Hydraulic Valves Make Machines Rock Solid

Hydraulic Valves Make Machines Rock Solid

TEI Rock Drills Inc., Montrose, Colo., has grown to become a leading international manufacturer of drilling attachments for the construction, mining, fencing, and geothermal industries. Although all of the company’s manufacturing is done in its plant in Montrose, TEI is international in scope, with its products shipped to every continent in the world.

TEI’s TE300 is a hydraulic rotary percussion drill designed for use with 10- to 20- ton excavators to drill holes for blasting, grouted anchors, fencing, micropiles, and foundation repair. Its hammer uses 20 gpm at 2000 psi for generating up to 3500 blows/min with 110 ft-lb of energy per blow.

This is impressive growth for a small firm that began in 1980 by providing single-boom underground machines and consulting services for the mining sector. Since then, TEI has concentrated on the continued development of drilling attachments as well as limited access and man-portable drills designed for foundation repair. The company now builds more than 100 drills per year in a 30,000 ft2 manufacturing facility, with a new 6600 ft2 warehouse to store large parts as well as completed attachments.

Valve upgrade needed

The original design of one of TEI’s core machines used basic directional control valves. “We were using a basic valve combination when we started making our drilling attachments,” said Sue Frank, president and CEO of TEI. “Sometimes, when the user touched the handle on the attachments that employed this set-up, all of the flow went to the drill at one time and caused it to move too fast.”

But that wasn’t the only issue that the old valves presented. “With the old valve sections we were using, no matter what you did when you pushed that handle down, that function was draining 20 gpm,” she explained. “Normally, you only have 40 gpm for any machine, so your first two functions are essentially eating up everything that pump can put out. As a result, that third function might not operate quite as well.”

TEI officials realized that the discrete directional control valves were at the core of the problem. So when the company began employing 360° positioning capabilities on the attachments, Frank knew they needed to find a proportional valve controlling flow to the positioner. This would allow the operator to ease the attachment into position, instead of slamming it.

In Search of a Solution

In 2003, TEI executives were attending a trade show with the express goal of identifying a valve supplier that could meet the company’s technical and stringent delivery needs. The ability to meet customers’ delivery times is a critical ingredient for success in the drilling industry. One of TEI’s competitive advantages is its penchant for providing this quick delivery to its customers — typical delivery time for TEI equipment is eight weeks or less. To maintain this reputation for punctuality, its valve supplier would have to be able to deliver just as promptly.

“We started talking with several competitive companies, but even the ones that carried the kind of proportional valves we needed were unable to commit to our delivery schedules,” Frank recalled. “Without both a quality product and timely delivery, we knew we could potentially lose our edge in the marketplace.”

After some additional searching, TEI discovered HAWE Hydraulics, Charlotte, N.C. Convinced that HAWE could supply the ideal proportional valves for all of its applications, TEI began purchasing HAWE valves  in March 2004. TEI uses a wide range of HAWE components, including 75 to 100 size 02 to size 05 proportional directional control valves per year.

Most important was the fact that the HAWE valves would provide the stability required by TEI’s drilling attachments and limited access drills.

“When we started out, we were making solely static mounts,” said Frank. “There were no positioning systems, so instability wasn’t a problem. When we incorporated positioning capability, we started with a modest 20° side-to-side, which presented no safety issues to speak of.

Greater Safety an Added Bonus

“Still, sometimes a customer would fit a drill on a skid-steer at 20° on the top of the feed mast. With all the weight distributed at the top like that, the machine was actually prone to lifting to one side. No machine has ever tipped over, but the possibility was always there.

Control cabinet of TEI’s MME250, which uses proportional directional control valves from HAWE Hydraulics for muchimproved operation over previous models. The MME 250 requires 25 gpm of hydraulic flow at 1800 psi, making it ideal for residential and small industrial projects using mini excavators.

“The HAWE valves have solved that problem. With a more controlled flow of oil to the positioner, the attachment doesn’t jerk the way it used to, making it far safer for the operator.”

Frank also emphasized that since the company began installing its drilling attachments on another vendor’s equipment, they must deal with a limited amount of hydraulic flow to the attachment in these applications. This makes it essential that the available flow is used as efficiently as possible.

Additional benefits

The size and shape of the Hawe valves are also crucial factors in the successful function of the drill attachment. In fact, ergonomic and contemporary machine design depends on compact hydraulics. HAWE valves offer space savings of 20% to 40% compared to industry standard products.

“Because we can easily stack the different sizes, we keep the valve assemblies compact,” said Frank. “This is especially advantageous for an attachment because we try to save on weight wherever we can. Rather than having eight large valve sections, we can use two size 05 valve sections and six size 02 sections for our positioning functions. By keeping valve sizes smaller, the various combinations will ultimately mean less oil consumed.”

HAWE components are also capable of abating leakage because of their internal steel construction. So in the unlikely event that a drilling attachment is not properly manufactured, the Hawe valve can compensate minor engineering glitches.

Supplier Interaction

“We can send a schematic of what we have been doing as far as our valving and tell the HAWE engineers what we’d like to accomplish,” she said. “For instance, in our limited access drills, we needed to create a situation where if someone was tramming (performing mechanical adjustments), the drilling functions would halt for safety reasons. We used to do that with a simple hydraulic ball valve, which worked, but wasn’t the optimal method for several reasons. HAWE actually offered a way to do it on their valve bank, which puts us ahead of anyone else, technologically speaking.

“We constantly hear that our drilling attachments offer much better control,” Frank said. “Being a proportional valve, if you push on the handle, it only pushes out a certain amount of flow, so the operator can turn other things on. That, along with the safety and delivery, have been the real advantages.

“The bottom line is that everything that we use and manufacture uses a hydraulic valve, and every valve we use is a HAWE valve.”

For more information, visit www.teirockdrills.com or www.haweusa.com.