Washing machine

Abstract: The present invention relates to a washing machine comprising a washing chamber (1) with a first hole (2) on its lower side connected to a drain pump (3) through a pipe (9), and with a second hole (4) connected to said drain pump (3) through a pipe (8), and inside said washing chamber (1) a drum (7) revolving around a horizontal axis; the main characteristic of the machine consists in that during washing the configuration of said revolving drum (7) produces an effect similar to that of a pump propeller, that said second hole (4) is located preferably at a level not over the one where is located said first hole (2), and that the washing chamber (1) is configured in such a way to have the pipe (8) connecting said second hole (4) to the drain pump (3) arranged tangentially to the drum rotation sense, so that when the drum (7) rotates it causes the washing fluid to enter said second hole (4) and said tangential pipe (8) with enough force to cause circulation of said fluid, which flows back into the washing chamber (1) through said first hole (2).

Description: The present invention relates to a washing machine comprising a washing chamber with a first hole on its lower side connected to a drain pump through a pipe, and with a second hole connected to said drain pump through a pipe, and inside said washing chamber a drum revolving around a horizontal axis. As known, one problem washing machine manufacturers have to solve is to reduce the waste of soap-powder, as it used to occur in the machines till a few years ago due to the intake method of said powder. Soap-powder is taken in from the so-called "dispenser" by means of a water jet conveying the powder into the washing chamber within a time ranging from 90 to 120 secs. Obviously, the major part of the soap-powder is flushed in during the initial seconds of intake, so that initially soap-powder concentration is very high. Said soap-powder, with is not yet dissolved, deposits mixed with water on the lowest part of the washing chamber where there is the pipe connecting to the discharge pump, which for hydraulic reasons should be the lowest spot of the system. It is obvious that the pump screw and connected pipes fill up with said water soap-powder mix, which will remain inactive during both pre-wash and wash cycles, as it is not in contact with the laundry inside the drum. During the last few years several systems have been suggested to obviate to such an inconvenience causing a waste of soap-powder whereby both the washing costs and environmental pollution increase. As an example, German Patent Application nr. 26 55 556 describes a washing machine where the washing chamber has a further hole connected to the discharge pump in addition to the standard outlet hole. Such an additional hole is located above the water level normally reached by the water in the washing chamber; during washing cycle the alternate drum rotation causes a water motion and a small part of water falls into such an additional hole acquiring enough speed by gravity so as to flow back up to the washing chamber through the standard outlet hole. Through such a circulation it is possible to reduce the waste of soap-powder, as a part of the powder initially accumulated in the discharge system is recirculated. Italian Patent nr. 1 083 306 describes a washing machine with a soap-powder recovery system similar to the one described in the German application; however, it is provided with a second hole at a lower level than normally reached by the water in the washing chamber; according to the patent application circulation is obtained anyway, since due to the drum motion some differences of hydraulic pressure occur. Said system are not very efficient though ensuring a partial recovery of the soap-powder being wasted. Purpose of the present invention is to indicate a washing machine with a system as simple as the ones already known but performing to a more efficient extent for the recovery of the greatest part of soap-powder accumulated inside the discharge pipe system during intake. To achieve said purpose it is the aim of the present invention to realize a washing machine comprising a washing chamber with a first hole on its lower side connected to a drain pump through a pipe, and with a second hole connected to said drain pump through a pipe, and inside said washing chamber a drum revolving around a horizontal axis, characterized in that during washing the configuration of said revolving drum produces an effect that is similar to that of a pump propeller; that such second hole is located preferably at a level not over the one where is located said first hole, and that the washing chamber is configurated in such a way to have the pipe connecting said second hole to the drain pump arranged tangentially to the drum rotation sense, so that when the drum rotates it causes the washing fluid to enter said second hole and said tangential pipe with enough force to cause an efficient circulation of said fluid, which flows back into the washing chamber through said first hole. Other purposes and advantages of the present invention are clearly detailed in the following description and annexed drawings supplied by way of explanatory but not limiting example, where: the figure is a sectional view of the washing chamber and discharge piping of a washing machine according to the present invention. In said figure describing the washing chamber and outlet hoses of a washing machine according to the present invention, ref. nr. 1 refers to the washing chamber, which may be of enamelled sheet, stainless steel or plastic material; washing chamber 1 shows number 2 a first hole connected to the drain pump 3 by a pipe, namely to an upright pipe-socket of said pump. Washing chamber 1 also shows a second hole referred under number 4, tangential to the washing chamber but slightly lower than the first hole 2. The second hole 4 is connected to the same pump 3 through a pipe 8. Pump 3 shows a third outlet pipe-socket 6. Washing chamber 1 contains the revolving drum 7, where the laundry to be washed is introduced; said drum 7 has three V-shaped recesses 5, whose vertexes are directed to the drum centre. The special drum configuration as well as that of the washing chamber cooperate to let the drum acting as a real and true pump propeller whose screw, in the specific instance, is represented by the washing chamber. During pre-wash and/or washing the drum rotates both clockwise and anti-clockwise alternatively at a speed rate of about 60 rev/min. With the pipe connecting the washing chamber to the pump arranged perfectly tangential to a washing chamber wall the condition is obtained where the drum exerts a pressure inside the pipe itself by rotating tangentially to the piping. Thus, an efficient circulation from the washing chamber to the pump and back again to the washing chamber is ensured, so that the soap-powder that otherwise would remain unused is returned to the washing chamber. Due to the washing and pre-wash times lasting long enough, it is possible for the soap-powder to dissolve and be recovered. The characteristics of the above washing machine are clearly shown in the above description and annexed drawings. Likewise the above description is also clearly showing the advantages of the washing machine according to the present invention; as a matter of fact, both the synergy obtained through the special drum configuration and arrangement of the second hole as well as the tangential location of the relevant piping allow an efficient circulation, without any cost increase, for the recovery of most part of the soap-powder accumulated at the bottom of the machine during intake stage. It is obvious that for the man skilled in the art many other changes are possible to the washing machine described by way of example but without departing from the scope of the innovating criteria inherent of the present invention.

Claims: Washing machine, comprising a washing chamber with a first hole on its lower side connected to a drain pump through a pipe, and with a second hole connected to said drain pump through a pipe, and inside said washing chamber a drum revolving around a horizontal axis, characterized in that during washing the configuration of said revolving drum (7) produces an effect similar to that of a pump propeller, that said second hole (4) is located preferably at a level not over the one where is located said first hole (2), and that the washing chamber is configurated in such a way to have the pipe (8), connecting said second hole to the drain pump, arranged tangentially to the drum (7) rotation sense, so that when the drum (7) rotates it causes the washing fluid to enter said second hole (4) and said tangential pipe (8) with enough force to cause an efficient circulation of said fluid, which flows back into the washing chamber (1) through said first hole (2). Washing machine according to claim 1, characterized in that the wall of said revolving drum (7) has some V-shaped recesses (5) on its peripheral side, whose vertexes are directed to the drum centre. Washing machine according to claim 1, characterized in that the pipe connecting said first hole (2) to said drain pump (3) is connected to said pump (3) through a pipe-socket directed upwards. Washing machine according to claim 1, characterized in that during washing said revolving drum (7) is rotated in both directions alternatively, at a speed rate of about 60 rev/min.

Inventors: AGNES PIERANGELO, AGNES, PIERANGELO
Applicants: MERLONI ELETTRODOMESTICI SPA, MERLONI ELETTRODOMESTICI S.P.A.
Application year: 1990
Main classification: D06F39
IPC codes: D06F39