Beswick Engineering: Small Regulator Offers Tight Pressure Control

Portable equipment designers who need tight pneumatic pressure regulation may now have a small but powerful solution. Beswick Engineering (Greenland, NH) has introduced a 28-gram regulator that holds outlet pressures to tolerances of (+-) 0.25 psi, thus making it possible for manufacturers of inkjet printers, semiconductor equipment, medical pumps, and fuel cell-powered devices to conserve power while honing performance.

The miniature PRD2 two-stage pressure regulator reportedly can handle wide swings in inlet pressure, even sudden jumps of almost 500 psi, while maintaining steady outlet pressures with no more than 0.25-psi variation. That capability, combined with its tiny, 1.8-inch diameter size, makes it a candidate for a new breed of portable applications that call for more tightly-constrained air flows.

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"You can get similar pressure control from much bigger regulators, but no regulator that we know of offers this kind of control in such a small package," notes Mike Donati, vice president of sales and marketing for Beswick Engineering.

Beswick engineers say that the miniature regulator offers tighter control because it employs cast, precision-machined parts, especially in its valve seats. Also, in contrast to most miniature regulators, which are often constructed with molded plastic parts, PRD2s are made from brass, aluminum, or stainless steel.

The company's engineers acknowledge that such construction results in an economic trade-off: The two-stage PRD2 costs $125, while a single-stage PRD runs $59. In contrast, many miniature regulators range from $10 to $25 in cost.

Still, the company says it has found a booming market for the technology, especially in fuel cell-powered devices for defense and aerospace applications. The regulator has, for example, been applied to fuel cells used to power such devices as night-vision goggles and field radios. Up to now, such systems have typically used batteries, which are bigger and heavier than fuel cells, and are accompanied by disposal issues.

In fuel cells, the new miniature pressure can be used to cut the weight and size of the fuel cell package, while simultaneously offering the precise fluid flows that hydrogen fuel cells need.

"They need to precisely maintain the pressure at about 30 psi so they don't damage the fuel cell stacks," notes Corey Marcotte, applications engineer and operations coordinator for Beswick Engineering.

Beswick's 28-gram pressure regulator can maintain outlet pressures within (+-)0.25 psi.

By doing so, the new pressure regulators take their place among a new breed of fluid power components that are seeing use in compact industrial fuel cells. Parker Hannifin (New Britain, CT), for example, now offers highly efficient compressors that are tailored for fuel cell applications. The compressors are being employed, along with other customized fluid power components, on a highly-publicized, fuel cell-powered scooter made by Vectrix Corp. (Newport, RI).

"The fuel cell business has helped get this technology off the ground, but there also appears to be a lot more applications for it," Donati says.

Indeed, the device has been employed on marine heaters and in small engines, where it regulates fuel flow. It is also making in-roads in inkjet printers, semiconductor etching equipment, portable dialysis machines and blood pumps, as well as bomb and chemical detectors. The device's selling point, its small size, is also its limitation, however; its 100 cc/min flow rate prevents its use in larger flow applications.

"It's really designed for portable equipment," Marcotte says. "Anyone who needs precise pressure regulation in a small package can use this."