SD-03-1151
Bendix® RE-6™ and RE-6NC™ Relay Valves
EMERGENCY
PISTON
O-RING
SEALING
RING
RE-6™
Valve
MOUNTING
FLANGE
RE-6™ & RE-6NC™
Valves
RESERVOIR
PORT (2)
RE-6NC™ VALVE
ID TAG ATTACHED
SEE (FIGURE 2)
RELAY PISTON
SERVICE
PORT
INLET AND
EXHAUST
VALVE
EMERGENCY
SUPPLY PORT
CHECK VALVE
SPRING
SPRING |
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DIAPHRAGM |
WASHER |
CAP |
SCREW |
SCREW |
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CHECK VALVE |
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DELIVERY |
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PASSAGE |
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SERVICE |
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PORT |
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EMERGENCY
PORT
CHECK VALVE
DELIVERY RE-6NC™ PASSAGE NOT
DELIVERY PORTS PRESENT Valve
(4)
CHECK
VALVE
NOT
PRESENT
FIGURE 1 RE-6™ & RE-6NC™ RELAY VALVES
RE-6™ VALVE DESCRIPTION
The RE-6™ valve is used in dolly and trailer brake systems. It is a dual function valve, combining the functions of a relay valve and an emergency valve.
The relay function is identical to that of a relay valve, a remotely controlled brake valve. Control pressure from the towing vehicle is routed through the trailer service line and
RE-6NC SPECIAL
XXXXXX
SVC. REPL. XXXXXX
FIGURE 2 RE-6NC™ RELAY VALVE SPECIAL IDENTIFICATION TAG
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CONTROL LINE
FRONT
SUPPLY LINE
Service Brake Chamber
Slack Adjuster
Trailer Gladhand
R-12P™ |
Single Check |
Reservoir |
RE-6™ |
Valve |
Valve |
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Valve |
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Bulkhead |
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Drain |
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Valve |
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SV-4™
Valve
RE-6™ RELAY VALVE DOLLY SYSTEM CONFIGURATION
CONTROL LINE
FRONT
SUPPLY LINE
Service Brake Chamber
Slack Adjuster
Trailer Gladhand
R-12P™ |
Single Check |
Reservoir |
RE-6NC™ |
Valve |
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Valve |
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Valve |
Bulkhead |
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PR-3™ |
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Single Check |
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Valve |
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Valve |
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SV-4™ |
Drain |
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Valve |
Valve |
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RE-6NC™ RELAY VALVE DOLLY SYSTEM CONFIGURATION
FIGURE 3 - RE-6™ & RE-6NC™ RELAY VALVES SYSTEM CONFIGURATION
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on to the relay portion of the valve. The emergency function of the valve automatically applies full trailer reservoir air pressure to the trailer chambers when the trailer supply pressure falls below a predetermined minimum value.
The RE-6™/RE-6NC™ relay emergency valve may be flange or reservoir mounted. Ports are clearly identified for delivery, service, emergency (supply) and reservoir lines.
RE-6NC™ VALVE DESCRIPTION
The RE-6NC™ valve is a special non-charging relay emergency valve. It is used on dollies to comply with FMVSS 121. The RE-6NC™ valve eliminates the need for a protected reservoir to provide the release air for the trailer spring brakes when the following requirements are met:
-The trailer supply line must be 70 psi minimum with any leakage-type service system failure.
-The parking brake must not drag at trailer supply line pressures above 70 psi.
The relay function of the RE-6NC™ valve is identical to that of the RE-6™ valve, serving the dolly or trailer system as a remote controlled brake valve. The emergency function of the valve automatically applies full trailer reservoir air pressure to the trailer or dolly chambers when the trailer supply pressure falls below a predetermined minimum value. The major difference between the RE-6™ and the RE-6NC™ valve is that the RE-6NC™ valve allows supply pressure (initial charge) to release the spring brakes before the dolly or trailer reservoir(s) is filled.
RE-6™ & RE-6NC™ VALVE SYSTEM CONFIGURATION
In the RE-6™ valve dolly system, the supply air flows to the RE- 6™ valve, passes through the valve, holding the chambers in the apply position while simultaneously filling the reservoir. In the RE-6NC™ valve dolly system, reservoir air is not supplied through the RE-6NC™ valve, as it is in the RE-6™ valve system. The supply air flows to the RE-6NC™ valve, acts upon the emergency piston, pushing the emergency piston toward the inlet / exhaust valve seat. System pressure in the chambers and reservoir are still at 0 psi in the RE-6NC™ valve system, allowing for faster trailer pull-away. In the RE-6NC™ valve system, air is also flowing to the PR-3™ valve, which will allow the air to flow on to the reservoir at a pressure setting of about 70 psi. The major difference between the RE-6™ valve and the RE-6NC™ valve is that the RE-6NC™ valve does not require the system to charge the reservoir to a predetermined psi before drive away is allowed. Refer to Figure 3.
EMERGENCY
SUPPLY
45 PSI
RESERVOIR
45 PSI
CHAMBERS
45 PSI
RE-6™ Relay Valves
45 PSI
0 PSI
0 PSI
RE-6NC™ Relay Valves
FIGURE 4 RE-6™ & RE-6NC™ RELAY VALVES CHARGING BELOW 45 PSI
CHARGING THE RE-6™ & RE-6NC™ VALVES BELOW 45 PSI
When the air brake system is charging below 45 psi, emergency supply air enters the RE-6™ and RE-6NC™ valves emergency port. In the RE-6™ valve the air acts on the check valve and the emergency piston. In the RE-6NC™ valve the air acts on the emergency piston, because there is no check valve present. This allows for faster drive away (reference FMVSS 121 regulation). In the RE-6™ valve, the supply air is forced past the check valve, flowing through the emergency piston shoulder and past the inlet / exhaust valve. The air flows to the upper portion of the valve, underneath the relay piston and out to the service brake chambers while simultaneously filling the reservoir with the same air that is passing through the emergency piston. In the RE-6NC™ valve, air is only acting upon the emergency piston. The check valve is not present. In replacement of the check valve, the RE-6NC™ valve uses a reservoir control valve (the Bendix® PR-3™ valve), to allow the reservoir to be filled. The PR-3™ valve is totally separate from the RE-6NC™ valve, but is necessary for proper operation of the RE-6NC™ valve. Air acts on the PR-3™ valve piston, but will not flow on to the reservoir until about 70 psi. Refer to Figure 4.
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EMERGENCY |
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SUPPLY |
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45<>60 PSI |
RESERVOIR |
EMERGENCY |
RESERVOIR |
SUPPLY |
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45<>60 PSI |
60 PSI |
60 PSI |
45<>60 PSI |
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CHAMBERS |
CHAMBERS |
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HOLDING |
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0 PSI |
RE-6™ Relay Valve |
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RE-6™ Relay Valve |
45<>60 PSI |
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60 PSI |
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0 PSI |
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0 PSI |
0 PSI |
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0 PSI |
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RE-6NC™ Relay Valve |
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RE-6NC™ Relay Valve |
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FIGURE 6 RE-6™ & RE-6NC™ RELAY VALVES CHARGING |
FIGURE 5 RE-6™ & RE-6NC™ RELAY VALVES CHARGING |
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HOLD POSITION |
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ABOVE 60 PSI |
RE-6™ & RE-6NC™ VALVES CHARGING HOLD POSITION
In the RE-6™ valve, as pressure increases in the reservoir, the emergency piston is being pushed toward the seat on the inlet and exhaust valve. When the emergency piston reaches the seat of the inlet / exhaust valve, air is trapped between the new seal and the chambers, holding the chambers in the apply position. The check valve in the RE-6™ valve will continue to remain open, charging the reservoir. In the RE-6NC™ valve, air is acts on the emergency piston, but there is still 0 psi in the reservoir and the chambers. Air is also acting on the piston in the PR-4™ valve, but still has not reached the opening pressure of 70 psi. Refer to Figure 5.
CHARGING THE RE-6™ & RE-6NC™ VALVES ABOVE 60 PSI
In the RE-6™ valve, as pressure increase beyond 60 psi, the emergency piston and the inlet / exhaust valve, move from the seat of the primary piston, opening the exhaust valve to atmosphere allowing the service chambers to be exhausted. The air will flow from the service chambers, back through the RE-6™ valve and out the exhaust of the RE-6™ valve,
allowing drive away. In the RE-6NC™ valve, air is still acting upon the emergency piston, but there is no pressure in the reservoir and the chambers. The emergency piston and inlet / exhaust valve have moved to the exhaust position, opening the exhaust portion of the valve to atmosphere. The PR-3™ valve remains closed until reaching 70 psi, allowing air to flow to the reservoir. Refer to Figure 6.
CHARGING THE RE-6NC™ VALVE ABOVE 70 PSI
Once system pressure reaches 70 psi, the PR-3™ reservoir control valve will open charging the reservoir(s). Simultaneously the emergency piston and inlet / exhaust valve of the RE-6NC™ valve is kept away from the seat of the primary piston (keeping the exhaust valve open to atmosphere). This is the major difference between the RE-6™ valve and the RE-6NC™ valve. The RE-6NC™ valve allows for quicker drive away, since the reservoir does not need to be filled before the brakes are released. Refer to Figure 7.
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