196 Meat refrigeration Table 9.3 Claimed advantages of liquid nitrogen refrigerated vehicles Advantages of nitrogen refrigerated vehicles Minimum maintenance Improved vehicle utilization Accurate temperature control Rapid initial temperature reduction Uniform cargo temperature Modified atmosphere transportation Silent Environmentally acceptable Low capital costs Multicompartment triple-temperature operation Low operating costs Flexible refrigeration Source: Smith. 1986 6 6.57.58.59.510.511.512513.514.515.516.51751 Temperature(C) Fig 9.1 Deep leg temperatures when loaded into railway wagons or road trailers (source: Gill and Phillips, 1993) 420 86420 0.5 Fig 9.2 Maximum surface on beef sides and quarters when loaded(source: Gill and Phillips, 1993) were also high and ranged from 0.5 to 6.5C (Fig 9.2 ). In rail wagons the surface temperature decreased during the first 24 h and was subsequentl maintained at a temperature of 0+1C. In the road vehicles the surface emperature fell slowly during the whole journey and had not attained a steady minimum value when unloaded. On average the deep temperature of sides in rail wagons reached 1C after 72h. Temperatures in quarters in road vehicles were still above 2 C after 120hwere also high and ranged from 0.5 to 6.5°C (Fig 9.2). In rail wagons the surface temperature decreased during the first 24 h and was subsequently maintained at a temperature of 0 ± 1 °C. In the road vehicles the surface temperature fell slowly during the whole journey and had not attained a steady minimum value when unloaded. On average the deep temperature of sides in rail wagons reached 1 °C after 72 h. Temperatures in quarters in road vehicles were still above 2 °C after 120 h. 196 Meat refrigeration Table 9.3 Claimed advantages of liquid nitrogen refrigerated vehicles Advantages of nitrogen refrigerated vehicles Simple, dependable operation Improved pay loads Minimum maintenance Improved vehicle utilization Accurate temperature control Rapid initial temperature reduction Uniform cargo temperature Modified atmosphere transportation Silent operation Environmentally acceptable Low capital costs Multicompartment triple-temperature operation Low operating costs Flexible refrigeration Source: Smith, 1986. 0 2 4 6 8 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5 17.5 18.5 Temperature (°C) Frequency Rail Road All Fig. 9.1 Deep leg temperatures when loaded into railway wagons or road trailers (source: Gill and Phillips, 1993). 0 2 4 6 8 10 12 14 Frequency 0.5 1.5 2.5 3.5 4.5 5.5 6.5 Temperature (°C) Rail Road All Fig. 9.2 Maximum surface on beef sides and quarters when loaded (source: Gill and Phillips, 1993)