The files .tx_devvw are transaction files that are delivered to location devvw. The folder in which they appear indicate the location that the transactions were captured from. Every transaction file contains one or more source transactions, but a source transaction is never split across multiple transaction files. HVR generates transaction files frequently to keep latency low.
You can trade latency with somewhat larger transaction files by telling HVR to bundle more changes. You do that by setting an action Environment /Name=HVR_SCAN_DELAY /Value=60 (value is in seconds) on the source location. In that case you get at most one file per minute i.e. at most 1,440 files/day but of course there is extra latency. Of course after you make the configuration change run HVR Initialize with only option Scripts and Jobs checked for the source location to implement this change (and start the capture).
Hope this helps.