High speed electrically driven axial-flow pump and boat driven t

Details High speed electrically driven axial-flow pump and boat driven t High speed electrically driven axial-flow pump and boat driven t

1994-10-19

1996-01-16

Bertsch, Richard A.

Pumps

Condition responsive control of pump drive motor

By control of electric or magnetic drive motor

417 42, 417 441, 417355, 417356, 415 91, F04B 4906

Patent

active

054842662

DESCRIPTION:

BRIEF SUMMARY
The instant invention concerns a high speed electrically driven axial-flow pump consisting of a stator in a sealed casing, a rotor located inside the stator casing which rotates on an axis, said rotor comprising a tubular central portion that forms one exterior wall of the central axial channel through which fluid passes continuously and which supports the blades in said channel, and electromagnetic drive means which have magnets disposed along said tubular central portion of the rotor, said magnets cooperating with the electrical coils in the stator located inside the sealed casing.
The invention further concerns a boat driven by such a pump.
An electrically driven pump is usually separate from the motor and connected to it by a rotating shaft. Generally the two devices are coaxial in order to eliminate discharges caused when gears or other transmission devices mesh. However, this arrangement has specific disadvantages in the case of an axial-flow pump. The machines may each be disposed in the extension of the other and separated by an elbow in the fluid inlet or outlet channel, but in this case the shaft obstructs fluid flow in the elbow. Alternatively, the electric motor could be located in a bulbous area located in the center of the fluid channel, with one end of the bulb supporting a large helix. In this situation the fluid flow path would also deviate axially to a significant extent in order to skirt the bulb. All these deviations cause energy loss, increase bulk and make it difficult to augment fluid speed. Furthermore, the shaft and the pump wheel are less stable at high speeds; therefore, the shaft supports need to be reinforced and consequently, the liquid loses even more power.
To avoid the problems described above, one known solution uses a rotor that is common to the pump and the electric motor with a central tubular portion serving as the pump wheel and a peripheral portion comprising the rotor elements of the electric motor. For example, an axial pump of the type described in the preamble is shown in FIGS. 5-13 of European Patent No. 0 169 682. It is driven by a squirrel cage type motor. The result is a rotor that is relatively long in relation to its diameter and which, in addition, is not capable of rotating at very high speed. Consequently, the axial channel and the pump blades must also be fairly long to transmit enough power to the fluid. In the embodiment described, the blades are formed by a spiral axial body placed in the central channel; they have an elongate central element which poses the problem of reducing the fluid passage section. U.S. Pat. No. 3,719,436 shows the same type of pump with an induction motor presenting similar problems. The pump blades are supported by the wall of the central channel, however, so that the center of the channel is free.
Publication No. WO 91/19 103 describes a miniature blood pumping device with a configuration essentially analogous to the embodiments described above, but with a generally stator-like central body which traverses the rotor axially so that the central channel is annular in shape, causing considerable loss of power. Here again the rotor is relatively long and speed is intentionally limited (16,500 rotations per minute) to prevent damage to the blood cells.
The object of the present invention is to perfect such a combined axial-flow pump and electric motor with a common rotor and with the hydraulic and electrical elements arranged concentrically, allowing very high rotation speeds and resulting in a highly powerful, compact pump. A specific object is for the pumping fluid to flow in as straight a line as possible with few obstructions.
A first characteristic of the invention concerns a pump of the type described in the preamble, characterized in that the length of the rotor is smaller than its outer diameter.
Thus, since the poles of the electrical device are relatively far away from the axis of rotation, the magnetic attraction and repulsion forces acting thereupon are very effective and produce a high degree of motor coupling. The b

REFERENCES:
patent: 1347732 (1920-07-01), Cooper
patent: 1714330 (1929-05-01), Tucker
patent: 2113213 (1938-05-01), Leonard
patent: 2274274 (1942-02-01), Pezzillo
patent: 2697986 (1954-12-01), Meagher
patent: 3119342 (1964-01-01), White
patent: 3143972 (1964-08-01), Smith et al.
patent: 3273506 (1966-09-01), Jamieson
patent: 3719436 (1973-03-01), McFarlin

Affiliated with

Also associated with

Rating

High speed electrically driven axial-flow pump and boat driven t does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with High speed electrically driven axial-flow pump and boat driven t, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High speed electrically driven axial-flow pump and boat driven t will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-305330