Different Types of Pressure Vessel


NPROXX designs and manufactures high-quality Type 4 pressure vessels for hydrogen storage under high pressures. In fact, our team developed and certified one of the very first Type 4 pressure vessels more than 20 years ago. We believe that innovative hydrogen storage solutions will be a crucial part of the future hydrogen economy.

What’s a Type 4 Pressure vessel?

To understand why Type 4 is so suitable for this role, you need to know the different types of pressure vessel:

  • Type 1: A traditional all-metal bottle made of steel used for storing liquid and gases for industrial processes. Cheap to produce, but heavy
  • Type 2: An additional layer of carbon fibre reinforcement is added round a steel inner tank and shares the load with the metal. This gives it added strength and reduces weight, but makes it more expensive than Type 1
  • Type 3: A carbon-fibre composite vessel, with a steel or aluminium vessel inside. The carbon fibre outer vessel takes the load. With more carbon fibre involved, costs are higher than type 2, but higher pressures can be achieved
  • Type 4: A vessel made of all carbon fibre, with an inner liner of polyamide or polyethylene plastic. Characteristics are a much lower weight and very high strength. Comparatively expensive, because of the volume of carbon fibre

What are the advantages of a Type4 pressure vessel?

While most basic storage needs can be fulfilled by basic Type 1 vessels, weight becomes a factor when pressure vessels need to be transported. The weight of metal and part-metal tanks adds to the cost of transport and this is where carbon fibre becomes appealing.

Another factor is strength. Carbon fibre adds innate strength to the vessel, enabling it to take on greater loads. Carbon fibre also significantly increases the corrosion resistance and the fatigue resistance of pressure vessels, which makes safety a key advantage.

Finally, the other key advantage of carbon fibre composite pressure vessels (type 4) is volume. Because of their innate strength, carbon fibre type 4 pressure vessels can store hydrogen at high pressures. By combining several of these within a container unit, large volumes of hydrogen can be stored, which reduces the traffic from producer to consumer and decreases the energy consumption during transportation.