| 摘要 |
The present invention concerns a valve arrangement to maintain a pre-determined pressure in a cooling system in a vehicle (1). The valve arrangement (19) comprises a pressurised air passage (25 pressurised air is delivered to an internal compartment (12a) at the cooling system and a piston (23) that is arranged such that it can be displaced between an open condition and a closed condition in which it blocks the pressurised air passage (25). The piston (23) comprises a first piston area (a1) that is in contact with a medium in the said internal compartment (12a) of the cooling system and a second piston area (a2) that is in contact with pressurised air with an essentially constant pressure (p2). The first piston area (a1) and the second piston area (a2) are dimensioned such that the piston (23) is displaced towards the open condition when the pressure (p1) in the said internal compartment (12a) in the cooling system does not exceed a pre-determined pressure (p0), and towards the closed condition when the pressure (p1) in the said internal compartment (12a) in the cooling system exceeds the pre-determined pressure (p0). |
