Fabricated Thermowells

 

   •  Wide Range of Materials

     - Stainless Steels

     - Exotic Materials

   •  Choice of Process Connections

     - Flanged

     - Screwed

     - Weld-In

   •  Pipe or Tube

   •  ASME IX Coded Welding

   •  Special Coatings

   •  Non Destructive Testing

 

General Description

Fabricated Pockets are precision components manufactured to the highest standard from pipe, tube and bar, to serve as protective devices for primary sensing elements of all types.

 

A wide range of possible products are available. Conditions of pressure, temperature, velocity and corrosion resistance govern the size, shape and selection of materials to ensure optimum dependability, response time and accuracy.

 

Specification

 

Materials

 

We are experienced in the manufacture of fabricated pockets in a wide range of materials, including 304, 310, 316 and 321 Stainless Steels, 446 Cr-Fe, 6% Mo, Haynes Alloys 214, 230, 556 and HR-160, Carbon Steels, Chromium Steels, Duplex and Super Duplex Stainless Steels, Hastelloy B3, C22, C276 and X, Incoloy 800, 825, Inconel 600 and 625, Monel 400 and Titanium.

 

For recommendations on the use of these materials, please click here

 

Pocket Size

We can fabricate pockets from a wide variety of tube or pipe sizes including 11 mm x 7 mm, ¼” NB, ½” NB, ¾” NB, 1” NB and larger, in a variety of schedules subject to requirements and process conditions.

 

Instrument Connection

 

Instrument connections may be male or female, in API, NPT, BSP or other thread forms.

 

Process Connection

 

Connection to the pipe or vessel may be by means of thread, flange or weld.

 

Threaded

Using standard tapered or parallel pipe threads for simplicity and low cost is popular, generally for low pressure applications.

 

Standard threads are NPT, BSP(Pl), BSP(Tr) and API. The thread size is dependent on the application. Standard sizes range from ½” to 2”.

 

Flanged

All sizes and pressure ratings are available to DIN, BS, ANSI/ASME and JIS or other standards. Flanged connections are now the petrochemical standard for all applications.

 

Weld-In

Weld in pockets are normally used where process pressure and velocities are too great for flanged and threaded, or where long term inexpensive connections are required.

 

Reduced Tip

For applications where a quick response to changes in temperature is required, fabricated pockets may be fitted with a reduced tip. The tip is machined from bar-stock, with a bore suited to the primary element, minimising the amount of free air space around the sensor.

 

Immersion Length

The immersion length should be calculated to ensure that the sensing element has sufficient immersion into the process medium to give accurate measurement. To ensure optimum results and freedom from outside influences, thermowell tip should be located at a point which equates with the lower portion of the centre third of the pipe line.

 

For tanks, the depth of immersion obviously varies considerably but, as a rule of thumb, 300 mm from outer wall will give ideal results.

 

In high velocity applications, wake frequency effects must also be considered.