Rheonics Support

What is the purpose of this article?
Show guidelines on how to use the Rheonics SR- Type sensors in applications that involve trays. This article tackles installation requirements, and application limitations and lists recommended accessories for each use case 

What products are involved in this article?
SRV - Inline Viscosity Meter and SRD - Inline Density and Viscosity Meter

TABLE OF CONTENTS

• Installing Density and Viscosity sensors in trays
• Installation requirements
  • SRV Inline Viscometer Installation in Tray
  • SRD Inline Density and Viscosity Meter Installation in Tray
• Effects of vibration, shallow trays, and temperature stability

Installing Density and Viscosity sensors in trays

The use of trays in the industry is a common practice, particularly in applications such as coating with paints, inks, and in the pharmaceutical industry. Rheonis sensors can be installed in shallow trays, enabling inline density and viscosity readings of the fluid. How and when this can be achieved will be explored in this article.

Installation requirements

The Type-SR sensors require a minimum clearance around the sensing element called the sensing area.  This zone surrounds the sensing element and must only contain the fluid under measurement. In this way, fluid in this area is the most critical requirement when it comes to installing these sensors in trays. Below, the sensing zones are shown.

To use the Type-SR sensor probes in trays, an installation from the side is recommended. Due to the difference in sensing zones, installation requirements vary depending on the type used.

SRV Inline Viscometer Installation in Tray

The Rheonics SRV is used for inline measurement of dynamic viscosity and temperature. Here, the short SRV probe can be used. Review all SRV variants here: SRV Variants

Rheonics offers the SRV short probe with standard connections:: NPT 3/4”, G1/2, and Tri-Clamps at different sizes (eg. 1.5”). Custom connections are available under request. Each of these requires their respective port to be installed on the side of a tray, Rheonics offers suitable installation accessories as shown in the table below. Correctly placing this port is crucial for the correct operation of the sensor. For the SRV, the longitudinal axis of the sensor must sit at a distance of at least 8 mm from the bottom of the tray. Likewise, the tray must contain enough fluid to exceed the sensor's longitudinal axis by at least 8 mm. An example of a correct installation can be seen below for a G 1/2” process connection.

In short, it is recommended to install the SRV in trays where fluid has a depth of at least 16 mm. The problems that arise when omitting this recommendation will be explored later in this article.

Table 1: Recommended accessories for SRV installation in Tray

SRD Inline Density and Viscosity Meter Installation in Tray

Rheonics SRD measures the density, dynamic and kinematic viscosity, and temperature of a fluid. Here, the short SRD probe can be used, Review all SRD variants here: SRD Variants

Rheonics offers the SRD short probe with standard connections: NPT 3/4”, G 1/2, and Tri-Clamps at different sizes (eg. 1.5”).  Custom connections are available under request. Having a larger sensing zone, the SRD requires an installation with a clearance of 18 mm from the sensing element. This places the longitudinal axis of the sensor at a minimum distance of 18 mm from the bottom of the tray, requiring the tray to be filled with fluid to a depth of at least 36 mm. Below is an example of the installation of an SRD in a tray using NPT 3/4” as the process connection.

Furthermore, to ensure the highest possible accuracy of density with the SRD at fluid temperatures different than room temperature, follow the installation guidelines explained here: SRD's thermal equilibrium requirements.

Table 2: Recommended accessories for SRD installation in Tray

Effects of vibration, shallow trays, and temperature stability

External vibrations do not affect the operation of the Rheonics SRV and SRD inline sensors. Vibrations will however alter the fluid's behavior. This may add noise to the sensor readings or create ripples that may expose the sensing element to air. In this way, it is important to have enough fluid level and, when reviewing the data, find a baseline in the measurements after which, filters can be applied to the sensor to get clean data.

The effects of vibrations can be avoided by providing sufficient fluid depth. Installations that go below the minimum distances stated in this article are not recommended.

Likewise, temperature is not often controlled for fluids in trays. Since viscosity is temperature dependent, fluctuations in temperature will create fluctuations in measurements. This, however, can easily be corrected by determining the temperature-viscosity relationship and applying the appropriate corrective model. If needed, one can get guidelines from the Rheonics Support Team to set the temperature-compensated viscosity. For more information regarding temperature-compensation models, click here.

Finally, Rheonics recommends the use of adequate accessories. Using the right accessory will eliminate stagnant dead zones leading to better, more accurate results. You can refer to the tables above to find out more about Rheonics' accessories.