Pipe unions – find manufacturers and suppliers

Pipe unions are mechanical connections that are used to join pipes or hoses together or to connect them to devices.

They enable tight connections in piping systems and are designed to withstand high pressures and temperatures.

Below you will find the main types of tube fittings, the materials used and their applications:

Main types of pipe unions:

There are different types of pipe unions, which are selected depending on the application and the materials to be used. Here are the most common types:

1. Screw-in fittings: These fittings are screwed directly into a thread on the pipe or on an appliance. They have an external thread and fit into an internal thread to create a tight connection.
   Use: Commonly used in hydraulic and pneumatic systems as well as in gas and water installations.
2. Cutting ring fittings consist of three main parts: The fitting body, a cutting ring and a union nut. When the nut is tightened, the cutting ring presses into the pipe, ensuring a tight and firm connection.
   Application: Primarily in hydraulic systems, especially in high-pressure applications. Cutting ring fittings offer a high level of safety and are leak-free.
3. Flare fittings: These fittings are used when pipes are flared (flanged) at their end. A conical sealing surface provides the seal, while a union nut presses the pipe against the fitting.
   Use: Mainly in applications where gas or liquid is transported under high pressure, e.g. in refrigeration technology or heating systems.
4. Compression fittings: Compression fittings become tight by pressing a clamping element, such as a seal or a ring, against the pipe. The pipe is fixed and sealed by tightening the union nut.
   Application: Commonly used in water installations, e.g. for copper pipes or flexible plastic pipes.
5. O-ring fittings: These fittings use an O-ring for sealing. The O-ring sits in a groove in the fitting body and seals the system when the union nut is tightened.
   Use: In hydraulic systems and applications where a reliable and tight connection is essential.
6. Weld fittings: These fittings are connected directly to the pipe by welding. After welding, the fitting ensures a tight and mechanically stable connection.
   Application: For permanent pipe connections that have to withstand high pressures and temperatures, such as in chemical plants or power stations.
7. Cone fittings (BSP, NPT): These fittings have a conical thread that cuts more and more firmly into the mating part as it is tightened. This creates a tight connection.
   BSP (British Standard Pipe): A widely used standard in Europe for pipe unions with a metric thread profile.
   NPT (National Pipe Thread): A standard widely used in the USA in which the thread is tapered.
   Use: For piping applications in the oil and gas industry, water installations and in compressed air systems.
8. Fittings for flexible pipes and hoses: These fittings are specially developed for flexible pipes and hoses. They clamp the pipe or hose using a union nut or clamping system to ensure a tight connection.
   Application: In many areas of industry, e.g. for compressed air and hydraulic systems.

Materials of pipe unions:

Choosing the right material for pipe unions depends on the conditions of use, particularly the type of medium, temperature and pressure. Common materials are:

• Stainless steel: Highly corrosion-resistant and resistant to high temperatures and pressures. Suitable for aggressive media such as chemicals, salt water or high-temperature applications.
• Brass: Corrosion-resistant and conductive. Often used in water installations or for non-aggressive liquids and gases.
• Carbon steel: Resistant to high pressure, but not as corrosion-resistant as stainless steel.
• Plastics (e.g. PVC, PE): Lightweight, corrosion-resistant, but not suitable for high-pressure or high-temperature applications. Often used in water installations and sewage systems.
• Copper: Widely used in water pipes, especially in building services and heating systems.

Applications of pipe unions :

Pipe unions are used in a variety of industries and applications:

1. Water and gas supply:
Pipe unions are used to ensure that pipes in domestic and industrial installations are tightly connected. This includes water pipes, gas pipes and heating systems.

2. Oil and gas industry:
In this industry, fittings are exposed to high pressure and often aggressive media. High-pressure fittings made of robust materials such as stainless steel or carbon steel are used here in particular.

3. Chemical industry:
In chemical plants, pipe unions must be resistant to aggressive chemicals. Stainless steel and special plastics such as PTFE are often used for these purposes.

4. Hydraulic systems:
In hydraulic systems that operate under high pressure, fittings are essential to prevent leaks. Cutting ring fittings and O-ring fittings are often used.

5. Pneumatic systems:
Compression fittings or quick connectors for hoses and tubes are often used in compressed air systems.

6. Automotive industry:
Here, fittings are used in fuel, brake and hydraulic systems to ensure secure connections.

Pipe unions are indispensable in many industrial and technical areas. Their main task is to connect piping systems securely and tightly, whereby the choice of the right type and material depends on the specific requirements of the application. Whether for high-pressure systems, aggressive media or corrosive environments - there is a suitable tube fitting for every requirement.

Here is an overview of the most important points to consider when purchasing pipe unions :

When buying pipe unions , there are some important factors to consider to ensure that the fittings meet the requirements of the particular piping system. The correct selection depends on the type of medium, the operating conditions (such as pressure and temperature), the pipe materials used and the applicable standards.

• The material of the pipe fitting must be compatible with the properties of the medium (e.g. liquids, gases, chemicals) and the ambient conditions. The most common materials are
• Stainless steel: High corrosion resistance, ideal for aggressive media and harsh environments (chemical, offshore, food industry).
• Brass: Corrosion resistant and durable, often used in water installations and for non-aggressive liquids and gases.
• Carbon steel: High strength and pressure resistance, but less corrosion resistant. Suitable for applications in hydraulic systems and industrial plants.
• Plastic (e.g. PVC, PE): Lightweight and corrosion-resistant, but not suitable for high-pressure applications. Commonly used in water installations and sewage systems.
• Copper: Often used in water pipes and heating installations. Corrosion-resistant and durable, especially for drinking water installations.
• Depending on the type of piping system and the connection requirements, there are different types of pipe unions. Choose the type that meets the technical requirements and ease of maintenance:
• Cutting ring fittings: For tight connections, especially in high-pressure systems (hydraulics, pneumatics).
• Flare fittings: For pipes with flared ends, frequently used in refrigeration technology and gas lines.
• Compression fittings: Easy to install, widely used in water and sanitary installations.
• O-ring fittings: Good seal, common in hydraulic systems.
• Weld fittings: Durable connection, suitable for high pressure and high temperature applications.
• The fitting must be compatible with the pipe material used (e.g. stainless steel, copper, plastic). For example, there must be no corrosive reactions between the fitting and the pipe material.
• The size of the fitting must match the pipe size. Pay attention to the diameter of the pipe (outer and inner diameter) and the wall thickness requirements. It is important that the connection is an exact fit to ensure a secure and tight connection.
• Fittings must be able to withstand the operating pressure and operating temperatures of the system. Pay attention to the following specifications:
• Fittings are designed for different pressure ranges depending on the type and material. Hydraulic fittings for high-pressure systems must be extremely pressure-resistant, while fittings for water installations meet lower pressure requirements.
• Some materials, such as stainless steel, are suitable for high temperatures, while others, such as plastics, are only designed for low to moderate temperature applications.
• Tightness is a crucial factor when purchasing pipe unions to prevent leaks:
• Cutting ring and O-ring fittings offer excellent sealing characteristics that are reliable even at high pressures and temperatures.
• Compression fittings or compression fittings are easier to install but may not offer the same sealing performance as welded or threaded connections.
• Check whether additional sealants or Teflon tapes are required to seal the connection optimally.
• It is important to ensure that the pipe unions comply with international or national norms and standards to ensure compatibility and safety. The most important standards include:
• DIN/EN standards: Widely used in Europe and guarantee uniform specifications.
• ISO standards: Internationally standardized screw fittings.
• ANSI/ASME: Common standards in the USA.
• BSP (British Standard Pipe) and NPT (National Pipe Thread): Thread standards for pipe unions.
• Corrosion resistance is particularly important in areas that are exposed to aggressive environments, such as the chemical industry, offshore technology or outdoor applications. Stainless steel fittings are particularly suitable for such environments. In less corrosive environments, materials such as brass or carbon steel may be sufficient.
• Consider how easy the fittings are to install and maintain. Some tube fittings are easy to install and require few tools, while others, such as weld fittings, require expertise and specialized equipment.
• The price of tube fittings varies depending on the material, type and manufacturer. High-quality materials such as stainless steel are more expensive than plastic or carbon steel, but offer longer life and better corrosion resistance.
• Consider whether you want a long-term durable solution with a higher initial investment (e.g. stainless steel) or whether cheaper alternatives will suffice.
• Pay attention to the availability of the required fittings. It is advisable to choose common fittings that can be easily reordered to avoid downtime during maintenance.
• Look for certificates that confirm compliance with the relevant standards.

When purchasing pipe unions, it is crucial to carefully consider the specific requirements of the piping system, such as pressure, temperature, medium and pipe material. The right choice of fitting ensures a secure, durable and tight connection. Make sure that the material is corrosion-resistant and suitable for the operating conditions, and choose fittings that comply with the applicable standards to ensure maximum safety and functionality.

Pipe unions can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Pipe unions from all over the world can be found on Exportpages.