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2.3 Recommended orientation

SRD has a sensing tip that is recommended to be aligned with the fluid flow direction to avoid creating recirculation zones around it. Read more on this topic, here.

Figure 4: SRD sensing tip.

2.4 Flow

For Newtonian fluids, the flow rate does not affect the measurements, so SRD should measure the same viscosity and density values in static and moving states of a fluid at the same temperature. 

For non-Newtonian fluids (the vast majority of fluids) the flow rate does matter and viscosity readings may differ between static and moving conditions. Density readings, on the other hand, won't be affected as much as the viscosity reading, and for pure density applications, Newtonian and non-Newtonian fluids can be treated similarly.

For processes with non-constant flow rates, the recommendation is to install the SRD in a section in the pipeline with the most consistent flow rate to have steady reading values.

Flow rate is also relevant to ensure the full submersion of the SRD sensing element into the fluid. For a process with a low flow rate, pipes may not be full of fluid at all points, so SRD should then be placed in a section where the pipe is usually full of fluid (i.e. after a pump). Installing the sensor upwards can also solve the issue but should not be considered for fluids with solids or that can create deposits around the sensing element.

In all cases, the SRD’s sensing element should be submerged in the fluid. It’s best to avoid installations with long standpipes (i.e. using long weldolet or tee), since that may lead to not good fluid transfer resulting in measurements that do not reflect the true state of fluid or worse high noise measurements.

When installing in a standpipe, choose the appropriate insertion length of the sensor by selecting long insertion probes. This allows the sensing element to clear the stagnation zone and be in the fluid that is of interest for measurement, as in the next figure.

Figure 5: Long insertion probes for long standpipes.

2.5 Fluid types

SRD has good performance with the following fluid types and scenarios:

• Static and moving Newtonian fluids
• Moving non-Newtonian fluids: Viscosity can vary at different flow rates, SRD needs to be fully submerged and without stagnation zones.
• Slurries: Typical use case for the SRD. Density in slurries vary with time, as slurry ages, and as it is mixed.
• Fluids with solids of micrometers scale: Solids of the size of rice corn shouldn’t affect measurements.
• Fluids with greater solids: Solids with a bigger size will most likely create spikes in the SRD readings when these hit the sensor. Depending on the percentage of solids in the fluid and after some data analysis, Rheonics may be able to apply some filters to handle these fluids better. However, it is hepful to avoid this kind of solids or install the sensor axially.

3. Process connection installation instructions

3.1 Connection steps

A Tri-Clamp connection requires two ferrules or flanges, a seal and a clamp, as in the next figure.

Figure 6: Tri-Clamp connection components.

The general steps for a Tri-Clamp connection are:

i. Have a welded ferrule in the pipe or tank.

ii. Place the gasket properly into the seat of the ferrule.

iii. Place the sensor Tri-Clamp connection on the gasket and verify it is correctly aligned.

iv. Loosen the clamp so it can fit around the ferrule.

v. Place the clamp, verify ferrules are within the clamp’s groove.

vi. Start tightening the clamp until a leak-proof connection is made.

Be careful not to over-tighten the clamp, this can damage the gasket and ferrules.

3.2 Specific Process Connection installation instructions

• In line: For inline installations consider the sensing area (Figure 3) and a minimum clearance of the sensor tip to the pipe inner wall (12 mm). A perpendicular Tri-Clamp installation of the SRD is not possible for most 1”, 1.5” or 2” pipes (for 2” it depends on the pipe norm). In those cases, the installation is recommended to be parallel or with a flow cell, check accessories FET-15T and IFC-15T-SRD. For bigger lines the sensor can be mounted perpendicular to the flow, Rheonics recommends the WFT-15T ferrule for such cases.
• In tank: Place the sensor at the bottom, wall or lid of the tank as long as the sensing element can be fully submerged in the fluid and dead zones are avoided. The WFT-15T ferrule is recommended for these installations. Usually, it is useful if the sensor is placed at a tank’s height that has always fluid. If there is a hygienic requirement, the SRD-TC can be ordered with a hygienic design as in Figure 1 (optional EHEDG and/or 3-A certification) and should be mounted with a hygienic adapter (e.g. flush welding flange like ISO 1127). 
• Others: Larger pipelines or tanks often need a longer probe (i.e. jacketed tanks or pipes), in those scenarios, the client should use a long insertion probe (FPC sensors) - Order code: SRD-X5.

For special applications contact the Rheonics Team.