How do I shutoff or block sewer line while replacing the shutoff valve?

I recently had to replace my sewage pump. The PO put in a PVC ball valve to shut off the sewage when pump repairs are needed. The PVC valve would not move and I broke the turn handle while trying. ....Why anybody puts PVC valve underground and expects it to work after a week or 2 is a subject for another thread... Luckily I did manage to replace the pump without shutting off the valve as there was a check valve before the pump which held stuff back. I would like to replace the PVC ball valve with a brass gate valve. It's about 75 to 100' of 2" PVC pipe to the street with about 12-18" rise. The valve located near the pump. I am not sure if its just the gravity fed contents of the pipe or if I will continuously get stuff under pressure from the main sewer line as well? How can I block the line while cutting out the bad valve and gluing a fitting for the new valve? I was thinking of some kind of balloon or air bladder if such a thing exists for that purpose? Thanks Kevin
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Your sewer lateral is only 2" and rises to the street sewer main? Sounds like a real bad installation. In this area the sewer lateral is required to be 5" in diameter minimum and to drain DOWN to the sewer main, which is about 15 feet below the street.

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EXT wrote:

That's fine for a relatively flat city, but in hilly parts of the country where there are central sewers it is quite common for folks on the downhill side of the street to have tanks and pumps to pump the sewage up to the sewer main. Since the pumps are grinder types, 2" lines are just fine.

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Pete C. wrote:

I am on the end of a 'flag lot' (where 3 homes share 1 driveway). There is an abrupt grade for 10' or so from the street then a gradual slope the rest of the driveway. The first 2 homes did not need a pump but the PO who was also the GC said the sewer lines from my home are about a foot too low. When looking for sewage pumps I found most all are 2" discharge. One or two had a 3" option.
Kevin

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Kevin Ricks wrote:

http://www.cherneind.com/products-display.asp?pind=pp_1
The rubber bladder makes a very tight seal when pressurized.
Go to their product menu for other devices.
A bit tricky to do what you want. I guess you would need to pressurize the bladder, pinch the inlet hose shut, disconnect hose, slide the old valve (which has been cut) over the inlet hose and then slide the new fittings in.
You don't need water to pressurize; compressed air will work fine.
Jim
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Speedy Jim wrote:

Thanks I will look into those if not too expensive.
I may try and use a bicycle inner tube. Or maybe something biodegradable like a couple rolls of TP? I may wait till spring when I can pump a bunch of irrigation water through the pipe to clean it out a bit before starting.
Kevin
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