Latches are available in a wide range of designs for use with retrievable gas lift and circulation valves to be installed in side pocket mandrels. These latches are designed to be installed with a minimum of force, a feature very important in deviated wells where forceful downward jarring may be difficult. Side pocket mandrels feature two types of pocket latch profiles: the G-type which has a 180-degree eccentric latch ring profile with the no-go surface located near the lower end of the latch; and the A-type which has a 360 degree latch profile with the no-go surface above the locking mechanism, Latches used in each of these profiles are not interchangeable; however, valves and other flow control devices can be adapted from one profile to the other by selecting the correct latch.
1½ inch TG and 1 inch M Latches are designed for installation in G-type pocket mandrels. A set of collet type locking dogs are free to move up and into a recess in the locking mandrel as the latch engages the pocket profile. When an upward pull is exerted on the latch, the full diameter of the locking mandrel moves behind the dogs which locks them in the set position. To retrieve the valve and latch, an upward force is applied, which shears a pin. This action moves the locking the mandrel up, which frees the dogs to retract as the valve and latch are pulled.
1½ inch T2 Latches are designed for installation in A-type pocket mandrels. They utilize a set of collet type locking dogs configured inside a slotted sleeve. As the latch enters the pocket, the dogs move up and into a recess the locking mandrel. After reaching the no-go position, an upward pull causes the dogs to move over the locking mandrel and lock into the pocket recess. To release the locking dogs, an upward force is applied which shears a pin, moving the locking mandrel up. The latch and valve are then free to be retrieved.