Lapping of a control valve

Most of the control valves give sealing by the metal to metal contacts. Due to cavitation, flashing, erosion, or unidentified causes, the gap will be produced between the plug and seating.

seat for lapping

Such a gap or scratches will causes leaking and free movement of a control valve or ON-OFF valves. Lapping is the only way to eliminate such things. Lapping is the process of controlled grinding using lapping paste. Lapping paste is a mixture made of different grades of Carborundum which is generally harder than the silica sand. There are different grades depending on how hard the lapping to be done. The grades are coarse, medium, hard, fine and super fine.

The process of lapping is done by applying a little paste on the seating portion of the plug.

Put the plug and bonnet back.

Connect the handle of lapping set to the stem

Apply slight force and make half rotation in both clockwise and anti clock wise directions

After making 5 to 10 rotations take the plug outside and clean it

Repeat the process until the stem and seat becomes fine without scratches by applying proper grade of lapping paste.

Now a day the lapping is done by using sophisticated lapping machines as shown below

different lapping tech

Parameter setting of  E+H LT

Parameter setting of E&H FMP51 GWR LT

Siemens LT parameter setting

Parameter setting of Siemens Probe LU Ultra sonic Level Transmitter

Parameter setting of KTek LT

Parameter Setting of KTEK MT 5100 GWR LT

Analysis of Pump Vibration

Analysis of motor/pump vibration

HART Communication

HART Communication

Instrumentation tube fittings

https://kishorekaruppaswamy.in/2018/03/28/instrumentation-tube-fittings/

Radar LT non contact type

https://kishorekaruppaswamy.in/2018/03/19/radar-non-contact-level-transmitter-working-and-parameters/

Rosemount GWR parameter setting

https://kishorekaruppaswamy.in/2018/03/15/parameter-setting-of-rosemount-gwr-5300-series-lt/

Offset calculation GWR

https://kishorekaruppaswamy.in/2018/02/14/offset-calculation-for-a-guided-wave-radar-level-transmitter/

Temperature transmitter types

https://kishorekaruppaswamy.in/2018/02/13/temperature-transmitter-classification-tree/

Flow transmitter types

 

https://kishorekaruppaswamy.in/2018/02/13/flow-transmitter-classification-tree/

Level transmitter types

 

https://kishorekaruppaswamy.in/2018/02/13/level-transmitter-classification-tree/

Pressure  transmitter types

 

https://kishorekaruppaswamy.in/2018/02/13/pressure-transmitter-classification-tree/

Piping and Instrument diagram

https://kishorekaruppaswamy.in/2018/02/04/pid/

Smoke detector working

https://kishorekaruppaswamy.in/2018/02/02/smoke-detector-working-principle/

 

Conductivity transmitter working

https://kishorekaruppaswamy.in/2018/02/02/conductivity-transmitters/

Gas detector working

https://kishorekaruppaswamy.in/2018/02/01/gas-detector-working-point-gas-detector/

Flame detector working

https://kishorekaruppaswamy.in/2018/02/01/flame-detector-working-principle/

Units and conversion

https://kishorekaruppaswamy.in/2018/01/05/units-and-its-conversion/

Specific gravity

https://kishorekaruppaswamy.in/2018/01/05/specific-gravity-of-selected-liquidsgases-and-saturated-waterfor-different-temperatures/

Instrumentation Interview questions

https://kishorekaruppaswamy.in/2018/01/03/instrumentation-interview-questions/

Temperature transmitter calibration

https://kishorekaruppaswamy.in/2017/12/20/temperature-transmitter-calibration/

Pressure transmitter calibration

 

https://kishorekaruppaswamy.in/2017/12/19/pressure-transmitter-calibration/

Magnectostrictive LT calibration

https://kishorekaruppaswamy.in/2017/12/19/magnetostrictive-level-transmitter/

Hazardous area classification

https://kishorekaruppaswamy.in/2017/12/17/hazardous-area-classification/

Excel short keys

https://kishorekaruppaswamy.in/2017/12/16/excel-short-keys/

Digital electronics

https://kishorekaruppaswamy.in/2017/12/14/digital-electronics/

Thermocouple mV conversion chart

https://kishorekaruppaswamy.in/2017/12/14/thermocouple-temperature-mv-conversion-chart/

Foundation field bus

https://kishorekaruppaswamy.in/2017/11/20/foundation-fieldbus/

Rosemount 3051 series transmitter

https://kishorekaruppaswamy.in/2017/11/20/rosemount-3051-series-transmitters/

Hydrogen sulphide

https://kishorekaruppaswamy.in/2017/11/20/hydrogen-sulphide-h2s/

Root cause Analysis

https://kishorekaruppaswamy.in/2017/11/20/root-cause-analysis/

Shore Key Line up

https://kishorekaruppaswamy.in/2017/09/28/how-to-line-up-interface-level-transmitter/

pH Analyser

https://kishorekaruppaswamy.in/2017/09/27/ph-analyzer-working-principle-and-calibration/

Mathematic Formula

https://kishorekaruppaswamy.in/2017/09/24/important-mathematical-formulas/

India

https://kishorekaruppaswamy.in/2017/08/15/india/

Oil in Water Analyser

https://kishorekaruppaswamy.in/2017/08/13/oil-in-water-analyzer/

BSW Analyser

https://kishorekaruppaswamy.in/2017/08/13/bsw-analyzer/

Capacitive Level Transmitter

https://kishorekaruppaswamy.in/2017/08/12/capacitance-type-level-transmitter/

LRV and URV Level Transmitter

https://kishorekaruppaswamy.in/2017/08/11/lrv-and-urv-of-interface-level-transmitter/

Instrument Loop Diagram

https://kishorekaruppaswamy.in/2017/07/28/instrument-loop-diagrams/

Laser Level Transmitter

https://kishorekaruppaswamy.in/2017/05/20/laser-level-transmitters/

Turbine Flow Transmitter

https://kishorekaruppaswamy.in/2017/05/20/turbine-flow-meter/

Zero Suppression and Elevation

https://kishorekaruppaswamy.in/2017/05/18/zero-suppression-and-elevation/

Bently Nevada 3500 VMS

https://kishorekaruppaswamy.in/2017/04/08/bently-nevada-3500-vms/

Control Valve Servicing

https://kishorekaruppaswamy.in/2017/04/08/smp-of-a-control-valve/

Safety Integrity Level

https://kishorekaruppaswamy.in/2017/02/23/safety-integrity-level-sil/

Instrumentation Working Principle

https://kishorekaruppaswamy.in/2017/02/22/instrumentation-working-principle-continued/

Instrumentation Gland Sizes

https://kishorekaruppaswamy.in/2017/02/15/instrument-gland-sizes/

LRV and URV of DP level transmitter

https://kishorekaruppaswamy.in/2017/01/02/lrv-and-urv-determination-for-d-p-type-level-transmitter/

Instrumentation working principle continued

https://kishorekaruppaswamy.in/2017/01/02/instrumenation-working-principle/

Level measurement using Pressure gauge

https://kishorekaruppaswamy.in/2016/06/10/level-measurement-using-pressure-gauge/

Tips and tricks in field Instrumentation

https://kishorekaruppaswamy.in/2016/04/18/tips-and-tricks-in-field-instrumentation/

Data Communication Protocol

https://kishorekaruppaswamy.in/2016/03/10/data-communication-protocols/

Pressure Unit Conversion

https://kishorekaruppaswamy.in/2016/02/19/pressure-unit-conversion/

Calibration of  GWR level transmitter

https://kishorekaruppaswamy.in/2016/02/19/calibrationtheory-and-initialization-of-gwr-level-transmitter-rosemount-5300-and-ktek-5100/

Control Valves

https://kishorekaruppaswamy.in/2016/02/18/control-valves/

ERS Level transmitter Parameters

https://kishorekaruppaswamy.in/2016/02/18/calibration-and-initialization-of-electronic-remote-seal-level-transmitter-rosemount-3051ers/

Calibration of wet leg tube Level transmitter

https://kishorekaruppaswamy.in/2016/01/16/calibration-and-initialization-of-wet-leg-impulse-tube-rosemount-3051cd-series-lt/

Calibration of capillary type Level transmitter

https://kishorekaruppaswamy.in/2016/01/15/calibration-and-initialization-of-rosemount-3051cd-capillary-type-level-transmitter/

mV conversion chart

https://kishorekaruppaswamy.in/2015/02/27/942/

Gulf JOB

https://kishorekaruppaswamy.in/2013/09/18/contact-details-for-gulf-jobs/

 

Reynolds Number

https://kishorekaruppaswamy.in/2012/11/28/reynolds-number/

Calibration of displacer type LT

https://kishorekaruppaswamy.in/2012/11/16/calibration-procedure-of-displacer-type-level-transmitter/

My profile

https://kishorekaruppaswamy.in/2012/06/20/click-here-then-photo-and-view-profile/

Chemical hazard pictogram

 

https://kishorekaruppaswamy.in/2012/04/04/chemical-hazard-pictograms/

RTD conversion chart

https://kishorekaruppaswamy.in/2012/02/17/calibration-of-dp-type-transmitter-with-actual-pressure/

Ingress Protection

https://kishorekaruppaswamy.in/2012/01/18/ingress-protection/

 

To know more about Instrumentation and Control,

 

or

 

Basic Instrumentation and Calibration

 

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