Typically, during the chill down process when freshly slaughtered cattle are cooled from a nominal 37°C to 12°C in a period of 12 hours, the cattle lose by weight up to 3% due to moisture loss. The loss of moisture occurs primarily during the early stages of the cooling process when the supply air from the chiller plants is at its lowest and the carcases are at their highest temperature.
The loss from a typical side of beef is 6kg; this factored by the number of sides in the store can have a major cost implication to the abattoir.
The principle of abattoir humidification to reduce the weight loss is adopted as it is not permitted to spray water directly onto the sides of beef. By humidifying, it is possible to raise the humidity in the chill down room so that, as the chilled air is warmed by the carcasses, it absorbs moisture from the air rather than drawing it from the meat, thus preventing the weight loss.
The typical store will hold 270 head of cattle or 540 sides of beef; this with an average weight loss of 3% amounted to a loss of 2,916kg per chill down cycle of 12 hours. This weight loss can be costed, as the average cost by weight of the live cattle is £1.65 per kg. This gave a financial loss of £4,800 per day per store.
The JetSpray compresed air and water humidifier is ideal for abattoir and meat processing applications. Rows of precision engineered spray nozzles are positioned against the outside walls of the store and spray against the airflow from the evaporators. This ensures that there is good mixing of the moisture with the air and that there is no moisture entrainment with consequential wetting out on the carcasses.
The nozzles are controlled via a control panel with the output being modulated in relation to the off coil air temperature from the evaporators so that as the carcass temperature falls the requirement for cooling decreases so the output from the sprays are reduced.
As an example to its effectiveness, by using the Jetspray humidification system in one cattle abattoir, the losses from the stores fell from 3% to around 0.5%. This cost saving when compared to the cost of the humidifier's supply and installation gave a payback on the investment of just four weeks.