FR3091301A1 - Washing system for industrial laundry - Google Patents

Abstract

A washing system for an industrial laundry comprises a washing line (12) and a washing water heating unit (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) fixedly mounted and forming a sealed conduit extending into the tank (24) to be, in use, immersed in the washing water to be heated. Means are provided for supplying hot gas to the heating pipe, in particular a burner (32) associated with a fan (40) able to push the hot gas into the heating pipe (30). Figure to be published with abstract: Figure 1

Description

Description

Title of the invention: Washing system for industrial laundry

Technical area

The present invention generally relates to the field of industrial laundry and industrial laundry washing systems. The present invention relates more particularly to systems comprising a washing machine tunnel and a washing water heating unit.

State of the art

Washing tunnels are mainly used in laundries or for washing large quantities of laundry. These are large installations comprising a fixed tank in which there is a drum which can be rotated selectively. The drum is divided lengthwise into successive compartments each capable of holding a load of laundry. Each compartment corresponds to a determined washing step such as for example a prewash, a washing or a rinsing.

A load of laundry passes successively in one or more prewash compartments, in at least two washing compartments and in one or more rinsing compartments, before leaving the tunnel.

In the prewash and washing compartments, the laundry is immersed in water containing cleaning products. A washing compartment is therefore equipped with an inlet and 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 should be possible to heat the washing bath from 40 ° C to 65 ° C in around thirty seconds.

Heating water requires special systems capable of heating a large amount of water for a very short time. In addition, heating the washing water is technically complex because it is water loaded with detergents and suspended matter such as dirt or lint in the laundry, with a strongly basic PH .

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

Customer demand is high for eliminating high-pressure steam boilers from their laundry. So-called steamless technology in washing tunnels is therefore being developed in the industrial laundry sector.

There is known a steamless washing system marketed by the company Ecolab (Wallisellen, Switzerland). The system includes 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 up to 115 microns thanks to an all-in-one disc filtration device. The 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 washing bath through the filter, then through the generator.

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

Document EP 2 177 659 B1 presents another solution for heating washing water without steam for a washing machine tunnel. The system comprises a heat exchanger, the primary circuit of which is connected to a heating circuit of a pressurized heating fluid, and the secondary circuit of which is connected to the washing water circuit in communication with a compartment of the washing tunnel. The primary circuit heating fluid passes through a rotary hollow shaft arranged in a tank containing the washing water to be heated.

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

Although this solution is technically satisfied, it has a certain cost linked to the design of the exchanger with a rotary 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 prior art. General description of the invention

According to the present invention, a washing system for industrial laundry comprises a washing line with a plurality of washing chambers in series to perform a washing with water of linen introduced into the line. The washing water is introduced into the washing line through an inlet and leaves 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 outlet for washing water from the line. and a second pipe connected to the line washing water inlet.

The heating unit includes:

- 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 heating tube mounted fixed and forming a sealed conduit extending in 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 includes laundry cleaning products, such as detergents and / or softeners, and which gradually becomes soiled and fluff from the laundry, suspended in water. The wash water is therefore dirty water, and its pH is around 10.

The invention relates to a washing system comprising a washing water heating unit of the indirect type. Indeed, the primary heat source is not in direct contact with the wash water, but the heating tubing forms a gas-water heat exchanger, which allows the passage of calories from the hot gas to the water of 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. Initial tests have shown that, surprisingly, there are no problems associated with deposits on the heating manifold. The system operates nominally in the absence of elements for filtering the wash water. The washing water being in the tank at atmospheric pressure, there are no problematic clogging effects as in pressurized heaters. Dirt and particles carried by the washing water tend to settle at the bottom of the tank. Periodic cleaning of the tank, e.g. once a month is sufficient. In addition, the system according to the invention makes it possible to quickly heat the washing water, 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 from 30 s.

The heat exchanger constituted by the heating tube 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 on the cost of installation and also in maintenance. The tubing is typically made of a heat conductive and corrosion resistant material. Stainless steel is suitable, especially 316 stainless steel.

Advantageously, the supply means comprise a burner associated with a fan capable of pushing the hot gas into the heating manifold. The burner is for example placed in a chamber supplied with air forced 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 upstream of the burner and the quantity adapted to the heating power of the burner, which can be variable. The term fan is used here generically and covers any means capable of pushing air into the system, in front of the burner and in the heating manifold, 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 manifold 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 driving; and in an outlet zone with the outlet connected to the second pipe, the washing water passing by overflowing from the heating area to the outlet area.

According to the variants, the heating tube 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 pipe, 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 a temperature control in a closed loop. 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 sensors 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:

[Fig.l] a block diagram of the present washing system;

[Fig.2] a perspective view of the heating unit according to one embodiment;

[Fig.3] a perspective view from above of the heating unit of Figure 2;

[Fig.4] a top view of the heating unit of Figure 2; and [Fig.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 heating unit 14, intended to heat and / or heat the washing water used in the washing line 12.

The washing line 12, also called washing tunnel, allows washing large quantities of laundry continuously. This tunnel 12 can be integrated as a modular element in a larger washing chain 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. The laundry is introduced at an inlet 16 of the tunnel 12 into a drum, not shown, which is subdivided into various laundry treatment areas by internal partitions. The treatment zones, or washing chambers, are indicated in 18.1 to 18.6. The drum is equipped with conveyors intended to circulate the linen through all the planned treatment zones, to carry out a complete washing cycle. The treatment zones comprise for example two prewash 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. The washing water is water heated to a predetermined temperature, for example between 40 ° C and 65 ° C. To reduce the water consumption of the system, the water is reused for several washing or prewash cycles. According to the cycles and the quantity of linen present in a compartment of the tunnel, the water is evacuated from the tunnel to the heating unit 14, in order to be heated there to a predetermined temperature, before being returned to the tunnel 12 .

During these washing water transfer operations, it is loaded with fluff and dirt from the laundry. In addition, the water contains cleaning products which gives it a strong basicity with a pH of around 10.

In FIG. 1, there is a hot water supply line 20 and a return line 22, which are for example respectively coupled to the prewash 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 23.0η will understand that the tunnel may include a more complex supply and discharge circuit 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 washing 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 washing water in the tank 24 is produced by means of a heating tube 30 fixedly mounted and extending in the tank 24 so as to be, in use, immersed in the washing water to be heated. The heating tubing can generally be a cylindrical tube or pipe made of heat-conductive material, preferably a corrosion-resistant metal (eg stainless steel, in particular stainless steel 316), which forms a tight conduit snaking in the tank. The two open ends of the conduit form the inlet and outlet of the tubing. Means are provided for circulating inside the pipe 30 hot gases. 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 line 42 which is connected to a bottle or to the network (not shown). The heating pipe 30 has an outlet 44 which is connected to a gas evacuation duct 46.

In the present system, the washing water residing in the tank 24 is thus heated by means of hot gases circulating in the heating tube 30 immersed in the washing water, and describing meanders, generally in the manner of a serpentine. The fan 40 pushes the air into the burner chamber 34 and further into the heating pipe 30. The amount of air is adapted relative to the desired power for the burner 32. Depending on the operating conditions, the hot gas which leaves the chamber 34 and is pushed into the heating pipe 30 thus comprises the combustion gases and a variable quantity 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 washing 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 by the inlet 36 in the heating zone 50, in which the heating tubing 30 extends. In general, the heating tubing 30 must be completely immersed in the washing water. It therefore extends 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 above the wall 48, to be evacuated by the outlet 28.

The heating unit 14 is simple and efficient in 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 immersed 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 the device 10 to function properly. 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 around 70 ° C over a period of 30 s. For example, on a washing water exchange cycle between the tunnel and the heating unit which lasts approximately 120 s, the burner is thus in operation 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, e.g. 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 includes a heating control module, for example. PID type, to control the heating of the burner 32 according to a desired set temperature. It also includes means of communication with the user, such as, for example. a touch screen or not, keyboard and / or buttons and / or adjustment sliders.

The housing 54 can be independent of the control unit of the washing tunnel, or integrated therein.

We will now describe a variant construction of the heating unit 14 shown in Figures 2 to 5.

The heating unit comprises a tub 24 of rectangular base washing water for receiving the washing 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 the inlet opening 36 of the heating pipe 30 and a burner port 66 are connected. The heating chamber is supplied with air by the air intake manifold 38, which here comprises the fan 40, a filter

68, and a flow meter 70 downstream of the fan 40. The flow meter 70 makes it easy to measure the flow of forced air pushed into the heating 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 connection cone 74, at the end of which is connected the opening of entry 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 tube 30 comprises a plurality of loops 76, thus forming a coil in the heating zone 50 of the tank 24, and comes out of the tank 24 at an outlet which passes through the transverse wall 60.1. In practice, for a 500 L tank of water, heating tubing 30 can 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 sheath (not shown). The air is then recycled or evacuated to the ambient environment.

The temperature of the gases decreases when they pass through the tube 30. The tube 30 can have a wall temperature of the order of 200 ° C on the side of the inlet 36, to reach about 90 ° C towards the exit 44.

Note that the heating tube 30 extends in 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 line 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 area 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 for supplying 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 bottom 58 of the heating zone 50. The overflow wall 48 increases the residence time of the water in the tank, because the water cannot pass in the outlet zone only by overflowing above the upper edge of the wall 48. In the heating zone, the water arriving from the tunnel is heated by the coil 30, and rises in the tank due to the difference density with cold water. The heated wash water therefore overflows into the outlet zone from where it is discharged through the outlet pipe 78. The pump 56 can control the discharge of the wash water on request. Note that the pump 56 is not required, it is also possible to transfer by gravity the heated water to the tunnel 12.

In principle, water is sent from the tunnel to the heating unit when the washing water has to be heated. Depending on the configuration, this can be done continuously or not, by gravity or using pumps. The washing water circuit being closed, the transfer of water 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 is actuated in opening and closing by a pneumatic motor 84 to perform a drain automatically.

The tank 24 also includes an overflow opening 86 which makes it possible to discharge the washing water into an overflow line 88 communicating with a sewer, not shown, in the case where the washing water exceeds a height overflow in the tank. The overflow pipe 88 is connected at the bottom of the tank to a manual drain pipe 90 fitted with a manual valve.

The tank 24 also includes two pipes which allow the tank 24 to be filled with clean water.

A low pipe 98 of clean water allows filling of the tank if necessary, such as after cleaning the tank 24. The low pipe 98 is mounted through the transverse wall 60.1 at the bottom 58 of the tank 24.

A high pipe 100 of clean water allows the cleaning of the tank 24. The high pipe 100 is mounted through the transverse wall 60.1 at a level above the coil 30. The high pipe 100 extends to the inside of the tank 24 in a straight washing hose 102 which comprises two cleaning balls 104. The cleaning balls 104 are balls perforated with multiple holes to project the pressurized water into the whole of the tank 24.

The two clean water pipes 98, 100 are connected to the same clean water inlet pipe. Each pipe however has a manual valve 106, 108 respectively for opening and closing the supply of clean water.

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.

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

A tubing level sensor 94 indicates that the washing water is at the high level of the overflow wall 48. When the washing water reaches the level of the tubing sensor, the tubing is fully submerged. To avoid overheating and possible deterioration of the heating coil, it is permanently immersed in the washing water, outside the tank emptying and cleaning periods. It is also a minimum function level for the heating unit.

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

Claims (1)

Claims [Claim 1] Washing system for industrial laundry comprising: a washing line (12) with a plurality of washing chambers (18.i) in series, the washing line having at least one inlet (21) and one outlet (23) for washing water, a heating unit (14) of washing water 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 line (20) connected to the inlet water washing line; 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 tube (30) fixedly mounted 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. [Claim 2] The system of claim 1, wherein said means comprises a burner (32) associated with a fan (40) capable of pushing the hot gas into the heating manifold (30). [Claim 3] System according to claim 2, in which said burner (32) is placed in a chamber (34) supplied with air forced by the fan (40) and in communication with the inlet opening (36) of the heating pipe ( 30), so that the hot gas pushed into the heating pipe comprises hot air and / or combustion gases. [Claim 4] A system according to any one of the preceding claims, comprising an air intake manifold (38) upstream of the burner, with said fan, an air filter (40) and a flow meter (70). [Claim 5] System according to any one of the preceding claims, in which the tank (24) comprises an overflow wall (48) extending from the bottom of the tank to a predetermined height, and dividing the tank into a heating zone ( 50) with said heating pipe (32) and said inlet (26) connected to said first pipe (22), and in an outlet zone (52) with said outlet (28) connected to said second pipe (20), l wash water passing by overflowing from the heating zone to the outlet zone. [Claim 6] System according to the preceding claim, in which the heating pipe (30) is arranged so as to describe meanders in the tank (24), between the bottom of the tank and a height less than said predetermined height of the overflow wall ( 48). [Claim 7] A system according to any one of the preceding claims, wherein the interior of the tank (24) is at atmospheric pressure. [Claim 8] System according to any one of the preceding claims, comprising an electronic control unit (54) associated with at least one temperature probe installed in the tank. [Claim 9] System according to any one of the preceding claims, comprising a cleaning pipe (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. 1/3