We blew the water out of the irrigation lines yesterday. This is to prevent the water in the lines from freezing and cracking the pipe. In order to do this, we rent an air compressor from a large equipment rental company in Detroit. About a dozen golf courses around Ann Arbor go in on this compressor together in order to cut down on costs. We rent it for 3 weeks and shuttle it from one course to the next until everybody is done with it. You may have seen lawn care companies around town blowing out home lawn irrigation systems. They will usually use a 175 cubic foot per minute (ft3/min) air compressor. The one that we get is 825 ft3/min. The pressure that we run is around 60-70 psi. This contrasts with the normal water pressure of between 108 and 118 psi. Anything higher that 75 psi with air and the irrigation heads are at risk of breaking. Here is a picture of the compressor set up in front of the pumphouse.
Here you can see the 2 inch hose running directly into the 10 inch steel line coming out of the pumphouse.
This is the view of the pump controller.
Our two 50 horsepower, variable speed, vertical turbine pumps.
When blowing the water out, the goal is to get 90 percent of the water out. In theory, as long as 70% is out of the line, the pipe should be able to withstand water freezing. The problem is that with the pipe changing in elevation, some low areas might have 2 or 3 times the water that high spots do.
When you first turn on the irrigation head, you get out pure water.
After a few minutes, most of the water is gone.
When you have a large volume compressor, you can have up to 20 heads running at any one time.
Here is a video of the process on #5 green. I apologize for the shakiness.
I borrowed a dump truck from NAP to take the compressor to Tim Dark, Superintendent at Barton Hills Country Club.