COMPACT
DN 50
PRESSURE BALANCED
(FINGER TYPE) COMPENSATORS FOR A RESEARCH CENTRE

For a research centre for fundamental science located in Germany, Belman has engineered and manufactured some highly compact DN 50 Pressure Balanced (Finger Type) Compensators with a built-in length of 299 mm. The Pressure Balanced (Finger Type) design ensures that the equipment is not pushed out of position, as this Expansion Joint design keeps the same length during operation.

 

The research centre*
The research centre focuses exclusively on civil and peaceful purposes. It operates particle accelerators used to investigate the structure, dynamics and function of matter, and conducts a broad spectrum of interdisciplinary scientific research in the following four main areas: particle and high energy physics; photon science; astroparticle physics; and the development, construction and operation of particle accelerators. The research centre employs more than 500 PhD students and postdocs and welcomes over 3000 guest scientists annually.
*Source: The website of the research centre

 

CLIENT ISSUE
In one section of the research centre, an optical table with vacuum chambers connects to vacuum pumps on a raised floor. Typically, the client would use stainless steel corrugated hoses for this connection; however, their engineers discovered that this solution was not durable, as the corrugated hoses contract when exposed to negative pressure, thereby transferring forces onto the vacuum chambers. To prevent this, the engineers at the research centre opted to replace the stainless steel corrugated hoses with Stainless Steel Pressure Balanced Expansion Joints. It is essential that the vacuum tanks in the application are not firmly connected to the table, but merely rest on it, as the optical setup in the tanks is so sensitive that any stress on the table would affect the alignment of the optics. The client therefore needed specially designed Expansion Joints capable of absorbing both axial and lateral movement to compensate for thermal expansion and external impacts on the frame structure, without transmitting these forces to the rigid structure connected to the compensators.

The research centre contacted Belman as they were looking for an Expansion Joint manufacturer that was not only capable of producing compact Inline Pressure Balanced Expansion Joints but also experienced with the critical applications in the research industry and thus familiar with their special requirements and needs.

 

BELMAN SOLUTION – Compact Pressure Balanced (Finger Type) Expansion Joint with a small diameter and ultra-short built-in length
To address the client’s issues and based on a dialogue with them and their specific needs, Belman engineered the Finger Type Pressure Balanced Expansion Joints, which are known for maintaining the same length under operation.

The Pressure Balanced Compensators are rigidly connected to the vacuum chamber on one side and to the impact protection surrounding the table on the other side. From there, the compensators are connected to the pumps via the usual corrugated hoses, allowing the frame structure to absorb the forces generated during pumping. This results in a primarily static setup.

 

The Pressure Balanced (Finger Type) design affords the client multiple advantages:

Inline Pressure Balanced Compensators that always maintain the same length
For the client, it was crucial that the Expansion Joint always maintains the same length, whether under pressure or not, to prevent the Expansion Joint from causing the frame structure to move. While a normal Expansion Joint would do that, thanks to its design, a Pressure Balanced Expansion Joint inherently stays the same length during operation, making it an ideal solution for this requirement.

Pressure Balanced (Finger Type) design is ideal for vacuum applications
The Pressure Balanced (Finger Type) Expansion Joint design was selected due to its internal limiters, making it particularly well-suited for vacuum applications. As the research centre operates under a vacuum, this was an excellent choice. Inline Pressure Balanced Expansion Joints are very good for vacuum applications as the finger design is especially suitable for this purpose.
Inline Pressure Balanced Expansion Joints are especially effective for vacuum environments
because they self-absorb forces and prevent any additional movement or load from being transferred to the connected equipment or piping system. This ensures stability and protects sensitive components from stress and forces.

Compact design – small size and ultra-short built-in length
Given the limited space at the installation point, it was essential to keep the Expansion Joint as short as possible. This required advanced engineering, which Belman expertly delivered, achieving a built-in length of just 299 mm. Additionally, the client requested a DN 50 size to ensure compatibility with the existing piping system, meeting both the spatial and technical requirements.

 

Belman – unparalleled experienced in Expansion Joints for research institutes and universities
Throughout the years, Belman has supplied numerous Piping Bellows for advanced technology applications across various research institutes and universities. Over the years we have helped many scientists, postdocs and PhD students by solving their complex movement accommodation issues. Besides design and manufacturing, Belman is frequently consulted by students and professors from prestigious technical universities for guidance on Expansion Joints for pilot and research projects, both within and beyond Europe. Given the complexity and precision required for such applications, every component, including the Expansion Joints, is expertly engineered and customised to meet the specific needs of each project.

 

Belman – a legacy of expertise in Expansion Joints of all sizes, from very small to very big
Since 1994 Belman has engineered over 900,000 Expansion Joints, demonstrating unmatched expertise in a wide range of sizes, designs and materials. This extensive experience spans both very small and very large sizes. Notable examples include a DN 40 Expansion Joint with a 120-mm built-in length for cryogenic application inside space rockets, and a giant 4-metre-long DN 2500 Finger Type Expansion Joint for a power and desalination plant. Additionally, Belman has designed and manufactured a Double Hinged Expansion Joint weighing 40 tonnes, demonstrating its ability to handle even the most demanding projects.