29)Type 4 : composite cylinder with polymer liner

Type 4 CNG cylinders are a type of CNG storage cylinder that feature a composite construction with a polymer liner. They are known for their lightweight design and high-pressure storage capabilities. Here are some key features of Type 4 CNG cylinders:

Construction: Type 4 cylinders consist of a polymer liner, typically made of high-density polyethylene (HDPE), which is reinforced with multiple layers of composite materials, such as fiberglass or carbon fiber. The polymer liner acts as a gas barrier, while the composite layers provide structural reinforcement.

Lightweight Design: Type 4 cylinders are extremely lightweight compared to other types of CNG cylinders. The use of a polymer liner and composite materials allows for a significant reduction in weight, contributing to improved vehicle fuel efficiency and increased payload capacity.

Pressure Rating: Type 4 cylinders have high-pressure ratings, typically ranging from 250 bar (3,600 psi) to 350 bar (5,000 psi) or higher, depending on regulatory requirements. They are designed to safely store CNG at high pressures.

Gas Barrier Properties: The polymer liner in Type 4 cylinders acts as an effective gas barrier, preventing the permeation of CNG through the cylinder walls. This helps to maintain the integrity of the stored gas and ensures the safety of the cylinder.

External Protection: Type 4 cylinders are often coated with an external protective layer or paint to provide corrosion resistance and enhance durability.

Inspection and Testing: Type 4 cylinders undergo stringent testing and certification procedures to ensure compliance with safety standards. This includes hydrostatic testing, ultrasonic thickness testing, and visual inspections to assess the cylinder’s integrity and condition.

Compatibility: Type 4 cylinders are compatible with various CNG vehicles and can be used in different applications, including cars, buses, trucks, and other commercial vehicles.

Safety Considerations: Proper installation, handling, and maintenance are essential for the safe use of Type 4 cylinders. It is important to follow manufacturer guidelines, local regulations, and best practices for cylinder installation, inspection, and maintenance.

Type 4 CNG cylinders are highly regarded for their lightweight design, high-pressure storage capabilities, and excellent gas barrier properties. These cylinders have gained popularity in the industry due to their enhanced safety, improved vehicle efficiency, and increased storage capacity.