Rheonics Support

What is the purpose of this article?
Explain the use and limitations of the SR X5 1-1/4" NPT with a custom Threaded Flange

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

TABLE OF CONTENTS

• The SR X5 Variant
• Using NPT threaded Viscosity and Density meters in flanges

SRV- and SRD-X5 Variant

The X5 is one of the probe variants that Rheonics offers for the Type-SR viscometer (SRV) and density and viscosity meter (SRD). The SRV-X5 and SRD-X5 sensor probes are characterized by their customizable insertion length, which moves the sensing element of the sensor probe deeper into the process or fluid and customizable process connection. These probes are able to work with a wide variety of process connections such as Threaded, NPT, Flanges, Tri-Clamp, etc.

More information on the X5 variant can be found below:

SRV-X5 - Long insertion probe - SRV-X5: Long insertion probe 

SRD-X5 - Long insertion probe - SRD-X5: Long insertion probe 

Using NPT threaded Viscosity and Density meters in flanges

Flanges are process connections commonly used in industry, These are generally used in applications that require high-pressure conditions and need matching flange faces alongside bolts and a seal for a full assembly. Flange designs are standardized, below are some of the most common norms for flanges:

• ANSI Flanges: North American standard for flanges. ANSI/ASME B16.5 standard defines flanges by pipe size, pressure rating (lbf) and type, raised face (RF), flat face (FF), or ring-type joint (RTJ).

• DIN Flanges: German standard for flanges. DIN 2527 standard defines the sizes available in DN (Nominal Diameter) and PN (Nominal Pressure) while flange type can be flat or raised face.

• JIS Flanges: Japanese Industrial Standards. JIS B2220 standard defines nominal sizes from 10 A to 1500 A and nominal pressure from 5K to 63K.

• BS/EN Flanges: British Standard. BS/EN 1092 standard is used to categorize flanges by dimensions (DN) and nominal pressure (PN).

NPT on the other hand is a thread norm defined under ANSI/ASME standard B1. 20.1 which describes a thread style that is designed to fit by compression thanks to its tapered thread. This style of process connection generally requires a bonding agent (Teflon tape or adhesive for example) and is commonly used in piping across America. 

Figure 2: SRV-HD-X5 and SRD-HD-X5 with 1.25" NPT process connection

In the case of the Type-SR sensor probes, the SR X5 can be equipped with a 1.25” NPT process connection. This probe variant then becomes a modular solution that can be used with custom threaded flanges bigger than 1.5” that fit this thread type. This added to the variable insertion length of the probe, opens multiple possibilities for customers, including:

• Easily replacing the sensor probe

• Fitting one sensor to multiple flange types and sizes

• Convenience in terms of inventory and spare parts management

• Having flanges sourced/manufactured locally

• Reduces size, weight, and cost compared to a probe with a flange welded

Figure 3: SRV-X5-NPT fitted to an ANSI Flange for a tank wall installation

Below are some examples of how the Type-SR X5 1-1/4" NPT Variant is installed in various applications.

Table 1: Installation drawings for the Type-SR X5 1-1/4" NPT Variants

Note: When using the SR X5 1-1/4" NPT, the pressure rating is limited by the sensor probe and should not exceed 100 bar. This should be taken into account when planning installations under high pressure.

Customer Flange Preparation

Customers can order this probe variant and prepare a matching flange in-house to save on costs and time. The probe threads into any flange that:

1. Can have a female 1.25” NPT threaded hole machined. (Minimum sizes for ANSI/ASME B16.5 flanges are 1.5” for both pressure classes 150 and 300)

2. Has a matching port with an ID of at least 32 mm

Figure 4: Threaded flange and mating flange/port requirements for SRV-X5-NPT

Any flange that fits these conditions can be used with this sensor probe variant, meaning flanges of multiple sizes and classes can be fitted to the same sensor variant. This is advantageous when looking to standardize sensor variants across a process line, making drop-in replacements an alternative.

Currently, threaded flanges are offered by online manufacturers, which makes sourcing them easier. Usually, suppliers provide the most common or commercially available flanges. Below is a table showing the alternatives offered by McMaster Carr, a popular source of hardware and tools:

Table 2: McMaster Carr - 1.25" NPT Threaded Flanges in Stainless Steel

Low-Pressure Stainless Steel Threaded Pipe Flanges

High-Pressure Stainless Steel Threaded Pipe Flanges

Finally, Rheonics can prepare and send a matching flange if desired by the customer.