In the drilling industry, elevators are hinged devices used to lift and lower piping, casing and tubes. Their use is essential, as any maintenance issues can bring drilling to a halt. Therefore, it’s necessary to understand the differences between types of elevators and when their use is appropriate. Below, we’ve provided an overview of the 6 differences between G and Y series elevators.
1. Purpose
Y series elevators are a kind of slip type elevator. Slips are used to grip and hold the drill string to the drill floor. Y series elevators are used for hoisting tools and handling tubing, drill pipe and small casing when the appropriate sized slip and setting ring are installed. They serve to avoid gauge damage and bottlenecking.
G series elevators are a kind of center latch elevator. They have an 18 degree taper shoulder, and are used for handling drilling pipe and tools. Due to their design, only tubes with an 18 degree external upset should be used.
2. Tonnage / Capacity
G series elevators have a higher ton capacity, with some models reaching up to 700 tons. Y series elevators typically have a maximum capacity of around 200 tons.
3. Daily Maintenance
Both G and Y series elevators require similar daily maintenance checks. These include applying grease, testing the opening and closing ability of the elevator, inspecting the contact surface of the ears, and checking for damages and cracks. Y series elevators also require a testing of the slip springs by pressing down on them to make sure they pop up, and should also be checked for missing teeth.
4. Semi-Annual and Annual Maintenance
Twice a year, both G and Y series elevators have their latches tested. This is done by trying to manually pry open the elevator. If this is successful, the elevators should be replaced. Magnetic Particle Inspection (MPI) should also be performed. For G series elevators, the taper dimension should be verified. For Y series elevators, pins and springs should be checked for corrosion.
Annual maintenance for both series elevators are the same. They include conduction performance load tests, conducting an MPI test the following day, and checking the casts, repairing if necessary.
5. Elevator Wear
As mentioned above, the G series elevator can be affected by the wear of the bore. Specifically, the taper can round off and provide less contact area to support the tubular. It’s important to measure the angle of the taper in multiple areas, as the taper doesn’t wear evenly.
Both types of elevators should have their ear radius checked as well, as the wear on this can affect the load the elevator can support. If the radius is below the minimum as specified by the manufacturer, the elevators should be scrapped or remanufactured.
6. Troubleshooting
The G and Y series have a lot in common when it comes to troubleshooting. Both can suffer from deformed pin holes and bent pins, resulting from overload and wear. Elevators not opening properly can be a result of corrosion, while doors not closing can be a result of an oversized tubular.However, Y series elevators also suffer from their slips not moving freely. This can result from an incorrect spring or slip bolt, a bind in the setting plate, or an issue with installation. During installation, slip springs may pop out and need to be re-inserted into their cavity. Long screwdrivers are also used to temporarily hold a slip in place before reinstalling the bolt assembly, and can result in a non-moving slip if the reinstallation is not completed properly.