EP1096053B1 - Drying and ironing machine comprising a temperature and humidity dependent regulating device - Google Patents

Abstract

The rotary iron, for laundry, has at least one main rotary cylinder (10-12) and a counter pressure unit (30), together with a drive (20) to carry the laundry through the iron. A monitor (60) registers the absolute value of the steam emerging from the final cylinder (10), linked to a control (50). The control (50) modifies at least two of the three parameters of the temp. of the final cylinder (10), the force applied by the counter pressure unit (30) and the speed of the drive (20), as a function of the relative humidity and the temp. measured by the monitor (60). The monitor has a trap (61,62) to deflect the atmosphere in the vicinity of the final cylinder (10) into a chamber (62) fitted with at least one fan (63). The chamber (62) has at least one humidity sensor (64) and at least one temp. sensor (65). The trap has at least one tube (61) with a narrow dia., with one end close to the outlet from the final cylinder (10), and the other end leading into the chamber (62). The outer surface of the cylinders (10) is covered with an insulating cladding, in turn covered by a heating film or fabric. An Independent claim is included for a laundry ironing operation, where initially the atmosphere in the vicinity of the final cylinder (10) is measured for humidity and temp. The measured humidity is compared with a nominal value. On a deviation from the nominal value, at least two parameters of the ironing action are modified, to bring the measured values into line with the nominal humidity value. Preferred Features: The variations are made as a function of the absolute humidity measurements taken from the relative humidity and temp. Corrections are made if the relative humidity value is outside 95-99%.

Description

The present invention relates to a device making it possible to substantially improve the performance of machines for drying and ironing clothes known under the name of dryer-ironers. The invention also relates to dryer-ironers equipped with the devices according to the invention. The invention will also find applications in the field of dryer-ironers comprising a function of folding the laundry; to a certain extent, the invention can be applied to washing machines comprising a laundry drying function.

Dryer-ironers are widely used in laundries, especially in communities (hotels, hospitals, remand centers ...).

It is known that dryer-ironers operate by means of a main roller or a plurality of main rollers, on which the laundry is wound up. These machines also include a back pressure roller or pad, arranged so that the laundry is compressed between a main roller and the back pressure roller or pad. The main roller (s) are provided with a heating device, which can be either electric, or by combustion of gas or by circulation of vapor. Conveyor belts are used to carry the laundry to the active part of the machine. Drying and ironing are achieved by the combined action of temperature and pressure to which the laundry items are subjected.

A first solution is described in the German patent No. 2219895 filed April 22, 1972 by Grosswàsherei Robert Raatz. This solution consists in regulating the running speed of the main cylinder or cylinders as a function of the temperature of the cylinders and of the humidity measured at the level of the suction duct near each main cylinder.

Another solution is described in European patent application EP 528 745. This solution consists in including a temperature sensor in the wall of the main cylinder or cylinders and in controlling the running speed to the temperature value measured by this sensor. This solution is based on the fact that the wall temperature of the main cylinder or cylinders is the result of the competition between the heating due to the supply of energy and the cooling generated by the supply of water conveyed by the part of laundry.

Other proposals for regulating the running speed as a function of the temperature or the humidity of the laundry have been made. None is really satisfactory, so we often get, with dryer-ironers of the prior art, pieces of linen which are either insufficiently dried, or damaged by excessive local heating. Most often, as a precaution, the running speeds are significantly lower than those which would allow maximum productivity and the energy consumption is higher than what would be strictly necessary. None of the solutions proposed in the prior art is really satisfactory, either from the point of view of the energy consumption of dryer-ironers or in terms of the real performance of these devices in terms of productivity (number of pieces dried and ironed satisfactorily per unit of time).

The object of the present invention is therefore to overcome the drawbacks of the prior art by proposing dryer-ironers which make it possible to impart a constant and homogeneous residual humidity on all the pieces of linen treated, and having better energy efficiency.

This object is achieved by the dryer-ironer according to claim 1.

Further developments of the invention are described in claims 2 to 4.

Another object of the invention is to propose a device for regulating as a function of temperature and humidity, making it possible to impart a constant and homogeneous residual humidity on all the pieces of linen treated, and having better energy efficiency.

This object is achieved by the drying method according to claim 5.

Additional developments of the invention are described in claims 6 to 8.

• la figure 1 représente un schéma simplifié d'une sécheuse-repaseuse selon l'invention,
• la figure 2 représente le diagramme de l'air humide.

Other features and advantages of the present invention will appear more clearly on reading the description below made with reference to the accompanying drawings in which:

• FIG. 1 represents a simplified diagram of a dryer-meal-maker according to the invention,
• Figure 2 shows the diagram of humid air.

The main difficulty in drying and ironing laundry items arises from the fact that the laundry items introduced into the dryer-ironers have a texture, thickness and degree of humidity which can vary considerably. In addition, the premises in which the dryer-ironers are placed may also have various temperature and humidity conditions. Consequently, in order to obtain a linen in a satisfactory state after leaving the dryer-ironers, the invention proposes to regulate automatically the various operating parameters during treatment. This regulatory action must occur not only at the stage of each change of part, but also during the processing of a given part. Indeed, a sheet can have a wetter part than another.

According to the invention, the operating parameters used to optimize drying and ironing are as follows: the temperature of the main cylinder or cylinders, the value of the back pressure applied to the part of linen, the speed of advancement of the pieces of linen in the dryer-ironer according to the invention.

The description of the dryer-ironer according to the invention will now be described with reference to FIG. 1. The dryer-ironer according to the invention comprises, in known manner, at least one cylinder (10 to 12), said to be main, heating and rotary. The main cylinder or cylinders (11, 12) placed most upstream of the path for conveying the pieces of laundry (1), the direction of movement of which is represented by the arrow F, make it possible to preheat each piece of laundry and have a temperature lower than the temperature of the main cylinder (10) located furthest downstream. The cylinder (10) located further downstream, hereinafter called the last main cylinder, is rotated, for example by a belt (21) meshing, on the one hand on the axis of rotation of the last cylinder (10) main, via, for example a pulley, and the other by on the output axis of a motor (20). The motor (20) therefore allows the conveying of the laundry items (1). The dryer-ironer also comprises, in known manner, back-pressure means (30). These back pressure means (30) comprise, for example, a cylinder (30) which presses the piece of laundry (1) against the last main cylinder (10). In known manner, the conveyor path for the laundry pieces (1) is formed, for example, of endless bands which successively wind each of the main cylinders (10 to 12) over at least a portion of circumference and a guide means ( 13) pieces (1) of linen. Each endless belt is frictionally driven by the last main cylinder (10) at a speed corresponding to the speed of rotation of the motor (20). Each endless band is held taut on the main cylinders (10 to 12) by the return cylinders (14, 15), at least one of which is mounted on elastic means. It is possible to provide other means for guiding the pieces of laundry so that they follow the conveying path.

According to the invention, the dryer-ironer comprises means (60) for measuring the temperature and the relative humidity of the atmosphere. prevailing in the vicinity and downstream of the last main cylinder (10). These measurement means (60) are connected to control means (50). These control means (50), on the one hand, process the information supplied by the measuring means (60) to determine the absolute humidity rate (Ha) from the diagram of the humid air shown in FIG. 2, and on the other hand possibly modify as a function of this determination, the adjustment of at least two of the following operating parameters, the temperature of the main cylinder or cylinders, the value of the back pressure applied to the piece of laundry, and the advancement speed of the laundry items in the dryer-ironer, to obtain the desired relative humidity. The information representative of the humidity rate and of the measured temperature is treated in such a way that the relative humidity, measured temperature couple can be analyzed as representative of the absolute humidity characterizing the atmosphere released by the passage of the wet linen on the heated cylinders.

The control means (50) are connected, by means of appropriate control links (53 to 55), to at least two of the following three elements in order to be able to control them: namely the device (100) for heating the last cylinder (10), the back-pressure means, and the motor (20) for rotating the last cylinder (10). The backpressure value will be regulated by action on a mechanical or hydraulic device. Finally, the regulation of the speed of movement of the laundry items in the machine will result from the action on the drive motor (20) and / or the control electronics of this motor (20).

According to the invention, the control means (50) modify the setting of the parameters mentioned below by modifying the operation of the device (100) for heating the last cylinder (10), and / or the back-pressure means, and / or the motor (20) for driving the last cylinder in rotation (10), so that the value of the absolute humidity level is close to 100% and chosen between 95 and 99%. This modification is made as a function of the absolute humidity rate determined from the relative humidity and the measured temperature.

Indeed, theoretical studies and tests carried out by the applicant have unexpectedly shown that the drying and ironing functions result from the evacuation by evaporation of a large quantity of water and from the simultaneous application of a compression on the laundry. This evacuation results in the emission of a large amount of water vapor, in the immediate vicinity of the laundry. Experience shows that when the parameters {temperature, back pressure, scrolling speed} are optimally adjusted, the atmosphere in the immediate vicinity of the laundry is almost saturated with water vapor, i.e. that its relative humidity value is close to 100% RH. If this is not the case, that is to say if a relative humidity value significantly less than 100% is detected, it can be concluded that one of the previously mentioned parameters can be modified as a function of the value of the absolute humidity rate determined by the control means on the basis of the values of the relative humidity rate, the temperature and the humid air diagram represented in FIG. 2.

Take, for example, the drying and ironing of a sheet and suppose that the amount of water contained in this sheet is not uniform over its entire length and that, for example, the sheet is more humid in its front part. From the start of the drying and ironing cycle, the humidity level measured by the measuring means (60) risks being below 100% since the sheet is loaded with moisture and this, taking into account the settings unsuitable anterior, will not be completely extracted. Consequently, the operating parameters must be modified to obtain a relative humidity close to 100%. To do this, the control means (50) determine the value of the absolute humidity rate by means of the measured values of the relative humidity rate and of the temperature, and automatically modify the operating parameters, for example in the case of the sheet, by increasing the temperature of the last main cylinder (10), and / or by decreasing the speed of the drive motor (20), and / or is increasing the pressure exerted by the back-pressure means (30). When the less humid parts of the sheet are going to pass between the last main cylinder (10) and the means (30) of back pressure, the relative humidity rate will decrease since there is less water to evaporate. In this case, the absolute humidity level is again determined by the control means as a function of the temperature and of the relative humidity level measured, in order, for example, to decrease the temperature of the last main cylinder (10) and / or increase the speed of the motor (20) and / or decrease the pressure exerted by the back pressure means (30).

The choice to vary such or such parameters depends on different criteria which can also be parameterized at the level of the control means. These criteria can be, for example, a maximum yield, that is to say a treatment of the greatest number of pieces of linen possible during a determined duration, and / or a minimum energy consumption, and / or a quality determined drying and ironing. These criteria are given only by way of example, equivalent criteria being able to be chosen. Similarly, changes to certain operating parameters may be subject to compliance with certain determined constraints. Thus, when the items of linen treated are, for example, made of vegetable or synthetic fibers, it is advisable to avoid subjecting them to excessive mechanical (tension, compression) or thermal stresses. The tolerable thresholds of these mechanical stresses depend not only on the nature of the parts (materials, dimensions), but also on their state at the start of treatment. To do this, the control means (50) comprise comparison means, consisting for example of a comparator circuit, for comparing the operating parameters with limit values, fixed for example, by the user. If, during the calculation of the new operating parameters, one of the parameters is greater than the limit value determined for this parameter, then all of the parameters are recalculated by the control means by setting the value of this parameter to its maximum authorized value .

The means (60) for measuring relative humidity and temperature comprise, for example, means (61, 62) for capturing the atmosphere in the immediate vicinity of the piece of linen treated downstream of the last main cylinder (10) . In an alternative embodiment (not shown) and so that the measurement is significant of the state of the laundry on the whole of the room, the measuring means (60) carry out either the integration or the average of the values of the rate relative humidity and temperature, over the entire useful length of the main roller (s). To do this, a plurality of capture means (61, 62) can be arranged along a straight line parallel to the longitudinal axis of the last main cylinder (10). Contrary to what has been proposed in the previously known embodiments, it is not desirable to place sensors near the main cylinder or cylinders or even at the level of the extraction circuit. Indeed, the cylinder being brought to high temperature (of the order of 60 to 80 ° C) its radiation will inevitably disturb the sensors. Furthermore, the scrolling of the linen can be the cause of the deterioration of these sensitive elements, all the more so since it is frequent to observe phenomena of accumulation of textile flocks at the cylinder outlet.

The collection means can be constituted by at least one tube (61), for example of small diameter, one end of which is placed in the immediate vicinity of the outlet of the last of the main rollers and above the laundry . The other end of each tube communicates with an enclosure (62). This enclosure (62) comprises a fan (63) for extraction, so as to aspirate the atmosphere present at the outlet of the last main cylinder (10) through the tube or tubes. The interior of this enclosure (62) comprises at least one humidity sensor (64) and at least one temperature sensor (65). The values of the torque {humidity, temperature}, characteristic of the atmosphere at the outlet of the last main cylinder, are transmitted, via appropriate links (51), to the control means (50) which analyze them, for example by through an appropriate electronic circuit. This information is used to regulate in real time at least two of the three parameters mentioned above and as described above.

In order to obtain a rapid modification of the heating temperature of the last main cylinder (10), that is to say to reduce the thermal inertia of this cylinder, the outer surface of this cylinder is coated with a thermal layer. insulating. This insulating layer is itself covered by a heating film or fabric controlled by the control means (50), via an appropriate connection. Thus, the drawbacks linked to the thermal inertia of the mechanical cylinders are avoided and a simplification of the maintenance operations is also obtained.

Thus, the dryer-ironer comprising at least one rotary main cylinder (10 to 12) intended for heating the laundry to be dried, means (30) for exerting a back pressure, and means (20) for driving the means of conveying the linen in the dryer-ironer, is characterized in that the dryer-ironer also comprises means (60) for measuring the absolute rate of water vapor at the outlet of the last main cylinder (10), the means (60 ) of determination being connected to control means (50) making it possible to vary, at least two from the following three operating parameters, the temperature of the last main cylinder (10), the force exerted by the counter means (30) pressure, the speed of the means (20) for driving the means for conveying the linen, as a function of the value of the relative humidity rate and of the temperature measured by the measuring means (60).

According to another particular feature, the measuring means (60) comprise means (61, 62) for capturing the atmosphere in the vicinity of the last main cylinder (10) for bringing the atmosphere to an enclosure (62) provided with at least one extractor fan (63), the enclosure (62) comprising at least one humidity sensor (64) and at least one temperature sensor (65).

According to another particularity, the capture means (61, 62) consist of at least one tube (61) of small diameter, one of the ends of which is placed in the immediate vicinity of the outlet of the last main cylinder (10), and the other end of which is placed in the enclosure (62).

In another feature, the outer surface of the cylinders (10) is coated with an insulating layer, which insulating layer is itself covered by a heating film or fabric.

• une étape de mesure de l'humidité relative et de la température de l'atmosphère régnant au voisinage de la sortie d'un dernier cylindre (10) principal d'une sécheuse-repasseuse,
• une étape de comparaison de la valeur du taux d'humidité relative mesurée avec une valeur seuil déterminée,
• une étape de modification d'au moins deux paramètres de fonctionnement de la sécheuse-repasseuse, si la valeur du taux d'humidité relative mesurée est différente de la valeur seuil déterminée, pour que la valeur de l'humidité relative à la sortie du dernier cylindre principal corresponde à la valeur seuil déterminée.

Similarly, the method of drying and ironing laundry items is characterized in that it comprises:

• a step of measuring the relative humidity and the temperature of the atmosphere prevailing in the vicinity of the outlet of a last main cylinder (10) of a dryer-ironer,
• a step of comparing the value of the measured relative humidity rate with a determined threshold value,
• a step of modifying at least two operating parameters of the dryer-ironer, if the value of the measured relative humidity rate is different from the determined threshold value, so that the value of the relative humidity at the outlet of the last main cylinder corresponds to the determined threshold value.

According to another particular feature, the two modified operating parameters are chosen from the following three operating parameters; the temperature of the last main cylinder, the speed of travel of the piece of laundry, the pressure exerted by back pressure means on the piece of laundry.

According to another particular feature, the modification is carried out as a function of the value of the absolute humidity determined from the measured values of the relative humidity rate and of the temperature.

According to another particular feature, the modification step is implemented when the value of the relative humidity rate is not between 95 and 99%.

It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments should be considered by way of illustration but may be modified in the field defined by the scope of the appended claims.

Claims (8)

1. Drying and ironing machine comprising at least one main rotary cylinder (10 to 12) intended to heat the laundry to be dried, means (30) for exerting back pressure, and means (20) for driving the means for conveying laundry items to the drying and ironing machine, characterised in that the drying and ironing machine also comprises means (60) for measuring the level of relative humidity and the temperature of the atmosphere prevailing in the vicinity of the outlet of the last main cylinder (10), in the immediate vicinity of the item of laundry that is being treated, the measurement means (60) being connected to control means (50) making it possible to vary at least two of the following three operating parameters, the temperature of the last main cylinder (10), the force exerted by the back pressure means (30), the speed of the means (20) for driving the means for conveying the laundry, as a function of the value of the control humidity level from the relative humidity level and the temperature measured by the measurement means (60).
2. Drying and ironing machine according to Claim 1, characterised in that the measurement means (60) comprise means (61, 62) for collecting the atmosphere in the vicinity of the last main cylinder (10) in order to direct the atmosphere towards an enclosure (62) provided with at least one extractor fan (63), the enclosure (62) comprising at least one humidity sensor (64) and at least one temperature sensor (65).
3. Drying and ironing machine according to Claim 2, characterised in that the collection means (61, 62) are constituted by at least one small-diameter tube (61), one of the ends of which is placed in the immediate vicinity of the outlet of the last main cylinder (10), and the other end of which is placed in the enclosure (62).
4. Drying and ironing machine according to one of Claims 1 to 3, characterised in that the outer surface of the cylinders (10) is covered with an insulating layer, which insulating layer is itself covered with a heating fabric or film.
5. Method for drying and ironing items of laundry characterised in that it comprises:

   - a step of measuring the relative humidity and temperature of the atmosphere prevailing in the vicinity of the outlet of a last main cylinder (10) of a drying and ironing machine, in the immediate vicinity of the item of laundry being treated,

   - a step of comparing the value of the level of measured relative humidity with a given threshold value,

   - a step of modifying at least two operating parameters of the drying and ironing machine, if the value of the level of measured relative humidity is different from the given threshold value, so that the value for relative humidity at the outlet of the last main cylinder corresponds to the given threshold value.
6. Method for drying and ironing items of laundry according to Claim 5 characterised in that the two modified operating parameters are chosen from among the following three operating parameters: the temperature of the last main cylinder, the speed at which the item of laundry passes, the pressure exerted by the back-pressure means on the item of laundry.
7. Method for drying and ironing items of laundry according to Claim 5 or 6, characterised in that the modification is carried out as a function of the value of absolute humidity determined from the measured values of the level of relative humidity and temperature.
8. Method for drying and ironing items of laundry according to one of Claims 5 to 7, characterised in that the modification step is used when the value of the level.of relative humidity is not between 95 and 99%.