Why Choose OMSS Sanitary Stainless Steel Union
- Have over 20 CNC machining centers, forging equipment and automated polishing lines, meeting various demands ranging from small-batch customization to large-scale procurement.
- Our stable CNC processing system ensures your dimensional consistency across every production batch, reducing on-site assembly errors and leakage risks.
- Provide sanitary stainless steel unions that comply with many standards such as DIN, SMS, 3A, convenient for you to switch between different equipment and market standards.
- Support customized production based on your equipment interface form, installation space, sealing structure or non-standard dimensions.
Reliable Sanitary Stainless Steel Union Supplier Partner
The appropriate sanitary stainless steel union is not merely a single connection piece. It is about choosing a long-term stable connection solution for your production line. Whether you are dealing with high-temperature steam sterilization, usually disassembled and cleaned CIP systems, or long-term erosion by corrosive media, OMSS can provide sanitary stainless steel unions that match your working conditions. If you are planning a new clean piping system or have questions about the selection of existing unions, please feel free to contact us at any time.
Types of Sanitary Stainless Steel Unions

Show a simple structure and uniform force distribution. Have low requirements for installation accuracy. It is a cost-effective choice, commonly used in food,and conventional pharmaceuticals.

With more concentrated contact pressure, they have stronger sealing performance. It is particularly suitable for pipelines with pressure fluctuations or temperature changes.

Locked by a Crescent Key clamp, and faster to disassemble and assemble than the traditional Union. This design can help you improve maintenance efficiency and require less space.

Both ends use butt-welded joints. With a smooth transition without dead corners, it is a common configuration for industries with high cleanliness requirements (such as sterile preparations).
Features of Sanitary Stainless Steel Unions

The flow channels of sanitary stainless steel union are continuous and smooth, with no threads, no gaps, and no retention areas inside. It can achieve complete emptying.

There is no need for welding or complex cutting. Installation can be completed manually or with a regular wrench, reducing your construction costs.

Sanitary stainless steel union’s structural design allows you for multiple disassemblies without affecting the sealing performance. The interface is not easy to deformation.

Its sealing surfaces are symmetrically loaded, less likely to be biased or shifted. It can still maintain stable sealing under temperature fluctuations or fluid impacts.

After acid pickling, passivation and electrolytic polishing treatment, a stable passivation film is formed on the union surface, which can run for a long time in the corrosive medium environment.

Compared with flange connection,sanitary stainless steel union has a smaller volume and lighter weight, making it suitable for clean workshops, exposed pipelines, and equipment interfaces.

The temperature resistance range is approximately -30℃ to 200℃, and it can withstand repeated sterilization with 121℃ high-pressure steam, suitable for food and pharmaceutical systems.

The sanitary stainless steel union’s surface is uniformly bright, and the welds and polishing are even. This helps you to enhance the overall appearance and equipment engineering image.
Customization Capability
OMSS can provide customized sanitary stainless steel unions, including sizes, non-standard structures or with special surface treatments based on your equipment interface and working conditions. These units support laser marking, OEM identification, special sealing component configuration, and can be made of 304,304L and 316L stainless steel materials to meet different cleanliness levels and corrosion resistance requirements.


Production Process
Our sanitary stainless steel unions are manufactured using automated forming and TIG automatic welding processes. It achieves smooth weld seams and the inner walls have no protrusions or welding slag. This could ensure continuous and smooth flow channels and avoid medium stagnation. This is particularly important for systems that require CIP/SIP cleaning verification, offering you less potential contamination points.
Full-process Quality Management
OMSS strictly implements full-process quality control, from raw material spectral analysis to size inspection, pressure testing and surface roughness testing. Key dimensions are 100% inspected during the CNC machining stage and monitored by thread gauges, calipers and three-coordinate measuring equipment to ensure that each sanitary stainless steel union provides you with stable interchangeability, sealing performance and batch consistency.

Applications of Sanitary Stainless Steel Unions

The detachable sanitary stainless steel union can help you quickly complete assembly and disassembly as well as cleaning, decreasing potential hygiene hazards. It is suitable for scenarios such as juice, dairy, seasoning, and beverage production lines. This keeps hygiene and safety while also improving your operational efficiency.

The pharmaceutical industry typically employs a metal-to-metal sealing structure of sanitary stainless steel union without gasket components. This completely eliminates the contamination risk caused by gasket aging. At the same time, the electrochemically polishing inner surface prevents bacteria from adhering. It is commonly used in the delivery pipelines of raw materials, injections, and infusion products.

The production lines for daily chemicals often require frequent changes for different formulas and they have high demands for equipment flexibility. By using sanitary stainless steel union, you can quickly adjust the pipeline structure without compromising the sealing performance. Moreover, the stainless steel material is resistant to various chemical corrosions, which helps to reduce maintenance frequency and spare part costs.
The semiconductor company has extremely strict requirements for the release of metal ions. It is common to adopt sanitary stainless steel union made from 316L material and treated with electrolytic polishing and passivation. It could significantly reduce the ion release risk and meet the demands for transporting high-purity gases or chemicals. Moreover, their removable design facilitates regular inspections and system maintenance.
- Certificate of Compliance
Customer Reviews
Yes. Compared to welding connections, the sanitary stainless steel union structure enables you to archive quick disassembly and assembly without damaging the pipeline, convenient for maintenance, equipment replacement or expansion of the pipeline. It is particularly useful for production lines that require regular cleaning or maintenance.
During routine maintenance, it is recommended for you to pay close attention to the sealing gasket’s wear. Because the sealing element is a key factor affecting the reliability of the connection. At the same time, you should also avoid excessive tightening to prevent damage to the sealing surface or metal deformation.
On production lines with CIP or SIP cleaning systems, please check the connection stability and sealing condition according to the verification cycle to ensure long-term operation without leak.
In actual engineering, the sanitary stainless steel unions’ failure is often not caused by material issues, but more related to selection and installation. For example, mismatch between the sealing material and the medium, excessive installation torque, or stress offset in the pipeline, can accelerate wear or cause leakage.
If your system has vibration, temperature fluctuations or requires frequent disassembly, it is advisable to confirm the matching of sealing materials, structural form and working conditions in the early project stage.
What is Sanitary Stainless Steel Union
Sanitary stainless steel union achieves sealing through axial compression. It is widely used in food, beverage, dairy, biopharmaceutical, and fine chemical pipeline systems.
Unlike ordinary pipe joints, it generates stable axial compressive force through the locking nut, making both ends of the joint press against the sealing gasket in the middle. This forms a sanitary sealing structure with no dead corners, no leakage, and easy cleaning.
Composition of Sanitary Stainless Steel Union
Nut
The nut is the unions’ core locking component and is usually in a hexagonal or octagonal shape which makes installation and disassembly on-site more quick and easy. It generates axial compression force by screwing into the female end, pulling the connecting components tight and compressing the sealing element. Generally, the nut material is the same as that of the pipe fitting, usually 304 or 316L stainless steel.
Welded Joint
The welded joint connects to the piping system. You can choose installation based on the project, including butt welding, socket welding or threaded method(such as NPT/BSP).
Welded Sleeve
The welded sleeve is installed at the other end of the pipe and provides an installation seat for the sealing element and forms a stable compression interface. High-quality sleeves should have precisely machined sealing surfaces and flat contact structures. So that they can deliver you with stable sealing performance after repeated assembly and disassembly and avoid frequent replacement of components.
Gasket
The sealing element is a key component for achieving zero leakage in the union joint and is pressed tightly between the sealing surfaces of the two ends of the joint. Common materials include silicone, fluororubber, polytetrafluoroethylene, and so on. And you can choose different sealing forms such as O-rings, flat washers, and custom-shaped special sealing rings.
What are The Differences between Sanitary Stainless Steel Union, Clamps and Flanges?
Clamps
The clamp realizes sealing by pressing the sealing gasket tightly with the clamp ring. It is generally locked by a single bolt or handle. Its greatest advantage lies in its extremely high disassembly efficiency, which can usually be completed within 30 seconds. Therefore, it is more common in systems that require frequent cleaning, maintenance, or replacement of pipe sections, such as food production lines, fermentation systems, or CIP cleaning pipe sections. If your system has a high maintenance frequency and requires quick disassembly and assembly, the clamp structure will be more suitable.
Flange
The flange seals the two end flange discs by pressing them tightly together with many bolts.
This structure has the strongest pressure-bearing capacity and the highest sealing redundancy. It is a more reliable choice for high-pressure, high-temperature, or long-term operation pipelines or steam lines or reaction equipment interfaces that do not require frequent disassembly.
Sanitary Stainless Steel Union
The sanitary stainless steel union generates axial compressive force through the locking nut, ensuring uniform force on the sealing element and achieving stable sealing. Compared to clamp connections, the union structure is more rigid and the connection is more compact. The internal flow channels usually do not show significant narrowing, so it is more suitable for use as equipment interfaces, valve connections, instrument interfaces, or pipe sections with limited space. When you need a connection with high stability and compact structure, sanitary stainless steel union is usually the better solution.
How to Choose Sanitary Stainless Steel Union
Standard
Different standards of stainless steel unions do not have compatible thread, sealing surface structure and dimensions. So first it is necessary to determine whether you need DIN, SMS, 3A, RJT or ISO. If not sure about the standard, you can also send us the pipeline’s outer diameter, thread specification and sealing surface diameter for measurement. We can deliver you precise matching solutions which could avoid installation failure or seal failure due to incorrect standards.
Material Medium
If your medium is fresh water or common food, 304 stainless steel union is a cost-effective choice for you. However, if the projects involve brine, strong acids, or strong bases, it is recommended to use 316L as your sanitary stainless steel union’s material.
Operating Condition
Temperature and sterilization methods are also very important considerations that determine the selection of your seals. For example, if your system is for ambient temperature media and does not require steam sterilization, a universal EPDM seal can be selected. If 121℃ steam sterilization (SIP) is required, a silicone seal is recommended. For higher temperatures or special chemical cleaning conditions, PTFE may be more suitable.
Frequency of Disassembly and Assembly
The frequency of disassembly and assembly will affect the choice of union structure. If your system requires frequent disassembly and cleaning or replacement of pipe sections, a clamp structure is more efficient.
If you need to achieve disassembly while maintaining rigidity and sealing stability, Sanitary Stainless Steel Union is a more reasonable solution.
Pressure Level
It is generally recommended to select a rated pressure of at least 1.5 times the maximum system working pressure to ensure safety redundancy. When the system pressure is lower than PN10, most standard sanitary stainless steel unions can meet the requirements. However, in pulsating pressure or high-temperature conditions, you need to prioritize the use of higher-grade materials and sealing solutions.
















