Leak testing device and method for plastic bottles

Method for leaking resting lightweight plastic bottles comprising:

• a. transporting a single row of a plurality of lightweight bottles serially in an upright orientation along a linear path through a plurality of test stations;
• b. sensing the entrance of bottles into said test stations and generating a command signal when a set of bottles have entered the test stations;
• c. temporarily stopping a bottle at each test station on said path in response to the command signal;
• d. reciprocating a test head from each test station into sealing relationships with the mouths of said bottles;
• e. charging a plurality of constant volume reservoirs to a predetermined pressure with a fluid;
• f. placing each of said bottles in communication with one said reservoir through its associated test head to establish a bottle-reservoir volume system;
• g. sensing the pressure of each of said systems and comparing it with a given pressure corresponding to a no leak system pressure;
• h. automatically ejecting each of said bottles from a test station whose system pressure is below said given pressure by ejecting means which are responsive to the comparing means;
• and
• i. releasing the remaining bottles on said path for continued movement therealong.

Apparatus for leak testing lightweight plastic bottles comprising:

• a. a plurality of test stations each having a retractable head;
• b. conveyor means for transporting said bottles through said test stations;
• c. means at the upstream end of said test station for sensing the entrance of bottles into said test stations and generating a command signal when a set of bottles have entered the test station;
• d. retractable gate means at the downstream end of said test stations for temporarily preventing the exit of said bottles and aligning the bottle mouths in register with said head in response to said command signal;
• e. means for moving each of said heads into and out of sealing engagement with its associated bottle leak test means at each test station including:
• i. reservoir means for receiving and containing a given volume of pressurized fluid from a source,
• ii. control means responsive to said command signal for segregating said reservoir means from said source and placing said reservoir in communication with its associated head, whereby a test pressure-volume relationship is established between the reservoir and bottle, and
• iii. means for sensing the pressure of said test pressure-volume relationship and comparing said sensed pressure to a set point value;
• f. lateral ejector means operatively connected to said comparing means for displacing the associated bottle if said sensed pressure is below said set point value;
• and
• g. means operatively connected to said test stations and said retractable gate means for retraction of said gate means when the testing is complete whereupon said conveying means transports said tested bottles from said testing stations and transports untested bottles to said testing stations.