Mục lục
Reviewed and updated by ICD - Week 24/2026
Quick summary:
- The valve is the most important technical part of a dunnage bag, deciding inflation speed and how well the bag holds pressure.
- Two technologies: the old-style valve (about 10 mm, slow) and the fast valve (20-30 mm, 2-3x faster, with a two-way auto-lock).
- Valves are made of engineering plastic (load-bearing PE/PP or nylon) that resists ageing and container temperatures from -20C to 50C.
- The gun must match the valve - a gauge or auto-cutoff ensures the correct working pressure.
What is a dunnage bag valve? Its core role
The valve is the single part that connects the bag’s inner PA/PE bladder to the compressed-air source. Its job is not just to let air in but to control pressure and keep it stable for the whole journey. For the basics, see what a dunnage bag is.
When the gun is fitted, air flows through the valve into the bladder. When the gun is withdrawn, the valve closes automatically (usually a spring or rubber diaphragm), stopping air escaping, and the cap is then tightened for a complete seal. Fast inflation builds the dynamic bracing force quickly and cuts waiting time at the packing area - at the yard, every minute of loading is money, so a valve that fills 3x faster raises throughput, not just convenience.
Valve technologies: old-style vs fast
Old-style valve
Small (about 10 mm diameter), using a screw or push cap. The narrow bore restricts airflow, so it is slower - on a large container bag (100 x 180 cm) it can take several minutes each, slowing loading.
Fast valve
The modern technology ICD prefers. A larger diameter (20-30 mm) with a bright-colored core (often red or blue). It inflates 2-3x faster than the old style - critical where handling time is decisive. It has a two-way auto-lock: airflow opens fully during inflation, then the valve locks instantly when the gun is withdrawn, preventing leaks. Usually fitted to heavy-duty bags such as Level 3 kraft and woven PP.
| Criterion | Old-style valve | Fast valve |
|---|---|---|
| Diameter | Small (~10 mm) | Large (~20-30 mm) |
| Inflation speed | Slow | 2-3x faster |
| Efficiency | Low, time-consuming | High, optimizes yard time |
| Use | Small or light-load bags | Container, heavy-load, fast bracing |
Valve material and durability
The valve must withstand continuous pressure and stay strong without cracking in use. It is usually high-grade engineering plastic (load-bearing PE/PP or nylon) with strengthening ribs, resistant to ageing and to container temperatures from -20C to 50C. The internal rubber gasket is the most important part for a leak-free seal. On woven PP bags, the valve is designed to deflate easily and be re-inflated many times without losing its seal.
Choosing a compatible inflation gun
The valve’s performance depends entirely on the gun. The gun must have a connector that matches the fast valve’s diameter and lock - an old-style gun cannot inflate a fast valve, and vice versa. Professional guns include a pressure gauge or auto-cutoff so you reach the recommended working pressure exactly (for example 0.2 bar for Level 1), avoiding over- or under-inflation. A leaking valve at the port can deflate a bag mid-voyage and let the load shift, so always test the valve seal before sealing the container. See how to use a dunnage bag.
Frequently Asked Questions (FAQ)
Why is a fast valve better?
Its larger bore inflates 2-3x faster and auto-locks, cutting yard time and ensuring a secure seal on heavy-load bags.
Can I use any gun with any valve?
No. The gun connector must match the valve type - old-style and fast valves need their own guns.
How does the valve hold pressure?
An auto-lock closes when the gun is withdrawn, and an internal rubber gasket plus the tightened cap give a complete seal across container temperature swings.
Can the valve be re-inflated for reuse?
On woven PP bags, yes - the valve deflates and re-inflates many times without losing its seal.
Contact ICD Viet Nam
For fast-valve dunnage bags and compatible guns, contact our team for a quote.
- Northern Vietnam: 0983 797 186 / 090 345 9186 / 090 5859 186
- Southern Vietnam: 098 6784 186
- Email: sales@icdvietnam.com.vn
- Zalo: Chat on Zalo
