About Your Air Compressor…
September 1, 2008
I recently had the opportunity to speak with Clint Welch, a prominent member of the sales team at America West Drilling Supply, and the conversation quickly turned to air compressors. America West is headquartered in Sparks, Nev., and has earned a reputation as a leading producer and supplier of cutting-edge drilling equipment, so I wanted to get Welch’s take on some of the issues drilling contractors face with their air compressors.
Purchase DecisionWhen it comes time to select the right air compressor for the job, Welch begins with the basics: “It’s important to know what kind of tooling is required because there are low-pressure and high-pressure units,” he explains. “Too much pressure can damage a driller’s equipment. It could even cause the compressor to seize up if there’s a pressure backup. For example, you’ve got contractors doing sandblasting or perforating or cleaning out holes for geothermal plants, and then you have the drilling applications. We strive to match up the contractors’ needs with the proper equipment.
“High-pressure units would be 1,250/435, for example. If you’re running a big hammer – say maybe a 12-inch hammer – and there’s a big annular space, and you need to be sure you have plenty of air to blow out those cuttings, you’d need the higher-pressure unit. But on different applications – if you’re just running tooling or a perforator or sandblasting, and you only need 100 pounds of pressure – we have units that would be better suited for those applications. If you have too much pressure, there’s a safety issue with regard to your system’s hosing.” (It’s a scientific fact that the likelihood of a blown hose is inversely proportional to the distance from that hose of the nearest human body part.)
“If you’re under-pressurized,” Welch continues, “it’s either going to take a longer time to get the job done, or it might not even be able to handle the equipment you’re using. If you’re running a 12-inch hammer, and you don’t have enough pressure to blow out those cuttings, you’re not going to get the productivity you need from the hammer.”
Asked about bailing velocity, Welch explains, “Three thousand feet per minute generally is considered suitable. Our Web site (www.america-westdrillingsupply.com) features an air velocity chart that’s based on the hole’s outside diameter, the drill rod being used and how much CFM is being used. So, if you have a 10-inch hole, and you’re going down 300 feet with 4-inch rod, you can check to determine how much air you’ll need to be successful. In some applications, a driller might have to tag up two compressors to get the job done. Say, for example, someone needs 2,000 pounds of CFM; they might have a 1,250 unit with a 750 unit. But remember, the PSI always reverts to the lower number, so if you have a 1,250/450 unit and a 750/250 unit, you can combine the CFM numbers, but the PSI always is only the lower number. So, in this example, you’d have 2,000 cfm and 250 psi.”
Operational TipsMaintenance is a real big issue when it comes to compressors. Welch says that the compressors American West sells typically come with a maintenance kit – kits, really. “There’s a 50-hour kit, a 500-hour kit and a 1,000-hour kit. It’s very simplified, so even if you’re out in the field somewhere remote, you can get the fluids changed and the filters changed, and maximize the unit’s longevity. As for troubleshooting, there’s an instrument panel that’s electronically controlled that self-troubleshoots. All you do is go to the back of the unit and press F1, and it will let you know about leakage here or low oil there – it’s very specific as to what the issue is, and eliminates any of the guesswork. It immediately lets you know where any problem might be. When you’re busy, you don’t want to be trying to pull things apart, and asking, ‘Where do we go from here?’ And serviceability is made easy because of the accessibility of the panels and service valves. That makes a big difference; there’s no need to be climbing around the unit. A lot of the guesswork has been taken out of the serviceability issues by making it easy to identify any problem, and then allowing for easy access to address it.”
I asked Welch about some of the common situations that lead to problems that easily could be avoided. “At the back of the compressor, there’s an air inlet valve that needs to be released,” he relates. “A lot of times, it’s pressured up, and someone forgets to release the valve, and that can back things up. A lot of times, when we get the units back – we go through every unit when it’s returned to check out everything – we find that the pressure that builds up in the unit is not being discharged, and that can cause problems. And that’s a fairly common situation.
“Some of the units have pre-start capabilities that allow you to pre-start up to three times a day. It’s a nice option. If you’ve got a crew coming in at 5 or 6 in the morning, you can pre-start the unit, and have it running half an hour early to get it up to a nice level before they begin work.”
In general, Welch advises, “If you follow the maintenance guidelines, everything should work just fine, and you’ll avoid many of the common troubles.”
Other ConcernsA few of the other things touched on by Welch:
- “Safety-wise, leveling is important. You don’t want to be
too close to an edge or an area where there might be traffic. Each situation is
different, and you just need to use common sense.”
- “If you’re working in cold weather, you can pre-heat the unit and
use oversized batteries.”
- “Use sleeves instead of whip checks on the hoses. On the
high-pressure units, it seems that a lot of people are using whip checks, and
they’re not truly rated to handle the PSI of some of the machines out there.
The sleeves protect a larger area of the hose instead of just clamping on a
- “Most drilling conditions do not require the compressor to run at
full capacity; you might run at 70 percent or 75 percent. One option available
is a system that regulates your engine speed and air inlet to maximize your
fuel consumption. So if you’re running at 75 percent, you’re probably saving 15
percent on your fuel. And with the price of fuel these days, that can make a
- “Look at transportability. Some units – especially the older ones – are really big and heavy. You want to be able to get to remote areas; you want easy serviceability and you want fuel efficiency. These are critical things to be looking at.”