Parallel Threads: Reusable and Reliable, or Tapered Threads: The One-Time Wonder?

Threads are a common means of joining two parts together in the field of mechanical engineering and manufacturing. There are two main types of threads: parallel and tapered (conical). Each type of thread has its unique sealing function and features that make it suitable for different applications. In this article, we will explore the theoretical sealing function of parallel threads with sealing rings and tapered threads with one-time-use sealing. We will also look at the features of each type of thread and how to tell them apart practically. Additionally, we will provide a practical example of a cam and groove adapter with both parallel and tapered connections.

Sealing Function

The sealing function of parallel threads is achieved through the use of sealing rings. These rings are typically made of rubber or silicone and are placed in a groove on the female thread. When the male thread is screwed in, the sealing ring is compressed, creating a tight seal between the two parts.

On the other hand, tapered thread connections are achieved by screwing a male thread into a female thread with a conical shape. As the threads tighten, the conical shape compresses and creates a tight seal. The taper angle and the thread pitch are important factors in determining the sealing function of a tapered thread connection. Tapered threads are commonly used in applications where a tight seal is needed, such as in plumbing and hydraulic systems. Ttapered threads rely on a one-time-use sealing method. This means that the threads themselves are designed to create a seal when tightened. Tapered threads have a conical shape that allows the threads to wedge together as they are tightened. This creates a tight seal that prevents leaks.

Sealing Features

Parallel threads have the advantage of being reusable. The use of sealing rings makes it possible to create a tight seal even after multiple uses. Additionally, parallel threads are typically easier to tighten and loosen, making them more convenient to work with.

Tapered threads, on the other hand, have a wider range of temperature and pressure capabilities. The conical shape of the threads allows them to create a tight seal even at high temperatures and pressures. However, tapered threads are not reusable and require a new seal each time they are used.

How to Tell Them Apart Practically

One of the easiest ways to tell parallel and tapered threads apart is to look at their shape. Parallel threads have a constant diameter along their length, whereas tapered threads have a gradually increasing or decreasing diameter along their length. Additionally, tapered threads typically have a 60-degree angle, while parallel threads have a 55-degree angle.

When working with threaded parts, it is essential to match the thread types correctly. Mismatched threads can result in leaks, damage to the parts, and other problems. One way to ensure that the threads match is to use a thread gauge. A thread gauge is a tool that is used to measure the size and pitch of a thread. By using a thread gauge, you can determine the type of thread and ensure that the parts are compatible.

Cam and Groove Adapter Example

A cam and groove adapter is a type of coupling that is commonly used to connect hoses, pipes, and other fluid transfer equipment. The adapter consists of two parts: a male and a female. The male part has a groove that locks into the female part's cam, creating a secure connection. The adapter can be used with both parallel and tapered threads.

When using a cam and groove adapter with a female BSPP connection and a male BSPT thread, it is essential to ensure that the threads match correctly. The female BSPP connection has parallel threads, whereas the male BSPT thread has tapered threads. To ensure a tight seal, a sealing insertion can be used with the female BSPP connection. The sealing insertion is a metal ring that fits into the female thread and provides a surface for the tapered male thread to seal against.

When using a camlock adapter with parallel threads, such as EN14420-7 and DIN 2828, a sealing ring can be used to create a tight seal. The sealing ring is typically made of rubber or silicone and is placed in a groove on the female thread. When the male thread is screwed in, the sealing ring is compressed, creating a tight seal between the two.

In conclusion, parallel and tapered threads are two common types of threads used in mechanical engineering and manufacturing applications. The sealing function of parallel threads is achieved through the use of sealing rings, whereas tapered threads rely on a one-time-use sealing method. Parallel threads have the advantage of being reusable, while tapered threads have a wider range of temperature and pressure capabilities.

It is essential to match the thread types correctly when working with threaded parts to ensure a tight seal and prevent leaks. A thread gauge can be used to determine the type of thread and ensure compatibility between the parts.

The use of cam and groove adapters is common in fluid transfer applications. When using a cam and groove adapter with parallel or tapered threads, it is important to use the correct sealing method. A sealing ring can be used with parallel threads, while a sealing insertion can be used with tapered threads to ensure a tight seal.

Summary

In summary, understanding the differences between parallel and tapered threads is crucial in ensuring proper use and compatibility of threaded parts. While parallel threads offer reusability and reliability, tapered threads are a one-time wonder with a wider range of temperature and pressure capabilities. Ultimately, the choice between parallel and tapered threads depends on the specific application and sealing requirements.