The present invention relates to a positive displacement machine.
Positive displacement machines have been widely used in practice. Such positive displacement machines as piston pumps or rotary pumps are composed of a great number of separate parts, and for this reason they are very expensive and bulky. Relatively simple gear pumps which are used when it is necessary to provide a high pressure, are even more expensive inasmuch as voluminous sealing elements are provided on the side surfaces of the gears. They are not always satisfactory in operation, and the construction costs of high pressure gear pumps are great.