Air bellows, also known as pneumatic actuators or air springs, play a crucial role in high-pressure hydraulic systems. These systems require components that offer resilient vibration isolation, precise height control, and durability under extreme conditions. In this case study, we delve into the ways air bellows provide solutions to challenges in industrial environments, particularly in applications where high-pressure hydraulics are involved.
The Unique Role of Air Bellows in Hydraulic Systems
When it comes to high-pressure hydraulic systems, air bellows stand out due to their capability to handle variable loads, resist harsh conditions, and operate without the friction associated with conventional actuators. Unlike rigid actuators, Tevema air bellows provide a soft yet powerful actuation, making them suitable for environments where shock absorption and smooth force application are essential.
Key Benefits of Air Bellows in Hydraulic Systems
1. High Vibration Isolation Capability
Hydraulic systems often generate vibrations that can be harmful to sensitive machinery and structures. Tevema air bellows offer an exceptional vibration isolation capability, with natural frequencies as low as 1 Hertz. This means that they can absorb over 99% of unwanted vibrations, preventing damage to connected components. According to Parker Pneumatic, “vibration isolation properties are a crucial factor in extending machinery life and maintaining consistent performance”.
2. Flexibility in Operation and Design
Air bellows used in hydraulic systems provide operational flexibility. Unlike hydraulic cylinders that require complex seals, Tevema air bellows can work with different mediums, including compressed air, nitrogen, and oil. They are resistant to misalignment issues, which can be particularly useful in applications with angular motion or uneven mounting surfaces.
- Media Versatility: These bellows can use a range of mediums, such as nitrogen and even water with glycol, depending on the applicatio.
- Wide Temperature Range: Standard bellows can withstand temperatures from -30°C to +70°C, while specialized elastomer compounds can extend this range to +115°C.
3. High Pressure Handling and Compactness
In high-pressure applications, the ability to withstand extreme pressures is key. Tevema’s four-ply air bellows can handle pressures up to 12 bar, offering higher force capabilities compared to the standard construction. Despite their compact installed height, these bellows provide high load support and a flexible stroke range, making them suitable for high-pressure hydraulic actuations.
4. Maintenance-Free Operation
One of the significant advantages of using air bellows in hydraulic systems is their maintenance-free operation. With no internal rods or pistons to wear out, they eliminate the need for lubrication and regular upkeep, reducing downtime and maintenance costs. As Dunlop states, these components are “economical and virtually maintenance-free,” even under heavy-duty conditions.
Applications of Air Bellows in Hydraulic Systems
High-Pressure Lifting Mechanisms
Air bellows are frequently used in lifting mechanisms within high-pressure hydraulic systems. Their compact form factor and high thrust capabilities make them ideal for scissor lifts, presses, and platform lifts. In these applications, air bellows serve as reliable actuators that can produce significant lifting forces with minimal space requirements.
Vibration Isolation in Hydraulic Platforms
Hydraulic platforms, used in applications such as machinery vibration dampening, benefit greatly from air bellows due to their high isolation efficiency. The bellows can be installed to support and stabilize the platform, providing a cushioning effect that absorbs the high-frequency vibrations common in industrial environments. This capability not only extends the life of the machinery but also reduces noise levels significantly.
“The key to effective vibration isolation lies in controlling the natural frequency of the isolator. Air bellows have a unique ability to maintain consistent natural frequencies across various load changes.” – Quote inspired by Dr. Heinrich Hertz
Height and Level Control in Heavy Machinery
In heavy industrial setups, maintaining consistent operational height and level is crucial for ensuring productivity and safety. Tevema air bellows can be easily adjusted to maintain the height of platforms or machinery components by regulating internal air pressure. This adjustment capability ensures accurate height control, even under changing load conditions, which is a key benefit over traditional coil springs.
Case Example: Hydraulic Press Actuation
A hydraulic press equipped with Tevema air bellows was able to significantly improve its precision and response time. The bellows allowed the press to be operated smoothly without the need for complex hydraulic circuits or piston assemblies, reducing both complexity and cost of the system.
Design and Installation Considerations
Choosing the Right Air Bellow Configuration
Selecting the correct air bellow depends on various factors, including load capacity, stroke requirements, and pressure conditions. Tevema offers a variety of single, double, and triple convoluted air bellows to suit different applications. The convoluted design helps in achieving a balance between stroke length and load capacity, which is critical for the effectiveness of the actuator.
- Single Convoluted Bellows: Ideal for short strokes and compact installations.
- Double and Triple Convoluted Bellows: Suitable for applications needing longer strokes and greater load-bearing capacity.
Installation Best Practices
During installation, it is vital to ensure that stroke limitations are respected to prevent damage. The air bellows should not be overstretched, especially when operating under high pressure. Additionally, horizontal stops should be implemented to provide maximum isolation efficiency while allowing flexible movement. According to the installation guidelines from Oria, proper placement of safety stops can significantly extend the service life of the bellows by preventing excessive stretching or compression.
Tevema air bellows are integral components in high-pressure hydraulic systems due to their flexibility, high isolation capability, and maintenance-free operation. By replacing traditional rigid actuators with these pneumatic alternatives, industries can benefit from enhanced performance, reduced maintenance, and prolonged machinery life. From lifting mechanisms to vibration isolation, air bellows prove to be a versatile and reliable solution in demanding industrial environments.