FIELD OF THE THE INVENTION
The invention relates to the field of pulverizer. In particular, the invention relates to dynamic torque measurement on pulverizer shaft. More particularly, the invention relates to a device for dynamic torque measurement of pulverizer drive shaft using a telemetry system.
BACKGROUND OF THE INVENTION
Pulverizers are used for the crushing of coal to fine powders, to be used for burning in the boiler or heat generator. The fine coal powder flows to the boiler, driven by air from the primary air fan. Pulverizers are driven by electrical motor through rigid couplings. Due to various mixtures of coal and other ingredients, the torque induces the shear strain which warrants a technique to monitor and analyze the torque on the rotor. It is known that strain gauging is one of the ideal technique for torque measurements, which uses strain gauges and a telemetry system. Torque measurements recordings and analysis is carried out for various conditions in the pulverizer. Subsequently the torque measurements are validated through motor power consumption.

As shorn, in figure 1 the prior art tele antenna fixture is not suitable for testing on pulverizer drive shaft, as the diameter of the shaft is larger.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device for dynamic torque measurement of pulverizer drive shaft in a telemetry system.
Another object of the invention is to propose a device for dynamic torque measurement of pulverizer drive shaft using a telemetry system in which the torque characteristics are obtained for various coal conditions and measurements made based on strain gauges and telemetry which are validated with electrical power consumption data.
A further object of the invention is to propose a device for dynamic torque measurement of pulverizer drive shaft using a telemetry system which prevents frequent failures of gear box couplings by making measurement of torque on planetary gear box input shaft of bowl mill.
SUMMARY OF THE INVENTION
Accordingly, there is provided a device for dynamic torque measurement of pulverizer drive shaft using a telemetry system, the measurement system comprises at least two strain gauges detachably attached to the shaft under measurement, a telemetry transmitter connected to the strain gauges by wires such that the

transmitter acting as a rotating antenna to transmit signals from the stra.n gauges, the device comprising one of a Brass Pickup loop or a Telemetry Antenna or an Stationary tele antenna, to transmit signals from the rotating antenna to a tuning enclosure via the stationary tele antenna, wherein the stationary telemetry antenna is provided with a split type mounting to allow an accurate self-alignment of the antenna by maintaining concentricity with shaft within 1 mm, and wherein a dual radius adapter is assigned to transmitter such that the diameter of the shaft can be fitted inside an yoke, which enables a transmitter designed for 76 mm diameter shaft adaptable on a 110 mm diameter shaft.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The above brief description, as well as further objects, features and advantages, of the present invention can be fully appreciated by reference to the following detailed description. These features of the present invention will become more apparent upon reference to the accompanying drawings, wherein :
Figure 1: 3- D view of PGB Shaft connecting the gear box and Bowl mill.
Figure 2: Strain gauges fixed to shaft rotor.
Figure 3: Fixture for Telemetry antenna.
Figure 4: Dual radius adapter for telemetry transmitter.

Figure 5: Tele stationary antenna
Figure 6: Fixture for tele stationary antenna
Figure 7: Mounting fixture for Telemetry assembly on mid-shaft.
Figure 8: Tele stationary antenna with mounting fixture
Figure 9: Tele stationary antenna without mounting fixture
Figure 10: Kevlar Strap for tele transmitter.
DETAILED DESCRIPTION OF THE INVENTION
For making the Torque measurement, surface area of the pulverizer drive shaft as shown in Figure 1 is prepared by cleaning with emery paper. Further cleaning is done using Acetone and CCI4. Position of strain gauges is suitably marked. Bonding of the strain gauges is done with an adhesive. Gauges are taped to the shaft and pressed on to the surface using a Silicon Rubber and pressurizing with a clamp for three to five minutes. After removing the temporary tape on the gauge, soldering is done on the gauges using a lead wire. Normal lead is used for temporary purpose and high temperature lead is used for permanent purpose

Resoline liquid is used for bonding the lead and for removing excess lead. To remove excess Resoline, a removal liquid is used. Two strain gauges of 1000 Ohms capacity are fixed on the shaft as shown in Figure 2. The wires from the

strain gauges are connected to a Telemetry transmitter which acts as a rotating antenna to transmit signals from gauges.
Following are the components of the Torque Measurement Device using Telemetry system as shown in Figure 7.
1. Brass Pickup loop or Telemetry Antenna,
2. Fixture for mounting of the Tele antenna for self-alignment and concentricity with the drive shaft,
3. Dual radius Adapter,
4. Tele antenna holder,
5. Tele antenna holder bracket,
6. Tele antenna base, and
7. Kevlar strap.

The device is suitable for 4-Channel digital telemetry system intended primarily for making strain gage measurements on rotating shafts. Channel gains can be set individually to accommodate a wide variety of testing needs. This device can be easily adapted for different shaft diameters.
The pickup loop is fabricated from a brass rod and has a diameter corresponding to the shaft onto which the transmitter is mounted. The loop should be radially and axially centered with respect to the location of the transmitter mounting so as to ensure that sufficient power is coupled to operate the transmitter. A short cable connects the termination base of the pickup loop to a Tuning enclosure. A fixture is mounted on the antenna base to transmit signals from the rotating antenna to the tuning enclosure via the tele stationary antenna.
As shown in Figure 7 the tele antenna fixture of prior art causes multiple mismatches with the pulverizer drive shaft which leads to erroneous data during torque measurement.
Hence, a device is provided by the present Inventors to overcome prior art disadvantages.

WE CLAIM :
1. A device for dynamic torque measurement of pulverizer drive shaft using a telemetry system, the telemetry system comprises at least two strain gauges detachably attached to the shaft under measurement, a telemetry transmitter connected to the strain gauges by wires such that the transmitter acting as a rotating antenna to transmit signals from the strain gauges, the device comprising one of a Brass Pickup loop or a Telemetry Antenna or an Stationary tele antenna, to transmit signals from the rotating antenna to a tuning enclosure via the stationary tele antenna, wherein the stationary telemetry antenna is provided with a split type mounting to allow an accurate self-alignment of the antenna by maintaining concentricity with a shaft within 1 mm, and wherein a dual radius adapter is assigned to transmitter such that the diameter of the shaft can be fitted inside a yoke, which enables a transmitter designated for 76 mm diameter shaft adaptable on a 110 mm diameter shaft.
2. The device as claimed in claim 1, comprising a Tele antenna holder, a Tele antenna holder bracket, and a Tele antenna base fitted on to said split type mounting.

3. The device as claimed in claim 1, comprising a strap fitted to the yoke which is fixed to the rotating drive shaft under measurement.