This bit of code, reads a txt file and then outputs the contents of that file into part of the page. I added the string replace line to replace the email address that appears in the text file, mainly because I dont want the email to show up on each page for obvious reasons. However its not replacing the email address, any suggestions?

PHP Code:
function displayLargeDescription($dir)
    {
    

        
$handle fopen($dir $this->large_description_file"r");
        while (!
feof($handle)) {
            
$buffer fgets($handle4096);
            
str_replace("email@email.co.uk"," ",$buffer);
            if (
$buffer == strtoupper($buffer))
                echo 
'<strong>' $buffer "</strong><br />";
            else
                echo 
$buffer '<br />';
        }
        
fclose($handle);    }