What is the purpose of this article?
Provide an overview and concepts of the main hygienic coupling types used in the industry and their compatibility with the Rheonics SRV sensor.

What products are involved?
SRV - Inline Viscosity Meter

TABLE OF CONTENTS

• Introduction
• Rheonics SRV Overview
• Overview of Hygienic Coupling Types
  • Tri-Clamp couplings
  • DIN11851 Couplings
  • SMS Couplings
  • RJT Couplings
  • IDF Couplings
• Conclusion
• References

Introduction

Sanitary process industries depend on hygienic couplings to ensure cleanable, leak-free, and contamination-free connections between instrumentation and equipment. In industries like food & beverage and pharmaceutical, maintaining strict hygiene standards is mandatory, so following sanitary compliances is essential for their processes. Selecting appropriate couplings directly impacts process integrity to follow sanitary regulations, and ease of maintenance and cleaning operations like CIP (Clean-in-Place) and SIP (Sterilize-in-Place).

This article provides an overview of the main hygienic couplings available to use with Rheonics SRV sensors, designed for real-time monitoring of viscosity, density, and temperature used in a wide range of sanitary applications.

Rheonics SRV Overview

The Rheonics sensor SRV measures viscosity and temperature in line for real-time process control and monitoring.

The SRV is factory calibrated and does not need recalibration over its operational lifetime. However, clients may require calibration or verification for instruments used in their industry as part of their Quality Control. Optional re-adjustments or offset corrections can be performed if needed to match specific references. For more details, see Calibration of inline process viscometer SRV in field and factory.

Rheonics sensors technology is based on a balanced torsional resonator (BTR). The patented BTR technology has a significant advantage over competitors since it allows the sensors to be compact, lightweight, and unaffected by external vibrations.

The SRV is well suited for hygienic applications where viscosity is a critical process parameter. For example, in the personal care market (i.e., shampoos, liquid soap, and lotions production) and the food & beverage industry (i.e., milk, glazes, sauces, and even aerated or foamy liquids production) a precise control is required to ensure product uniformity, consistency, and quality compliance. 

By default, the SRV features a hygienic design, and if required, it can be provided with a hygienic certification upon request. Its sanitary and versatile modular construction makes it easy to achieve integration into applications where hygiene compliance is required.

Figure 1 - Rheonics SRV sensor: Versatility for hygienic installation options

Overview of Hygienic Coupling Types

Hygienic coupling or unions are designed to follow sanitary compliances in sanitary process systems. Their design ensures that no product residue is trapped at the connection points, which is essential in maintaining sterility and process integrity, especially during Clean-in-Place (CIP) and Sterilize-in-Place (SIP) procedures.

As mentioned before, SRV probes come with a hygienic design by default, making them suitable for sanitary applications. If needed, probes can also be supplied with hygienic certification. There is no universal standard for hygienic couplings, as different industries and regions favor specific connection types. However, most followed guidelines from recognized organizations, such as EHEDG and 3-A, are available for Rheonics SR sensors.

Figure 2 - Hygienic certifications available for Rheonics Sensors

For more details, visit Rheonics hygienic and sanitary installation

Rheonics offers a wide range of industrial process connection options to ensure compatibility. The most commonly used hygienic couplings compatible with the Rheonics SRV sensor include:

Tri-Clamp couplings

Tri-Clamp (also known as Tri-Clover or Tri-Ferrule) couplings are among the most popular hygienic connections, known for their simple assembly and ease of cleaning. These couplings are widely used in the food, beverage, and pharmaceutical industries due to their fast disassembly and compatibility with a broad range of equipment.

These consist of two identical ferrules, a hinged clamp ring, and a seal ring. Tri-Clamp connections are compatible with several tubing standards, including DIN 11850, EN 10357, ASME-BPE, BS 4825, ISO 2037, and ISO 1127, allowing easy integration into hygienic piping systems.

Their proven performance and versatility make Tri-Clamp couplings a preferred choice in dairy, breweries, pharmaceuticals, cosmetics, food and beverage, and biotech industries.

Components:

• Two identical ferrules
• Hinged clamp ring
• Seal ring

Figure 3 - Tri-Clamp Coupling Pipe connection [1]

How to create an ordering code:

Sizes available:

Review Tri-Clamp sizes compatibility with Rheonics sensors

• 15T / B15T - 50.5 compatible with DN32 DN25 (ISO 1127), DN25 DN32 DN40 (DIN32676), 1.5” (ASME-BPE)
• 20T / B20T - 64 compatible with DN32 DN40 (ISO 1127), DN50 (DIN32676), 2” (ASME-BPE)
• 25T / B25T - 75 compatible with DN50 (ISO 1127), 2 1/2” (ASME-BPE)
• 30T / B30T - 91 compatible with DN65 (ISO 1127), DN65 (DIN32676), 3” (ASME-BPE)

Note: Larger sizes are also available. For more information or custom configurations, please contact our support team.

Example:

Description: Short probe variant of the SRV inline process viscometer, hygienic design without certification, and Tri-Clamp (50.5 mm) process connection.

Figure 4 - SRV-HD-X3-15T: Short Probe with Tri Clamp coupling

DIN11851 Couplings

DIN 11851 unions, commonly known as dairy or milk couplings, are hygienic fittings widely used for connecting process lines in sanitary industries. They are characterized by their threaded connection and D-shaped seal, which ensures reliable performance and easy maintenance.

DIN 11851 unions conform to the DIN 11850 tube standard, making them compatible with many hygienic piping systems. Their high-quality stainless steel construction and popularity in regions like Western Europe make them a reliable choice for food, beverage, and pharmaceutical applications.

Components:

• Male threaded part
• D-shaped Seal ring
• Liner
• Round slotted nut

Figure 5 - DIN11851 Coupling Pipe connection [1]

How to create an ordering code:

Sizes available:

• BH32: DN32
• BH40: DN40
• BH50: DN50
• BH65: DN65

Note: Larger sizes are also available. For more information or custom configurations, please contact our support team.

Example: 

Description: Short probe variant of the SRV inline process viscometer, hygienic design without certification, and DIN11851 DN40 process connection.

Figure 6 - SRV-HD-X2-BH40: Short probe with DIN11851 coupling

SMS Couplings

SMS (Swedish Manufacturing Standard) unions are widely used hygienic fittings designed for connecting process lines in sanitary industries. While they share similar application fields with DIN 11851 unions, SMS unions are distinguishable by their unique mechanical and sealing design.

SMS unions are also compatible with tube standards like BS 4825 and ISO 2037, ensuring easy integration into hygienic piping systems. Their availability in regions where DIN standards prevail, such as Europe and parts of Latin America, increases their accessibility and ease of use in existing setups.

Components:

• Male threaded part
• Square-shaped Seal ring
• Liner
• Round slotted nut

Figure 7 - SMS Coupling Pipe connection [1]

How to create an ordering code:

Sizes available:

• BS15: 1.5”
• BS20: 2”
• BS25: 2.5”
• BS30: 3”
• BS40: 4”

Note: Larger sizes are also available. For more information or custom configurations, please contact our support team.

Example:

Description: Short probe variant of the SRV inline process viscometer, hygienic design without certification, and SMS 1.5” process connection.

Figure 8 - SRV-HD-X2-BS15: Short probe with SMS coupling

RJT Couplings

RJT (Ring Joint Type) unions are hygienic fittings commonly used in the UK and globally for sanitary process connections. Its simple but robust design featuring a male threaded part, pressed liner, hexagon nut, and O-ring seal ensures a secure and leak-resistant connection in demanding sanitary applications.

Known for their reliability and ease of maintenance, RJT unions allow for quick assembly and disassembly, minimizing downtime during cleaning or part replacement. They are also compatible with BS 4825 and ISO 2037 tubing standards, making them a practical choice for hygienic systems requiring efficiency and consistent performance.

Components:

• Male threaded part
• O-shaped Seal ring
• Liner
• Hexagon nut
  

Figure 9 - RJT Coupling Pipe connection [1]

How to create an ordering code:

Sizes available:

• BR15: 1.5”
• BR20: 2”
• BR25: 2.5”
• BR30: 3”
• BR40: 4”

Note: Larger sizes are also available. For more information or custom configurations, please contact our support team.

Example: 

Description: Short probe variant of the SRV inline process viscometer, hygienic design without certification, and RJT 1.5” process connection.

Figure 10 - SRV-HD-X2-BR15: Short probe with RJT coupling

IDF Couplings

IDF (International Dairy Federation) unions provide reliable hygienic connections primarily in dairy, brewery, and pharmaceutical industries where strict hygiene standards are essential. Their design includes a male threaded part, liner, nut, and seal, all built to also meet standards BS 4825 and ISO 2037. 

Though less common than other union types, IDF couplings are valued for their dependable performance in applications demanding high reliability and cleanliness. Their specialized construction makes them a trusted choice for maintaining system integrity in environments with uncompromising hygiene requirements.

Components:

• Male threaded part
• T-shaped Seal ring
• Liner
• Hexagon nut

Figure 11 - IDF Coupling Pipe connection [1]

How to create an ordering code:

Sizes available:

• BI15: 1.5”
• BI20: 2”
• BI25: 2.5”
• BI30: 3”
• BI40: 4”

Note: Larger sizes are also available. For more information or custom configurations, please contact our support team.

Example:

Description: Short probe variant of the SRV inline process viscometer, hygienic design without certification, and IDF 1.5” process connection.

Figure 12 - SRV-HD-X2-BI15: Short probe with IDF coupling

Conclusion

Selecting the proper hygienic coupling is crucial for maintaining process integrity, ensuring cleanliness, and complying with industry standards in sanitary processes. Each Tri-Clamp, DIN 11851, SMS, RJT, and IDF has distinct properties to consider.

Rheonics SRV sensor features process connections that accept all these sanitary coupling designs, getting great flexibility and enabling plug-in integration into any sanitary system without requiring major piping modifications.

References

[1] Sanitary Fittings CAD, “The 6 connection types for sanitary tubes”. https://www.sanitaryfittings-cad.com/Articles/The-6-connection-types-for-sanitary-tubes