Motion Control

Improving Stirling Engine Performance Through Optimized Piston and Displacer Motion

Stirling engines typically achieve high efficiency, but lack power density. Low power density prevents them from being used in many applications where internal combustion engines are viable competitors, and increases system costs in applications that require Stirling engines. This limits their operating envelope in both terrestrial and space applications. Sinusoidal piston and displacer motion is one of the causes of low power density. Previous work proposed solving this problem by replacing sinusoidal waveforms with waveforms that more closely approximate those of the ideal Stirling cycle. However, when working with real engines, imposing ideal waveforms has been shown to reduce power density and efficiency due to increased pressure drop through the regenerator and heat exchangers.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling, Motors & Drives

Read More >>

Linear Motor

The LinX® linear motor from Anca Motion USA (Wixom, MI) delivers a continuous force from 333 N to 665 N, and peak force from 2136 N to 4272 N. It features a cylindrical design with a thermal barrier that helps separate and remove heat from the motor. The motor’s zero net attractive forces eliminate the downforce associated with flatbed motors. Its cylindrical profile makes the system compact, effectively fitting into a space similar to that required by a regular ball-screw and circular motor. The motors are fully sealed and rated to IP67 or optional IP69K, making them well suited for machine tool and food processing systems. The motor can be enabled with an algorithm that increases axis stiffness and helps to minimize axis deflection with greater accuracy.

Posted in: Products, Motors & Drives

Read More >>

Optical Encoders

MICROMO (Clearwater, FL) announced the FAULHABER high-precision IER3 and IERS3 optical encoders. Both encoders deliver two-channel quadrature signals and an additional index signal. They can position a FAULHABER micro DC motor or brushless DC servomotor with a typical accuracy of 0.1° to 0.3°. The encoders combine the LED, photodetectors, analysis unit, and interpolation levels on one chip. They lengthen motors by 15.5 to 18.5 mm. Both encoders are also available with line drivers that generate complementary output signals and make data transmission resistant to electrical interference, especially in encoders with long connecting cables. The IER3 encoder has a resolution of up to 10,000 lines per revolution, and achieves an angular resolution of 0.009° with the evaluation of 40,000 edges per revolution. The IERS3-500 provides resolutions of 250 and 500 lines per revolution.

Posted in: Products, Electronics & Computers, Motors & Drives, Optical Components, Optics

Read More >>

Magnetic Relief Valve

A side view of the relief valve sections (left), and a view inside the relief valve (right). A magnetically retained pressure-relief valve enables quick-open on/off operation when overpressure is reached.Inventors at NASA’s Kennedy Space Center have developed a magnetically retained, fast-response pressure relief valve that is designed to fully open at precise cracking pressures, and that operates in a fully open/fully closed manner. The use of a magnetically controlled relief valve, as opposed to a spring-based relief valve, enables quick-open on/off relief operation when overpressure is reached. This is due to the rapid decay of the magnetic field as the fluid medium pushes the valve poppet to an open position. Spring-based relief valves require increasing pressure and force to continually compress the spring and open the relief valve. This requirement greatly complicates the design of a system relief mechanism. A magnetic relief valve reduces these design complexities by eliminating the spring.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Work Piece Cleaning Apparatus and Method with Pulsating Mixture of Liquid and Gas

NASA Goddard’s scientists have developed a novel, volatile organic compound (VOC)-free system for cleaning tubing and piping that significantly reduces cost and carbon consumption. The innovative technology enables the use of deionized water in place of costlier isopropyl alcohol (IPA), and does not create any waste for which costly disposal is usually required. It uses nitrogen bubbles in water, which act as a scrubbing agent to clean equipment. The cleaning system quickly and precisely removes all foreign matter from tubing and piping.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Safety Drain System for Fluid Reservoir

Researchers at NASA’s Marshall Space Flight Center have developed a system that reduces the entrapment risks associated with a pool or spa’s recirculation drain. The technology prevents hazards caused by suction forces on the body, hair, clothing, or other articles. Employing a novel configuration of drainage openings along with parallel paths for water flow, the system redistributes force over a much larger area, minimizing suction force at any localized area. With more efficient drainage and recirculation, the device improves performance, increases safety, and decreases operating costs. The technology can also provide thorough chemical mixing, which improves processes in systems and allows continued operation in the event of localized debris clogging a portion of the recirculation area. All of these benefits come without a protrusive drain cover, leaving the area safe and aesthetically pleasing.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

Temperature-Compensating PMT Housing

Shrinking or contracting light guides is a problem when photomultiplier tubes (PMTs) are glued to the guides. If there is no way to allow movement of the PMTs, when the temperature goes down, the light guide contracts and breaks the glue joint. The PMTs cannot be left loose to rattle around inside the detector. They must be held precisely, yet gently, and allowed to move.

Posted in: Briefs, Mechanical Components, Mechanics, Fluid Handling

Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.