The opening in the top of the can is quoted as a standard figure because the valve and the can have to agree on it exactly. Choose an unusual one and the range of valves and actuators available to you narrows sharply.
This page covers the common openings, why the choice constrains so much later work, and the list of things to settle before approaching a supplier.
The common openings
| 1 inch (25.4 mm) | General-purpose aerosols The standard opening for most cans. Most valve types, actuators and spray patterns are built around it |
|---|---|
| 20 mm | Intermediate and smaller formats A narrower opening used where the format is smaller or the dose is tighter |
| 13 mm | Small formats The narrowest of the common openings; fewer valve options are available for it |
Why the opening size decides so much
- It decides which valves exist for your project. Valve makers build to the standard openings. Choose an unusual one and the choice of valve, actuator and spray pattern narrows sharply.
- It constrains the spray, without fixing it. The opening sets what can be fitted; the spray rate and pattern then come from the valve and the actuator. Get the opening wrong and no actuator will rescue the result.
- It is a pressure boundary. The crimped joint between valve and can is the seal that keeps the propellant in. It is dimensioned and controlled for that reason.
- It affects filling. A narrower opening means a smaller path for the product going in, which matters if your filler is working to a cycle time.
How to specify a valve properly
Suppliers can only quote accurately if the brief covers all of these, so it is worth assembling them before you approach anyone:
- Opening / crimp diameter — 1 inch (25.4 mm), 20 mm, 13 mm, or another standard.
- Valve function — continuous spray, metered dose, or a bag-on-valve assembly.
- Actuator and spray pattern — the user-facing part, and often the last thing decided even though it defines the experience.
- Gasket material — it has to tolerate your formulation, not just the propellant.
- Product characteristics — viscosity, solids, and whether the formula is aggressive enough to need a particular internal coating.
- Fill method — how the filler puts product and propellant in, since that has to match the assembly you choose.
Crimp quality is a dimensional check, not a visual one
A crimp that looks right can still leak. The dimensions are checked and logged in-line during forming like the rest of the can geometry, which is why a batch can be traced back to the tooling that made it — see the testing laboratory for the equipment involved, and the certificates page for what is recorded.
Frequently asked questions
What is the crimp diameter, in plain terms?
It is the diameter of the opening in the top of the can where the valve is pressed and rolled into place. The valve and the can have to agree on it exactly, which is why it is quoted as a standard figure rather than measured case by case.
Which valve size do most aerosols use?
The 1-inch opening — 25.4 mm — is the general-purpose size and the one most valves and actuators are built around. The smaller openings exist for smaller formats and for products where a narrower valve suits the dose.
Does the valve size change how the product sprays?
It constrains what you can choose. The opening determines which valves fit at all; the spray rate and pattern then come from the valve and the actuator on top of it. Pick the opening first, then tune the spray.
Which valve sizes can you supply?
[待确认：我们可提供的阀门口径与阀件型号范围] — we would rather confirm this against our current component list than print a range here and have you plan around it.
Next step
Tell us the opening you need, the product it has to deliver and the fill volume. If you are still choosing, send the formulation and how the product will be used and we will suggest the opening and valve combination rather than leaving you to guess from a catalogue. See the product pages for can sizes.