Leak detector for sealed containers

Claim 2

A leak detector for testing sealed containers formed of flexible or semi-rigid material, said detector comprising: A. a chamber for enclosing a container to be tested, B. means to pressurize said chamber to cause a perfectly sealed container to distort due to the difference between internal container pressure and chamber pressure, a slightly imperfect container undergoing a small loss of distortion after a predetermined time period and a highly imperfect container experiencing no distortion, C. a sensor in the chamber responsive to a dimension of the container to produce a signal indicative thereof, D. means to derive a first signal from the sensor before the chamber is pressurized and to hold the first signal, E. means to derive a second signal from the sensor when the chamber is pressurized and upon the conclusion of said predetermined period, F. means to compare the second signal with said held first signal to provide an output value indicative of a perfectly sealed container, a slightly imperfect container or a highly imperfect container, and G. means responsive to said output value to accept a perfectly sealed or slightly imperfect container or to reject a highly imperfect container.

Claim 3

A leak detector as set forth in claim 1, wherein said first and second signals are analog signals.

Claim 4

A leak detector as set forth in claim 1, wherein said first and second signals are digital signals.

Claim 5

A leak detector for testing a batch of sealed containers formed of flexible or semi-rigid material, said detector comprising: A. a chamber for enclosing the batch of containers to be tested, B. means to pressurize said chamber to cause a perfectly sealed container in said batch to distort due to the difference between internal container pressure and chamber pressure, a slightly imperfect container undergoing a small loss of distortion after a predetermined time period and a highly imperfect container experiencing no distortion, C. a group of sensors in said chamber, each coupled to a respective container in the batch thereof to produce an analog signal indicative of a container dimension, D. an analog-to-digital converter, E. means to apply the signals from said sensors, before said chamber is pressurized, sequentially to said converter to produce a first series of equivalent digital signals, F. means to hold said first series of digital signals, G. means to apply the signals from the sensors when said chamber is pressurized and after said predetermined period has elapsed, sequentially to said converter to produce a second series of equivalent digital signals, H. means to compare each held signal in the first series with the corresponding signal in the second series to provide an output value indicative of a perfectly sealed container, a slightly imperfect container or a highly imperfect container, and I. means responsive to said output value to accept the batch of containers if all containers therein are perfectly sealed, and to reject the batch if any one container is imperfect, or to reject any individual container in the batch.

Claim 6

A leak detector for testing a batch of sealed containers formed of flexible or semi-rigid material, said detector comprising: A. a chamber for enclosing the batch of containers to be tested, B. means to pressurize said chamber to cause a perfectly sealed container in said batch to distort due to the difference between internal container pressure and chamber pressure, a slightly imperfect container undergoing a small loss of distortion after a predetermined time period and a highly imperfect container experiencing no distortion, C. a group of sensors in said chamber, each coupled to a respective container in the batch thereof to produce an analog signal indicative of a container dimension, D. an analog-to-digital converter, E. means to apply the signals from said sensors, before said chamber is pressurized, sequentially to said converter to produce a first series of equivalent digital signals, F. means to hold said first series of digital signals, G. means to apply the signals from the sensors when said chamber is pressurized and after said predetermined period has elapsed, sequentially to said converter to produce a second series of equivalent digital signals, H. means to compare each held signal in the first series with the corresponding signal in the second series to provide an output value indicative of a perfectly sealed container, a slightly imperfect container or a highly imperfect container, and I. means responsive to said output value to accept the batch of containers if all containers therein are perfectly sealed, and to reject the batch if any one container is imperfect, or to reject any individual container in the batch.

Claim 7

A detector as set forth in claim 4, wherein said means to hold said first series of signals is constituted by a series of digital storage registers.

Claim 8

A detector as set forth in claim 4, wherein said means to compare each held signal in the first series with the corresponding signal in the second series is constituted by a digital comparator.

Claim 9

A detector as set forth in claim 6, wherein said means responsive to the output value of each digital comparator includes a first storage register.

Claim 10

A detector as set forth in claim 7, further including an indicator coupled to said first storage register to indicate the condition of the seal under test.

Claim 11

A detector as set forth in claim 8, further including means coupled to said indicator to determine the frequency of defective seals.