Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2002-07-16
2004-06-01
Yu, Justine R. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S423700, C415S056100
Reexamination Certificate
active
06743000
ABSTRACT:
TECHNICAL FIELD
The present invention relates to hydraulic pumps for dishwashers and washing machines, and more specifically to synchronous hydraulic pumps.
BACKGROUND OF THE INVENTION
Synchronous hydraulic pumps for dishwashers and washing machines are already known. Said pumps comprise a synchronous motor, an impeller coaxial to said synchronous motor and a hydraulic body, said impeller being housed in said hydraulic body. The hydraulic body has an inlet pipe and an outlet pipe, the incoming water being evacuated from the former to the latter pipe by means of the rotation of the impeller.
Pumps of this type usually have priming problems due to the air that builds up together with the water inside the hydraulic body. One solution so that the least possible amount of air collects inside the hydraulic body is to reduce the space inside said hydraulic body (and therefore the place where air could be housed) to a minimum. This is often not feasible due to the hydraulic or dimensional requirements of the housing where the pump is installed.
Another solution is to force out the air that collects inside the hydraulic pump adding a third pipe to the hydraulic body at the top, via which the air is evacuated to the exterior, being forced out to the washing chamber. The existence of said third pipe for air recirculation nevertheless brings about a loss of output flow, a loss that will be greater the larger the diameter of the third pipe is. Therefore, so that the flow loss may be as little as possible, small diameters are used in relation to the diameter of the outlet pipe. This means that, during the lifetime of the appliance, said third pipe becomes blocked and requires the intervention of the technical service. In addition, dirty water recirculates through said third pipe to the washing chamber, thereby reducing the washing quality of the appliance.
On the other hand, it is important to increase the output flow of the pump as much as possible. One way to do so is to increase the impeller's dimensions, but this entails higher power consumption along with noisier pump operation.
DESCRIPTION OF THE INVENTION
The main object of the invention is to provide a synchronous hydraulic pump that overcomes the priming problem without the need to incorporate a third pipe for air recirculation.
The hydraulic pump of the invention comprises a synchronous motor, an impeller coaxial to said synchronous motor and a hydraulic body, said impeller being housed in said hydraulic body and the hydraulic body having an inlet pipe and an outlet pipe. Said pump also comprises at least one piece adjacent to the impeller which has a projection pointing towards the outlet pipe, in such a way that said projection acts as a guider directing the flow circulating inside the hydraulic body towards said outlet pipe.
In this way, a good proportion of the mass of water is prevented from circulating permanently “integral” with the impeller together with the accumulated air. Thus, the air that would otherwise build up inside the hydraulic body is forced out via the outlet pipe, along with the mass of water, so that the priming problem is resolved. Furthermore, besides overcoming the priming problem, directing the flow also increases output delivery considerably.
Therefore, the invention has the following advantages:
the priming problem is solved without the use of a third pipe for air recirculation, whereby the drawbacks stemming from the use of this third pipe are avoided, and
a considerable output flow is obtained without having to increase the dimensions of the impeller, whereby the increased power consumption that would be involved is avoided, and also the increased noise level entailed.
The piece that acts as a guider directs the flow towards the outlet pipe irrespective of the direction of rotation of the impeller.
REFERENCES:
patent: 984456 (1911-02-01), Trenary
patent: 1993268 (1935-03-01), Ferguson
patent: 2006590 (1935-07-01), Ferguson
patent: 3266428 (1966-08-01), Feith et al.
patent: 3656861 (1972-04-01), Zagar
patent: 4172695 (1979-10-01), Uesugi
patent: 4759690 (1988-07-01), Deschamps et al.
Mark's Standard Handbook for Mechanical Engineers, 10thEd., McGraw-Hill, Boston Mass., 1996; p. 15-40, column 2.
Fagor S. Coop.
Solak Timothy P.
The Kline Law Firm
Yu Justine R.
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