1 - Accessories of test stand
V1= Pressure reducing valve of the stand supply circuit.
V2 = Pressure regulating valve of the test circuit (1).
V3 = Pressure regulating valve of the test circuit (2).
M5 = Pressure indicator manometer of the test stand supply circuit, with 0.2 bar scale divisions.
M1; M2 = Pressure indicator manometer for the test circuits (1) and (2) with 0.2 bar divisions.
T1; T3; T7; T9; T10; T1; T13 = Stopcocks (taps).
R25 = 25 liter air reservoir of the stand supply circuit.
R1 = 1 liter air reservoir of the test circuits.
(1); (2) Test connections.
2 - Visual inspection
Check the cylinder for external damage.
The relieve screw must be in the de-application position (suspension fluid reservoir).
3 - Connect the combined cylinder to the test stand
Quick clamping device (1) of the test stand at connection 11.
Quick clamping device (2) of the test stand on connection 12.
Open taps T7; T9; T10; T12; and T13. Close the other taps.
Operate the pressure reducing valve V1 e apply 9 bar in the test stand supply circuit. Confirm the pressure on manometer M5.
B42.10-0374-12
4 - Test the tightness
On the service brake diaphragm cylinder
Fully depressurize the pressure chamber of the spring accumulator. To do so, open the tap T3 until the manometer M2 indicates “zero” bar.
Close the tap T3.
Pressurize and relieve the pressure in the service brake diaphragm cylinder two or more times with a pressure of 8.5 bar by means of the regulating valve V2 and relieving the pressure by means of the tap T1. Control the applied pressure observing manometer 1.
This procedure has the purpose to accommodate the brake cylinder components.
Apply 5 bar of pressure to the membrane cylinder via the regulating valve V2. Observe the pressure applied to the manometer M1 and check for leak tightness by applying neutral soap foam to the intermediate flange and vent tube (WABCO cylinders). The pressure indicated on the manometer M1 may decrease, at maximum, 0.1 bar in two minutes.
Check if there is passage of pressure from service brake pressure chamber to the accumulator spring chamber. The manometer M2 connected to the suspension fluid reservoir pressure cell must not indicate any pressure.
Repeat the test operations applying 1.5 bar pressure, with quicker pressure application and relieving the pressure by means of the taps T1 and T3.
5 - on the spring accumulator:
De-pressurize the pressure chamber of the spring accumulator. To do so, close the regulating valve V2 until the manometer M1 shows “zero” bar.
Apply 8.5 bar pressure to the spring accumulator pressure cell by means of the regulating valve V3. Observe the pressure applied to the manometer M2.
Fully screw-in the spring accumulator's relieve screw.
Close the valves T2 and T3 and check the tightness of the assembly applying neutral soap foam. The pressure on the manometer M1 may decrease, at maximum, 0.1 bar in two minutes.
Apply 4.5 bar pressure to the spring accumulator pressure cell by means of the regulating valve V3. Observe the pressure applied to the manometer M2.
Close the valve T3 and check the tightness of the assembly applying neutral soap foam. The pressure on the manometer M2 may decrease, at maximum, 0.1 bar in two minutes.
Check if there is passage of pressure from the service brake pressure chamber to the accumulator spring chamber. For that, keeping 4.5 bar pressure on the manometer M2, the manometer M1 must not indicate any pressure at all.
Open taps T1 and T3. If air leaks are found, disassemble the combined cylinder and replace the damaged components.
6 - Test the operation
Apply 7 bar pressure to the spring accumulator by means of the regulating valve V3 and relieve the pressure by means of the valve T3 several times, controlling the pressure applied on the manometer M2 and observing the smoothness of displacement and the stroke of the combined cylinder rod.
7 - Relieve pressure of the spring accumulator
Close the regulating valve V3 fully depressurizing the spring accumulator pressure cell. The manometer M2 will have to indicate "zero" bar.
Slowly pressurize the spring accumulator pressure cell by means of the regulating valve V3 until the manometer M2 indicates 5.4 bar. The combined cylinder rod must be completely recoiled with the pressure between 4.8 and 5.4 bar.
After completing the test, apply 7 bar pressure to the spring accumulator pressure cell by means of the regulating valve V3 and unscrew the brake relief screw. At the end of its stroke, the screw will have to be turned manually until the stop.
8 - Remove the cylinder from the workbench
Fully depressurize the combined cylinder by means of the regulating valve V3 observing the pressure indicated on the manometer M2.
Detach the fast couplings of the connections 11 and 12 and protect the combined cylinder ports appropriated plastic plugs. The vent orifice of the combined cylinder can be protected with a piece of adhesive tape.
B42.10-0341-11