. Herein, pressure in Г channel and B cavity falls, the check valve 8 closes. As
a result the compressor works in unloaded mode without back pressure.
At the same time the throttle valve 5 closes. Dry air is discharged to the environment
from the regeneration air tank through 1.5 mm diameter throttle hole of the throttle valve 5, chan-
nel Г, B cavity and the adsorption case, restoring zeolite 2 properties, grasping water, oil drops
and dust particles sedimentated in filter 1.
When pressure on III outlet drops (due to air consumption) to the pressure of switch-on,
balancing piston 13 moves left by spring 11 force. Discharge valve 24 closes, discharge valve 14
opens and connects E cavity with the environment through Ж channel and З cavity. Herein, un-
load valve 18 by spring19 force closes and the compressor pumps compressed air to the system
receivers again.
Besides, unload valve 18 works as safety valve. If the installed pressure controller is not
actuated when switch-off pressure is achieved, then reaching switch-on pressure of the safety
valve actuation, unload valve 18 opens overcoming spring 19 and 14 force, and air is discharged
to the environment. Actuation pressure of the safety valve is adjusted by number of washers 20,21
under the unload valve spring 19. Installed heater 22 of the unload unit prevents failures due to
possible freezing of condensed water.
Structural feature of this water and oil separator is that unload valve is located in the di-
rect flow of heated compressed air fed from the compressor. In case of heater electrical circuit
failures, sometime later warm air coming from the compressor will heat the unload valve, the lat-
ter will return to its normal position and the pressure controller will switch on to fill the system. In
case of heavy clogging or moisture freezing in the adsorption case due to improper operation
(long operation without regeneration, etc.) causing air flowing through the adsorption case, air
feeding to the pneumatic system is done through the air-escape valve 3 with pressure difference of
0.15-0.24 MPa, the latter can be adjusted with the washer 26 under the unload valve spring 4.
Herein, the device only adjusts pressure. This operation mode of the device is emergency mode, it
is allowed only when it is not possible to replace the case in field or restore its flow, but it is nec-
essary to drive farther. Long operation in the emergency mode especially in low temperatures can
lead to pneumatic system devices failure due to negative impact of the condensed water.
Summary of Contents for 4320M
Page 1: ...URAL 4320М TRUCK and its Modifications ...
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Page 177: ...Figure 140 Installation of left and right side safety devices 171 ...
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