GB2438409A

GB2438409A - Lattice pump and engine

Info

Publication number: GB2438409A
Application number: GB0610347A
Authority: GB
Inventors: David Hostettler Wain
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-05-25
Filing date: 2006-05-25
Publication date: 2007-11-28
Also published as: GB0610347D0

Abstract

The pump comprises a lattice, e.g. a square, of identical rotors, each 90 degrees out of phase with its neighbours and arranged to such that a rotor tip touches a flank of its neighbour to form fluid pockets between adjacent rotors. Each rotor is broadly lenicular or elliptical as if two quarter circle segments were arranged back-to-back. The rotors may be twisted along their length and the rate of twist may be varied. The working fluid may be a fuel and oxidiser which may be compressed, ignited and expanded to form an engine. Synchronising gears may be used but if the working fluid is sufficiently lubricating and the twist sufficiently great, the rotors may self synchronise with no external gears required. The rotors may be formed to a Z shape.

Description

LATTICE PUMP & ENGINE This invention relates to lattice pump.

Many types of pump are available -some are negative displacement and some are positive displacement. Negative displacement pumps rely on the weight of the fluid to work. Positive displacement pumps use a change in volume to work.

Examples of negative displacement pumps include propellers or centrifugal pumps.

Positive displacement pumps include those such as piston and diaphragm pumps.

Many positive displacement pumps comprise contra-rotating rotors. These mesh together so that the fluid is squeezed either along the rotor or in/out using valves.

The only positive displacement pump whereby the rotors co-rotate is one where the rotors comprise two (or three!) segments of a circle, "glued" together.

With circular segment rotors, the tip of one rotor is always in contact with the curved part of one of its neighbours. Thus the area enclosed by, say, four rotors arranged in a square, varies and hence can be used as a pump. Note that the curved part of the rotor is a circle because that is the trajectory of a neighbouring tip in a frame of reference rotating at the same rate.

The advantage of co-rotating lobes or rotors is that they can be arranged in a repeating lattice. This can be useful since the moment of inertia of many small rotors is less than that of large rotors, and the edge effects are minimised.

According to the present invention there is provided a lattice pump comprising circular segment rotors arranged in a repeating lattice such that each tip of the rotors is always in contact with the curved part one of its neighbours.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which:- Figure 1 shows a single quarter segment rotor.

Figure 2 shows a quarter segment pump with intermediate areas.

Figure 3 shows a quarter segment pump with maximum & minimum (zero) areas.

Figure 4 shows a single curved-Z propeller.

Referring to the drawing each lobe comprises two quarter circle (radius r) segments, "glued" together back-to-back. These are arranged in a square lattice (distance d apart) such that each lobe is rotated (in phase) by 90 degrees from its neighbours.

For completeness, the distance between the two tips of a rotor is (root 2).r and the distance between the axes (centre) of each rotor is d = r. That is, the distance between the rotors is the same as the radius of the circular segments. -.1-

Now with a lattice pump, the area enclosed by the rotors is made into a volume by introducing depth (all diagrams are only 2-D for simplicity). Thus as the rotors rotate, the volume (area x depth) enclosed varies, thus forming a simple positive displacement pump.

However, if we then twist the rotors in the Z-axis (into the page), the amount of fluid enclosed varies along the length of the rotors. As the rotors rotate, the fluid moves along the rotors in the direction of the Z-axis.

Of course, the rate of twist along the rotors can be varied, thus allowing the fluid to be compressed (or rarefied) too. In other words as the fluid moves along the Z-axis, the enclosed volume can be made to change, either compressing (fast twist) or rarefying (slow twist) the fluid.

The rate of rotation and twist is the same for every lobe. Each neighbour has a fixed rotation (or phase) relative to its neighbour. That is, with a quarter segment pump, each lobe differs in phase from its neighbours by 90 degrees.

In order to synchronise the rotors, external gearing can be used. However, it should be noted that provided the rotors have sufficient twist, and provided the fluid is sufficiently lubricating, the lobes will self synchronise. That is, with lubricating fluids, no external meshing gears are required since the lobes act as their own gears.

Note the since compression and/or rarefaction of the fluid can be made to occur along the length of the rotors, an engine becomes possible. Provided any ignitors (if required) remain within the bounds denoted by their circular segments, a fuel/oxidant mix can be ignited at some point along the length of the rotors.

Thus a fuel/oxidant mix can be compressed, ignited and then expanded along the rotors, forming a positive displacement turbine engine. As the fluid expands, the rotors rarefy the exhaust, thus powering the engine. The front of the engine compresses the fuel/air until ignition, and the back part of the engine converts the expansion of gas into mechanical work.

Note also, that provided the lobes remain within the bounds denoted by the circular segments, any intermediate shape is allowed. Of course, intermediate shapes may not provide positive displacement or self synchronisation. However, such shapes could be especially useful at the inlet or outlet, where a curved-Z propeller shape would provide a smoother transition for the fluid.

In fact, the curved-Z propeller is an especially interesting example, since the lobes still provide self synchronisation. If used without "filling" the lobes out to their bounding segments at some point along their length, the pump remains a negative displacement pump, relying on the inertia of the fluid for operation. A lattice of curved-Z propellers is thus possible too.

Claims

CLAIMS

1. A lattice pump comprising circular segment rotors arranged in a repeating lattice such that each tip of the rotors is always in contact with the curved part of one of its neighbours.

2. A lattice pump as claimed in claim 1 whereby the rotors have depth, thus enclosing volumes that vary as the rotors rotate.

3. A lattice pump as claimed in claims 1 & 2 whereby the rotors may be twisted along their length, such that the enclosed volumes move along their length as the rotors rotate.

4. A lattice pump as claimed in claims 1, 2 & 3 whereby the rate of twist may be varied along their length providing compression or rarefaction of the fluid.

5. A lattice pump as claimed in claims 1, 2 & 3 whereby if there is sufficient twist and the fluid is sufficiently lubricating, no external mesh gears are required.

6. A lattice pump as claimed in claims 1, 2 & 3 whereby the rate of twist may be varied along their length providing compression or rarefaction of the fluid.

7. A lattice pump as claimed in claims 1, 2, 3, 4 & 6 whereby if the fluid is fuel/oxidant, if may be compressed, ignited and then rarefied, forming a positive displacement turbine engine.

8. A lattice pump as claimed in claim 1 whereby the rotors can be any intermediate shape within the bounds of the circular segments.

9. A lattice pump as claimed in claims 1, 2, 3, 5 & 8 whereby the rotors may be formed into curved-Z propellers.