Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-09-14
2001-01-16
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C417S356000, C417S357000
Reexamination Certificate
active
06175173
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a centrifugal pump and, more particularly, to a pump which can be built into a pipe system and which fully contains the electric motor between the pump intake and discharge fittings.
BACKGROUND OF THE INVENTION
In-line pumps which comprise a pump housing through which a liquid is displaced by the rotation of an impeller within the housing by an electric motor fully contained therein and which have intake and outlet fittings at opposite ends of the pump housing are known. The motor is supported within the pump housing by a plurality of ribs and the liquid flows around the electric motor and thus serves as a coolant for the electric motor.
Such pumps are also known as tube pumps and the electric motors of such pumps are generally provided with electric controllers which are located externally of the pump housing. The electric controls thus require separate or additional housings and additional space which often may not be readily available. Where the electric circuitry generates heat, it may be necessary to provide separate cooling.
When it is desirable to use an in-line or tube pump of this type in a motor vehicle, these factors may be of considerable significance and may militate against use of a tube pump.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to provide a structurally simple, economical and easily handled and used centrifugal pump which has small external dimensions, light weight and efficient cooling of all parts associated with the pump including the electronic control circuitry.
Another object of the invention is to provide an in-line or tube pump which eliminates the drawbacks outlined above.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter are attained, in accordance with the invention, in a centrifugal pump which comprises:
an elongated tubular pump housing formed with an intake fitting at one axial end and a discharge fitting at an opposite axial end;
a pump impeller rotatable in the housing about an axis thereof for drawing liquid in through the intake fitting, passing the liquid axially through the housing and discharging the liquid through the discharge fitting;
an axially elongated electric motor wholly received in the housing between the intake fitting and the discharge fitting and flushed around by the liquid flowing between the intake fitting and the discharge fitting, the motor having a rotor rotatable about the axis and operatively connected to the impeller, a stator surrounding the rotor and provided with at least one winding, and a motor casing receiving the stator and spaced inwardly of the housing, whereby the liquid passes between the casing and the housing;
an electronic control unit for controlling the motor, wholly received in the housing and flushed around by the liquid; and
a plurality of angularly spaced support ribs between the housing and the casing for supporting the casing in the housing.
More particularly, the centrifugal pump of the invention contains an electric motor which is disposed entirely within the pump housing which is of the in-line type having axial inlet and discharge fittings at opposite ends thereof and in which the electric motor is supported within the pump housing at a spacing from the inner wall thereof by the support ribs. With the system of the invention, the electric control unit itself is in the form of a disk which closes the motor casing and is completely within the pump housing so that the liquid displaced by the pump flushes past that control unit.
With the system of the invention, a separate housing externally of the pump housing for the control unit is eliminated, the pump has small dimensions overall, is of light weight and has effective cooling both of the motor and of the control unit. Additional systems for cooling the electric circuitry are avoided.
The electric motor is preferably an electrically commutated brush-free direct current motor although it can also be configured as an alternating current motor in which the electric control circuitry can, for example, include a converter. The electric control circuitry can include a circuit board with a microprocessor controller, power transistors and the like.
It has been found to be especially advantageous to provide the electric control unit as a plug for an open end of the motor casing at the side thereof opposite the impeller. A single seal may be provided between the electronic control unit and the casing and can serve as the only seal for the latter. This eliminates the need for multiple seals and separate casing covers, thereby affording a further saving with respect to size and weight.
Advantageously, the motor is a so-called canned motor in which the motor can lining the inside of the stator and surrounding the rotor can be in one piece with the casing.
The cable for connection to the electric control unit can extend into the latter through one of the holding ribs and a plug connection can be provided for the conductors in a fitting on the pump housing. The conductors extending to the electric control unit are thus appropriately protected.
The in-line centrifugal pump of the invention, because of its narrow configuration, can be used highly effectively as a coolant pump for the internal combustion engine of a motor vehicle and hence in the motor vehicle coolant system.
It has long been known that the coolant in the circulation of a water cooled internal combustion engine can be circulated by a pump. In general, that pump is driven by a belt drive from the crank shaft of the internal combustion engine itself. More recently, however, it has been found to be advantageous to drive the water pump by a separate electric motor to be able to better control and regulate the cooling effectiveness.
In this case, the electric motor constitutes a component which must be accommodated in the engine compartment of the motor vehicle. In modern automotive vehicles, space is either not available in the engine compartment or is available so limitedly as to cause problems for the additional electric motor.
In addition, the high temperatures in the engine compartment make the cooling of the electronic circuitry of the electric motor especially important.
The invention accommodates the electric control circuitry directly within the housing of an in-line pump so that the pump itself is merely an extension of the piping of the coolant circulation. The pump is thus accommodated in a space-saving manner and, because the electronic controlled circuitry is located within the pump housing, cooling of the circuitry is simplified. The pump may also be accommodated within a container of the coolant circulation system, for example, a surge container or reservoir.
According to another feature of the invention, the noise generated by the pump is damped by the circulation of the liquid through the pump. It has been found to be especially advantageous to form the pump housing as a part of the piping for the circulation system so that the pump with the electronic motor and the electronic controlled unit are all completely received within the piping of the coolant circulation. The piping in the region of the pump will only have an increase in the pipe diameter. Special space for the pump and its electric controlled unit is not required.
When the pump is located in a surge vessel of the cooling circulation, that vessel may be dimensioned sufficiently so that the pump and its motor are fully contained within that container. This insures an especially effective cooling of the pump electronics.
It is also advantageous to mount the pump releasably in the surge container, i.e. so that it can be easily removed and inserted. This facilitates mounting and dismounting, e.g. for maintenance.
REFERENCES:
patent: 1787562 (1931-01-01), Barlow
patent: 2506827 (1950-05-01), Goodner
patent: 2520880 (1950-08-01), Harlamoff
patent: 2968249 (1961-01-01), Caine et al.
patent: 3211935 (1965-10-01), Sones
patent: 3294025 (1966-12-01), Niemeyer et al.
patent: 3826595 (197
Genster Albert
Kech Hansj{umlaut over (u)}rgen
Stephan Waldemar
Dubno Herbert
Ramirez Nestor
Waks Joseph
Wilo GmbH
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