Frequently Asked Questions

  1. What does the system consist of?

    The system components are:

    • A removable flue blocker.
    • End curtain assemblies with plastic belt fog curtains.
    • Suction canopies at both ends which collect the waste fog.
    • Air hoses and air curtains.
    • A side channel blower which simultaneously clears hot fog and supplies air to dry the packages.

  2. How does this new kitset system work?

    Most of the energy used to run a standard shrink tunnel is used to evaporate water and suck it up a flue. The new system minimises evaporation. Hot water vapour is trapped inside the tunnel so that the humidity rises and evaporation slows down dramatically.

  3. What issues are involved in blocking the flue?

    We supply a removable stainless flue blocker. New customers can be assured that if there is any delay during upgrade installation the tunnel can be quickly put back to its original configuration using the flue. Some flues are not weather proof and admit rain water. The standard “Chinese hat” design can be a source of potential external contamination. It may be necessary to fit a rain water drain until the flue is removed.

  4. What materials are used to make the kitset?

    All major components are either stainless steel, Intralox conveyor belting or flexible PVC sheet and tubing.

  5. How much field experience has there been with the system?

    The first installation has been in continuous operation since June 2009.

    At the time of writing there are fifteen tunnel systems and one semi-automatic dip tank. Total field experience (midway through 2012) is now approaching 20 years of tunnel operation.

  6. Are there other benefits with the system besides energy and water saving?

    Fewer electrical maintenance issues. Better temperature control. Many tunnels are unable to maintain the desired temperature due to lack of heating capacity.

    Water savings and reduced descaling. A typical shrink tunnel with a flue can evaporate between 60 and 90 litres of water per hour. Salts dissolved in the water remain in the tunnel and must to be removed by regular descaling. A converted tunnel will typically evaporate say 60% less water so will deposit 60% less scale.

    Where there is an adequate existing side channel blower the cost of a new blower it is avoided.

    Air drier improvements. Excessive air flow from the water removal device can cause cold or wet working conditions for nearby workers plus wet air flow back through the tunnel. We have had success in overcoming many of these issues.

  7. You claim that the kitset system allows the waste hot fog to be released into the packaging room without increasing the load on the air refrigeration system. How is that possible?

    This claim is based on experience not theory. We think the some of the reasons might be as follows:

    • Existing flues fitted with a fan suck cold air out of the room. Blocking the flue saves the energy that was used to cool that air.
    • The outside of the existing flue gets hot thus heating the room. This heat load on the refrigeration system is removed by blocking the flue.
    • The system applies evaporative cooling to the waste hot fog.

  8. Can you prove your claims for high energy savings?

    We use a Beha electrical power analyser and data logger. It records voltage, current, total kilowatts etc. for all three phases plus total power. We take these readings before and after fitting the kitset and analyse them using computer spread sheet software. A typical, electrically heated New Zealand tunnel, running 300 shifts per year, has a payback period of about one year.