Flow control device and trim cartridge assembly for a flow control device

A unitary trim cartridge assembly for a flow control device, the trim cartridge assembly comprising:

• a cage including an exterior groove formed on an exterior surface of the cage;
• a bonnet coupled to the cage and including an overlapping portion and an interior groove formed on an interior surface of the bonnet and on the overlapping portion;
• and
• a retaining element disposed between the cage and the bonnet and extending into the interior groove of the bonnet and the exterior groove of the cage;
• wherein
• a height of the interior groove in the bonnet and/or a height of the exterior groove in the cage is greater than a height of the retaining element to allow the cage to move longitudinally within the bonnet with the bonnet and cage assembled.

A method of assembling a flow control device, comprising the steps of:

• assembling a unitary trim cartridge assembly by:
• installing a retaining element into an exterior groove of a cage;
• inserting the cage into an overlapping portion of a bonnet until the retaining element extends into an interior groove formed in the overlapping portion of the bonnet, wherein a height of the interior groove in the bonnet and/or a height of the exterior groove of the cage is greater than a height of the retaining element to allow the cage to move longitudinally within the bonnet with the bonnet and cage assembled;
• inserting the trim cartridge assembly into a valve body;
• and
• securing the trim cartridge assembly to the valve body.