Bendix QR-L INLINE QUICK RELEASE VALVE User Manual

®

Bendix® QR-L™ Inline Quick Release Valve

SD-03-906

WRENCH

FLAT

SUPPLY PORT

(MALE PIPE

THREAD)

EXHAUST

WRENCH

FLAT

DELIVERY

PORT

Direct Mount QR-L™ V alve

FIGURE 1 - QR-L™ INLINE QUICK RELEASE VALVE

DESCRIPTION

The Bendix® QR-L™ quick release valve is similar to standard
quick release valves such as the QR-1™, QR-N™, and
QRN-2™. Its purpose is to “speed up” the release of air from
air lines and devices it is attached to. Although primarily
intended to enhance air system performance by rapidly
exhausting supply or control air pressure from vehicle air
lines, it can be used in a variety of different applications. It
is uniquely suitable as an air system performance
enhancement due to its 0 psi crack and differential pressure.
Supply and delivery pressure is the same throughout the air
pressure range. A typical air system application for the
QR-L™ valve is illustrated in figure 3.

The QR-L™ valve is non-serviceable. It incorporates a single
supply and delivery port along with two exhaust ports. T wo
versions of the QR-L™ valve are available as illustrated in
figure 1. Male pipe threads at the supply port, on the direct
mount version, allow installation in another air device. A
1-1/8” machine thread on the exterior of the supply port and
a 3/8” PT female air connection on the second version
permits installation in a bracket or a hole in a frame or
cross member on the vehicle.

NUT & STAR

WASHER

SUPPLY PORT
(FEMALE PIPE

THREAD)

EXHAUST

DELIVERY

PORT

Frame or Bracket Mount QR-L™ V alve

BODY

CRIMPED TO

CAP

SUPPLY

PORT

CAP

3 AIR CHANNELS

(0 PSI CRACK &

DIFFERENTIAL)

FIGURE 2 - QR-L™ INLINE QUICK RELEASE VALVE

An arrow , embossed in the cast body , indicates the flow of
air through the valve, from supply to delivery .

Supply port: 1/2"-Male P.T . or 3/8"-Female P.T.
Delivery ports: 1/2" Female P.T .
Weight: .6 lb.
Material: Die cast zinc
Operating pressure: 150 psi maximum
Operating temperature: -40° to 200° F

O-RING

BODY

DELIVERY

DIAPHRAGM

EXHAUST

DIAPHRAGM

PORT

1

Service

Brake

Valve

Tractor

Protection

Valve

Control

Line QR-L

Valve

Exhaust

Supply

™

Trailer

Control

Valve

Trailer

Supply Valve

FIGURE 3 TYPICAL QR-L™ INLINE QUICK RELEASE VAL VE
AIR SYSTEM APPLICA TION

Supply Line

QR-L

Valve

™

OPERATION

0 psi Crack & Differential Pressure

Unlike standard quick release valves, the QR-L™ valve
maintains the same pressure at the supply and delivery
ports (0 psi crack and differential) throughout the entire
pressure range during both apply and release modes. Three
radial channels in the cap, along with a specially shaped
diaphragm, provide the QR-L™ valve with this feature.

Apply

When air pressure enters the supply port, it causes the
center portion of the diaphragm to seal the exhaust in the
body . Supply air pressure simultaneously forces the edges
of the diaphragm away from its seat on the cap, allowing air
to flow freely out the delivery port. Delivery pressure is the
same as supply pressure.

Balance

When delivery air pressure (pressure beneath diaphragm)
is equal to supply air pressure above the diaphragm, the
outer edges of the diaphragm seat against the cap. The
exhaust remains sealed because air pressure bears against
the center portion of the diaphragm from one side only .

Exhaust

Supply

Delivery

Diaphragm

Exhaust

FIGURE 5 QR-L™ INLINE QUICK RELEASE V ALVE BALANCED
MODE

Exhaust

Supply

Delivery

Diaphragm

Exhaust

FIGURE 6 QR-L™ INLINE QUICK RELEASE V ALVE RELEASE
MODE

Release

When air pressure is removed or reduced rapidly at the
QR-L™ valve supply port, the air pressure on the delivery
side of the diaphragm holds the outer edge of the diaphragm
against its seat on the cap while simultaneously moving
the center portion away from the exhaust port in the body .
Air from the delivery port flows out the exhaust ports. If air
pressure is reduced slowly at supply port, air may not flow
out the exhaust ports.

When delivery air pressure is fully exhausted, the diaphragm
will return to its natural state, with its outer edges seated
on the cap and the center portion seated against the exhaust
in the body.

WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURY OR DEATH:

Delivery

Diaphragm

Exhaust

FIGURE 4 QR-L™ INLINE QUICK RELEASE VA LVE AIR APPLIED
TO SUPPL Y PORT

2

When working on or around a vehicle, the following
general precautions should be observed at all times.

1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.