Drupal Search Api Custom Search Example

search-api-example.php

<?php

$server = search_api_server_load('acquia_search_solr_server');  
$index = search_api_index_load('node_index');

$query = new SearchApiQuery($index);
$query->condition('type', 'article');

$results = $query->execute();

dpm($results);

It works, notes that field type (conten type) must be checked index