What products are involved?
SRV - Inline Viscosity Meter
What is the purpose of this article?
To give an overview of the Reactor Probe (-RP) version of the SRV sensor and installation information.
1. Overview
The Rheonics Reactor Probe (RP) design for the viscometer SRV is a long insertion probe with a body diameter of 19mm, configurable by total “L” length and flexible (adjustable) process connection, with PTFE-PEEK or Stainless Steel 316L compression fittings.
The Rheonics SRV is used inline to monitor the real-time viscosity and temperature values of a fluid. See more about the SRV and other variants here.
The SRV-RP design is well suited for installations in bioreactor tanks and glass reactors using a long insertion probe with compression fittings with process connection as 1” NPT, 3.4” NPT, and others.
PTFE-PEEK fittings allows the user to vary the insertion length of the sensor (distance from fitting to sensor tip) since the fitting can be moved along the shaft of the probe. Stainless Steel compression fittings are generally fixed in a position.
The SRV-RP is offered in 4 different total lengths: 150, 250, 350 and 450mm. Client can also define the compression fitting required that will be placed at some point along the shaft once received.
Figure 1: SRV-RP250-B34NP - Reactor Probe Viscometer 3/4" NPT PTFE Compression Fitting
Figure 2: SRV-RP Reactor Probe dimensions in mm (inch)
| Specifications | |
| Sensor compatibility | |
Order code | SRV-RPyyy-Bzzz |
Total length L - yyy | 150, 250, 350 and 450 mm |
Connection type B - zzz | Customizable (min. OD 22mm) |
Drawings | SR-RP Configuration Drawing |
SRV-RP CAD files | ||
Sensor Variant | Drawing | CAD File |
SRV-RP150 | ||
SRV-RP250 | ||
SRV-RP350 | ||
SRV-RP450 | ||
With the reactor probe there are many installation advantages. Some installation scenarios of this sensor variant are:
- Installation in reactors, in particular bioreactors
- Installations with variable insertion length
- Installation in small pipe sizes (e.g. 1”, 1.25” ID pipes)
- Installation in pipe sizes bigger than 1.5” with reduced (compared to -X5 sensors) cross section reduction inside the pipe due to probe.
Figure 3: SRV-X7 Reactor Probe comparison with SRV-X5
2. Installation principles
The Rheonics SRV-RP has the following installation criterias that should be met to ensure accurate, repeatable and reproducible viscosity readings.
Figure 4: SRV-X7 Reactor Probe Sensing element
3. Fitting options
A compression fitting is a mechanical device useful to create a sealed connection between two pieces (e.g. pipes) without welding or heating. It is based on compression forces between its inner parts, which are a Compression Nut, Back Ferrule, Front Ferrule and Fitting Body. The later is connected to the process by a custom connection.
Figure 6: Compression Fitting parts
Rheonics sensors such as the SRV-RP can use a compression fitting to offer a process connection for installation, without having the flange or thread welded on the sensor body. Next Figure shows how the back or rear ferrule is compressed against the sensor body once the nut is threaded in the fitting or connector body. Compression deforms the back ferrule and depending on the material, the ferrule will go back to its original state once decompressed, or stay deformed and fixed in its position.
Rheonics sensors such as the SRV-RP can use a compression fitting to offer a process connection for installation, without having the flange or thread welded on the sensor body. Next Figure shows how the back or rear ferrule is compressed against the sensor body once the nut is threaded in the fitting or connector body. Compression deforms the back ferrule and depending on the material, the ferrule will go back to its original state once decompressed, or stay deformed and fixed in its position.
Figure 7: Rheonics RP Compression Fitting Cross Section View
3.1 PTFE-PEEK Compression Fittings
As mentioned in section 1, PTFE compression fittings can be moved along the sensor probe shaft and be compressed at different points each time it is installed.
Fitting is mainly made of PTFE and includes a PEEK olive back ferrule for a secure grip. These compression fittings have excellent chemical and temperature resistance and reduce contamination and cleaning required.
See how to install the PTFE-PEEK compression fitting here
Figure 8: PTFE-PEEF Compression Fittings. Source: Avantor
3.2 Stainless Steel Compression Fitting
These fittings have all inner parts (connector, nut and ferrules - back and front) made of Stainless Steel SS316L. This offer a higher pressure rating. The ferrules get deformed when nut is tightened first time, creating a mechanical bond with the probe shaft. This has the advantage of defining a fixed position for thread engagement but also means that user can’t vary the compression point after first installation.
See how to install the Stainless steel compression fitting here
Figure 9: Stainless Steel Compression Fitting. Source: Swagelok
4. Configuration examples
Some examples of possible configurations for the SRV-RP sensor are shown below:
3/4” NPT Thread: SRV Reactor probe with 3/4”-14 NPT compression fitting in PTFE or SS316L material. Rheonics offers this connection welded in its standard short sensor SRV-X1. The advantage the -RP Type sensor offers is the longer insertion of the probe as shown in next two figures for a 150 and 250 L variant.
Figure 10: SRV-RP150-B34N
Figure 11: SRV-RP150-B34N
SRV-RP L: 250 mm B: 3/4” NPT | |
Part | Order Code |
SRV-RP Reactor Probe Viscometer | SRV-RP250-B34N |
1” NPT: Compression fittings for the SRV-RP are also available with 1” NPT connection for Stainless Steel and PTFE-PEEK variants.
Figure 12: SRV-RP250-B11N
SRV-RP L: 250 mm B: 1” NPT | |
Part | Order Code |
SRV-RP Reactor Probe Viscometer | SRV-RP250-B11N |
5. How to order the Rheonics Reactor Probe?
Rheonics SRV-RP follows next code form.
How to Order Rheonics long insertion viscometer and density meter | |||
 | |||
1 | Rheonics SR-Type sensor SRV: Inline Viscometer SRD: Inline Density and Viscosity meter | 3 | Process Connection "B" Compression fittings defined by client. Common variants are: 3/4” NPT, 1” NPT in Stainless Steel (-S) and PTFE-PEEK (-P). Ask Rheonics Sales Team for availability of other connections.
|
2 | Reactor Probe RP- Length Length from sensor probe back end to tip. Rheonics offers 4 variants:
| ||
The appropriate RFQ page for SRV viscometer should be used to configure other options of the sensor, like viscosity range, calibration accuracy, pressure rating, etc. | |||
References
[1]: Compression screw fittings
[2]: Swagelok