MXPA00008341A - Air dryer reservoir module components - Google Patents

Abstract

An air dryer and reservoir assembly for providing compressed air from an air compressor (20) on a heavy motor vehicle which includes an air dryer (14) connected to receive compressed air from the air compressor (20) and a secondary reservoir (12), including an integral purge volume (34), for storing compressed air which passes through the air dryer (14), with the air dryer (14) and the secondary reservoir (12) being securely attached to a housing (16) to form an air dryer reservoir module (10). A primary reservoir (18) for storing compressed air from the air dryer (14) is located remote from the air dryer reservoir module (10). A pressure equalizing mechanism (57) is disposed between the primary reservoir (18) and the secondary reservoir (12) for keeping pressure in the two reservoirs (12, 18) equal. Components located within the housing (16) control air flow between the air dryer (14) and the primary and secondary reservoirs (18, 12) and also monitor the pneumatic brake system circuits fed by the primary and secondary reservoirs (18, 12).

Description

MODULAR DEPOSIT COMPONENTS AIR DRYER Reference to related applications This application is a continuation in part of the application of Copending United States Patent No. 08 / 993,931 Proxy Registration No. 591-96-006) entitled "Air Dryer Deposit Module" filed on 18 December 1997 and assigned to the assignee of the present application. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to air dryers and, more specifically, to an air dryer and a reservoir, including a separate purge volume, constructed together as a module. 2. DESCRIPTION OF THE PRIOR ART Air dryers 20 have been used for many years to dry the air in an air brake system for heavy vehicles. The sales of cleaning and air drying in air brake systems have been recognized for a long time, since moisture trapped in the air brake system can, during operation in cold weather, cause components of A. ^ .. Aiii ^^^ ^^ ^ aai ^^ ^ ** ^ '* < a __ air brake system freeze, making the system inoperable. These prior art air dryers typically include a desiccant material through which the compressed air flows. When the air compressor of the vehicle has loaded the air tanks of the vehicle to a sufficient level of pressure, the compressor is discharged so that it no longer compresses air. When the compressor is discharged, a signal is transmitted to a purge valve that is carried inside the air dryer and that makes the air stored tablet flow against flow through the desiccant at a controlled rate to regenerate the desiccant. The air used to regenerate the desiccant can be compressed air stored in a purge volume integrated into the air dryer or the air dryer. compressed air stored in a separate tank. Most of the prior art compressed air systems for air brake applications in heavy vehicles use three tanks that are separate from the air dryer. A compressor feeds air dryer with compressed air that then flows through the desiccant bed and is fed to a remote feed tank. The supply tank is connected to feed compressed air to a primary tank and a secondary tank. Primary deposits and secondary supply pneumatic circuits that can T ^ M ^ ¡t ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ To protect against the loss of air pressure, each of the primary and secondary tanks includes a check valve in its pneumatic connections to the supply tank. A pneumatic control pipe extends from the feed tank to an air pressure regulator that controls the loading and unloading of the air compressor.

SUMMARY OF THE INVENTION The present invention is for a dryer unit and air receiver, for providing compressed air from an air compressor for operating the brakes of a heavy motor vehicle, including an air dryer connected to receive compressed air from the air compressor, a secondary air reservoir separated from the air dryer, a housing containing pneumatic circuit components to control the flow of compressed air from the air compressor through the air dryer to the secondary reservoir, having the air dryer air attached securely to a section of this and the secondary tank securely attached to the other section of this to secure the air dryer and the secondary tank together as a unit air dryer unit module. The system of compressed air brakes with the module of the ^^ w ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The air dryer reservoir also includes a primary air reservoir having a pneumatic connection to the remote located housing of the secondary air reservoir with the reservoir containing pneumatic circuit components 5 to control the flow of compressed air between the air dryer and the air dryer. primary air reservoir. The pneumatic circuit protection valves are located inside the housing to monitor the pneumatic circuits fed by the primary and secondary reservoirs. As well a means of detecting faults inside the housing is located to detect a failure of the pneumatic circuits that are fed by the primary and secondary reservoirs and in the case of a failure of these pneumatic circuits the speed of the heavy vehicle is limited. The air charge and treatment subsystem in the presently described air brake system known as the air dryer tank module provides a cost-effective and simplified air loading subsystem, using integrated components. The module of the warehouse The air dryer is configured in a form that allows the elimination of the feed tank, which is used in the three-tank, normal system, while providing a means to detect both the primary tank and the secondary tank for the compressor at the same time. air and air dryer control.

The air dryer tank module integrates the components such as pressure protection valves, the air compressor regulator, the pressure relief valves, pressure detectors and the like in a way that eliminates the need for the power tank, the safety valve of the power tank, some of the external pipes of the three normal tank system and many of its accessories. The reduction of components, accessories and pneumatic tubes reduces potential failure modes. With respect to a normal three-tank system, the air dryer tank module integrates the following components: air dryer, primary and secondary check valves, secondary drain and supply valves, safety valve of the feed tank, the compressor regulator, pressure protection valves of the auxiliary system and the supply and secondary tanks. The purge volume can be constructed at the end of the secondary reservoir to which the air dryer is attached. An internal screen separates the secondary reservoir volume from the purge volume. The internal communication ducts connect the secondary reservoir and the purge volume with the air dryer. The dryer tank module can also be constructed to equalize the pressure between the primary tank and the secondary tank, so that if the vehicle is parked for a certain time, the pressure does not have to be charged again. Limiting by this means the use of the vehicle with a deposit with severe leaks. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention reference is made to exemplary preferred embodiments of the inventions shown in the accompanying drawings, in which: Figure 1 is an illustration of the three-component compressed air loading system deposits of the prior art. Figure 2 is an illustration of the compressed air loading system using an air dryer reservoir module in accordance with the present invention; Figure 2A is an illustration of an interior view of a portion of the compressed air loading system utilizing an air dryer reservoir module shown in Figure 2. Figure 3 is a perspective view of a reservoir dryer module. of air according to the invention. Figure 4 is an illustration of an air dryer reservoir module in accordance with the present invention showing some of the internal pneumatic flow paths and control components. 25 Figure 5 is an illustration of a deposit module ^^.-'- ^ l ^ g ^^ H ... ... ~ - _ ^ J__B * --__-._-. air dryer according to the present invention used in a service braking system for a heavy motor vehicle. Figure 6 is a schematic illustration showing the components included in one embodiment of the air dryer reservoir module. Figure 7 is a view of an air dryer reservoir module according to the present invention with a screen separating the reservoir into two chambers; and Figure 8 is an illustration of a pneumatic pressure equalizing circuit for connecting the two reservoirs used with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now with reference to the drawings and Figures 2 and 3 in particular, there is shown an air dryer reservoir module 10 according to the present invention. The air dryer module 10 provides the compressed air received from an air compressor 20 to operate the brakes of a heavy motor vehicle. The air dryer module 10 includes an air dryer 14 connected to receive compressed air from the air compressor 20, a secondary air tank 12 is separated from the air dryer 14, and a housing 16 containing pneumatic circuit components for controlling the air dryer. flow of compressed air from the air compressor .. «gÉMfcU-AÉ» ». * ^. ^. - .. k ^ - ^ lfaS ^^ 20 through the air dryer 14 for the secondary tank 12 and a primary tank 18. The housing 16 has the air dryer 14 securely attached to a section of this and the tank secondary 12 securely attached to the other section thereof to join the air dryer 14 and the secondary tank 12 together forming the unitary air dryer reservoir module 10. The compressed air brake system with the reservoir module Air dryer 10 also includes an air tank primary 18 having a pneumatic connection 22 to the housing 16 located away from the secondary air reservoir 12. the housing 16 also contains pneumatic circuit components to control the flow of compressed air between the air dryer 14 and the air reservoir primary 18. The pneumatic circuit protection valves are located inside the housing 16 to monitor the pneumatic circuits fed by the primary reservoir 18 and the secondary reservoir 12. A fault detection means is also located within the housing 16 to detect a failure of the pneumatic circuits that are fed by the primary and secondary tanks 8, 12 and in the case of a failure of these pneumatic circuits limit the speed of the heavy vehicle. With regard to Figure 1, this shows a three-pneumatic pneumatic loading system, from the technique __ ___l ._.-_ > V.; _ L ... ^ .. -_a «____ to« __ 3 »___ i _» ^! * t * _JSí_lJ ______. * "" ":: Above, relatively noRal for a brake system of a heavy-duty vehicle Most of the prior art compressed air systems for air brake applications in heavy vehicles use a primary reservoir 18, a secondary tank 12 and a supply tank 60 that are separated from the air dryer A compressor 20 feeds compressed air to an air dryer 62, which after flowing through the desiccant bed is fed to the remote supply tank 60. The supply tank 60 is connected to feed compressed air to the primary tank 18 and the secondary tank 12. The primary tank 18 and the secondary tank 12 supply pneumatic circuits that can control the vehicle's air brake system. the air pressure, the primary and secondary reservoirs each include a check valve 66 and 64, respectively, in their pneumatic connections to the supply tank 60. A pneumatic control tube 68 extends from the supply tank 60 to an air pressure regulator 70, mounted on the air compressor 20, which controls the loading and unloading of the air compressor. air 20. The secondary reservoir 12 also has a pressure protection valve of 85 psi (586.20 kPa) 72 and a pressure protection valve of 55 psi (379.33 kPa) 74 attached thereto. which feeds the accessories in the heavy vehicle. The feed reservoir 60 includes a safety valve 76 which is set to 150 psi (1035 kPa). The three reservoirs 12, 18 and 60 include a manual drain valve which can be used to drain liquid from its respective reservoir. Comparing Figures 1 and 2, the differences between the air dryer tank module 10 and the normal three-tank system are observed. The air dryer tank module 10 integrates components, eliminates pneumatic tubes and connections compared to the normal three-tank system as shown in Figure 1. The air dryer reservoir module 10 which is one of the brake air systems charging subsystems is proposed for use in heavy vehicles, such as tractors and trucks, and is configured as shown in Figures 2 and 3. The manufacture of the system of the air dryer tank module 10 is proposed by traditional methods. The air dryer reservoir module is different from the prior art in that it integrates components of the charging system in a manner that eliminates components, pneumatic tubes and pneumatic connections thereby reducing the failure modes. The air dryer reservoir module 10 is considered the first of its kind to use the ABS / EBS ECU braking system to communicate faults in the u system to the engine ECU in order to instruct the engine to limit the vehicle's speed. The concept of the air dryer reservoir module 10 eliminates the supply tank 60 thereby allowing the primary and secondary service tanks 5 and 18 to communicate directly with the integrated air dryer 14 through the protection valves. and 36. This allows the protection valves 35, 36 to be integrated in the air dryer module 10, reducing external components and tubes tires. Now with regard to Figures 4 and 5, the air dryer tank module 10 operates as follows. The charging air of the air compressor 20 enters the air dryer reservoir module 10 in its feed hole 31, flows through a purge valve 32 to the desiccant bed 33, fills the purge volume 34, flows through a purge port (not shown) and flows outward to a single check valve (not shown) . This represents the same charging cycle as the one used in the dryer Air AlliedSignal AD-9 or AD-IP. From the discharge of the single check valve, the charge air flows for the supply of the primary protection valve 35 and the secondary protection valve 36. The charge air pressure builds up until the protective valves 35 , 36 opens, allowing air to flow to the primary reservoir 18 and the secondary reservoir 12. The charge air pressure continues to accumulate until the pressure sensors 37 or a mechanical regulator (not shown) reach the free exhaust pressure. In the free exhaust pressure, the solenoid 5 in three directions 39 or the mechanical regulator opens, discharging the compressor 20 and opening the purge valve 32 to purge the air dryer 14. The purge cycle is the same as that of the AlliedSignal AD-9 or AD-IP air dryer. The configuration of the integrated component of the module air dryer reservoir 10 make it compatible with the operation of the integrated purge and purge system air dryer and the mechanical and electrical type regulators. This allows only one double-function electric solenoid to control the discharge function of the air compressor and purge the air dryer 14 using the primary and secondary service tanks 18 and 12, respectively. This configuration also allows both tanks 12, 18 to be purged simultaneously thereby reducing the total pressure drop of the system required to regenerate. the desiccant bed 33 with the operation of the purge type air dryer of the system. The use of pressure protection valves 35 and 36 instead of the individual check valves 66 and 64 reduces the cycle of the compressor 20. Without the use of check valves 64 and 66 the primary reservoir 18 and secondary deposit 12 are common to pressures by ¿& ~. ^ *. ^ J? * ^ * ^ **. __ ^ _ g¡ agg¡ | ¡§ ^ above the opening pressure of the protection valves 35, 36. Therefore, no pressure differentials develop between the primary reservoir 18 and the secondary reservoir 12 as It consumes the air. The 5 pressure differentials can be developed in the three-tank, normal systems, due to the inadequate size of the tanks and the use of accessory systems, causing the compressor to automatically connect before the air pressures in both tanks 12, 18 has 10 descended to the pressure of the automatic connection. The air dryer reservoir module 10 may be designed to use air from the service tank to purge the desiccant, i.e., the supply purge. The operation of the air dryer tank module 10 in a feed purge mode will be similar to that of an AlliedSignal AD-SP air dryer. The integrated pressure protection valves 35, 36 will eliminate the need for protection valves connected to the outside. Internal protection valves 35 and 36, 20 when opened will allow air to flow back to a special three-way system purge solenoid in two positions, located where the three-way solenoid 39 is in the design of integrated purge. The purge solenoid system in three directions, two 25 positions, special will be controlled by the EBS ECU with , ~ > * ~ *. * ^. . ^ -_ ^, ^^ _ .. - •• - ____ É_H_JÉrr- 77"JB & ¿* £ ¿* - * - • ^ - ^ tta- - ^ inputs from pressure sensors 37. The solenoid bleed The system will be designed to communicate a control signal to the compressor unloader 20 and the air dryer purge valve 32 independently.At the free exhaust pressure, the solenoid for purging the system will discharge the compressor and open the compressor. purge valve 32. the system purge solenoid will then close only the purge valve 32 after a predetermined amount of air from the system 10 is used to purge dryer desiccant bed 33. a pressure automatic connection, the solenoid for purging the system then it will charge the compressor 20 starting the cycle again Now with reference to Fig. 6, the mode of the air dryer tank module illustrated in Fig. 10 operates as follows: The air charge of the air compressor 20 enter to air dryer reservoir module 10 in its supply port 31, fills the purge volume 34 and flows outward to an individual check valve 13. The check valve 20 isolates the primary reservoir 18 and the secondary reservoir 12 from the outlet of the air dryer 14. An overpressure safety valve 21 which is set for 150 psi (1035 kPa) is located at the outlet of the air dryer 14. From the outlet of the individual check valve 13, the charge air it flows for s? - - ^. ^. ^, 1fMfflffir ^^^ a. ^^ *? 2 ** ^^ sj z '^ * -food Maax valve 35 primary protection and secondary protection valve 36. Charge air pressure builds up until the protection valves 35, 36 open, allowing air to flow to the primary reservoir 18 and secondary reservoir 12. the air pressure continuous charge accumulated in the output of the valve 13 until a mechanical governor 15, which is connected to the outlet of the check valve 13, reaches the free exhaust pressure. At the free exhaust pressure, which is set at 130 ± 5 psi (897 ± 34.5 kPa), the mechanical regulator 15 opens, providing a pressure drop signal across the line 19 to discharge the compressor 20 and provide a pneumatic signal along the line 17 to start the purge of the air dryer 14 with the compressed air contained in the purge volume 34. The compressor 20 remains discharged until the pressure of the regulator 15 falls below the connection pressure automatic, which is set to 105 psi (724 kPa). At the automatic connection pressure, the regulator 15 is closed and the compressor is charged to again supply compressed air with the inlet 31 of the air dryer 14. The primary protection valve 35 is set to open at 103 ± 3 psi (897 ± 21 kPa) and to close at approximately 95 psi (655 kPa). The secondary protection valve 36 is set to open at 109 ± 3 psi (752 kPa ± 21 kPa) and to close at approximately 100 psi (689.7 kPa). When both protection valves 35 and 36 are open, the primary reservoir 18 and the secondary reservoir 12 are in free hydraulic communication. The secondary reservoir 12 provides compressed air to a vehicle leveling feed hole through an accessory protection valve 41 which is set to open at 85 ± 3 psi (586 ± 21 kPa) and close at about 72 to 83 psi ( 497 to 572 kPa). The secondary reservoir 12 also provides compressed air to vehicle accessories through an accessory protection valve 43 which is set to open at 55 ± 3 psi (379 ± 21 kPa) and close at approximately 45 to 55 psi (310 to 379 kPa). The air dryer tank module 10 is designed to meet the requirements of regulation 13 of the EEC number and FMVSS 121. The tank module air dryer 10 is also designed to interact with the link J1939 engine serial / J1922 ABS system (EBS to allow limited the speed of the vehicle in the case of a failure of the brake system of the individual, primary or secondary circuit. The air dryer reservoir module 10 reduces the number of components of the installed OEM load subsystems, pneumatic tubes and connections as follows: main components of the system loading - four for the dryer tank module ! ^^^^^^^^^^^? ^^^^^^^^^ ^ ^^^^^ ^ ^ ^^^ air 10 compared to 13 for a system d, e three deposits; pneumatic tubes: three for the air dryer tank module 10 against six for a three-tank system; and pneumatic connections: 13 for the air dryer reservoir module 10 to 32 for a three-tank system. Figure 5 shows the air dryer tank module in a full service brake system. The system of the reservoir module of the air dryer 10 can be designed to communicate failures of the pneumatic circuit through the ABS / EBS ECU 50 to the serial link of the motor (J1922 / J1939) to instruct the motor to go into a mode "relaxed". The invention of this feature is to provide an "annoying" motivator for the operator to have the vehicle repaired. The system operates as follows: in the case of a failure of a pneumatic system that is fed by the primary reservoir 18 or the secondary reservoir 12, the integrated pressure detectors of the reservoir module of the air dryer 10 37 communicate the state of pressure from the system to the ABS / EBS ECU 50. The ECU instructs the engine control module (ECM) 52 to limit the speed of the vehicle if the vehicle is in excess of a certain limit. Now with reference to Figures 4 and 7 a secondary reservoir 12 with an integrated purge volume 34 is shown. ^^ j & A screen 53 separates the purge volume 34 from the secondary reservoir 12. An integrated tube 54 extends through the purge volume 34 to connect the reservoir 12 through the connections within the housing 16 to the air dryer 5 14. A connection 55 connects the purge volume 34 through the connections within the housing 16 to the air dryer 14. This construction eliminates external tubes for connecting the air dryer 14 to the purge volume 34 and the secondary reservoir 12. The external tubes have the potential leak points, and create the usual handling and assembly problems. The accumulation of the purge volume 34 necessary for the air dryer in the secondary reservoir 12 allows the use of a compact cartridge for the desiccant of the air dryer for purging the system and this minimizes the space required. The screen 53 has the tube 54 connected therethrough and the tube 54 extends through the purge volume 34 and ends at the head of the reservoir. The head of the tank has attached to this the housing 16 which is integrated with the dryer. air 14. The air dryer communicates with both volumes 12 and 34 through the separate ducts 54 and 55. With a leaky tank 12 or 18 the dryer tank module 10 described above will indefinitely reload the survival tank , by this means maintaining distance the spring brakes. The driver can choose operate the vehicle with limited braking efficiency for an unlimited time even if one of the tanks has no pressure. In another embodiment, the module of the drying tank 10 can be constructed to equalize the pressure 5 between the tanks 12 and 18, so that, if the vehicle is parked for a certain time, the pressure can not be filled, limited by this means. use of the vehicle with a tank with severe leaks. As shown in Figures 6 and 8 and described above, the pressure protection valves 35 and 36 are used to supply compressed air to the primary reservoir 18 and the secondary reservoir 12. The pressure protection valves 35, 36 are set to estimate the primary reservoir 18 first, provided that there is the same15 pressure inside the primary and secondary tanks. At the pressure of the total system the pressure protection valves 35, 36 are open, guaranteeing equal pressure in both primary and secondary tanks 18 and 12. However, the pressure that opens the pressure protection valve is dependent on the downstream reservoir pressure, therefore, if the reservoir pressures are not equal, the pressure protection valve having the highest downstream pressure will open first. Parking the vehicle at night or for a prolonged period of time may cause the pressures of the primary and secondary deposits are z & unbalance. During the recharging of the air system, the secondary reservoir 12 can charge before the primary reservoir 18. It may be desirable to limit the duration that the vehicle can be operated in the state where a reservoir 5 has sufficiently low pressure. By using a pressure equalization mechanism, such as a connection line with a convenient hole 57, the pressures in the tanks 12 and 18 slowly equalize, so that during the recharging of the system. air the primary reservoir 18 load first. In addition, if the primary reservoir 18 breaks or has a severe leak, the pressure in both reservoirs 12 and 18 will migrate to 0 psi (0 kPa); avoiding thereby to recharge the secondary reservoir 12 since the primary reservoir 18 will not recharge due to leakage. If the deposit secondary 12 breaks or has a severe leak, again the pressure in both tanks 12 and 18 will migrate to 0 psi (0 kPa); however, the primary reservoir 18 may be recharged, but the essential accessories and the air suspension will not be pressurized because the secondary reservoir 12 can not be recharged. The pressure equalization mechanism 57 will cause the pressure in both tanks 12 and 18 to be equal; loading by this means first the primary reservoir 18 and limiting the use of the vehicle after a serious leak in the primary or secondary reservoir 18 and 12. 25 *** ********

Claims (10)

1. An air supply system for a heavy-duty vehicle brake system comprises: a compressor for supplying compressed air; an air dryer connected to receive compressed air from the air compressor including a desiccant bed through which the compressed air can flow to provide a source of clean compressed air and 10 dry to operate the brake system, a secondary reservoir, a housing connected the air dryer and the secondary reservoir to each other as a unitary module, a primary reservoir located away from the secondary reservoir 15, control components located in the housing to control the air flow of the air compressor through the air dryer to charge the primary reservoir and the secondary reservoir with compressed air, a purge volume formed integrally with the secondary reservoir; and the control components also control the air flow of the purge volume through the desiccant bed of the air dryer to the atmosphere to purge the air dryer. | ^ § > ^ J ^^^^ g ^? J

2. The air supply system as claimed in claim 1, comprises: a pressure equalizing mechanism located between the secondary tank and the primary tank to equalize the pressure in the secondary deposit and the primary deposit.

3. The air supply system as claimed in claim 1, comprises: a primary valve for controlling the pneumatic protection located within the housing for controlling the pneumatic pressure fed to the primary reservoir; and a secondary valve for controlling the pneumatic protection located inside the housing to control the pneumatic pressure fed to the secondary reservoir.

4. A compressed air system for a heavy-duty vehicle comprises: an air compressor providing a source of compressed air, a housing having an inlet connected to receive compressed air from the air compressor, an air dryer clamped in a manner secure to the housing, a secondary reservoir for compressed air securely fastened to the housing forming with the housing and the air dryer a module, a primary reservoir of compressed air having a '^^^^^^^ pneumatic connection to the housing located away from the module, the module including control components and connections to control the flow of compressed air between the air dryer and the secondary reservoir of compressed air and the air reservoir compressed, primary; and a pressure equalizing mechanism located between the secondary tank and the primary tank to equalize the pressure in the secondary tank and the primary tank.

5. The compressed air system as claimed in claim 4, comprises: a purge volume formed integrally with the secondary reservoir; and the control components also control the airflow of the purge volume through the desiccant bed of the air dryer to the atmosphere to purge the air dryer.

6. An air dryer unit for providing compressed air from an air compressor in a heavy-duty vehicle comprises: an air dryer connected to receive compressed air from the air compressor, a first air tank separate from the air dryer, a housing containing components of the pneumatic circuit to control the flow of compressed air from J ---'--: "'the air compressor through the air dryer for the first tank having the air dryer and the first tank securely attached to it to secure the air dryer and the first tank together as a module 5. a second air reservoir having a pneumatic connection to the housing located remote from the first air reservoir, a first pressure protection valve located inside the housing to control the charge loading the first reservoir, a second reservoir valve. Pressure protection located inside the housing to control the load that loads the second tank; and a pressure mechanism located between the first tank 15 and the second tank to equalize the pressure of the first tank and the second tank.

7. A compressed air system for a pneumatic brake system for heavy vehicles comprises: an air compressor for feeding compressed air 20 when it is charged and for not supplying compressed air when it is discharged, a primary reservoir, a secondary reservoir located far from the primary reservoir, 25 an air dryer connected to receive air ^ tí * * »* ^ * * ^. , ........ JL - * ^. - ^^^^^ tftñfft, ^^., a_a »- ^ _ compressed air compressor including a desiccant bed through which compressed air can flow to provide a source of clean and dry compressed air to the primary reservoir and the secondary tank to operate the brake system and being connected to the secondary tank to form a tank module and the air dryer, a check valve located between the air dryer and the primary and secondary tanks and being part of the dryer module of air and the deposit; and a purge volume being a part of the secondary reservoir for purging the desiccant bed when the air compressor is discharged.

8. The compressed air system for a pneumatic brake system for heavy vehicle as claimed in claim 7 comprises: a pressure equalizing mechanism located between the secondary tank and the primary tank to equalize the pressure in the secondary tank and the tank primary.

9. The compressed air system for a pneumatic brake system for heavy vehicle as claimed in claim 8 comprises: a primary pressure-releasing valve being part of the air dryer module and the reservoir, being located between the outlet of the valve of retention and the primary deposit, and being set to open when the pressure "- ^ AM *" - A * ** applied exceeds a first pressure and to close when the applied pressure falls below a second lower pressure.

10. The compressed air system for a 5-tire system for heavy vehicle brakes as claimed in claim 9, comprises: a second pressure-releasing valve being part of the air dryer and reservoir module, being located between the outlet of the check valve and the secondary reservoir 10, and being set to open when the applied pressure exceeds a first pressure and to close when the applied pressure drops below a second lower pressure. fifteen