A pressure sensing device adapted for having a liquid flowing there through and for sensing the pressure of said liquid. The device has a casing being fluid-tightly divided into a first and a second chamber by a flexible, impermeable wall. The first chamber has a first opening for the liquid, said opening being placed at the lower part of the chamber, and a second opening for the liquid, said opening being placed at the top of the first chamber. The second chamber has a measuring port, which is connectable to a pressure transducer for bringing the second chamber into gas-tight communication with the pressure transducer. The device has a first orifice to permit the liquid to flow into and out of the device, the orifice being placed at the upper part of the device at a higher level than the second opening. A first channel is connecting the first orifice with the first opening. A second orifice permits the liquid to flow out of and into the device and is placed at the lower part of the device at a lower level than the first opening. A second channel connects the second opening with the second orifice.
