EP0381586A1 - Method for acoustically insulating noise sources in a dishwasher, and dishwasher using said method - Google Patents

Abstract

Method for acoustically insulating noise sources in a dishwasher, characterised in that it consists in: - the positioning, in particular of motor-pumps for drainage and recycling of a spraying liquid (68), inside the tank (57) of this dishwasher (55), and in - acoustically insulating them from the exterior by this tank (57). <IMAGE>

Description

The present invention relates to a method of acoustically isolating sources of noise in a dishwasher, and a dishwasher implementing this method.

A dishwasher usually comprises outside, a body providing mechanical protection and an aesthetic coating, and inside, on the one hand, a tub containing dish baskets and watering reels, and on the other hand, organs supplying coolant and heating liquid and control accessories. These organs are mainly recycling and emptying pumps, their drive motor and suction and discharge lines for coolant. In such a dishwasher, sources of noise are numerous and originate not only from watering reels, suction and discharge lines for coolant, impacts between the jets of liquid and the dishes and between the pieces of tableware but also of the pumps and their drive motor.

Solutions have been proposed and carried out in dishwashers known to reduce and / or isolate these sources of noise. Although encouraging results have been recorded, these known dishwashers are still noisy during operation.

The object of the present invention to avoid these drawbacks is an economical and effective method of acoustically isolating sources of noise in a dishwasher, and a dishwasher implementing this method.

According to the invention, a method of acoustic isolation sources of noise in a dishwasher is characterized in that it consists of:
- in particular have motor pumps for emptying and recycling the coolant, inside the tank of this dishwasher, and
- acoustically isolate them from the outside by this tank.

• - la figure 1 représente une vue schématique et partielle d'un premier type de lave-vaisselle connu,
• - la figure 2 représente une vue schématique et partielle d'un deuxième type de lave-vaisselle connu,
• - la figure 3 représente une vue schématique et partielle d'un troisième type de lave-vaisselle connu,
• - la figure 4 représente une vue schématique et partielle d'un quatrième type de lave-vaisselle connu, et
• - la figure 5 représente une vue schématique et partielle d'un lave-vaisselle mettant en oeuvre l'invention.

In order to better understand the invention, a few known dishwashers and an example embodiment of a dishwasher implementing the invention are described below, illustrated by the attached drawings, of which:

• FIG. 1 represents a schematic and partial view of a first known type of dishwasher,
• FIG. 2 represents a schematic and partial view of a second known type of dishwasher,
• FIG. 3 represents a schematic and partial view of a third type of known dishwasher,
• FIG. 4 represents a schematic and partial view of a fourth type of known dishwasher, and
• - Figure 5 shows a schematic and partial view of a dishwasher implementing the invention.

According to a first known type illustrated in Figure 1, a dishwasher 1 comprises a body 2 closed by a front door not shown, a tank 4 containing a lower dish basket 5, an upper dish basket 6, a reel lower sprinkler 7, an upper sprinkler reel 8. The lower 7 and upper sprinkler reels 8 are supplied with coolant by a recycling pump 10 through respectively a lower discharge line 11 and an upper discharge line 12. The recycling pump 10 is driven by an electric motor 14. The coolant is evacuated from the tank 4 by a drain pump not shown. In this first known type of dishwasher, the recycling pump 10 and its drive motor 14 often form a monolithic pump unit 10-14 mounted outside of the tank 4 and in below the bottom 16 thereof. A suction line 18 connected to the inlet of this recycling pump 10 at the bottom 16 of the tank 4. The lower discharge line 11 and the upper discharge line 12 pass through openings respectively in the bottom 16 and in an upper wall 20 of the tank 4, the leakage tightness of which is ensured by seals 21, 22.

During the operation of the dishwasher 1, apart from the operating noises specific to the pump 10 and to the drive motor 14, vibrations of the pump unit 10-14 which are transmitted to the tank 4 through the suction line 18 and the discharge lines 11 and 12 also constitute an important source of noise. To eliminate this source of noise, a vibration decoupling of the pipes 11, 12 and 18 is carried out in the dishwasher 1. For this purpose, the pipes 11, 12, 18 are generally made of a flexible material and the suction pipe 18 has at least in part of its length a shape of a bellows. In addition, these pipes are not often connected directly to the walls of the tank 4 but by means of a piece of synthetic material 25 tightly fixed with an elastic seal 26 on the bottom 16 of the tank 4 and serving to both of a support for the pipes 11, 12, 18 and of a liquid supply well 27 of the pump 10.

In a second known type illustrated in FIG. 2, a dishwasher 30 comprises, apart from the same elements indicated by the same reference numbers as those of the dishwasher 1 of the first known type (FIG. 1), a discharge line upper 32 which is mounted inside the tank 4, and an elastic suspension 33 which provides vibratory decoupling of the pump unit 10-14.

These first two known types of dishwasher 1 and 30 with their pump unit 10-14 mounted outside their tank 4 are a relatively simple construction which allows a possible evolution of this pump unit 10-14 without changing deeply the structure of these dishwashers 1 and 30. However, a great drawback in these dishwashers is the fact that airborne noises from their pump unit 10-14 and their pipes 11, 12, 18 mounted outside from their tank 4 radiate directly to the outside, noises resulting from a vibratory transmission by these pipes 11, 12, 18 and from this pump unit 1-14 to their tank can already be partially eliminated, at a significant additional cost. Another disadvantage is that the risk of leakage is increased.

In these two known types of dishwasher 1 and 30, the sources of noise inside their tank 4 which have their origin, their lower 7 and upper 8 reels in rotation, their discharge lines in action, impacts of the jets of liquid on the dishes and between the pieces of dishes, are largely insulated from the outside by walls of their tank 4 frequently reinforced in thickness by a layer of a sound insulator such as bitumen. However, areas of the walls of their tank 4, occupied by openings for crossing the pipes 11, 12, 18 and / or by the mounting opening of the piece of synthetic material 25 serving to support these pipes 11, 12, 18 and of the liquid supply wells of the pump 10, are poorly sound insulated and constitute easy passages for the noises occurring inside the tank of these dishwashers 1 and 30.

According to a third known type illustrated in FIG. 3, a dishwasher 36 comprises, apart from the same elements indicated by the same reference numbers as those of the dishwasher 1 of the first known type (FIG. 1), on the one hand a recycling pump 38 and a lower discharge line 39 mounted inside the tank 4, and on the other hand, a drive motor 40 of the pump 38 and an upper discharge line 42 mounted outside of the tank 4 and fixed thereto by means of a plastic insert 43 and a seal 44. The insert 43 serves both as a support for fixing the drive motor 40 and a liquid supply well of the pump 38. The shaft 46 of the drive motor 40 and the upper discharge line 42 are mounted through through holes formed in the walls of the plastic insert 43, which are made liquid-tight respectively by a tight rotating joint 47 and a sealing joint 48.

In a fourth known type (Figure 4) which is an alternative embodiment of the third known type (Figure 3), a dishwasher 50 comprises a recycling pump 38, lower 30 and upper discharge lines 51 mounted inside of the tank 4, and a drive motor 40 fixed to the outside of the tank 4.

The third and fourth known types have the advantage of a simpler construction than those of the first and second known types. A rotary joint usually existing in a pump unit between the pump and the drive motor is transposed in this construction (FIGS. 3 and 4) into a tight rotary joint 47 mounted on the insert 43. A risk of external liquid leakage is present in the third known type (Figure 3) at the seals 44 and 48 and the waterproof rotating joint 47 and in the fourth known type (Figure 4) at the sealing joint 44 and the waterproof rotating joint 47 .

In this construction, a vibration decoupling of the drive motor 40 is obtained not only at the cost of a tight vibration decoupling at the level of the plastic insert 43 to which the drive motor 40 is fixed, but also of a waterproof vibratory decoupling rotating at the through hole in this insert 43 for the shaft 46 of this drive motor 40, in particular for low frequencies of the order of a few tens of Hertz.

This vibratory decoupling is thus in practice resolved according to either a satisfactory specific solution but expensive, a mediocre but economical bastard solution. Whatever the result of this vibration decoupling, the drive motor 40 which is located outside the tank 4 of these devices 36, 50, radiates airborne noise directly to the outside.

In these known devices, although the noises produced inside the tank 4 are phonically isolated by the walls of this tank 4, these noises however come out through bushings or passages and parts which are poorly phonically insulated in the walls of the tank 4 such as the bottom part 16 of tank 4 occupied by the plastic insert 43.

The present invention avoids these drawbacks.

According to the invention, a method of acoustically isolating sources of noise in a dishwasher consists in particular of disposing of drain and recycling pumps and their drive motor inside the tank of this dishwasher. and to acoustically isolate them from the outside by this tank.

In this acoustic isolation, the tank of the device is a tank having solid walls devoid of openings and / or crossings forming easy or free passages to acoustic waves.

According to the invention, the method of acoustically isolating noise sources in a dishwasher comprises sound insulation of the tank of the appliance by a homogeneous coating by means of sound insulation, on the one hand, of the walls and the door of this tank, and on the other hand, openings and / or bushings in the walls of this tank, forming easy or free passages for acoustic waves.

This soundproofing is carried out by means of an insulator chosen from bitumens, rubbery or polyurethane-based materials, synthetic materials possibly supplemented with plastic foam, felts, glass wool or rock wool and building materials with high absorption capacity.

In an exemplary implementation of this method of acoustically isolating sources of noise in a dishwasher, a dishwasher 55 illustrated schematically and partially in FIG. 5 comprises a body 56 and a tank 57 provided with an opening front closed by a front door (not shown), with side, upper and rear solid walls, and with a bottom wall 60 constituted by a full stamped wall forming a sump 61. Inside the tank 57 are mounted a basket with lower crockery 63, an upper crockery basket 64, an upper watering reel 66, a group of recycling and draining motor pumps 68, a lower coolant discharge line 71 and an upper liquid discharge line d sprinkler 72. The group of motor pumps 68 which is constituted by a group of submerged motor pumps is mounted in the sump 61 of the tank 57 on an elastic support 74 which provides isolation v ibratory in particular for low frequencies of the order of a few tens of hertz. The sump 61 is intended both for receiving the group of motor pumps 68 and for collecting the coolant.

The usual sources of noise in the dishwasher 55 such as those constituted by the group of motor pumps 68, the sprinkler reels 65, 66, the lines for discharging the coolant 71, 72, impacts between jets of liquid watering and the dishes and shocks between the parts of these dishes are all inside the tank 57. To acoustically isolate them from the outside in the dishwasher 55, the outer surfaces of the tank 57 including the rear, upper and bottom side walls 60 advantageously constitute by solid walls, that is to say devoid of openings or crossings forming easy or free passages for acoustic waves, are throughout their extent uniformly furnished a layer of insulation phonic such as bitumen, the front door of the tank 57 is also soundproofed.

As a result, the dishwasher 55 is extremely silent during its operation since its usual sources of noise are effectively acoustically isolated by a tank 57 surrounded in a homogeneous manner over the entire extent of the surface of its walls by a excellent envelope in sound insulation.

In the dishwasher 55, produced according to the invention, the coolant circuits, that is to say the group of motor pumps 68, the discharge lines 71, 72, the sprinkler reels 65, 66 mounted inside the tank 57 require only a seal relating to liquid leaks, at their connection or connection points where a leak of liquid within tolerated limits does not compromise a good operating result of the washer - tableware but reflects a great manufacturing tolerance which makes it particularly economical. Their vibration isolation is much easier technically and more economically than that of the spraying liquid circuits in known dishwashers mentioned in previous paragraphs where their vibration isolation is often coupled with a seal essential for leaking liquid. A provision of immersion of the group of motor pumps 68 in the coolant collected in the sump 61 of the tank 57 not only simplifies the structure of this group 68 resulting in the elimination, for example, of the suction lines of the pumps and a reduction from these to short inlet pipes 76 but also effective cooling of their drive motor. Consequently, this drive motor can be an engine of economical construction.

In the dishwasher 55, a possible significant leak of liquid at the coolant circuits can greatly reduce the hydraulic efficiency of these circuits, but does not entail any risk of flooding, which eliminates in this device 55 the usual and expensive means of detecting leakage of liquid found in known dishwashers.

Claims (5)

1. A method of acoustically isolating sources of noise in a dishwasher, characterized in that it consists in: - having in particular motor pumps for emptying and recycling the coolant (68), inside of the tank (57) of this dishwasher (55), and
- Acoustically isolate them from the outside by this tank (57) whose walls, door, openings and / or crossings are provided with a coating of sound insulation. 2. Method according to claim 1, characterized in that the tank (57) is provided with a sound-insulating coating and devoid of openings and / or bushings forming easy passages for acoustic waves. 3. Method according to claims 1 and 2, characterized in that the sound insulation of the tank (57) is chosen from bitumens, rubbery materials or based on polyurethane, synthetic materials possibly supplemented with plastic foam, felts, glass or rock wool and building materials with high absorption capacity. 4. Dishwasher implementing the method according to one of claims 1 to 3, characterized in that it comprises as group of motor pumps for recycling and emptying (68), a group of submerged motor pumps. 5. Dishwasher according to claim 4, characterized in that the group of motor pumps (68) is mounted in the sump (61) by means of an elastic support (74) which provides vibration isolation in particular for low frequencies on the order of a few tens of hertz.

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