Magnetics improve pneumatic control
Sometimes innovation comes from transferring an idea that works well in one application to another. Lord Corporation recently applied the idea of using magnetic fluid, which has successfully worked in the suspension systems of trucks, and applied it to forklifts, prosthetic devices, and other products that are being commercialized this year.
When I met with Lord's vice-president Gerald Estes in March at the 2000 National Design Engineering Show, he explained that PHD and Parker-Hannifin are producing products that use Lord's magneto-rheological (MR) fluid for controlling position and velocity. Tol-O-Matic and Turn-Act are also looking into applying the technology in their products.
I was told that, instead of just two control positions-open and closed-MR fluid enables positioning control for many positions between open and closed. One challenge for some MR fluid applications is the electric power source. In some applications, like prosthetics, the power source is a concern.
PHD's rotary devices use MR fluid for providing resistive torque that is proportional to the current supplied. These RM devices are suitable for use as rotary brakes and dampers, clutches, coupling, and tension-control devices in applications with pressures from five to 150 psi.
Parker-Hannifin is beginning to look at applications for MR fluid for use with their 2MA cylinders. "Controlling MR fluid is really preferable to controlling air in many applications," says Jim Crabb, a Parker Hannifin engineer. Parker's system concept combines a linear resistance device, using magneto-rheological fluid, that is placed parallel with a cylinder.
MR fluid changes from a fluid state to a semi-solid state that is directly proportional to the magnetic field applied to it. The material contains magnetic particles that form a dense network of chains when a magnetic force is applied to them. When the magnetic fluid is removed, particles revert to their free, unchained form quickly and easily for allowing movement of pneumatic actuators.
For more information on MR fluid, go to Lord's website, www.mrfluid.com, www.designnews.com, or Circle 583.
This silicone tubing was formulated specifically for the pharmaceutical and medical markets. The company is capable of extruding tubing up to 4 inches OD-ID tolerances as low as plus or minus 0.001-with a temperature range of -60 to 460F. They extrude in a Class 10,000 Clean Room and offer platinum or peroxide cure systems. The tubing is manufactured from USP Class VI tested and approved materials, which are autoclave, ETO, and Gamma sterilization compatible.
Mox-Med Inc., 2316 W. Wisconsin St., Portage, WI 53901; FAX (608) 742-3197; www.mox-med.com.
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The B621BA Foot Pedal is 4x3-1/2x11/4 inches and is molded of a tough glass filled polypropylene. A soft bellow is housed within the body and is connected by a flexible 1/4-inch OD tube to a remote air switch. The 3 PDT air switch may be momentary, alternate action, or sequencing, and is available up to 25 amps, 1 hp at 125V ac, 2 hp at 250V ac. The product does not contain electrical contact or current and is recommended for operating rooms, and medical and dental equipment.
Pres:Air:Trol Corp., 1009 W. Boston Post Rd., Mamaroneck, NY 10543; FAX (914) 698-9456.; www.presair.com.
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Designed and built to medical standards, this Peristaltic Pump is recommended for angioscopy, arthroscopy, endoscopy, laparoscopy, irrigation, waste removal, infusion, or other surgical/patient care procedures. Fluids or media move up to 16 (liter)pm, through the tubing only; no pump part becomes wetted. The disposable, medical grade tubing is reportedly loaded and unloaded without mess or contamination, providing a new "pump" for every use.
Barnant Co., 28W092 Commercial Ave., Barrington, IL 60010; FAX 847-381-7053; www.barnant.com.
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These medical grade polysulfone HFC-39 high-flow couplings feature automatic shut-off valves to prevent drips when disconnected and eliminate the need for pinch clamps. Designed to replace heavy stainless steel connectors and fittings, they will withstand up to 25 autoclave cycles, ETO, Gamma, or E-Beam sterilization methods. Working pressure ranges from 0 to 125 psi, with temperatures from -40 to 280F. They have a 3/8-inch diameter flow path with hosebarbs for 3/8- or 1/2-inch tubing.
Colder Products Co., 1001 Westgate Dr., St. Paul, MN 55114; FAX (651) 645-5404; www.colder.com.
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The 7006 Series of diaphragm air compressors and vacuum pumps was developed for specific applications, such as medical and instrumentation. The series has an open flow rate of 7.2 (liter)pm, maximum pressure up to 36 psig, and maintains a maximum vacuum up to 25.4 inches Hg. It is designed to be quiet with an enclosed crankcase and features oil-less operation, low vibration, and upright or horizontal mounting.
Thomas Industries Inc, 1419 Illinois Ave., Sheboygan, WI 53082-0029; FAX (920) 457-4237; www.thomaspumps.com.
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The Multi-Clamp System is designed to be an improved method for laying out line runs. It provides a definite reference for measuring, when routing single lines, multiple runs of the same line diameter, or multiple runs of various diameters. Multiple runs can be stacked to conserve space and make installations more rigid. Both vertical and horizontal center line distances remain consistent for exact spacing and installation.
Hydro-Craft Inc., 1821 Rochester Industrial Dr., Rochester Hills, MI 48309; FAX (248) 652-0343; www.hydro-craft.com.
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Radial diaphragm valves
The DR Series diaphragm valve is designed to eliminate all entrapment areas, drain easily, and clean completely. It can be manufactured in a range of configurations to include multiple valves and multiple ports. The result can be a more compact flow stream with fewer valves, less piping, and fewer connection. In addition, they are available in 18 configurations with tube butt-weld and TS series sanitary fitting end connections.
Swagelock, 31400 Aurora Rd., Solon, OH 44139-2764; FAX (440) 349 5806; www.swagelok.com.
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The Inert Proportional Valve (IPV) is a proportional, solenoid-operated diaphragm isolation valve designed for use with corrosive or high-purity fluids commonly found in medical and clinical chemistry industries. Flow is proportional to the magnitude of the current into this 24V dc valve driver. The poppet and seat are configured to provide bubble tight leakage characteristics. The materials of all flow surfaces are inert and impervious to a range of aggressive fluids.
South Bend Controls, 1237 Northside Blvd., South Bend, IN 46615; FAX (219) 234-3948; www.sbcontrols.com.
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