Pressure Sensor Process Connection

Pressure Sensor Process Connection

by | Aug 11, 2021

The Guide abut Pressure Sensor Process Connection
THE GUIDE IN 2021
Contents
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Introduction

An accurate and reliable process connection ensures a seamless interface between the pressure sensor and the equipment being monitored, enabling precise readings and helping to prevent leaks or other issues that could compromise the system’s performance.

Each process connection method offers unique benefits depending on the specific requirements. In this article, I will guide you through the four main types of process connection methods—threaded connections, flanged connections, welded connections, and submersible connections—and highlight their key features:

Threaded Connections

Threaded connections are a widely used and cost-effective solution for joining pressure sensors to equipment. They offer flexibility in installation and can easily be adjusted or removed in case of maintenance. Some common thread types include NPT, BSP, Metric and PT Threads. Tightening torque should be carefully considered when installing threaded connections, as it directly impacts the effectiveness of the seal.

The most widely used thread types for pressure sensor connections include

  • National Pipe Thread (NPT),
  • British Standard Pipe (BSP),
  • Metric threads. Standards:
  • PT (Pipe Taper) threads,
1/2"BSP MALE1/2"G EN837 DIN16288
1_2'BSP MALEEN83701 G_2B G1_2A DIN 16288 FORM B
1/2"NPT MALE1/4"NPT MALE
1_2'NPT MALE1_4'NPT MALE

For more details about threads connection, you can check

Flanged Connections

Flanged connections provide a reliable and robust solution, particularly for high-pressure applications. Consisting of two flanges bolted together, these connections create a strong, pressure-tight seal, while still allowing easy disassembly for maintenance. ANSI, DIN, and JIS are popular flange standards, and proper selection of gasket type and material—depending on operating conditions—plays a crucial role in ensuring a secure connection.

Transmitter Flange Pressure Class under ASME Standard_1

Flanged process connections bring numerous advantages to the table, making them popular choices for various industries and applications. Their notable benefits include:

  • Robust sealing: Flanges provide a strong, pressure-tight seal, suitable for high-pressure applications.
  • Easy maintenance: The bolted design allows easy disassembly for maintenance or replacement purposes.
  • Compatibility: Flanges are compatible with different materials and can be used for various pipe sizes and pressure ratings.

Regarding types of flanges, several common options are available based on industry needs and specific requirements. Some popular flange types include:

  • Welding Neck: Known for their durability and high-pressure resistance, these flanges are often used in extreme conditions.
  • Slip-On: Economical and easy to install, slip-on flanges are versatile and suitable for low-pressure applications.
  • Socket Weld: These flanges offer a secure connection for smaller pipes in high-pressure applications.
  • Lap Joint: Lap joint flanges facilitate easy disassembly for systems requiring regular maintenancePressure Transmitter Flange Table-eastsensor2.
  • Threaded: These flanges enable connection to threaded pipes without welding, making them suitable for low-pressure applications and instances where welding is unfeasible.

When it comes to flanged process connection installation, please also keep the following tips in mind:

  • Ensure proper alignment and leveling of the flange faces to achieve a uniform seal.
  • Select the appropriate gasket type and material based on the application, pressure, and temperature requirements.
  • Follow the recommended bolt-tightening procedure and torque values to avoid over-tightening or under-tightening, which can compromise the seal.
  • Choosing the right flange type for your application requires careful consideration of factors such as pressure and temperature ratings, pipe size, material compatibility, and maintenance requirements. Assess the specific needs of your application and compare them to the features and limitations of each flange type to determine the best option.

Click to check more details about Flange

Welded connections

Welded connections are an excellent choice for high-pressure and high-temperature applications, wherein durability and reliability are of paramount importance. By permanently fusing the pressure sensor to the equipment, we create a leak-proof bond that enhances system integrity. Various welding techniques, such as Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG), are used based on the materials and work environment. However, the permanence of welded connections may make maintenance or sensor replacement more challenging than in other connection types.

Check More: ESS322 All Welded Pressure Sensor

Welded Pressure Sensor

Welded process connections provide several benefits that make them suitable for high-pressure and demanding applications:

  • Superior strength: Welded connections form a strong, permanent bond between the pressure sensor and the equipment or piping.
  • Leak-proof: By eliminating potential leak points associated with threaded or flanged connections, welded connections provide an airtight seal.
  • High-pressure and high-temperature compatibility: Welded connections are designed to withstand extreme pressure and temperature conditions.

Various welding techniques can be employed for welded process connections, depending on the materials and application requirements:

  • Tungsten Inert Gas (TIG) Welding: A precise welding technique suitable for thin materials and exotic metals, TIG welding offers excellent control and a clean finish.
  • Metal Inert Gas (MIG) Welding: MIG welding is a versatile method, ideal for a wide range of materials and thicknesses, providing increased productivity and lower distortion levels.
  • Shielded Metal Arc Welding (SMAW): SMAW is a common technique for field welding and joining thick and heavy materials, offering portability and strong welds.

When dealing with high-pressure applications, consider the following factors for welded process connections:

  • Material compatibility: Select welding materials that are compatible with the pressure sensor and the equipment or piping to avoid potential failure points due to material incompatibility.
  • Preparatory work: Proper cleaning and preparation of the surfaces to be welded are vital for achieving a sturdy connection and minimizing the risk of contamination or defects.
  • Heat treatment: In certain cases, post-weld heat treatment may be necessary to relieve stress and improve the connection’s structural integrity.

To ensure the reliability of welded connections, adopt these best practices:

  • Qualification of welders: Employ qualified welders with the necessary training and certifications to guarantee the quality of the welded connection.
  • Visual inspection: Conduct regular visual inspections of the welded connections to identify any surface defects or irregularities.
  • Non-destructive testing (NDT): Techniques such as ultrasonic testing, radiographic testing, or dye penetrant testing can be used to identify subsurface defects in welded connections that may not be visible to the naked eye.

Submersible connections

Submersible connections are designed to perform efficiently in underwater or fluid-immersed environments. These connections are watertight, corrosion-resistant, and capable of withstanding higher-pressure levels. A robust sealing system, typically comprising O-rings or hermetic seals, is essential for maintaining the reliability of submersible connections. Periodic inspection for signs of wear and corrosion is crucial to ensure optimal performance.

Submersible process connections offer several advantages that make them ideal for underwater or fluid-immersed environments:

  • Watertight seals: Engineered to function efficiently in submerged conditions, submersible connections provide reliable watertight seals.
  • Corrosion resistance: Materials used for submersible process connections are often corrosion-resistant, ensuring longevity and functionality in harsh circumstances.
  • External pressure compensation: Submersible pressure sensors can account for external pressure changes, offering accurate readings in submerged applications.

Submersible pressure sensors are employed in a variety of applications:

  • Water and wastewater treatment plants: Monitoring water levels, flow rates, and pressure in submerged pipes and tanks.
  • Oceanographic research and marine industries: Supporting underwater exploration, subsea equipment, and environmental studies.
  • Flood monitoring systems: Gauging water levels and providing early warning signals during floods.

To ensure optimal installation and maintenance of submersible process connections, consider the following tips:

  • Cable selection: Choose a cable that is specifically designed for underwater use, considering factors such as tensile strength, corrosion resistance, and chemical compatibility.
  • Cable entry seal: Ensure that the cable entry point into the pressure sensor housing is watertight to prevent moisture ingress.
  • Use adequate cable supports: Properly support and secure cables to prevent excessive strain and potential damage to the connection.
  • Regular inspection: Periodically inspect the submerged connections for any signs of wear, damage, or corrosion and promptly rectify any issues to ensure continued reliability.

Challenges encountered in underwater pressure sensor connections include:

  • Material selection: Identifying materials that can withstand harsh underwater conditions, providing corrosion resistance and ensuring long-lasting performance.
  • Proper sealing: Ensuring the connections remain watertight and do not compromise the overall system integrity.
  • Signal interference: Overcoming potential signal interference or attenuation due to the effects of water or other environmental factors.

Temperature Effects on Process Connections

Let’s explore the effects of temperature fluctuations on process connections, material selection for temperature extremes, temperature compensation in pressure sensors, and avoiding thermal cycling issues in process connections.

Impact of temperature fluctuations on process connections: Temperature changes can affect process connections in various ways, including:

Thermal expansion and contraction:

Materials expand and contract due to temperature fluctuations, potentially leading to loose connections or leaks.

Seal degradation: Temperature changes can affect the performance and longevity of seals and gaskets in the connections.

Material limitations: Some materials may lose mechanical strength or undergo structural changes when exposed to extreme temperatures, compromising the connection’s integrity.

Material selection for temperature extremes:

Selecting materials capable of withstanding temperature extremes is crucial for maintaining the reliability of process connections. Common materials include:

  • Stainless steel: Offers excellent resistance to a wide range of temperatures and maintains its mechanical properties.
  • High-temperature alloys (Inconel, Hastelloy): These alloys are suitable for applications with extreme temperatures and offer excellent resistance to oxidation and corrosion.
  • PTFE (Teflon): For seals and gaskets, PTFE exhibits excellent resistance to temperature extremes and chemical compatibility.

Wrap up

In today’s guide, we discuss four different ways to connect pressure sensors to equipment: threaded connections, flanged connections, welded connections, and submersible connections. Each method has its own benefits and requires specific installation and maintenance procedures. Temperature changes can also affect these connections, and the article suggests using special materials like alloys and PTFE for seals and gaskets to handle extreme temperatures.

Threaded connections involve screwing the sensor into the equipment, while flanged connections use bolts to attach the sensor to a flange on the equipment. Welded connections involve fusing the sensor to the equipment, and submersible connections are designed for use in liquids and require a waterproof seal.

The article provides tips on properly installing and maintaining each type of connection, including using appropriate torque values and checking for leaks. It also emphasizes the importance of selecting the suitable materials for the temperature range of the equipment, as well as regularly inspecting and replacing worn or damaged seals and gaskets. Overall, this guide provides useful information for anyone looking to connect pressure sensors to their equipment safely and effectively.

How to Choose the Correct Pressure Transmitter Manifold

How to Choose the Correct Pressure Transmitter Manifold

by | Sep 1, 2018

Contents
2
3

Introduction

Pressure Transmitter Manifold valves consolidate multiple single valves into a single valve block. This method allows the user to use these multiple valves in a single block to perform multiple functions and tasks without removing the Differential Pressure Transmitter (DP) from its installed position. The single block minimizes the number of connections and potential leak points which makes for a more secure process connection.

A valve manifold is often used with a DP transmitter so that it can isolate and equalize pressure exerted on the transmitter whenever any process is taking place. This valve is manual, but it is useful for calibration and maintenance purposes. Find the details about DP Transmitter Application. And the Basics of DP Transmitter.

The 3 Valve Manifold

This device ascertains that the capsule does not exceed beyond its designated range and does not isolate the pressure transmitter manifold from the entire process. As the name implies, the 3-valve manifold actually comprises of three valves— a high pressure block valve, a lower pressure block valve and an equalizing valve.

The block valves work together to isolate the instruments. The equalizing valve, placed in between the low and high transmitter process connections, ensures equal pressure on both sides.

Study the image below depicting a 3 valve manifold shown within the dotted box. Often, an additional valve, referred to as the bleed valve, emits the trapped pressure into the atmosphere.

An image depicting the 3 valve manifold

Though the image above actually shows four valves, a standard 3 valve manifold only features two block valves and one equalizing valves as mentioned earlier; the block valve is often not included.

Also, this image depicts the three valves as completely separate devices that have been connected with each other and to the transmitter through tubing.

In essence, this kind of valve is fabricated as a monolithic device, featuring all three valves that are casted together into a single metallic block, which is attached to the pressure transmitter with O-ring seals, which often have a flanged face.

Bleed valves are, however, connected separately. They are often threaded into the transmitter’s chambers.

Refer to the image given below, which shows another version of a 3 valve manifold, connected to a differential pressure transmitter. Note the upper port on the diaphragm capsule; a bleed valve can be inserted into the port externally.

Generally, the two block valves are open so that fluid pressure can reach the differential transmitter. However, the equalizing valve is closed tightly to prevent the fluid from passing between the low and high pressure sides.

If the transmitter has to undergo maintenance, then it must be isolated first. This is done by shutting off the block vales and releasing the equalizing valve.

Valving a Differential Pressure Transmitter with 3 Valves Manifold into Service

A pressure transmitter manifold can be valved by performing the steps outlined below.

  1. Check and ensure that every valve is closed.
  2. Open the equalizing valves so as to ascertain that uniform pressure is applied on both sides of the transmitter manifold. This uniform pressure is formally referred to as zero differential pressure.
  3. Slowly turn on the higher pressure block valve. Inspect both sides of the transmitter and make sure there are no leakages.
  4. Now shut the equalizing valve such that pressure is locked on either side of the transmitter.
  5. Release the low pressure block valve to exert pressure on the low pressure side of the transmitter. Let the valve remain open until differential pressure has been established.
  6. The pressure transmitter manifold is now in operation.

In some instances, a bleed valve may be required, allowing trapped air to be released into the environment through the capsule housing.

Removing the Pressure Transmitter Manifold from Service

Perform the above steps in reverse order to remove the differential pressure transmitter from service. First shut the low pressure block valve. Now turn on the equalizing valve and then shut the high pressure valve.

The pressure transmitter manifold is inoperable now. Ensure that valves are opened and closed in the exact sequence presented here so as to ascertain two main things—that a high differential pressure isn’t reached when isolating the pressure transmitter manifold and that the inside fluid pressure is minimum before the transmitter is vented.

Even after being removed from service, the pressure will still be exerted on the capsule, which should then be decreased through bleeding.  Thus, the last step is to open the bleed valve, which releases the trapped pressure inside the transmitter manifold.

The illustrations below show the final valve positions when a transmitter is in service and when it has been removed.

Operational and non operational states of a pressure transmitter manifold

5-Way Valve Manifold

In this type of pressure transmitter manifold, the bleed valve is built-in. Instead of venting out the pressure at the transmitter itself, this valve allows the trapped pressure to be passed through a tube and released at a remote location.

If the 5-way valve manifold is under normal operation, then both the low pressure and the high pressure valves are opened, whereas the other two valves are closed. Please ensure that the equalizing valve is never opened if both blocking valves are released.

Such a state can damage the pressure transmitter and manifold or even expose personnel to hazards if the fluid is too hot or of radioactive nature. Hence, a 5 valve pressure transmitter manifold is often to prevent situations of this sort.

pressure transmitter manifold- DP-transmitter-Eastsensor Technology

The block diagram of a 5 valve pressure transmitter is shown below.

5 Valve Manifold

Valving a Differential Pressure Transmitter with 5 Valves Manifold into Service

  1. Ensure that all five valves are closed.
  2. Open the equalizing valve first so that zero differential pressure is applied to both ends of the transmitter.
  3. Now turn on the high pressure valve slowly, simultaneously checking for potential leakages on both sides of the transmitter.
  4. Turn off the equalizing valve so as to lock pressure.
  5. Turn on the low pressure valve; this should establish a differential pressure.
  6. The transmitter is now said to be in service.

Removing a 5 Valve Manifold Transmitter from Service

Close both the low and the high pressure valves. Release the equalizing valve and then the bleed valve to emit process pressure into the environment.

The transmitter can now be said to be out of service. As in the case of a 3 valve manifold transmitter, the capsule will still be under pressure, which can be removed through bleeding.

The valve positions for both operational and nonoperational states are shown below.

5 Valve Manifold Transmitter under operation and removed from service

Please bear in mind never to release the equalizing valve if both block valves are opened simultaneously.

If care is not exhibited, process fluid can reach the low and high pressure transmitter sides by passing through the equalizing valve. This can damage the transmitter and may even lead to human injuries.

If the tubes connecting the process and manifold are filled up with a fluid like glycerin or steamed water, it will be lost. Full fluids may be used for directing process water away from the impulse tubes.

2-Way Valve Manifolds

The 2-way valve pressure transmitter manifold works best for gauge pressure applications and it has single block-and-bleed configurations. The low pressure port is released into the atmosphere, whereas the high pressure port is connected to the device.

2 Valve DP Transmitter

For removing the transmitter out of service, shut the blocking valve and release the bleed valve. This will vent out process pressure into the atmosphere.

The following image depicts eight pressure transmitters connected to each other. Seven of these feature a single capsule containing both the block and bleed valves, whereas the eighth transmitter (second transmitter from the left, located in the bottom row) comprises of a 5 valve manifold transmitter.

Study the figure carefully and note that a single bleed valve is attached to all the upper ports. Only the 5-valve transmitter is equipped with two bleed valves because it is the only device that can establish differential pressure. The rest of the transmitters are gauge pressure units, and hence, feature only a single bleed valve.

Operational Advice

When opening valves, back them off at least one quarter of a turn. This prevents seizing under normal operations and allows personnel to easily figure out the states of the valves.

A closed valve doesn’t turn easily because it is completely tightened in place, whereas an open valve can easily turn in either direction. However, closed valves shouldn’t be “backed off” because they must be secured tightly into place to remain in the shut-off position.

Pressure Transmitter Flange Table

Pressure Transmitter Flange Table

by | Aug 8, 2018

Pressure Transmitter Flange is commonly used to connect pressure transmitter into pipework making it easier for removal and maintenance. There are many common Flange Standards and Pressure Transmitter Flange within the same standard can either be flat (commonly cast iron, ductile iron) or raised face (commonly cast steel and stainless steel).

Click to Find Out details of Diaphragm Seals for EST4300 Smart Pressure/Differential Transmitter

Below is a reference table for critical flange dimensions to help identify what standard you have.

Pressure Transmitter Flange Table-eastsensor2

FLANGE DIMENSIONS TABLE SIZE (DN) 15 (1/2″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN203 1/2″ / 89mm2 3/8″ / 60mm41/2″5/8″ / 16mm
ANSI 600PN1003 3/4″ / 95mm2 5/8″ / 67mm41/2″5/8″ / 16mm
ANSI 900PN1504 3/4″ / 121mm3 1/4″ / 83mm43/4″7/8″ / 22mm
ANSI 1500PN2504 3/4″ / 121mm3 1/4″ / 83mm43/4″7/8″ / 22mm
ANSI 2500PN4205 1/4″ / 1333 1/2″ / 89mm43/4″7/8″ / 22mm
FLANGE DIMENSIONS TABLE SIZE (DN) 20 (3/4″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN203 7/8″ / 98mm2 3/4″ / 70mm41/2″5/8″ / 16mm
ANSI 300PN504 5/8″ / 117mm3 1/4″ / 83mm45/8″3/4″ / 19mm
ANSI 600PN1004 5/8″ / 117mm3 1/4″ / 83mm45/8″3/4″ / 19mm
ANSI 900PN1505 1/8″ / 130mm3 1/2″ / 89mm43/4″7/8″ / 22mm
ANSI 1500PN2505 1/8″ / 130mm3 1/2″ / 89mm43/4″7/8″ / 22mm
FLANGE DIMENSIONS TABLE SIZE (DN) 25 (1″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN204 1/4″ / 108mm3 1/8″ / 79mm41/2″5/8″ / 16mm
ANSI 300PN504 7/8″ / 124mm3 1/2″ / 89mm45/8″3/4″ / 19mm
ANSI 600PN1004 7/8″ / 124mm3 1/2″ / 89mm45/8″3/4″ / 19mm
ANSI 900PN1505 7/8″ / 149mm4″ / 102mm47/8″1″ / 25mm
ANSI 1500PN2505 7/8″ / 149mm4″ / 102mm47/8″1″ / 25mm

FLANGE DIMENSIONS TABLE SIZE (DN) 32 (1 1/4″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN204 5/8″ / 117mm3 1/2″ / 89mm41/2″5/8″ / 16mm
ANSI 300PN505 1/4″ / 133mm3 7/8″ / 98mm45/8″3/4″ / 19mm
ANSI 600PN1005 1/4″ / 133mm3 7/8″ / 98mm45/8″3/4″ / 19mm
ANSI 900PN1506 1/4″ / 159mm4 3/8″ / 111mm47/8″1″ / 25mm
ANSI 1500PN2506 1/4″ / 159mm4 3/8″ / 111mm47/8″1″ / 25mm
FLANGE DIMENSIONS TABLE SIZE (DN) 40 (1 1/2″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN205″ / 127mm3 7/8″ / 98mm41/2″5/8″ / 16mm
ANSI 300PN506 1/8″ / 156mm4 1/2″ / 114mm43/4″7/8″ / 22mm
ANSI 600PN1006 1/8″ / 156mm4 1/2″ / 114mm43/4″7/8″ / 22mm
ANSI 900PN1507″ / 178mm4 7/8″ / 124mm41″1 1/8″ / 29mm
ANSI 1500PN2507″ / 178mm4 7/8″ / 124mm41″1 1/8″ / 29mm
FLANGE DIMENSIONS TABLE SIZE (DN) 50 (2″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN206″ / 152mm4 3/4″ / 121mm45/8″3/4″ / 19mm
ANSI 300PN506 1/2″ / 165mm5″ / 127mm85/8″3/4″ / 19mm
ANSI 600PN1006 1/2″ / 165mm5″ / 127mm85/8″3/4″ / 19mm
ANSI 900PN1508 1/2″ / 216mm6 1/2″ / 165mm87/8″1″ / 25mm
ANSI 1500PN2508 1/2″ / 216mm6 1/2″ / 165mm87/8″1″ / 25mm
FLANGE DIMENSIONS TABLE SIZE (DN) 65 (2 1/2″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN207″ / 178mm5 1/2″ / 140mm45/8″3/4″ / 19mm
ANSI 300PN507 1/2″ / 191mm5 7/8″ / 149mm83/4″7/8″ / 22mm
ANSI 600PN1007 1/2″ / 191mm5 7/8″ / 149mm83/4″7/8″ / 22mm
ANSI 900PN1509 5/8″ / 244mm7 1/2″ / 191mm81″1 1/8″ / 29mm
ANSI 1500PN2509 5/8″ / 244mm7 1/2″ / 191mm81″1 1/8″ / 29mm
FLANGE DIMENSIONS TABLE SIZE (DN) 80 (3″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN207 1/2″ / 191mm6″ / 152mm45/8″3/4″ / 19mm
ANSI 300PN508 1/4″ / 210mm6 5/8″ / 168mm83/4″7/8″ / 22mm
ANSI 600PN1008 1/4″ / 210mm6 5/8″ / 168mm83/4″7/8″ / 22mm
ANSI 900PN1509 1/2″ / 241mm7 1/2″ / 191mm87/8″1″ / 25mm
ANSI 1500PN25010 1/2″ / 267mm8″ / 203mm81 1/8″1 1/4″ / 32mm
FLANGE DIMENSIONS TABLE SIZE (DN) 100 (4″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN209″ / 229mm7 1/2″ / 191mm85/8″3/4″ / 19mm
ANSI 300PN5010″ / 254mm7 7/8″ / 200mm83/4″7/8″ / 22mm
ANSI 600PN10010 3/4″ / 273mm8 1/2″ / 216mm87/8″1″ / 25mm
ANSI 900PN15011 1/2″ / 292mm9 1/4″ / 235mm81 1/8″1 1/4″ / 32mm
ANSI 1500PN250112 1/4″ / 311mm9 1/2″ / 241mm81 1/4″1 3/8″ / 35mm
FLANGE DIMENSIONS TABLE SIZE (DN) 125 (5″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2010″ / 254mm8 1/2″ / 216mm83/4″7/8″ / 22mm
ANSI 300PN5011″ / 279mm9 1/4″ / 235mm83/4″7/8″ / 22mm
ANSI 600PN10013″ / 330mm10 1/2″ / 267mm81″1 1/8″ / 29mm
ANSI 900PN15013 3/4″ / 349mm11″ / 279mm81 1/4″1 3/8″ / 35mm
ANSI 1500PN25014 3/4″ / 375mm11 1/2″ / 292mm81 1/2″1 5/8″ / 41mm
FLANGE DIMENSIONS TABLE SIZE (DN) 150 (6″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2011″ / 279mm9 1/2″ / 241mm83/4″7/8″ / 22mm
ANSI 300PN5012 1/2″ / 318mm10 5/8″ / 270mm123/4″7/8″ / 22mm
ANSI 600PN10014″ / 356mm11 1/2″ / 292mm121″1 1/8″ / 29mm
ANSI 900PN15015″ / 381mm12 1/2″ / 318mm121 1/8″1 1/4″ / 32mm
ANSI 1500PN25015 1/2″ / 394mm12 1/2″ / 318mm121 3/8″1 1/2″ / 38mm
FLANGE DIMENSIONS TABLE SIZE (DN) 200 (8″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2013 1/2″ / 343mm11 3/4″ / 298mm83/4″7/8″ / 22mm
ANSI 300PN5015″ / 381mm13″ / 330mm127/8″1″ / 25mm
ANSI 600PN10016 1/2″ / 419mm13 3/4″ / 349mm121 1/8″1 1/4″ / 32mm
ANSI 900PN15018 1/2″ / 470mm15 1/2″ / 394mm121 3/8″1 1/2″ / 38mm
ANSI 1500PN25019″ / 483mm15 1/2″ / 394mm121 5/8″1 3/4″ / 44mm
FLANGE DIMENSIONS TABLE SIZE (DN) 250 (10″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2016″ / 406mm14 1/4″ / 362mm127/8″1″ / 25mm
ANSI 300PN5017 1/2″ / 445mm15 1/4″ / 387mm161″1 1/8″ / 29mm
ANSI 600PN10020″ / 508mm17″ / 432mm161 1/4″1 3/8″ / 35mm
ANSI 900PN15021 1/2″ / 546mm18 1/2″ / 470mm161 3/8″1 1/2″ / 38mm
ANSI 1500PN25023″ / 584mm19″ / 483mm121 7/8″2″ / 51mm
FLANGE DIMENSIONS TABLE SIZE (DN) 300 (12″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2019″ / 483mm17″ / 432mm127/8″1″ / 25mm
ANSI 300PN5020 1/2″ / 521mm17 3/4″ / 451mm161 1/8″1 1/4″ / 32mm
ANSI 600PN10022″ / 559mm19 1/4″ / 489mm201 1/4″1 3/8″ / 35mm
ANSI 900PN15024″ / 610mm21″ / 533mm201 3/8″1 1/2″ / 38mm
ANSI 1500PN25026 1/2″ / 673mm22 1/2″ / 572mm162″2 1/8″ / 54mm
FLANGE DIMENSIONS TABLE SIZE (DN) 350 (14″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2021″ / 533mm18 3/4″ / 476mm121″1 1/8″ / 29mm
ANSI 300PN5023″ / 584mm20 1/4″ / 514mm201 1/8″1 1/4″ / 32mm
ANSI 600PN10023 3/4″ / 603mm20 3/4″ / 527mm201 3/8″1 1/2″ / 38mm
ANSI 900PN15025 1/4″ / 641mm22″ / 559mm201 1/2″1 5/8″ / 41mm
ANSI 1500PN25029 1/2″ / 749mm25″ / 635mm162 1/4″2 3/8″ / 60mm
FLANGE DIMENSIONS TABLE SIZE (DN) 400 (16″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2023 1/2″ / 597mm21 1/4″ / 540mm161″1 1/8″ / 29mm
ANSI 300PN5025 1/2″ / 648mm22 1/2″ / 572mm201 1/4″1 3/8″ / 35mm
ANSI 600PN10027 1/2″ / 699mm23 3/4″ / 603mm201 1/2″1 5/8″ / 41mm
ANSI 900PN15027 1/2″ / 699mm23 3/4″ / 603mm201 1/2″1 5/8″ / 41mm
ANSI 1500PN25032 1/2″ / 826mm27 3/4″ / 705mm162 1/2″2 5/8″ / 67mm
FLANGE DIMENSIONS TABLE SIZE (DN) 450 (18″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2025″ / 635mm22 3/4″ / 578mm161 1/8″1 1/4″ / 32mm
ANSI 300PN5028″ / 711mm24 3/4″ / 629mm241 1/4″1 3/8″ / 35mm
ANSI 600PN10029 1/4″ / 743mm25 3/4″ / 654mm201 5/8″1 3/4″ / 44mm
ANSI 900PN15031″ / 787mm27″ / 686mm201 7/8″2″ / 51mm
ANSI 1500PN25036″ / 914mm30 1/2″ / 775mm162 3/4″2 7/8″ / 73mm
FLANGE DIMENSIONS TABLE SIZE (DN) 500 (20″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2027 1/2″ / 699mm25″ / 635mm201 1/8″1 1/4″ / 32mm
ANSI 300PN5030 1/2″ / 775mm27″ / 686mm241 1/4″1 3/8″ / 35mm
ANSI 600PN10032″ / 813mm28 1/2″ / 724mm241 5/8″1 3/4″ / 44mm
ANSI 900PN15033 1/4″ / 845mm29 1/2″ / 749mm202″2 1/8″ / 54mm
ANSI 1500PN25038 3/4″ / 984mm32 3/4″ / 832mm163″3 1/8″ / 79mm
FLANGE DIMENSIONS TABLE SIZE (DN) 600 (24″)
ANSI B16.5ISO 7005 (DIN)DiameterBolt Circle DiameterNumber of BoltsBolt SizeDiameter of Bolt Hole
ANSI 150PN2032″ / 813mm29 1/2″ / 749mm201 1/4″1 3/8″ / 35mm
ANSI 300PN5036″ / 914mm32″ / 813mm241 1/2″1 5/8″ / 41mm
ANSI 600PN10037″ / 940mm33″ / 838mm241 7/8″2″ / 51mm
ANSI 900PN15041″ / 1041mm34″ / 864mm202 1/2″2 5/8″ / 67mm
ANSI 1500PN25046″ / 1168mm39″ / 991mm163 1/2″3 5/8″ / 92mm

All you need to know about Transmitter Flange Size and Class

All you need to know about Transmitter Flange Size and Class

by | Jul 20, 2018

Contents
2
3

Introduction

A Transmitter Flange is an external or internal ridge, or rim (lip), items connected with flanges can be assembled and disassembled easily.

There are many different Transmitter Flange standards to be found worldwide. To allow easy functionality and interchangeability, these are designed to have standardized dimensions. Common world standards include

  • ASA/ASME (USA)
  • PN/DIN (European)
  • BS10 (British/Australian)
  • JIS/KS (Japanese/Korean)
Flanges Standards Versions
DIN Flanges EN FlangesASME FlangesJIS Flanges
German National Standards InstituteEuropean StandardsAmerica Society of Mechanical EngineersJapanese Industry Standard
DIN 2527DIN EN 1092-1:2002-06 and 2007ANSI B 16.5:2009B2220:2004

In the USA, ANSI stopped publishing B16.5 in 1996, and the standard is ASME B16.5

In this article, we mainly talk about ASME and EN-DIN Standard

ASME Standards (U.S.)

ASME (American Society of Mechanical Engineers, of which Australian Pipeline Valve is a member company) is a group of standards, which are in turn covered within the American Standards Institute (ANSI), hence their flanges can be referred to as ANSI or ASME class.

TRANSMITTER FLANGE THAT ARE MADE TO STANDARDS ASME CALLED OUT BY

  • ASME5 (the latest version)
  • ASME B16.47
  • MSS SP-44.

They are typically made from forged materials and have machined surfaces.

TRANSMITTER FLANGE DIMENSION UNDER ASME STANDARD

  • ASME B16.5 refers to nominal pipe sizes(NPS) from ½” to 24″.
  • ASME B16.47 covers NPSs from 26″ to 60″.

TRANSMITTER FLANGE PRESSURE CLASS UNDER ASME STANDARD

  • ASME B16.5 further delineates flanges into seven primary ratings/class: 150 LBS, 300 LBS, 400 LBS, 600 LBS, 900 LBS, 1500 LBS and 2500 LBS.
  • ASME B16.47 delineates its flanges into pressure classes 75 LBS, 150 LBS, 300 LBS, 400 LBS, 600 LBS, and 900 LBS.
  • A Class 300 flange is rated to a higher pressure than a Class 150 flanges, because a Class 300 flange is constructed with more metal and therefore can withstand more pressure. However there are a number of factors that can impact pressure capability of a flange, obviously temperature is one of them.
  • The Pressure Class for flange is often expressed in ‘pounds’. Different names are used to indicate a Pressure Class. For example: 150Lb or 150Lbs or 150#, all mean the same.

TRANSMITTER FLANGE MATERIAL UNDER ASME STANDARD

Materials for flanges are usually under ASME designation including types as below

  • SA-105 : Specification for Carbon Steel Forgings for Piping Applications
  • SA-266: Specification for Carbon Steel Forgings for Pressure Vessel Components
  • SA-182: Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service.

In addition, there are many “industry standard” flanges that in some circumstance may be used on ASME work.

The below two tables are examples of two material groups according to ASTM

ASTM Group 2-1.1 Materials
Nominal DesignationForgingsCastings
C-SiA105 (1)A216 Gr.WCB (1)
C-Mn-SiA350 Gr.LF2 (1)-
3 1/2NiA350 Gr.LF3-
C-Mn-Si-VA350 Gr.LF6 Cl 1 (3)-
NOTES:
(1) Upon prolonged exposure to temperatures above 425ºC, the carbide phase of steel may be converted to graphite. Permissible but not recommended for prolonged use above 425ºC.
(2) Do not use over 260ºC.
ASTM Group 2-1.1 Materials
Nominal DesignationForgingsCastings
16Cr-12Ni-2MoA182 Gr.F316LA351 CF3M
18Cr-13Ni-3MoA182 Gr.F317L-
18Cr-8NiA182 Gr.F304L (1)A351 CF3
NOTES:
(1) Do not use over 425ºC.

Click to Download Corrosion-resistance Reference Sheet of Diaphragms when you choose certain material, the compatibility matter the most.

PRESSURE-TEMPERATURE RATINGS OF TRANSMITTER FLANGE

The above seven primary classes do not correspond to maximum pressures in psi. Instead, the maximum pressure depends on both the material of the flange and the temperature.

For example, the maximum pressure for a Class 150 flange is 285 psi, and for a Class 300 Flange it is 740 psi (both are for ASTM A105 Carbon Steel and temperatures below 100F).

The below 2 tables show ANSI/ASME class 150 to 2500LB pressure/temperature ratings for group 2-1.1 and 2-2.3

Pressure-Temperature Ratings for ASTM Group 2-1.1 Materials
Working pressure by Classes, BAR
Temp.°C15030040060090015002500
-29 to 3819.651.168.1102.1153.2255.3425.5
5019.250.166.8100.2150.4250.6417.7
10017.746.662.193.2139.8233388.3
15015.845.160.190.2135.2225.4375.6
20013.843.858.487.6131.4219365
25012.141.955.983.9125.8209.7349.5
30010.239.853.179.6119.5199.1331.8
3259.338.751.677.4116.1193.6322.6
3508.437.650.175.1112.7187.8313
3757.436.448.572.7109.1181.8303.1
4006.534.746.369.4104.2173.6289.3
4255.528.838.457.586.3143.8239.7
4504.62330.74669115191.7
4753.717.423.234.952.387.2145.3
5002.811.815.723.535.358.897.9
5381.45.97.911.817.729.549.2
Pressure-Temperature Ratings for ASTM Group 2-2.3 Materials
Working pressure by Classes, BAR
Temp.°C15030040060090015002500
-29 to 3815.941.455.282.7124.1206.8344.7
5015.34053.480120.1200.1333.5
10013.334.846.469.6104.4173.9289.9
1501231.441.962.894.2157261.6
20011.229.238.958.387.5145.8243
25010.527.536.654.982.4137.3228.9
3001026.134.852.178.2130.3217.2
3259.325.5345176.4127.4212.3
3508.425.133.450.175.2125.4208.9
3757.424.83349.574.3123.8206.3
4006.524.332.448.672.9121.5202.5
4255.523.931.847.771.6119.3198.8
4504.623.431.246.870.2117.1195.1

European Dimensions EN / DIN/ISO7005

WHAT IS DIN

DIN is a type of Standards

When it comes to German flange manufacturing standards, on the other hand, the governing body is the German Institute of Standardization or Deutsches Institut für Normung (DIN).

WHAT IS DN

DN = Diameter Nominal

The term Diameter Nominal refers to the internal diameter of a pipe. The nominal diameter DN is indicated with reference to the corresponding DIN standard. The metric sizes are stated as ‘DN’ (Nominal Diameter) in mm, equivalent imperial sizing is rounded to the nearest multiple of 25mm (for 2” and over) as below.

1/2″DN152 1/2″DN6512″DN30024″DN600
3/4″DN203″DN8014″DN35028″DN700
1″DN254″DN10015″DN37530″DN750
1 1/4″DN325″DN12516″DN40032″DN800
1 1/2″DN408″DN20018″DN45036″DN900
2″DN5010″DN25020″DN500-

EST4300 Smart Remote Diaphragm Seal PT/DPT use different kind of 1199 Remote Diaphragm Seal Systems (Click to Download Datasheet), the pressure rating have been exactly classified as per above standard.

WHAT IS PN

PN stands for Pressure Nominal and prefixes the pressure rating. PN is the rating designator follower by a designation number indicating the approximate pressure rating in bars, e.g. a PN16 flange is designed to operate up to 16bar.

  • Typical ratings include PN6, PN10, PN16, PN25, PN40, PN64, and PN100.
  • The American ANSI standard refers instead to a pressure / temperature rating termed ‘Class’.
  • PN ratings do not provide a proportional relationship between different PN numbers, whereas ‘Class’ numbers do.
  • Class Ratings based on ASME B16.5 & Corresponding PN Rating:
Flange Class15030040060090015002500
Flange Pressure Nominal, PN205068100150250420

You can also Click Here to check another post in regards of the details of Transmitter Flange diameter, bolts number, bolts circle diameter etc.

WHAT IS THE RELATIONSHIP AMONG BS,EN,DIN & ISO7005

  • British Metric Standard BS4504 is now obsolete and replaced by EN1092-1 edition 09-2008 for steel flanges which also incorporates DIN Standard.
  • Flange drillings in EN1092-1 are generally the same as BS4504 and DIN2501 but EN1092-1 covers a wider range.
  • Most countries in Europe mainly install flanges according to standard DIN EN 1092-1 (forged Stainless or Steel Flanges).
  • ISO 7005 (which AS 4331 is reproduction of) also includes European DIN 2501-1 and BS4504.
  • These flanges are the same as EN1092 but EN1092 also includes higher rated DIN based flanges.
  • Although the standards say they are identical, there are some very minor flange thickness differences between ISO7005 (AS4331) and EN1092.

TRANSMITTER FLANGE UNDER EN/DIN STANDARD

Design According to EN TypeAccording to DIN
Weld Neck Flange Type 11DIN 2627-DIN2638
Blind Flange Type 05DIN 2527
Thread Flange Type 12DIN 2558,DIN2565-DIN2569
Flat Flange Type 01DIN 2573,DIN2576
Lapped Flange Type 02&Type 04DIN2641,DIN2642,DIN2655

TRANSMITTER FLANGE MATERIAL UNDER EN/DIN STANDARD

  • EN 1092-1 is for stainless or steel flanges
  • EN 1092-2 is for iron flanges
  • EN 1092-3 is for alloy flanges
  • EN 1092-4 is for aluminum alloy flanges

4 Types of Thread Process Connections Your Need Know – Part 2/2

4 Types of Thread Process Connections Your Need Know – Part 2/2

by | Jan 24, 2018

All You Need to Know About Thread Process Connections
THE GUIDE IN 2021
Contents
2
3

Introduction

Threaded connections are a widely used and cost-effective solution for joining pressure sensors to equipment. They offer installation flexibility and can easily be adjusted or removed in case of maintenance. Some common thread types include NPT, BSP, and Metric. Tightening torque should be carefully considered when installing threaded connections, as it directly impacts the effectiveness of the seal.

The most widely used thread types for pressure sensor connections include

  1. National Pipe Thread (NPT),
  2. British Standard Pipe (BSP),
  3. Metric threads. Standards:

The American National Standards Institute (ANSI) regulates NPT threads, British Standard Institute (BSI) oversees BSP threads, and the International Organization for Standardization (ISO) governs Metric threads.

For more details about these three, please click to check.

Aside from the previously mentioned NPT, BSP, and Metric threads, several other thread types can be utilized in pressure sensor connections. Some of these include:

SAE Straight Thread (also known as O-ring Boss or ORB):

This thread type features a straight thread and an O-ring to create a tight seal. SAE J1926 regulates these threads, which are widely used in hydraulic systems. The O-ring ensures that a leak-proof seal is formed, providing reliable performance and minimizing the risk of leakage.

UN/UNF (Unified National/Unified National Fine):

These thread types conform to the Unified Thread Standard (UTS) and are denoted as either coarse thread (UN) or fine thread (UNF). They are commonly used in the United States and Canada for various applications, including pressure sensors.

JIC (Joint Industrial Council) Fittings:

Although not a thread type, these fittings feature a 37-degree flare, which forms a tight seal when connecting to a JIC flared female fitting. They are designed to handle high pressure and are commonly used in hydraulic systems.

Table: Key information on threaded connections for pressure sensors

Thread TypeStandardHighlight FeaturesCommon MaterialsLimitationsSuitable Industries
NPT (National Pipe Thread)ANSIEasy installation, tapered design for tight fitStainless steel, brass, carbon steel, Hastelloy, MonelPotential for leaks, not suitable for ultra-high pressureOil and gas, water treatment, HVAC, process industries
BSP (British Standard Pipe)BSIParallel and tapered types available, globally recognizedStainless steel, brass, carbon steel, Hastelloy, MonelRequires thread sealant, not ideal for high-pressure applicationsOil and gas, water treatment, HVAC, process industries
MetricISOGlobally recognized, various pitch optionsStainless steel, brass, carbon steel, Hastelloy, MonelNot universally compatible, may require thread sealantAutomotive, industrial machinery, process industries
SAE Straight Thread (O-ring Boss)SAE J1926Straight thread with O-ring seal, high-pressure compatibilityStainless steel, brass, carbon steel, Hastelloy, MonelLimited adjustability due to O-ringHydraulic systems, aerospace, automotive
UN/UNF (Unified National, Coarse/Fine)ASME B1.1Coarse and fine thread options, widely used in North AmericaStainless steel, brass, carbon steel, Hastelloy, MonelNot universally compatible, may require thread sealantAutomotive, industrial machinery, aerospace
G-series (ISO/BSP Parallel)ISO 228Parallel design, requires gasket or O-ring for sealingStainless steel, brass, carbon steel, Hastelloy, MonelNot ideal for high-pressure applications, requires separate sealWater treatment, HVAC, automotive, process industries
JIC (Joint Industrial Council) FittingsSAE J51437-degree flare for tight seal, high-pressure compatibilityStainless steel, brass, carbon steel, Hastelloy, MonelSpecialized design, not a threaded connectionHydraulic systems, aerospace, automotive

To ensure optimal performance and a reliable seal, following proper installation guidelines for threaded process connections is crucial. Start by selecting the correct thread type and size for your application.

When installing, use the manufacturer-recommended torque to tighten the connection, preventing over-tightening or under-tightening, which can result in leaks or damage to the threads. Thread sealants, such as Teflon tape or liquid threadlocker, should be applied according to the manufacturer’s instructions to ensure a leak-free connection.

A Comprehensive Guide to Thread Types

As a mechanical and electrical engineer, I understand the importance of the right thread type for pressure sensors. This blog post aims to provide you with detailed, valuable, and specific information about various thread types, ensuring you make the best decision for your application. We will discuss **NPT, G, M, and R** thread types and other less common options.

1, NPT Threads

NPT1/2, NPT1/4, and NPT1/8

National Pipe Taper (NPT) threads are the most common type for pressure sensors in North America. The **tapered design** creates a tight seal when the male and female threads are engaged. The three most common sizes are:

NPT1/2: This is the **most popular** size, with a nominal diameter of 0.5 inches (12.7 mm) and a thread pitch of 14 threads per inch (TPI). It is suitable for medium to high-pressure applications, handling pressures up to **1500 psi (10.34 MPa)**.

NPT1/4: With a nominal diameter of 0.25 inches (6.35 mm) and a thread pitch of 18 TPI, it’s ideal for low to medium-pressure applications. The maximum pressure rating is **1000 psi (6.89 MPa)**.

NPT1/8: This size has a nominal diameter of 0.125 inches (3.18 mm) and a thread pitch of 27 TPI. It is typically used for low-pressure applications, with a maximum pressure rating of **500 psi (3.45 MPa)**.

2, G Threads

G1/2, G1/4

As we discussed before, G threads, also known as BSP (British Standard Pipe) threads, are widely used in Europe, Asia, and other regions outside North America. They have a parallel design and rely on a gasket or O-ring for sealing. The two most common sizes include:

G1/2: This size has a nominal diameter of 0.5 inches (12.7 mm) and a thread pitch of 14 TPI. It is suitable for medium to high-pressure applications, with a maximum pressure rating of 1500 psi (10.34 MPa).

G1/4: With a nominal diameter of 0.25 inches (6.35 mm) and a thread pitch of 19 TPI, it is ideal for low to medium pressure applications. The maximum pressure rating is 1000 psi (6.89 MPa).

3, M Threads

M20x1.5, M12x1.5

Metric (M) threads are another parallel thread type commonly used in pressure sensors. They are designated by their nominal diameter (in millimeters) followed by the thread pitch. The two most popular sizes are:

M20x1.5: This size has a nominal diameter of 20 mm and a thread pitch of 1.5 mm. It is suitable for medium to high-pressure applications, with a maximum pressure rating of 1500 psi (10.34 MPa).

M12x1.5: With a nominal diameter of 12 mm and a thread pitch of 1.5 mm, it is ideal for low to medium pressure applications. The maximum pressure rating is 1000 psi (6.89 MPa).

4, R Threads

R1/4, R1/8

R threads, also known as **PT (Pipe Taper) threads**, are a variant of the BSP thread family. They have a **tapered design** similar to NPT threads but follow a different standard. The two most common sizes include:

R1/4: This size has a nominal diameter of 0.25 inches (6.35 mm) and a thread pitch of 19 TPI. It is suitable for low to medium pressure applications, with a maximum pressure rating of 1000 psi (6.89 MPa).

R1/8: With a nominal diameter of 0.125 inches (3.18 mm) and a thread pitch of 28 TPI, it is ideal for low-pressure applications. The maximum pressure rating is 500 psi (3.45 MPa).

5, Others

Other thread types are available for pressure sensors, such as UNF (Unified Fine) and UNEF (Unified Extra Fine) threads. These types are less common but may be suitable for specific applications. Consult a specialist if you need a unique thread type.

Thread Type Selection Table

Thread TypeNominal DiameterThread PitchMax Pressure Rating
NPT1/20.5 in (12.7 mm)14 TPI1500 psi (10.34 MPa)
NPT1/40.25 in (6.35 mm)18 TPI1000 psi (6.89 MPa)
NPT1/80.125 in (3.18 mm)27 TPI500 psi (3.45 MPa)
G1/20.5 in (12.7 mm)14 TPI1500 psi (10.34 MPa)
G1/40.25 in (6.35 mm)19 TPI1000 psi (6.89 MPa)
M20x1.520 mm1.5 mm1500 psi (10.34 MPa)
M12x1.512 mm1.5 mm1000 psi (6.89 MPa)
R1/40.25 in (6.35 mm)19 TPI1000 psi (6.89 MPa)
R1/80.125 in (3.18 mm)28 TPI500 psi (3.45 MPa)

At last,  understanding the differences between various thread types and their respective pressure ratings is crucial when selecting the appropriate pressure sensor for your application.

By considering the information provided in this and the previous guide, you can make an informed decision and ensure the best performance in your system.

4 Types of Thread Process Connections Your Need Know

4 Types of Thread Process Connections Your Need Know

by | Dec 21, 2017

All You Need to Know About Thread Process Connections
THE GUIDE IN 2021
Contents
2
3

Back in the 19th century, screw Threads Process Connections come in a great variety and are incompatible. Nowadays, thanks to the efforts made by people committing to standardizing process connections threads, choices are nailed down to a few when choosing a pressure transmitter. In what follows, three types of thread are introduced: BSP, NPT, and UNF.

British Standard Pipe

BSP, British Standard Pipe, was created by Joseph Whitworth in the middle of 19th century and is now widely accepted from Europe to Asia, in particular in the UK. BSP is a type of parallel thread and the pressure tight seal is enabled with a sealing washer, which is made of different materials depending on the pressure and the medium being used. The most common sizes are ¼ or ½ inch BSP.

1/2"BSP MALE1/2"G EN837 DIN16288
1_2'BSP MALEEN83701 G_2B G1_2A DIN 16288 FORM B
1/4"G EN837 DIN162881/4"G DIN3852
1_4'BSP EN837 DIN162881_4'G DIN3852-2
BSPP (G)BSPT (R/Rp)
Thread size (inch)Major Diameter (mm)Minor Diameter (mm)TPIMale Thread size
(inch)		Female Thread size
(inch)		Major Diameter (mm)Minor Female
Diameter (mm)		TPI
G 1/16”7,7236,56128R 1/16”Rp 1/16”7,7236,49028
G 1/8”9,7288,56628R 1/8”Rp 1/8”9,7288,49528
G 1/4”13,15711,44519R 1/4”Rp 1/4”13,15711,34119
G 3/8”16,66214,95019R 3/8”Rp 3/8”16,66214,84619
G 1/2”20,95518,63114R 1/2”Rp 1/2”20,95518,48914
G 3/4”26,44124,11714R 3/4”Rp 3/4”26,44123,97514
G 1”33,24930,29111R 1”Rp 1”33,24930,11111
G 2”59,61456,65611R 2”Rp 2”59,61456,47611

National Pipe Taper

In the USA, NPT (National Pipe Tapered) is the most popular process connection, especially in businesses of oil and petroleum. Compared with BSP, NPT is easier to cut and user-friendly, and is considered a booster to American Industrial Revolution. Being a kind of screw thread system, NPT is tapered thread with the pressure tight seal being made on the thread itself. The most common sizes are 1/4, or 1/2 inch NPT.

1/2"NPT MALE1/4"NPT MALE
1_2'NPT MALE1_4'NPT MALE
1/4"NPT FEMALE1"NPT SEALED
1_4'NPT FEMALE1'NPT SEALED
Thread sizeMajor Diameter (mm)TPI
1/16” – 27 NPT7,93827
1/8” – 27 NPT10,28727
1/4” – 18 NPT13,71618
3/8” – 18 NPT17,14518
1/2” – 14 NPT21,33614
3/4” – 14 NPT26,67014
1” – 11 ½ NPT33,40111,5
2” – 11 ½ NPT60,32511,5

Unified Thread Standard

William Sellers also developed what became the Unified Thread Standard. Straight thread Process Connections known as SAE are now called UNF (Unified National Fine) under the Unified Thread Standard.

A common variation of this Process Connections is the M/F-250, or the autoclave fitting. This fitting has a cone at the end of it for pressure ranges above 10,000 psi. It is also commonly referred to as a Sno Trik® fitting as well – though that is a brand name.

The most common types of UN (Unified National) thread are:

  1. UNC – Unified National Coarse Thread, comparable with the ISO metric thread.
  2. UNF – Unified National Fine Thread.

*Compared to standard threads (coarse thread), a fine thread has a smaller pitch.

Unified threads come in three different classes:

  1. 1A (external) & 1B (internal): for applications where a liberal tolerance is required to permit easy assembly even with slightly nicked threads.
  2. 2A (external) & 2B (internal): most commonly used class for general applications
  3. 3A (external) & 3B (internal): for applications where closeness of fit and/or accuracy of thread elements are important.
UNC (2A)UNF (2A)
Nominal DiameterMajor Diameter (mm)Minor Diameter (mm)TPINominal DiameterMajor Diameter (mm)Minor Diameter (mm)TPI
1/4” x 20 UNC6,3224,978201/4” x 28 UNF6,3255,36028
5/16” x 18 UNC7,9076,401185/16” x 24 UNF7,9106,78224
3/8” x 16 UNC9,4917,798163/8” x 24 UNF9,4978,38224
7/16” x 14 UNC11,0769,144147/16” x 20 UNF11,0799,72820
1/2” x 13 UNC12,66110,592131/2” x 20 UNF12,66711,32820
5/8” x 11 UNC15,83413,386115/8” x 18 UNF15,83914,35118
3/4” x 10 UNC19,00416,307103/4” x 16 UNF19,01217,32316
7/8” x 9 UNC22,17619,17797/8” x 14 UNF22,18420,26914
1” x 8 UNC25,34921,97181” x 12 UNF25,35423,11412
2” x 4,5 UNC50,72644,6794.5

ISO Metric Screw Thread

The ISO metric screw threads are the world-wide most commonly used type of general-purpose screw thread. They were one of the first international standards agreed when the International Organization for Standardization was set up in 1947.

The “M” designation for metric screws indicates the nominal outer diameter of the screw, in millimeters (e.g., an M6 screw has a nominal outer diameter of 6 millimeters). (Source from Wikipedia)

ISO 262 selected sizes for screws, bolts and nuts
Nominal diameter D (mm)Pitch P (mm)Nominal diameter D (mm)Pitch P (mm)
1st choice2nd choiceCoarseFine1st choice2nd choiceCoarseFine
10.250.21621.5
1.20.250.2182.52 or 1.5
1.40.30.2202.52 or 1.5
1.60.350.2222.52 or 1.5
1.80.350.22432
20.40.252732
2.50.450.35303.52
30.50.35333.52
3.50.60.353643
40.70.53943
50.80.5424.53
610.75454.53
710.754853
81.251 or 0.755254
101.51.25 or 1565.54
121.751.5 or 1.25605.54
1421.56464

Comparison for Thread Process Connections:

COMPARISON SHEET (M – BSPP – BSPT – NPT – UNC - UNF)
UNC (2A)
Metric: Standard/FineInch: BSPP (G)BSPT (R)NPTUNC/UNF
TypeParallelParallelTaperedTaperedParallel
Flank angle60°55°55°60°60°
Thread angle0°0°1°47’1°47’0°
Seal locationO-ring/ Gasket/ConeO-ring/ Gasket/ConeOn threadsOn threadsO-ring/ Gasket/Cone
COMPARISON SHEET (M – BSPP – BSPT – NPT – UNC - UNF)
Major Diameter (mm):
BSPP (G)BSPT (R/Rp)NPTUNCUNF
1/16”7,7237,7237,938
1/8”9,7289,72810,287
1/4”13,15713,15713,7166,3226,325
3/8”16,66216,66217,1459,4919,497
1/2”20,95520,95521,33612,66112,667
3/4”26,44126,44126,67019,00419,012
1”33,24933,24933,40125,34925,354
2”59,61459,61460,32550,726-
Minor Diameter (mm):
BSPP (G)BSPT (R/Rp)UNCUNF
1/16”6,5616,490
1/8”8,5668,495
1/4”11,44511,3414,9785,360
3/8”14,95014,8467,7988,382
1/2”18,63118,48910,59211,328
3/4”24,11723,97516,30717,323
1”30,29130,11121,97123,114
2”56,65656,47644,679-
TPI (Treads per inch):
BSPP (G)BSPT (R/Rp)NPTUNCUNF
1/16”282827
1/8”282827
1/4”1919182028
3/8”1919181624
1/2”1414141320
3/4”1414141016
1”111111,5812
2”111111,54,5-

How to Choose Thread Process Connections

There are no criteria to judge which Thread Process Connections mentioned above is better. Actually, each of them appears at a proper time with a proper reason. When it comes to choose a process connection, what really matters is the pipe fitting your pressure transducer is to be used.  It is true that different country has its own standards and it is also a fact that any thread standard is available worldwide.

If you need help in finding what your need. Contact Us! We are always ready to give your support in choosing pressure sensor Thread Process Connections.

Thread Permissible maximum pressure
Cu-alloyStainless steelMonel®
bar
psi
bar
psi
bar
psi
BSP ⅛ (G⅛)4006,00040060004006,000
BSP ¼ (G¼)6008,6001,00015,0001,00015,000
BSP ⅜(G⅜)6008,6001,00015,0001,00015,000
BSP ½ (G½)1,00015,0002,50036,0002,50036,000
M10 x 14006,0004006,0004006,000
M12 x 1.54006,0004006,0004006,000
M20 x 1.51,00015,0002,50036,0002,50036,000
⅛ NPT, R ⅛4006,0004006,0004006,000
¼ NPT, R ¼6008,6001,00015,0001,00015,000
⅜ NPT, R ⅜6008,6001,00015,0001,00015,000
½ NPT, R ½1,00015,0001,60023,0001,60023,000
7/16-20 UNF4006,00080012,00080012,000
The specified values for the maximum pressure are rounded values and are assigned to the nearest standard scale range.
Thread Glossary
ASMEThe American Society of Mechanical Engineers (ASME)
BSPPBritish Standard Pipe Parallel per ISO 228/1
BSPTBritish Standard Pipe Tapered per EN 10226-1. See ISO 7/1.
DINDeutsche Institut für Normung e.V.
ISO 228/1International Standards Organization Specification 228/1, straight threads, reference specification: BSPP, DIN 259, JIS B0202.
JISJapanese Industrial Standard
MetricISO Metric thread is a globally standardized thread
NPTNational Pipe Tapered.
SAESociety of Automotive Engineers
UNUnified Constant-Pitch Thread Series
UNC/UNRCUnified Coarse Thread Series
UNEF/UNREFUnified Extra-Fine Thread Series
UNF/UNRFUnified Fine Thread Series
UNRMale Screw Thread only
UNS/UNRSSelected special combinations of diameter, pitch, and length of engagement
PitchFor the purposes of this guide, pitch refers to threads per inch, instead of the distance between the threads, for fractional screw threads and pipe threads. For all metric screw threads, pitch refers to the distance between adjacent threads.