1. MODIFICATION OF MOTORIZED OPERATED VALVE MOV
JOH-KGN JvW-X1
MODIFICATION OF MOTORIZED OPERATED VALVE MOV
Design, Fabrication and Report by:
Boniface Kipkorir Snr, Eng.
Joseph Odhiambo Okoth Snr, Foreman

2. JOSEPH ODHIAMBO OKOTH Senior Foreman, Instrumentation & Controls – OLKARIA
Joseph has worked with KPLC and later KenGen and has over 30years experience. He has vast experience in fabrication and automation. Key achievements Designed & fabricated, the now famous KenGen Soda-ash conveyor system (2012)
Designed and installed level transmitters Olkaria earning the MD & CEO’s commendation
Designed & implemented the clad branding machine at Olkaria in line with KenGen/ KWS MOU Provisions

3. RECOMMENDATIONS AND CONCLUSION
JOH-KGN JvW-X1
OUTLINE
RECOMMENDATIONS AND CONCLUSION
MOV MODIFICATION
MOV VALVE CHALLENGE
INTRODUCTION

4. INTRODUCTION
Plant outages at Olkaria 1 Additional Unit (1AU) due to Motorized operated valve (MOV) failure have been experienced several times and have proved to be very costly in terms of revenue losses.
This presentation seeks to propose a solution on how to reduce the outage times by modification of the MOV.
The problem normally start when the lining of the valve collapses and hinder the free movement of the valve disc, this in turn shears the studs course of the high torque.
The clearance between the disc and the lining is the main reason as to why the valve malfunctions when for whatever reason the lining happens to expand.
The modification seeks to increase the clearance between the disc and the body without compromising the valve operations by introducing the Half Rings on both sides that will be holding the O-rings seals that ensures full sealing when fully closed.

5. JOH-KGN JvW-X1
INTRODUCTION
The O-Ring will be held in position by a retaining ring that is fastened to the half ring by counter sunk SS screws.
The rest of the valve body remain intact including the flange rubber sealing. Control of this water has been the epicenter of the power plant’s smooth operation.
The big advantage about the design change is that there are two small valve that can be used as prototype and be tested for operation before embarking on the major MOV.
For the first modification on the small valves, the material required stainless steel is available, the only expense needed is for procurement of SS screws and O-ring and movement.

6. MOV VALVE CHALLENGES
The damaged rubber
lining

7. ACTUAL SIZE OF MOV
The damaged rubber seal

8. MOV SEAT MODIFICATION After removing the rubber lining from the hub
RUBBER SEAL
GROOVED RING TO CURRY SEAL
HOLDING SCREW
After fixing the half rings on both sides

9. Rubber seal fix and drill for
the holding screws and counter
sunken for cover.
With SS screws
Exposed.
After the screws have bee covered

10. VALVE PLAN VIEW VALVE CLOSED When closed, the disc is meant to
Press on the rubber seal by 3 mm
and up to 5mm on the big valves.
The space between the valve disc and
the body A looks wide for it was filled by
the original rubber that had run round
the valve. The actual encroachment of the
modification to the original diameter of
the valve flow is by 20mm. 10mm on each
side of the disc which is insignificant.
The main aim is to give the valve disc free
movement. In the course of the
investigation of the valve operation, it was
discovered that the clearance between disc
and the rubber on the body is the one that
brings the jam A

11. VALVE PLAN VIEW VALVE CLOSED Water flow DIRECTION OF CLOSSING
DIRECTION OF OPENING

12. THE FINAL PRODUCT When OPEN When CLOSED
When closed can guarantee 94% sealing

13. RECOMMENDATION AND CONCLUSION
The financial implications of the modification can be worked out. But for starters the cost of one valve is approximately five million, and to repair the rubber only is One million, so there will be a huge savings to the company by going the modification way. The downtime of the machines on the said MOV will be reduced thus increasing revenue.
The other area that the modification should be applied is at the main silencer Olkaria 1. The challenge being faced at the moment on management of venting there will be easily managed by the modification.

14. THE END