If we look at the DNA of the people from EPC world, we will find there are two types. There are people who love drawings, schedules and networks and there are others who love their hard hats and safety shoes.
Experience from both the worlds gives a unique 360-degree perspective to imagine the proverbial elephant even when you are looking only at its tail. In either world, what matters most is a “Touch and Feel” of the project. As we learn more and understand more about something we become confident and comfortable about the subject - all because we acquire a touch and feel of the subject. But life is complicated and unpredictable and will always surprise us. That is when we put the sum total of your life long experiences together and take decisions to solve problems. Other people may call it risky but life has put you in that situation and the rest of the world is waiting for your decision. You can take a gamble and win a jackpot or watch the opportunity pass by to repent later. If you take the gamble and win, you learn and if the gamble did not work you learn even more – for the next time. Here is how I learned risk taking from my boss.
For all of us, our first boss is a very important person in our lives. He comes in to our lives at a very important time and molds our career and to a good extent sets the the perspective to how we approach job everyday for the rest of our working life. Mr. Wadia was my first boss at Tata Power at Trombay, Mumbai. A tall stocky balding Parsi man in his late fifties, Mr.Wadia was THE engineer at Tata Power. He appeared always happy because he never seemed worried. The engineer inside him was always visible even under the most difficult conditions. Everyone loved him for his trademark open door and welcome smile. But what most pleased him was when you say “you did not understand what the problem was”. That is when he will make all the efforts in the world to explain the most difficult engineering concepts in as simple words as possible, bringing out brilliant examples from his experiences.
At Tata Power, Trombay Unit 4, Boiler Feed Pumps were of Worthington make. These high speed pumps were of 9000 RPM (revolutions per minutes) speed and overhauling of these pumps was great learning experience for any mechanical engineer responsible for maintenance. Early in my career as a fresh mechanical Engineer in Maintenance department, I had the opportunity to work on the overhaul of one of these pumps.
This was a shrunk fit pump, meaning the impellers were interference fit on the shaft. When two items are interference fit on to each other, thermal expansion plays the important trick. Under dissembled condition, when the shaft and the impellers are at same room temperature, the shaft diameter is a little larger than the inner diameter of the impeller. If you try to slip the impeller on to the shaft, it will just not work. But at a higher temperature the impeller will expand and its inner diameter will increase. Similarly, at a lower temperature the shaft diameter will decrease. Now the shaft and the impeller will accommodate each other. In other words, they will not interfere with each other. That is why mechanical engineers call this an interference fit. On a design drawing it will look like this.This means, every time this four stage pump was to be dissembled or assembled, its shaft has to be cooled by dry ice and the impellers were heated by gas welding torches to make them free of each other. For assembling, again the impellers are heated to expand to the required size and slipped on to the right position on the shaft. There at those final positions, the impellers will cool down and shrink in diameter and the shaft will warm up and expand its diameter. Thus the impeller and the shaft will remain locked to each other without a lock and key arrangement as is normally required for many shaft mounted high speed rotating elements. This makes the locking arrangement precise and solid - to work reliably work at high speeds like 9000 rpm which is 150 revolutions every second.
Considering the skill required to do the job, there was a selected group of technicians earmarked who were trusted with the task of handling this task. The process involved precise measurement of predefined expansion of impellers and then mounting the hot impeller on the cold shaft, before the impellers cooled down or the shaft gets back to normal room temperature. After mounting each impeller on shaft, run out of the assembled unit was measured. Run out measurement of the impellers on the shaft is a method that ensures that the impeller discs are mounted on a plane perpendicular to the shaft centerline. This process was repeated after installing each impeller. After all the four impellers are mounted with acceptable runout, the assembled rotor with all the impellers mounted is sent for dynamic balancing. After receipt from dynamic balancing these impellers were again dismantled by another cycle of impeller heating and shaft cooling and then the pump is again assembled, this time with its stationary parts mounted in between the impellers. The stationary guides in between impellers are used in multistage pumps for guiding the fluid from a low pressure stage to a higher pressure stage.
After completion of all the tasks involved in the overhaul, the pump cartridge was finally assembled and inserted in its barrel casing, centered and aligned. The design of this pump was so precise that the acceptable interference, clearance, centering and alignment tolerances were in the range of one thousandth of an inch. The width of human hair falls in this range.
I have some interesting observations during many project experience. One of these is that important mile stone activates at project sites eventually spill over to late evenings when the energy levels are at the lowest. On one such late evening, before coupling this pump, the lube oil system was started and was kept running for some time to see everything was fine. One of our technicians was instructed to start manual rotation of the pump. The pump rotor was freely rotating without much of problem. But the fitment of the rotor must have made the manual hand rotation of the pump rotor a little hard for the technician who became tired and requested another technician to take over the task. During the transition, the rotor must have briefly come to a standstill before the next technician took over. Panic took over the entire group when the second technician could not restart the rotation. I had a shock of my life, when he said, “Sir - ye pump nahi ghoom raha hai” (“Sir - this pump wont rotate”). We tried for some time with all our energy, but did not apply more force trying to rotate the pump. We thought we might damage something in the pump if we do that.
We all sat down trying to think – what next? But we could not imagine anything new. We were physically tired but mentally getting prepared to restart working to dismantle the pump again. However, wisdom prevailed on us, and we called up our Maintenance Head Mr. P.R.Wadia and told him about the status of the pump and how it got jammed during manual operation. I looked at my watch before we called his number. It was 11.30 PM. Mr.Wadia promptly took the call and said very coolly, “Couple the pump and give it a kick start”. We all looked at each other. In any case the pump has to be dismantled if there was any fitment or other problems. So why not give it a kick and see if it frees up? We did not do any risk benefit analysis at that point of time. We were just waiting to follow instruction only - like a bunch of robots. So, we coupled the pump to the motor and then took name of God and gave a start command to the motor. Without any observable problems, the pump started and was operating smoothly. Relived and relaxed, we went home and had a peaceful night of sleep. This was 1998.
Fast forward 17 years to 2015. In my assignment as Project Head of Jhabua Power Ltd., one of my engineers working in Boiler called me up one evening. He said, they were supposed to take trial run of ID Fan. Since, this trial run was being conducted after a long gap several months after erection of fan, it was agreed with EPC contractor to manually rotate the fan to see if the fan is free and then start it. Even after lot of effort the fan did not move manually. I knew it was my turn to return the favor and learning. I told him to go ahead and give it a kick start. Although I was confident that there was no problem with the fan, I was eagerly waiting for a return call from Bhupinder. And then Bhupinder called me back and told me that the fan was operating smoothly.
I looked up to the sky and thanked Mr. Wadia.
That is where he lives now.
What a “first boss” he was.