Common threads for instruments
Thread Content
What are the common thread types for instruments? There are G threads, M threads, NPT – are there any others? I’ll give you a fitting – how can you tell what type of thread it is and approximately what its size is? What are the common types of thread specifications? For example, NPT threads come in sizes of 1/8, 1/4, 1/2 (there’s no such thing as 1/3 NPT thread, right?), and what are the common sizes for other types of threads?
You can do this by checking the taper of the thread, whether it is 55° or 60°, as well as looking at the pitch of the teeth. Secondly, 1 inch equals 25.4 mm, and there is an octal system between inches and inches. What is commonly referred to as DN20, or 6-inch pipe, actually means 6/8 inch; 0.75*25.4≈20, so DN20 is sometimes also written as NPT3/4. As a result, there is no such thing as 1/3. Please feel free to share any differing opinions
The threads commonly used for instruments are 1/2’, 3/4’, and 1’ for piping; the pressure gauge connections are G1/2’ and M20*1.5, while the electrical connections are G1/2, G3/4, and M20*1.5. The transmitters come in 1/2NPT and 1/4NPT versions. These are the most commonly used types. If no special requirements are specified when placing an order, these are generally the ones that will be used.
Take a look at the manufacturer’s samples to see how metric and imperial threads are distinguished; generally, sealing joints use NPT or RC threads, which are both tapered threads. G threads are not typically used for sealing joints and are usually employed for connecting pipes