| 摘要 |
<p>The valve unit comprises a body (20) with a valve (80, 81) for controlling communication between a supply chamber (C) which is intended to be connected to a compressed-air supply (3) and an outlet aperture (122) connected to a brake-operating pipe of a trailer. The valve (80, 81) is operable as a result of an increase in pressure in a first operating chamber (A) and/or in a second operating chamber (B) defined in the body (20). The valve unit is provided with a safety valve device (200) adapted to put the first and second operating chambers (A, B) into communication with each other when the pressure in the first chamber (A) falls below a predetermined value during service braking.</p> |
