How does a balloon with glue-foam work? Cut with a grinder to see the valve design

How the foam cylinder works is clear to many: a thin metal cylinder (with sealed caps) and a valve. But how exactly the valve is arranged, that when you press the fitting or tilt it with the tube, it works - it was always interesting.

A batch of empty cylinders has accumulated. My childish interest prevailed and I decided to cut one of them with a grinder. Why did I mention exactly about glue-foam - because I use it in aerated concrete masonry. The foam container is similar.

There was some foam inside. Black plaque is the plastic from the valve that stuck when cutting the cylinder.

Valve close-up. The cover and valve are double seamed. Apparently, the valve is made separately, and the cylinder is made separately and the cylinder is sealed on the filling line. Though theoretically one rolled joint can be made.

There are no metal springs inside the valve that press the valve. Springs are used in aerosols and gas cylinders. Here pressure presses the plastic nipple against the rubber seal.

If the nipple is pushed inward while screwing onto the foam gun, the hole opens and the foam comes out. This also happens if you tilt the union. Valve diagram:

The stem is made of polyolefin plastic. A rubber seal made of rubber with increased resistance to swelling. Sheet thickness: 0.4 mm. Differences between a professional cylinder (for a pistol) and a household one - in stock:

The external difference between a professional and a household foam cylinder:

The rubber part of the valve does not withstand any pressure. Therefore, it is not recommended to heat the cylinder or store it at temperatures above +35 g. There are many funny photos on the Internet when the cylinders are overheated in a car in the heat or on a stove (in water - for better foam output).

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