New pump concept based on a sphere has the highest displacement-to-size ratio of any positive displacement pump.

It's a pretty safe bet that you have not seen anything like the Weatherbee Wedge Pump. Once you've seen it - and the out-of-the-box thinking that went into the design - it's also a pretty safe bet that the source will surprise you.
The Wedge Pump is not the product of a big company's massive research and development effort. Glenn and Paul Weatherbee, two brothers who operate a small oilfield production company in Abilene, Texas, developed the pump's design in their spare time over the past 15 years. Their original intent was to solve compressor problems in low-deliverability gas production operations. They think the design is revolutionary. "We believe it will do for the pumping industry what the microchip has done for electronics," said Paul Weatherbee.
The pump design is based on a sphere, which the developers state is the most efficient geometrical shape in the world. The spherical shape has significant advantages for pump applications. It has no corners or "dead" spaces, it is all swept volume and almost all of the internal volume of the sphere is displaced with each revolution. It also scales differently. Doubling the size of a conventional pump doubles the volume pumped. Doubling the size of the spherical pump increases the volume pumped eight times. In essence, doubling the Wedge Pump size cubes the volume displaced.
One prototype the developers are testing for oilfield use is an 81/2-in. model that displaces about a gallon, is about the size of a basketball and weighs about 75 lb. The developers claim that this model will do the work of a piston compressor weighing roughly 600 lb.
According to the developers, although the concept is simple, the design can be difficult to grasp, even for engineers viewing detailed drawings. Because of this difficulty, they had a model built (see nearby photo) that helps in visualization. To most observers, the model clearly demonstrates the pump's function, and the developers claim that one observer, upon viewing the model, called it the "most elegantly simple device he had ever seen."
How the Wedge Pump works
The pump is a four-chamber, four-port device with two vanes. A primary vane is rigidly attached to the pump's input/output shaft, and a secondary vane is hinged to the primary vane. The primary and secondary vanes rotate within a spherical housing, with the secondary vanes reciprocating between the open and closed positions. The primary and secondary vanes define the four chambers within the housing that communicate with the two inlet and two outlet ports on the pump.
During operation, power transmitted to the input/output shaft turns the primary vane. The distinguishing characteristic of this system is that the secondary vane reciprocates relative to the primary vane, so as the primary vane rotates with the input/output shaft, the secondary vane moves with respect to it.
Reciprocation of the secondary vane occurs as it rotates about two separate axes. One of these axes is the hinge axis. The other axis lies perpendicular to the hinge axis, in a plane at an angle relative to the centerline of the pump's input/output shaft.
Rotation of the secondary vane about these two axes causes the reciprocating motion. Reciprocation does not occur as a conventional back-and-forth movement. Instead, it is the result of a compound rotation about the two separate axes.
Key to the movement of the secondary vane is a center ball stationary shaft, with a carrier ring attached to the secondary vane. Together, these components provide a pinned-axis function, guiding the vane's movement and constraining it to remain in a "secondary plane."
Because of the combined motion of the primary and secondary vanes, the pump has two intake strokes and two exhaust strokes for every 180° of shaft rotation. For one 360° rotation, it has four intake and four exhaust strokes.
The pump has a unique capacity control mechanism. The adjustable stationary shaft, about which the secondary vane rotates, allows the degree of communication to be varied between the inlet and outlet ports in the chambers formed by the primary and secondary vanes. In this way, the flow rate or capacity of the pump can be changed. The capacity control mechanism can also reverse the direction of flow, without changing the rotational direction of the input/output shaft.
The capacity control mechanism allows the flow rate of the pump to be varied without changing the rotation rate of the input/output shaft (this is the only way to control flow rate with conventional pumps). Capacity control is useful for a variety of applications. In gas wells, for example, the pump uses only the energy necessary to compress the amount of gas the well is actually producing. One pump size is appropriate for a range of flow requirements. Capacity control is particularly beneficial in applications where compression requirements fluctuate or where volume can only be estimated and may vary drastically over time, as in gas well compression.
Unusual features
The Wedge Pump has other interesting features unique to its design. It functions equally well rotating clockwise or counterclockwise. The pump can be mounted in any position without affecting operation. It is a ported device that requires no valves. The direction of flow can be reversed without disconnecting the pump or changing rotational direction of the input/output shaft. The pump is a dual function device. It can perform as a hydraulic or pneumatic motor as well as a pump or compressor. The developers also state that it will handle high BTU gas.
Cardiovascular connection
Through what the developers describe as "a series of events," the Wedge Pump caught the attention of Dr. John Watson, then head of the National Institutes of Health. This may seem odd, given the divergent requirements of medicine and the oil field, but it turns out that the Wedge Pump and the human heart have remarkable similarities. They both: 1) have four chambers, 2) have two pumps (right and left side), 3) pulsate, 4) pump from both sides at the same time, 5) pump more from one side than the other, 6) have a different pressure on each side, and 7) pump similar volumes, with the wedge pump scaled to about half the size of an adult human heart.
The design compares favorably to existing artificial heart technologies. The Texas Heart Institute and other interested parties are working with the developers to secure funding to test the pump. According to the developers, the physicians see promise not only in the cardiovascular field but also in other medical applications.
Commercial application
Prototype field testing of the Wedge Pump is currently under way. In addition to the 81/2-in. model, three other sizes are under development: a 2-in. sphere displacing 3.17 cu in., a 4-in. sphere displacing 25 cu in. and a 5-in. sphere displacing 50 cu in. The developers see a wide range of oilfield applications for the pump. They are confident that its commercialization is inevitable but are not yet committing to a timetable. They say that several large companies are interested in its development. As for its cardiovascular application, the Wedge Pump won't be compressing gas - it will be saving lives.