The blow-by gas treating device 100 has a main structure portion 101 which separates oil OL from the blow-by gas BG and an outlet portion 40 which supplies gas G having been separated from the blow-by gas BG to an intake system. The main structure portion 101 has a first blow-by gas taking-in portion 111, a second blow-by gas taking-in portion 112, a separating portion 330 which separates the blow-by gas BG into oil OL and gas G, a first oil guiding portion 151 which guides the oil OL to a front side, a second oil guiding portion 152 which guides the oil OL to a rear side, a first oil drain 161 which discharges the oil OL into the engine, and a second oil drain 162 which discharges the oil OL into the engine.

The blow-by gas treating device 100 has a main structure portion 101 which separates oil OL from the blow-by gas BG and an outlet portion 40 which supplies gas G having been separated from the blow-by gas BG to an intake system. The main structure portion 101 has a first blow-by gas taking-in portion 111, a second blow-by gas taking-in portion 112, a separating portion 330 which separates the blow-by gas BG into oil OL and gas G, a first oil guiding portion 151 which guides the oil OL to a front side, a second oil guiding portion 152 which guides the oil OL to a rear side, a first oil drain 161 which discharges the oil OL into the engine, and a second oil drain 162 which discharges the oil OL into the engine.

A coalescence separator for separating liquid droplets from a gas flow has a gas inlet and a gas outlet. A multi-layer structure of a plurality of individual layers of a coalescence filter medium is arranged between the gas inlet and the gas outlet, wherein the coalescence filter medium is provided with a glass fiber paper with glass fibers. The individual layers of the coalescence filter medium each have an individual layer thickness of more than 0.8 mm and maximally 5 mm, a grammage of greater than 80 g/m.sup.2 and less than 500 g/m.sup.2, and an air permeability of 350 l/m.sup.2s to 1,800 l/m.sup.2s. The multi-layer structure has between 2 and 80 of the individual layers.

A coalescence separator for separating liquid droplets from a gas flow has a gas inlet and a gas outlet. A multi-layer structure of a plurality of individual layers of a coalescence filter medium is arranged between the gas inlet and the gas outlet, wherein the coalescence filter medium is provided with a glass fiber paper with glass fibers. The individual layers of the coalescence filter medium each have an individual layer thickness of more than 0.8 mm and maximally 5 mm, a grammage of greater than 80 g/m.sup.2 and less than 500 g/m.sup.2, and an air permeability of 350 l/m.sup.2s to 1,800 l/m.sup.2s. The multi-layer structure has between 2 and 80 of the individual layers.

An oil return valve for a crankcase ventilation system of an internal combustion engine is provided that is essentially situated in the crankcase (3) and includes a valve cylinder (1) and at least one valve pipe (2).

An oil return valve for a crankcase ventilation system of an internal combustion engine is provided that is essentially situated in the crankcase (3) and includes a valve cylinder (1) and at least one valve pipe (2).

A centrifugal separator is configured to separate liquid and solid particles from a flow of gas generated by a machine. The centrifugal separator includes a centrifugal rotor, a hydraulic drive arrangement configured to rotate the centrifugal rotor, a hydraulic connection for connecting the hydraulic drive arrangement to a hydraulic circuit of the machine, and a connecting portion for connecting the centrifugal separator to the machine. The hydraulic connection is arranged on the connecting portion, and the connecting portion is configured to be inserted into a connecting aperture of the machine. A machine includes the centrifugal separator.

A centrifugal separator is configured to separate liquid and solid particles from a flow of gas generated by a machine. The centrifugal separator includes a centrifugal rotor, a hydraulic drive arrangement configured to rotate the centrifugal rotor, a hydraulic connection for connecting the hydraulic drive arrangement to a hydraulic circuit of the machine, and a connecting portion for connecting the centrifugal separator to the machine. The hydraulic connection is arranged on the connecting portion, and the connecting portion is configured to be inserted into a connecting aperture of the machine. A machine includes the centrifugal separator.

An internal combustion engine is provided with: two intake pipe portions for guiding intake air to two banks; and a blow-by gas recirculation pathway for leading blow-by gas to the two intake pipe portions from a cylinder head or a crank case that includes the two banks. The blow-by gas recirculation pathway includes a distribution passage which is provided between the two intake pipe portions, and which distributes the blow-by gas and allows the same to flow to the two intake pipe portions.

An internal combustion engine is provided with: two intake pipe portions for guiding intake air to two banks; and a blow-by gas recirculation pathway for leading blow-by gas to the two intake pipe portions from a cylinder head or a crank case that includes the two banks. The blow-by gas recirculation pathway includes a distribution passage which is provided between the two intake pipe portions, and which distributes the blow-by gas and allows the same to flow to the two intake pipe portions.