EP0178031B1 - Washing machine with a device for determining the turbidity of the water - Google Patents

Description

The invention relates to a machine for lifting laundry or the like, comprising a device for measuring the turbidity of the water which contains suspended particles, a device which makes it possible to adapt the durations and / or quantities of water necessary for the execution of washing and / or rinsing operations in the soiled state of the laundry, and which comprises a light source (s) and a light detector (s) which determines the flow light remaining after the light has passed through the washing or rinsing water, the device being fixed to a wall integral with the tank of the machine.

In washing machines, the washes are carried out in a given quantity of water to which detergents are added, the whole being stirred and possibly heated to a temperature above ambient. Detergents combine with grime and laundry debris so that grime is removed from the laundry and forms small piles, part of which is removed with the washing water and the other part, remaining in the laundry, is evacuated by rinsing with pure water, generally cold city water, this rinsing being effected either according to successive cycles of water admission and evacuation, or with continuous admission and evacuation of water.

It follows that, firstly if the laundry is abnormally dirty or too heavy or, if too much detergent has been used, the washing and rinsing times may be too short for the laundry to be properly washed and rinsed or secondly, when the laundry is lightly soiled, these same times can be too long and this results in an exaggerated expenditure of energy for washing and too much water consumption for rinsing.

To fix the optimal duration of washing in the presence of detergent, or is based on the fact that during washing, the water becomes charged with impurities and that its opacity to light tends towards a certain limit corresponding to the complete washing of the laundry, said limit being a function of the quantity of laundry and its soiling.

Similarly, to automatically adjust the amount of water required to rinse the laundry, it is known to measure the purity of the water. For this, the degree of purity of the rinsing water is continuously measured, in an area taken by this rinsing water, and when the measured purity reaches a defined limit, close to the purity of the water before it is introduced into the machine, a control device causes the water intake to stop.

A device for detecting the opacity and purity of water, which is called a turbidimeter, has been described in KOKAI No. 54.66567. It includes a light source sending a light flux, which, after passing through an area receiving the water stirred in communication with the tank of the machine arrives on a light detector which determines the transparency of the water. The light source and the detector are placed in an area formed by a protuberance from the tank. The detector is placed in the axis of the incident light beam to measure the transmitted light.

But for this type of turbidimeter, which performs measurements in an area in direct contact with the tank water, the movements of the water and those of undissolved detergent particles, bubbles, dirt, etc ... , greatly disturb the measurements and make them difficult to use.

The object of the invention is thus to enable measurements which are not erratic, but truly representative of the state of opacity and / or purity of the water in the tank.

For this the invention as defined in the preamble is remarkable in that the measuring device, arranged on its wall, is surrounded by an envelope or protected by at least one plate, which, while ensuring the renewal of water and the evacuation of the particles in suspension through openings, creates a zone of non-turbulence in which the measuring device operates.

To allow measurements of the opacity of the washing water or the clarity of the rinsing water, the turbidimeter will be able to perform respectively transmission measurements or measurements of diffusion of the luminous flux through the water to be studied. . The diffusion measurements will be made by placing the light emitter and the receiver off-axis with respect to each other. The transmission measurements will be made by placing the light emitter and receiver in the axis of each other, or if necessary off-axis if we use a mirror to deviate towards the receiver, the light beam from the light emitter.

According to a first embodiment, the transmitter sends and the light receiver receives their respective light fluxes through light guides placed very close to each other on a waterproof support, the light beam, after that it has passed through a sufficient thickness of water, being deflected towards the receiver by a mirror. This waterproof support may consist of a molded rubber element or of a rigid material, such as a plastic or metallic material, fixed to the tank of the machine.

The measurement area is therefore located at the end of the light guides placed in the water of the machine. According to the invention, the entire part of the turbidimeter located in the tank is surrounded by an envelope in which a non-turbulence zone is created, while ensuring the renewal of the water by openings: According to this first embodiment and preferably , the light pipes are arranged substantially horizontally. In this case the envelope has a frustoconical shape, the widest section being placed on the side of the wall of the tank. The openings, placed at the top and bottom of the enclosure, which ensure the renewal of the water without harming the non-turbulence of the measurement area are placed so that light particles such as air bubbles, light waste, etc. escape upwards while heavy waste settles downwards. In the narrowest part of the frustoconical envelope are also distributed upper and lower openings but their main role is to allow a regular and slow renewal of the water to be studied. The area where the measurements are made is free of openings to ensure a certain state of non-turbulence.

According to a second embodiment, the light emitter and receiver are fixed individually in the axis of each other, and in a sealed manner, on a part of the tank forming an external protuberance in order to determine a measurement area. This protuberance has a frustoconical shape, the widest section also being on the side of the wall of the tank, this as in the previous mode in order to facilitate the migration of light particles upwards and that of heavy waste downwards. Significantly in the extension of the wall of the tank, the excavation is partially closed off with a plate which releases the upper and lower openings necessary for the renewal of the water.

• figure 1: une vue schématique d'une machine à laver le linge munie d'un turbidmètre protégé selon l'invention,
• figure 2: une vue de dessus en coupe détaillée d'un turbidimètre muni de son enveloppe de protection, _..
• figure 3: une vue de côté en coupe du turbidimètre,
• figure 4: une vue de côté du support de fixation,
• figure 5: une section de l'enveloppe au voisinage de la fixation du turbidimètre sur la cove,
• figure 6: un second mode de réalisation de l'invention pour laquelle le turbidimètre monté dans une excroissance de la cuve,
• figure 7: une variante du second mode de réalisation.

The invention will be better understood using the following description and the drawings which represent:

• FIG. 1: a schematic view of a washing machine with a protected turbidmeter according to the invention,
• FIG. 2: a top view in detailed section of a turbidimeter provided with its protective envelope, _..
• FIG. 3: a side view in section of the turbidimeter,
• FIG. 4: a side view of the fixing support,
• FIG. 5: a section of the envelope in the vicinity of the attachment of the turbidimeter to the cove,
• FIG. 6: a second embodiment of the invention for which the turbidimeter mounted in a protuberance from the tank,
• Figure 7: a variant of the second embodiment.

In Figure 1 is shown schematically a washing machine 10 provided with a tank 11 in which a drum 12 rotates about an axis of rotation 13. The operating cycle can be alternated in the two directions of rotation A and B. At the bottom of the tank 11 is arranged the turbidimeter 20 with its protection according to the invention, its main axis being horizontal. The protection has an oblong frustoconical shape on which the upper 21, lateral 22 and lower 23 parts are identified. Depending on the direction of rotation of the drum, it is noted that the water projections created by this rotation will mainly appear on the upper part 21 for the direction of rotation B and on the side 22, and lower 23 for the direction of rotation A. The turbidimeter 20 will deliver electrical signals to a control device 15 which acts on the programmer 16 of the washing machine to adjust water intake and / or washing and / or rinsing times.

In Figures 2 and 3 is shown the turbidimeter respectively by a top view and a side view. In FIG. 1 is shown the tank 11 in which an opening is made in which the turbidimeter is inserted using a support 30 which preferably is made of rubber in order to ensure both sufficient mechanical strength and sealing at the water. This support 30 adapts forcibly to the tank 11 and is waterproof thanks to its peripheral configuration in the form of lips. Through this support 30 pass light guides 40, 41, 42 respectively rigidly coupled to the light emitter 45, to the light receiver 46, and to the light emitter 47. The light guides are transparent to light which passes through them and are made, for example, of glass. These light guides pass through the rubber support 30 with tight friction, thus ensuring water tightness. These light guides 40, 41, 42 are arranged with a slight friction in a support element 31 made of rigid plastic material interteen in water, for example rilsan. This support element 31 has substantially a flat and elongated parallelepiped shape, this being a consequence of the line arrangement chosen for the two emitter and the light receiver (FIG. 4). Another provision could lead to an adapted form of this support element. Opposite the rubber support, where the light leaves the light guides 40, 42 coupled to the light emitters 45, 47, the support element 31 has a particular shape. It comprises first of all two faces provided with twin mirrors 35, 36, placed in such a way that the light coming from the light guide 40 arrives in the direction and enters the light guide 41 coupled to the light detector 46. A third mirror 37 is placed in the axis of the light guide 42 in order to reflect the light in the direction of the measurement area 38. This measurement area 38 is located substantially in the axis of the light guide 41 coupled to the light 46. The mirrors 35, 36, 37 are for example made up of small polished pieces of stainless steel mechanically fixed to the support element 31. The roles of the mirrors 35 and 36 on the one hand and that of the mirror 37 on the other hand are different. Lex two mirrors 35 and 36 are intended to define a path of propagation of the light flux in order to determine the transmission of water; in this case it is a question of testing the transparency of the water. The role of the mirror 37 is to return the luminous flux in the direction of the measurement zone 38 where a diffusion of the light will take place by the rinsing water loaded with detergent: in this case it is a question of determining the water clarity. These measurements can only be made in a non-turbulent measurement area. For this, the entire turbidimeter is surrounded by a casing 25 preferably made of rubber. This envelope 25 which is force fitted, is locked in position by two plates 32, 33 integral with the support element 31. To ensure the renewal of the water, it is necessary to provide this envelope 25 with a certain number of openings which must be made in specific sectors. It is necessary to avoid that the flows are made too directly on the measurement zone 38. For this, as indicated in FIG. 3, openings are made in the upper 21 and lower 23 parts of the envelope. It is desirable that the envelope has a frustoconical shape. Indeed, if we consider what happens during the evacuation of the contents of the envelope, we can reduce this problem to the evacuation of the water itself, that of the heavy particles and that of the light particles and air bubbles. By giving the envelope a frustoconical shape, the light particles will tend to coagulate along the inner surface of the upper part 21 of the envelope 25. The air bubbles in particular will gradually escape through the opening 52. In the same way, the heavy particles will tend to settle and little by little will slide along the inner surface of the lower part 23 of the envelope 25. These heavy particles will be able to escape by l opening 54. The plate 32 has not only the role of supporting the casing 25 but also that of creating an intermediate zone with the measurement zone 38. This intermediate zone will also have openings 51, 53 respectively in the upper parts 21 and lower 23 of the envelope 25. The same mechanism for removing light and heavy particles as described above will be carried out there. Apertures 57, 58 are provided in the plate 32 which ensure the passage of water from the intermediate zone to the measurement zone. The openings 51, 52, 53, 54 have not only the role of evacuating the particles described but also that of renewing the water in the turbidimeter. The additional openings 55 and 56 placed, them, in the narrowest part of the frustoconical shape of the envelope are more particularly requested by the renewal of the water.

It is to better define a global diagram that the opening 55 has been represented as it is in FIG. 3 in order to facilitate the description of the evacuation and renewal mechanisms. A more suitable position is shown in FIG. 2, that is to say that the measurement area 38 being that indicated therein, the opening 55 is placed facing the support element 31 in order to avoid maximum direct passage of water through the measurement zone 38. The support element 31 has openings 59 ensuring the passage of water. For the same reasons, FIG. 5 shows according to the view shown that the opening 51 does not have the same axis as the opening 57 in order to avoid the direct passage of water from the opening 51 to the opening 57. Cesi is also true for the openings 58 to 53. The lateral part 22 is not provided with openings to avoid that during the rotation of the drum in the direction A (FIG. 1) the projections of water which then take place on this lateral part does not disturb the effectiveness of the protection. For the same reasons the turbidimeter 20 should be placed in the tank preferably towards one of the end walls, that is to say towards the front face or the rear face of the tank as shown in FIG. 1 so that the openings 51, 52, 55 shown in Figure 2 are rather directed towards said previous end wall.

For a turbidimeter having a length of approximately 10 cm mounted on a support having approximately 10 cm in diameter, openings having a diameter of approximately 5 millimeters have been satisfactory.

In Figure 6 is shown a second embodiment according to the invention. The frustoconical envelope in this case consists of a protuberance of the tank which has this frustoconical shape. This frustoconical form is motivated by the same reasons as those described in the first embodiment. The light emitters 45, 47 and the light receiver 46 are shown here with a different arrangement. In order to ensure a non-turbulence state in the measurement zone, the protuberance in the tank is closed by a plate 60 which is for example a rubber plate introduced by force and held in position by the elasticity of the material. Openings 61 to 63 will have the same role as the openings 51, 52, on the one hand, and 53 and 54, on the other hand, in the previous embodiment. Likewise, the openings such as 65, 66 play a role similar to the previous openings 55, 56.

According to a variant variant of this second embodiment, the protuberance is closed off by two plates 60, 70 thus creating an anteroom as in the case of the first embodiment. These two plates have holes arranged in a baffle as were holes 51 and 57 or 53 and 58 respectively in the first mode.

The invention in these two embodiments has just been described with a light receiver 46 associated with two light emitters 45 and 47. It is quite obvious that it is quite possible to replace the light receiver 46 by a light emitter on condition that the reverse operation is carried out for emitters 45 and 46. The operating mode remaining the same in these two, namely that during the washing operation the turbidimeter measures the opacity of the wash water by determining the flow of transmitted light. The control device 15 first of all determines the opacity, which is exploited according to the usual criteria, for example an opacity which no longer increases over time, then intervenes on the programmer 16. In the same way, when rinsing operation the turbidimeter measures the clarity of the rinsing water by determining the flow of scattered light. The control device 15 determines the clarity according to the usual criteria, for example by comparison with a predetermined threshold. This control device then intervenes on the programmer 16.

It is obvious that, depending on the design of the machine and the space available for the turbidimeter, the latter may be arranged in other orientations, for example parallel to the axis of rotation of the drum. The principle of the invention being to protect the measurement zone by an envelope or a protection in order to define a zone of non-turbulence, while maintaining a suitable renewal of the water.

The invention has just been described for a device combining the light transmission and scattering measurements relating to the washing and rinsing operations. It is obvious that this invention applies to washing operations and rinsing operations implementing the invention in two separate devices.

Claims (4)

1. A laundry or other washing machine, comprising a device for measuring the turbidity of water containing suspended particles, which device enables the length and/or the quantities of water necessary for the washing and/or rinsing operations to be adapted to the degree of soiling of the laundry and which comprises a light source or sources (45, 47) and a detector or detectors (46) for said light in order to determine the residual luminous flux passage of after the light through traversed the washing or rinsing water, the device being secured to a wall which is rigidly connected to the tub (11) of the machine, characterized in that the measurement device arranged on said wall is surrounded by an envelope (25) or shielded by at least one plate (60; 60, 70), to provide a zone without turbulence in which the measurement device operates, openings (51-58; 61-63, 65, 66) allowing the water to be renewed and suspended particles to be discharged.

2. A laundry or other washing machine as claimed in Claim 1, characterized in that the openings (51-58; 61-63, 65, 66) allowing the water to be renewed and suspended particles to be discharged are remote from the measurement zone, said openings being located at the top and bottom of the envelope (25) or of the plate(s) (60; 60, 70).

3. A laundry or other washing machine as claimed in Claim 1 or 2, characterized in that the envelope (25) has a frustoconical shape, the water being renewed and suspended particles being discharged at the side of the largest cross-section of the truncated cone and the measurement being effected in the central part of the truncated cone.

4. A laundry or other washing machine as claimed in Claim 1 or 2, characterized in that the support for the device is constituted by a projecting portion of frustoconical shape, the envelope (25) or the plate(s) (60; 60, 70) being arranged adjacent the part of largest cross-section of the truncated cone where the water is renewed and the suspended particles are discharged.

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