By: Ryan Preddy, General Manager & Chris Pudlak, Engineering/Product Manager, DCD Design & Manufacturing Ltd.
Every part of your drill string is under tremendous stress during the drilling process. Small parts are especially important because they’re often overlooked. However, HDD tools like swivels and disconnects must be engineered with strength and durability in mind, or else your operation could pay for it.
In this article, we’ll tell you everything you need to know to make sure you’re choosing the right HDD swivel and using your swivel correctly.
What to look for when choosing your swivel
Also, pay special attention to your swivel’s design features. Here are some things to look for:
- Seals - Your swivel should feature a strong sealing system. The seals keep the drilling fluid, sand, and environmental conditions from getting to the bearings. If any of this reaches the bearings, it’s not long before your swivel is just a shaft. For drilling in harsh environments, consider a multi-stage sealing system.
- Grease pressure protection - The ideal HDD swivel should have internal design features to protect the seals from being damaged by excessive pressure during greasing.
- Safety - Make sure your swivel has a high safety factor rated for HDD. Utilize a swivel at 10 percent above its rated capacity and you will decrease bearing life by 25 percent. Use a swivel at 10 percent below its rated capacity and you will increase bearing life by 40 percent.
As with many HDD tools, you get what you pay for. Look for swivel manufacturers with a long history of designing parts specifically for HDD operations. Use a cheap product from an unknown brand and you run the risk of your swivel failing when you need it most.
How to get the longest life out of your HDD swivel
Once you’ve chosen the perfect swivel, it’s time to get to work. As with any of your HDD tools, to get the longest life out of your investment, you need to keep an eye on it and perform sufficient ongoing maintenance.
Mind the gap
At the end of each pull, preferably before you remove your swivel from the pipe string, continue rotation while spraying it down with a water hose. Make sure you clean out the gap thoroughly because mud tends to accumulate here. When bentonite-infused mud dries out in the gap, it can lock the seal parts together or create abrasion that can lead to cracking.
Grease your swivel thoroughly
A swivel’s main job is to rotate smoothly and this requires plenty of lubrication. Pay close attention to the fact that the grease you add might be flowing out into the gap between the two halves of the swivel. Pump your grease throughout to make sure that you flush out contaminants from deep inside the swivel.
Swivels with a relief valve do not permit the grease to pass the seals. In these cases, make sure that the relief valve is fully open and clear from obstruction as you grease. If grease cannot exit fully through the relief valve, it might mean that your swivel is no longer operational and requires replacement.
Finally, check for grease escaping from the split line groove. If this is the case, it can indicate that the mechanical seal is damaged. Replace your seal before using the swivel on another job.
Here’s a video demonstrating how to properly grease a Valu-Dub swivel. Make sure you’re doing it right.
Rotate the halves of your swivel manually. Its motion should feel smooth and uninterrupted. If you notice an internal grinding sensation, this indicates that the bearings have been compromised. Check the clevis pins for fretting or bending and inspect the clevis lugs around the pins for gouges or any other damage.
If necessary, you can swap out bearings using a replacement kit from the swivel manufacturer. Keep in mind that replacing bearings may require specialized equipment to remove the cap. In these cases, send your swivel to the manufacturer or another authorized repair center for service.
As with all HDD tools, it’s always a good idea to store your swivels indoors, away from moisture and harsh temperature changes. If you have a high-quality swivel designed specifically to stand up to the demands of HDD, then proper storage, proactive maintenance, and frequent inspections should ensure that your swivels remain functional for many years to come.
Questions about the right HDD tooling for your job? Contact the HDD experts at Melfred Borzall today.