WO2002074153A1

WO2002074153A1 - Device for measured dispensing of detergent in the washing water supply line of a dishwasher

Info

Publication number: WO2002074153A1
Application number: PCT/IB2002/000467
Authority: WO
Inventors: Erminio Dall'oglio
Original assignee: Wamasch Ag
Priority date: 2001-03-21
Filing date: 2002-02-15
Publication date: 2002-09-26

Abstract

A description is given of a device (1) for the measured dispensing of detergent and for the admission of washing water, timed by means of a timer, in a dishwater whose operation is exclusively hydraulic, comprising a measuring dispenser (2) with a membrane (3) for drawing in the detergent, the membrane in this equipment being operated by the pressure exerted on it by the washing water passing through a portion of the inlet tube (4) which the said membrane (3) faces. In the device (1) in question, downstream of the said portion of the inlet tube (4), there is formed a constriction of the cross section (5) capable of generating a predetermined hydraulic pressure upstream of it, and therefore in the said portion of the inlet tube (4), this pressure action on the surface of the aforesaid membrane (3), and the detergent drawn in by the measuring dispenser (2) being introduced by this device into the said constriction of the cross section (5) or into its proximity.

Description

DEVICE FOR MEASURED DISPENSING OF DETERGENT IN THE WASHING WATER SUPPLY LINE OF

A DISHWASHER

The present invention relates to the field of

5 dishwashers whose operation is exclusively hydraulic, in other words those in which no electrically powered elements of any kind or with any function are installed.

Examples of a dishwasher as described above are

10 illustrated in Swiss Patent Application 575/97.

These machines comprise, among other elements, a set of components designed to time the admission of the washing water and to draw in and measure the detergent which is mixed with this water; the present invention

15 relates in particular to a device which performs the aforesaid functions. A device of this kind has been described in Swiss Patent Application 2912/97 and in Italian Patent Application 1.298.877 in the name of the present applicant.

20 The inventor of the device to which the present patent application relates has found that certain problems arise in the operation of dishwashers using the aforesaid device according to the prior art.

Firstly, the membrane device for the measured

25 dispensing of the detergent, fitted in a portion of the washing water inlet tube, can operate correctly only if the pressure of the water mains is greater than approximately one bar (10⁵ Pa/m²), and this pressure is not always available, especially when a hydraulically

30 operated dishwasher is installed in peripheral areas remote from the main piping of a water supply line.

Secondly, the flow speed of the water in the said portion of the inlet tube is sometimes insufficient for correct and complete mixing of the detergent which is

35 fed into this portion.

Thirdly, in areas where the water is relatively hard, deposits and concretions of carbonates develop, causing problems which are familiar to those skilled in the art, and these problems cannot be efficiently overcome by fitting magnets on this portion of the inlet duct, since the flow speed of the water through it, and therefore also through the magnetic fields generated by the said magnets, is relatively too high, and the water treatment period is therefore too short.

In order to eliminate all the problems listed above, the inventor has developed a device for the measured dispensing of the detergent and for admitting the washing water, in which, by making appropriate use of different areas of the said portion of inlet tube with sections which are constricted and enlarged with respect to the section of the delivery tube from which the water is taken, the membrane of the measuring dispenser can be operated even at pressures of approximately 0.5 bar (0.5 x 10⁵ kPa/m²), and the detergent can be injected in an area where the water flows at high speed, thus promoting correct and complete mixing.

Additionally, in the area where there is a greater static pressure of the washing water for operating the said membrane, and consequently the flow speed of the water is reduced, the desired decalcification effects can be achieved by the fitting of the aforementioned magnets, suitably positioned and orientated. The object of the present invention is therefore to provide a device for the measured dispensing of detergent and for the admission of the washing water as described in the precharacterizing clause of the attached Claim 1, characterized by what is disclosed in the characterizing part of the said claim.

A simplified description of one of the various possible embodiments for a device according to the invention will now be provided.

In the course of the said description, reference will also be made to the attached drawings, which show: in Fig. 1, a partial exploded perspective view of the said embodiment of a device according to the invention; in Fig. 2, a complete side view of the device of Fig. 1.

With reference to Figures 1 and 2, these show how, in a hydraulically operated dishwasher (not shown), the washing water, whose flow is regulated by a timer (10, Fig. 2) designed for a plurality of programmes and timed pauses, runs, in the device 1 according to the invention, through a portion of inlet tube 4 having a longitudinal axis R-R, in the direction indicated by the arrows M. Along this path, the said portion of inlet tube 4 has a chamber 8 of increased cross section in the area facing the elastic membrane 3 of a measuring dispenser 2 (shown more fully in Fig. 2), which, by following the alternating motion (arrow D) of a guide rod 14 with a return spring 9, draws the detergent by known means from a reservoir 12 (Fig. 2) as a result of the action exerted by the washing water on the said membrane 3.

Immediately downstream of the said chamber 8, the portion of inlet pipe 4 has a marked constriction 5.

The flow speed of the water through the device therefore varies from a minimum value in the said chamber 8 of increased cross section to a maximum value in the constriction 5, the said values being respectively smaller than and greater than the flow speed of the water in the supply pipe of the water mains to which the device 1 is connected.

By means of a suitable circuit, of which only the terminal part, provided with a one-way valve 13, is shown in Fig. 1, the detergent drawn by the membrane 3 from the measuring dispenser 2 is introduced into the said portion of the inlet tube 4 at the position of the said constriction 5 (in this case the said terminal part is represented in continuous lines and indicated by the number 11), or immediately downstream of it (in this case the said terminal part is represented in broken lines and indicated by the number 11').

A plurality of magnets 6n with their polarity orientated towards the longitudinal axis of the said portion 4 are fitted in the said compartment 8 where the flow speed of the water is lower, on the parts 4p of the said portion of the inlet tube 4v. In the example illustrated, these magnets 6n are arranged and orientated in such a way as to face each other, forming a pair 7.

By this simple arrangement of the parts, based on a detailed study of the hydraulic and fluid dynamic phenomena, the inventor has achieved all the objectives which he had identified, namely to be able to operate the said membrane 3 in a satisfactory way even with mains pressures of approximately 0.5 bar (0.5xl0⁵ kPa/m²), to obtain reliable and rapid mixing of the detergent introduced at the position of the described constriction 5, and to be able to use the action of the said magnets 6n to decalcify the water, since they act on the water for a sufficiently long interval of time.

Clearly, the component parts of a device according to the invention can also be designed and arranged in ways that are different from those described and illustrated herein, while remaining within the scope of the teachings contained in the attached claims.

Claims

1. Device (1) for the measured dispensing of detergent and for the admission of washing water, timed by means of a timer, in a dishwasher whose operation is exclusively hydraulic, comprising a measuring dispenser (2) with a membrane (3) for drawing in the detergent, the membrane in this equipment being operated by the pressure exerted on it by the washing water passing through a portion of the inlet tube (4) which the said membrane (3) faces, characterized in that, downstream of the said portion of the inlet tube (4), there is formed a constriction of the cross section (5) capable of generating a predetermined hydraulic pressure upstream of it, and therefore in the said portion of the inlet tube (4), this pressure acting on the surface of the aforesaid membrane (3), and the detergent drawn in by the measuring dispenser (2) being introduced by this device into the said constriction of the cross section (5) or into its proximity.

2. Device according to Claim 1, in which the said portion of inlet tube (4), in the area in which the said membrane (3) faces it, has a chamber (8) of increased cross section and of a shape complementary to the profile of the said membrane (3).

3. Device according to either of Claims 1 and 2, in which a plurality of magnets (6n) with their polarity orientated towards the longitudinal axis (R-R) of the said portion of the inlet tube (4) are fitted on the walls (4p) of the said portion of the inlet tube (4).

4. Device according to Claim 3, in which the said magnets (6n) are arranged in such a way as to form one or more pairs (7) of magnets facing each other, between which the said chamber (8) of the portion of the inlet tube (4) is interposed.