Mechanical & Fluid Systems

How To Make Pressure Switches That Last

Simple design principles for harsh operating conditions

Fluid control systems for many aerospace, industrial and heavy equipment applications require accurate, reliable pressure switching under harsh operating conditions. In these applications, the wrong pressure switch can cause catastrophic damage or even endanger human life.

Posted in: White Papers, Fluid Handling, Mechanical Components, Motion Control
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NEO Hunter Seeker Micro-Spacecraft and Mission Concept

Spacecraft mass and mission cost can be drastically reduced, including the ability to not only discover, but visit near Earth objects.

The area of research known as “Planetary Defense” is largely concerned with identifying and tracking asteroids that could impact Earth. The vast majority of asteroids that pose such a risk are known as “Near Earth Asteroids/Objects” or NEAs and NEOs. Some of them are unknown, un-cataloged, and untracked, but are presumed to orbit in Earth-like orbits, and periodically cross Earth’s orbit in a possibly threatening manner.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Imaging and visualization, Particulate matter (PM), Spacecraft
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Multipath, Multistage, Erosion-Resistive Valve for Downhole Flow Control

This valve can sustain the extremely high pressure of deep oil wells.

Multipath, multistage, erosion-resistant flow control valves have been developed that can sustain the extremely high pressure of deep oil wells. Fitting in the restricted available space and operating using limited power with a long lifetime are challenges for choke valves in the downhole environment of oil wells. These valves must control the flow rate from high-pressure oil reservoirs in the presence of fluids that have non-zero sand concentrations. This design consists of a digitized flow control valve with multipath and multistage pressure reduction structures. Specifically, the valve is configured as a set of parallel flow paths from the inlet to the outlet.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Drilling, Valves, Mining vehicles and equipment
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Passive Close-Off Feature for Sample Acquisition and Retention

This design has applications in the oil and gas field, and in coring to collect samples from human internal organs for medical applications.

NASA’s Jet Propulsion Laboratory, Pasadena, California

The current coring bit and percussive drilling style works very well for strong rocks; however, when coring into weak, crumbling rock, the core tends to break apart and simply fall out of the bit. These rocks, powder, and other debris can have useful information that is lost when they fall out of the bit after the core has been made, as there is no retention feature in place. A retention mechanism for coring into weak rocks was developed.

Posted in: Briefs, TSP, Mechanical Components, Mining vehicles and equipment
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Piezoelectric-Actuated Cryogenic Thermodynamic Vent Valve

Piezoceramic transducer elements with ceramic dielectric coating were successfully used in the actuator system.

Lyndon B. Johnson Space Center, Houston, Texas

Cryogenic fluid control valves require actuation that controls the geometric position of the orifice in a thermally stable manner. Traditional actuator devices may have various materials used in their construction that have varying CTEs (coefficients of thermal expansion) and therefore may shift (expand or contract) relative to the reference mounting points on the valve body. This leads to a lack of valve orifice control and leakage in the valve. To provide a more thermally stable control valve for cryogenic fluids, Dynamic Structures and Materials LLC (DSM LLC) provided a piezoelectric ceramic-driven actuation system on a cryogenic thermodynamic vent system (TVS) valve.

Posted in: Briefs, TSP, Mechanical Components, Sensors and actuators, Thermodynamics, Ceramics, Valves
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Amine Swingbed Payload

This system minimizes water and air loss.

Lyndon B. Johnson Space Center, Houston, Texas

The amine swingbed was in development for incorporation into Orion’s environmental control and life support system to remove metabolic carbon dioxide and humidity from the crew atmosphere. The compact, low-power swingbed uses space vacuum to regenerate itself. Direction was given by NASA to develop it for a payload experiment on ISS using the most recent engineering development laboratory unit. To minimize overboard humidity and crew cabin ullage losses, a method for removing humidity upstream of the amine swingbed had to be developed, along with a means to minimize overboard ullage losses when the swingbed cycled.

Posted in: Briefs, Mechanical Components, Carbon dioxide, Humidity, Life support systems, Spacecraft
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Decelerator System Simulation (DSS)

Lyndon B. Johnson Space Center, Houston, Texas

The Crew Exploration Vehicle Parachute Assembly System (CPAS) project conducts computer simulations to verify that requirements on flight performance, parachute loads, and terminal rate of descent are met. The objective of this work was to obtain a high-fidelity simulation of Orion crew capsule flight test vehicles during parachute flight.

Posted in: Briefs, TSP, Mechanical Components, Computer simulation, Entry, descent, and landing, Spacecraft
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Miniature, Multi-Functional, Self-Braking Vehicle

This vehicle is actuated by piezoelectric stacks through the fuselage walls.

NASA’s Jet Propulsion Laboratory, Pasadena, California

A novel, miniature, low-mass vehicle has been created that is driven by piezoelectric stacks and a resonance structure. Preliminary tests on similar mechanisms that are used to transmit electrical power across the wall showed efficiencies of the order of 90%. The transmitted mechanical power, and signals through metallic walls using the direct and indirect piezoelectric effects in similar motors, is of the order of 50%. The transmitted power is generated inside the vehicle body, and the mechanism is applicable to any robotic system that may require an ambulation of locomotion mechanism such as a rover, a miniature vehicle, a crawler, or a flying device.

Posted in: Briefs, TSP, Mechanical Components, Power electronics, On-board energy sources, Robotics, Nanotechnology
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Pulse-Echo Probe Mounting Fixture for Blind Alignment on Pipes

This technology enables an effective, real-time, in-service health monitoring system for steam pipes.

The probe and its mounting fixture are critical parts of the health monitoring of steam pipes. A high-temperature, piezoelectric transducer generates and receives ultrasonic waves, and the probe has to transmit the wave normal to the pipe surface. The mounting fixture is designed to allow for alignment of the probe even without a reference reflection, and thus enables blind alignment. In order to allow aligning of the probe normal to the surface of potential water condensation, and to secure intimate contact to the pipe surface, a novel mounting fixture was conceived and developed.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Mountings
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Zero-Gravity Mobile Robot Using ON/OFF Adhesive Pads and Inchworm Mechanism

The robot has applications in military reconnaissance, and as a commercial toy.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Inspection of the International Space Station and other manmade objects in space is difficult because of the microgravity environment. Robots are a promising approach to accomplish these inspection tasks and later repairs, but must be able to maneuver across the surfaces. Because there is no gravity, the robot is at high risk of floating away, necessitating grippers that can adhere to the surface and resist the forces and torques of inspecting and moving on the structure.

Posted in: Briefs, Mechanical Components, Terrain, Robotics, Spacecraft
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