WO2009079319A1

WO2009079319A1 - Integrated feeding and liquid level detecting device for a tank, in particular a rinsing water boiler, and rinsing system and dishwasher featuring such a device

Info

Publication number: WO2009079319A1
Application number: PCT/US2008/086343
Authority: WO
Inventors: Gianluca Pardini
Original assignee: Premark Feg L.L.C.
Priority date: 2007-12-14
Filing date: 2008-12-11
Publication date: 2009-06-25
Also published as: ITTO20070901A1; EP2237714A1; EP2237714B1

Abstract

A device (1) insertable onto a feeding mouth (15) of a tank (7) and consisting of a hollow body (20) divided into three compartments (21,22,23) connected to one another by means of a base portion (24) of the body arranged in use downwards and from which the three compartments transversally and overhangingly extend upwards, wherein a first and a second compartments (21,22) are arranged adjacent and are provided, at the free ends thereof, the first with a hydraulic connection (26) to a rinsing water feeding pipe (12), and the second to a vent (27), and are both hydraulically connected by means of the base portion to a tube (30) for the connection to the feeding mouth, which tube is integrally obtained with the body and internally provided with a transverse wall (31) vertically oriented in use and which extends into the base portion to create two parallel and separate connecting pipes (32, 33) between the tank and the first (21) and second (22) compartments; a siphon bottleneck (36) in the base portion connects the third compartment (23) to the second one (22) and a pressure inlet (38) is carried by the free end of the third compartment.

Description

INTEGRATED FEEDING AND LIQUID LEVEL DETECTING DEVICE FOR A

TANK, IN PARTICULAR A RINSING WATER BOILER, AND RINSING SYSTEM

AND DISHWASHER FEATURING SUCH A DEVICE

TECHNICAL FIELD

The present invention relates to an integrated device for feeding a liquid in a tank and for detecting the level reached by such a liquid in the tank itself. In particular, the device according to the invention may be applied onto the inlet of a rinsing water heating boiler in a dishwashing machine for professional use, i.e. intended for users, such as bars, restaurants, public venues and not for a simple domestic use.

BACKGROUND ART

It is known that in order to obtain good rinsing performances, the pressure and temperature of the water need to always be as constant and close as possible to the value chosen during the step of designing.

In traditional systems (figure 1), the rinsing in an electric household appliance 2, in this case a dishwashing machine, occurs by exploiting the network pressure which pushes the existing water into the boiler B and, then, towards a washing chamber 3 of the electric household appliance 2; there is therefore a direct dependency between rinsing pressure and flow rate and network pressure. Furthermore, when rinsing, the boiler B is accessed by cold water which is mixed with hot water, so that the water temperature is kept high only for a short time; the whole process is thus conditioned by the network. The water flow in such a case is adjusted in a simple manner by means of a solenoid valve (not shown) which, when open, starts the rinsing.

In order to make the rinsing independent of the network, the so-called "CRP system" ("Constant Rinse Performance") has recently been adopted, in which the rinsing occurs at a constant pressure in virtue of an open boiler Bl and a pressure increasing pump P; furthermore, the temperature is kept constant because cold water for restoring the level is only introduced at the end of rinsing.

With reference to figure 3, the electric household appliance 2 in figure 2 is provided with a rinsing system R in which the network inlet is interrupted by means of an air gap by inserting a break tank C open to the atmosphere upstream of the boiler Bl; the water in the boiler Bl is taken to temperature and pushed into the washing chamber 3 by the pump P; when the rinsing cycle has ended, the boiler Bl is filled and heated again. As the circuit is open, the solenoid valve (not shown) alone is no longer sufficient to control the flow rate, and the level of water in the boiler Bl needs also to be controlled to prevent a possible overflowing; a manostat bell PR connected to an electronic manostat PM is used for this purpose.

Therefore, according to the solution described and illustrated in figure 3, the boiler Bl needs to be provided with four holes or outlets F1,F2,F3,F4 for the connection to the water feeding means C, to the pump P and to the bell PR, respectively; in particular, as the system is open, the hole or outlet F 1 allows to vent the air towards the tank or break tank C open to the atmosphere, while the hole or outlet F2 receives the network water no longer pressurized after the air gap by gravity; the plastic manostat bell PR connected to the hole F4 forms an air trap which allows to detect the level of water in the boiler B 1 by means of the manostat PM in an indirect manner.

Generally, the plastic manostat bell PR is positioned at the front part of the boiler Bl, both for problems of volume and for ease of maintenance. However the space available in the front of the electric household appliance 2 is limited by the presence of the resistors and by the temperature probe, whereby the dimensions of the bell PR need to be necessarily limited. These small dimensions cause an inaccurate level detection, because it is conditioned by the temperature variations which may increase or decrease the air volume entrapped in the bell PR with the possibility of switching the manostat PM at a different level from that desired.

According to EP-A- 1854393, the problem of improving the rinsing performance consistency without risking incorrect liquid level readings in the boiler, which on one hand may cause overflowing situations with consequent possible damages, or an insufficient rinsing, is solved by means of a complex, costly and cumbersome system, in which the rinsing water is fed into the washing chamber in an irregular manner.

DISCLOSURE OF INVENTION

It is thus the object of the present invention to provide an improved rinsing system for an electric household appliance, in particular for a dishwashing machine for professional use, which overcomes all the described drawbacks, in particular allowing to decrease the number of holes (and couplings) present on the boiler and, more in general, to provide a device for feeding a liquid into a tank and for detecting the level reached by such a liquid, usable in such a rinsing system, which is small, cost-effective, highly simple and reliable.

Finally, it is a further object of the invention to provide a dishwashing machine provided with such a rinsing device and system which, therefore, has high washing performances and reliability.

According to the invention, an integrated device for feeding a liquid in a tank and for detecting the level reached by such a liquid in the tank itself for an electric household appliance, in particular a dishwashing machine, is thus provided as defined in claim 1.

The invention further relates to a rinsing system, as defined in claim 10, and to an electric household appliance, as defined in claim 11.

In particular, the integrated device according to the invention consists in an internally hollow body divided into three compartments connected to one another to form corresponding vessels communicating by means of a base portion of the body intended in use to be arranged downward and from which the three compartments extend transversally and overhangingly so as to be vertically oriented in use, wherein a first and a second compartments are arranged immediately adjacent to each other and are provided, at their corresponding free ends, the first with a hydraulic connecting element to a liquid feeding pipe and the second to a vent, and are both hydraulically connected by means of the base portion to a tube fluid-tightly connectable in use to the feeding mouth of the tank, which tube is integrally obtained with the body and is internally provided with a transverse wall oriented parallelly to the direction of overhanging extension of the three compartments, and which extends into the base portion to create in use a first and second connecting pipes, reciprocally parallel and separate, to the tank for the first and second compartments, respectively.

The second compartment is hydraulically connected to the third compartment by means of a bottleneck in the base portion forming a siphon towards the second compartment; furthermore, the third compartment carries, at the free end thereof, a pressure inlet connectable in use to a manostat.

In this manner, a new integrated system for "loading" the rinsing water is made, which groups together what substantially becomes a manostat bell (consisting of the third compartment and of a part of the adjacent second compartment) and a fluid inlet device into the boiler by gravity only.

The body is preferably made as a plastic material component, obtained either by molding in one piece or by fluid-tightly joining two half shells. In either case, the presence of the wall in the boiler delivery tube allows to divide such a single tube into two separate pipes, a first pipe which feeds the water to the boiler and a second pipe which, by means of the vent of the second compartment, allows the water in the boiler to enter the air trap formed by the third compartment and, thus, to detect the level thereof.

Furthermore, the presence of the wall prevents the turbulence and the pressure of the inlet fluid (water) from influencing the air trap. Consequently, on one hand, by means of a single hole in the boiler, two functions are served (fluid entering and boiler level measurement) and, on the other hand, in virtue of the extreme compactness of the system, the manostat bell may be appropriately sized, thus avoiding possible measurement errors.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the invention will be apparent from the following description of a non-limitative embodiment thereof, provided only by way of mere example and with reference to the accompanying drawings, in which:

- figures from 1 to 3 diagrammatically show an electric household appliance and rising systems for the same, in this case for a dishwashing machine, made according to the prior art;

- figure 4 diagrammatically shows a rinsing system for the electric household appliance in figure 2 made according to the invention;

- figure 5 shows on enlarged scale a perspective view of an integrated device for feeding water and detecting its level made according to the invention and applicable to the rinsing system in figure 4; and

- figure 6 are an elevation side view with parts in section of the integrated device in figure 5 applied to a rinsing system as that shown in figure 4 of a dishwashing machine.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to figures from 4 to 6, numeral 2 indicates as a whole an electric household appliance, in particular a front loading dishwashing machine, comprising a washing chamber 3 delimited at its lower part by a tank 4 and at its front part by a pivoting access door 5, and a hot rinsing system 6 mounted, in this non-limitative case, by the side of the door 5 and within the carcass of the dishwashing machine 2, by the side of the tank 4.

The rinsing system 6 comprises, in turn, a heating tank or boiler 7 for the rinsing water to be fed in use into the chamber 3, means 8 (in this case consisting of a tube) for feeding the water from a water network 9 (figures 4 and 6) to the boiler 7; hydraulic disjunction means 10 arranged upstream of the boiler 7 and comprising a tank 11, open to the atmosphere and into which the tube 10 leads in an open discharge manner, and a feeding tube 12 feeding water by gravity from the tank 11 open to the atmosphere to the boiler 7; and a pump 13 (figure 4) for drawing hot water from the boiler 7 for conveying it in a pressurized state to the washing chamber 3 of the electric household appliance 2.

According to the main aspect of the invention, the rinsing system 6 further comprises an integrated device 1 for feeding the heating tank or boiler 7 and detecting the level of liquid therein, in particular of non-pressurized rinsing water coming precisely from the tube 12, insertable in use onto a feeding mouth 15 of the boiler 7 (figure 4), indeed arranged between the tube 12 feeding water by gravity and the boiler 7. The device 1 (figure 5) consists in an internally hollow body 20 divided into three compartments 21, 22, 23 connected to one another to form corresponding vessels communicating by means of a base portion 24 of the body 20 intended in use to be arranged downwards (figure 6) and from which the three compartments 21,22,23 transversally and overhangingly extend so as to be vertically oriented in use.

The compartments 21 and 22 are arranged immediately adjacent to each other and are provided, at the corresponding free ends thereof (i.e. at the corresponding tops, given their vertical arrangement in use), the first with a hydraulic connecting element 26 to a liquid feeding pipe, in this case to the tube 12, and the second with an air vent 27, and are both hydraulically connected by means of the base portion 24 to a tube 30 fluid-tightly connectable in use to the feeding mouth 15 of the boiler 7, which tube 30 is integrally obtained with the body 20 and is internally provided with a transverse wall 31, oriented parallelly to the direction of overhanging extension of the three compartments 21,22,23 (vertically, in this illustrated case), and which extends into the base portion 24 to create in use a first pipe 32 and a second pipe 33, reciprocally parallel and separate, for the connection to the boiler 7 for the first 21 and second 22 compartments, respectively.

The second compartment 22 is further hydraulically connected to the third compartment 23 through a bottleneck 36 in the base portion 24 forming in use, toward the compartment 22, a siphon or air trap 37 together with the internal volume of the compartment 23; furthermore, the latter carries a pressure inlet or nipple 38 connectable in use to a manostat PM known per se (figure 4) at the free end or top thereof.

The compartments 21,22,23 are defined by corresponding portions 41,42,43 of the body 40 which laterally extend to the base portion 24, in use over the same, reciprocally separated by a corresponding first 45 and second 46 slot-shaped openings, open towards the free ends of the compartments 21,22,23 and blind towards the base portion 24, each opening 45,46 ending towards the bottom wall 47 of the base portion 24, opposite to said compartments 21,22,23, with a rounded end 48,49, respectively.

The tube 30 is integrally obtained in one piece with the body 20 on the middle line of the opening 45 which separates the compartments 21 and 22, and has an external diameter substantially equal to a distance D (figure 5) between the bottom wall 47 of the base portion 24 and the rounded end 48 of the opening 45; the tube 30 further carriers the wall 31 arranged substantially aligned with the opening 45, parallelly to the longitudinal extension of the same which, in use, is in the vertical direction.

On the other hand, the bottleneck 36 of the base portion 24 is defined by the distance d (figure 5) between the bottom wall 47 and the rounded end 49 of the opening 46, which distance d is smaller than the distance D between the same bottom wall 47 of the base portion 24 and the rounded end 48 of the opening 45.

Preferably, the portions 41,42,43 of the body 20 defining the compartments 21,22,23 are mechanically connected to one another by stiffening ribs 50 arranged within the openings 45,46, transversally to the same and substantially over their whole lengthwise extension.

The body 20 is further shaped so that the tube 30, integrally obtained therewith, transversally and overhangingly extends from the body 20 with respect to both the base portion 24 and the three compartments 21,22,23, so as to be oriented parallelly to the mouth 15 in use, i.e. in the horizontal direction.

The compartment 23 forming in use the siphon 37 along with the bottleneck 36 is obtained so as to be immediately adjacent to the compartment 22 and is arranged symmetrically opposite to the compartment 21 with respect to the intermediate compartment 22; the three compartments 21,22,23 preferably have a parallelepiped shape and are substantially arranged coplanar with respect to an overall laying plane of the internally hollow body 20.

The latter is preferably made of synthetic plastic material molded in one piece or consists of a pair of cup-shaped half shells 81,82 reciprocally and fluid-tightly joined along corresponding peripheral edges 83 by welding and/or gluing.

In all cases, according to the rinsing system 6 according to the invention, the device 1 is arranged in use with the first compartment 21 connected by means of the hydraulic connection element 26 thereof to the feeding tube 12 of water by gravity and the tube 30 integrally obtained with the internally hollow body 20 is connected to the inlet mouth 15 of the boiler 7, e.g. fluid-tightly driven thereon or therein, according to the relative dimensions of the same.

In virtue of the described shape and position of the device 1, the boiler 7 is further provided, as the sole other openings for the connection to the outside in addition to the mouth 15, only with a hydraulic connection 90 to the pump 13 and with an upper venting tube 92 connected to the tank 11 open to the atmosphere.

In use, the water from the water network 9 follows the path shown by the arrows in figure 6, leading in an open discharge manner into the tank 11 open to the atmosphere, thus loosing its pressurization. From here, it proceeds by gravity into the tube 12, while possible air bubbles are evacuated through the vents 100 (figure 6).

Subsequently, the water enters the compartment 21 of the integrated device 1 defined by the hollow body 10 and through the pipe 33 penetrates the boiler 7, thus expelling the air contained therein through the vent 92, which is obviously arranged at the higher part of the boiler 7 for this purpose; the air may be for example conveyed into the tank 11 open to the atmosphere through an appropriate tube.

As soon as the boiler 7 starts filling up, the inlet water exits from the same through the pipe 32 and fills the compartment 22 and, then, through the bottleneck 36, the compartment 23 while the air contained in the compartment 22 is evacuated through the vent 27, thus allowing the water to overcome the bottleneck 36. On the contrary, the air contained in the compartment 23 is kept trapped inside the siphon 37 formed by the same and by the bottleneck 36 toward the compartment 22 and increases in pressure, thus allowing to measure the liquid level in the compartment 23 (which is identical to that in the boiler 7, due to the communicating vessels defined by the compartments 21,22,23) by means of the manostat PM.

Claims

1. An integrated feeding and liquid level detecting device (1) for a tank (7), in particular of non-pressurized rinsing water in a boiler (7) of a dishwasher (2), insertable in use onto a feeding mouth (15) of the tank; characterized in that it consists of an internally hollow body (20) divided into three compartments (21,22,23) reciprocally connected to form corresponding vessels communicating by means of a base portion (24) of the body intended in use to be arranged downwards and from which the three compartments transversally and overhangingly extend so as to be vertically oriented in use, wherein a first and a second compartments (21,22) are arranged immediately adjacent to each other and are provided, at the corresponding free ends, the first with a hydraulic connecting element (26) to a feeding pipe (12) of said liquid and the second to a vent (27), and are both hydraulically connected by means of the base portion (24) to a tube (30) fluid-tightly connectable in use to the feeding mouth of the tank, which tube (30) is integrally obtained with the body (20) and is internally provided with a transverse wall (31) oriented parallelly to the direction of overhanging extension of the three compartments, and which extends into the base portion to create in use a first and a second connecting pipes (32,33), reciprocally parallel and separate, to the tank for the first (21) and second (22) compartments, respectively.

2. A device (1) according to claim 1, characterized in that said second compartment (22) is hydraulically connected to the third compartment (23) by means of a bottleneck (36) in the base portion forming a siphon (37) towards the second compartment; the third compartment (23) carrying at its free end a pressure inlet (38) connectable in use to a manostat (PM).

3. A device (1) according to claim 2, characterized in that said compartments (21,22,23) are defined by corresponding portions (41,42,43) of the body (20) which extend laterally to the base portion (24), in use over the same, reciprocally separated by a corresponding first (45) and second (46) slot-shaped openings open towards the free ends of the compartments and blind towards the base portion (24), each opening ending towards the bottom wall (47) of the base portion, opposite to said compartments, with a rounded end (48,49).

4. A device (1) according to claim 3, characterized in that said tube (30) integrally obtained with the body (20) is obtained in the middle of the first opening (45), which separates the first compartment (21) from the second compartment (22), displays an external diameter essentially equal to the distance (D) comprised between said bottom wall (47) of the base portion (4) and said rounded end (48) of the first opening (45) and carries said wall (31) aligned with the first opening (45), parallelly to the same.

5. A device (1) according to claim 3 or 4, characterized in that said bottleneck (36) of the base portion (24) which forms a siphon (37) towards the second compartment is defined by the distance (d) comprised between said bottom wall (47) of the base portion (24) and said rounded end (49) of the second opening (46), which is smaller than that (D) comprised between the same bottom wall (47) of the base portion and the rounded end (48) of the first opening.

6. A device (1) according to one of the claims from 3 to 5, characterized in that said portions (41,42,43) of the body (20) defining said compartments (21,22,23) are reciprocally and mechanically connected by stiffening ribs (50) arranged within said openings (45,46).

7. A device (1) according to any of the preceding claims, characterized in that said tube (30) is integrally obtained with the body (20) and extends transversally and overhangingly from the same with respect to both the base portion (24) and the three said compartments (21,22,23).

8. A device (1) according to any of the preceding claims, characterized in that the third compartment (23) is immediately adjacent to the second compartment (22) and arranged symmetrically opposite to the first compartment (21); the three compartments (21,22,23) being essentially parallelepiped-shaped and being arranged essentially coplanar with respect to an overall laying plane of said internally hollow body (20).

9. A device (1) according to claim 8, characterized in that said internally hollow body (20) is made of a synthetic plastic material molded in one piece or consists of a pair of cup-shaped half shells (81,82) reciprocally and fluid-tightly

joined along the corresponding peripheral edges (83) by welding and/or by gluing.

10. A hot rinsing system (6) for an electric household appliance, in particular a dishwasher (2), comprising: network water feeding means (9); a boiler (7); hydraulic disjunction means (8) arranged upstream of the boiler and comprising a tank (11) open to the atmosphere into which the network water feeding means (9) lead in an open discharge manner and a gravity water feeding tube (12) from the tank open to the atmosphere to the boiler (7); and a pump (13) for drawing hot water from the boiler and conveying it in a pressurized state to a washing chamber (3) of the electric household appliance (2); characterized in that it further comprises a device (1) according to any of the preceding claims arranged between the gravity water feeding tube (12) and the boiler (7) with the first compartment (21) connected by means of the hydraulic connection element (26) thereof to the gravity water feeding tube (12) and the tube (30) integrally obtained with the internally hollow body (20) connected to an inlet mouth (15) of the boiler (7); the latter being further provided only with a hydraulic connection (90) to said pump and with an upper venting tube (92) connected to the tank open to the atmosphere.

11. An electric household appliance (2), in particular a front-loading dishwater, comprising a washing chamber (3) and a rinsing system (6) according to claim 10.