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BSPP, BSPT, R and Rc threads are different types of threaded connections that play an important role in industry and plumbing. Understanding the differences and characteristics of these threads is critical to properly selecting the connection type for a particular application. The main differences between BSPP, BSPT, R and Rc threads are described below.
What is BSPP thread?
BSPP thread refers to British Standard Pipe Parallel (British Standard Pipe Parallel), also known as G thread. It is a parallel thread, the shape of the thread is straight and the pitch is equal. BSPP threads are commonly used to join fittings and piping systems.
BSPP gauges have longer male threads and use a copper extruded gasket that is squeezed between the bottom of the male fitting and the bottom of the female BSPP hole to create a pressure tight seal. Ralston Instruments has Male BSPP Adapters, Female BSPP Adapters, Female BSPP Gauge Adapters and Female BSPP Quick Disconnect Gauge Adapters.
Basic features of BSPP
Parallel thread shape, parallel to the axis.
The pitches are equal and the number of threads is fixed.
Seal the connection with a gasket or apply a sealant.
Suitable for applications with non-sealed connections.
Provides a solid connection and has a high withstand voltage capability.
BSPP Thread Design and Dimensions
Thread type: BSPP thread is a parallel thread, also known as G thread.
Thread parameters: The standard of BSPP thread is based on imperial units, mainly including pitch (P) and tooth height (H). The pitch is usually expressed in per inch (TPI, Threads Per Inch) or per millimeter (MM).
Thread size: The size of BSPP thread is determined according to pipe diameter (D) and pitch (P). Common thread sizes include 1/8", 1/4", 3/8", 1/2", 3/4", 1", 1-1/4", 1-1/2", 2", etc. .
Thread angle: The thread angle of BSPP thread is 55 degrees.
Application field of BSPP thread
Hydraulic system: BSPP threads are often used to connect hydraulic pipe fittings and hydraulic valves to establish pipeline connections for hydraulic systems. They provide a secure connection for transfer piping in medium and high pressure hydraulic systems.
Pneumatic system: In pneumatic system, BSPP thread is used to connect pneumatic pipe fittings and pneumatic valves. This threaded connection achieves reliable gas-tightness for the transmission and control of gases.
Low-pressure liquid transmission system: Due to the high pressure resistance of BSPP threads, they are often used in low-pressure liquid transmission systems, such as fuel transmission pipelines, liquid supply pipelines, etc.
Industrial Equipment and Machinery: BSPP threads are used to connect pipes and fittings for industrial equipment and machinery. For example, connect water pumps, compressors, cylinders, filters and other equipment.
The sealing method and main points of BSPP thread
Sealing method: The connection of BSPP thread is usually sealed by gasket or coating sealant. A gasket sits between two surfaces of a threaded connection and creates a seal through compression. Another method is to apply a sealant on the surface of the thread, and when the thread is connected, the sealant fills the gap and provides a sealing effect.
Gasket Selection: Gaskets play a key role in BSPP threaded connections. Gaskets of suitable materials, such as rubber, polytetrafluoroethylene (PTFE), etc., should be selected to ensure good sealing performance. The size and material of the gasket should match the thread specification.
Sealant Application: Applying a sealant is another common sealing method. Apply a sealant, such as polymer sealant or thread sealant, to the external surfaces of BSPP threads. When threads are joined, the sealant fills the thread gaps and forms a sealant.
Key points for fastening: The fastening strength of BSPP threaded connection is critical. Proper tightening force can ensure the stability and tightness of the threaded connection. It should be noted that over-tightening may result in damage to the gasket or excessive deformation of the thread, thereby affecting the sealing performance.
Periodic Inspection: In order to maintain a good seal on BSPP threaded connections, it is important to periodically inspect the connections for looseness or leaks. The gasket or sealant can be retightened or replaced if necessary.
Advantages and disadvantages of BSPP thread
Advantage:
Easy installation and easy alignment saves installation time and effort.
Provides a solid connection for applications that require reliability.
Maintenance is relatively simple, and can be performed by loosening and tightening the threaded connection and replacing the gasket or applying sealant.
Shortcoming:
Tightness relies on gaskets or sealants, and aging, damaged gaskets, or sealant failures can cause leakage problems.
Limited capacity in high-pressure applications, exceeding the specified pressure range may cause problems with leakage or thread deformation.
What is BSPT thread?
BSPT thread refers to British Standard Pipe Taper (British Standard Pipe Taper), also known as R thread. It is a tapered thread, the standard thread type often used for pipe connections and seals.
BSPT (British Standard Pipe Taper) is similar to NPT, but has important differences. The angle of the thread flank (if you cut the joint in half lengthwise and measure from root to crest to root) is 55 degrees instead of 60 degrees for NPT. Another important difference is that for many BSPT pipe sizes, the thread pitch is different from NPT. Therefore, NPT male threads will sometimes fit into BSPT fittings and vice versa, but they will not seal.
Characteristics of BSPT thread
Conical thread shape, the thread line is tapered, and the pitch is uneven.
The thread angle is 55 degrees, which is used to ensure the firmness and sealing of the connection.
Sealing paste or lubricants are usually used to achieve sealing.
Provide better sealing performance, suitable for application scenarios that require higher sealing requirements.
BSPT Thread Design and Dimensions
Thread type: BSPT thread is a tapered thread, also known as R thread.
Thread parameters: The standard of BSPT threads is based on imperial units, mainly including pitch (P) and thread height (H). The pitch is usually expressed in per inch (TPI, Threads Per Inch) or per millimeter (MM).
Thread size: The size of BSPT thread is determined according to pipe diameter (D) and pitch (P). Common thread sizes include 1/16", 1/8", 1/4", 3/8", 1/2", 3/4", 1", 1-1/4", 1-1/2 ", 2", etc.
Thread Angle: BSPT thread has a thread angle of 55 degrees.
Application range of BSPT thread
Water pipe system: BSPT threads are often used to connect water pipes and fittings, such as water supply pipes, drainage pipes and water supply systems. They provide a reliable airtight connection and are suitable for general low pressure water piping systems.
Gas piping: BSPT threads are also suitable for gas piping systems such as gas piping and liquefied petroleum gas (LPG) piping. They provide a reliable connection and meet the safety requirements of gas pipelines.
Air compression system: BSPT threads are widely used in air compression systems, including the connection of compressors, cylinders, filters, and pressure regulators. They can withstand the pressure of compressed air and provide a reliable connection.
Industrial equipment and machinery: BSPT threads are used to connect pipes and fittings of various industrial equipment and machinery, such as pumps, valves, cooling systems, etc. They are suitable for the transmission and control of general low pressure liquids and gases.
Sealing method and key points of BSPT thread
Sealant or Lubricant: BSPT threads are usually sealed with a sealant or lubricant. Applying a sealant or lubricant prior to threading can fill the thread gaps and provide a good seal. This method prevents leaks and loosening.
Appropriate tightening force: BSPT thread connection requires appropriate tightening force to ensure the tight connection and sealing performance of the thread. Too little tightening force may cause leakage, and too much tightening force may cause thread damage or deformation.
Sealant Selection: It is very important to select the proper sealant or lubricant. According to specific application requirements, choose products with good sealing and high temperature or corrosion resistance.
Pay attention to thread quality: ensure that the quality and size of BSPT threads meet the standard requirements to ensure the reliability of sealing performance. Bad threads can cause leaks or connection failures.
Advantages and Limitations of BSPT Threads
Advantage:
Reliable sealing performance, effectively prevent leakage through sealing paste or lubricant.
High pressure bearing capacity, suitable for general low pressure liquid and gas transmission system.
Relatively simple maintenance can be carried out by reapplying sealant or lubricant, adjusting the tightening force, etc.
Limit:
Reliance on sealant paste or lubricants can lead to leakage problems if the lubricant fails or the sealant ages.
Limited application pressure range beyond which leakage or thread deformation may occur.
Not suitable for frequent disassembly and re-use, requiring reapplication of sealant or lubricant each time the threads are tightened.
Overview of R and Rc threads
R thread (R Series) is the abbreviation of British Standard Pipe Taper, also known as BSPT thread. It is a conical thread with a tapered thread line and uneven pitch. The R thread is usually sealed with a sealant or lubricant and is suitable for low-pressure liquid and gas transmission systems. It is widely used in water pipe system, gas pipeline, air compression system and industrial equipment and other fields.
Rc thread (Rc Series) is the abbreviation of British Standard Pipe Taper Internal. It is an internally threaded version of the R thread and is also a tapered thread that accepts the male threaded connection of the R thread. Rc threads are usually used inside pipe fittings to receive external threaded connections. Similar to the R thread, the Rc thread is also suitable for low pressure liquid and gas transmission systems.
The design and dimensions of R and Rc threads vary according to specific standards and codes. When selecting and using R and Rc threads, it is necessary to ensure compliance with the corresponding standards, and to select according to specific application requirements and pressure conditions.
The difference and characteristics of R and Rc thread
The difference:
External and internal: R thread is external thread, used for external connection; while Rc thread is internal thread, used to receive external thread connection.
Installation method: R thread requires external thread to cooperate with it, while Rc thread requires internal thread to cooperate with it.
Application scenario: R thread is often used for external pipeline connections, such as water pipe systems, gas pipelines, etc.; Rc thread is often used inside pipe fittings to receive external thread connections.
Features:
Tapered thread: Both R and Rc threads belong to the type of tapered thread, the thread line is tapered, and the pitch is uneven.
Sealing method: R and Rc threads are usually sealed with sealing paste or lubricant, which can provide good sealing performance.
Applicable pressure: R and Rc threads are suitable for low-pressure liquid and gas transmission systems, with limited bearing capacity, not suitable for high-pressure applications.
Application range: R thread is widely used in external pipe connections, while Rc thread is often used inside pipe fittings, such as flanges and sockets that receive external threads.
Application Scenarios of R and Rc Threads
Scenarios for using R thread:
Water pipe system: R thread is often used for the connection of water pipe systems, such as water supply pipes, drainage pipes and water supply systems. They provide a reliable airtight connection and are widely used in low pressure liquid transfer.
Gas pipeline: R thread is also suitable for gas pipeline system, including gas pipeline and liquefied petroleum gas (LPG) pipeline, etc. They provide a reliable connection and meet the safety requirements of gas pipelines.
Air compression system: R threads are widely used in air compression systems, including the connection of compressors, cylinders, filters, and pressure regulating valves. They can withstand the pressure of compressed air and provide a reliable connection.
Industrial equipment and machinery: R threads are often used to connect pipes and fittings of various industrial equipment and machinery, such as pumps, valves, cooling systems, etc. They are suitable for the transmission and control of general low pressure liquids and gases.
Usage scenarios of Rc thread:
Inside of pipe fittings: Rc threads are mainly used inside pipe fittings to receive external threaded connections. They are typically used inside fittings such as flanges, sockets, etc. that receive external threads.
Flange connection: Rc thread is often used in internally threaded holes in flange connections to receive externally threaded flange bolts and nuts.
Sealing mechanism and advantages of R and Rc threads
Sealing mechanism:
Sealing mechanism of R thread: R thread usually uses sealing paste or lubricant to achieve sealing. Applying a sealant or lubricant prior to threading can fill the thread gaps and provide a good seal. This method prevents leaks and loosening.
Sealing mechanism of Rc thread: The sealing mechanism of Rc thread is similar to that of R thread, and sealing paste or lubricant is also required to achieve sealing. By applying sealing paste or lubricant, the thread gap can be filled to ensure the sealing performance of the connection.
Advantage:
Good sealing performance: R and Rc threads use sealing paste or lubricant to achieve sealing, which can provide good sealing performance and effectively prevent leakage.
Easy maintenance and disassembly: R and Rc threaded connections are easy to maintain due to the use of sealing paste or lubricant. When the connection needs to be disassembled, a lubricant or sealant can lubricate and prevent thread damage.
BSPP vs BSPT vs R and Rc Thread Comparison
Structural form: BSPP thread is a parallel pipe thread, BSPT thread is a conical pipe thread, and R thread and Rc thread are circular threads.
Sealing method: The sealing of BSPP thread is realized by gasket or O-ring, the sealing of BSPT thread is realized by the metal-to-metal contact between threads, and the sealing of R thread and Rc thread usually relies on embedded sealant or Other sealing materials.
Applications: BSPP threads are typically used in high-pressure applications, such as hydraulic systems, while BSPT threads are typically used in low-pressure applications, such as gas pipelines. R and Rc threads are commonly used for low pressure and general applications such as water pipes and air compressors.
Regional Standards: BSPP and BSPT threads are imperial standards of weights and measures, common in the United Kingdom and some other countries. R threads and Rc threads are common in Japan and some other countries.
Connection Types and Suitability Comparison
BSPP threads are suitable for high-pressure liquid pipe connections, commonly found in hydraulic systems and other high-pressure fluid transfer applications.
BSPT threads are suitable for low-pressure gas pipe connections, commonly found in gas transmission and some low-pressure liquid applications.
R thread and Rc thread are suitable for general low-pressure liquid and gas pipeline connections, such as water pipes, air compressors, etc.
Comparison of sealing performance and installation requirements
Sealing performance:
BSPP threads: BSPP threads generally have better sealing properties, especially if gaskets or O-rings are used. They provide a reliable seal against liquid or gas leakage.
BSPT threads: The sealing performance of BSPT threads relies on the metal-to-metal contact between the threads to provide a certain degree of sealing performance. However, in liquid applications there may be a risk of leakage.
R thread and Rc thread: R thread and Rc thread usually require embedded sealant or other sealing material to achieve sealing. Their sealing performance depends on the sealant used and can provide a certain sealing performance .
Installation requirements:
BSPP Threads: BSPP threads are relatively simple to install and usually only require tightening with an appropriate wrench or wrench tool. However, you need to ensure that the thread type and size are selected correctly and that proper torque specifications are followed during installation.
BSPT thread: BSPT thread has higher installation requirements. When installing, the metal-to-metal contact between threads needs to be properly handled to ensure good sealing performance.
R thread and Rc thread: The installation of R thread and Rc thread is relatively simple, similar to general thread connection. However, when installing, it is necessary to ensure the correct selection of thread type and size, and pay attention to the correct use of embedded sealant or other sealing materials.
Elements and Considerations for Selecting the Proper Thread
When selecting the appropriate thread type, factors such as application needs, standards and codes, sealing requirements, installation and maintenance, material compatibility, and availability and cost need to be considered. Understanding the application needs and the standards in your area is key to ensure the thread type selected meets the requirements. Sealing performance and installation requirements are also important considerations, and reasonable choices need to be made according to application needs and connection conditions.
Conclusion:
BSPP, BSPT, R and Rc threads are different connection types, each with unique characteristics and applicability. Proper selection of the appropriate thread type is critical to ensuring a safe and reliable connection. By understanding the difference between BSPP, BSPT, R and Rc threads, we can better select the type of connection that suits our specific needs and ensure the safe and efficient operation of our piping system. Of course, if you still have questions, please feel free to contact us!
