Thursday, March 19, 2015

Had To Start With The Big Valve.

   After yet another trip to the Big City, I have returned with the new generator end that arrived from the factory in Texas, along with a few more odds and ends. There had been a list in my head of things over the years concerning the pelton-wheel that I planned to do if it was ever down for any period of time. Little improvements, and maintenance issues here and there, that just needed some time with the water turned off to accomplish. 
The past several weeks broken down like I've been has been a perfect opportunity. Only thing was, I couldn't shut the water off completely. There has been an issue with the main valve leaking, which has been getting progressively worse over the past few seasons, and really makes it difficult to work on. So I ordered a replacement, which I picked up the other day with the generator.

First thing yesterday I tore up the mountain on the Honda, hiked down into the intake pond and dropped the gate valve in the pond, it doesn't seal completely, so I disconnected the penstock a few feet below to keep the dribble of water running down the line and pouring out on my feet while I'm trying to change out the main high-pressure valve located down at the pelton-wheel. The 580 meter (1900 ft) penstock drained out in about a half hour, and I got out the heavy duty socket and ratchet, supporting the pipe on a couple jacks.

 Here be the offending, 6" high-pressure valve. Its a gear actuated butterfly that no matter how fast you crank on the wheel, it closes very slowly so you don't blow something up. 
But as it is, no matter how hard you close it, it doesn't stop the water.
 I got the old valve off, which weighs about 65 lbs., and drug it outside in the light and the problem became obvious. The leading edge of the butterfly was damaged from rocks and gravel coming down the penstock during those bad storms when something washes out above. I recall problems with the valve started after a bad storm about 4 years ago. I thought there was a small stick wedged in there, and it got worse after a few more storms, Then after the Winter storm last December when the road washed out up the mountain I got some more junk down the line which beat up the sealing edge even more. You have to be able to turn off 'all' the water in order to service the machine, and it was a real pain in the ass with this leaky old valve.

The replacement one is not so extravagant, and was about a $1000 cheaper. I didn't figure I needed the gear drive job and went for a simpler lever type, I just have to remember not to turn it off too fast. I went up top and connected the penstock line and pulled up the gate valve in the pond to fill the pipe and came down to check for leaks. 
There is 200 psi of water behind that butterfly valve, you wouldn't want to crack it open to peek in there, it would blow you right out the doorway. That remaining section of pipe needs to be lifted up and held there while the bolts get started, a two man job normally. This particular section has never been off all these years, other than once, about a month ago during the last monsoon washout. Pierre and Cody were camped out enjoying the hot spring and made the mistake of asking if there was anything they could 'help' me with. That was a mistake. I decided that would be a good time to drain the penstock, pull off that heavy bloody section of inlet pipe and dive in there and see if we could fix that leaky main valve. 
The poor buggers kneeled in the water and un-did and did-up bolts and fought with the mis-aligned flanges while I stood around telling stories and handing them tools all day, and I made them work right through lunch break until about 3 or 4 in the afternoon before they finally quit en-mass, and departed for their hot spring holiday once more. Turned out the valve was just had 'er, and I started the search for a replacement. I sure did appreciate their help though.
I should have invited them back. One particular old guy just had to manage by himself today of course, and spent the rest of the day layed out on the couch moaning.
The flanges didn't line up, and it was a heavy, awkward job. Worst part was despite wrecking myself in the process, I never did get the damn thing lined up right.

 So first thing today I gimp over there with my sore back 24 hours smarter with a much better idea, and rigged up an overhead attachment for a come-a-long to support it while I figured out what the problem was. Anyways, without getting too technical, the section between the valve and the pelton-wheel is actually two sections mated together with a clamping high pressure sleeve.  I recalled when I installed all this years ago I didn't leave much gap between the two pipes and I suspected some contact there that made it difficult to line up the flanges.
That turned out to be the problem alright, so I hoisted the short stub up on my shoulder and over to the shop and bucked off 3/4 of an inch with the cutting torch and ground it all down nice like. Being a little smarter than I was a half hour before, I loaded the now shortened flange onto my little wagon, and hauled it back to the pelton-wheel shack on that.
I had to tap out an new gasket for the lower flange, a discarded old drum-head carton works just fine.

It fell into place almost and all 16 big bolts lined up nicely, and that come-a-long was a hell of an improvement. I can't turn the valve on and test for leaks quite yet, theres some more work I need to do on the pelton-wheel.  

Without getting too technical again, this part is called the 'stream deflector'. If all is is not well with the water supply or the electrical system, a solenoid releases a weighted arm that turns the deflector into the stream of high pressure water that runs the pelton-wheel, stopping its propulsion.  It rides on a couple of nylon bearings I installed a season or two ago, but they leaked water like hell all over the floor in there. I got that problem fixed (I hope) with my secret process I'm not ready to divulge here yet. In my fartings around with the stainless steel deflector assembly, I dropped it down into the lower sump with a splash, and spent a good hour with my head and a flashlight stuck in there trying to fish it out with a long hooked rod. 
Well, I think I got all my little down time fixes done I need to. The new generator sits in the back of my pickup, and you are probably wondering why I'm in no big panic to get it installed. Turns out the factory improved that model generator with a larger input shaft than the old one, and the original coupler no fit no more. A new drive coupler flange between the pelton-wheel and the generator was ordered and flown out from Edmonton and put on the Greyhound for Pemberton. I'll pick it up when I go in for a dentist appointment Saturday. (I hope)
So in the meantime, I've had the leisure time to do some much needed repairs and improvements. 
Maybe I'll get around to loosely install the generator later tomorrow. 
But there is one more nasty, awkward, and creepy job to do that I left until last. 
I'll let you know how it goes tomorrow, ...if I'm still here.

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