GRE were contracted to design, manufacture and install a bespoke, twin‑coil dehumidifier/chiller and cooling‑tunnel unit for the NHS Saliva testing laboratory at the University Hospital, Southampton, UK. The purpose of the machine was to keep saliva samples within certain temperature parameters, as they travelled along a long conveyor belt from their delivery point into an automated sample testing lab.
The machine took ambient air from the process room and passed it through one of two blown dehumidification/chiller coils (GRE designed the machine to incorporate two separate coils, so that one could be switched out and defrosted while the other provided enough duty to keep the cooling tunnel within temperature set points. This ‘processed’ air then exited the chiller through an actuated duct connection, directly into the cooling tunnel (which encapsulated the existing conveyor), in order to maintain the temperature of the vial holders/samples between +4 and +8 °C, depending on the user setting (the machine was able to run cooler if needed). The machine used a remotely located closed‑loop/pumped air‑blast, water‑cooling system for heat rejection.
The cooling tunnel itself was designed with prefabricated modular, dual‑skinned, stainless‑steel panels (with insulation between the inner and outer skins) for easy site installation and featured an internal airflow path boosted by multiple fans, to ensure even temperatures throughout the full length. It was also fitted with multiple temperature sensors to ensure that cooling was provided evenly at the correct temperatures; the sensors also provided feedback to the machine, which modulated its output dynamically, to achieve/maintain the correct temperature.
The machine also incorporated datalogging functionality to record the tunnel temperature over operational periods. This data was available for download for client retention. The tunnel was also fitted with access holes for the insertion of an independent, calibrated temperature‑measurement device for temperature validation.
All design, analysis, manufacture, software and installation were undertaken by GRE.
