Displacement transducers deliver robust and reliable protection

In many demanding industrial condition monitoring applications, there is a need for robust and reliable transducer systems, such as devices like accelerometers, velocity sensors, and proximity probes, which must meet these challenges. As a result of its 50 years of experience in designing and manufacturing essential monitoring sensors and systems, SENSONICS offers specialised condition monitoring products and also the vital engineering and technical capability to deliver custom-designed sensors when required.

Its wide range of LVDT displacement transducers may not always fulfil the specific requirements of some applications, and this is where its established bespoke design services make a significant difference. Whether for a new application, replacing an obsolete product, or your existing supplier cannot meet your needs, the company has the technical expertise to deliver a cost-effective solution. It can guide you through the options within our standard range with customisation for a form fit and function match or develop a new design from scratch.

Taking linear measurements using LVDT displacement transducers on large steam turbines to measure the movement of the turbine pedestals on the cylinder sole plates. This is a relatively easy measurement to make, which needs an LVDT mounted on the turbine and an extension rod fixed or sprung onto the slides. When the turbine reaches its operating temperature, it expands, which can cause one side of the sliders to stick while the other side continues to move. If this occurs, the difference in the displacement output from LVDTs mounted on either side of the machine will increase to the point of creating an alarm in the control room. This is because the turbine is 'crabbing' and, therefore, requires an engineer to be deployed to free the sticking pedestal from its slider plate, ensuring more efficient and effective maintenance.

There are many other applications for LVDTs in addition to addressing thermal expansion issues. For example, the movement of structures, such as bridges, tunnels, buildings and dams, to detect deformation or crack monitoring. LVDTs are also used as valve or actuator position feedback transducer where the signal feedback is sent to the turbine control system so that it knows how far a valve is open or closed. These can be retrofitted onto bracketry across the fixed and moving parts of a steam valve or in conjunction with the OEM as a high-pressure-resistant design internally within the actuator.

The principles of operation of LVDTs allow them to be configured in a variety of housings, depending on the degree of mechanical protection required. The use of rod end bearings, linear rolling element bearings, and flexible conduit helps them withstand the most severe environments. Sensonics also offers signal conditioning units for their LVDTs, which provide oscillator and demodulator functionality. Options include the DN8032 DIN rail mount signal conditioning unit, the DC8042 die-cast enclosure conditioning unit, and the Sentry G3 API 670 standard-compliant ultimate machine protection system.