Leak detecting system checking gas seal of food containers - has cowling lowered over box at end of prodn. line and passes suction tube through IR photo-spectrometer

摘要

Food stuffs, e.g. fresh chipped potatoes, are often packed in boxes after cooling to near freezing. The boxes are then evacuated and a gas such as nitrogen or carbon dioxide is injected into the box before sealing. Food treated in this way may be stored without deterioration for several weeks. The present system, which is at the end of a prodn. line, has a cowling which is lowered over such a box and partially evacuated by a vacuum pump. The suction tube passes through an infra red photo-spectrometer which detects any significant quantity of gas leaking from a box. Leaking boxes are removed from the production line. Alternative detectors, such as thermal conduction meters or ionisation analysers may be used in place of the infra red photo-spectrometer.