Pressure gradient pump

An apparatus comprising:

• a conduit comprising a first end having a first flange around a first opening, a second end having a second flange around a second opening, and a body between the first end and the second end having a third opening in molecular flow communication with the first opening and the second opening, where the first opening has a first cross-sectional area and the second opening has a second cross-sectional area;
• a pumping unit in molecular flow communication with the third opening;
• a first sealing disc having:
• a first surface providing sealing contact with the first flange;
• a second surface facing opposite the first surface;
• and
• an opening extending between the first surface and the second surface and having a cross-sectional area that is less than the first cross-sectional area;
• and
• a second sealing disc having:
• a first surface providing sealing contact with the second flange;
• a second surface facing opposite the first surface of the second sealing disc;
• and
• an opening extending between the first surface of the second sealing disc and the second surface of the second sealing disc and having a cross-sectional area that is less than the second cross-sectional area.

An apparatus comprising:

• a first housing containing a first pumping unit;
• a second housing containing a second pumping unit;
• a first flange extending from the first housing;
• a second flange extending from the second housing and secured to the first flange;
• a first conductor port and a second conductor port extending from the first housing;
• a third conductor port and a fourth conductor port extending from the second housing;
• and
• a conductor extending from the second conductor port to the third conductor port.