Experiment: When an airtight container is knocked over, how much water will leak out?

NITTO KINZOKU KOGYO’s airtight containers have 2 different kinds of sealing lid: clip-down type “CTH” and lock lever ring type “CTL”.

All of them are sufficiently airtight for use in storage, etc. However, it is not clear how much of the contents will leak when the container is in an abnormal condition.

In order to confirm this, we checked the amount of water leakage by laying down two types of containers. So, how much difference do they have?

Differences between "clip-down" type and "lock lever ring" type sealing mechanism

NITTO KINZOKU KOGYO’s airtight containers have 2 different kinds of sealing lid: clip-down type “CTH” and lock lever ring type “CTL”. Let’s start with a brief explanation of each.

Clip-down type "CTH"

It is a type to fix the lid with a clip attached to the container body. Depending on the container size, there are 3 ~ 6 clips attached that can be tightened with one hand. It is relatively easy to handle.

For standard specifications (containers with an inner diameter of 470 mm or less), the gasket is attached to the main body side of the container.

Lock lever ring type "CTL"

The lid is fixed with a stainless steel band. Although it needs to be handled with both hands, unlike the clip-down type, it can be fixed with one-time tightening.

The gasket is attached to the lid side.

The concept of "airtightness" in NITTO KINZOKU KOGYO:

It means “Sealed so as to prevent contamination of solid matter (dust, etc.) from the outside when closed tightly so as not to leave any gaps during normal handling” (according to the Japanese Pharmacopoeia).

It is not designed to be completely sealed to prevent leakage of liquid and powder and leakage of gas when the container is rolled or shocked.

2. Experiment: When layed down, how much water will leak out?

Our company’s containers are designed to prevent the contents from spilling during normal use. What would happen if we lay down the containers?

This time, we put tap water in the container and laid them down to one same side, and confirmed the leakage of the clip-down type and lock lever ring type in three kinds of experiments.

Please NOTE:

This experiment is simple and not intended to demonstrate the performance of the product. Since no scientific verification has been conducted, the reproducibility of this experiment is not guaranteed. Please read it just for reference.

2.1. Both are hard to leak if they are only rolled over (for 5 minutes).

First, we put the container gently down on one side and left it for 5 minutes. The containers used are CTH -30 and CTL -30 (both having 20L capacity), and the amount of liquid will be tested in 4 stages.

We measure the total weight before and after we lay down the container for 5 minutes and check the difference.

As shown in the table above, there was no change in the amount of liquid in either container. There were also no visible leakage.

2.2. Situation of laying down for a week: Lock Lever Band wins

Although all those 2 kinds of containers didn’t leak for only 5 minutes, if you leave it for a longer time, it might leak out, so this time we left them for a week to see how it goes. This time, the experiment was conducted only when the water was full (20 L).

This time the difference occurred. While there was no change in the lock lever ring type, the clip-down type leaked 0.08 kg, or 80 ml.

When we visually checked them, 2 hours after they were laid on one side, the water-absorbent sheet under the clips began to swell (means water leaked). On the other hand, for the lock lever ring type, we could not confirm any leakage visually.

Our company containers are not intended to be stored sideways or lying down. However, if you need the container to be lying on one side, the lever ring type is safer.

2.3 The difference is more significant when shock/impact applied

Finally, we checked the amount of leakage in case of giving an impact.

This time, for a simple experiment, the container was fallen three times by hand from a stand about 250 mm high to check the amount of leakage. The amount of water is 16L (80%).

There is a big difference in the amount of leakage compared to when it is simply left lying on one side. While the lever ring type leaked 40 ml, the clip-down type leaked about 1.5 L.

When we conducted a visual confirmation, the amount of leakage of the lever ring type did not change as much as the times of drops was increased, but the clip tightening power of the clip gradually weakened and eventually the gasket popped out. This may have caused the large amount leakage of clip-down type container.

When using the clip-down type, If the container falls down or is dropped, the tightening force of the clip may be weakened as in this experiment. When you use the container again, it is better to check if there is no problem with the tightening force.