LU101076B1 - Washing system for industrial laundry - Google Patents

Abstract

A washing system for industrial laundry comprises a washing line (12) and a washing water heater (14), separated from the washing line, and connected thereto by pipes (20, 22 ). The heating unit comprises a tank (24) at atmospheric pressure for the washing water to be heated, and a heating pipe (30) mounted fixed and forming a sealed duct extending into the tank (24) to be, in use, immersed in the washing water to be heated. Means are provided for supplying the heating pipe with hot gas, in particular a burner (32) associated with a fan (40) capable of pushing the hot gas into the heating pipe (30).

Description

Washing System for Industrial Laundry Technical Field The present invention relates generally to the field of industrial laundry and industrial laundry washing systems.

The present invention relates more particularly to systems comprising a washing tunnel for washing clothes and a unit for heating the washing water.

STATE OF THE ART Washing tunnels are mainly used in laundry installations or for washing large quantities of laundry.

These are large-scale installations comprising a fixed tank in which there is a drum which can be selectively rotated.

The drum is divided, in the direction of its length, into successive compartments each capable of containing a load of laundry.

Each compartment corresponds to a determined washing step such as for example a prewash, a wash or a rinse.

A load of laundry passes successively through one or more pre-wash compartments, at least two washing compartments and one or more rinsing compartments, before exiting the tunnel.

In the pre-wash and wash compartments, the laundry is immersed in water containing cleaning products.

A washing compartment is therefore equipped with an inlet and an outlet for washing water.

This water is used in a closed circuit: it is initially heated to the desired temperature by a heating system outside the tunnel, then sent into the tunnel.

It is then cyclically returned to the heating system to be reheated and then reintroduced into the tunnel.

Generally, at each cycle, it is necessary to be able to heat the wash bath from 40 ° C to 65 ° C in about 30 seconds.

Heating water requires special systems capable of heating a large quantity of water for a very short time.

In addition, heating the laundry washing water is technically complex because it is water loaded with detergents and suspended matter such as dirt or lint found in the laundry, with a strongly basic pH.

Conventional heating systems use steam water heaters, which are not energy efficient and present the risk of explosion.

Customer demand is strong to eliminate high pressure steam boilers from their laundry. The so-called steamless technology in washing tunnels is therefore under development in the industrial laundry sector.

We know a washing system without steam marketed by the company Ecolab (Wallisellen, Switzerland). The system comprises a gas boiler which directly heats the water coming from the washing tunnel. Upstream of the boiler, the system includes a filter (Aquacycler model) to filter the process water down to 115 microns using an all-in-one disc filtration device. Filtered water is ready to be reused at a temperature between 25 ° C and 40 ° C (depending on the washing process), saving water and electricity. A pump circulates the water from the wash bath through the filter and then into the generator.

However, this system has drawbacks. The filter is a high-tech element which has a high cost compared to the whole system. In addition, the wash water at a pH of about 10 which causes a slow destruction of the heating body of the boiler generator heated to about 65-70 ° C.

EP 2 177 659 B1 discloses another steamless wash water heating solution for a laundry tunnel. The system comprises a heat exchanger, the primary circuit of which is connected to a heating circuit of a heating fluid under pressure, and the secondary circuit of which is connected to the washing water circuit in communication with a compartment of the washing tunnel. The heating fluid of the primary circuit passes through a rotating hollow shaft arranged in a tank containing the washing water to be heated.

In this system, the water in the tunnel is heated indirectly without the water in the washing tunnel coming into contact with a high temperature heating element. In addition, the use of a rotating hollow shaft for the primary circuit prevents the deposit of dirt from the washing water in the heat exchanger.

Although this solution is technically satisfactory, it has a certain cost associated with the design of the exchanger with a rotating shaft.

Object of the invention The object of the present invention is to provide an improved solution for a washing water heating system in a washing installation, which does not include the known drawbacks of the systems of the state of the art.

General Description of the Invention In accordance with the present invention, a washing system for industrial laundry comprises a washing line with a plurality of washing chambers in series for performing water washing of laundry fed into the line. The washing water is introduced into the washing line through an inlet, and comes out at an outlet.

A washing water heating unit at atmospheric pressure is provided, separated from the washing line, and connected to the latter by means of a first pipe connected to the washing water outlet of the line and a second pipe connected to the washing water inlet of the line.

The heating unit comprises: - a tank for the washing water to be heated, comprising an inlet connected to said first pipe and an outlet connected to said second pipe; - a fixed mounted heating pipe forming a sealed conduit extending into the tank to be in contact with the washing water to be heated;

- Means for supplying hot gas to an inlet opening of the heating pipe.

In the context of the invention, the washing water is water which is used in a closed circuit during one or more washing cycles.

The washing water comprises products for cleaning the laundry, such as, for example, detergents and / or softeners, and which gradually becomes loaded with dirt and lint from the laundry, suspended in the water.

The washing water is therefore dirty water, and its pH is about 10. The invention relates to a washing system comprising a washing water heating unit of the indirect type.

In fact, the primary heat source is not in direct contact with the washing water, but the heating pipe forms a gas - water heat exchanger, which allows the passage of calories from the hot gas to the water. washing to heat.

A notable advantage of the invention is the simple and efficient design of the heating unit, which therefore does not use a traditional heating body and does not require a pressurized water circuit or filtration devices.

First tests have shown that, surprisingly, there is no problem associated with deposits on the heating pipe.

The system operates nominally in the absence of wash water filtration elements.

The washing water being in the tank at atmospheric pressure, there are no problematic clogging effects as in pressurized heating bodies.

Dirt and particles carried by the wash water tend to settle to the bottom of the tank.

Periodic cleaning of the tank, eg. once a month is sufficient.

In addition, the system according to the invention enables the washing water to be heated rapidly, in particular to bring it to temperatures of the order of 40 to 65 ° C over a period of less than 60 s, and in particular of the order of 30 s.

The heat exchanger formed by the heating pipe is immersed in the washing water residing in the tank, which is at atmospheric pressure.

Compared to conventional systems, there is no longer a pressurized primary hot water circuit.

The elimination of the primary circuit and the filter saves the cost of the installation and also in maintenance.

The tubing is typically made of a heat conducting and corrosion resistant material.

Stainless steel is suitable, in particular 316 stainless steel. Advantageously, the supply means comprise a burner associated with a fan capable of pushing the hot gas into the heating pipe.

The burner is for example placed in a chamber supplied with air pulsed by the fan and in communication with the inlet opening of the heating pipe, so that the hot gas pushed into the heating pipe comprises hot air. and / or combustion gases.

The burner is supplied with fuel, typically gas.

The air is drawn in upstream of the burner and the quantity is adapted to the heating power of the burner, which can be variable.

The term fan is used generically here and covers any means capable of pushing air into the system, in front of the burner and into the heating pipe, whether it is a fan, a turbine or other equivalent equipment.

Preferably, the fan, an air filter and a flow meter are placed in an intake pipe upstream of the burner.

According to the variants, the tank comprises an overflow wall extending from the bottom of the tank to a predetermined height, and dividing the tank into a heating zone with the heating pipe and the inlet connected to the first pipe; and in an outlet zone with the outlet connected to the second pipe, the wash water flowing overflow from the heating zone to the outlet zone.

According to the variants, the heating pipe is arranged so as to describe meanders in the tank and extends vertically between the bottom of the tank and a height less than that of the overflow wall.

According to the variants, a cleaning line, controlled by an associated valve, extends in the upper part of the tank and is configured for the projection of jets of clean water into the tank.

The system advantageously comprises an electronic control unit associated with at least one temperature probe, in order to operate closed-loop temperature control. The probe is for example installed in the tank to be in contact with the upper part of the water in the heating zone. The electronic control unit can be combined with other temperature probes in the tank or in the tunnel, and with level sensors to trigger safety procedures.

Detailed description using the figures Other features and characteristics of the invention will emerge from the detailed description of at least one advantageous embodiment presented below, by way of illustration, with reference to the accompanying drawings. These show: Figure 1: a block diagram of the present washing system; Figure 2: a perspective view of the heating unit according to one embodiment; Figure 3: a perspective view from above of the heating unit of Figure 2; Figure 4: a top view of the heating unit of Figure 2; and Figure 5: a sectional view of the heating unit along a plane perpendicular to a longitudinal wall of the tank passing through the overflow opening.

Figure 1 is a block diagram of the present washing system 10 which comprises a washing line 12 and an associated heater 14, for heating and / or reheating the washing water used in the washing line 12.

The washing line 12, also called the washing tunnel, allows the washing of large quantities of laundry continuously. This tunnel 12 can be integrated as a modular element in a larger washing line comprising, for example, other washing tunnels. The configuration of a washing tunnel is known from the state of the art and is not the subject of the invention; tunnel 12 will therefore only be briefly described. Laundry is introduced at an entrance 16 of tunnel 12 into a drum, not shown, which is subdivided into various laundry processing zones by interior partitions.

Treatment areas, or wash chambers, are shown 18.1 to 18.6.

The drum is equipped with conveyors intended to circulate the laundry through all the treatment areas provided, to achieve a complete washing cycle. The treatment zones comprise for example two pre-washing chambers 18.1 and 18.2, two washing chambers 18.3 and 18.4, a rinsing chamber 18.5 and a final washing chamber 18.6 forming a neutralization chamber.

The tunnel 12 is supplied with washing water for the laundry. Wash water is water heated to a predetermined temperature, for example between 40 ° C and 65 ° C. To reduce system water consumption, water is reused for multiple wash or prewash cycles. Depending on the cycles and the quantity of laundry present in a tunnel compartment, the water is evacuated from the tunnel to the heating unit 14, so as to be reheated there to a predetermined temperature, before being returned to the tunnel 12.

During these wash water transfer operations, the latter is loaded with lint and dirt from the laundry. In addition, the water contains cleaning products which give it a strong basicity with a pH of around 10. In FIG. 1, there is a hot water supply pipe 20 and a return pipe 22, which are for example respectively coupled to the pre-washing and washing chambers 18.1-18.4. Line 20 is connected to a hot water inlet 21 of the tunnel, while line 22 is connected to a washing water outlet 23. It will be understood that the tunnel can include a more complex supply and water circuit. evacuation of water to the heating unit 14, such as, for example, liquid inlet and outlet pipes for each treatment zone.

The heating unit 14 comprises a tank 24 for the wash water to be heated comprising an inlet 26 connected to the return line 22 and an outlet 28 connected to the supply line 20. The heating of the wash water in the tub 24 is achieved by means of a heater tubing 30 mounted fixed and extending into the tub 24 to be, in use, immersed in the wash water to be heated. The heater tubing can generally be a tube or cylindrical pipe made of a heat-conducting material, preferably a corrosion-resistant metal (e.g.

STAINLESS STEEL, especially 316 stainless steel), which forms a sealed duct winding through the tank.

The two open ends of the conduit form the inlet and outlet of the tubing.

Means are provided for circulating hot gases inside the pipe 30.

According to a variant, a burner 32 is arranged in a burner chamber 34 penetrating inside the tank 24, and the heating pipe 30 has its inlet opening 36 in this chamber 34. The reference sign 38 designates a air intake manifold comprising a fan 40, which opens into the chamber 34. The burner 32 is supplied with fuel, in particular gas, by a pipe 42 which is connected to a bottle or to the network (not shown). The heater tubing 30 has an outlet 44 which is connected to a gas discharge duct 46. In the present system, the wash water residing in the tank 24 is thus heated by means of the hot gases circulating in the gas outlet. heater 30 immersed in the washing water, and meandering, generally in the manner of a coil.

The fan 40 makes it possible to push the air into the burner chamber 34 and further into the heating pipe 30. The quantity of air is adapted in relation to the power desired for the burner 32. Depending on the operating conditions, the Hot gas which leaves the chamber 34 and is pushed into the heater pipe 30 thus comprises the combustion gases and a variable amount of hot air.

Note that the tank is a simple container, generally with metal walls, which does not need to be sealed, and is therefore typically at atmospheric pressure.

The wash water is therefore not pressurized, which avoids the clogging problems encountered with such systems.

In order to increase the residence time of the washing water in the tank 24, an overflow wall 48 divides the tank into a heating zone 50 and an outlet zone 52. The water to be heated arrives through the inlet. 36 in the heating zone 50, in which the heating pipe 30 extends. In general, the heating pipe 30 should be completely submerged in the washing water. It therefore extends in meanders between the bottom of the tank and a height which does not exceed the height of the overflow wall 48. The washing water from the heating zone 50 passes into the outlet zone 52 by overflow at the bottom. -above the wall 48, to be discharged through the outlet 28.

The heating unit 14 is of simple and efficient design. For the heat source, a simple burner combined with a fan is used, like a forced air heater. There is no primary circuit, because the hot fluid is mainly the combustion gas which circulates in the heat exchanger formed by the heating pipe 30. Finally, the heating pipe 30 is bathed in the washing water. , it is therefore not necessary to circulate the washing water in a heating body. It has also been found, surprisingly, that filtering systems are not required for proper operation of the device 10. Tests have shown that the present system makes it possible to bring a volume of 200 to 500 L of water initially to 40 ° C at a temperature of about 70 ° C over a period of 30s. For example, on a washing water exchange cycle between the tunnel and the heating unit which lasts approximately 120 s, the burner is thus operated for approximately 30 s. While the water remains in the heating zone 50, as the tank is not pressurized, the dirt and particles carried by the washing water tend to settle at the bottom of the tank. Periodic cleaning of the tank, eg. once a month, removes these deposits.

The reference sign 54 designates an electronic control unit configured to control the heating unit 14. It is connected to temperature sensors placed in the tank 24 as well as in the washing tunnel. It also controls a pump 56 placed in the return line 22. The electronic control unit 54 comprises a heating control module, eg. PID type, to control the heating of the burner 32 according to a desired setpoint temperature. It further comprises means of communication with the user, such for example. a touch screen or not, keyboard and / or adjustment buttons and / or sliders.

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The box 54 may be independent of the control unit of the washing tunnel, or integrated into the latter. We will now describe an alternative construction of the heating unit 14 shown in Figures 2 to 5.

The heating unit includes a rectangular base wash water tank 24 for receiving wash water. The tank 24 comprises a bottom 58, two transverse walls 60.1, 60.2, two longitudinal walls 62.1, 62.2 and a removable cover 64 visible in FIG. 5.

The transverse wall 60.1 comprises an opening which is closed in a sealed manner by the burner chamber 34 to which are connected the inlet opening 36 of the heating pipe 30 and a burner port 66. The heating chamber is supplied with air through the air intake pipe 38, which here comprises the fan 40, a filter 68, and a flowmeter 70 downstream of the fan 40. The flowmeter 70 makes it easy to measure the flow of forced air pushed into the chamber 30. Inside the tank 24, the heating chamber 34 or burner chamber comprises a cylinder 72 of large diameter which is extended by a connecting cone 74, at the end of which is connected the opening d The inlet of the heating pipe 30 of smaller diameter than the cylinder 72. In practice, the burner is placed so that the flame propagates in the longitudinal direction of the chamber, therefore in the direction of the cone. The heating pipe 30 comprises a plurality of loops 76, thus forming a coil in the heating zone 50 of the tank 24, and emerges from the tank 24 at an outlet which passes through the transverse wall 60.1. In practice, for a tank of 500 L of water, heating pipe 30 may have a diameter of 5 to 10 cm and a length of several meters, for example 6 to 10 m. The outlet is connected to an elbow 77, which is connected to a duct (not shown). The air is then recycled or exhausted to the ambient environment. The temperature of the gases decreases as they pass through tubing 30. Tubing 30 can have a wall temperature of around 200 ° C on the side of inlet 36, reaching about 90 ° C towards outlet 44.

Note that the heating pipe 30 extends into the heating zone 50 over a predetermined height. This height is less than the height of the overflow wall 48 which divides the tank 24 between the heating zone 50 and the outlet zone 52.

The longitudinal wall 62.1 of the tank comprises the inlet 26 for washing water connected to the water supply pipe 20. The inlet 26 opens into the heating zone 50 of the tank at the bottom 58.

The longitudinal wall tank 62.1 also includes the outlet 28 for washing water which is located in the outlet zone 52 on the other side of the overflow wall 48. The outlet 28 is here connected by an outlet pipe 78 to a pump 56 making it possible to supply the return line 22. It is noted that a manual valve 80 is connected to the pump 56 and is used in the event of maintenance of the latter.

The washing water enters the tank 24 at the level of the bottom 58 of the heating zone 50. The overflow wall 48 increases the residence time of the water in the tank, because water cannot pass through the zone. outlet only by overflow above the upper edge of the wall 48. In the heating zone, the water coming from the tunnel is heated by the coil 30, and rises in the tank due to the difference in density with cold water. The heated washing water therefore flows by overflow into the outlet zone from where it is discharged through the outlet pipe 78. The pump 56 can control the discharge of the washing water on demand. Note that pump 56 is not required, it is also possible to transfer the heated water by gravity to tunnel 12.

In principle, water is sent from the tunnel to the heating unit when the wash water needs to be heated. Depending on the configuration, this can be done continuously or not, by gravity or using pumps. With the washing water circuit closed, the water transfer between the heating unit and the tunnel takes place at substantially constant levels.

The tank further comprises means for performing emptying operations. Thus, the longitudinal wall 62.1 is crossed by an automatic drain pipe 82 which comprises a valve which is actuated in opening and closing by a pneumatic motor 84 in order to perform an automatic drain. The tank 24 also includes an overflow opening 86 which allows the washing water to be discharged into an overflow pipe 88 communicating with a sewer, not shown, in the event that the washing water exceeds an overflow height. in the tank. The overflow line 88 is connected at the bottom of the tank to a manual drain line 90 equipped with a manual valve. The tank 24 also comprises two pipes which make it possible to fill the tank 24 with clean water. A lower pipe 98 of clean water allows the tank to be filled if necessary, such as for example after cleaning the tank 24. The lower pipe 98 is mounted through the transverse wall 60.1 at the level of the bottom 58 of the tank. 24. | A high pipe 100 of clean water allows cleaning of the tank 24. The upper pipe 100 is mounted through the transverse wall 60.1 at a level above the coil 30. The upper pipe 100 extends inside the tank. tank 24 into a rectilinear washing pipe 102 which includes two cleaning balls 104. The cleaning balls 104 are perforated balls with multiple holes for projecting pressurized water throughout the tank 24. The two pipes d clean water 98, 100 are connected to the same clean water inlet pipe. However, each pipe has a respective manual valve 106, 108 for opening and closing the clean water supply. The reference sign 101 indicates an orifice for a temperature probe connected to the electronic control unit 54. The level of the tank 24 is measured using three level sensors 92, 94, 96 mounted in the transverse wall 60.1. The sensors are connected to the electronic control unit 54.

NOT

A low level sensor 92 makes it possible to indicate whether the tank is emptied.

A tubing level sensor 94 indicates that the wash water is at the top of the overflow wall 48. When the wash water reaches the level of the tubing sensor, the tubing is fully submerged. To avoid overheating and potential deterioration of the heating coil, it is permanently immersed in the washing water, apart from the draining and cleaning periods of the tank. This is also a minimum function level for the heating unit.

Finally, a high level sensor 96 indicates whether the wash water reaches the level of the overflow opening 86.

Claims (9)

Claims 1. Washing system for industrial laundry comprising: a washing line (12) with a plurality of washing chambers (18.1) in series, the washing line having at least one inlet (21) and one outlet (23) of. washing water, a unit for heating washing water (14) at atmospheric pressure, separated from the washing line, and connected to the latter by means of a first pipe (22) connected to the water outlet washing line and a second pipe (20) connected to the line washing water inlet; said heating unit comprising: - a tank (24) for the washing water to be heated, comprising an inlet (26) connected to said first pipe (22) and an outlet (28) connected to said second pipe (20); - a heating pipe (30) mounted fixed and forming a sealed conduit extending into the tank (24) to be, in use, immersed in the washing water to be heated; - Means for supplying hot gas to the heating pipe. 2. System according to claim 1, wherein said means comprise a burner (32) associated with a fan (40) capable of pushing the hot gas into the heating pipe (30). 3. System according to claim 2, wherein said burner (32) is placed in a chamber (34) supplied with forced air by the fan (40) and in communication with the inlet opening (36) of the manifold. heater (30), so that the hot gas pushed into the heater pipe comprises hot air and / or combustion gases. 4. System according to any one of the preceding claims, comprising an air inlet pipe (38) upstream of the burner, with | said fan, an air filter (40) and a flow meter (70). | 5. System according to any one of the preceding claims, wherein the vessel (24) comprises an overflow wall (48) extending from the bottom of the vessel to a predetermined height, and dividing the vessel into a zone of. heater (50) with said heater tubing (32) and said inlet (26) connected to said first duct (22), and in an outlet zone (52) with said outlet (28) connected to said second duct (20) , the wash water flowing from the heating zone to the outlet zone. 6. System according to the preceding claim, wherein the heating pipe (30) is arranged so as to meander in the tank (24), between the bottom of the tank and a height less than said predetermined height of the wall of overflow (48). 7. System according to any one of the preceding claims, wherein the interior of the vessel (24) is at atmospheric pressure. 8. System according to any one of the preceding claims, comprising an electronic control unit (54) associated with at least one temperature sensor installed in the tank. 9. System according to any one of the preceding claims, comprising a cleaning line (102), controlled by an associated valve, extending in the upper part of the tank and configured for the projection of jets of clean water into the tank.