Arrangement and method for degassing a pump

An arrangement configured to control a gas flow separated from a suspension of medium consistency pulp in a pulp treatment apparatus, the arrangement comprising:

• a first pump and a second pump, wherein the first pump pumps the suspension as the suspension flow to a first reactor and the second pump pumps the suspension as the suspension flows from the first reactor to a second reactor, wherein the second pump is a degassing centrifugal pump with a degassing system, and
• the degassing system comprises:
• a degassing conduit configured to receive gases from the second pump;
• a degassing valve connected to the degassing conduit and the degassing valve is configured to regulate a pressure difference in a flow of the gases between an inlet of the second pump and the degassing conduit, and
• a pressurized degassing vessel downstream of the degassing valve in the flow of the gases through the degassing conduit, wherein the pressurized degassing vessel is pressurized to above atmospheric pressure in an overpressure condition, and the pressurized degassing vessel includes an inlet and an outlet, wherein the outlet of the degassing vessel is connected to a pressure control valve configured to maintain the overpressure condition of the degassing vessel.