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Subject to changesSormac Inc.
6800 Wales Rd.Northwood, OH 43619P.O. Box 60340Rossford, OH 43460
Office: +1 (567) [email protected]
Air drying tunnel LDT
Operating principleThe Sormac air drying tunnel was developed specifically for drying delicate leafy vegetables and for creating a low remaining moisture percentage with leafy vegetables.
Before reaching the drying tunnel, the product goes through a preliminary dewatering step by means of a dewatering belt. In the drying tunnel, the product is dried in an air stream that is oriented upwards, at a temperature of 77 to 86 ºF. 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. 41 ºF. Some of the water vapor 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 77 to 86 ºF, 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. 32 ºF and 91 ºF , respectively. 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 ■ dewatering belt ■ integrated cooling section
Technical data
Type LDT-50/5D LDT-100 LDT-140
Voltage 230/400 V, 50/60 Hz 230/400 V, 50/60 Hz 230/400 V, 50/60 Hz
Dimension (LxWxH) 22ft 1.6” x 6ft 8.3” x 7ft 11.5” * 22ft 4.9” x 8ft 3.6” x 11ft 3.0” * 26ft 10.4” x 12ft 7.0” x 12ft 2.3”
Belt width
Capacity**Iceberg lettuceSpinachBaby leaf
Max. 1300 lbs/hrMax. 880 lbs/hrMax. 660 lbs/hr
Max. 2,800 lbs/hrMax. 1,700 lbs/hrMax. 1,450 lbs/hr
Max. 5,000 lbs/hrMax. 3,050 lbs/hrMax. 2,600 lbs/hr
* Several configurations/lengths are available** Capacities based on 8% incoming and 1% exiting attached moisture
The difference is in the details...
Closed systemNo energy is dissipated to the environment because drying takes place in a closed system.
Gentle product handlingThe thermal drying process minimizes any product damage. It enables the product to be dried to a moisture retention level of 0% if so desired. 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.
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The drying processWarm air with low relative humidity is blown through the product from below 1 . The water on the leaf surface evaporates as the warm 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 chiller 2 . Here, the air temperature is decreased so that a major fraction of the water vapor condenses onto the cooling fins. The condensed water is collected in a drain and removed from the unit. A second heat exchanger 3 heats up the circulation air again to its initial condition 1 (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.
Hygienic designAll the components in the air drying tunnel are accessible for optimum cleaning.
