Application Case Studies

RTD SENSOR ENSURES COLD STORAGE

Industry: Liquid and Liquified Gas Storage Tank Manufacture
Application: Monitoring of internal temperatures to -200° C in large liquid ammonia, liquid nitrogen, liquid oxygen and liquified natural gas (LNG) storage tanks.

Customer Requirement:

The customer has three tank monitoring options:

• Option 1. The tank is filled with liquid nitrogen to pre-cool the tank structure prior to filling with the final product. This prevents rapid cool-down and possible structural damage. Sensors are installed in the insulation-filled annulus area of the double-walled storage tanks.
  
• Option 2. Sensors are installed in the bottom of the insulation-filled annulus area of the double-walled storage tanks to detect leaks.
  
• Option 3. Some storage tank designs require constant monitoring of the tank liquid.

The customer required an RTD sensor assembly capable of immersion in a cryogenic fluid, with a terminal lug for direct attachment to a 0.25" bolt. Leadwire lengths vary from 119 ft. to 279 ft.

Conax Design Solution:
Conax provided a Type T4 RTD sensor assembly with stainless steel braided leadwire to provide the mechanical strength needed to withstand liquid motion forces inside the storage tank. A 3..50" – long stainless steel barrel encapsulates the RTD element and provides a means to bolt onto a 0.25" stud. The wire is mechanically crimped within the SST barrel with an internal Teflon boot for the cryogenic service. A Conax MHM5-040-B12-T seals the leads exiting the storage tank.

Conax and local sales representatives worked closely with the customer's engineering group to develop sensor designs and specification data sheets.