1
ANNEXURE
PATENT APPLICATION FOR
AIR FLOW CONTROL CUM AUTOMATIC ALARM DEVICE FOR PNEUMATIC
SUSPENSION SYSTEM FOR RAIL CARS
DESCRIPTION
The present invention relates to an additional feature in the Pneumatic Suspension
System in high speed EMU / DMU and Mainline passenger coaches , whereby any
failure of either Air Spring Assembly in a particular Bogie is automatically detected and
the train is automatically stopped.
PRESENT PNEUMATIC CONTROL SYSTEM OF AIR SPRING SUSPENSION IN EMU
/ DMU AND MAIN LINE COACHES
. The Pneumatic Control System of Air Spring Suspension System of EMU / DMU and
Mainline Coaches contains four separate Air Spring Assemblies and each Air Spring
Assembly maintains a correct air pressure limiting to 6 kg/cm2 corresponding to its
vertical minimum and maximum load range of 50 KN ( Minimum Tare Load ) and 150
KN ( Maximum Full Load ). The air pressure in each Air Spring is fed by MR pipe.
At present each coach in the Pneumatic Control System of Air Spring Suspension a Bi-
directional Air Flow Control Valve © , popularly known as Duplex Check Valve is
provided between the two Air Spring Assemblies in each Bogie. Whenever the pressure
differential between the two Air Springs in a Bogie reaches a value of 1.5 kg I cm2 the air
from one Air Spring Assembly is diverted to the other Air Spring Assembly through this
valve to maintain equilibrium in pressure between the two Air Spring Assemblies. This
ensures uniform height of both the Air Spring Assemblies in a Bogie.
NEW AUTOMATIC ALARM SYSTEM
The new Air flow cum Automatic Alarm Device provides an additional feature in the
Pneumatic Suspension System Controls in high speed coaches whereby any failure of
either Air Spring Assembly in a particular Bogie is automatically detected and the train is
automatically braked.
The compact design of the new Air flow cum Automatic Alarm Device integrates the
features of pressure compensation between two Air springs of consecutive bogies and
automatic detection of leakage in any of the airspring alongwith automatic braking of the
train.
In the lay out SK-103 the Pneumatic Control System of Air Spring Suspension has
been provided. In this system a new Air Control and Automatic Alarm Device (A-CAD ©)
has been incorporated which will do the dual function of the duplex check valve as well
as the automatic failure indication and Brake application valve. A three dimensional
view of the same is also shown vide our Sketch No. SK4-104.
With the help of A-CAD ©, in addition to the normal function of duplex check valve ( as
explained earlier) the device will also allow Brake Pipe pressure to be vented in case of
abnormal drop of the system pressure in the Air Spring Suspension thus allowing brakes
to apply. Further this has got a provision for high decibel alarm sound device which will
allow propagation of a hooter alarm sound to the driver / guard for locating the subject
coach / bogie in the train spontaneously. This venting of Brake Pipe pressure can also
be fed to driver's cabin through a suitable micro processor based control system as
system input.

2
The New Air flow cum Automatic Alarm Device would quickly identify the coach in
which failure takes place and to minimize further risk brake will be applied which will
slow down or stop the train to attend the problem.

3
ANNEXURE
WE CLAIM
1 With the help of the Air flow control cum Automatic Alarm Device failure of either Air
spring Assembly in a particular Bogie in the EMU / DMU or high speed mainline train is
automatically detected and the train is automatically stopped.
2.The failure in the air springs in a particular coach can cause a difference in height
between two ends of the coaches while the train is running. The automatic Brake
application would therefore reduce any chances of accident.
3. The design of the Alarm device is so compact that it can be fitted on to the existing
EMU / DMU coaches without having any extra demand on space envelope .
4 Since the complete Alarm device serves the dual function of a Duplex check valve for
pressure compensation between the two Air springs of the bogie system and automatic
alarm raising system to bring notice of driver / attendant, it saves a lot of idle time for the
identification of affected coach.
5 A three dimensional view of the Alarm device is shown in the Sketch No. SK-104.

The Air flow control cum automatic alarm device for pneumatic suspension system for Rail cars is a unique fail safe system design by stone India Ltd. to be used in passenger coach of indian
Railways. The new air flow control cum automatic alarm Device design takes care of any failures in suspension system and also applies brake simultaneously resulting in full safety of passenger along with no undue vibration in the coach.
It is a very compact and requires no additional mouting since it is integrated/combined with duplex check value. This unique design will be manufacured by repeated items for easy maintenance/replacement. This is also unique in nature.