Multi-stage electric gas pump

A multi-stage electric gas pump, comprising:

• a driving mechanism;
• an eccentric shaft including a main body having a longitudinal axis and one or more eccentric portions connected to the main body, and the eccentric shaft being driven by the driving mechanism so that the one or more eccentric portions perform circular movement around the longitudinal axis;
• a first cylinder, a second cylinder, and a third cylinder in mechanical cooperation with the eccentric shaft, wherein the one or more eccentric portions include a first eccentric portion and a second eccentric portion configured so that, in operation, the circular movement of the first and second eccentric portions cause the second cylinder to discharge gas while the first cylinder and the third cylinder draw in gas, and the second cylinder to draw in gas while the first cylinder and the third cylinder discharge gas;
• and
• wherein the first cylinder, the second cylinder, and the third cylinder are in mechanical cooperation with the eccentric shaft by way of a plurality of cranks,
• wherein a first crank of the plurality of cranks connects a first piston in the first cylinder and a second piston in the second cylinder to the first eccentric portion of the eccentric shaft, the first crank having a first end and a second end, the first end being connected to the first eccentric portion, and the second end being connected by way of a first cam bearing to at least one of a first piston rod of the first piston, or a second piston rod of the second piston, the first cam bearing being offset from the first eccentric portion, wherein the second piston rod and the first piston rod are connected to each other away from the first eccentric portion;
• and
• wherein a second crank of the plurality of cranks connects a third piston in the third cylinder to the second eccentric portion of the eccentric shaft, the second crank having a first end and a second end, wherein the first end of the second crank is connected to the second eccentric portion, and the second end of the second crank is connected by way of a second cam bearing to a third piston rod of the third piston.

A portable high pressure calibration device, comprising:

• a multi-stage electric gas pump including:
• an eccentric shaft including a main body having a longitudinal axis, a first eccentric portion, and a second eccentric portion, wherein the first eccentric portion and the second eccentric portion are fixed on the main body, the eccentric shaft is driven by a driving mechanism to produce a first circular movement of the first eccentric portion around the longitudinal axis and a second circular movement of the second eccentric portion around the longitudinal axis, and the second circular movement is synchronized with the first circular movement;
• and
• a plurality of cylinders each including a piston rod and a chamber, wherein a first piston rod of a first cylinder and a second piston rod of a second cylinder are in mechanical cooperation with the first eccentric portion by way of a first crank, the second piston rod and the first piston rod being connected to each other away from the first eccentric portion;
• wherein the first crank has a first end and a second end, the first end of the first crank being connected to the first eccentric portion, and the second end of the first crank being connected by way of a first cam bearing to at least one of the first piston rod or the second piston rod, the first cam bearing being offset from the first eccentric portion.