fluidics


Also found in: Dictionary, Legal, Wikipedia.

fluidics,

branch of engineering and technology concerned with the development of equivalents of various electronic circuits using movements of fluid rather than movements of electric charge. The basic devices used in fluidics are specially designed valves that, like transistors, can be arranged to act as amplifiers and logic circuits. The principal advantage of fluidic systems is that they can be designed to tolerate conditions under which electronic systems could not possibly operate. For example, a fluidic system could operate in the exhaust of a rocket, using the exhaust as its working fluid. Fluidic systems are also advantageous where the system output is to be a flow of fluid, as in a carburetor.

Fluidics

 

(also, pneumonics), a branch of pneumatic automation that deals with the study, development, and use of devices (elements) that operate on the basis of aerohydrodynamic effects, such as momentum interaction, wall attachment (or wall reattachment), creation of turbulence of the stream in a laminar jet, throttling of flows, and vortex generation.

In discrete momentum-interaction elements, the jets flowing out of the input channels deflect other jets coming from the supply channel or from other input channels; in this case the pressure and delivery of air at the output of the element vary according to the relay characteristic. In wall-attachment elements, the properties of boundary-layer flows are used to produce and signal storage. In turbulence elements a relay characteristic is produced by the transition from laminar to turbulent flow. Various aerohydrodynamic effects are used in continuous-operation fluidic elements. The functions of the controllable throttles (flow-type pneumatic resistances) that create pressure gradients in streams are performed by vortex jet elements in which the output pressure is varied by making the flow turbulent with a jet emerging from a control channel.

The elements and devices of fluidics are made mostly from plastics by investment casting, compression molding, or photochemical etching methods that create depressions on the surfaces of flat plates to form the jet elements and communication channels. When such plates are covered with caps having orifices for the admission and removal of air (supply; input and output signals), the results are finished fluidic devices.

Jet elements of various types are used in low-pressure fluidic systems, with excess input and output pressures of about 0.1–1 kilonewton per sq m (kN/m2), and in combined jet-diaphragm automatic systems, where the maximum standard pressures of the input and output signals in the system are about 100 kN/m2.

Fluidic devices use active elements, which have input, output, and supply channels, and passive elements, which have no supply channel. They are supplied from compressors, compressed-air cylinders, or centralized systems into which air is forced by a compressor. To ensure trouble-free operation of fluidic devices when the air contains dust, a semiclosed supply system is used (part of the air from the outputs of the pneumatic elements is returned to the supply channels) and a low excess pressure is generated in the area where the elements are located, thus inhibiting the penetration of dust particles from without.

Fluidic devices are used in industrial automatic control systems to perform various logic functions and in systems that include digital counters, shift registers, and units for the bit-by-bit comparison of numbers. Such devices are used to perform not only discrete operations, such as summing of signals and bit-by-bit comparison of codes, but also analog operations, such as conversion, amplification, and frequency modulation of signals.

Devices are constructed with fluidic elements that measure the input parameters of automatic systems, such as flow velocity, flow rate, absolute gas pressure, pressure ratios, temperature, time, linear dimensions, rate of rotation, acceleration, forces, torques, and certain magnetic and electrical quantities. Fluidic elements are used in industrial controllers, in indicators of gas concentration and the position of objects, and in other devices designed for automation of processes in the petroleum-refining, gas, and chemical industries and in machine building. Fluidic elements and devices have been developed for control systems of power installations, agricultural equipment, and transportation. Such devices function normally at high and low temperatures, are fireproof and explosion-proof, are not affected by inertial overloads and vibrations, and are not subject to radiation effects. Therefore, they are used in aviation, rocketry, and space technology and in nuclear power engineering. Fluidic elements are used in medical equipment, such as the control systems of apparatus for assisted circulation and artificial respiration.

The basic elements of fluidics are designed to operate with low power consumption, usually about 10–2 watt; jet switches analogous to such elements are made for powerful gas streams to control ventilating systems, to improve smoke-trapping processes in factory smokestacks, and to control the thrust of jet aircraft engines. Devices have been developed for hydraulic-jet engineering based on the same principles as fluidic devices.

The USSR was the pioneer in the development of fluidics. Many other countries are now developing and studying fluidic elements and devices.

REFERENCES

Zalmanzon, L. A. Teoriia elementov pnevmoniki. Moscow, 1969.
Zalmanzon, L. A. Aerogidrodinamicheskie metody izmereniia vkhodnykh parametros avtomaticheskikh sistem. Moscow, 1973.
Elementy i ustroistva pnevmoavtomatiki nizkogo davleniia (struinoi tekhnikf): Katalog-spravochnik. Moscow, 1973.
Agregatnoe postroenie pnevmaticheskikh sistem upravleniia. Moscow, 1973.
Foster, K., and G. A. Parker. Fluidics: Components and Circuits. London, 1970.

L. A. ZALMANZON

fluidics

[flü′id·iks]
(engineering)
A control technology that employs fluid dynamic phenomena to perform sensing, control, information processing, and actuation functions without the use of moving mechanical parts.
References in periodicals archive ?
Parker Precision Fluidics has been providing innovative solutions since 1998 and maintains operations in New Hampshire, Pennsylvania, and North Carolina.
Headquartered in Columbia, Maryland, Bowles Fluidics Corporation is a world-class developer and manufacturer of fluid distribution products.
SFC Fluidics CEO Tony Cruz said VIC's model allowed his firm to focus on getting its disposable insulin pump patch to market, which it expects to do early next year.
20 -- Dolomite has introduced the Hotplate Adaptor - Chip Holder H which allows control over internal temperatures of micro fluidic chips without any disruptions to the fluid flow.
The Reveleris system surmounts the challenges of splitting fluidics and signal integration.
Written for students and practitioners of nanofabrication, this volume is split into sections for nanopatterning techniques and typical applications, with the latter half devoted to optics, organic devices, biological devices and fluidics.
Deerac Fluidics provides low-volume liquid handlers for the 50 nL-20 [micro]L range.
Designers can also use stepper motors to build laboratory analytical devices with motion control needs that may include stirring, fluidics, and sample selection.
During my travels to Chemical Engineering Departments, I have noticed that the Chemical Engineering Research is evolving in several fascinating new directions and chemical engineers are active in advancing the knowledge in such broad frontier areas as micro fluidics, fuel cells, molecular dynamics, tissue engineering, regenerative medicine, bioinformatics, advanced materials etc.
During his year in office Derek aims to help raise the pounds 15,000 necessary to buy a Fluidics Wash Machine for the department.
Two technologies for removing heat from electronic devices--synthetic jets that rely on trains of turbulent air puffs, and a system that uses vibration to atomize cooling liquids such as water--were developed by Professor Ari Glezer and co-workers at the Georgia Institute of Technology's School of Mechanical Engineering, and licensed to Atlanta-based Innovative Fluidics.
The model 6810 is housed in two discrete enclosures - one for the electronics, the second the fluidics and sample oxidation.