The LVDT Linear Position Sensor is a robust sensing device applicable for use in a range of position measurement applications.
Constructed of stainless and with no moving parts, LVDTs are often the best linear feedback technology in terms of reliability and longevity.
When applications require position sensors to operate in extreme environments with high temperatures or pressure, LVDTs can be hermetically sealed or vented. But, which configuration works best in different applications?
For applications where corrosive/pressurized media, high humidity or radiation are present, a hermetically sealed LVDT is recommended to ensure outside media does not enter the windings. This sealing makes sensors impervious to dirt, water, steam, chemicals, and even extreme temperatures that can shorten its life or reliability.
In this configuration, the heavy-duty housing, bore liner and end washers of the LVDT Position Sensor are welded together to form a hermetic seal. Typically, hermetically sealed LVDTs can withstand operating pressures up to 3000 psig. The hermetically sealed construction also lets the core withstand temperatures up to 400°F.
Vented LVDTs
To accommodate extremely high pressures, the sensor case can be vented to equalize pressure inside and outside the LVDT linear position sensor,
Vented versions of LVDT Linear Position Sensors can withstand a combination of high pressure, temperatures, shock and vibration. However, since vent holes exposing the coils inside the housing, any fluid in which the LVDT is encompassed must be electrically non-conducive and chemically benign.
Vented LVDTs can operate in temperature extremes of -65°F to +400°F (-55°C to +200°C) and operating pressures of 35 kpsi. High temperature ratings are achieved using internal materials rated for these temperatures.
Shown is a photo of Macro Sensors miniature LVDT Position Sensor that is vented (pressure balanced) to the pressure of the non-conductive mediums to withstand extremely high pressures of the environment.
Macro Sensors
www.macrosensors.com
Filed Under:Sensor Tips
