php PhantomJS不止一次搜索

Question

When I search using PhantomJS for more than once. I have a problem with the software being blocked from Google

$client   = Client::getInstance();
$client->getEngine()->setPath('..\\bin\\phantomjs.exe');
$request  = $client->getMessageFactory()->createRequest('http://www.google.com/search?q='.$keyword, 'GET');  
$response = $client->getMessageFactory()->createResponse();
$client->send($request, $response);          

if($response->getStatus() === 200) {
  //some code
}

I made the process with quickly, a large amount without an interval and after a period was blocked and then you put a variable interval and solved the problem and after a period is blocked so far