A method is provided for obtaining a product sample from a vacuum vessel by using a system including a first valve arrangement, a second valve arrangement and a sample receiver connected to the first valve arrangement and the second valve arrangement. The method includes opening the first valve arrangement to provide fluid communication between an upper volume of the vacuum vessel and the sample receiver, opening the second valve arrangement to provide fluid communication between a lower volume of the vacuum vessel and the sample receiver, closing the first valve arrangement and the second valve arrangement, opening the first valve arrangement to provide fluid communication between surrounding atmosphere and the sample receiver, and opening the second valve arrangement to collect the product sample.