8 replies to this topic

[rangeleski]

Hi All,
Need some help on validating plastic caps on pet bottle for leakage. Any body have some data and reference on this.
Thanks


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[Charles.C]

Hi All,
Need some help on validating plastic caps on pet bottle for leakage. Any body have some data and reference on this.
Thanks


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Hi rangeleski,

 

As per yr previous topic, some further context is likely required to avoid misunderstandings.

 

eg Process ?

[rangeleski]

Ok,
We are a company that presses orange juice into PET bottles with lids. 5 units are taken from the line at startup and laid on side for 15 minutes. We then observ if any signs of leakage from caps is present. This is highlighted as a QCP in our HACCP system. What validation data would I use.


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[mahantesh.micro]

Hi,

Torque testing may be helpful for your leakage test. Set the limit for toque at which you find no leakage (ensure that the caps should be easily opened) and make this as your limit. 

[pHruit]

As mahantesh.micro suggests, torque spec is often used for verification during processing (assuming these are screw caps).

Have you specifically been challenged on whether your current test is capable of proving that a bottle is sealed?

Failing that, it's basic physics - a leak is caused by a gap, which from the perspective of the fluid in the bottle is simply a region in which the uniform pressure it exerts at its boundaries isn't being reciprocated. A valid test to determine this is therefore one that exposes the entirety of the cap area to the liquid, in an environment where the pressure outside the bottle is less than or equal to that on the inside - to help with this you could always put a weight onto the bottle, as this will help increase the pressure differential in favour of the liquid being pushed out if the seal isn't correct. Broadly your position is that of Newton's 3rd law

[zanorias]

Failing that, it's basic physics - a leak is caused by a gap, which from the perspective of the fluid in the bottle is simply a region in which the uniform pressure it exerts at its boundaries isn't being reciprocated. A valid test to determine this is therefore one that exposes the entirety of the cap area to the liquid, in an environment where the pressure outside the bottle is less than or equal to that on the inside - to help with this you could always put a weight onto the bottle, as this will help increase the pressure differential in favour of the liquid being pushed out if the seal isn't correct. Broadly your position is that of Newton's 3rd law

 

Aka "hold upside down and squeeze"?
 

[pHruit]

Aka "hold upside down and squeeze"?
 

Yep, but a specified weight takes the variability out of it, because at some point an auditor will challenge it

[mahantesh.micro]

Agree with Mr. pHruit & Mr. Zanorias, but Mr. Rangeleski wants to validate this control point (QCP). So its better to have torque testing which can be validated easily that that of bend upside down and squeezing the bottle.

 

One more option we can think of is thread security test which is broadly used in hermetically sealed glass bottles with lug caps. I have no idea exactly whether we can apply it to PET bottles with screw cap.

 

Regards

Mahantesh

[pHruit]

Agree with Mr. pHruit & Mr. Zanorias, but Mr. Rangeleski wants to validate this control point (QCP). So its better to have torque testing which can be validated easily that that of bend upside down and squeezing the bottle.

 

One more option we can think of is thread security test which is broadly used in hermetically sealed glass bottles with lug caps. I have no idea exactly whether we can apply it to PET bottles with screw cap.

 

Regards

Mahantesh

 

Wasn't entirely clear to me whether the OP wanted to validate his method or the QCP itself, but either way the responses here should hopefully help