Air drying tunnel LDT

Operating principleThe Sormac air drying tunnel was developed specifically for drying delicate leafy vegetables and for creating a low attached moisture percentage with leafy vegetables.

Before reaching the drying tunnel, the product goes through a preliminary de-watering step by means of a de-watering belt. In the drying tunnel, the product is dried in an air stream that is oriented upwards, at a temperature of 25 to 30 ºC. The air speed is such that the product will float, causing as much moisture as possible to be released.

The air stream that is in circulation is cooled down in a heat exchanger to a temperature of approx. 5 ºC. Some of the water vapour is removed from the air stream because it condenses on the cold fins of the heat exchanger.

To enable the air to absorb moisture again, it is passed through a second heat exchanger where it is warmed up to a temperature of 25 to 30 ºC, lowering its relative humidity.

While drying the product, the air cools down due to the evaporation of the surface water on the product. This effect keeps the product much cooler than the drying air.

The air is cooled down and warmed up by using a glycol solution or a similar medium of approx. 0 ºC and, respectively, 33 ºC. This medium is supplied by the client or produced using a separate cooling installation.The cooling machine can be used as a heat pump to achieve considerable energy savings.

The air drying tunnel enables moisture values of less than 2% on the surface of the product to be reached.

Product specificationThe air drying tunnel is ideally suitable for delicate leafy vegetables such as spinach and baby leaf, but also for cut iceberg lettuce, etc.

Options ■ cooling system / heat pump ■ de-watering belt ■ integrated cooling section

Sormac B.V. Alterations reservedP.O. Box 419 T +31 (0)77 351 84 44NL-5900 AK Venlo F +31 (0)77 320 48 01

Huiskensstraat 68 E info@sormac.nlNL-5916 PN Venlo I www.sormac.nl

LDT-140

230/400 V, 50/60 Hz

8.190 x 3.835 x 3.715 mm *

1,400 mm

max. 3,050 kg/uur max. 1,855 kg/uur max. 1,585 kg/uur

Type

Voltage:

Dimensions (LxWxH):

Belt width:

Capacity**:Iceberg lettuceSpinachBaby leaf

LDT-50/5D

230/400 V, 50/60 Hz

6,745 x 2,040 x 2,425 mm

500 mm

max. 600 kg/uur max. 400 kg/uur max. 350 kg/uur

LDT-100

230/400 V, 50/60 Hz

6,830 x 2,530 x 3,430 mm*

1,000 mm

max. 2,900 kg/uur max. 1,770 kg/uur max. 1,510 kg/uur

* Several configurations/lengths are available** Capacities based on 8% incoming and 1% exiting attached moisture

Technical data

Closed systemNo energy is dissipated to the environment because the drying takes place in a closed system.

Easily accessibleAll the compartments in the air drying tunnel are accessible for optimum cleaning.

Gentle product handlingThe thermal drying process minimizes any product damage. This makes the air drying tunnel excellently suited to drying delicate products.

Integrated cooling sectionThe air drying tunnel features a cooling section to cool down the product to the packaging temperature desired.

The difference is in the details...

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Fans that can be folded open (optional) The de-watering belts can be constructed with

fans that can be folded open to enable quick access for cleaning.

Drying line with two de-watering belts and an LDT-140/7 air drying tunnel. Suitable for approx. 2,600 kg/h of iceberg lettuce, 1,700 kg/h of spinach or 1,500 kg/h of baby leaf.

Sormac drying lineThe air drying tunnel is installed in a line with de-watering belt. These de-watering belts remove the excess water from the product before it enters the air drying tunnel. Depending on the capacity and the final result desired, each belt can feature two or three beaters and vacuum stations.

The drying processHot air with low relative humidity is blown through the product from below . The water on the leaf surface

evaporates as the hot drying air passes the layer of products and the temperature of the air drops because

the evaporation heat is withdrawn from the air.To keep the circulating air flow free from product, a

mesh belt has been installed over the product; this belt works like a filter. After passing the filter belt, the air is

guided through a cooler . Here, the air temperature is decreased so that a major fraction of the water vapour

condenses onto the cooling fins. The condensed water is collected in a drain and removed from the unit. A second

heat exchanger heats up the circulation air again to its initial condition (warm with low relative humidity).

It is thus ready to withdraw water from the layer of products once again as it passes through the products.

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