Rotary kinetic fluid motors or pumps – With means for re-entry of working fluid to blade set – Turbine regenerative pump
Patent
1994-12-19
1996-06-18
Look, Edward K.
Rotary kinetic fluid motors or pumps
With means for re-entry of working fluid to blade set
Turbine regenerative pump
415 551, F04D 500, F04D 2916
Patent
active
055271502
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to regenerative pumps and in particular to a type of pump that is suitable for use in supplying compressed air to an internal combustion engine, in which context it is commonly referred to as a regenerative blower.
SUMMARY AND OBJECT OF THE INVENTION
A regenerative pump basically comprises a rotating impeller with a plurality of radial blades located within a casing. The impeller draws a fluid such as air or other gas through an inlet port into the pump casing. Upon contact with an impeller blade the fluid is forced radially outward toward the wall of the casing and follows the wall radially inwardly until it is again drawn into contact with another blade and the process continues by centrifugal force. Because the impeller is designed with a plurality of radial blades such that fluid is compressed many times during its passage through the pump in that air forced radially outward by a blade is recompressed by a succeeding blade thus generating the effect of a multi-stage compressor, relatively high pressures can be generated at the outlet port.
The great advantage of such pumps is that by reliance on multiple passes through the blades rather than high speeds and many moving parts to develop pressure, component life is generally much longer. Indeed the life of such a pump is limited typically only by the life of the bearings which support the impeller shaft. In addition, as lubricants are not present within the housing, gas produced by the pump is much cleaner than that produced by some other types of compressor.
However, when used for applications which place a premium on reducing the size and weight of components, regenerative pumps, as presently designed, have a great disadvantage in that it is not possible to generate desired pressures without increasing the size of the pump to unacceptable levels. This is particularly so when the pump is used as a blower for internal combustion, such as automotive, engines.
One source of this problem is an inherent characteristic of the pump known as "carryover loss". Carryover loss is caused by loss of compressed fluid trapped between the blades when passing through a stripper portion which isolates the inlet port from the outlet port, the sealing being achieved by a close fit of the blades within the walls of the stripper portion. Such loss directly impacts on the compressive capacity of the pump by reducing the volume of fluid that passes through the pump at the required compression.
This problem is compounded by the actual design of the stripper portion. The stripper portion typically extends along a significant portion of the periphery of the blower casing and no compression can take place in this area because the walls defining the stripper are in sealing proximity with the impeller blades such that no air can pass through the blades to generate a compressive effect. In known blowers, the stripper portion, in combination with the inlet and outlet ports, embraces a significant proportion of the circumference of the impeller and, as such, a substantial proportion of the compressive capacity of the blower is unable to be utilized.
Therefore, there is a need, especially in the case of blowers for internal combustion engine, particularly automotive engine, applications to develop a pump that has as high a compressive capacity as possible for a given circumference.
With this object in view, the present invention provides a regenerative pump comprising a casing provided with an inlet port for admission of fluid to said pump, an impeller having a plurality of blades to generate, upon rotation, multistage compression of said admitted fluid and an outlet port for discharge of compressed fluid from the casing, the inlet port being isolated from the outlet port by a stripper portion, said blades having an inner edge and an outer edge with respect to the radial disposition of the blades, wherein said stripper portion and said blades are relatively configured such that said outer edge of each blade enters said stripper port
REFERENCES:
patent: 3545890 (1970-12-01), Hubbard et al.
patent: 3942906 (1976-03-01), Schonwald
patent: 4412781 (1983-11-01), Abe et al.
patent: 4749338 (1988-07-01), Galtz
patent: 4824322 (1989-04-01), Middleton
patent: 5143511 (1992-09-01), Verneau et al.
Lee Michael S.
Look Edward K.
Orbital Engine Company (Australia) Pty. Limited
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