Bendix Commercial Vehicle Systems QR-1 QUICK RELEASE VALVES 5/10 - 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 confi guration 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
confi guration 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 fl ows 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