GrainPro TranSafeliner™ (Patent Applied For)

A gas- and watertight liner for “transit fumigation” of shipping containers and prevention of condensation

Shipping containers containing costly commodities are moving world wide from one climate to another. While they are on the move the ambient climate conditions change whereas the commodity inside the container can become infested or suffer from changes in moisture content due to the changes in the outside ambient conditions. GrainPro’s TranSafelinerTM provides protection against moisture ingress and condensation and simultaneously enables environmentally friendly fumigation of the commodity transported, thus ensuring arrival of the commodity to destination without infestation and without condensation or moisture ingress.

Fumigation:
The gas tight TranSafeliner™ is an efficient gas barrier for O2 and CO2. Once the container is loaded either manually, by forklift or in bulk, the commodity stored will either generate its own “modified atmosphere” or in certain cases and under specific conditions, insertion of CO2 into the TranSafeliner™ may be required. While the container is shipped fumigation will take place and on arrival the TransSafeliner™ may be opened, without the risk of any hazardous gas to operators or personnel. TranSafeliner™ is an ideal solution for organic commodities.

The Storage Principle
All properly dried agricultural commodities targeted for this storage system have prolonged shelf life due to their low moisture contents. However, under normal storage conditions they are all susceptible to damage and quality deterioration by stored product insects. Furthermore, many of the products are subject to oxidative changes during storage that have an adverse effect on colour, taste or nutritive value. In contrast, storage under modified atmospheres whereby the oxygen in the air surrounding the commodity is replaced by either carbon dioxide or nitrogen, prevents both the development of insects and oxidative processes within the commodity.

Self generated modified atmospheres by insect infestation
Many commodities such as grains, beans and pulses contain large populations of insects, even when fumigated. The usual exposure times in commercial fumigation are too short to kill insect pupae, larvae and eggs, which easily hatch in the commodity during a journey lasting several weeks. Commodity traders face embarrassing situations when fumigation was supposedly performed at origin and at arrival visible infestation was observed resulting in complaints and claims. Given the heat and moisture levels in shipping containers, the “hidden” insect population will rapidly develop. While doing so inside the gastight TranSafelinerTM this population will cause rapid depletion of O2 and a sharp increase in CO2, thus controlling and killing itself. This “hermetic” storage principle is successfully applied in other GrainPro products for many years.

Prevention of Condensation
During transport condensation may occur as a result of enhanced convection currents prevailing inside the container due to the heat gradient that develops between the top and the wall-floor sections of the container. Excess of moisture is converted into water droplets at the roof of the container and drips on the surface of the shipped commodity as well along the walls of the container, causing damage to the commodity.

Condensation is prevented by use of the TranSafeliner™. This “sleeve” made of proprietary gas tight material prevents translocation of moisture from the commodity into the container atmosphere and prevents the ingress of any moisture. After loading, the liner is left loose and tight to the bags. In a normally loaded container there is always a space of at least 10-20 cm (4-8”) between the roof and the bags. This is the headspace layer of air that remains under the influence of convection currents enhanced by temperature gradients. The worst cases of condensation occur when the containers are exposed to the sun reaching container roof temperatures of 40-50oC and more during the day and cooling to 15-20^oC during the night. These temperature variations significantly enhance air movement by convection currents that cause translocation of moisture from the unprotected commodity (without sleeve) to the roof of the container and from there to the top layers of the commodity.

The most dangerous situation is when a heated headspace of 40^oC or more absorbs moisture from the commodity. There is a tendency of that headspace air to equilibrate to the same relative humidity as of the commodity. At 40^oC and 70% RH the absolute water content of air is 36 g water/m³ air while when it cools to 20^oC it is only 10 g/m³ air. The difference is deposited on the container roof translocated there by convection air currents, and then on the commodity condensation.

When this heated headspace is isolated from the commodity, meaning having no supply of water; its water content remains no more than 40 g/m³. This moisture depleted atmosphere is achieved by the isolating effect of the TranSafeliner™ that renders minimizes temperature gradients at the headspace of the container.

Installation

Advantages of storage under modified atmospheres are:

• By using a strong fan causing the liner to be stuck to the container wall
• Using cable ties and tape to hang the liner to the loops at the top corners of the container. While loading the liner is pulled from the loops and will remain loose on top of the commodity.

After loading the opening of the TranSafeliner™ is stretched horizontally and subsequently sealed with a special gas tight tape provided with the tape.

Reusable and recyclable
TranSafeliners™ are made of recyclable plastics and can be reused as long as undamaged. Small punctures can be repaired with the special tape.

A kit of TSL contains liner, sealing tape, set of cable ties and installation instructions.

Option 1 : installation of liner using a fan

Figure 1. Laying the liner inside the container	Figure 2. Positioning blower 5 meters away from container
Figure 3. Blown up TSL inside the container.	Figure 4. Testing accessibility of fork lift

Option 2: installation with rings

Figure 5. Attaching the ring	Figure 6. Fastening the ring to the container loop
Figure 7. Installed	Figure 8. Installed
Figure 9 Before closing the container.