Bendix Commercial Vehicle Systems QRV QR-1 QUICK RELEASE VALVES 7/06 - Manual

1
SD-03-901
DESCRIPTION
The function of the quick release valve is to speed up the
exhaust of air from the air chambers. It is mounted close to
the chambers it serves. In its standard configuration the
valve is designed to deliver within 1 psi of control pressure to
the controlled device; however, for special applications the
valve is available with greater differential or zero hysteresis.
QR-1
™ valves also come with optional noise reducing foam
crosses or silencers.
Reference Figure 1, two styles of quick release valves are
available and are functionally the same; the QRV
™ valve,
which is of older design and utilizes a spring and spring
seat, and the QR-1
™ valve, which in its standard configura-
tion does not employ a spring or spring seat.
(Note: QR-1 ™ valves with a pressure differential employ a
spring and spring seat.)
Porting consists of one supply port, two delivery ports and
one exhaust port.
OPERATION
When a brake application is made, air pressure enters the
supply port; the diaphragm moves down, sealing the
exhaust. At the same time, air pressure forces the edges of
the diaphragm down and air flows out the delivery ports.
When air pressure being delivered (beneath the diaphragm)
equals the pressure being delivered by the brake valve (above
the diaphragm), the outer edge of the diaphragm will seal
against the body seat. The exhaust port is still sealed by
the center portion of the diaphragm when the supply air is
released; the air pressure above the diaphragm is released
back through the brake valve exhaust; air pressure beneath
the diaphragm forces the diaphragm to rise, opening the
exhaust, allowing delivery air to exhaust.
FIGURE 1
Bendix ® QRV ™ and QR-1 ™ Quick Release Valves
QR-1 ™ Quick Release Valve QRV ™ Quick Release Valve
Supply Port
Delivery Port
Delivery Port
Exhaust Port
O-Ring
Cover
Spring
Supply Port
Delivery
Port
Delivery Port
O-Ring
Cover
Body QR-1 ™ Quick
Release Valve
Diaphragm
QRV ™ Quick
Release Valve
Exhaust Port
Diaphragm