Network congestion at about 22 minute intervals. Cause?

We have a network segment that every 22 minutes approximately gets very congested for about 10 seconds or so, causing various apps to get disconnected.  We have a multiple vlan environment and only one vlan is affected.  We believe it is being flooded with UDP packets.  The switches  are Cisco with all ports running 100 or gigabit speeds.  We have about 4 servers, about 40 PC's, 7 or 8 printers, and three copiers on that segment.  We usually see the issue on our network by an app that displays on a large monitor that is running on one of the PC's.  The app connects to the internet and displays real-time information.  What happens is there is a notification that the  app has lost it's connection to the internet server.  Other apps are affected at the same time.  We have verified that other lan segments are not affected and the Internet connection for the affected vlan is on another segment.  We need to know how to trace the source of the information.  We have removed the servers and a number of the workstations for a period of time with no change in the issue.

Thanks,
Bobby