BENDIX SD-03-901 Manuel D’Utilisation

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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