GUIDE

1/4 thread for pressure transmitters

The 1/4 thread is one of the most commonly used thread types. In the following entry, you will learn about its width and pitch, and which JUMO pressure transmitters it is used in. Furthermore, you will learn about topics such as thread designation and thread types.

What is a thread?

Threads are connecting elements used in mechanical engineering. They are helical cuts on a cylindrical surface. They come in a large number of variants, depending on size, shape, inclination or position, among other things.

Table of inch threads
Thread Number of coils per inch
1/8″ 28
1/4″ 19
3/8″ 19
1/2″ 14
5/8″ 14
3/4″ 14
7/8″ 14
1″ 11
1 1/8″ 11
1 1/4″ 11
1 3/8″ 11
1 1/2″ 11
1 3/4″ 11
2″ 11
2 1/4″ 11
2 1/2″ 11
2 3/4″ 11
Table of inch threads
Thread Stroke [mm
1/8″ 8.848
1/4″ 11.89
3/8″ 15.395
1/2″ 19.172
5/8″ 21.128
3/4″ 24.658
7/8″ 28.418
1″ 30.931
1 1/8″ 35.579
1 1/4″ 39.592
1 3/8″ 42.005
1 1/2″ 45.485
1 3/4″ 51.428
2″ 57.296
2 1/4″ 63.392
2 1/2″ 72.866
2 3/4″ 79.216
3″ 85.566
3 1/4″ 91.662
3 1/2″ 98.012
3 3/4″ 104.362
4″ 110.712

Threads - types

There are many types of threads In the following overview we present the most commonly used thread forms.

In terms of the system of measurements are two types:

  • G threads (inch) - pipe thread, thread angle is 55 or 60 degrees, and thread pitch is the number of turns per inch

  • M (metric) threads - the thread angle is 60 degrees and the thread pitch is given in millimetres.

In terms of position:

  • male thread - positioned on the outside

  • female thread - positioned inside the hole

In terms of pitch:

  • cylindrical thread - formed on the surface of a cylinder

  • tapered threads - formed on the surface of a cone

In terms of pitch:

  • fin thread - smaller thread pitch

  • coarse thread

  • normal thread

Thread form in terms of country:

  • bsp threads (british standard pipe) – Great British standard, for example pipe threads where pressure-tight joints are made on the threads

  • npt threads (national pipe straight threads) – American standard


Can bsp and npt be used together?

These thread types are misaligned, which can result in threads that are only partially fastened. Although 1/2 and 3/4 NPT and BSP sizes have the same pitch, there are differences in thread forms and thread angles, causing connection problems.

Most commonly used threads

In Poland and other countries that use the metric system, the most popular threads are integer multiples of millimetres, such as:

  • Thread G1/2

  • Thread G1/4

  • Thread G1/8

What size is a 1/4 thread?

A 1/4 thread is 6.35mm with a pitch of 28.


Thread roughness

Threads can have different roughnesses. This parameter is of particular importance This parameter is of particular importance when the application requires the medium to be cleaner and not medium is not deposited on the thread. In such cases it is advisable to use a thread with low roughness. In order to reduce this as far as possible, the thread is polished by electrolytic polishing.

Threads for pressure transmitters

For JUMO pressure transmitters, the process connections are different thread types, tailored to the customer's application.

JUMO MIDAS C08 pressure transmitter

The innovative design of the specially developed ceramic sensor ensures an excellent long-term stability of < 0.2 %. It can be used to record relative pressures from 1.6 bar to 60 bar in gaseous or liquid media.

Applications:

  • compressors

  • machine and plant construction

  • industrial pneumatics

  • commercial vehicles

  • construction technology

Process connection

  • 502 G 1/4 DIN EN 837

  • 504 G 1/2 DIN EN 837

  • 511 1/4-18NPT DIN EN 837

  • G 1/4 DIN 3852-11

  • 7/16-20UNF

JUMO MIDAS C08 pressure transmitter

Pressure transmitter JUMO MIDAS S05

JUMO MIDAS S05 pressure transmitters are available for measurement of relative and absolute pressure. Due to the fully welded measuring system made of acid-resistant steel, the device can be used in almost all media, even very aggressive ones.

Application:

  • HVAC (Heating, Ventilating and Air Conditioning)

  • refrigeration technology

  • compressor construction

  • machine building and process automation

  • packaging industry

Process connection

  • 501 G1/8 acc. to DIN EN 837

  • 502 G1/4 acc. to DIN EN 837

  • 504 G1/2 acc. to DIN EN 837

  • 511 1/4-18 NPT according to DIN EN 837

  • 521 G1/4 acc. to DIN 3852 T11

  • 562 7/1620 UNF

  • 563 7/16 - 20 UNF ext. with pressure coupling

  • 621 - small flange DN 16 DIN28403

JUMO MIDAS S05 pressure transmitter - thread

JUMO MIDAS S05 pressure transmitter

JUMO MIDAS S05 pressure transmitter

JUMO MIDAS S05 pressure transmitter

JUMO pressure transmitter dTRANS p30

Threaded connections with integral choke

Some pressure transmitters, such as MIDAS C08, MIDAS S05, MIDAS S06, dTRANS p30, DELOS SI, dTRANS p20 have threaded connections with a built-in choke, which helps to mitigate pressure shocks to the transmitter's measurement system. It is worth using such a solution when the transmitter is located near e.g. a diaphragm pump, where it is exposed to sudden, temporary pressure increases.

Contact us! We will help you choose a device with a thread adapted to your application.


Threads of the JUMO MIDAS C08 pressure transmitter