Force Main inspection/cleaning
Force Main inspection/cleaning
(OP)
Hello all. Our client has a 10-inch force main that appears to have too much friction for the length of pipe and flows involved. Our calculations show discharge head should be about 5 feet, yet gauge measurements show 22 feet. Flow is about 400 gpm, and the pump is operating on its curve. The pipeline has 45 and 90 degree bends, a gate valve, and a swing check valve before its discharge into another 12-inch diameter force main. I haven't seen the as-built drawings yet, but I'd be surprised if pig launch and recovery are included in the design. Possible suspects we've considered are: (1) faulty air release valve in the pump station (the extra head is suspiciously close to the vertical pipe drop within the pump station), (2) solids accumulation in the pipeline, and (3) construction debris in the pipeline. What options are available for troubleshooting and cleaning this pipeline?





RE: Force Main inspection/cleaning
How long is the pipeline?
The velocity is below the normal self cleaning velocity of 1 metre/second. Can you increase the velocity to achieve self cleaning?
Is there a back pressure from the 12" pressure main causing an increase. i.e. what is the static head?
Can the line be isolated?
Having said that I would check the air valve first, then try increasing flow rate (if the pipe will take the pressure and then look at using a camera (if it will go through the bends).
Other possibilities are A To split the line into 2 lengths and measure pressure in each half to narrow the problem area down and B try a pig if you can load one.
Stephen A
RE: Force Main inspection/cleaning
RE: Force Main inspection/cleaning
RE: Force Main inspection/cleaning