Backup a database using c#, the bak file gets bigger and bigger, how do I stop it from growing?

So the scenario is that It seems to append to the bak file when creatin开发者_C百科g it, is it possible to stop it from doing that and just backup the current version?

here is my code

Server backFromServer = new Server(@"server ip add");
backFromServer.ConnectionContext.LoginSecure = false;
backFromServer.ConnectionContext.Login = "uname";
backFromServer.ConnectionContext.Password = "psd";
Database backFromDb = new Database();
backFromDb = backFromServer.Databases["dbname"];

Backup bkpDatabase = new Backup();
bkpDatabase.Action = BackupActionType.Database;
bkpDatabase.Database = backFromDb.Name;
bkpDatabase.Incremental = false;
bkpDatabase.LogTruncation = BackupTruncateLogType.Truncate;                

BackupDeviceItem bkpDevice = new BackupDeviceItem(@"D:\backupfolder\backup.bak",
                                                  DeviceType.File);

bkpDatabase.Devices.Add(bkpDevice);
bkpDatabase.SqlBackup(backFromServer);

Set Backup.Initialize to true:

"If True, the backup specified becomes the first backup set on the media, overwriting any existing backup sets on the media. "