Tip Clearance and Gap Measurement
(ROTATIP, AUTOCAP, ROTACAP and CAPLONG)
All of our tip measurement systems are used for measuring
tip clearance gaps between compressor and turbine blade
tips and the engine inner casing.
ROTACAP and CAPLONG probes will also measure blade disc movement and shaft oscillations when installed at three or more equi-spaced locations. The blades, discs or shafts must preferably be earthed for the systems to operate and a good quality, dry, cooling air and a tachometer signal of shaft speed must also be provided for all systems.
ROTATIP and AUTOCAP are gap measuring capacitive
systems using a retracting touch electrode.
ROTATIP measures the longest blade whilst AUTOCAP,
ROTACAP and CAPLONG measure all blade lengths on an
engine stage.
All our tip clearance and gap measurement systems are, where necessary, calibrated before despatch and can also be supplied with our control and display software RCAP if this is needed.
Rotadata supplies four systems for use in blade tip clearance and gap measurement all used for measurement whilst the engine is running. The probes are located strategically on stator parts of the engine with the probe tip facing the blade tip, disc or shaft surface.
(1) RotaTip : Measures the longest blade (smallest gap) on and engine using a near to approaching actuator driven electrode built into the measurement probe.
(2) AutoCap : Measures all blade lengths and gaps on an engine using an actuator driven near to approaching electrode and a capacitance electrode both built into the same measurement probe.
(3) RotaCap : Measures all blade lengths and gaps on an engine using a capacitance electrode built into the measurement probe. The RotaCap probe cable is short having a maximum preferred material insulated (MI) cable length of 500 mm making it suitable for use on small diameter engines.
(4) CapLong : Measures all blade lengths and gaps on an engine using a capacitance electrode built into the measurement probe. The CapLong probe cable is extended having a material insulated (MI) cable length of up to 2.50 metres making it suitable for use on large or small diameter engines.
All our four types of tip clearance and gap measurement systems are used on many civil and military aero engines, large industrial gas turbines and compressors and on engine development test rigs. Other applications include the measurement of rotating shaft oscillations and blade and stator alignment.
All four types of tip clearance and gap measurement system controllers can be interfaced to our RCAP software and using a PC or laptop enable the display of gaps measured, blade lengths and disc and shaft oscillations. Tip clearance and gap data acquired can be streamed directly to customers own data acquisition system or to the RCAP ground station. We have standard probe designs, of various lengths, suitable for use up to operating temperatures of 1,300°C and, where necessary, the probes are calibrated in our factory before despatch enabling immediate installation and use on the engine.
Rotadata can provide a design service for producing all the appropriate drawings for installing the measurement probes onto the engine.
Blade Tip Grind Measurement System (ROTAGAGE)
The ROTAGAGE rotor inspection system is used for measuring individual rotor blade tip radii on the production rotors of gas turbine engines and compressors during the blade tip grinding process. Click here for more information on RotaGage.
