What products are involved?
SRV - Inline Viscosity Meter and SRD - Inline Density and Viscosity meter
What is the purpose of this article?
This article provides guidelines on how the Rheonics SRV inline viscometer or SRD density meter can retrofit the Emerson 7829 viscometer in its different installation variants.

1. Introduction

Rheonics SR- sensors measure viscosity, density and temperature inline for process control and monitoring. The SRV measures viscosity while SRD measures density and viscosity, both measure temperature and allow repeatable and reproducible readings with a high accuracy.

The sensor probe is compact, light, hermetically sealed, and factory calibrated. It does not need re-calibration over its operational lifetime, however verification capability is provided in software that comes with the sensor to verify calibration periodically and update if needed in field.

Rheonics sensors are based on a balanced torsional resonator (BTR), this means that the sensing element vibrates torsionally and is connected to the outside world at a node. The patented BTR technology underlying Rheonics sensors have significant advantage over competitors in the market since a balanced torsional resonator allows the SR- sensors to be compact, ligth-weight of reduced dimensions, mass and unaffected by external vibrations. 

2. Retrofit

At times users want to replace an existing viscometer or density meter from their pipelines due to malfunction, lack of spare parts or to try out Rheonics sensors and experience balanced torsional resonator technology. 

In these cases, the user has an existing installation location for the former sensor and wants to install the Rheonics -SR probes in the same location/port. Rheonics -SR sensors favor retrofit installations due to the modular design of the probe. Rheonics offers flush, short and long insertion sensors with all types of process connections while ensuring consistency of performance across all these variants.

Varying the insertion depth and process connection, Rheonics -SR sensors can be ordered to retrofit almost all existing installations. Figure 1 shows the SRV-X4 (Flush Tri-Clamp ), -X2 (Short flanged) and -X5 (Long insertion flanged), all with customizable process connection.

Rheonics favors open standards and these also provide a way for customer to order an alternative sensor when they plan to replace Rheonics ones.

Rheonics SRV inline viscometer variants flush hygienic longFigure 1: Rheonics SRV sensor - versatility in installation options.

Note: Rheonics sensors are suitable for retrofits but care should be taken to comply with minimum installation requirements for the sensing element to ensure reproducible and repeatable readings. These can be reviewed in  installation guideline articles for SRV and SRD.

3. Emerson 7829 Viscometer

This instrument, also known as Viscomaster, is used to measure viscosity, density and temperature inline. Some common installation cases are shown next, highlighting the simplicity to retrofit these units with a Rheonics sensor.

3.1 Flow through chamber for in-line or bypass lines:

Emerson 7829 viscometer is designed with a 1.5” cone seat connection for mounting in a standard chamber as in the next figure.

Notice how Rheonics SR-Sensor doesn’t need an external temperature sensor since it has an in-built PT1000.

Emerson 7829 flow through chamber drawing

Figure 2: Emerson 7829 viscometer installed in a Emerson provided flow through chamber [1].

For this retrofit, if we need to measure viscosity, the order code for Rheonics sensor would be: SRV-X5-A124-B15C (15C is 1.5” Compression fitting e.g. Swagelok). Code  for SRD if density readings are needed is: SRD-X5-A124-B15C.

Rheonics SRV inline viscometer retrofit Emeron flow through chamber

Figure 3: Rheonics SRV retofit in chamber.

3.2 Flange installation:

A well known design of Emerson 7829 Viscometer is with flanges. Rheonics SR- sensors can be ordered with most process connection as it is in the next example for a 2” ANSI flange. User should determine whether the same insertion length (A length in drawing) is needed.

Rheonics offers a more compact and light-weight sensor with repeatable and reproducible readings. Order code in this example would be: SRV-X5-A124-BA20B (SRV-X5-A124-2” ANSI 300lb RF). 

Rheonics SRV inline viscometer retrofit Emeron flow through chamber

Figure 4: Side-by-side: Emerson 7829 and Rheonics SRV flange retrofit.

4. New installations

The Rheonics SR sensors have significant advantages in installation due to its modular design and low or zero wall effects. They ensure repeatable and reproducible readings if two basic installation criteria are met: 

  • sensing element is fully immersed in fluid, and
  • avoid stagnation or dead zones around the probe sensing element. 

Often this means that you can easily remove flow adapters from old sensors and install the SR sensors directly in the line or tank. It also gives you flexibility to install the sensor in tight spots where space is limited. 

Visit installation guideline articles for SRV and SRD for more information. 

Rheonics SRV inline viscometer flexible installation in pipeFigure 5: Rheonics SRV flexible installation.

5. How to order a Rheonics SR- sensor for retrofit?

a. Client should find the connection type needed, specify norm/standard and size in order page. A reference drawing if available should be included.

b. Use online RFQ pages for SRV inline viscometer and SRD viscosity and density meter. 

c. Select connection code. Rheonics offers standard connections as in next table, X2 and X5 codes are good for retrofits since these enables users to select the connection needed.

Sensor order
Connection type
Threaded (NPT or G1/2”)
Standard short probe with custom connection
Flush design probe with custom connection
Long insertion probe with custom connection. Insertion depth (A length) and connection type (B norm, size) also required.

Contact the technical sales team at info@rheonics.com or Technical support team at support@rheonics.com if needed to help you get the correct retrofit.

Pictures, photos, and images used are for illustration purposes and do not constitute any warranty or assertions on the suitability of use and should not be construed as an explicit or implicit recommendation or endorsement. All illustrations are given proper credit from our source of access and by their use here we do not specify or establish any copyright which belongs and stays unaffected with the existing copyright holder of that material.



[1]: Micro Motion 7829 Visconic Viscosity Meter - Emerson

[2]: Rheonics viscometer SRV

[3]: Rheonics density and viscosity meter SRD

[4]: Solutions