Instead of a META tag, you could use JavaScript to force a refresh.

In the HEAD section, you have:

<script type="text/javascript">
setTimeout ("oneSec ()", 1000);
var numSecs = 20;
function oneSec () {
numSecs--;
if (numSecs == 0) {
self.location.href = <This URL>;
} else {
setTimeout ("oneSec ()", 1000);
}
}
</script>