Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
1998-08-14
2001-01-09
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Electric or magnetic motor
C417S420000
Reexamination Certificate
active
06171078
ABSTRACT:
The invention relates to a centrifugal pump for delivering a fluid and in particular to a centrifugal pump for delivering blood, especially a centrifugal pump in which the impeller is magnetically mounted and driven by a rotating field.
WO-A-96/31934 teaches a rotary pump in which the impeller is mounted to float inside the pump housing, supported by magnetic forces, and is driven by a rotating field created by a stator located outside the pump housing. Pumps of this kind are especially advantageous for applications in which the fluid to be delivered must not be contaminated, for example for delivering biological fluids such as blood or highly purified fluids such as super-clean water. In addition, rotary pumps of this kind are suitable for delivering aggressive fluids which would destroy mechanical bearings in a short time.
In designing such rotary pumps as centrifugal pumps, the problem arises that the end turns of the stator and the outlet of the pump housing block the space. To solve this problem, a pump with a so-called “temple” motor has been proposed in WO-A-96/31934 (see
FIG. 12
for example) in which the coil cores of the stator each have the shape of an “L” with the long leg in each case running parallel to the rotational axis, while the short leg is directed radially inward toward the rotational axis. The stator, designed as a bearing and drive stator, has two windings, namely the drive winding and the control winding, made in the form of discrete coils and wound around the long legs of the L-shaped coil cores. A temple motor of this kind does not require end turns so that the outlet of the pump housing can be located at the impeller without blocking the space. This design in the form of a temple motor is however subject to the limitation that it has a relatively large space requirement and is relatively expensive.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a centrifugal pump with a very compact design and with a high output. The centrifugal pump is intended to be as inexpensive as possible and in particular must permit a design in which the impeller is magnetically mounted and can be driven by an electromagnetic rotating field. In particular, a goal of the invention is a centrifugal pump that is as compact and efficient as possible and can be operated using the principle of the bearingless motor.
The invention will now be described in greater detail with reference to embodiments and to the drawing. In the drawings, which are not to scale, identical parts or parts with equivalent functions have been given the same reference numbers, the following are shown.
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patent: 5928131 (1999-07-01), Prem
patent: 5938412 (1999-08-01), Izraelev
Fastovsky Leonid
Sulzer Electronics AG
Townsend and Townsend / and Crew LLP
Walberg Teresa
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