TILI Automation

 Gap voltage (VDC) is a direct representation of distance between the probe’s tip and the shaft’s surface. This is the quiescent voltage that needs to be adjusted between the proximitor’s output voltage range limits. Any vibration of the shaft will cause the proximitor’s output voltage to vary in precise step. Vibration Probe Gap Voltage Gap voltage of Bently Nevada vibration probe is usually set at -10V. Reason for setting at -10 volt is as we know, proximitor allows probe to work from -2 volt to -18 volt. So voltage difference of 2 to 10 and 10 to 18 is 8 volt. When setting at -10 volt, probe can equally measures vibration at both sides (I mean when shaft is going away from probe or towards probe). Suppose we adjust probe at -9 volt. Probe can detect vibration? Yes, it can can detect vibration but its one side will be margin of 7 volt and other side margin of 11 volt. At 11 volt margin, probe will detect vibration excellent but at other side,7 volt side, it has limitation, when m...

 The Turbine Supervisory Instrumentation or TSI includes those measurements which monitor the behavior of the rotor train assembly. These include the speed, vibrations, axial position, and differential expansion of the turbo set. What is TSI? Turbine Supervisory Instrumentation system which supervises the turbine with the help of instruments. Turbine Supervisory Instrumentation (TSI) Monitors some important parameters which directly or indirectly are linked & predict the healthiness of the turbine. Turbovisory Parameters Vibration Shaft Vibration Bearing Vibration Turbine Expansion Absolute Expansion [HIP/LP] Differential Expansion [HIP/LP] Axial Shift Speed Measurement Key Phasor In order to achieve the purpose of the said measurement indicators, a tap with the world’s trusted manufacturer for vibration monitoring must be carried out, enter Bently Nevada. Tested by time and experience, the Bently Nevada 3500 rack processes the vibrations, axial positions and differential expan...

 A scary part on-site is when you try to install the Thermowell inside the Nozzle and you realize the Thermowell Outer Diameter (OD) larger than Nozzle Inside Diameter (ID)?. Image Courtesy: Parker This simple thing will lead to great delays since you can’t just insert some other thermowell as they go through W.F.C calculations, material selection, etc. Nobody would want this to happen, so Let’s explore the precautions and recommended practices. What factors are to be evaluated for ensuring the Thermowell gets properly inserted in Nozzle I.D 1. Nozzle Schedule Even 1&1/2 inch pipe won’t have the same I.D all the time. The schedule of the pipe needs to be checked. As it is logical the Higher the schedule (like Std, XS, XXS etc) the smaller the I.D available. Software’s like pipe pro can be used to get dimensions. 2. Cladding on Thermowell Thermowell consumes a lot of material as compared to the diaphragm of transmitters etc. So always it is not a cost-effective option to upgrade...

 Thermowell is provided to protect the temperature sensor from mechanical damage and corrosion. An extremely sturdy design may increase the life of the sensor but may lead to a poor response. Similarly, a delicate design will have poor life but will improve the response time. Therefore, a proper balance needs to be struck. For given process parameters, we can arrive at an optimum Thermowell design considering aspects such as temperature, pressure, fluid velocity and corrosion. Such designs will conform to ASTM PTC 19.3. The Thermowell material can be brass, SS304, SS316, SS316L, SS310, Inconel® 600, Incoloy® 800, Monel®, Hastelloy® depending upon the process parameters and type of fluid. Types of Thermowells Bar Stock Threaded (BT) (Process threads NPT, BSP or Metric) Bar Stock Flanged (BF) (Flanges as per ANSI, BS or DIN ) Bar Stock Weld In (BW) Fabricated Threaded (FT) Fabricated Flanged (FF) Fabricated Weld In (FW) Barstock Thermowell is normally offered up to an insertion lengt...

 Here we discuss the brief overview of different In-House testing methods carried out for RTD assemblies in the Calibration Laboratory. RTD Testing Methods The below list shows the different testing methods. 1. Calibration RTD calibration can be done as per IEC 751 / DIN 43760 Class A & B. Normally test is conducted for two points (i.e. 00 C & 1000 C), 3 point calibration or more can be followed. 2. Insulation Resistance Test at ambient (room temp.) at 500 VDC It should be more than 100 M ohms. 3. Insulation Resistance Test at 3200 C at 100 V DC IR should be more than 2 M ohms. More than 20 M ohms also can be offered. 4. N2 leakage test For the RTD sensor, after cap welding, the N2 leakage test should be carried out no leakage should be observed at 40 kg/cm2. 5. Response time test Response time test as per IEC 751 – (63.2% step change from ambient to 800C). For RTD without transmitter – 6 to 9 sec up to 6 mm OD of sheath. For RTD with thermowell – the response time will be ...

Thermowell as simple as it looks requires a lot of consideration with respect to Wake frequency calculation, material selection, etc. Installing a Thermowell near upstream of a pump is not recommended unless there is a dire need to do so. Thermowell Installation  (Standards like PIP PCSPS001 in section 4.6.5.1 suggest that thermowells shall not be located between suction screens and inlets of pumps, compressors, or turbines) In such cases, it is not mandatory but recommended to install a thermowell on an elbow (A safety margin for below-listed errors) as compared to perpendicular thermowell installation near such critical cases. But every recommendation must have a reason, the following are the factors that empower this elbow installation near pump upstream, etc. The wake frequency calculation as per ASME PTC 19.3 does not cover every case. The analysis of thermowell response to fluid flow in ASME PTC 19.3 presumes a steady fluid velocity. Pulsating flows where the fluid velocity v...

 Here we shall see detailed specifications of Thermowells. Thermowells shall be provided with every temperature element and shall be machined out of bar stock up to length 600mm and with SS 316 material as a minimum. Thermowell Specification The design of thermowell shall be according to standard drawings for flange type up to 600# ANSI. Above 600#, the contractor may use their proven design for a specific application Flange material SS 316 as minimum In corrosive and abrasive services Stallited thermowells are used. There shall be no air gap between the bulb and thermowell to ensure a rapid response. Internal diameter shall be suitable for temperature elements. In very high-pressure applications, the welded type of thermowell is used. The inside diameter of the finished thermowell shall be concentric with all other diameters with a tolerance of 0.2 mm. The thermowell shall be machined and rifle drilled to a smooth finish after welding and heat treatment. The surface finish of the ...

 The thermowell is the industrial housing for temperature elements like RTD or thermocouple or temperature gauges. Thermowell is directly exposed to process fluid/media. Inside the thermowell, element/gauge is installed. Thermowell transfers the heat to the temperature element. Depending upon the element type, the fluid temperature can be known. So Thermowell protects the temperature element against harsh conditions and process fluid. It enables removal of the temperature element for replacement, repair, or testing without affecting the process system. Generally, thermowells are provided with all-temperature Elements like RTD or Thermocouple or temperature gauge. A few exceptions would be bearing RTD, skin type thermocouple, air duct thermometer, etc where thermowell is not applicable / required. When the thermowell assembly is inserted into the pipe, it is subjected to vibration. This vibration is caused by vortices to be generated alternately on either side of the thermowell. The...