Industrial washing system for Euronorm containers E1 and E2, as well as H1 plastic pallets

Three-tank washing system for intensive cleaning

The DLWA 1200-3T/2+ PAL BS4H industrial washing machine is equipped with three wash tank systems and coordinated treatment zones for pre-wash, main wash and rinse.

Cold water pre-spraying takes place as early as the 1,500 mm long inlet section. At the same time, a coarse dirt removal system enables larger contaminants to be removed from the rest of the washing process at an early stage.

Pre-wash to loosen heavier soiling

The inlet is followed by a 3,600 mm long pre-wash zone. A pump with an 11 kW motor and a flow rate of up to 1,500 litres per minute at 3 bar is available for this process area. 

The pre-wash serves to intensively pre-treat adhering dirt on the Euronorm containers or H1 plastic pallets and to loosen it for the subsequent main cleaning.

Particularly in the case of heavily soiled Euronorm containers, the reduced flow rate allows the exposure and treatment time within the wash zones to be extended.

High-performance main wash

The subsequent main wash zone is 2,700 mm long. A 22 kW pump provides a flow rate of up to 2,000 litres per minute at 5 bar for this purpose. 

The nozzle and washing system is tailored to the items being washed. The stainless-steel nozzles used have a large flow orifice. To simplify cleaning and maintenance, the nozzle arms can be removed without tools. 

The combination of high circulation capacity, targeted nozzle arrangement and adjustable conveyor speed makes it possible to tailor the cleaning intensity to the specific level of soiling.

Separate rinse

After the main wash, the cleaned Euronorm containers or H1 plastic pallets pass through a 2,700 mm long rinse zone.

Here, a further pump with an 11 kW motor and a flow rate of up to 1,000 litres per minute at 5 bar is in operation. The separate rinse cycle marks the end of the wet cleaning process. 

A hot water connection is provided for the heat supply. In addition, the system features a separately switchable 10 kW boiler. A flow temperature of at least 75 °C is specified for the hot water.

Variable washing capacity of 1,200 to a maximum of 1,500 Euronorm containers per hour

The system is designed for a cleaning capacity of 1,200 to a maximum of 1,500 Euronorm containers (E1 and E2) per hour. The actual operating capacity is adjusted according to the degree of soiling of the containers.

For more heavily soiled containers, the speed of the conveyor drive is reduced via the frequency converter. As a result, the Euronorm containers remain in the individual wash zones for longer and are cleaned more thoroughly.

For containers with a moderate level of soiling, the conveyor speed can be increased, allowing a greater number of Euronorm containers to be cleaned within the same operating time.

This means the operator is not restricted to a fixed system capacity, but can adjust the washing process as required to balance cleaning intensity, treatment duration and container throughput. This provides additional flexibility, particularly when dealing with varying levels of soiling during ongoing production.

Cleaning of H1 plastic pallets

In addition to E1 and E2 Euronorm containers, H1 plastic pallets can also be cleaned within the same system.

The pallets are transported through the washing zones via a dedicated skid guide with a separate drive. The hourly throughput for H1 plastic pallets is up to 200 units.  

The combined design for Euronorm containers and pallets allows different load carriers to be cleaned within a single system concept. This reduces the need for separate cleaning systems and enables flexible adaptation to the respective production process.

Filtration technology for high container volumes and high levels of contamination

To support the washing process, the system is equipped with a TRF-DLWA I-90° drum filter system.

The rotating drum continuously separates dirt particles from the wash solution. An internal screw conveyor automatically transports the separated residues into an external collection tank. This can be easily removed for emptying.

 

This ensures that contaminants are continuously removed from the washing circuit. Particularly in the case of heavily soiled Euronorm containers and high daily container volumes, this reduces the manual effort required for filter cleaning and helps to ensure consistent treatment of the circulating washing medium.

In addition, two external filter tanks for the main wash and final rinse are integrated. These aid in the separation of dirt, particularly when handling high container volumes and heavily soiled containers.

The filter tanks are made of 3 mm-thick stainless steel and feature access holes, funnel-shaped overflows and rounded, smoothly ground inner edges. They are therefore designed for robust industrial use and to ensure the simplest possible cleaning.

Blow-dry system with four high-pressure fans

Once the washing process is complete, the cleaned Euronorm containers are fed into a high-performance blow-dry system.

The blow-dry tunnel has a total length of 3,700 mm and is equipped with four ELEKTROR high-pressure fans, each with a motor output of 5 kW. 

The precisely directed airflow removes the majority of the water remaining on the surfaces. This significantly reduces the residual moisture in the cleaned Euronorm containers whilst they are still passing through the continuous process.

For new Euronorm E2 containers, the documented residual moisture after blow-drying is approximately 8 to 12 grams per container. 

The actual drying result achievable may be influenced, amongst other things, by the condition, geometry and surface finish of the Euronorm containers.

Vapour extraction with reduced heat loss

The cleaning process generates moist, warm air, which must be extracted from the system in a controlled manner. Two extraction points are provided for this purpose: one in the inlet area and another at the start of the blow-off drying stage.

The extraction system is deliberately designed not to operate directly within the active main cleaning zone. If the air were extracted directly from this area, heat – which is required to maintain the temperature during the cleaning process – would be lost along with the vapour.

Instead, the design utilises the slight positive pressure inside the machine. The vapour escaping at the designated points as a result is specifically captured and extracted via the extraction system. The humid air is thus collected where it would escape from the tunnel anyway, without unnecessarily drawing off the warm process atmosphere in the main cleaning section.

Prepared for subsequent label removal

In the case of Euronorm containers, adhering labels and label residues – particularly during long-term use – can place additional demands on the cleaning process.

The washing system has therefore been designed in such a way that a label-removal function can be retrofitted at a later date. A corresponding screw-type flange connection has already been provided for this purpose. 

This ensures that the system remains expandable to meet future requirements without necessitating any fundamental design changes to the washing machine should it be upgraded at a later date.

Conveyor systems for further material flow

After cleaning and blow-drying, the Euronorm containers and H1 plastic pallets are transported further via the connected conveyor system.

The system includes a return conveyor on the line, partly with its own drive, as well as a 90° bend followed by a 6-metre-long outfeed conveyor. 

This allows cleaning, drying and onward transport to be integrated within a continuous in-house material flow.

Robust construction and low-maintenance design

The washing system is designed to meet the demands of industrial use.

The upper section of the machine is double-walled and insulated, manufactured as a single piece and fully welded. The wash tunnels, tailored to the specific items being washed, together with the nozzle and wash system, ensure intensive and uniform treatment of Euronorm containers and H1 plastic pallets. 

Nozzle arms that can be removed without tools simplify regular cleaning and maintenance. Key system components include drive and frequency converter technology from LENZE, stainless steel centrifugal pumps from EDUR and control cabinet components from SIEMENS.