A filtering device, a system including the filtering device, and methods of using the filtering device. The filtering device is configured to be arranged inside a fluid to be filtered and comprising at least one main filter and a filter holder supporting the main filter. The filtering device is configured to be moved inside the fluid, in such a way that when the filtering device is moved in a first movement direction, at least one part of the fluid passes through the main filter in a first filtering direction. The filtering device is configured in such a way as to prevent the fluid from passing through the main filter in a second filtering direction opposite to the first filtering direction when the filtering device is moved in a second movement direction opposite to the first movement direction.