What Products are Involved?
Type-SR Inline Viscosity and Density meters (SRV and SRD)
What is the purpose of this article?
Detail the guidelines for installing Type-SR sensors in chocolatte lines.

TABLE OF CONTENTS

Introduction

Chocolate has long been a beloved treat, enjoyed by people worldwide in a variety of forms, from simple bars to elaborate confections. The chocolate industry itself is a massive global market, with billions of dollars in annual revenue, spanning from cacao cultivation to the final product that reaches consumers. As demand continues to rise, manufacturers must meet high standards for both quality and efficiency. This is where the intricate process of chocolate manufacturing comes into play, where sophisticated machinery and piping systems are essential to streamline production. These systems help ensure the smooth flow of ingredients, maintain consistent texture, and optimize the mass production of chocolate products, playing a vital role in shaping the final result.


Read: High quality Swiss chocolates rely on in-line viscosity monitoring for consistent rheology & texture » rheonics :: viscometer and density meter 


Figure 1: Industrial chocolate enrobing and cooling line

Figure 1: Industrial chocolate enrobing and cooling line


Rheonics Inline Density and Viscosity sensors

Rheonics provides inline sensors for measuring viscosity and density, enabling comprehensive automation of chocolate manufacturing and handling.

The Rheonics SRV sensor measures viscosity and temperature, whereas the SRD sensor measures density, viscosity, and temperature simultaneously. Both sensors are designed to operate accurately in various environments, delivering consistent and reliable results.

These Type-SR sensors offer users the following benefits:

  • Continuous inline monitoring of viscosity and density during chocolate mixing and coating processes.

  • Zero recalibration is needed throughout the sensor's lifespan.

  • Reduce waste by removing sampling and measurement delays

  • High precision and repeatability

  • Enhanced potential for complete process automation.


Figure 2: Rheonics SRV (left) and SRD (right) 2” Tri-Clamp long insertion probes

Figure 2: Rheonics SRV (left) and SRD (right) 2” Tri-Clamp long insertion probes

Challenges

With chocolate, we found that if the sensor was installed perpendicular to the flow and operation temperatures were near the melting point of the chocolate, crystallization would occur, leading to the formation of a beard on the side of the resonator that is not directly facing the flow. This led to a progressive drift in the measurement, which negatively affected monitoring and control operations. To solve this, an installation with the sensor probe parallel or axial to the fluid flow is highly recommended. 

Crystal formation happens at low temperatures (around 27 °C), meaning the recommendations explored are only valid when this phenomenon is known to take place. Many operations, such as enrobing, do not have crystal formation as the chocolate is handled at high temperatures.

Typically, most chocolate manufacturing processes involve grinding and mixing the ingredients in a mixing tank or conch until the desired viscosity and texture are achieved. This chocolate mass is then moved to a holding tank before passing to more specialized devices such as tempering and forming machines.


Figure 3: Process flow diagram for a chocolate molding machine. Ingredients are combined into a mixing tank until the desired properties are reached, then it is transported to a holding tank before moving towards a tempering and molding machine.

Figure 3: Process flow diagram for a chocolate molding machine. Ingredients are combined into a mixing tank until the desired properties are reached, then it is transported to a holding tank before moving towards a tempering and molding machine.

Online viscometers to monitor and optimize process in chocolate production

Viscosity is a critical parameter in the production of chocolate. Properly monitoring this property allows manufacturers to have control over characteristics such as texture, taste, and moisture content, as well as assisting them in processes like enrobing or tempering. In this way, online viscometers can be applied to several processes throughout confections that involve chocolate.

Monitoring of conching process

Chocolate conching is a process where chocolate mass is continuously mixed and ground to improve its texture and flavor. It reduces particle size, removes unwanted flavors, and enhances the aroma and color of the chocolate. The process also helps eliminate excess moisture, improving shelf life.

The SRV online process viscometer can be used to measure the viscosity of chocolate during the conching process. This helps ensure the chocolate has the right viscosity for tempering and enrobing. 


Figure 4: Netzsch’s Confectionery Systems - System Rumba® - Highly Efficient Chocolate Production

Figure 4: Netzsch’s Confectionery Systems - System Rumba® - Highly Efficient Chocolate Production


Overview of the conching process 

The chocolate conching process involves the following steps:

  1. Grinding and Mixing: Chocolate mass is continuously stirred and ground to break down cocoa particles.

  2. Flavor Development: The process eliminates undesirable flavors and enhances the chocolate's taste and aroma.

  3. Moisture Removal: Conching reduces excess moisture, improving texture and shelf life.

  4. Fine-Tuning: Duration and machine type can vary, affecting the final product's smoothness and quality.


Figure 5: Process flow diagram of HCC line of conching machines by ContinousChone

Figure 5: Process flow diagram of HCC line of conching machines by ContinousChone  


Integrating Inline Viscometer to a chocolate conching process:

Installing in the conch may not always be possible as there may be no space for the SRV sensing element to stick into the mixing chamber. When this is the case, an installation can take place in the conch’s recirculation line. An example of this can be seen in the image below, with an SRV installed in the conch’s recirculation line due to the space restrictions inside the mixing tank.


Figure 6: Process flow diagram of an SRV for viscosity monitoring in the recirculation line of a chocolate conching machine.

Figure 6: Process flow diagram of an SRV for viscosity monitoring in the recirculation line of a chocolate conching machine.


Monitoring of chocolate mass and glaze: 

Monitoring chocolate mass and glaze is essential to ensure consistent quality and texture throughout the production process. Parameters such as temperature, viscosity, particle size, and moisture content are carefully controlled to maintain the desired smoothness and shine. Regular checks and adjustments help optimize the flow properties and prevent defects, ensuring the final product meets both taste and appearance standards. 

The SRV online process viscometer can be used to monitor whether the processed chocolate mass has the right consistency for filling, enrobing, and shell making


Figure 7: The SRV Inline Viscometer installed before the mold filling head helps ensure the correct viscosity right before molding.

Figure 7: The SRV Inline Viscometer installed before the mold filling head helps ensure the correct viscosity right before molding.


Lines used for these processes usually employ piping between 2” and 4”. These are generally jacketed as they help maintain the temperature uniformity of the flowing chocolate mass throughout the process. Installing the SRV in these lines is explored in the next section.

Installation guidelines for Rheonics' inline solutions

In general, the guidelines presented are considered with the following goals in mind:

  • Achieve a robust and reliable installation of Rheonics viscosity and density meters

  • Comply with the hygienic requirements imposed by the chocolate industry.

  • Handle the challenges presented by the nature of the fluid at different operating conditions.


Note: Rheonics SRV and SRD sensors can be ordered with a Hygienic Certification (3-A or EHEDG).


In this way, when operating at temperatures near the chocolate’s glass transition point, Rheonics recommends opting for:


Elbow installation

Installing the Type-SR probes in an elbow configuration is highly recommended as it helps reduce the possibility of the sensor probe fouling due to the crystallization of the chocolate. When installing these sensors, it is recommended they be installed against fluid flow, as shown in the picture below. This improves the cleanability of the sensor as the sensing element will be constantly exposed to flowing fluid, which will contribute to the removal of any possible residues or solidification. 


Figure 4: Installation of an SRV-XD long insertion probe in a double-jacketed elbow using a DIN 11852 process connection.

Figure 8: Installation of an SRV-XD long insertion probe in a double-jacketed elbow using a DIN 11852 process connection.


A jacketed tee connection, as shown in Figure 4, can be paired up with an appropriate process connection, such as Tri-Clamp or DIN 11852, making the entire installation sanitary and hygienic compliant. Alternatively, if a jacketed pipe is not required, one can opt for Rheonics' inline flow cells (FET-XXT) for a cleaner elbow installation, helping reduce the possibility of fluid buildup around the probe or shoulder area.

In terms of probe variants, it is recommended to opt for the X5-Long insertion probe (SRV/SRD) as it helps move the sensing element away from possible low circulation zones and into the center of fluid flow. This recommendation is stressed if the operation involves high-temperature chocolate (at least 15°C above room temperature) alongside an SRD. See thermal balance requirements for SRD probes.

Nonetheless, if temperatures are near ambient and the selected probe type is SRV, the SRV-X3-Tri-Clamp variant can be used alongside the FET line of flow elbow cells. 


Figure 5: SRV-HS-X3-15T installed in an FET-20T-20T flow elbow cell

Figure 9: SRV-HS-X3-15T installed in an FET-20T-20T flow elbow cell


Installing StarGate inline

When installations in elbows are not possible, one can opt to use Rheonics' Stargate probe variant. This design places the sensing element in the middle of the flow of fluid, making it robust against fouling and fluid buildup. Currently, Rheonics offers the Stargate in a standard DN50 size and the necessary information for the manufacture of matching adapters.


Figure 6: SRV-X6-SG - Stargate probe for inline viscosity measurement

Figure 10: SRV-X6-SG - Stargate probe for inline viscosity measurement


Perpendicular inline install

If fluid is known to operate above its melting point (usually above 27°C), then a perpendicular installation is recommended. Here, multiple installation alternatives are possible based on line size, however, the most common solution involves using either an X3 or X5 probe (based on line size) to place the sensing element in the center of the fluid flow.


Figure 7: Inline installation of WFT-15T for Type-SR X3/X5-15T probes

Figure 11: Inline installation of WFT-15T for Type-SR X3/X5-15T probes


To achieve this, one can use the WFT-15T in order to create an access port for a Type-SR X3/X5-15T sensor probe. Alternatively, one could also opt towards using Rheonics' Clamped flow tee spool piece (FTP) and install the sensor in the built-in Tri-Clamp connection.


Figure 8: Clamped flow tee spool piece (FTP) for Tri-Clamp Type-SR sensor probes.

Figure 12: Clamped flow tee spool piece (FTP) for Tri-Clamp Type-SR sensor probes.


Moreover, one other alternative is to opt for a Varinline flange, which is compatible with DN50 and DN80 pipe sizes. A more detailed overview on how to achieve this style of installation can be explored in the following articles:

Finally, one other alternative involves using the X1-12G probe variant alongside the HAW-12G-OTK weldolet. This alternative is ideal for small lines (2.5” to 3”) and provides the benefits of a hygienic installation in a small form factor.


Figure 9: Installation of Type-SR X1-12G sensor probes in a tank or pipe wall using an HAW-12G-OTK2.

Figure 13: Installation of Type-SR X1-12G sensor probes in a tank or pipe wall using an HAW-12G-OTK2.


Tank installation

For tanks, the Type-SR X1-12G probes can be installed using the already mentioned HAW-12G-OTK in walls up to 10 mm, however, the recommended probe variant is the Type-SR X4 - Flush probe (SRV/SRD). 

These can use a Tri-Clamp connection to mount the viscometer in a flush installation, meaning that the dead zones are partially or completely removed depending on the type of installation or accessory used. The probe's hygienic design and possible hygienic certification, along with the removal of dead zones, make the probe easier to clean and disinfect with standard procedures (e.g., Clean in Place - CIP). 


Figure 10. Exploded view of assembly example with TC flush flange

Figure 14. Exploded view of assembly example with TC flush flange


Key aspect and benefits of using the SRV online process viscometer for inline installation - built for hygienic installs:

Performance & Accuracy:

  • Continuous, Reliable, and Accurate Measurement: Provides real-time viscosity data, crucial for process control.

  • High Sensitivity and Repeatability: Ensures precise and consistent readings.

  • Immunity to Process Variations: Unaffected by fluid condition changes, stirrers, agitators, flow rate variations, bubbles, or solid particles.

  • High Immunity to External Vibration: Designed to maintain accurate readings despite plant noise and vibration.

  • Factory Calibration: Calibrated with NIST-traceable standards, eliminating the need for field calibration.

Construction & Durability:

  • Robust Design: Field-proven device, designed to withstand harsh industrial environments.

  • 316 Stainless Steel Construction: All-welded, clean-in-place, and capable of withstanding hostile process conditions.

Hygienic Design: 

Crevice-free design minimizes fouling and material entrapment. Certified to EHEDG and 3-A sanitary standards.

  • Versatile Mounting: Suitable for pipe or tank mounting in any orientation.

  • Sanitary Fittings: Available with various sanitary fittings, including quick-release tri-clamp, RJT (Ring Joint Type), IDF (International Dairy Federation), ASME, ANSI, JIS, DIN, ISO.

IP Rating:

  • Designed with high IP ratings to protect the device from dust and water ingress, ensuring reliable operation in harsh industrial environments.

Operational & Maintenance:

  • Low Maintenance: No moving parts, seals, or bearings, resulting in minimal maintenance requirements and low life-cycle costs.

  • In-field and Remote Readout: On-sensor display as well as remote electronics and interface unit.

Output & Communication:

  • Analog Output: 4-20 mA analogue viscosity signal.

Multiple Industrial Communication Protocols:

  • HART

  • Modbus TCP

  • EtherNet/IP

  • Profinet

  • And other industrial communication options.

  • Ethernet capabilities.

  • Capabilities for connection to IOT platforms and cloud connectivity. Direct support for IOT platforms like Ignition and ThingWorx.

  • Capabilities for connection to almost all major PLC and IPC systems.

  • This allows for seamless integration into a wide range of industrial automation systems.


In essence:

The SRV online process viscometer is designed for industrial applications requiring reliable and continuous viscosity monitoring. Its robust, hygienic, and low-maintenance design, coupled with its high accuracy and immunity to process variations, makes it a valuable tool for process control and quality assurance. The sensor can be placed in hostile environments, and the data can be read remotely.  

Learn More about the SRV - Inline Process Viscometer

  • SRV page - Discover and learn how to order the SRV - Inline Process Viscometer


Figure 11: Rheonics SRV-X1-34N Inline Process Viscometer sensor variant

Figure 15: Rheonics SRV-X1-34N Inline Process Viscometer sensor variant



Figure 12: Rheonics SRV-X5-APC - Adaptable Process Connection Inline Process Viscometer sensor variant

Figure 16: Rheonics SRV-X5-APC - Adaptable Process Connection Inline Process Viscometer sensor variant



Figure 13: Rheonics SRV-X4-VN Flush Inline Process Viscometer sensor variant

Figure 17: Rheonics SRV-X4-VN Flush Inline Process Viscometer sensor variant


Key Players in the Chocolate Industry

Major Chocolate Manufacturers:

  • Barry Callebaut: A global leader in chocolate and cocoa products, providing high-quality ingredients to manufacturers. Link to their website

  • Frey: A Swiss chocolate manufacturer known for premium chocolate products. Link to their website

  • Mars: Famous for its iconic candy and chocolate products, including Mars, Snickers, and M&M's. Link to their website

  • Hershey's: Renowned for its chocolate bars and other confectionery products. Link to their website

Major Equipment Suppliers:

  • Bühler: A leading supplier of food processing equipment, including chocolate production systems. Link to their website

  • Netzsch: A global supplier of milling and dispersing equipment, including for chocolate production. Link to their website

  • Gusu: Specializes in chocolate and candy processing equipment. Link to their website

  • Vekamaf: Provides machinery solutions for the chocolate and candy industries. Link to their website

Major Brands: