A volumetric machine acting on an operating fluid, comprising: - a first toothed wheel comprising a first group of teeth that identify interposed between them a first plurality of compartments for the operating fluid; - a second toothed wheel comprising a second group of teeth intended to engage with the teeth of the first group ; - a casing that defines a housing for positioning the first and the second toothed wheel ; - a path that extends along a section of said casing and that places in fluid communication at least two compartments of said first plurality ; said volumetric machine being a pump or fluid dynamic motor; characterised in that the casing comprises at least one first channel distinct from said path ; said first channel and said path do not intersect; at least in a predetermined configuration assumed by the first wheel : - the first channel places in fluid communication a first and a second compartment of said first plurality which are consecutive and at least partially delimited by a same tooth of the first group ; - at least the first compartment of the first plurality being distinct from the compartments of the first plurality licked by said path ; - said second compartment being licked by the path ; - said first compartment being placed upstream of the second compartment , when the machine is operating as a pump, and of the compartments of the first plurality licked by said path . - a first toothed wheel comprising a first group of teeth that identify interposed between them a first plurality of compartments for the operating fluid; - a second toothed wheel comprising a second group of teeth intended to engage with the teeth of the first group ; - a casing that defines a housing for positioning the first and the second toothed wheel ; - a path that extends along a section of said casing and that places in fluid communication at least two compartments of said first plurality ; said volumetric machine being a pump or fluid dynamic motor; characterised in that the casing comprises at least one first channel distinct from said path ; said first channel and said path do not intersect; at least in a predetermined configuration assumed by the first wheel : - the first channel places in fluid communication a first and a second compartment of said first plurality which are consecutive and at least partially delimited by a same tooth of the first group ; - at least the first compartment of the first plurality being distinct from the compartments of the first plurality licked by said path ; - said second compartment being licked by the path ; - said first compartment being placed upstream of the second compartment , when the machine is operating as a pump, and of the compartments of the first plurality licked by said path . - the first channel places in fluid communication a first and a second compartment of said first plurality which are consecutive and at least partially delimited by a same tooth of the first group ; - at least the first compartment of the first plurality being distinct from the compartments of the first plurality licked by said path ; - said second compartment being licked by the path ; - said first compartment being placed upstream of the second compartment , when the machine is operating as a pump, and of the compartments of the first plurality licked by said path . <EOS>