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Cylinder's plastic disk simplifies air flow control

Article-Cylinder's plastic disk simplifies air flow control

Cylinder's plastic disk simplifies air flow control

Monee, IL--If you're a user of pneumatic systems, then you know what it takes to control air flow through a cylinder. You buy flow valves, screw them into ports on the cylinder body, then try to orient them in a way so that they don't gobble up critical machine space.

Now, engineers from Bimba Manufacturing Co. say they've found a better way. By incorporating a thin plastic disk within the body of a new air cylinder, they have created a flow control technique that eliminates the need for additional hardware and labor. Known as the Original Line II Air Cylinder, it incorporates the flow control technique within the cylinder body.

That's a stark departure for round-line, non-repairable stainless steel cylinders, which have traditionally been too small to incorporate flow controls. In the past, engineers typically controlled air flow by employing an external valve with a tapered needle. By controlling movement of the needle within the valve's orifice, they could meter the flow of air through the cylinder. The problem was, such systems took up more room than was available inside the cylinder.

To solve that problem, Bimba engineer Wayne Hays found a way to control air flow without the use of the tapered needle. His solution involves a thin plastic "flow gear," or disk, which fits into the inner diameter of either of the cylinder's end caps. The injection-molded thermoplastic disk incorporates gear teeth on the side, and a teardrop-shaped hole near its center. By rotating the disk, users can orient the teardrop-shaped hole so that it allows full flow through an exhaust orifice, or no flow, or any amount of flow between fully opened and fully closed.

Users can rotate the flow gear by turning a screw that mates with the teeth on the disk. To go from fully opened to fully closed requires anywhere from 15 to 19 turns of the screw.

In that sense, the flow gear technique actually offers superior control over traditional methods, Bimba engineers say. Because each turn of the screw results in just a 5%-6% change in air flow restriction, it provides a wider range of control than traditional methods. In contrast, tapered needle techniques typically go from fully opened to fully closed in about six turns. "The beauty of the concept is that it offers no additional size, and it provides greater flow control at the same time," Hays says.

For most, however, the unit's key advantage is its elimination of the labor and hardware associated with flow controls. "We have replaced the traditional flow control mechanism with a large diameter plastic piece that is very, very thin," notes William Kokum, director of marketing for Bimba. "It fits into the body of the cylinder, so it's much better for the user."

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By rotating the flow disk, air flow through the exhaust orifice is restricted. A screw mates with gear teeth on the side of the flow disk. Turning the screw changes the orientation of the teardrop-shaped hole in the disk.
Additional details...Contact Thomas Carlson, Bimba Mfg. Co., Monee, IL 60449; 708-534-8544 or

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